Download 2nd Joint SFBD / SBCF Meeting

2nd Joint SFBD / SBCF Meeting
ABSTRACT
BOOK
WHEN DEVELOPMENT MEETS CELL BIOLOGY
April 26th - 29th, 2017 / Lyon, France
Organizing Committee:
Antoine Guichet - Krzysztof Jagla - René-Marc Mège
Samir Merabet - Grégoire Michaux - Michèle Studer
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 1
ACKNOWLEDGEMENTS
INSTITUTIONAL PARTNERS
SPONSORS
2 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
INTRODUCTION
The conference will be held in front of the wonderful park
Tête d’Or in Lyon, the capital of gastronomy that has been
listed by UNESCO as a World Heritage Site.
The goal of the conference is to highlight how fundamental
questions in Developmental Biology and Cell Biology are
intimately linked. Presentations from prestigious invited
speakers and selected short talks will cover latest progresses
in gene regulation, nuclear architecture, cell polarity, cell
migration, signalling, morphogenesis, reprogramming,
signalling and emergent models. Time will be devoted to
stimulate exchanges and share expertise.
Organizing Committee:
Antoine Guichet - Krzysztof Jagla - René-Marc Mège
Samir Merabet - Grégoire Michaux - Michèle Studer
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 3
TABLE OF CONTENTS
SCIENTIFIC PROGRAM05
POSTERS SESSION 179
POSTERS SESSION 2 121
AUTHORS INDEX
163
LIST OF PARTICIPANTS
171
USEFUL INFORMATION
179
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SCIENTIFIC
PROGRAM
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 5
SCIENTIFIC PROGRAM
WEDNESDAY 26th APRIL
04:00-06:00 pm
Registration
06:00-07:00 pm
Cocktail
07:00-08:00 pm
Keynote Seminar - Yohanns Bellaiche
«Mitosis and epithelial morphogenesis»
THURSDAY 27th APRIL
09:00-11:45 am
Plenary Session 1: NUCLEAR ARCHITECTURE, EPIGENETICS
09:00-09:30 am Invited Seminar: Frédéric Bantignies
«Interphase chromosome organization depends on an intricate balance
between folding and homologous pairing»
09:30-10:00 am
2 selected short talks: Yad Ghavi-Helm & Benoit Souquet
10:00-10:30 am
Coffee break
10:30-10:45 am
Chemometec Presentation
10:45-11:15 am
Invited Seminar: Francesca Palladino
«Maintenance of germ cell identity by the C. elegans SET-2/SET1
histone methyltransferase»
11:15-11:45 am
2 selected short talks: Jeremy Dufourt & Bruno Cadot
11:45-12:45 pm
Keynote Seminar - Julie Ahringer
«Genome architecture and transcription regulation in C. elegans»
12:45-03:30 pm
Lunch buffet and Poster Session 1 (Even numbers)
03:30-06:15 pm
In Parallel:
Sessions 1: GENE REGULATION AND 2: CELL POLARITY & TRAFFIC
03:30-04:00 pm
Invited Seminar
- Session 1: François Spitz
«Molecular mechanisms organizing and regulating
long-distance relationships in gene expression»
- Session 2: Anne Spang
«Regulation of transport through the endocytic pathway»
04:00-04:30 pm
2 selected short talks / Session:
• Session 1: Stéphanie Debrulle & Cristiana Dondi
• Session 2: Florence Besse & Nicolas Chartier
04:30-05:00 pm
Coffee break
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SCIENTIFIC PROGRAM
05:00-05:30 pm
Invited Seminar
- Session 1: Anna Mattout
«A post-transcriptional mechanism specialized in silencing H3K27me3
genomic regions in C.elegans»
05:30-06:15 pm
- Session 2: Richard Anderson
«Agonist-Stimulated Scaffolding of the full PI 3-kinase pathway»
3 selected short talks / Session:
• Session 1: Pascale Gilardi-Hebenstreit, Elena De Sena & Leiore Ajuria Astobiza
• Session 2: Nicolas Taulet, Delphine Delacour & Ann Wehman
06:15-06:45 pm
Invited Seminar
- Session 1: Alfonso Martinez-Arias
«Genetically supervised axial (self)
organization in aggregates of mouse embryonic stem cells»
- Session 2: Wieland Huttner
«On the role of human-specific genes, notably ARHGAP11B,
in neural stem cell amplification and neocortex expansion
in development and human evolution»
07:00 pm
Free dinner
FRIDAY 28th APRIL
09:00-11:45 am
Plenary Session 2: SIGNALLING
09:00-09:30 am
Invited Seminar: Eduardo Moreno
«Regulating the cellular composition of our bodies using Fitness Fingerprints»
09:30-10:00 am
Invited Seminar: Catherine Rabouille
«Stress assemblies in the control of anabolic pathways»
10:00-10:30 am
Coffee break
10:30-10:45 am
Alvéole Presentation
10:45-11:00 am
MP Biomedicals Presentation
11:00-11:30 am
Invited Seminar: Benoît Ladoux
«Physical control of cell extrusion and death in epithelia»
11:30-12:00 am
2 selected short talks: Mélina Heuzé & Mohamad Ali Fawal
12:00-12:30 pm
Invited Seminar: Sylvie Schneider-Maunoury
«Primary cilia in forebrain morphogenesis»
12:30-03:30 pm Lunch buffet and Poster Session 2 (Odd numbers)
AG SFBD (02:00pm)
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SCIENTIFIC PROGRAM
03:30-06:15 pm
In Parallel:
Sessions 3: EMERGENT MODELS & EVOLUTION AND 4: CELL MIGRATION & ADHESION
03:30-04.00 pm
Invited Seminar
- Session 3: Nipam Patel
«The Evolution of Arthropod Body Patterning:
Insights from Genome Editing in the Crustacean, Parhyale»
- Session 4: Pierre-François Lenne
«Shaping cell contacts during tissue morphogenesis»
04:00-04:30 pm
2 selected short talks / Session:
• Session 3: Cyril Basquin & Marco Grillo
• Session 4: François Fagotto & Fabiana Cerqueira-Campos
04:30-05:00 pm
Coffee break
05:00-05:30 pm
Invited Seminar
- Session 3: Patrick Lemaire
«Embryonic inductions may constrain the evolution
of ascidian embryonic morphogenesis»
- Session 4: David Sherwood
«Mechanistic insights into cell invasion: Lessons from the C. elegans anchor cell»
05:30-06:00 pm
2 selected short talks / Session:
• Session 3: Abderrahman Khila & Frank Schnorrer
• Session 4: Anne Pora & Sandrine Etienne-Manneville
06:00-06:30 pm
Invited Seminar: François Payre
06:30-06:50 pm
SFBD Thesis Price
07:30-08:00 pm
Dinner at «La Brasserie Georges» (Lyon 69002)
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SCIENTIFIC PROGRAM
SATURDAY 29th APRIL
09:00-11:45 am
Plenary Session 3: MORPHOGENESIS & ORGANOGENESIS
09:00-09:30 am
Invited Seminar: Renata Basto
«Spindle morphology tailoring trough time:
Differences in spindle architecture during mouse neurogenesis»
09:30-10:00 am
Invited Seminar: Jordi Casanova
«Progenitor cells and cell migration in Drosophila morphogenesis»
10:00-10:30 am
Coffee break
10:30-11:00 am
Invited Seminar: Christophe Marcelle
«A novel role for TGFβ signaling in regulating muscle cell fusion»
11:00-11:30 am
2 selected short talks: Mathilde Dumond & Bertrand Benazeraf
11:30-12:30 pm
Keynote Seminar - Olivier Pourquié
«Excitable dynamics of the segmentation clock»
12:30-12:45 pm
Concluding remarks and departure
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SESSION 1 - WEDNESDAY 26th APRIL
WEDNESDAY 26th APRIL
04:00-06:00 pm
Registration
06:00-07:00 pm
Welcome drink
07:00-08:00 pm
Keynote Seminar - Yohanns Bellaiche
«Mitosis and epithelial morphogenesis»
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 11
Yohanns Bellaïche
CNRS, Inserm, Curie Institute Paris, France
Keynote Speaker
Mitosis and epithelial morphogenesis
Q
uestions related to embryo shape or morphogenesis have haunted developmental biologists
for decades. Recent advances in imaging, cell biology, signal transduction and biophysics
have framed the study of tissue morphogenesis in terms of collective cell dynamics and
the interplay between biochemical and mechanical processes. Recent findings have confirmed that
proliferative epithelial tissues reshape via morphogenetic processes such as cell shape change
and cell rearrangements. Yet cell division remodels adherent junctions and modulates both tissue
mechanics and tissue dynamics. Therefore its role and interplay with the other morphogenetic
processes need to be understood to decipher the mechanisms of tissue morphogenesis. Moreover,
given the large size of some proliferative tissues, challenging questions can be addressed: How do
local and long-range mechanical effects contribute to tissue dynamics ? How do the combinations of
several signaling pathways or gene expression patterns specify distinct local cell dynamics leading
to the emergence of several morphogenetic movements within a given tissue ? During my talk I
will describe some of our latest works that aim to understand the mechanisms of mitotic spindle
orientation, propagation of cell polarization through division and how cell division impacts on the
global shape and organization of epithelial tissue.
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SESSION 1 - PART 1 - THURSDAY 27th APRIL
NUCLEAR ARCHITECTURE, EPIGENETICS
THURSDAY 27th APRIL
09:00-11:45 am
Plenary Session 1: NUCLEAR ARCHITECTURE, EPIGENETICS
09:00-09:30 am Invited Seminar: Frédéric Bantignies
«Interphase chromosome organization depends on an intricate balance
between folding and homologous pairing»
09:30-10:00 am
2 selected short talks: Yad Ghavi-Helm & Benoit Souquet
10:00-10:30 am
Coffee break
10:30-10:45 am
Chemometec Presentation
10:45-11:15 am
Invited Seminar: Francesca Palladino
«Maintenance of germ cell identity by the C. elegans
SET-2/SET1 histone methyltransferase»
11:15-11:45 am
2 selected short talks: Jeremy Dufourt & Bruno Cadot
11:45-12:45 pm
Keynote Seminar - Julie Ahringer
«Genome architecture and transcription regulation in C. elegans»
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Frédéric Bantignies
Quentin Szabo1, Filippo Ciabrelli1, Boyan Bonev1,
Giorgio Papadopoulos1, Niroshi Senaratne2, Eric Joyce2,
Brian Beliveau2, Tiao Xie3, Ting Wu2 and Giacomo Cavalli1
Invited Speaker
1. Institut de Génétique Humaine, CNRS-UPR 1142, Montpellier, France
2. Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
3. Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
Interphase chromosome organization depends on an
intricate balance between folding and homologous pairing
A
s more and more genomes are being explored and annotated, recent 3C (chromosome
conformation capture) analyses and its high throughput adaptation (Hi-C) have revealed the
existence of specific three-dimensional (3D) chromosomal structures named ‘Topologically
Associating Domains’ or TADs. These domains are considered as intrinsic architectural property of
chromosomes, which contribute to the folding of the genome and its partition into well-demarcated
epigenetic domains. Drosophila or mammalian TADs have specific chromatin signatures,
corresponding to active or repressive chromatin types, including the Polycomb repressed domains.
TADs are therefore playing important functional roles in the control of gene expression and
development. An additional level of folding corresponds to long-range interactions between TADs
of the same chromatin type [1, 2], a property that could lead to the functional folding of the genome
during cell cycle. We now want to identify the genetic network that directs such chromosome folding.
T
o achieve this goal, we developed a new “Fluorescent in situ Hybridization” (FISH)-based
approach in Drosophila cells to measure long-range associations of TADs in high-throughput
manner. Indeed, the systematic measurement of inter-distances between two distinct
topological domains represents a good proxy for chromosome folding/looping. We developed
“Oligopaint» probes to produce dependable FISH probes against single copy loci for large-scale
usage [3]. Using this strategy, we “painted” two Polycomb TADs separated by approximately 0.5 Mb
along the chromosome arm and used their inter-distance as a read-out for chromatin folding.
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Frédéric Bantignies
W
e then set up a cell culture-based high-throughput FISH assay (Hi-FISH) to screen by
RNA interference for the function of approximately 180 candidate genes. In parallel,
we developed an algorithm for automated image analysis, allowing us to score several
chromosomal features in a high-throughput manner. Hi-FISH enabled us to identify several new
genes that can enhance or antagonize the folding between two genomic domains. Interestingly, we
found that these genes also influence the pairing of homologous chromosomes, leading to a model
where folding and pairing are intimately linked for chromosome conformation. The characterization
of their role combining Hi-C, transcriptomic analysis and high-resolution microscopy will give new
insights into the mechanisms that control 3D chromosome organization in interphase nuclei.
1. Rao SS, Huntley MH, Durand NC, Stamenova EK, Bochkov ID, Robinson JT, Sanborn AL, Machol I,
Omer AD, Lander ES, Aiden EL (2014). A 3D map of the human genome at kilobase resolution reveals
principles of chromatin looping. Cell 159:1665-1680.
2. Sexton T, Yaffe E, Kenigsberg E, Bantignies F, Leblanc B, Hoichman M, Parrinello H, Tanay A, Cavalli
G (2012). Three-Dimensional Folding and Functional Organization Principles of the Drosophila
Genome. Cell 148: 458-472.
3. Beliveau BJ, Boettiger AN, Avendaño MS, Jungmann R, McCole RB, Joyce EF, Kim-Kiselak C,
Bantignies F, Fonseka CY, Erceg J, Hannan MA, Hoang HG, Colognori D, Lee JT, Shih WM, Yin P,
Zhuang X, Wu CT (2015). Single-molecule super-resolution imaging of chromosomes and in situ
haplotype visualization using Oligopaint FISH probes. Nature Communications 6: 7147.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 17
SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Yad Ghavi-Helm
Sascha Meiers, Aleksander Jankowski, Rebecca Rodriguez Viales,
Jan O. Korbel and Eileen E. M. Furlong
Selected
Oral
nication
Commu
Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
The functional impact of structural rearrangements on
transcription regulation in 3D during embryogenesis
I
n multicellular organisms, embryonic development requires the coordinated expression of genes in
both a temporal- and tissue-specific manner. This complex regulation is controlled by the binding
of sequence-specific transcription factors to enhancer elements or cis-regulatory modules
(CRMs), which can be located at great distances from their target gene. Chromatin conformation
studies have shown that gene activation by remote enhancers is associated with the establishment
of a chromatin loop. However, our previous work indicates that enhancer-promoter loops are often
formed prior to transcription, suggesting that chromatin loops are necessary, but not sufficient,
for gene activation. The precise link between chromatin organization and transcription regulation
remains therefore unclear.
I
n order to resolve the interplay between chromatin loops and the regulation of gene expression,
we studied the effects of minor and major genome rearrangements on both transcription and
chromatin conformation. First, to examine the effect of small and targeted mutations or deletions,
we used CRISPR-Cas9 genome editing to produce targeted deletions of interacting regions in
Drosophila. Second, to examine the effect of major rearrangements, we are taking advantage of
D. melanogaster lines with highly scrambled chromosomes, called balancer chromosomes, which
are the product of multiple chromosomal rearrangements generated by X-ray mutagenesis. These
combined approaches are allowing us to decipher the link between chromatin organization and
transcription regulation at multiple scales, for example, by examining the transcriptional effect of
the precise deletion of an individual enhancer to a major modification disrupting a large chromatin
domain. The results are revealing surprising insights into the relationship between chromatin
topology in cis and transcriptional regulation.
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Benoit Souquet
Ellen Freed*2, Alessandro Berto*1, Vedrana Andric1,
B. Reina-San-Martin3, Elizabeth Lacy2, Valérie Doye1
Selected
Oral
nication
Commu
1. Jacques Monod Institute, UMR7592 CNRS - Paris Diderot University, Paris, France
2. Developmental Biology Program, Memorial Sloan Kettering, New York, USA 3-IGBMC,
Illkirch, France *These authors contributed equally to this work
Nup133 deficiencies affect nuclear pore basket assembly
and embryonic stem cell viability during differentiation.
I
n eukaryotes, nucleocytoplasmic transport occurs through nuclear pore complexes (NPCs), large
assemblies composed of ~30 distinct proteins (Nups). The Y-complex, a major structural NPC
component, encompasses 9 distinct Nups, including Nup133. Studies on the Nup133-/- mouse
revealed the requirement of this gene for embryonic development (a). Interestingly, the lack of
Nup133 does not affect mouse embryonic stem cell (mESC) self-renewal but impairs their neural
differentiation (a).
T
he differentiation properties of Nup133-/- mESC were further investigated using neural
and mesoendodermal differentiation. From day 2 and continuing on subsequent days of
differentiation, Nup133-/- cells exhibited high levels of cell death relative to WT. However,
the few Nup133-/- cells that escaped cell death properly repressed markers of pluripotency and
acquired a differentiated fate based on morphology and marker expression.
I
n view of a previous study revealing the contribution of the Nup133 to interphasic NPC assembly
(b), we combined various approaches to visualize pore assembly and dynamics in pluripotent
and differentiating Nup133-/- cells. These analyses revealed that in mESCs Nup133 is largely
dispensable for NPC assembly. However, we found that in both pluripotent and differentiating
Nup133-/- cells, about half of the NPCs do not contain Tpr (the major component of the nuclear
basket). Although Nup153 tethers Tpr to the NPC, Nup153 levels at the NE are comparable between
WT and Nup133-/- cells. However, we discovered that in the absence of Nup133, Nup153 dynamics
is increased at the NE. By expressing various truncated alleles of Nup133 in Nup133-/- mESCs we
found that the middle domain of Nup133 is critical for proper NPC basket assembly. The differentiation
capacity of mESCs lacking the middle domain of Nup133 is under investigation. Our work thus
provides new insight on NPC basket assembly and further supports growing evidences of the role of
the NPC basket in development.
(a) Lupu (2008) Dev.Cell; (b) Doucet (2010) Cell
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 19
SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
CHEMOMETEC PRESENTATION
MASANTE Cyril
Sales Manager, Products Specialist
Cell analysis based on imaging cytometry for :
- Precise and specific cell counting
- Apoptosis measurement
- Cell cycle analysis
- (no flow) Cytometry
C
hemoMetec develops, manufactures and sells high quality automated Image Cytometer’s
within cell counters, which as the only ones on the market can count aggregated cells,
adipose derived stem cells, cells growing on microcarriers with the highest precision. We also
offer advanced cell analyzers to help streamline processes for maximum efficiency. Our instruments
are indeed able to precisely characterize apoptosis, determine the specific phase of the cycle for
each cell, monitor GFP transfection efficiency (fluorescence and mortality) and to perform 16 colors
cytometry to detect the commonly used fluorophores. Our machines are widely used in fields such
as cancer research, stem cell research, production and quality control of a number of products such
as pharmaceuticals, beer, animal semen and milk. 21 CFR Part 11 is also valued highly to have the
highest standards. Our products are held in high regard because of their high quality and precision
as well as the “ease of use” advanced cell analysis. We value our customers. Therefore, our policy is
“no hidden costs” - no service agreements, high level of support and free software updates.
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Francesca Palladino
LBMC, École Normale Supérieure de Lyon, France
Invited Speaker
Maintenance of germ cell identity by the C. elegans SET-2/
SET1 histone methyltransferase
G
erm cells must transmit genetic information across generations, and produce gametes
while also maintaining the potential to form all cell types after fertilization. Dynamic changes
in chromatin structure are essential for these processes. Methylation of histone H3 Lys 4
(H3K4me) is a universally conserved mark deposited by the highly conserved SET1/MLL family histone
methyltransferases and associated with transcriptionally active regions of chromatin. However,
convincing evidence for an instructive role for H3K4me3 in transcription is lacking, and H3K4me3 is
likely to play context-dependent functions to modulate gene expression. We have shown that in the
germline, the C. elegans SET1 homologue SET-2 and H3K4me3 are required to maintain germline
immortality (passage of germcells from one generation to the next) and totipotency (the ability of
germcells to differentiate into all cell types). Mutant animals lacking set-2 show a progressive loss
of fertility across generations accompanied by the expression of somatic genes in the germline and
conversion of germ cells into somatic cells. These results suggest that in the germline H3K4me3 is
required to repress somatic gene expression. In order to understand how SET-2 dependent H3K4me3
regulates gene expression we are using biochemical approaches and transcriptomics analysis. I will
present data showing that SET-2 interacts with a complex network of epigenetic factors, and that
these intearactions are likely to influence the outcome of H3K4 methylation on gene expression. In
addition, ongoing gene expression profiling will reveal how SET-2 and interacting chromatin factors
cooperate to differentially influence gene expression in the germline and soma.
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Jeremy Dufourt
Jérémy Dufourt14, Gwénaëlle Bontonou1, Aymeric Chartier1,
Anne-Cécile Meunier1, Stéphanie Pierson1, Paul F. Harrison2, 3,
Catherine Papin1, Traude H. Beilharz3 and Martine Simonelig1
Selected
Oral
nication
Commu
1 mRNA Regulation and Development, Institute of Human Genetics, CNRS UPR1142 and University of Montpellier, France.
2 Monash Bioinformatics Platform, Monash University, Melbourne, VIC, Australia.
3 Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC,
3800, Australia.
4 Present adress, Transcription regulation during development, IGMM, CNRS, Univ. Montpellier, Montpellier, France
piRNAs and Aubergine cooperate with the Wispy poly(A)
polymerase to stabilize mRNAs in the germ plasm
P
iwi-interacting RNAs (piRNAs) and PIWI proteins play a crucial role in germ cells by repressing
transposable elements and regulating gene expression. In Drosophila, maternal piRNAs are
loaded into the embryo mostly bound to the PIWI protein Aubergine (Aub). Aub targets maternal
mRNAs through incomplete base-pairing with piRNAs and can induce their destabilization in the
somatic part of the embryo. Paradoxically, these Aub-dependent unstable mRNAs encode germ
cell determinants that are selectively stabilized in the germ plasm. Here we show that piRNAs and
Aub actively protect germ cell mRNAs in the germ plasm. Aub directly interacts with the germlinespecific poly(A) polymerase Wispy, thus leading to mRNA polyadenylation and stabilization in the
germ plasm. These results reveal an unexpected role of piRNAs in mRNA stabilization and identify
Aub as an interactor of Wispy for mRNA polyadenylation. They further highlight the role of Aub and
piRNAs in embryonic patterning through two opposite functions.
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SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Bruno Cadot
Yin Loon Lee , Radoslaw M. Sobota , Alessandra Calvi , Kamel Mamchaoui ,
Brian Burke , Jan Schmoranzer , Edgar Gomes, Bruno Cadot
Selected
Oral
nication
Commu
IMB, Singapore; EMBL, Heidelberg; University of Leicester, Charité, Berlin, Germany;
IMM, Lisbon, Portugal ; Research Center in Myology, Paris, France.
Linc Complex and Microtubule nucleation in muscle cells
N
esprins are known to link the nucleus to the cytoskeleton and thereby mediate nuclear
positioning in skeletal muscle cell s via the recruitment of kinesin-1 to the nuclear envelope
(NE). The NE recruits centrosomal proteins and thus microtubule nucleation capacity during
skeletal muscle formation but the mechanism remains unknown. Here, we performed a proximitydependent biotin identification screen, BioID, and identified three centrosomal proteins (Akap450,
Pericentrin and Pcm1) to preferentially associate with Nesprin-1α during myogenic differentiation.
We show that Nesprin-1α, together with Sun1/2 at the inner nuclear membrane, is required for NE
localization of these centrosomal proteins and microtubule nucleation via Akap450. Using computer
simulation and cell culture systems, we demonstrate that Nesprin-1-dependent microtubule
nucleation from the NE is required for proper nuclear positioning in skeletal muscle cells. Our data
thus reveals a novel role for Nesprin-1 in nuclear positioning through recruitment of Akap450mediated microtubule nucleation activity to the NE.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 23
SESSION 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Julie Ahringer
The Gurdon Institute
University of Cambridge, UK
Keynote Speaker
Genome architecture and transcription regulation in C. elegans
A
ll nuclear events take place in the context of chromatin, the organization of genomic DNA with
histones and hundreds of associated proteins and RNAs. Regulating the composition and
structure of chromatin controls transcription and other nuclear processes, and is important
for cell fate decisions, the expression of cell identity, the maintenance of pluripotency, and the
transformation to cancer. We use C. elegans to study chromatin regulation in gene expression and
genome organization in a whole organismal context, because it has a complement of core chromatin
factors very similar to that of humans, a small well-annotated genome (30x smaller than human),
RNAi for loss of function studies, and well-characterised cell fates. I will discuss our work on the
properties and activities of promoters and enhancers, the regulation and function of chromatin
domains, and interactions between regulatory elements.
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26 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 1 - PART 2 - THURSDAY 27th APRIL
GENE REGULATION AND CELL POLARITY & TRAFFIC
THURSDAY 27th APRIL
03:30-06:15 pm
In Parallel:
Sessions 1: GENE REGULATION AND 2: CELL POLARITY & TRAFFIC
03:30-04:00 pm
Invited Seminar
- Session 1: François Spitz
«Molecular mechanisms organizing and regulating
long-distance relationships in gene expression»
- Session 2: Anne Spang
«Regulation of transport through the endocytic pathway»
04:00-04:30 pm
2 selected short talks / Session:
• Session 1: Stéphanie Debrulle & Cristiana Dondi
• Session 2: Florence Besse & Nicolas Chartier
04:30-05:00 pm
Coffee break
05:00-05:30 pm
Invited Seminar
- Session 1: Anna Mattout
«A post-transcriptional mechanism specialized in silencing H3K27me3 genomic regions in C.elegans»
- Session 2: Richard Anderson
«Agonist-Stimulated Scaffolding of the full PI 3-kinase pathway»
05:30-06:00 pm
3 selected short talks / Session:
• Session 1: Pascale Gilardi-Hebenstreit, Elena De Sena & Leiore Ajuria-Astobiza
• Session 2: Nicolas Taulet, Delphine Delacour & Ann Wehman
06:00-06:30 pm
Invited Seminar
- Session 1: Alfonso Martinez-Arias
«Genetically supervised axial (self)
organization in aggregates of mouse embryonic stem cells»
- Session 2: Wieland Huttner
«On the role of human-speci c genes, notably ARHGAP11B,
in neural stem cell ampli cation and neocortex expansion
in development and human evolution»
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 27
SESSION 1: GENE REGULATION
François Spitz
(Epi)genomics of animal development
Pasteur Institute - Paris, France
Molecular mechanisms organizing and regulating
long-distance relationships in gene expression
Invited Speaker
I
n vertebrates, the regulatory elements that control gene expression can lie several hundreds
kilobases away from the promoter they influence. The biological role of those distant elements
is particularly important during embryogenesis, as they often provide decisive instruction to key
developmental regulators. Because of the distances involved, the activity of these elements is not
only defined by their intrinsic regulatory potential, but also by their ability to transfer it to their target
genes. Hence, their biological function is closely associated with the 3D-organization of the genome.
Recent results identified critical roles of “topologically-associating domains” (TADs) in regulating
gene expression and enhancer-promoter interactions, but the underlying mechanisms are still poorly
understood and highly debated.
T
o understand how TADs influence enhancer-promoter interactions, we have systematically
dissected few large genomic loci with in vivo chromosomal engineering techniques.
These studies reveal that TADs are not simply defining boundaries to enhancer-promoter
interactions. Our data show that the compaction associated with TADs is essential to promote longdistance functional interactions. Furthermore, the distribution of enhancer responsiveness is not
homogeneous or continuous within TADs. TADs display therefore an internal organisation, which
appear to be defined more by the relative distribution of cis-elements than by the distance separating
them. We show that this structure can modulate enhancer-promoter contact frequency and therefore
influence the functional outcomes of those interactions.
S
everal complexes have been proposed to contribute to the 3D conformation of the genome, but
the degree of their involvement has so far remained unclear. By deleting the cohesin loading
factor Nipbl, we observed a dramatic reorganization of all layers of genome organization.
TADs and associated loops vanish globally, even in absence of transcriptional changes. In contrast,
segregation into activity-dependent compartments is preserved and even reinforced, and the
absence of TADs unmasks a finer compartment structure that accurately reflects the underlying
linear chromatin landscape. Expression changes reflect a more local activity of regulatory elements,
suggesting that TADs foster long-distance interactions. I will discuss how these findings advance
our views of genome organisation.
28 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Anne Spang
Biozentzum, University of Basel, Switzerland
Invited Speaker
Regulation of transport through the endocytic pathway
E
ndocytosis plays an essential role in the cell surface expression of various proteins and in
signaling transduction pathways. The maturation from early to late endosomes requires the
coordination of multiple processes such as acidification, sorting of proteins into recycling
pathways and intraluminal vesicles, lipid exchange and Rab conversion, in which the loss of Rab5
from an endosome occurs concomitant to the acquisition of Rab7. We identified SAND-1/Mon1 as
the critical switch for Rab conversion in metazoa. SAND-1 serves a dual role in this process. First,
it interrupts the positive feedback loop of RAB-5 activation by displacing RABX-5 from endosomal
membranes and, second, as a RAB-7 GEF it times the recruitment of RAB-7. We are aiming to
understand the cross-talk and the potential coordination of the different processes, which will
ultimately yield to the formation of a late endosome, which can undergo fusion with a lysosome. I
will report on our recent progress in understanding the regulation of the flow through the endosomal
system.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 29
SESSION 1: GENE REGULATION
Stéphanie Debrulle
Selected
Oral
nication
Commu
Hidalgo-Figueroa M.1, Pelosi B.1, Baudouin C.1, Francius C.1,
Ronellenfitch K.2, Rucchin V.1, Tissir F.3, Chow R.L.2, Lee S.K.4 and Clotman F. 1
1 Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, Belgium
2 University of Victoria, Department of Biology, Victoria, Canada;
3 Université catholique de Louvain, Institute of Neuroscience, Laboratory of Developmental Neurobiology, Brussels, Belgium
4 Oregon Health & Science University, Portland, USA
Vsx1 secures the segregation of V2 interneuron versus
motor neuron identity during spinal cord development
L
ocomotion is a complex behavior regulated by neuronal circuits located in the ventral region of
the spinal cord. These circuits are constituted of motor neurons and different populations of
interneurons. Ventral interneurons mainly arise from 4 progenitor domains, namely p0-p3. The
p2 domain is described to produce 5 populations of interneurons: V2a, V2b, V2c, V2d and V2-Pax6.
We have recently identified an early V2 interneuron precursor compartment characterized by the
transient expression of the transcription factor Vsx1 in the mouse embryonic spinal cord (Francius
et al., 2016). This compartment, composed of cells that exited the cell cycle but did not initiate
neuronal differentiation, generates all the V2 interneuron populations. In this study, we investigated
the function of Vsx1 in this intermediate V2 compartment.
U
sing loss-of-function and gain-of-function experiments in the mouse, we demonstrate
that Vsx1 secures V2 interneuron identity by repressing motor neuron fate and possibly
promoting V2 differentiation. Indeed, ectopic expression of Vsx1 in motor neuron progenitors
inhibits motor neuron differentiation whereas increased production of Vsx1 in V2 cells stimulates
V2 differentiation. In contrast, absence of Vsx1 does not impact on V2 interneuron or motor neuron
development, suggesting possible redundancy with other regulators. Chx10, a V2a marker, is the
single paralog of Vsx1 in the mouse genome. As previously shown for Chx10, we demonstrate
that Vsx1 is able to bind a specific enhancer in the Hb9 gene that strongly contributes to motor
neuron differentiation and that Vsx1 inhibits activation of this enhancer by the motor-neuron
specific Isl1-NLI-Lhx3 complex. Hence, our data suggest that Vsx1 and Chx10 act sequentially to
secure V2 interneuron identity by preventing activation of the motor neuron differentiation in the V2
compartment and possibly promoting global V2 differentiation.
30 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 1: GENE REGULATION
Cristiana Dondi
Selected
Oral
nication
Commu
Benjamin Bertin, Krzysztof Jagla, Guillaume Junion
University of Clermont-Ferrand, France
Molecular and functional analysis of cardiac diversification by cell
specific genomic approaches
C
ardiac cells diversification is required for the formation of a functional heart. Human heart
is a multi-lineage organ obtained through progressive diversification of progenitors derived
from different heart fields. This process goes with numerous changes in the expression of a
repertory of genes that allow cells to acquire their own identity and functions. The goal of this project
is to identify the repertories of genes that control the formation of different types of cardiac cells by
applying technological developments involving whole genomic approaches in cell type resolution
that we can use in Drosophila model. The Drosophila embryo is a relatively simple model to study
the diversification of cardiac cells and their properties. Only three types of cardioblasts exist in
early embryogenesis and even after anteroposterior differentiation the various cell types are easily
identifiable. The project aims to identify the «translatome» specific to each type of cardiac cells and
the mechanisms of transcriptional and post-transcriptional regulation, basics of the process of heart
cells diversification.
T
o reach this objective we performed cell-specific translatomic analyses in two subsets of
Drosophila cardiac cells (Tinman (Tin) and Labybird (Lb) expressing cells), at two different
time windows. To address that, we applied the Translation Ribosome Affinity Purification
(TRAP) method following by RNA sequencing in order to identify mRNA engaged in translation
specific to each cardiac cell types, overtime.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 31
SESSION 2: CELL POLARITY & TRAFFIC
Florence Besse
Jeshlee Vijayakumar, Charlène Perrois, Caroline Medioni, Marjorie Heim,
Fabienne De Graeve, and Florence Besse
Selected
Oral
nication
Commu
Valrose Biology Institute (iBV),UCA, CNRS, Nice, France
Regulating neuronal RNA granules in space and time
E
ukaryotic cells contain large cytoplasmic RNP granules that contain RNAs and associated
regulatory proteins and are involved in the spatio-temporal regulation of transcript expression.
In neurons, so-called neuronal granules have been implicated in the long-distance transport of
mRNAs to axons or dendrites, and in their local translation in response to external cues. Although it
has become clear that the properties of these complexes are modulated in response to developmental
and environmental cues as well as aging, how such changes are achieved at the molecular and
cellular levels is currently poorly understood.
U
sing the fruitfly as a model organism, we have identified the conserved RNA binding protein
Imp as a component of neuronal RNP granules and have shown that its transport to axons
is tightly regulated during brain maturation. Furthermore, Imp function is essential for axonal
remodeling (Medioni et al., 2014). Our current work aims at understanding how neuronal RNP granules
are assembled, and how their properties and transport are regulated during development. Assembling
and maintaining such large complexes represents a challenge for cells, as RNP granule components
must first undergo a demixing reaction that segregates them from the soluble cytoplasmic fraction,
and then establish extremely dynamic interactions with each others. While defective demixing will
prevent the formation of RNA granules, alterations in RNA granule dynamics will generate static
pathological inclusions. To identify factors controlling RNA granule assembly and turnover, we are
combining different approaches including structure/function analyses, purification of RNP granules,
and high throughput microscopy-based RNAi screen. In particular, we have recently uncovered the
importance of prion-like domains in the regulation of RNA granules using FRAP and in vitro phase
transition assays, and have revealed their requirement for axonal transport and remodeling.
32 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Nicolas Chartier
Arghyadip Mukherjee2, Sebastian Fürthauer3, Frank Jülicher2, Stephan W Grill1
Selected
Oral
nication
Commu
1 Biotechnology Center, Technical University Dresden, Dresden, Germany .
2 Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.
3 New York University, Courant Institute of Mathematical Science New York City, USA
Biomechanical Control of Oocyte Growth in Caenorhabditis elegans
W
hile tissues are generally composed of individualized cells, the germline of many species
develops through incomplete cytokinesis to form a syncytium where germ cells (GCs) are
connected and share a common cytoplasm. Such syncytial structures could confer unique
biomechanical properties to tissues and participate directly in GCs functions, however, little is known
about the specific mechanics of syncytial tissues. In order to describe the biophysical properties of
germline syncytium and their implications in GCs growth, we use the gonad of Caenorhabditis elegans,
which comprises hundreds of GCs organized in a tubular monolayered syncytium. All GCs are open
on their apical side onto a central cytoplasmic core called rachis, where cytoplasm can flow and
participates in oocyte growth. To understand how the syncytial structure can be stable without any
volume conservation of individual GCs, we used highresolution confocal videomicroscopy coupled
with semi-automated quantification to build a continuous map of GCs volumes, densities, velocities
as well as cytoplasmic flow rates profiles. We show that GCs reach a stable optimal volume before
a sudden increase in volume variability corresponding to the zone where GCs are directed toward
two distinct fates: dying by apoptosis or growing as mature oocytes. We developed a theoretical
description suggesting that a mechanical instability could contribute to GCs apoptosis in this system
and that GCs stability could depend on tension applied on them by the rachis cortex. Quantification
of actomyosin regulators distribution and laser ablations experiments indicate that the rachis cortex
is indeed under active tension, which is distributed heterogeneously along the distal to proximal axis,
driving rachis closure proximally. Overall, our work provides novel information about the specific
biophysical properties of syncytial structures and their role in oocyte growth.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 33
SESSION 1: GENE REGULATION
Anna Mattout
A Mattout, D Gaidatzis, J Padeken, F Aeschimann and SM Gasser
Friedrich Miescher Institute for Biomedical Research,
affiliated with Basel University, Switzerland
Invited Speaker
A post-transcriptional mechanism specialized in silencing
H3K27me3 genomic regions in C.elegans
H
eterochromatin, correlates with repressed gene expression. Transcriptional repression is
believed to be the main - if not the only - mechanism responsible for the silencing of promoters
in heterochromatin in higher eukaryotes. However, in a genome-wide derepression screen of
a heterochromatic reporter, we identified unexpectedly three RNA binding proteins, members of the
LSM complexes. We examined their function in order to identify potential heterochromatin silencing
mechanisms at the co-/post-transcriptional level in metazoan. The C. elegans LSM proteins share 6090% homology with the human LSMs, and assemble into two major complexes, LSM1-7 and LSM28. The LSM1-7 is known primarily to be involved in cytoplasmic mRNA decay while LSM2-8 regulates
both nuclear mRNA decay and U6 snRNA stability. Combining microscopic, genetic and genomic
approaches we could show that LSM2-8 silences specifically heterochromatic reporters. Importantly,
the complex also silences endogenous regions selectively enriched for the heterochromatic mark
H3K27me3. Developmental defects and premature death were observed in worms lacking LSM8. LSM-8-mediated silencing is dependent on mes-2, the Polycomb-like HMT responsible for
H3K27me3 deposition, whereas it is independent of H3K9me2/me3. LSM-8-mediated silencing not
only depends on H3K27me3 but also appears to favor H3K27me3 deposition on the silenced genes.
LSM8-mediated silencing is detectable from early embryonic stages through adulthood, in every
somatic cells. Importantly, we also found that the LSM2-8 complex works cooperatively with XRN-2,
a 5’-3’ exonuclease. Together, our results suggest that the LSM2-8 complex recognize selectively
transcripts arising from heterochromatic H3K27me3-enriched domains and promote their silencing
through degradation by XRN-2. LSM8-mediated silencing of H3K27me3 genomic regions through
RNA silencing, is a new mechanism, at a new level of regulation, which was not previously shown for
higher eukaryotes.
34 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Richard Anderson
University of Wisconsin-Madison,
School of Medicine and Public Health, USA
Invited Speaker
Agonist-Stimulated Scaffolding of the full PI 3-kinase pathway
G
eneration of the lipid messenger phosphatidylinositol 3,4,5-trisphosphate (PI3,4,5P3) is
crucial for development, cell growth and survival, motility and becomes dysfunctional in many
diseases including cancers. We defined a mechanism for PI3,4,5P3 generation by scaffolded
phosphoinositide kinases. In this pathway class I phosphoinositide 3-kinase (PI3K) is assembled by
IQGAP1 with PI4KIIIα and PIPKIα, that sequentially generate PI3,4,5P3 from phosphatidylinositol. By
scaffolding these kinases into functional proximity, the PI4,5P2 generated is selectively used by PI3K
for PI3,4,5P3 generation, which then signals to PDK1 and Akt that are members of the same complex.
Significantly, multiple receptor types stimulate the assembly of this IQGAP1-PI3K signaling complex.
Blockade of IQGAP1 interaction with PIPKIα or PI3K inhibited PI3,4,5P3 generation and signaling, and
selectively diminished cancer cell survival, revealing a novel target for cancer chemotherapy
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 35
SESSION 1: GENE REGULATION
Pascale Gilardi-Hebenstreit
Elodie Thierion1,3, Johan Le Men1, Samuel Collombet1, Céline Hernandez1,
Fanny Coulpier1, Morgane Thomas-Chollier1, Daan Noordermeer2,
Patrick Charnay1 and Pascale Gilardi-Hebenstreit1
Selected
Oral
nication
Commu
École Normale Supérieure, PSL Research University, CNRSUMR8197, Inserm U1024,
Biology Institute - École Normale Supérieure (IBENS), Paris, France,
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS,
Paris Sud University, University Paris-Saclay, France
Krox20 hindbrain regulation incorporates multiple modes
of cooperation between cis-acting elements
D
evelopmental genes can harbour multiple transcriptional enhancers that act concomitantly to
achieve robust and precise spatiotemporal expression. However, the mechanisms underlying
cooperation between cis-acting elements are poorly documented, notably in vertebrates. To
provide insights into the mechanisms involved in the regulation of a vertebrate gene by multiple
enhancers during development, we investigated the case of the mouse Krox20/Egr2 gene for which
several hindbrain-specific enhancers have been identified. Krox20 encodes a transcription factor
required for the specification of two segments, rhombomeres (r) 3 and 5 of the developing hindbrain.
Elements B (in r5) and C (in r3 and r5) are active from the initiation of Krox20 expression while element
A (in r3 and r5) requires direct binding of the protein for its activity. By studying the deletion of element
A in the mouse genome, we have shown that Krox20 is directly autoregulated through this element.
Using a conditional knock-out mutation of element C, we show that, unexpectedly, this element is
not necessary for Krox20 initial expression in r3 but appears absolutely required for the maintenance
of Krox20 expression in this rhombomere. This activity involves a cooperation in cis with element A.
By investigations of chromatin organisation (4C, ATAC-Seq), we show that element C increases the
accessibility of element A located at a distance of 70kb. In conclusion, element C possesses a dual
activity: besides its classical enhancer function, it is also permanently required in cis to potentiate the
autoregulatory activity of element A. This work uncovers a novel, asymmetrical, long-range mode of
cooperation between cis-acting elements that might be essential to avoid promiscuous activation of
positive autoregulatory elements.
36 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 1: GENE REGULATION
Elena De Sena
Elena de Sena, Nathalie Rocques, Caroline Borday, Hugo Juraver-Geslin,
Harem Sabr, Karine Parrain, Albert Chesneau, Beatrice Durand
Selected
Oral
nication
Commu
Curie Institute, Université Paris Sud, INSERM U1021, CNRS UMR3347,
France (ES, NR, CB, HJG,HS,BD)
Paris-Saclay Institute of Neuroscience, CNRS, Paris-Sud University, Paris-Saclay
University, Orsay, France (KP, AC)
A new brake on Wnt/Bcatenin activity: from determination of the
Spemann Organizer to Establishment of nerual stem cell niches
T
he Spemann Organizer is the first signaling center to appear in the embryo. It influences
the size and shape of the neural plate. Currently, little is known on what limits its size. The
transcription factor Barhl2 controls the size of the axial organizer, derived from the Spemann
Organizer, disrupting the gradient of Shh and anti-BMP factors in the neural plate. We previously
showed that it promotes apoptosis and limits Wnt activity. Our results demonstrate that Barhl2 lossof-function compensates Mcl-1 deficiency in Xenopus laevis embryos, and that Mcl-1 promotes in
turn the Spemann organizer cells survival during gastrulation. At the blastula stage Barhl2 modifies
the expression levels of genes expressed in the Spemann Organizer: Barhl2 loss-of-function increases
the size of the Spemann Organizer whereas Barhl2 gain-of-function decreases it. We demonstrated
that Barhl2 recruits the Wnt pathway cofactor Groucho/TLE and along with the histone deacetylase
HDAC-1 they inhibit the Spemann organizer genes expression. This work produces a new insight in
the Groucho/TLE regulation and on the factors that give specificity to HDAC-1.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 37
SESSION 1: GENE REGULATION
Leiore Ajuria-Astobiza
Marilyne Duffraisse, Samir Merabet
Selected
Oral
nication
Commu
IFGL, UMR 5242 CNRS, École Normale Supérieure, Lyon, France
Specific interaction between Hox proteins and LaminC at
the nuclear periphery is required for developmental control
of autophagy in Drosophila
L
L
H
amins are the main components of the nuclear lamina, which form a protein meshwork
under the inner nuclear membrane. They play important roles in nuclear shape determination,
heterochromatin organization or cytoskeletal organization.
amina associated genes are often transcriptionally repressed. Cumulative data suggest that
this repression is achieved by recruiting chromatin modifiers and transcription factors to the
nuclear periphery, rendering the nuclear lamina highly hierarchical transcriptional regulator.
The molecular mechanisms underlying this regulation remain however poorly understood.
ere we show that autophagy repression by Hox proteins in the Drosophila larval fat body
depends on the interaction with the inner nuclear membrane protein LaminC. We describe
how this interaction is regulated in vivo and how it impinges in the temporal-specific
regulation of autophagy related (atg) genes. Our study constitutes the first molecular characterization
of a partnership between LaminC and a family of specific DNA-binding regulators during a key
developmental process.
38 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Nicolas Taulet
Benjamin Vitre, Christelle Anguille, Audrey Douanier, Murielle Rocancourt,
Arnaud Echard and Benedicte Delaval
Selected
Oral
nication
Commu
CRBM-CNRS UMR 5237, Montpellier, France
Pasteur Institute CNRS UMR 3691, Paris, France
IFT proteins spatially control symmetrical cleavage
furrow ingression and lumen positioning
C
ytokinesis mediates the physical separation of dividing cells. In 3D epithelia, it also provides
a spatial landmark for lumen formation. Cleavage furrow ingression in anaphase relies on
proper central spindle organization and requires the recruitment and activation at this site
of key cytokinetic regulators including the centralspindlin complex which controls the activation of
RhoA at the equatorial cortex. Here, we unravel an unexpected role in cytokinesis for proteins of
the intraflagellar transport (IFT) machinery, initially characterized for their function in cilia and their
link to polycystic kidney disease. Using 2D and 3D cultures of renal cells, we show that IFT proteins
are required to control symmetric cleavage furrow ingression and subsequent lumen positioning.
Mechanistically, we demonstrate that IFT are essential for the correct relocalization of the Aurora
B/MKLP2 complex to the central spindle, hence for proper centralspindlin distribution and central
spindle microtubules organization. This work thus unravels a novel, non-ciliary mechanism for IFT
proteins at the central spindle of dividing cells, which could contribute to kidney diseases by affecting
lumen positioning.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 39
SESSION 2: CELL POLARITY & TRAFFIC
Delphine Delacour
Salomon J 1,2, Gaston C 1, Magescas J 1, Schmitz J , Minc N 3,
Ladoux B 1,4, Goulet O 2 and Delacour D 1
Selected
Oral
nication
Commu
1 Cell Adhesion and Mechanics, Jacques Monod Institute, CNRS UMR7592, Paris Diderot University, Paris, France,
2 Paediatric Gastroenterology Department, Necker Hospital - Sick Children,
Sorbonne Paris Cité, Paris, France
3 Cellular spatial organization, Jacques Monod Institute, CNRS UMR7592, Paris Diderot University, Paris, France
4 Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
Contractile forces at tricellular contacts modulate
epithelial organization and monolayer integrity
T
he Congential Tufting Enteropathy (CTE), alternatively named Intestinal Epithelial Dysplasia,
is a rare human congenital enteropathy. In 73% of the CTE patients, the disease has been
associated with pathogenic loss of function mutations of the EPCAM gene coding for an
epithelial cell adhesion molecule. The CTE intestinal epithelium displays unique morphological
abnormalities, materialized by formation of aberrant focal stacks of pseudo-multilayered enterocytes
on the villus, named “tufts”. Here we characterize cellular defects related to EpCAM loss in intestinal
epithelium. The absence of EpCAM causes unusual cell organization defects, together with an
expansion of the apical membrane and the ectopic appearance of the brush border at tricellular
contacts. These abnormalities stem from an inappropriate actomyosin activity at tricellular contacts,
thus providing a new function for EpCAM in contractile force patterning in the epithelium. Actomyosin
clustering and excess of cortical forces at TCs generates local deformation of tight junctions and
displacement of tricellular proteins, which are easily reversed upon myosin activity inhibition.
At the tissue level, modifications of the contractile properties at tricellular contacts may be at the
origin of the development of tufts in CTE patients. We generated 3D elastomeric substrates that
mimic villous physical constraints. Tuft-like structures only appear on EpCAM-deprived synthetic villi,
testifying of an enhanced mechanical stress provided by the particular topography of the monolayer
substrate. EpCAM-deprived cells cultured on 3D synthetic villi can phenocopy CTE cellular and
tissue defects. Moreover, the alteration of epithelial contractile patterning is directly correlated to the
development of tissue lesions, since tissue-scale defects could be erased with contractility inhibitors.
In conclusion, EpCAM is required for the regulation of tension homeostasis within epithelial monolayer,
and the proper balance of cortical tension within epithelial tissues provides a link between tissue
integrity and intercellular adhesion.
40 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Ann Wehman
Jaime N. Lisack, Maurice Stetter, Gholamreza Fazeli
Selected
Oral
nication
Commu
Rudolf Virchow Center, University of Wuerzburg, Germany
The fate of the second polar body after extrusion
in C. elegans embryos
P
U
olar bodies containing maternal DNA are extruded to form a haploid oocyte, but their fate
is poorly understood. We study C. elegans polar bodies to understand how cells deal with
released vesicles containing potentially harmful cargos, such as extra chromosomes.
sing time-lapse imaging of fluorescent reporter strains and a panel of mutants, we found that
the second polar body is internalized in a stereotyped manner at the 2- or 4-cell stage. Prior
to internalization, actin and the phagocytic receptor CED-1/MEGF11 are enriched around
the polar body, consistent with the formation of a phagocytic cup. CED-1, CED-2/Crkl, and other
CED-10/Rac-dependent engulfment pathway proteins are required for polar body internalization,
indicating that the polar body is internalized via receptor-mediated phagocytosis similar to cell
corpse engulfment.
R
eceptor-mediated phagocytosis demonstrates that there is signaling between the polar
body and embryonic cells. This raises the possibility that the polar body has a function after
extrusion. We examined the pattern of inheritance of the polar body and did not observe a
link between polar body inheritance and cell fate. Thus, the polar body is unlikely to be a cell fate
determinant. We are currently testing whether polar body removal alters embryonic development.
A
fter polar body phagocytosis, the double membrane phagosome is decorated with RAB-5,
RAB-7, and the autophagy-associated Atg8/LC3 protein. Polar body degradation is delayed
when Atg8/LC3 lipidation is disrupted by atg-7 knockdown, but not when the macroautophagy-
specific PI3K subunit EPG-8 is deleted, suggesting that the polar body is degraded via LC3-associated
phagocytosis. Before degradation, the polar body phagosome fragments, a rare example of double
membrane budding. Thus, our observations of polar body trafficking establish a new model system
for studying the mechanisms of receptor-mediated phagocytosis, double membrane budding, and
degradation via LC3-associated phagocytosis
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 41
SESSION 1: GENE REGULATION
Alfonso Martinez-Arias
Department of Genetics, University of Cambridge,
Cambridge CB2 3EH, UK
Invited Speaker
Genetically supervised axial (self) organization in
aggregates of mouse embryonic stem cells
E
mbryonic Stem (ES) cells are clonal derivatives from the blastocysts of mammalian embryos
which have the potential to give rise to all lineages of the embryo and the ability to self renew
this ability. Mouse ES cells have proven an excellent system in which to study developmental
events, in particular the mechanisms of cell fate decisions. However, while it is easy to coax them
into elements of different tissues in culture, they do not organize themselves as they do in embryos.
Non adherent culture leads them to form aggregates in which some cell types appear in clusters but
there is no overall organization.
R
ecently we have developed a non adherent culture system in which small aggregates of mouse
ES cells undergo symmetry breaking, polarized gene expression and growth and gastrulation
like movements in vitro. Using a variety of reporter ES cell lines and comparison with the
embryo we observe organization of Wnt, Nodal and FGF signaling that mirrors events in the embryo
and have shown that they can develop in culture until an equivalent of embryonic day 9 (E9). We
observe that these embryonic organoids develop anteroposterior, dorsoventral as well as bilateral
asymmetries. Analysis of pattern formation in these aggregates suggests that they do not develop
through standard self organization but that there is a strong genetic components to what otherwise
would be simple thermodynamically driven process. These issues will be discussed in course of the
talk.
A
n important value of this organoid system is the ability to generate spatially organized niches
and we have used this system to study the emergence and dynamics of a stem/progenitor
population that gives rise to the spinal cord and the paraxial mesoderm.
42 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: CELL POLARITY & TRAFFIC
Wieland Huttner
Max Planck Institute of Molecular Cell Biology and Genetics,
Dresden, Germany
Invited Speaker
On the role of human-specific genes, notably ARHGAP11B,
in neural stem cell amplification and neocortex expansion
in development and human evolution
O
ur group studies neural stem and progenitor cells in the context of the expansion of the
neocortex in development and evolution. Two major classes of cortical stem/progenitor cells
can be distinguished. First, stem/progenitor cells that reside in the ventricular zone (VZ), i.e.
neuroepithelial cells, apical radial glia (aRG) and apical intermediate progenitors, collectively referred
to as apical progenitors (APs). Second, stem/progenitor cells that reside in the subventricular zone
(SVZ), i.e. basal radial glia (bRG) and basal intermediate progenitors, collectively referred to as basal
progenitors (BPs). Neocortex expansion is thought to be linked to an increased abundance and
proliferative capacity of BPs.
T
o gain insight into the genomic changes that underlie neocortex expansion, notably in
humans, we have analyzed the transcriptomes of human vs. mouse VZ and SVZ, and of
human vs. mouse aRG and bRG. This led to the identification of the human-specific gene
ARHGAP11B as a major player. Specifically, ARHGAP11B promotes the generation of BPs from aRG
and the subsequent BP proliferation, thereby increasing BP abundance. Moreover, ARHGAP11B is
able to induce folding of the embryonic mouse neocortex, which normally is smooth. The ability of
ARHGAP11B to amplify BPs is based on a single C-to-G base substitution which creates a novel
splice donor site; this leads to the removal of 55 nucleotides upon mRNA splicing, resulting in a
reading frame shift and generating a human-specific 47-amino acid sequence that is thought to be
key for BP amplification.
T
o compare neural stem cell division between human and great ape developing neocortex,
we have performed live imaging using iPSC-derived 3D cerebral organoids. This revealed a
specific lengthening of metaphase during AP mitosis in human as compared to chimpanzee
and orangutan. The potential implications of this metaphase lengthening will be discussed.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 43
44 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2 - FRIDAY 28th APRIL
SIGNALLING
FRIDAY 28th APRIL
09:00-11:45 am
Plenary Session 2: SIGNALLING
09:00-09:30 am
Invited Seminar: Eduardo Moreno
«Regulating the cellular composition of our bodies using
Fitness Fingerprints»
09:30-10:00 am
Invited Seminar: Catherine Rabouille
«Stress assemblies in the control of anabolic pathways»
10:00-10:30 am
Coffee break
10:30-10:45 am
Alvéole Presentation
10:45-11:00 am
MP Biomedicals Presentation
11:00-11:30 am
Invited Seminar: Benoît Ladoux
«Physical control of cell extrusion and death in epithelia»
11:30-12:00 am
2 selected short talks: Mélina Heuzé & Mohamad Ali Fawal
12:00-12:30 pm
Invited Seminar: Sylvie Schneider-Maunoury
«Primary cilia in forebrain morphogenesis»
12:30-03:30 pm
Lunch buffet and Poster Session 2
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 45
SESSION 2: SIGNALLING
Eduardo Moreno
Champalimaud Foundation, Lisboa, Portugal
Invited Speaker
Regulating the cellular composition
of our bodies using Fitness Fingerprints.
H
umans are able to detect fitness decay in colleagues by looking at the graying of the hair or
the wrinkles in their faces. Work from my laboratory in the last few years has shown that cells
can also detect fitness levels of neighboring cells using a molecular code. Those “fitness
fingerprints” (Rhiner et al., Dev.Cell, 2010; Merino et al., Curr. Biol., 2013) can be used to mediate
cell selection by recognizing and eliminating less fit cells during ageing (Merino et al., Cell, 2015),
regeneration (Moreno et al., Curr. Biol., 2015) and cancer (Levayer et al., Nature 2015).
46 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: SIGNALLING
Catherine Rabouille
1.Hubrecht Institute of the KNAW and UMC Utrecht, NL
2. Department of Cell biology, UMC Groningen, NL.
Invited Speaker
Stress assemblies in the control of anabolic pathways
C
ell compartmentalization is mediated by membrane bound organelles but also membraneless compartments, such as P-bodies in which many steps of RNA metabolism take place.
Interestingly, membrane-less assemblies also form in response to cellular stress. For
instance, the recently described Sec bodies form when Drosophila cells are starved of amino-acid.
They contain the components of the early secretory pathway (COPII subunits and Sec16) that are
stored and protected from degradation. Sec bodies are reversible and their formation is controlled by
the PARP16 dependent mono-ADP-ribosylation of Sec16.
M
embrane-less compartments are important for tissue development and cell homeostasis.
In my presentation, I will discuss the relationship between P-bodies and the translational
control of gurken mRNA in the Drosophila egg chamber. I will then present data on the role
of Sec bodies in Drosophila survival during starvation.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 47
SESSION 2: SIGNALLING
ALVÉOLE PRESENTATION
Pierre-Olivier Strale, PhD
Senior Scientist at Alvévole
Light-induced quantitative photopatterning of biomolecules
P
rinting of biomolecules on substrates has developed tremendously in the past few
years. The existing methods either rely on slow serial writing processes or on parallelized
photolithographic techniques where cumbersome mask alignment procedures usually impair
the ability to generate multi-protein patterns. We recently developed a new technology allowing for
high resolution multi protein photopatterning. This technology named “Light-Induced Molecular
Adsorption of Proteins (LIMAP)” is based on a water-soluble photo-initiator able to reverse the
antifouling property of polymer brushes when exposed to UV light. We developed a wide-field pattern
projection system based on a DMD coupled to a conventional microscope which permits to generate
arbitrary grayscale patterns of UV light at the micron scale. Interestingly, the density of adsorbed
molecules scales with the dose of UV light thus allowing the quantitative patterning of biomolecules.
The very low non specific background of biomolecules outside of the UV-exposed areas allows for the
sequential printing of multiple proteins without alignment procedures. Protein patterns ranging from
≈ 1µm up to 1 mm can be performed within seconds, as well as gradients of arbitrary shapes. The
range of applications of the LIMAP approach extends from the single molecule up to the multicellular
scale with an exquisite control over local protein density. We show that it can be used to generate
complex protein landscapes both in 2D and 3D useful to study protein-protein, cell-cell and cellmatrix interactions.
48 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: SIGNALLING
MP BIOMEDICALS PRESENTATION
Dr Veronique KARSTEN
Product Manager FastPrep & Molecular Biology | MP Biomedicals
MP
Biomedicals is a worldwide corporation committed to the development, manufacturing
and marketing of life science and diagnostics products. The company is dedicated to providing
scientists and researchers with the most innovative and highest quality tool, combined with superior
service to aid them in their quest for ground-breaking discovery and turning the hope for life-changing
solutions into a reality.
MP
Biomedicals offers a line of more than 55.000 life science research and diagnostic
products (in the field of Molecular Biology, Cell Biology, Immunology, Biochemicals, Rapid Diagnostic,
EIA/RIA Diagnostic, etc…) that support academic and government research institutions as well as
pharmaceutical and biotechnology companies.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 49
SESSION 2: SIGNALLING
Benoît Ladoux
1 Mechanobiology Institute, National University of Singapore,
T-Lab, 5A Engineering Drive 1, 117411, Singapore
2 Jacques Monod Institute (IJM), CNRS UMR 7592
& Paris Diderot University, Paris, France
Invited Speaker
Physical control of cell extrusion and death in epithelia
T
he control of tissue growth, which is a key to maintain the protective barrier function of the
epithelium, depends on the balance between cell division and cell extrusion rate. Cells are
pushed out of the monolayer, thus preventing accumulation of unnecessary or pathological
cells. The extrusion process can be triggered by apoptotic signaling, oncogenic transformation, and
overcrowding of cells. Despite the important links of cell extrusion to developmental, homeostatic and
pathological processes, including morphogenesis and cancer metastasis, its underlying mechanism
and connections to the intrinsic mechanical properties of the epithelium are largely unexplored. First,
by measuring the multi-cellular dynamics and traction forces, I will show that changes in epithelial
packing density lead to the emergence of distinct modes of cell extrusion. In confluent epithelia with
low cell density, cell extrusion is mainly driven by the lamellipodia-based crawling mechanism in
the neighbor non-dying cells in connection with large-scale collective movements. As cell density
increases, cell motion is shown to slow down and the role of a supra-cellular actomyosin cable
formation and its contraction in the neighboring cells becomes the preponderant mechanism to
locally promote cell extrusion.
T
hen, I will present how apoptotic cell extrusion is provoked by singularities in cell alignments
in the form of comet-like topological defects. We found a universal and robust correlation
between the extrusion sites and positions of comet-like, nematic defects in the cell orientation
field among several types of epithelium. By modeling the epithelial dynamics as an active nematic
liquid crystal and compare the numerical simulations to measurements of strain rate and stresses
within cell monolayers, we show that MDCK epithelial cells indeed behave as active nematic materials.
In addition, defect-induced isotropic stresses serve as the primary precursor of mechanotransductive
responses in cells as shown by YAP (Yes-associated protein) transcription factor activity, caspase-3
mediated cell death, and cell extrusions. Exploiting this defect-induced extrusion mechanism, we
further demonstrate the ability to control extrusion hotspots by geometrically inducing nematic
defects through microcontact-printing of patterned monolayers. Our model proposes a novel
mechanism for apoptotic cell extrusion where spontaneously formed topological defects in epithelial
monolayers govern cell fate.
50 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: SIGNALLING
Mélina Heuzé
Gautham Sankara, Tien N’guyen, Shreyansh Jain, David Williams,
Jan van Hest, Benoît Ladoux, René-Marc Mège
Selected
Oral
nication
Commu
Jacques Monod Institute, CNRS UMR7592, Paris, France
Understanding the role of Myosin II isoforms
in epithelial junction biogenesis
F
ormation and remodeling of adherens junctions are essential for many biological processes
like early embryo compaction, tissue morphogenesis, and wound healing. In epithelial cells,
nascent cell-cell adhesions induce the recruitment and clustering of E-cadherin molecules and
their downstream partners including acto-myosin cytoskeleton. Myosin II has been shown to act as
a mechanical support and force-generator for E-cadherin junctions during collective migration.
I
O
n this work, we investigate the role of Myosin II and its different isoforms during junction biogenesis,
using an in vitro reductionist approach. This in vitro system, based on chemically-switchable
micro-patterns, allows us to visualize early and transient events of single junction formation in a
controlled manner.
ur observations show that epithelial junction formation is a non-reversible process. Nascent
junctions appear very dynamic and support high local tension. During the first hours after
contact, we observe a complete repolarization of actin cytoskeleton and centrosome opposite
to the junction. Inhibition of Myosin II alters junction stability and prevents centrosome repolarization.
It also impacts E-cadherin enrichment and organization.
I
nterestingly, the two major Myosin II isoforms, MyoIIA and MyoIIB, show differential subcellular
localization, probably related to their different properties in actin binding and ATPase activity.
Whereas MyoIIA binds to contractile actin fibers parallel to the junction, MyoIIB colocalizes with
E-cadherin and junctional actin. Our preliminary observations following Myosin II isoform-specific
silencing indicate that MyoIIA and MyoIIB have complementary functions in junction biogenesis and
dynamics. Surprisingly, MyoIIB also associates to vimentin filaments throughout the cell body, which
opens new perspectives on the role of intermediate filaments in junction biogenesis.
O
ur study shows that Myosin II isoforms have complementary contributions to adherens
junction biogenesis. Ongoing work, using traction force microscopy approaches, aims at
determining their respective role in force transduction and resistance to force of cell-cell
adhesions.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 51
SESSION 2: SIGNALLING
Mohamad Ali FAWAL
Jungas Thomas, Audouard Christophe, Davy Alice
Selected
Oral
nication
Commu
CNRS UMR5547, Toulouse, France
Eph/ephrin signaling drives differentiation through
epigenetic remodeling of neural progenitors.
E
phrins and Eph receptors enable contact-mediated interactions between cells and participates
in a wide spectrum of developmental processes. At the cellular level, this transduction pathway
is best known for its role in the control of cell adhesion and repulsion, cell migration and
morphogenesis. Interestingly, a number of publications have also implicated Eph:ephrin signaling in
the control of adult and embryonic neurogenesis. Here we show that ephrin B1 stimulation of neural
progenitors leads to changes in both their differentiation and stemness potential. Moreover, we
noted these changes were transmitted to the daughter cells in the absence of stimulation indicating
a potential genomic reprograming. Interestingly, transcriptional and functional analysis of neural
progenitors stimulated by Ephin B1 showed an alteration in the folate pathway genes and activity. Our
data indicate that by regulating the folate metabolism, Eph/ephrin B signaling alters the methylation
state of H3K4 and lock neural progenitors in a differentiation-ready state. The identification of a
functional link between cell-cell communication pathway and metabolic reprograming reveals a
novel mechanism to control cell self-renewal and differentiation in the brain.
52 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 2: SIGNALLING
Sylvie Schneider-Maunoury
Alice Karam, Abraham Andreu, Guillaume Pezeron,
Isabelle Anselme, Christine Laclef, Martin Catala
Biology and Development Laboratory CNRS UMR7622,
Inserm U1156, Sorbonne Universities, UPMC, Paris, France.
Invited Speaker
Primary cilia in forebrain morphogenesis
I
n order to produce the correct numbers and types of neurons at the proper position during
development, the identity and behaviour of neural progenitor cells is tightly regulated in time and
space by a combination of external signals that control cell-intrinsic programmes. Accumulating
evidence implicates primary cilia, organelles that project from the cell surface, in the reception and
interpretation of these signals (1). Consistent with the broad distribution and multiple functions of
cilia, a large group of human diseases, termed ciliopathies, has been linked to their dysfunction.
Ciliopathies display neural defects ranging from intellectual disability to anencephaly (2). Further and
more systematic analysis is essential to better understand the developmental origin of these brain
defects.
O
ur lab has reported mutations in the human FTM/RPGRIP1L gene in two severe ciliopathies
with associated brain abnormalities (3). The Ftm protein is found at the base of primary cilia
and is required for ciliogenesis in neural progenitor cells. Ftm knock-out mice die around birth
and show multiple forebrain defects, including agenesis of the olfactory bulbs and corpus callosum,
two defects reported in severe ciliopathies (3). The FtmKO mouse line is thus a good model to study
the physiopathology of these diseases.
U
sing this mutant line, we have previously demonstrated that Ftm is involved in telencephalic
patterning by mediating the production of the repressor form of Gli3, an effector of the
Hedgehog signalling pathway (4,5). Our recent analysis of the diencephalon and hypothalamus
of Ftm mutants shows a loss of ventral structures, completing the picture of cilia function in
forebrain patterning. Moreover, our study of the cerebral cortex shows that Ftm and primary cilia play
a dual role, both Gli dependent and Gli-independent, in progenitor proliferation and neurogenesis.
Altogether, our data highlight the spatiotemporal diversity of the functions of primary cilia in forebrain
morphogenesis and signalling. The relevance of these studies for understanding the developmental
origin of brain defects found in human ciliopathies will be discussed.
1) Goetz & Anderson. 2010. Nat Rev Genet 11, 331. 2) Han & Alvarez-Buylla. 2010. Curr Opin Neurobiol 20, 58.
3) Delous et al. 2007. Nature Genetics, 39 p. 875-81. 4) Besse et al. 2011 Development 138:2079-88. 5) Laclef
et al. 2015. Hum Mol Genet. 24:4997-5014.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 53
54 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 3 & 4 - FRIDAY 28th APRIL
•EMERGENT MODELS & EVOLUTION
•CELL MIGRATION & ADHESION
FRIDAY 28th APRIL
03:30-06:15 pm In Parallel:
Sessions 3: EMERGENT MODELS & EVOLUTION AND 4: CELL MIGRATION & ADHESION
03:30-04.00 pm
Invited Seminar
- Session 3: Nipam Patel
«The Evolution of Arthropod Body Patterning:
Insights from Genome Editing in the Crustacean, Parhyale»
- Session 4: Pierre-François Lenne
«Shaping cell contacts during tissue morphogenesis»
04:00-04:30 pm
2 selected short talks / Session:
• Session 3: Cyril Basquin & Marco Grillo
• Session 4: François Fagotto & Fabiana Cerqueira-Campos
04:30-05:00 pm
Coffee break
05:00-05:30 pm
Invited Seminar
- Session 3: Patrick Lemaire
«Embryonic inductions may constrain the evolution
of ascidian embryonic morphogenesis»
- Session 4: David Sherwood
«Mechanistic insights into cell invasion:
Lessons from the C. elegans anchor cell»
05:30-06:00 pm
2 selected short talks / Session:
• Session 3: Abderrahman Khila & Frank Schnorrer
• Session 4: Anne Pora & Sandrine Etienne-Manneville
06:00-06:30 pm
Invited Seminar: François Payre
06:30-06:50 pm
SFBD Thesis Price
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 55
SESSION 3: EMERGENT MODELS & EVOLUTION
Nipam Patel
UC Berkeley, USA
Invited Speaker
The Evolution of Arthropod Body Patterning: Insights from
Genome Editing in the Crustacean, Parhyale
H
ox gene expression has been analyzed in a wide variety of arthropods, and this has led to
various hypotheses regarding the role of these genes in patterning the body plan. In addition,
changes in Hox gene expression between species has been postulated to play a role in the
evolutionary diversification of several animal groups. I will describe our comprehensive analysis
of Hox gene expression in the amphipod crustacean, Parhyale hawaiensis, and more importantly,
our results from using CRISPR/Cas9 gene editing to functionally address the role of Hox genes
in development. Finally, I will describe how this experimental data leads to some new views on
the evolution of the crustacean body plan, and how CRISPR/Cas9 genome editing can be used to
address these evolutionary hypotheses and other questions in a range of arthropod species.
56 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 4: CELL MIGRATION & ADHESION
Pierre-François Lenne
IBDM, Aix-Marseille University, France
Invited Speaker
Shaping cell contacts during tissue morphogenesis
T
he shaping of tissues and organs relies on the ability of cells to adhere together and deform
in a coordinated manner. It is therefore key to understand how cell-generated forces produce
cell shape changes and how such forces transmit through a group of adhesive cells in vivo.
We have recently studied how transient forces generated by Myosin II convert into irreversible cell
shape changes during epithelial morphogenesis. We show that viscoelastic dissipation is key to this
process. We will discuss how we measure this property and how it can guide tissue morphogenesis.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 57
SESSION 3: EMERGENT MODELS & EVOLUTION
Cyril Basquin
Anne-Marie Orfila, Pierre Le Gars, Noémie Gaudin, Juliette Azimzadeh
Selected
Oral
nication
Commu
Jacques Monod Institute, CNRS UMR7592, Paris, France
Identification of conserved centriole components controlling
centriole rotational polarity in multiciliated cells
M
ulticiliated cells form hundreds of motile cilia that beat in a coordinated fashion to generate
a fluid flow or displace particles and cells. To generate a directional fluid flow, cilia must
beat in a specific orientation with respect to the plane of the epithelium. Beating orientation
depends on the orientation within the plane of the plasma membrane of centrioles, from which cilia
are assembled. Planarian flatworms, best known for their extraordinary regeneration capacity, use
multiciliated cells for locomotion. Screening for genes affecting planarian locomotion, we identified
specific centriole orientation factors connecting centriole structure to tissue polarity. Whereas wild
type planarians move straight ahead, Smed-odf2(RNAi) flatworms move sideways to the right, and
Smed-vfl1(RNAi) and Smed-vfl3(RNAi) move sideways to the left. We analysed centriole rotational
polarity in planarians by staining the striated rootlet, a structure pointing opposite to ciliary beat.
In control planarians, ciliary beat is aligned with the anterior-posterior axis in the region of the
midline and progressively deviates from this axis toward the lateral edges. Thus, centriole rotational
polarity varies along the medio-lateral axis to form a bilaterally symmetrical pattern of orientation.
Following depletion of our candidate genes, abnormal direction of locomotion is correlated to defects
in centriole rotational polarity. Our results suggest a model in which centriole orientation results
from counterbalancing forces acting on the centrioles. The bilaterally symmetrical arrangement of
centrioles across the ventral epidermis results from the complex regulation of cytoskeletal arrays
that are intrinsically asymmetrical along the medio-lateral axis.
58 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 3: EMERGENT MODELS & EVOLUTION
Marco Grillo
Michalis Averof
Selected
Oral
nication
Commu
Institute of Functional Genomics, Lyon, France
Unraveling complex organ regeneration using a crustacean model
M
any animals have the ability to regenerate body parts that are lost through injury.
Regeneration restores both the number and the diversity of cells of the lost tissue, by
mobilizing specific populations of progenitor cells. It also restores pattern, giving rise to
well-proportioned and functional organs that are virtually indistinguishable from those of unharmed
animals.
I
n spite of great medical and biological interest, the molecular and cellular mechanisms underlying
this process are still not fully understood. Although specific progenitor cells have been identified
in some contexts, limited progress has been made in understanding the actual mechanisms of
regeneration. Part of the problem in identifying these mechanisms has been the lack of appropriate
tools that would allow us to visualize cell behaviour in a live regenerating organ.
O
ur lab set out the crustacean Parhyale hawaiensis as a tractable model for the study of the
cellular basis of regeneration. Our recent work has focused on establishing new genetic tools
and live imaging approaches for this crustacean, with a particular emphasis on different
aspects of limb regeneration following amputation.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 59
SESSION 4: CELL MIGRATION & ADHESION
François Fagotto
Selected
Oral
nication
Commu
Francois Fagotto, Laura Canty, Eleyine Zarour, Leily Kashkooli, Paul Francois
CRBM-CNRS, University of Montpellier, France
McGill University, Montreal, Canada
Embryonic boundaries do not rely on differential adhesion
nor differential tension but on local repulsion at the tissue interface
P
hysical separation of embryonic cell populations is fundamental to metazoan development.
The process, which results in the sharp delimitation of cell masses by so-called tissue
boundaries, appears to rely on the ability of individual cells to distinguish between homotypic
contacts, i.e. contacts with cells of the same type, and heterotypic contacts with cells of a different
type.
T
he cellular basis of this phenomenon has remained unclear and highly controversial. While
classical hypotheses assumed differences in adhesiveness or cortical contractility, we
demonstrated that Xenopus embryonic boundaries are produced through ephrin-Eph-based
repulsion, which generates high tension at heterotypic contacts. Contrary to common assumptions,
adhesive and contractile differences turned out to be surprisingly inefficient at inducing cell sorting
or even maintaining tissue separation.
C
omputer simulations supported and generalized these results, showing that high tension
at heterotypic contacts between two cell types is required for their segregation. Our results
support a model where separation does not rely on global physical differences between the
tissues, but on the establishment of a sharp discontinuity at the tissue interface.
60 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 4: CELL MIGRATION & ADHESION
Fabiana Cerqueira-Campos
Selected
Oral
nication
Commu
Cornelia Fritsch, Corinne Lours-Calet, Hervé Alegot, Olivier Bardot,
Pierre Pouchin and Vincent Mirouse
GReD CNRS UMR 6293 INSERM U1103 Clermont University, France
Dystrophin and Dystroglycan organize F-actin and
extracellular matrix during tissue morphogenesis
T
he elongation of the Drosophila ovarian follicle offers a nice model of tissue morphogenesis
involving the extracellular matrix (ECM). Following a fat2-dependent planar polarization of
the basal domain of the epithelial follicular cells, follicles undergo rotations that allow the
polarized secretion of ECM fibrils and participate in the orientation of F-actin stress fibers. ECM
fibrils and stress fibers are proposed to act as a molecular corset, constraining the medio-lateral
growth of the follicle and so promoting its elongation. However, the relationships between these
fibrils and stress fibers are unclear. We found that Dystrophin (Dys) and Dystroglycan (Dg), which
form a transmembrane complex interacting with F-actin and ECM, are involved in follicle elongation.
They are not required for rotation but for ECM fibril deposition. Moreover, they also orient in a cell
autonomous manner F-actin fibers, and this latter function is redundant with rotation during early
stages. Nonetheless, this function also relies on the previous ECM fibril deposition, indicating two
successive and interdependent functions of Dys/Dg complex. Together, our data show Dys/Dg
complex works as a critical organizer of the basal domain of the cells, acting on both F-actin and
ECM, and suggest that ECM fibrils act as a template for F-actin fiber orientation.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 61
SESSION 3: EMERGENT MODELS & EVOLUTION
Patrick Lemaire
Léo Guignard1,2*, Ulla Maj-Fiuza1*✝,
Emmanuel Faure2,3,4, Lars Hufnagel 5,
Grégoire Malandain 6, Christophe Godin 2# and Patrick Lemaire1#
Invited Speaker
1 CRBM, UMR5237, CNRS-U. Montpellier, France
2 Inria project-team Virtual Plants, joint with CIRAD and INRA,
Campus St Priest, Montpellier, France
3 Team VORTEX, Institute For Research in Computer Science (IRIT, UMR 5505, CNRS-INPT-Toulouse Universities I and III), France
4 Computational Biology Institute, Montpellier, France
5 EMBL, Meyerhofstrasse 1, Heidelberg, Germany
6 Inria project-team Morpheme, Sophia Antipolis, France
* Equal contribution and #: Equal contribution and corresponding authors
Embryonic inductions may constrain the evolution
of ascidian embryonic morphogenesis
A
small fraction of animal embryos, including the nematode Caenorhabditis elegans and
the ascidian Phallusia mammillata, develop with an invariant, stereotyped pattern of cell
divisions. Using light-sheet microscopy and automated 4D cell segmentation and tracking,
we constructed a whole-embryo atlas of P. mammillata cell behaviors between the 64-cell and initial
tailbud stages. This geometric description of embryogenesis tracks the positions, shapes and cell
contacts of each of 1304 cells with a 2-minutes temporal resolution and across 671 cell divisions.
Quantitative analysis of this geometric atlas confirms the bilaterality and high level of stereotypy
of ascidian embryos, and was sufficient to systematically identify fate restriction events up to the
end of gastrulation. We found that most fate restriction events identified are associated with either
unequal mother cell divisions, or distinct lifespans of daughter cells, providing temporal boundaries
for the cues driving fate restriction. These cues could be provided by juxtacrine cell inductions, whose
success depends on the area of contacts between inducing and induced cells. Finally, we show that
temporally and spatially scattered juxtacrine inductions impose geometrical constraints on nearly
all embryonic cells, which could explain the high level of geometric stereotypy of ascidian embryos.
62 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 4: CELL MIGRATION & ADHESION
David Sherwood
Department of Biology, Duke University, Durham, NC, USA
Invited Speaker
Mechanistic insights into cell invasion:
Lessons from the C. elegans anchor cell
T
I
he ability of cells to traffic through basement membrane barriers and enter neighboring
tissues, a process termed cell invasion, is crucial in many developmental processes and
cancer. Despite its importance, the mechanisms that control invasion are poorly understood,
largely due to the inability to visualize and experimentally examine this dynamic process in vivo.
will discuss work in my lab that uses live cell imaging and genetic analysis in C. elegans to reveal
fundamental mechanisms underlying cell invasive behavior. By examining anchor cell invasion, a
cell invasion event that connects the developing uterine and vulval tissues, we have found a new
cellular structure derived from rapid exocytosis of the endolysosome that is used to breach basement
membrane barriers and enter tissues. I will also present unexpected results on the dispensable
role of matrix metalloproteinases (MMPs) in tissue invasion, findings that might explain why MMP
inhibitor trials targeting cancer metastasis have been unsuccessful.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 63
SESSION 3: EMERGENT MODELS & EVOLUTION
Adberrahman Khila
IGFL, École Normale Supérieure, Lyon, France
Functional Genomics Institute, CNRS-UMR5242,
Ecole Normale Supérieure, Claude Bernard University, Lyon, France
Selected
Oral
nication
Commu
Water walking insects as emerging models
for integrating development, ecology and evolution
A
cquisition of new ecological opportunities is a major driver of adaptation and ultimately
speciation1,2. However, the selective pressures in play and how they interact with
developmental genetic pathways in shaping adaptive traits are often unknown. Water striders
(Heteroptera, Gerromorpha) have conquered water surfaces and diversified to occupy various niches
including ponds, streams and even oceans3,4. Paramount to their success in this new habitat are
adaptive changes in the shape and size of their legs, which fulfill a range of functions on the fluid
water-air interface including locomotion, prey-predator, and sexual interactions5-8. In this talk, we
will expose the large range of adaptive phenotypes that are directly associated with the new life style
that characterises water striders. We will show how various types of genetic changes, from gene
regulation to the emergence of novel gene content, have been instrumental for the development
and evolution of such traits. This presentation will introduce concrete examples of how the interplay
between ultimate ecological forces and developmental genetic processes can drive adaptive
evolution.
References:
1 Darwin, C. On the origin of species by means of natural selection, or, The preservation of favoured
races in the struggle for life. (J. Murray, 1859).
2 Schluter, D. The ecology of adaptive radiation. (Oxford University Press, 2000).
3 Andersen, N. M. & Cheng, L. The marine insect Halobates (Heteroptera : Gerridae): Biology, adaptations,
distribution, and phylogeny. Oceanogr Mar Biol 42, 119-179, doi:Book_Doi 10.1201/9780203507810
(2004).
4 Ikawa, T., Okabe, H. & Cheng, L. N. Skaters of the seas - comparative ecology of nearshore and
pelagic Halobates species (Hemiptera: Gerridae), with special reference to Japanese species. Mar
Biol Res 8, 915-936, doi:Doi 10.1080/17451000.2012.705848 (2012).
5 Andersen, N. M. A comparative study of locomotion on the water surface in semiaquatic bugs
(Insecta, Hemiptera, Gerromorpha). Vidensk. Meddr dansknaturh. Foren., 337-396 (1976).
6 Andersen, N. M. The semiaquatic bugs (Hemiptera: Gerromorpha). Vol. - Entomonograph Vol. 3.
(Scandinavian Science Press LTD., 1982).
7 Hu, D. L., Chan, B. & Bush, J. W. The hydrodynamics of water strider locomotion. Nature 42
64 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 3: EMERGENT MODELS & EVOLUTION
Frank Schnorrer
Sandra B Lemke, Carsten Grashoff
Selected
Oral
nication
Commu
IBDM - Developmental Biology Institute of Marseille, France
Max Planck Institute of Biochemistry, Martinsried, Germany
Measuring molecular tension at developing muscle attachment sites
D
uring muscle development, muscle cells establish integrin-mediated attachments to tendon
cells that allow the generation of mechanical tension across developing muscle fibers. This
tension has been demonstrated to be important for myofibrillogenesis and the formation
of regularly spaced sarcomeres within myofibrils. However, to date, tension at the molecular level
cannot be directly measured in the living organism during muscle development.
T
herefore, we adapted a Förster resonance energy transfer (FRET)-based tension sensor from
cell culture and introduced it into the Drosophila genome by CRISPR/Cas9-mediated genome
editing. By inserting the tension sensor module into the endogenous locus of the integrin
adaptor protein Talin, that localizes to muscle attachment sites, we ensure proper expression levels
and timing in all tissues, including the indirect flight muscles. The flies generated this way are viable
and able to fly, showing that the Talin tension sensor fusion protein is fully functional and allows the
flight muscles to work properly.
W
e established a protocol for fluorescence lifetime imaging (FLIM) and data analysis, which
enables us to measure FRET in a reproducible manner in developing muscles of living
pupae. We tested three different sensor modules to identify the best-suited sensor for
the range of forces present in the muscle tendon system. We then applied this sensor to determine
how molecular tension across Talin at muscle attachment sites changes during muscle attachment
formation and maturation, the latter coinciding with myofibrillogenesis, in the living organism.
W
e are now quantifying the effects of genetic perturbations on tension levels and
myofibrillogenesis during muscle development. Together, this allows us to study how
force is transduced molecularly at muscle attachment sites, and thus provides insights
into the molecular mechanism how tension build-up and myofibrillogenesis are functionally linked
during muscle morphogenesis.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 65
SESSION 4: CELL MIGRATION & ADHESION
Anne Pora
Bernd Hoffmann, Rudolf Merkel, Reinhard Windoffer, Rudolf E. Leube
Selected
Oral
nication
Commu
Institute of Complex Systems ICS-7 Biomechanics, Forschungszentrum Jülich, Germany
(Hoffmann and Merkel); Institute for Molecular and Cellular Anatomy, Uniklinik RWTH
Aachen, Germany (Windoffer and Leube)
Impact of the mechanophysical environment
on keratin network organization in migrating cells
C
ell migration is a highly complex process whereby different physical and chemical signals act
on many different cell components, most notably the force-generating cytoskeleton.
Intermediate filaments are one of the three major components of the cytoskeleton. Keratin
intermediate filaments are the main type of cytoplasmic intermediate filaments of epithelial cells.
They are anchored to hemidesmosomes which are involved in the attachment of epithelial cells to
the extracellular matrix of the basement membrane. Although keratin intermediate filaments are
involved in the mechanical resilience of tissues, they are highly dynamic structures. They are subject
to continuous turnover in sessile keratinocytes. This turnover is part of a spatially-defined cycle of
assembly and disassembly.
We aim at understanding how the dynamic behavior of the epithelial keratin intermediate filament
cytoskeleton and its associated hemidesmosomes are integrated in migrating cells and influenced
by the mechanical characteristics of the environment.
We demonstrate that matrix stiffness influences cell morphology and observe that keratin network
dynamics are increased in migrating cells. We also observe that keratinocytes have a higher migration
speed and persistence on soft matrices as was previously reported for other cell types. On such soft
matrices keratin cycling is faster. We also show that hemidesmosomal components are organized
in highly specialized patterns in migrating cells. Using traction force microscopy, we measure the
forces that adhesion sites apply on the matrix. We determine how keratin dynamics are affected
when a unidirectional stretch is applied to the matrix. Finally we examine the effects of confinement
in a microchannel and compare this to the restriction imposed by micro-patterned stripes that are
generated by deep-UV micropatterning.
Taken together, our findings show that the mechanophysical matrix properties impact keratin network
dynamics and suggest that the underlying cross-talk is important for epithelial cell migration as it
occurs in wound healing and tumor invasion.
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SESSION 4: CELL MIGRATION & ADHESION
Sandrine Etienne-Manneville
Pasteur Institute, CNRS, France
Selected
Oral
nication
Commu
Intermediate filaments control traction forces
during directed cell migration
C
ell migration requires dramatic and coordinate d reorganization of the different elements
of the cytoplasmic cytoskeleton.The cytoskeleton is mainly composed of three types of
filamentous structures; actin microfilaments, microtubules and intermediate filaments (IFs).
Actin structures are crucial for membrane protrusion, and cell adhesion and contractility and play a
well-characterized role in cell motility. Evidence has also emerged demonstrating the involvement of
microtubules in cell polarization and migration. However, little is known about the role and regulation
of the IFs network during cell migration. Qualitative and quantitative description of cytoskeletal
rearrangements are required to decipher the molecular mechanisms that specifically control the
changes in actin, microtubule and IF organization in migrating cells. Using primary astrocytes, we
have previously shown that IFs contribute to cell migration by affecting both cell protrusion, and
nucleokinesis. Wound-healing assay allows to induce cell polarization and to initiate directed migration
under controlled conditions. Wounding of an astrocyte monolayer induces profound rearrangements
of IFs in the wound edge cells. IFs elongate along microtubules in the direction of migration. IF
rearrangements rely on actin dynamics, microtubule-driven transport and microtubule associated
proteins. Using the combination of cutting edge quantitative microscopy techniques, we show that
a wound-induced signalling cascade locally induces the differential regulation of anterograde and
retrograde transport to promote the polarization of the IF network along the axis of migration.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 67
François Payre
Centre de Biologie du Développement, Toulouse, France
Invited Speaker
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2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 69
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SESSION 3 - SATURDAY 29th APRIL
MORPHOGENESIS & ORGANOGENESIS
SATURDAY 29th APRIL
09:00-11:45 am
Plenary Session 3: MORPHOGENESIS & ORGANOGENESIS
09:00-09:30 am
Invited Seminar: Renata Basto
«Spindle morphology tailoring trough time:
Differences in spindle architecture during mouse neurogenesis»
09:30-10:00 am
Invited Seminar: Jordi Casanova
«Progenitor cells and cell migration in Drosophila morphogenesis»
10:00-10:30 am
Coffee break
10:30-11:00 am
Invited Seminar: Christophe Marcelle
«A novel role for TGFβ signaling in regulating muscle cell fusion»
11:00-11:30 am
2 selected short talks: Mathilde Dumond & Bertrand Benazeraf
11:30-12:30 pm
Keynote Seminar - Olivier Pourquié
«Excitable dynamics of the segmentation clock»
12:30-12:45 pm
Concluding remarks and departure
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 71
SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Renata Basto
Diana Vargas-Hurtado, Carole Pennetier ,
Veronique Marthiens* and Renata Basto*
Biology of centrosomes and cilia UMR 144,
Curie Institute, Paris-France
Invited Speaker
Spindle morphology tailoring trough time:
Differences in spindle architecture during mouse neurogenesis
D
uring mitosis, the bipolar spindle, a highly dynamic microtubule-based structure ensures
accurate chromosome segregation. Centrosomes, the main microtubule-organizing
centers (MTOCs) of animal cells, organize the spindle poles contributing to its bipolarity.
Interplay between centrosomes, spindle and associated proteins influence the fidelity of each cell
division. Chromosome number deviations (known as aneuploidy) can influence cellular fitness and
performance and impair cell proliferation in certain contexts.
T
he mammalian brain is a unique organ as high levels of aneuploidy have been reported in
physiological conditions. However, when induced trough mutations in centrosome related
genes, aneuploid cells are efficiently eliminated leading to severe brain size reduction (or
microcephaly). Indeed, we have shown that the presence of supernumerary centrosomes, or
centrosome amplification, leads to chromosome segregation defects impairing embryonic neural
stem cell (NSC) survival in the mouse developing brain. Moreover, we found a higher susceptibility to
mitotic errors and cell death at early stages of development compare to late. The origin of this early
susceptibility is not known.
I
n order to characterize the cause of error-prone mitosis in the early neuroepithelium, we have
characterized mitotic spindle assembly during mouse neurogenesis in the WT brains. Strikingly,
we have found that the morphology of the mitotic spindle changes between early and late
neurogenic stages. While at early stages spindles of NSCs contain longer astral microtubules (MTs)
that contact the cell cortex, spindles at later stages present longer and thicker k-fibers (kinetochore
MTs) appearing more robust. Moreover, a comparative immunofluorescence analysis showed that
the distribution and levels of key spindle associated proteins such as Tpx2, Eg5, Tacc3, Aurora A and
NuMA were also varying between developmental stages.
O
verall, our results indicate unexpected modifications in the pathways used by NSCs to build
a bipolar spindle at different stages of neurogenesis. Such modifications might not only
explain why at early neurogenesis NSCs with centrosome amplification are more prone to
divide abnormally than at later stages but also what is at the origin of the marked susceptibility to
aneuploidy in the mammalian brain.
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SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Jordi Casanova
IBMB CSIC, IRB Barcelona, Spain
Invited Speaker
Progenitor cells and cell migration in Drosophila morphogenesis
C
ell migration plays a fundamental role in development and homeostasis. This event is very
often associated with static cells acquiring migratory capacity and becoming motile at very
precise times and settings. This behaviour is one of the most characteristic examples of
the epithelial cell plasticity. Not surprisingly, inappropriate migration is often associated with many
pathological conditions. Another case of cell plasticity lies at the base of organs’ ability to maintain
their structure and function in spite of natural or accidental cell loss. This capacity is often sustained
by the so-called stem cells; in addition, some specialized cells, known as facultative stem cells, also
retain the ability to re-enter the cell cycle and replace lost tissue. We are studying these phenomena
of cell plasticity in the context of the whole organism taking advantage of the Drosophila model and
I will present the results of our lab in cell plasticity in the morphogenesis of the Drosophila digestive
and tracheal (respiratory) systems.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 73
SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Christophe Marcelle
Christophe Marcelle 1, 2, Valérie Morin 1, Daniel Sieiro 1,2
1. NeuroMyoGène Institute, INMG, University Lyon1,
Faculty of Medicine Laënnec, Lyon, France
2. EMBL Australia, Australian Regenerative Medicine Institute,
Monash University, 15 Innovation Walk, Clayton VIC 3800, Australia.
Invited Speaker
A novel role for TGFβ signaling in regulating muscle cell fusion
M
uscle cell fusion is a key step of muscle growth, repair and regeneration, yet surprisingly
little is known on the cellular and molecular mechanisms regulating this process. Much
of the knowledge acquired to date on muscle fusion derives from genetic approaches
conducted in Drosophila. However, the result of decades of research in the field is a fragmentary
picture of the molecular machinery essential for fusion, disproportionately centered on actin and its
regulators.
O
ur team recently performed the first analysis of muscle cell fusion during vertebrate
embryogenesis, using the chicken embryo as model and double-electroporation protocols
(Sieiro-Mosti et al., Development 2014). This analysis uncovered that distinct muscle cell
populations, each competent to fuse, choose their fusion partners, fuse at different rates, and with
distinct spatial requirements, suggesting that fusion is regulated at two distinct levels: the first
determines whether cells are competent to fuse and encompasses the molecules identified in
invertebrates, mentioned above. The second orchestrates whether the fusion of two cells competent
to fuse is permitted, at which speed, etc. As of yet, nothing is known on the regulating factors that
regulate the second level of this process.
W
e performed a genome-wide RNA interference functional screen on a mouse C2C12
skeletal muscle cell line that identified a large number of candidate genes that significantly
activated or inhibited muscle fusion, with no effect on their differentiation or proliferation.
Because TGFβ family members were very strongly over-represented within this group, we decided
to test their function during muscle fusion in the chicken embryo. Our results suggest that TGFβ
signaling regulates the pace of muscle cell fusion during development.
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SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Mathilde Dumond
O Hamant, A Boudaoud
Selected
Oral
nication
Commu
Reproduction and Development of Plants Laboratory
CNRS UMR 5667, INRA, UCBL, ENS, Lyon, France
From variability to reproducibility: the role of mechanics
in the robustness of organ shape
H
ow organs shape and size are determined is still poorly understood despite much progress
in developmental genetics. Strikingly, organs have a reproducible shape while their cells have
a highly variable behavior [1,2]. How is such cellular variability buffered at the organ level? To
answer this question, we chose to study Arabidopsis thaliana sepal, because each plant has a large
number of almost identical sepals, which are accessible to live imaging. Moreover, giant cells are
produced stochastically in sepals [1] leading to a highly variable cell population. We addressed the
robustness of sepal shape using a combination of experiments and modelling.
I
n plants, morphogenesis is driven by internal hydrostatic pressure and controlled through the
regulation of cell wall properties. Therefore, we built a model of sepal morphogenesis that only
include these two parameters, and in which the impact of heterogeneity in mechanical properties on
final shape can be tested. To calibrate the extent of mechanical heterogeneity, we then measured cell
wall stiffness using atomic force microscopy. Stiffness appeared highly variable at both subcellular
and supracellular scales. We incorporated this level of variability in the model, which caused the loss
of shape robustness, as expected. In order to retrieve robustness of shape, we then had to introduce
temporal variability in stiffness in addition to spatial variability.
N
ext, we used this model to understand the phenotype of the vos1 mutant displaying low sepal
shape robustness [3]. In vos1 sepals, reactive oxygen species accumulate, causing premature
cell ageing and the reduction of the variability between neighboring cells. Combining analyses
of the mutant and model modifications, we reached the counterintuitive conclusion that increased
spatial heterogenetiy yields robust shapes.
References
[1] Roeder, A. H., Chickarmane, V., Cunha, A., Obara, B., Manjunath, B. S., & Meyerowitz, E.
M. (2010). Variability in the control of cell division underlies sepal patterning in Arabidopsis
thaliana. PLoS Biology, 8.
[2] Uyttewaal, M., Burian, A., Alim, K., Landrein, B., Borowska-Wykręt, D., Dedieu, A.,
Peaucelle, A., Ludynia, M., Traas, J., Boudaoud, A., Kwiatkowska, D. & Hamant, O. (2012).
Mechanical Stress Acts via Katanin to Amp
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 75
SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Bertrand Benazeraf
Mathias Beaupeux4, Martin Tchernookov4, Allison Wallingford2,
Tasha Salisbury2, Amelia Shirtz2, Andrew Shirtz7, Dave Huss2, 6,
Olivier Pourquié1,8,*, Paul François4,*, Rusty 6, Lansford 2, 5,*
Selected
Oral
nication
Commu
1 Institute of Genetics and Molecular and Cellular Biology (IGBMC), CNRS (UMR 7104), Inserm U964, Strasbourg University, France.
2 Department of Radiology and Developmental Neuroscience Program, Saban Research Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA.
3 Center for Developmental Biology (CBD), Center for Integrative Biology (CBI),
Toulouse University, CNRS, UPS, France.
4 Ernest Rutherford Physics Building, McGill University, Montréal, QC, Canada.
5 Keck School of Medicine, University of Southern California, Los Angeles, USA.
6 Department of Biological Sciences, University of Southern California, Los Angeles, USA.
7 Northern Michigan University Computer Science
and Mathematics Department, Marquette, USA.
8 Department of Genetics, Harvard Medical School and Department of Pathology,
Brigham and Woman’s Hospital, Boston, USA
Multiscale quantification of tissue behavior
during amniote embryo axis elongation
E
mbryonic axis extension is a complex multi-tissue morphogenetic process responsible for the
formation of the posterior part of the amniote body. Cells located in the caudal part of the
embryo divide and rearrange to participate in the elongation of the different embryonic tissues
(e.g. neural tube, axial and paraxial mesoderm, lateral plate, ectoderm, endoderm). We previously
identified the paraxial mesoderm as a crucial player of axis elongation, but how movements and
growth are coordinated between the different posterior tissues to drive morphogenesis remain largely
unknown. We use the quail embryo as a model system to quantify cell behavior and movements in
the various tissues of the elongating embryo. We first quantify the tissue-specific contribution to
axis elongation by using 3D volumetric techniques, then quantify tissuespecific parameters such
as cell density and proliferation at different embryonic stages. To be able to study cell behavior at
a multi-tissue scale we used high-resolution 4D imaging of transgenic quail embryos expressing
constitutively expressed fluorescent proteins. We developed specific tracking and image analysis
techniques to analyze cell motion and compute tissue deformations in 4D. This analysis reveals
extensive sliding between tissues during axis extension. Further quantification of “tissue tectonics”
showed patterns of rotations, contractions and expansions, which are coherent with the multi-tissue
behavior observed previously. Our results confirm the central role of the PSM in axis extension; we
propose that the PSM specific cell proliferation and migration programs control the coordination of
elongation between tissues during axis extension.
76 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
SESSION 3: MORPHOGENESIS & ORGANOGENESIS
Olivier Pourquié
Alexis Hubaud1,, Ido Regev2, L.Mahadevan2,3
and Olivier Pourquié1,2
1 Department of Genetics, Harvard Medical School and Department of Pathology, Brigham and Woman’s Hospital, USA
2 Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, USA
3 Departments of Organismic and Evolutionary Biology, and of
Physics, Wyss Institute for Biologically Inspired Engineering and Kavli Institute for Nanobio Science and Technology, Harvard University, Cambridge, USA
Keynote Speaker
Excitable dynamics of the segmentation clock
T
he periodic segmentation of the vertebrate body axis into somites, and later vertebrae,
relies on a genetic oscillator (the segmentation clock) driving the rhythmic activity of
signaling pathways in the presomitic mesoderm (PSM). While the clock is often presented
as a population of phase-entrained oscillators, whether its oscillations are an intrinsic property of
individual cells or represent a population-level phenomenon is not known. We show that oscillations
are a collective property of PSM cells which can be actively triggered in vitro by a dynamical quorum
sensing signal. We demonstrate that manipulation of mechanical cues is sufficient to predictably
switch isolated PSM cells from a quiescent to an oscillatory state in vitro, a behavior reminiscent of
excitability in other systems. Together, our work argues that the segmentation clock behaves as an
excitable system, introducing a novel paradigm to study such dynamics in vertebrate morphogenesis
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 77
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POSTERS
SESSION 1
(Even numbers)
- Thursday 27th of April 12:45 - 03:30pm
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80 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Hervé
ACLOQUE
P02
Cécilia
BASSALERT
P04
Raphaël
BONCHE
P06
Soline
CHANET
P08
Nathalie
COUTURIER
P10
Jean-François
DARRIGRAND
P12
Audrey
DESGRANGE
P14
Jocelyn
ETIENNE
P16
Julien
FALK
P18
Cécile
GASTON
P20
Muriel
GRAMMONT
P22
Marine
GUEYDAN
P24
Fisun
HAMARATOGLU
P26
Audrey
HARRIS
P28
Valeria
HERNANDEZ
P30
Alexandre
JANIN
P32
Thomas
JUNGAS
P34
Hanane
KHOURY
P36
Stéphanie
KILENS
P38
Nadieh
KUIJPERS
P40
Laurie-Anne
LAMIRÉ
P42
Jean-Antoine
LEPESANT
P44
Paul
MARCOUX
P46
Tamas
MATUSEK
P48
Christel
MOOG-LUTZ
P50
Pauline
NAUROY
P52
Amanda
OCHOA-ESPINOSA
P54
Anca
RADU
P56
Mélanie
ROUSSAT
P58
Maleaume
SOULARD
P60
Chantal
THIBERT
P62
Mathilde
TOCH
P64
Patrick
TORBEY
P66
Yusuke
TOYAMA
P68
Daan
VAN DEN BRINK
P70
Lucie
VAUFREY
P72
Alexis
WEINREB
P74
Zhiwen
ZHU
P76
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 81
Hervé Acloque
POSTER P02
Cecile Davaine, Eva Hadadi, Annelise Bennaceur-Griscelli and Hervé Acloque
Inserm, UMRS935 ESTeam Malignant and Therapeutic Stem Cell Models, Villejuif,
France & GenPhySE, Toulouse University, INRA, INPT, ENVT, Castanet Tolosan, France
Repetitive cycles of EMT/MET modulate mammary epithelial
cell behaviour and stemness
E
pithelial to mesenchymal transition (EMT) and its reciprocal, mesenchymal to epithelial
transition (MET) are important biological process required during embryonic development
for morphogenesis and organogenesis. By regulating cell adhesion and polarity, EMT allows
cell delamination and migration from one ancestral layer to form a new one and also to remodel
existing tissues. These process are governed by transcription factors (EMT-TFs) that are sequentially
expressed in different embryonic territories. More recently it has been proposed that cancer cells can
hijack this program to escape from primary tumors. Linked with the discovery that EMT-TFs can
also modulate the stemness of cancer cell, the molecular program governing EMT appears as a
central hub that controls cancer cell dissemination and metastasis formation. However an important
parameter controlling this process is time and as a full and massive EMT is observed in few hours at
gastrulation in amniotes, weeks, months or years can passed before EMT to be observed in tumors
and before metastasis development. Many parameters can concurs to this observation but our
hypothesis is that cancer cells are continuously exposed to antagonizing cues favoring either EMT
or MET. The repetition of EMT/MET cycles can finally change the ability of cells to suffer EMT and
lead them to escape from the primary tumor. To test this hypothesis, we exposed human mammary
epithelial cells (MCF10A) to four successive cycles of EMT/MET and analysed their molecular
and cellular properties during this process. Cycles were induced through addition and removal of
cytokines or through DOX-dependent induction of EMT-TFs. We observed that cells start to respond
better to EMT induction after some cycles and that they finally increase the expression of cancer
stem cell markers. Altogether our results support that repetition of EMT/MET cycles modulate the
ability of mammary epithelial cell to respond to EMT induction.
82 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Cécilia Bassalert
POSTER P04
Cécilia Bassalert, Adel Abo Regela, Nicolas Allègre, Claire Chazaud
UCA, INSERM 1103, CNRS 6293, France
Study of the influence of Igf on preimplantation mouse embryos
D
uring early mouse embryogenesis, there are two differentiation events leading to the lineage
specification of epiblast (Epi) and primitive endoderm (PrE), whose specific markers are the
transcription factors Nanog and Gata6 respectively.
It has been shown that supplementation with Igf during embryo culture promotes growth of
the embryos and a better evolution towards cavitation and blastocyst formation. This leads to
increased success of IVF with these embryos, in several mammals species.
Here the influence of the Igf pathway on lineage specification/differentiation is studied by
carrying out embryo cultures with different treatments (Igf supplementation and different
inhibitors of the Igf pathway) during precise developmental windows. Specific lineage
markers were analysed by confocal microscopy and quantified through ImageJ/Imaris.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 83
Raphaël Bonche
POSTER P06
Bonche Raphaël, Chessel Aline, Pizette Sandrine, Therond Pascal
Valrose Biology Institute, UMR CNRS 7277, Inserm U1091, UNS, UCA, France
Perlecan, a basement membrane component, is transcriptionally
regulated by Decapentaplegic, a TGFβ Drosophila homolog
T
he Basement membrane (BM) is a specialized extracellular matrix that surrounds organs and
acts both as a solid support and as a signaling platform for these organs. During development,
organs undergo morphogenesis: they grow, are patterned and change their 3D-organization.
Throughout this process, control by morphogens, the BM has to adapt to the volume and shape
modification of tissues to which it is associated. This implies a modulation of the amount of deposited
BM and probably of its composition. This modulation could be directly controlled by morphogens, but
whether a link between these signaling molecules and the transcriptional/translational regulation of
BM components exist remains totally elusive. Perlecan (Pcan), the main heparan sulfate proteoglycan
of the BM, has multiple putative isoforms in all species. In Drosophila melanogaster, some of these
isoforms result from the presence of an alternative transcription start site (Flybase: http://flybase.
org/). Consequently, by using D.melanogaster as an in vivo model system, our aim is to characterize
pcan transcriptional isoforms, and then to determine whether morphogens influence BM dynamics
and tissue integrity through the differential regulation of pcan transcriptional isoforms. To do so,
we have designed isoform-specific RNA in situ hybridization probes and are currently generating
isoform-specific antibodies. Our preliminary results in the wing imaginal disc, which will be presented
here, indicate that this tissue produces only one of the transcriptional isoforms due to regulation of
both transcription start sites by Decapentaplegic (Dpp) morphogen. This work could have important
consequences on the aetiology of human syndromes implicating BM components.
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Soline Chanet
POSTER P08
Soline Chanet, Adam Martin
MIT, Department of Biology, Cambridge, UK
Myosin activity and mitotic rounding orients cell divisions
in columnar epithelia
D
uring epithelial cell proliferation, planar alignment of the mitotic spindle allows the two
daughter cells to stay within the epithelium and participate in epithelial architecture and
integrity. Previous works have identified different cortical cues that regulate spindle orientation
by recruiting the dynein/dynactin motor complex, which exert pulling forces on astral microtubules.
The dynein/dynactin complex interacts with the conserved Mud/NuMA complex, which is typically
recruited to the cortex by Pins/LGN. However, depending on the tissue and of the type of division,
the cortical cues that regulate spindle orientation vary. In addition, other examples have shown
that anisotropies in cell shape can serve as a division polarizing cue even without specified polarity
domains around the cortex. Here, we investigate the interplay between cortical cues and cell shape
in a proliferating tissue. We analyze division orientation in the first mitotic divisions of the early
Drosophila embryo, where groups of epithelial cells synchronously divide. Using chemical inhibition,
knock-down, and mutants that reduce motor activity, we show that myosin 2 activity is required
to orient cell divisions in the plane of the epithelium. Loss of myosin 2 activity causes the spindle
to preferentially orient perpendicular to the epithelial plane. Our results suggest that the effect of
myosin 2 on spindle orientation is independent of Pins cortical localization. Indeed, Pins planar
localization is not affected when myosin is disrupted. However, we show that myosin 2 motor activity
and its cortical recruitment is required for cell rounding upon mitotic entry in columnar epithelia. Our
findings suggest that mitotic rounding in columnar epithelia allows cells to read the cortical cues
that orient the spindle. In absence of mitotic rounding, geometrical cues imposed by columnar tissue
packing prevails.
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Nathalie Couturier
POSTER P10
Nathalie Couturier1, Alexandre Guiraud1, Claire Burny2, Stéphane Janczarski2,
Yohann Couté3, Alexandra Kraut3 and Vincent Gache1
1 U1217, UMR 5310, INMG, MNCA team, INSERM, CNRS,
Claude Bernard University Lyon 1 , France
2 UMR 5239, LBMC ¬ENS Lyon - CNRS , France
3 U1038 INSERM/CEA/UGA, Large scale biology laboratory, Grenoble, France
Microtubules proteome and nuclei positioning
during skeletal muscle development
S
keletal muscle fibers are built from fusion of specialized cells (myoblasts) that produces
a syncytium (myotubes). Those myotubes contain hundreds of nuclei that undergo many
movements, simultaneously with myotubes maturation process, until reaching a final
localization at the periphery of mature fibers (myofibers). Disorganization of nuclei disposal is always
associated with myofibers misfunctioning (i.e.: sarcopenia, centronuclear myopathy). Consequently,
peripheral nuclei positioning in mature fiber appears to be essential for muscle fibers functionality.
Previous study demonstrated that nuclei positioning is a reversible process suggesting that in
pathologies presenting nuclei mislocalization, re-localizing nuclei can contribute to the restoration
of certain muscular functionalities. Actin and microtubule networks have been shown to contribute
to nuclei localization (alignment/peripherization) in myotubes/myofibers. As microtubule network is
completely redesigned during muscle formation and maturation, all microtubule-associated-proteins
(Maps) can potentially be involved in the precise localization/maintenance of myofibers nuclei
patterning. We hypothesize that the difference between proteome associated with microtubules
in immature (myotubes) and mature (myofibers) fibers contribute to microtubule reorganization
and nuclei localization. Consequently, revealing microtubules associated proteome in muscle cells
in early and late stages of differentiation will allow the identification of potential new regulators of
myonuclei positioning and consequently muscle functionality. We developed a mass-spectrometry
strategy to analyze those two proteomes using an original system that allows the formation of
“mature” muscle fibers in vitro. This strategy conduct to the selection of 244 candidates that we are
currently investigating using a siRNA screen-approach using both immortalized muscle C2C12 cells
and primary murine muscle cells. An unbiased assay was developed by our team using in ImageJ®
software combined with a statistical analysis in RStudio® software to automatically extract myofibers
parameters such as fusion capacity, myofiber thickness, nuclear positioning/distribution and triads
formation. This approach will lead to the identification of new pathways
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Jean-François Darrigrand
POSTER P12
Jean-François Darrigrand, Bruno Cadot, Vanessa Ribes
Institute of Myology, Jacques Monod Institute, France
Impact of a perinuclear phosphatase on heart morphogenesis
D
ullard is a perinuclar associated phosphatase, which has been shown necessary for proper
embryonic development. This protein was first characterized in 2002 in Xenopus, where
knocking down Dullard results in failure of neural tube development and severe head
reduction. In the mice, Dullard full knock-out leads to embryonic death at mid-gestation. Recently,
some published papers notably showed that dullard is ubiquitously expressed and necessary for the
proper development of various tissues, as primordial germ cells, skeleton and nephron.
T
o investigate the role of Dullard during embryonic development we conditionally delete Dullard
from neural crest cells in developing mice. Cardiac neural crest cells are delaminating from
the neural folds between the mid-otic placode and the posterior part of the third somite. They
are known to regulate outflow tract septation and elongation. We present here the results of crossing
Pax3Cre and Wnt1Cre driver lines with the DullardFlox line. We observe that mutant embryos are
mostly dying after 12.5 days of development, never reaching birth and presumably dying because of a
heart defect. The embryos knocked-out for dullard in the neural crest cells present a heart phenotype
with strong defects in outflow tract septation. The aortic and pulmonary tracts fail to divide properly,
and exhibit impaired orientation and size. Our results point to an involvement of the BMP signalling
pathway, and Dullard could modulate this pathway by acting on Smad 1/5/8.
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Audrey Desgrange
POSTER P14
Audrey Desgrange (1), Johanna Vanderhaeghe (1), Jean-François Le Garrec (1),
Lucile Houyel (2) and Sigolène Meilhac (1)
(1)Imagine - Pasteur Institute, Laboratory of Heart Morphogenesis, Paris, France ; (2)
Department of Pediatric Cardiac= Surgery, Chirurgical Center Marie Lannelongue,
Le Plessis Robinson, France
Dissecting the role of the left determinant Nodal for heart looping
I
n bilateral organisms, left-right patterning of the embryo is essential for the asymmetric
morphogenesis of visceral organs such as the heart. Establishment of left-right patterning has
been well characterized, with signaling, initiated in the node, of the TGFβ secreted factor Nodal as
a major left determinant. However, how this molecular asymmetry is transposed into asymmetric
morphogenesis has remained poorly understood. Heart looping is the first morphological sign of
left-right asymmetry during embryonic development. It corresponds to a rapid change in the heart
geometry, from a straight tube to a helical tube. This process, which is required for cardiac chamber
alignment impacts the circulation of the blood. In humans, mutations in components of the Nodal
pathway are associated with heterotaxy, including defects in the lung, spleen and also complex
cardiac malformations. In the mouse model, mutant hearts with impaired left-right signaling have
been described for the direction of heart looping but not for the heart tube geometry. We have recently
proposed a computer model of heart looping and developed tools to quantify heart geometry in
3D based on High Resolution Episcopic Microscopy imaging and image segmentation. Here we
investigate where Nodal signaling is received by cardiac progenitors and how this contributes to
embryonic heart looping and the mature heart structure.
U
sing a transgenic line, we have traced cells that have expressed Nodal and quantified their
contribution to the heart tube during looping. We have also generated conditional Nodal
mutants in different populations of cardiac progenitors and found specific looping defects.
Our analyses of conditional Nodal mutants at birth show that such defects in heart looping lead to
malformations of the mature heart.
O
ur work is expected to provide novel insight into the role of left-right patterning during heart
formation and its relevance to congenital heart defects with chamber misalignment.
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Jocelyn Etienne
POSTER P16
Mahamar Dicko, Pierre Saramito, Guy B. Blanchard, Claire M. Lye,
Bénédicte Sanson, Jocelyn Étienne
MD, PS, JE : CNRS - Grenoble Alpes University, France
GBB, CML, BS : Univ. Cambridge, UK
Geometry Can Provide Long-Range Mechanical Guidance for
Embryogenesis Geometry Can Provide Long-Range Mechanical
Guidance for Embryogenesis
M
orphogenesis is a three-dimensional process during which an organism undergoes
complex deformations to acquire a given shape and organisation. The genetic patterning
of Drosophila embryos and the way it regulates key molecules and complexes, such
as actomyosin, is well described. How the motor Myosin II generates local mechanical action is
understood, however, the way this integrates at the scale of the embryo to drive morphogenetic
movements is still to be characterised. Axis extension in Drosophila is a good model system for this,
since it involves the deformation of the whole of the embryonic epithelium. It is dependent on a wellcharacterised anisotropic myosin recruitement pattern in the germband tissue, where actomyosin
organises in oriented supracellular cables through a planar-polarisation mechanism.
O
ur prediction of local mechanical behaviour is based on a rheological law recently validated
for cortical actomyosin [1,2] and extend to the case when myosin generates an anisotropic
prestress [3]. In order to resolve the stresses and deformations produced at the scale of
the whole embryo, we develop a novel finite element technique which allows us to solve the threedimensional mechanical balance resulting from a given global distribution of myosin-generated
prestress.
N
umerical simulations confirm that the planar-polarised arrangement of myosin in the
germband can trigger embryo-scale flows similar to those observed experimentally.
Interestingly, this mechanical behaviour is shown not to rely necessarily on cell intercalation,
but rather on the anisotropy of myosin action, which can entail cell elongation as well as intercalation.
We also show that the mechanical balance that leads to axis extension towards the posterior of the
embryo is crucially dependent on the embryo’s geometry, including the presence anteriorly of the
cephalic furrow, which can act as a guide for morphogenetic movements.
[1] Étienne et al., PNAS 112:2740, 2015.
[2] Machado et al., BMC Biol. 13:98, 2015.
[3] Dicko et al., bioRxiv 075309, 2017.
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Julien Falk
POSTER P18
Julien Falk, Leila Boubakar, Karine Thoinet, Hugo Ducuing, Florie Reynaud,
Edmund Derrington, Valérie Castellani
NeuroMyoGene Institute UMR CNRS 5310 INSERM U 1217,
University of Lyon1 Claude Bernard Lyon1, Lyon, France
Molecular memory of morphologies by Septins during neuron
generation allows early polarity inheritance
T
ransmission of polarity established early during cell lineage history is emerging as a key
process guiding cell differentiation. Highly polarized neurons provide a fascinating model
to study inheritance of polarity over cell generations and across morphological transitions.
Neural crest cells (NCCs) migrate to the dorsal root ganglia to generate neurons directly, or after cell
divisions in situ. Using live imaging of vertebrate embryo slices we found that bipolar NCC progenitors
lose their polarity, retracting their processes to round for division, but generate neurons with bipolar
morphology by emitting processes from the same locations as the progenitor. Monitoring the
dynamics of Septins, which play key roles in yeast polarity, indicates that Septin-7 tags process sites
for re-initiation of process growth following mitosis. Interfering with Septins blocks this mechanism.
Thus, Septins store polarity features during mitotic rounding so that daughters can reconstitute the
initial progenitor polarity.
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Cécile GASTON
POSTER P20
Cécile Gaston
Jacques Monod Institute, CNRS UMR7592, France
Role of EpCAM in epithelial migration
R
ecent work in our lab showed that EpCAM, a transmembrane protein specifically expressed in
epithelia, is involved in the enterocyte organization and polarization through actin cytoskeleton
arrangement. Notably, polarized EpCAM-silenced cells show an unusual modification of
tensile force homeostasis and actomyosin relocation at multicellular contacts.
My project aims at understanding how EpCAM participates in the cell response to mechanicals
properties of the cellular microenvironnement to maintain the epithelial monolayer integrity.
Preliminary results show a perturbation of actin stress fibers along with changes in focal adhesion
morphology and distribution. In a first part, I investigate whether these modifications impact epithelial
cell spreading and migration. In addition, I dissect the molecular mechanism(s) of action of EpCAM in
epithelial cells, to understand how EpCAM could modulate myosin-II activity and/or the recruitment
of actin regulators at the cell-substrate interface. The second part of my project will position EpCAM
participation in epithelial morphogenesis in a more physiological context, by using microfabrication
techniques and an enterocyte 3D culture system that mimics intestinal villus topography. These 3D
culture substrates will be routinely used to assess collective epithelial cell dynamics in presence and
absence of EpCAM.
The outcomes of my PhD project will participate to improve the knowledge on the participation of
the actin network to the epithelial integrity, as well as the fundamental understanding of physical
constraints on epithelial cell organization and dynamics.
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Muriel Grammont
POSTER P22
Muriel Grammont, Pascale Milani, Jean-Luc Duteyrat, Laurie-Anne Lamiré,
Julien Chlasta, Letitia Arias, Arezki Boudaoud
1 Lyon Univ, ENS de Lyon, CNRS UMR 5239, INSERM U1210, Biology and cell modelisation laboratory, Lyon, France.
2 NeuroMyoGene Institute, Claude Bernard University Lyon 1, CNRS UMR 5310,
INSERM , Villeurbanne, France.
3 Reproduction and developpment of plants laboratory, Univ Lyon, ENS de Lyon, UCB Lyon
1, CNRS, INRA, Lyon, France.
The mechanics and genetics of epithelial cell flattening
T
he model we are using to study epithelial morphogenesis is the follicular epithelium in
Drosophila melanogaster. It consists of a monolayer of 800 epithelial cells that contact
apically an internal cluster of 15 nurse cells and the oocyte and basally an external basement
membrane. During follicle development, the epithelial cells undergo a cuboidal-to-squamous
transition around the nurse cells and a cuboidal-to-columnar transition around the oocyte. We and
others have previously shown that cell flattening depends on Cadherin-based adherens junction
remodelling and on the growth of the germline. Our aim is to define the genetic and mechanical
processes driving cell flattening by looking at the contribution of the germline, of the basement
membrane and of the epithelial cells. To analyse the role of the germline growth, we are measuring
the osmotic pressure within the germline in WT and in mutants with altered growth by using an
atomic force microscope (AFM), and analyse the impacts of these mutants on the flattening of the
squamous cells. Our results show that an antero-posterior gradient of pressure, with more pressure
in anterior nurse cells, exists within the cyst and that this difference is involved in patterning cell
flattening. To analyse the role of the BM, we also use the AFM to determine its mechanical properties.
Our data first show that BM stiffness increases during follicle development and that its structure,
made of fibrils, anisotropically stiffen the BM. This validates the current model for the BM to behave
as a corset around the follicle to force it to elongate around the A/P axis. Second, we show that
the BM presents an antero-posterior gradient of stiffness, inverse to that observed in the germline
cells, and that softening of BM depends on TGFß pathway and BM interactions are required for cell
flattening. Altogether, these results demonstrate the importance of mechanical properties of tissues
interacting with epithelial cells for their morphogenesis.
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Marine Gueydan
POSTER P24
Marine Gueydan, Bérangère Pinan-Lucarré, Aurore-Cécile Valfort, Jean-Louis Bessereau
INMG-CNRS UMR5310-INSERM U1217- Claude Bernard University Lyon, France
Identification of novel regulators of GABAergic synaptogenesis
in the nematode Caenorhabditis elegans
I
n the central nervous system (CNS), the inhibitory system plays a key role in neuronal network
excitability. To identify novel genes and mechanisms involved in the formation and regulation of
inhibitory synapses, we use the inhibitory GABAergic neuromuscular junction of the nematode C.
elegans as a genetically tractable model. At these synapses, fast neurotransmission is ensured by
type A ionotropic GABA receptors (GABAAR), which form post-synaptic clusters in front of GABAergic
buttons.
We performed an unbiased EMS genetic screen based on the visualization of fluorescently tagged
GABAAR in vivo in a knock-in strain. We identified 56 mutants with abnormal GABAAR localization.
For 36 mutants, we used a novel WGS strategy to simultaneously map and identify causative
mutation without any prior time-consuming genetic mapping. We found 7 alleles of genes already
known to be involved in synaptogenesis, such as genes encoding master regulators of neuronal
identity (the transcription factors UNC-30, a Pitx family member, and UNC-3, a COE motif family
member), presynaptic organizers (SYD-2/liprin), postsynaptic scaffold proteins (FRM-3, an ERM
domain protein, and LIN-2/CASK) and the netrin receptor UNC-40/DCC. For 9 mutant strains, we are
currently completing the validation of candidate genes, which are known to be involved in various
cellular processes, such as transcription factors, motor proteins or extracellular matrix components.
We started the functional characterization of a novel candidate gene, tentatively named nsp3, which encodes an evolutionarily conserved transmembrane protein. nsp-3 mutation causes a
severe reduction of synaptic GABAAR and the presence of small ectopic punctae in muscle cells. We
reproduced this phenotype by generating a complete nsp-3 deletion using CRISPR technology. We
are now investigating its expression pattern, subcellular localization and role in GABAAR trafficking
and localization. Though a few publications showed that other members of this family were involved
in cellular adhesion, phagocytosis and immune response in Drosophila, nothing is known about
their function in the CNS. Our data should identify novel functions of these proteins in the traffic or
synaptic localization of neurotransmitter receptors in the nervous system.
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Fisun Hamaratoglu
POSTER P26
Justine Pascual, Jelle Jacobs b, c, *, Leticia Sansores b, Malini Natarajan d, Julia Zeitlinger
d, e, Stein Aerts c, Georg Halder b, Fisun Hamaratoglu a
a Center for Integrative Genomics, University of Lausanne, Lausanne 1015, Switzerland
b VIB Center for the Biology of Disease and KU Leuven Center for Human Genetics,
University of Leuven, Leuven 3000, Belgium
c Laboratory of Computational Biology, Center for Human Genetics, University of Leuven, Leuven 3000, Belgium d Stowers Institute for Medical Research, Kansas City, MO, 64110, USA e Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, USA
The Hippo pathway acts as a gatekeeper to restrict
EGFR/Ras/Raf driven tumorigenesis
T
ransformation of a healthy cell into a cancerous one requires multiple mutations. Intriguingly,
oncogenes and tumor suppressors are often members of developmental signaling pathways
that shape our bodies. A striking example of this is the EGFR pathway, activity of which is
absolutely essential for cell fate specification and yet its activation drives almost all carcinomas.
What determines the outcome of EGFR activation (differentiation vs proliferation), however, remains
unknown. Here we show that the level of Hippo pathway activity determines the cellular response
to EGFR stimuli. We use the imaginal discs of Drosophila as models of epithelial carcinogenesis to
study the interaction between the EGFR and Hippo pathways. We find that the activation of EGFR
pathway in cells where the Hippo activity is compromised leads to a dramatic hyper-proliferation of
these cells and the resulting organ is up to 10 folds larger than normal. Using RNA-sequencing and
ChIP-Nexus analysis, we reveal that this impressive synergistic overgrowth is due to an intimate
connection between the two pathways: Hippo reprograms the response to EGFR activation by directly
controlling the levels of its transcription factors, Capicua, Yan and Pointed. Mutations in the Hippo
pathway components thus greatly contribute to the transformation of cells with activating mutations
in the EGFR pathway during carcinogenesis.
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Audrey Harris
POSTER P28
Audrey Harris, Amandine Collin, Gauhar Masgutova, Maria Hidalgo-Figueroa,
Cédric Francius, Benvenuto Jacob, Frédéric Clotman
Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural
Differentiation, Brussels, Belgium. Université catholique de Louvain,
Institute of Neuroscience, System and Cognition division, Brussels, Belgium.
Identification of regulators of ventral interneuron diversification
and migration during spinal cord development
L
ocomotion is a complex behavior coordinated by Central Pattern Generators
located in the ventral regions of the spinal cord. These circuits are composed of motor neurons
and of populations of interneurons. Ventral interneurons derive from 4 distinct cardinal
populations, V0, V1, V2 and V3, which diversify into multiple subsets. Each subset of interneurons
migrates to a defined position within the spinal cord to adequately integrate in locomotor circuits.
However, the molecular and cellular mechanisms that control the diversification and the migration
of spinal interneurons remain elusive. Data obtained in our laboratory showed that the Onecut
transcription factors are expressed in several subsets of ventral interneurons in the developing spinal
cord. Here, using compound mutant mice for Hnf6 and Oc2, we report that Onecut factors control the
diversification and the migration of ventral interneurons during embryonic development.
We observed that Onecut proteins are required for the production of a V2a subpopulation characterized
by the cMaf expression, and of V2c interneurons. In the absence of Onecut factors, quantitative
analyses of the distribution of ventral populations unveiled alterations in the migration of V2a, V2b
and V3 interneurons. To identify regulators of these processes, we compared the transcriptome
of control and of Onecut compound mutant embryonic spinal cord by microarray analyses. This
approach enabled to identify Pou2f2 downstream of Onecut factors. We identified neuronal isoforms
of Pou2f2, and showed that Pou2f2 is overexpress in the spinal cord in the absence of Onecut factors.
We are currently determining, by loss or gain of function experiments, how Pou2f2 is implicated in
spinal cord development. Our results show that Onecut factors control the diversification and the
migration of certain ventral interneuron populations during spinal cord development. Experiments
are ongoing to assess whether Pou2f2 downstream of Onecut factors is involved in any of these
processes.
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Valeria Hernandez
POSTER P30
Valeria Hernandez, Stève de Bossoreille, Mariana Benitez and Arezki Boudaoud
Ecole Normale Superieur de Lyon France
Universidad Nacional Autonoma de Mexico, Mexico
Feedback interactions between turgor pressure
and plasmodesmata permeability
C
ompared to animals, plant cells are encased within the cell wall and so their development
lacks of cell migration. Instead, plant development relies on controlled cell elongation and
growth. Important to both of these processes is the build-up of turgor pressure which can
be directly regulated by the movement of water by water transporters, called aquaporins, and by
plasmodesmata (PD), which are intercellular channels. PD are also permeable to hormones,
mobile proteins, metabolites and, therefore, they can also help to change the osmotic pressure and
to establish spatial patterns of signalling molecules. The permeability of PD can be spatially and
temporarily regulated during plant development by the deposition and degradation of callose – a
β-glucan – at PD necks. But, what cues do they respond to? This question is still under investigation.
There is some evidence that suggests that differential pressure forces, and particularly turgor,
between neighbouring cells are able to modify the permeability of PD. The experimental evidence
also suggests that the interactions between PD permeability and turgor goes in the other way around
as PD channels are more closed during cell elongation of cotton cell fiber which, presumably, helps
to build-up turgor pressure. Our work aims at studying some pending questions regarding the
feedback interactions between turgor and PD permeability using a combination of computational
and experimental approaches.
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Alexandre Janin
POSTER P32
Alexandre Janin, Delphine Bauer, Camille Valla, Emilie Chopin,
Nathalie Streichenberger and Alexandre Méjat
Hospices Civils de Lyon, NeuroMyoGene Institute (INMG) – CNRS UMR 5310/INSERM
U1217/UCBL1, Claude Bernard University Lyon, France
BMP4 pathway alterations in LMNA-/- myoblasts
induce premature muscle differentiation
T
he LMNA gene encodes two important proteins of the nuclear lamina, a major network of
intermediate filaments covering the inner nuclear membrane, lamin A and lamin C. Mutations
in this gene are responsible for different diseases grouped under the term “laminopathies”.
The most famous laminopathy is the accelerated aging syndrome called “Hutchinson-Gilford
Progeria syndrome”. LMNA mutations could also lead to abnormalities in adipose tissue (Dunnigantype familial partial lipodystrophy, FPLD) or in peripheral nerve (Charcot-Mari-Tooth type 2).
Nevertheless, most of LMNA mutations have been associated with Emery-Dreifuss muscular
dystrophy (EDMD-2) which is clinically characterized by dilated cardiomyopathy, muscle weakness
and muscle atrophy associated with early contractures.
In order to better study the alteration of muscle stem cells in EDMD-2, also called satellite
cells, a model of murine conditionally immortalized myoblasts inactivated for Lmna gene has
been generated. These cells, called H-2K, express a thermosensitive form of SV-40 large T
antigen under the control of an IFNγ-responsive promotor. They can be maintained in proliferation at
33°C in presence of IFNγ or switched to differentiation at 37°C in absence of IFNγ.
These cell lines were used to compare gene expression profiles in Lmna-/- H-2K cells with wildtype
H-2K myoblasts. Several alterations of the Bmp4 pathway were identified. BMP4 signaling is a
crucial pathway for the control of the switch from proliferation to differentiation of satellite cells after
a muscle damage. This pathway had also been described as essential to regulate muscle mass.
This study shows that the alterations of BMP4 pathway lead to the precocious differentiation of
Lmna-/- myoblasts which could explain the depletion of muscular stem cells pool observed in EDMD
patient. Moreover, modulation of this pathway seems to be a good key to reverse the precocious
differentiation phenotype.
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Thomas Jungas
POSTER P34
Jungas Thomas, Tasca Alexia, Davy Alice
CNRS UMR5547, Toulouse, France
Aneuploidy in mammalian brain and its implication in neuronal diversity
T
P
he vast diversity of neurons that reside in adult mammalian brains arise from a unique
population of neural progenitor cells (NPCs). Their peculiar mode of division during embryonic
neurogenesis balances between self-renewal and differentiation.
revious studies suggest that 1/3 of these NPCs in the mouse neocortex could be aneuploid meaning hyperploids or hypoploids. A significant proportion of these aneuploid NPCs appear
to escape from programmed cell death and not only persist as neurons or glia during postnatal
development but can be integrated in active neural circuitry. The same trend has been reported in the
human CNS and variation of aneuploid neuronal cell population is observed in pathological context
(Down syndrome, Alzheimer’s disease, schizophrenia or autism).
T
he identification of aneuploid neurons in the mammalian brain raise exciting questions about
their functions and the mechanisms for their generation. Why aneuploid neurons exist among
their euploid sibling? When and how are they generated? Is this aneuploidy restricted to a
specific type of neurons? Could they be an additional source of neuronal diversity?
To answer some of these questions, we focus on polyploid neurons. Indeed, we and other recently
showed that polyploid neurons are present perinatally in the mouse neocortex and that neuronal
polyploidy is genetically encoded since pups mutant for Eph-ephrin signaling showed a depletion in
cortical polyploid neurons.
U
sing FACS analysis, we precisely quantified the proportion of polyploid neurons in wild type
mouse brain at different developmental stages. In addition, we are performing immunostaining
to better characterize these polyploid neurons. Further, using in vitro NPCs culture and live
imaging, we are studying the cellular and molecular mechanisms that lead to neuronal polyploidy.
Altogether, our study will lead to a better understanding of neuronal polyploidy in the mammalian
brain.
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Hanane Khoury
POSTER P36
Khoury Hanane, Jaffredo Thierry
UPMC, Sorbonne univerisity, CNRS, INSERM, France
Molecular control of the endothelial to hematopoietic
transition during aortic hematopoiesis
I
n Vertebrates, the first hematopoietic stem cells (HSCs) emerge at the level of the aortia during
the earliest phases of embryogenesis. These cells are formed from pre existing endothelial cells,
localised in the aortic floor, endowed with the capacity to produce blood cells hence designated as
hemogenic.
HSCs are used clinically to treat a wide array of diseases, including acute leukaemias and congenital
blood disorders, but obtaining suitable numbers of cells and finding immune-compatible donors
remain serious problems. These difficulties have led to an interest in the conversion of diverse sources
of cells into HSCs, a conversion not possible using current methodologies.This is part because the
earliest phases of HSC emergence from hemogenic endothelium and the control of this endothelialto-hematopoietic transition (EHT) remain poorly understood due to the low number of hemogenic
endothelial cells in the embryo and to the difficulties to capture the fleeting EHT.
We have recently designed a controlled in vitro system mimicking the commitment of mesodermal
cells into endothelial cells followed by commitment into hemogenic endothelial cells and into
hematopoietic cells. Starting from pieces of uncommitted mesoderm, namely the presomitic
mesoderm, isolated from the early avian embryo, we are able to massively (around 70%) convert
these cells. This conversion is achieved in the presence of a controlled cocktail of growth factors and
cytokines. This system is very reproducible, since the different cell populations appear at precise time
points, can be imaged and allows having access to discrete steps along this commitment pathway.
Taking advantage of this approach, we are establishing the molecular landscapes of the hemogenic
endothelium and of the EHT using global transcriptomal analysis NGS followed by identification of
key regulators. We will validate these key regulators of hemogenic endothelium commitment and of
EHT in vitro on cultures and in vivo on the chicken embryo.
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Stéphanie Kilens
POSTER P38
Stéphanie Kilens1, Diego Moreno1, Dimitri Meistermann1,4, Arnaud Reigner1,3, Caroline
Chariau2, Anne Gaignerie2, Yohann Lelièvre4, Céline Vallot5, Jenna Lammers1,3, Claire
Pecqueur6, Claire Rougeulle5, Paul Barrière1,3, Jérémie Bourdon4, Magali Soumillon7,
Tarjei S. Mikkelsen7, Thomas Fréour1,3 and Laurent David1,2.
1 INSERM Center for Research in Transplantation and Immunology (CRTI) UMR 1064, University of Nantes, France;
2 INSERM UMS 016, SFR Francois Bonamy, iPSC core facility, Nantes, France
3 Nantes University Hospital Center, Biology of reproduction service, Nantes, France
4 Université de Nantes, Ecole des Mines de Nantes, CNRS,
Computer laboratory Nantes Atlantique (LINA UMR 6241), Nantes, France
5 Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR 7216 CNRS,
Paris University Diderot, Paris, France;
6 CRCNA - INSERM UMR 892 - CNRS UMR 6299, Nantes University, France;
7 Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge,
MA 02138, USA; Broad Institute, Cambridge, USA; Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
Direct reprogramming of human somatic cells into human naive
induced pluripotent stem cells to study human pluripotency regulation
P
luripotent stem cells possess the unique ability to self-renew and differentiate into all foetal
cell types, making them invaluable tools to study human development and model diseases.
In mammals, pluripotency exists in two states: naive pluripotency that represents the ground
state of pluripotency found in the preimplantation epiblast, and primed pluripotency that corresponds
to cells poised for differentiation found in the post-implantation epiblast. Due to the preciosity of
human embryos, understanding the regulation of human pluripotency necessitates cellular models
closely mimicking human epiblast cells. To date, the majority of human embryonic stem cell (hESC)
lines are in primed state of pluripotency, and identifying culture conditions supporting human naive
pluripotency has been a major goal in the field. Recently, two laboratories succeeded in the derivation
of human naive pluripotent stem cell lines but they are from embryonic origin, raising ethical issues
and limiting the array of genetic backgrounds that can be studied. To circumvent those problems, I
designed a protocol to directly reprogram patient-specific somatic cells into human induced naive
pluripotent stem cells (hiNPSC). I generated 17 cell lines from 3 different somatic backgrounds.
We obtained an array of hiNPSC, depending of the medium used to maintain naive pluripotency,
with different levels of naive pluripotency achieved. Using human preimplantation epiblast cells as
a benchmark, we use the diversity of our cell lines to propose a ranking of markers to characterize
human naive pluripotency, among metabolic activity, transcriptomic profile, protein expression and
X-Chromosome status. Our protocol will improve accessibility of human naive pluripotent stem cells
to laboratories as there is no restriction to the use of hiNPSC. Moreover, this protocol enables the
generation of both naive and primed pluripotent cells from the same genetic background which are
essential tools to mimic pluripotency in the early embryo and thus study pluripotency regulation.
100 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Nadieh Kuijpers
POSTER P40
Nadieh Kuijpers, Reinhard Windoffer and Rudolf E. Leube
Institute of Molecular and Cellular Anatomy, Uniklinik RWTH Aachen, Germany
Keratin intermediate filament dynamics during epithelial cell migration
C
ytoskeleton dynamics are highly regulated and important for proper cell migration. The
most abundant cytoskeletal components in epithelial cells are the keratin intermediate
filaments. And yet, the involvement of keratin intermediate filaments in cell migration is
mostly unknown. Combining confocal imaging in primary human keratinocytes with cytoskeletal
targeted drug treatments and micro-patterning, we aim to dissect the interdependence of keratin
intermediate filaments and the other two major cytoskeleton components, actin filaments and
microtubuli, during cell migration. Using image analysis tools, keratin dynamics can be quantified
and compared between differently treated keratinocytes. Keratin dynamics can also be compared
to movement of the other cytoskeleton components. This has led to the observation that the actinmyosin system moves from the plasma membrane toward the cell interior together with newlyassembled keratin particles until it encounters the keratin network, whereupon its movement slows
down and separates from the keratin system. Thus, a clear border between the actin and keratin
cytoskeleton is delineated in the migrating kertinocytes distributing different biomechanical functions
to each system for the preservation of tensegrity while maintaining information exchange between
both within the border region. It is not clear yet whether keratin intermediate filaments interact with
microtubuli in a similar matter. Initial experiments indicate that this is not the case, since the keratin
and microtubule networks co-localise in large parts of the cytoplasm. The molecular nature of the
different interactions between the three major cytoskeletal components remains to be elucidated.
Preliminary observations suggest that they involve the motor proteins myosin IIa and dynein
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 101
Laurie-Anne Lamiré
POSTER P42
Muriel Grammont, Pascale Milani
ENS Lyon UMR CNRS 5239 INSERM U 1210, France
Mechanical role of the germline during epithelial cell morphogenesis
in Drosophila ovarian follicle
E
pithelial morphogenesis is essential to shape organs and tissues. We use Drosophila ovarian
follicle as a model to study cell flattening. A follicle is composed of 16 growing germline cells
(15 nurse cells and one oocyte) surrounded by a monolayer of 800 cuboidal epithelial cells. At a
specific stage of development, 50 of them flatten like a wave from anterior to the middle of the follicle.
The direction of this flattening is in part due to the presence of an osmotic gradient of pressure from
the underneath germline cells. Importantly, all the germline cells are connected through cytoplasmic
bridges that are used to transfer the cytoplasm to the posteriorly localized oocyte.
H
ere, we investigate the mechanisms leading to i/the generation of an osmotic gradient
pressure and ii/the pathways activated in the stretched cells in response to this mechanical
force. By using confocal microscopy and Atomic Force Microscopy (AFM), we showed that
the number of entrance cytoplasmic bridges influences the pressure. We also proposed that the
diameters of the cytoplasmic bridges are likely to be involved in the establishment of the gradient,
as those connecting the oocyte are wider than the others. In addition, by using 3- dimensionnal
reconstructions of follicles, we are currently testing the role of the differential growth of the nurse
cells by measuring the change in volume of the germline cells during cell flattening.
F
inally, the molecular mechanism leading to cell flattening and influenced by a mechanical
stimulus from the germline pressure is currently investigating by analysing the Hippo pathway
activity within the stretched cells. To conclude, we propose that the growth of the germline
cells influences mechanically and genetically the stretched cells that flatten in order to allow follicle
elongation.
102 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Jean-Antoine Lepesant
POSTER P44
N. Tissot1, J.A. Lepesant1, F. Bernard1, K. Legent1, F. Bosveld2, C. Martin2, O. Faklaris1,
Y. Bellaïche2, M. Coppey1, A. Guichet1
1. Jacques Monod Institute, CNRS UMR 7592, Paris-Diderot University, France
2. Curie Institute, CNRS UMR 3215 , INSERM U934, France
Distinct molecular cues ensure a robust microtubule-dependent
nuclear positioning in the Drosophila oocyte
C
ontrolling nucleus localization is crucial for a variety of cellular functions. In the Drosophila
oocyte, nuclear asymmetric positioning is essential for the reorganization of the microtubule
(MT) network that controls the polarized transport of axis determinants. A Combination of
quantitative 3D live imaging and laser ablation-mediated force analysis reveal that nuclear positioning
is ensured with an unexpected level of robustness. We show that the nucleus is pushed to the oocyte
antero-dorsal cortex by MTs and that its migration can proceed through distinct tracks. Centrosomeassociated MTs favour one migratory route. In addition, the MT-associated protein Mud/NuMA that
is asymmetrically localized in an Asp-dependent manner at the nuclear envelope hemisphere where
MT nucleation is higher promotes a separate route. Our results demonstrate that centrosomes do
not provide an obligatory driving force for nuclear movement, but together with Mud, contribute to
the mechanisms that ensure the robustness of asymmetric nuclear positioning.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 103
Paul Marcoux
POSTER P46
Paul Marcoux, Cloé Schuster, Antoine Ducuing, Muriel Grammont and Stéphane Vincent
ENS, Lyon, France
Morphogenetic functions of JNK and DPP at various stages
of Drosophila development
J
NK and DPP form a feed-forward loop that controls leading edge specification during Drosophila
dorsal closure: JNK activates DPP expression and both pathways are required to induce target
gene expression and cell differentiation. Interestingly several targets of this network motif are
expressed in tissues that undergo dramatic morphogenetic changes and where both JNK and DPP
are active. First, the microtubule-binding molecule Jupiter displays a striking striped expression in
the peripodial epidermis of the wing imaginal disc. Second, the actin organizer Zasp52 is expressed
in centripetal cells during their collective cell migration in the ovaries. Here we report the functional
relationships between these components and discuss the implications of the involvement of this
Gene Regulatory Network in the regulation of specific morphogenetic events.
104 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Tamas Matusek
POSTER P48
Tamas Matusek, Tanvi Gore, Gisela D’Angelo, Cécile Giordano,
Thomas Tognacci and Pascal Thérond
UNS, Inserm, CNRS, France
Role of the small GTP-ase Rab8 in the establishment
of Hedgehog long-, and short-range activity
I
ntroduction: Hedgehog (Hh) morphogen secretion and signaling have essential roles in defining cell
fate during development as well as maintaining stem cells in various tissues like the reproductive
system or the intestine. Understanding how Hh, and other morphogens, reach it’s targets at short
and long distance is a key question we are trying to resolve. Hh trafficking within its place of production
is essential for proper morphogen secretion and gradient establishment. In Drosophila imaginal disc,
Dynamin and Dispatched-dependent endocytosis prepares Hh for its final release either at the apical
pole (for its long-range activity) or the basal pole (to induce short-range targets) of the producing
cells (Ayers et al., Dev. Cell 2010; D’Angelo et al., Dev. Cell 2015). Apical secretion of Hh is dependent
on the fast recycling machinery involving the Rab4 small GTPase, while basal rerouting and secretion
is hypothesized to be regulated by the Hh coreceptors Interference Hedgehog (Ihog) and Brother of
Ihog (Boi; Bilioni et al., Dev. Biol. 2013).
R
esults: In a screen to find novel members of the Hh trafficking pathway, we have found that
absence of the small GTPase Rab8 affects Hh secretion and target gene expression. We
have developed rab8 knock-out animals and found that, in absence of Rab8, Rab4 and Ihog
distribution were affected. These changes were associated with a simultaneous change of short and
long range Hh target expressions. Additionally we observed a shift of Hh subcellular distribution from
a predominant apical distribution to a more basolateral one. We are currently assessing whereas
Rab8 changes directly the secretion of Hh from apical to basal, or changes its recycling route from
one cellular pole to the other
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 105
Christel Moog-Lutz
POSTER P50
Christel Moog-Lutz1,2, Arnaud Métais1,2, Armelle Melet1,2,3, Sandrine UttenweilerJoseph1,2, Isabelle Lamsoul1,2, Pierre G. Lutz1,2
1 CNRS; IPBS (Institute of pharmatology and structural biology);
Toulouse, France
2 Toulouse University ; UPS; IPBS; F-31077 Toulouse, France
3 Paris Descartes University; Paris, France
The ASB2α-Filamin A axis is essential for cytoskeletal remodeling
during mouse heart development
V
ertebrate heart morphogenesis relies on cardiac progenitors and on the assembly of the
contractile sarcomere apparatus of cardiomyocytes. Little is known about the mechanisms
that regulate actin cytoskeleton remodeling during cardiac cell differentiation. We are
interested in ASB proteins (Ankyrin repeat-containing protein with a Suppressor of Cytokine Signaling
box) that act as substrate-recognition modules of E3 ubiquitin ligase complexes. We demonstrated
that ASB2α and ASB2β isoforms encoded by the ASB2 gene are the specificity subunits of E3 ubiquitin
ligase complexes and trigger polyubiquitylation and proteasome-mediated degradation of the actinbinding protein filamins. We show that ASB2α plays an essential role in mouse heart development.
Importantly, ASB2α-mediated degradation of the actin-binding protein filamin A marks a previously
unrecognized intermediate step in cardiac cell differentiation characterized by cell shape changes
and actin cytoskeleton remodeling. We further establish that in the absence of ASB2α, myofibrils
are disorganized and that heart beats are inefficient, leading to embryonic lethality. These findings
identify ASB2α as an unsuspected key regulator of cardiac cell differentiation and shed light on the
molecular and cellular mechanisms determining the onset of myocardial cell architecture and its link
with early cardiac function.
106 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Pauline Nauroy
POSTER P52
P. Nauroy1, S. Hughes1, J. Chlasta2, A. Guiraud1, M. Malbouyres1, B. Gillet1,
M. Grammont2, E. Lambert1, A. Naba3 and F. Ruggiero1
1. Institut de Génomique Fonctionnelle de Lyon, France
2. LBMC, ENS, France
3. ENS Lyon / CNRS UMR5242/39 / Lyon University, France
4 Department of Physiology & Biophysics University of Illinois at Chicago /
College of Medicine, Chicago, USA
Extracellular matrix gene expression profile of regeneration reveals
an unexpected regulatory role of Collagen XIV in the structure and
biomechanics of regenerating basement membrane
I
ntensive research has been carried out on the mechanisms underlying tissue regeneration but the
role of extracellular matrix (ECM) during regeneration remains poorly explored.
We took the advantage of the adult zebrafish caudal fin model to determine the ECM players of
regeneration. With this aim, we established the first zebrafish matrisome described as the ensemble
of genes encoding ECM and ECM-associated proteins using an orthology approach. We then
performed a time-course RNA-sequencing analysis at different time points during regeneration
and we defined the matrisome of the regeneration. We then focused on the basement membrane
(BM) reconstruction, a structure that underlies epidermis and participates to skin biomechanics and
function. In addition to the “BM master components”, other ECM proteins actively contribute to the
formation of the epidermal BM. We highlight here the role of Collagen XIV (ColXIV-A).
W
e showed that ColXIV-A is highly expressed by the epidermal basal cell layer during fin
regeneration and is progressively deposited in the underlying BM zone. Knockdown
of ColXIV-A expression at the amputation site caused a significant thinning of the
regenerated BM. To further investigate changes in the topography of the reconstructed BM in
absence of ColXIV-A, we used atomic force microscopy (AFM). We showed that, in addition to a
marked decrease in thickness, the BM was also significantly stiffer compared to controls.
W
e then generated a zebrafish col14a1a knockout line using CRISPR/Cas9 technology. AFM
analysis of WT versus mutant fish confirmed that ColXIV-A plays a role in the BM formation
during regeneration. Analyzing the distribution of the elastic modulus values extracted
from AFM experiment revealed that the nanostructure of the col14a1a-/- regenerating BM is distinct
from WT suggesting that ColXIV-A is a key regulator of the BM structure by acting as a molecular
spacer. Preliminary results showed that Laminin deposition in the BM of reconstructing fin is delayed
in col14a1a-/- compared to WT confirming the involvement of ColXIV-A in BM structuration.
O
ur study represents the first documentation of gene expression profiles of regenerating BM
and underscores the importance of a minor component, ColXIV-A, in the BM structure and
biomechanics
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 107
Amanda Ochoa-Espinosa
POSTER P54
Amanda Ochoa-Espinosa, Stefan Harmansa, Emmanuel Caussinus, Markus Affolter
Biozentrum, University of Basel, Klingelbergstr. 50/70, Switzerland
Myosin II activity is not required for tracheal dorsal branch
elongation in Drosophila
T
he Drosophila tracheal system consists of an interconnected network of monolayered
epithelial tubes that ensures oxygen transport in the larval and adult body. During tracheal
dorsal branch (DB) development, DBs elongate as a cluster of cells, led by tip cells at the
front and trailing cells in the rear. Branch elongation is accompanied by extensive cell intercalation
and cell lengthening of the trailing stalk cells. While cell intercalation is governed by Myosin II
(MyoII)-dependent forces during tissue elongation in the Drosophila embryo leading to germ-band
extension, it remained unclear whether MyoII plays a similar active role during tracheal dorsal branch
elongation and intercalation. Here, we use a nanobody-based approach to selectively knock-down
MyoII in tracheal cells. Our data shows that despite the depletion of MyoII function, tip cells migration
and stalk cell intercalation (SCI) proceeds at a normal rate. Therefore, our data confirms a model in
which DB elongation and SCI in the trachea occurs as a consequence of tip cell migration, which
produces the necessary forces for the branching process.
108 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Anca Radu
POSTER P56
A. Radu1, S. Torch1 , F. Fauvelle2, P. Hainaut1, L. Larue3, C. Thibert1, M. Billaud4
1 Institute for Advanced Biosciences, CRI INSERM/UJF U1209 Grenoble Univ Alpes, Grenoble, F-38042, France,
2 Grenoble MRI Facility IRMage, INSERM/CEA U817 Grenoble Alpes University, Grenoble Neurosciences Institut Grenoble, France; Armed Forces Biomedical Research Institute,
3 Curie Institute, Normal and Pathological Development of Melanocytes,
CNRS UMR3347; INSERM U1021; Equipe Labellisée–Ligue Nationale
Contre le Cancer, Orsay, France,
4 Claude Bernard University Lyon I, INSERM 1052, CNRS 5286, Cancer center of Lyon, Lyon France
Lkb1 controls neural crest cells metabolism during glial
differentiation through non-essential amino acid levels
T
he neural crest cells (NCC) constitute a population of highly motile embryonic cells that give
rise to a broad array of derivatives including the peripheral nervous system and pigmented
cells. Using the Cre-LoxP system (Tyrosinase-Cre), we deleted in a subpopulation of murine
NCC the gene coding for Lkb1, a tumor suppressor kinase that regulates both metabolism and cell
polarity partly via the energetic sensor AMP-activated protein kinase (AMPK). Mutant mice exhibited
hypopigmentation, progressive hindlimb paralysis and died from intestinal pseudo-obstruction
before the sixth postnatal week. In the intestine, the interconnected nervous plexuses that constitute
the enteric nervous system (ENS) were correctly formed during the development but degenerated
postnatally. Sciatic nerves showed a deficit in axonal sorting, myelination and neuronal loss. These
defects were due to a lack of Schwann cell (SC) differentiation that retained expression of immature
markers, over-proliferated and displayed cell polarization defects. At the molecular level, the nutrientsensing mTOR pathway was upregulated in sciatic nerves in the absence of Lkb1, and the spatial
organization of mitochondrial network in SC as well as the metabolite profile of sciatic nerves were
altered. By using neural crest stem cells that can be committed in glial lineage, we demonstrated
that the defect of glial cell differentiation in the absence of Lkb1 was causally linked to an impaired
mitochondrial respiration and deregulated levels of non-essential amino acids (NEAA).
R
A
emarkably, reverting NEAA levels in vitro rescued glial differentiation and treatment of Lkb1deficient mice with 5-aminoimidazole-4-carboxyamide (AICAR), a metabolic agonist of AMPK
able to revert metabolic disorders, improved hind limb and digestive motricity.
ltogether, these findings highlight the crucial role of Lkb1 metabolic signaling in neural crest
derivatives, thereby suggesting that perturbations of Lkb1 pathway may contribute to the
aetiology of neurocristopathies.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 109
Mélanie Roussat
POSTER P58
Frédéric BONNET, Eric AGIUS, Sophie BEL-VIALAR, Fabienne PITUELLO
Max Planck Institute, Dresde, Germany
Biology and Development Center Toulouse, France
Function of a cell cycle regulator, the CDC25B phosphatase,
in Vertebrate neurogenesis
A
major challenge confronting the developing embryo is to generate the appropriate number
of neurons to build a functional central nervous system. This involves tight regulation
between proliferation and differentiation during the course of neurogenesis. A deregulation
of this balance can lead to neurodevelopmental disorders, such as microcephaly, when the pool of
progenitor is depleted due to precocious neuronal differentiation, or tumors growth if there is an
excess of proliferation. Accumulating data underline the role of cell cycle regulator in this process.
Using the chick as a model, our team recently showed that the phosphatase CDC25B, a well-known
regulator of the G2/M transition, promotes neuron production in the developing spinal cord (Peco et
al., 2012; Bonnet et al., in preparation). In addition, CDC25B has been shown to be deregulated in a
MCPH1 microcephaly model (Gruber et al., 2011). All together these data suggest that CDC25B could
be involved in the control of neurogenesis in the developing cortex. Our objective is now to determine
if CDC25B plays a rule in cortical development and growth. To this aim, we established and validated
a mouse genetic model, in which CDC25B is specifically invalidated in neural progenitors and we just
started to explore CDC25B function during corticogenesis
110 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Maleaume Soulard
POSTER P60
Maleaume Soulard, Anne Pélissier-Monier, Simon Marques and François Payre
UMR 5547 CNRS / Paul Sabatier University, France
Of the importance of temporally segregating cell proliferation and
differentiation during epidermal cells development
I
I
t is widely accepted that, in a developing tissue, cells first proliferate to yield the right number, and
then differentiate to acquire their function. Have these processes to be strictly sequential? What
would happen, if these two events do not succeed each other but overlap?
n drosophila, the epidermal tissue of adult thorax is formed during metamorphosis after several
waves of cell proliferation and one wave of terminal differentiation during which cells form an
actin-rich apical extension. Pioneer work demonstrates the essential role of the transcription
factor Shavenbaby (Svb) for the terminal differentiation of epidermal cells. Svb protein is present in
a long repressor form during cell proliferation and then processed in a shorter active form allowing a
synchronous differentiation of the tissue. Using a clonal analysis, we are able to modify behavior of
a small cell population by controlling the transcriptional activity of Svb. We notably observed, when
differentiation is prematurely induced in still proliferating cells, a decrease in cell number coupled
with increases in cell and nucleus sizes. These data suggest that premature differentiation impairs
cell proliferation and/or cytokinesis in epidermal cells. Our model is adapted to unravel which cellular
and molecular mechanisms are perturbed when cell proliferation and differentiation are no longer
temporally coordinated.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 111
Chantal Thibert
POSTER P62
AG Radu1, S. Torch1, F. Fauvelle2, P. Hainaut,1 L. Larue3, C. Thibert1, M. Billaud4
1 Institute for Advanced Biosciences, CRI INSERM/UGA U1209 Grenoble Alpes Univ, Grenoble, France
2 Grenoble MRI Facility IRMage, INSERM/CEA U817, Grenoble Alpes Univ
Grenoble Neurosciences Institut Grenoble, France; Armed Forces Biomedical Research Institute,
3 Curie Institute, Normal and Pathological Development of Melanocytes, CNRS UMR3347; INSERM U1021; Equipe Labellisée–Ligue Nationale Contre le Cancer, Orsay, France,
4 Claude Bernard University Lyon I, INSERM 1052, CNRS 5286,
National Cancer league Lyon, Lyon France
Lkb1 controls neural crest cells metabolism during glial
differentiation through non-essential amino acid levels.
T
he neural crest cells (NCC) constitute a population of highly motile embryonic cells that give
rise to a broad array of derivatives including the peripheral nervous system and pigmented
cells. Using the Cre-LoxP system (Tyrosinase-Cre), we deleted in a subpopulation of murine
NCC the gene coding for Lkb1, a tumor suppressor kinase that regulates both metabolism and cell
polarity partly via the energetic sensor AMP-activated protein kinase (AMPK). Mutant mice exhibited
hypopigmentation, progressive hindlimb paralysis and died from intestinal pseudo-obstruction
before the sixth postnatal week. In the intestine, the interconnected nervous plexuses that constitute
the enteric nervous system (ENS) were correctly formed during the development but degenerated
postnatally. Sciatic nerves showed a deficit in axonal sorting, myelination and neuronal loss. These
defects were due to a lack of Schwann cell (SC) differentiation that retained expression of immature
markers, over-proliferated and displayed cell polarization defects. At the molecular level, the nutrientsensing mTOR pathway was upregulated in sciatic nerves in the absence of Lkb1, and the spatial
organization of mitochondrial network in SC as well as the metabolite profile of sciatic nerves were
altered. By using neural crest stem cells that can be committed in glial lineage, we demonstrated
that the defect of glial cell differentiation in the absence of Lkb1 was causally linked to an impaired
mitochondrial respiration and deregulated levels of non-essential amino acids (NEAA).
R
A
emarkably, reverting NEAA levels in vitro rescued glial differentiation and treatment of Lkb1deficient mice with 5-aminoimidazole-4-carboxyamide (AICAR), a metabolic agonist of AMPK
able to revert metabolic disorders, improved hind limb and digestive motricity.
ltogether, these findings highlight the crucial role of Lkb1 metabolic signaling in neural crest
derivatives, thereby suggesting that perturbations of Lkb1 pathway may contribute to the
aetiology of neurocristopathies.
112 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Mathilde Toch
POSTER P64
Mathilde Toch, Audrey Harris1, Gauhar Masgutova1, Vincent Rucchin1
and Frédéric Clotman1
1 Laboratory of Neural Differentiation, Institute of Neuroscience,
Université Catholique de Louvain, Brussels, Belgium
Targets and mechanisms of action of the Onecut transcription factors in
the diversification of spinal motor neurons during embryonic development
D
uring embryonic development, spinal motor neurons (MNs) diversify into different subsets
characterized by distinct molecular identity, localization and connectivity. The diversification
of MN is controlled by several transcription factors, including Onecut factors. Onecut factors
are described as transcriptional activators that regulate several aspects of neural development in the
encephalon and in the spinal cord. They control the diversification of MNs by regulating directly the
expression of the Isl1 gene. However, other targets of the Onecut factors in MN are unknown and the
understanding of the mechanisms that regulate the diversification of these cells remains only partly
deciphered.
H
ere, using results of microarray experiments that compared the transcriptome of control
and of Onecut mutant spinal cords, we identified two genes downstream of Onecut factors
in MN, Pou2f2 and Nkx6.2. In mutant, we observed an increase in the number of MN that
contain Pou2f2 at each level of spinal cord. Furthermore, in contrast to control embryos wherein
Nkx6.2 expressed in a subset of MN of the Lateral Motor Column (LMC), we observed in the mutant
an expansion of Nkx6.2 expression to all neurons of the LMC. Thus, Onecut factors restrict, likely
indirectly, the expression of Pou2f2 and Nkx6.2 in the developing MN.
I
n contrast, Onecut factors directly stimulate the expression of the MN determinant Isl1. Whether
known cofactors of the Onecut proteins, namely CBP, p300/pCAF and PGC-1, are involved in this
process remains unsolved. Using chromatin immunoprecipitation, we observed that CBP, p300
and PGC-1 are preferentially bound, as Onecut proteins, to the CREST2 enhancer of Isl1. Using coelectroporation of chicken embryonic spinal cord, we demonstrated that inhibition of CBP and p300
activity prevented the induction of Isl1 expression by the Onecut factors. Taken together, these data
suggest that these cofactors may cooperate with Onecut factors for the regulation of Isl1 expression
MN.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 113
Patrick Torbey
POSTER P66
Patrick Torbey, Elodie Thierion, Samuel Collombet, Carole Desmarquet,
Patrick Charnay, Pascale Gilardi-Hebenstreit
ENS PSL Research University, CNRS, Inserm, France
Bilogy institute of ENS (IBENS), Paris, France
Cooperation of multiple enhancers for Krox20 regulation
in vertebrate hindbrain and their evolutionary divergence
D
uring vertebrate development, the hindbrain is segmented into rhombomeres (r). The
transcription factor Krox20 (Egr2) governs the specification of r3 and r5. Three enhancers of
Krox20: A, B and C have been so far identified in mice and orchestrate two phases in Krox20
expression: initiation and autoregulation. Element A is required for Krox20 autoregulation in r3 and
r5. Element C cooperates in cis with A and is required for autoregulation in r3. In order to decipher
the initiation and obtain a more comprehensive view of Krox20 regulation, we have performed an
exhaustive identification and functional characterization of all regulatory elements in zebrafish
and compared them with the mice elements, giving us an evolutionary understanding of this cisregulation in vertebrates.
W
I
e identified zebrafish elements A, B, C and 3 previously un-identified enhancers: D, E and
F. We have generated stable transgenic zebrafish lines and studied their kinetic and profile
of activity. We analysed their function by in vivo deletions, using the CRISPR/Cas9 system.
n zebrafish, 3 elements, A, D and E cooperate for krox20 autoregulation, whereas in mice, the sole
inactivation of element A abolishes Krox20 autoregulation. Deletion of zebrafish element C does not
seem to affect krox20 regulation, while the same deletion in mice leads to a loss of autoregulation
in r3. Zebrafish element B contributes to initiation in r5. Finally, element F is necessary for initiation
of krox20 in r3 in zebrafish; the deletion of its mice ortholog by CRISPR/Cas9 injection also results in
defects in Krox20 initiation in r3.
T
his study reveals the complex activity, function and interaction of many cis-regulatory
elements, as well as their divergence during evolution, leading to the precise and conserved
expression pattern of Krox20 in vertebrate hindbrain.
114 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Yusuke Toyama
POSTER P68
Yusuke Toyama, Zijun Sun, Christopher Amourda, Murat Shagirov,
Yusuke Hara, Timothy E. Saunders
Mechanobiology Institute, Singapore
3D cell shape changes drive tissue elongation
T
hroughout development, tissues undergo complex morphological changes, resulting from an
integration of cellular mechanics that evolve over time and in three dimensional space. During
Drosophila germ band extension (GBE), cell intercalation is the key mechanism for tissue
extension, and the associated polarized apical junction remodeling is driven by myosin-dependent
contraction. However, the contribution of the basolateral cellular mechanics to GBE remains poorly
understood. Here, we characterize how cells coordinate their shape and movement from the apical to
the basal side during rosette formation, a hallmark of cell intercalation. In contrast to apical rosette,
which is driven by polarized actomyosin contraction, basolateral rosette formation is driven by cells
mostly located at the most dorsal/ventral part of the rosette cluster (D/V cell). These cells exhibit
actin-rich wedge-shaped basolateral protrusions and migrate towards each other. Surprisingly, the
formation of basolateral rosettes precedes that of the apical rosettes. Impeding the acto-myosin
contractility affects the dynamic of basal rosette formation but does not prevent the formation of basal
rosettes. This indicates that the establishment of basal rosettes is independent of apical contractility.
Instead, by selectively blocking Rac activity within a D/V cell, we show that Rac-dependent protrusive
motility is required for basal rosette formation. Furthermore, by using an RNAi screen we identified
a tyrosine-protein kinase as a critical component in basal rosette formation, where an inhibition of
this tyrosine kinase leads to abnormal basal intercalation but retains apical rosette formation and
eventually results in delayed GBE. Our data show that in addition to apical contraction, active cell
migration driven by basolateral protrusions plays a pivotal role in rosette formation and contributes
to Drosophila GBE.
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Daan Van Den Brink
POSTER P70
DM van den Brink(1), A. Cubizolle (2), G. Chatelain (1), F. Napoletano (1),
M. Brunchault (1), P. Dourlen (3), P Brabet (2), B Mollereau
LBMC, CNRS UMR5239, ENS Lyon; (2) Neurosciences Institute of Montpellier, France
INSERM U1051, Montpellier University; (3) Epidemiology and Public HEALTH Unit
Inserm-U1167, Institut Pasteur de Lille, France
Non cell-autonomous role for glial Lipid Droplets
in photoreceptor survival in Drosophila and mice
S
creening for new retinopathy-related genes, we identified Fatty acid transport protein (Fatp) to
be required for photoreceptor survival in Drosophila (Dourlen et al. PLOS Genetics 2012). This
protein exhibits close homology to a family of human Fatp’s that are thought to be involved in
the cellular import of fatty acids. Fatp-mutant retina display a progressive decrease in visual function
followed by degeneration of photoreceptors. This phenotype can be rescued by re-expressing either
Drosophila or human Fatp1 in photoreceptors.
H
W
owever, we observe that when Fatp is overexpressed ubiquitously in the eye this negatively
affects the glia-like pigment cells. In this study we set out to identify the mechanism
underlying this degeneration.
e find that increasing Fatp-expression in the eye leads to alterations in (phospho)lipid
profiles, restricted to particular classes. We can observe changes directly by visualising
the incorporation of fatty acids in intracellular lipid droplets. These structures are thought
of as stores for excess lipids or to function as a reserve pool, but have recently also been proposed
to be harmful to the cell. Using confocal microscopy, we see a reduction in their number in Fatp lossof-function and, inversely, a clear increase when Fatp is overexpressed. Interestingly, lipid droplets
mainly accumulate in glia-like pigment cells and not in the photoreceptors. This is confirmed on an
ultrastructural level by electron microscopy, where we also find evidence of direct crosstalk between
cell types. In addition we show that Fatp expressed in pigment cells has effects on mitochondrial
function within photoreceptors.
T
hese findings indicate that Fatp is important in maintaining the correct flux of fatty acids for
phospholipid synthesis and metabolism in the retina. Since Fatp is enriched in pigment cells,
we show that a crosstalk between these cells and photoreceptors is crucial for homeostasis
and photoreceptor survival.
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Lucie Vaufrey
POSTER P72
Lucie Vaufrey, Stéphanie Le Bras, Claude Prigent
IGDR, Cell Cycle Team, Rennes, France
When Aurora-A impacts Drosophila brain development
A
urora-A (AurA) is a major kinase playing various roles in cell cycle. It’s a well-known oncogene
and companies are developing drugs inhibiting its kinase activity. However, it has been shown
in different species that AurA can have a kinase independent role or act as a tumor suppressor
when its kinase activity is altered. This represents a problem for drugs development as inhibiting
AurA kinase activity only could lead to life threatening phenotypes. To address this dilemma, we are
carefully deciphering the phenotype of five different AurA mutant alleles, ranging from no protein to
kinase dead, in Drosophila central brain larval neuroblasts a model for tumorigenic study.
O
ne readout to define a tumor suppressor in this model is a brain overgrowth phenotype
associated to central brain neuroblasts over-proliferation. In our five mutants, brain size
appears normal during the first 96h of larval development. However, pupation which normally
occurs between 96 and 120h of larval development is delayed in AurA mutants (1 to 3,5 days) and
associated with increased larval size. In this “delayed” mutant larvae, brains are eventually bigger
than wild-type controls. Furthermore, all AurA mutant central brains show a huge increased number
of cells positive for deadpan, a marker of neuroblast identity, even before the appearance of brain
over-growth phenotype. Additionally, optic lobe structure can’t be distinguished from central brain
which indicates a major defect in brain lobes development. In conclusion, AurA mutants with no
proteins, reduced or without kinase activity, share the same phenotype: 1) a pupation delay which
resembles Ecdysone pathway timing defects and could explain the enlarged brain phenotype; 2) a
brain lobe disorganization and an increased number of neuroblast-like cells. Ongoing experiments
are addressing AurA putative function in Ecdysone pathway and defining the temporal and cellular
origin of lobe brain disorganization and neuroblast-like cells.
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Alexis Weinreb
POSTER P74
Alexis Weinreb, Jean-Louis Bessereau
INMG, Claude Bernard University Lyon France
Analysis of activity-dependent synaptogenesis
in the nematode Caenorhabditis elegans
I
n various systems, activity of neurons or muscle can shape network connectivity and regulate
synaptic strength, thus providing the basis for learning and memory. The nematode Caenorhabditis
elegans is a powerful system to study the mechanisms of synapse formation and maintenance.
We chose to analyze the development of the 3 SAB motor neurons that are innervating muscles
in the head of the worm. In this system, it was shown that electrical silencing of the muscle cells
during development can regulate SAB morphology (Zhao and Nonet, Development, 2000). Using
fluorescently-tagged acetylcholine receptors (AChR), we observed SAB overgrowth and ectopic
synapse formation in unc-13 and unc-18 mutant worms where neuromuscular transmission was
disrupted. We could confirm that this effect is not due to the loss of movement because there is no
SAB overgrowth in unc-54/Myosin Heavy Chain B mutants that are completely paralyzed. To silence
the electrical activity of muscle cells, we specifically expressed in muscles the Drosophila HisCl1
histamine-gated chloride channel and the TWK-18 temperature-dependent potassium channel. In
both conditions, inhibition of muscle cell activity causes SAB overgrowth, suggesting that retrograde
factor(s) control SAB development. We could further pinpoint a critical developmental window at
the first larval stage during which SAB development is plastic. In addition, we demonstrated that
chronic – but not acute – increase of synaptic transmission through acetylcholinesterase inhibition
leads to a decrease in the number of synaptic AChRs, suggesting an activity-dependent regulation
of AChR number during development. Through a transcriptomic approach, we expect to find genes
involved in the overgrowth of the SAB and the regulation of AChR number. We are using RNA-Seq to
detect genes differentially expressed upon electrical manipulation of the muscle cells. In parallel, we
are using the tools that we developed to better define the conditions leading to SAB overgrowth and
AChR downregulation, as well as testing a number of candidates genes.
118 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Zhiwen Zhu
POSTER P76
Zhiwen Zhu, Yongping Chai and Guangshuo Ou
School of Life Sciences, Tsinghua University, Beijing 100084, China
Spatiotemporal Orchestration of Tyrosine Kinase and Phosphatase
Maintains Cell Polarity during Neuroblast Migration
D
irectional cell migration requires the establishment and maintenance of the highly polarized
actin cytoskeleton. Despite remarkable progresses in understanding polarity establishment,
relatively little is known regarding the maintenance of a protrusive leading edge and a
contractile rear. Using the Caenorhabditis elegans Q neuroblast as our experimental system, we
have recently identified a MIG-13-WAVE/WASP-Arp2/3-dependent signaling pathway underlying Q
cell anterior migration (Wang et al., PNAS, 2013; and Zhu et al., Dev Cell, 2016). Here we report that
a tyrosine kinase SRC-1 phosphorylates MIG-13 and promotes its activity in the leading edge. By
imaging SRC-1 and MIG-13 in the GFP-knock-in animals, we find that SRC-1 and MIG-13 evenly
distribute along the entire plasma membrane. Essentially, our genetic screen isolated a receptorlike tyrosine phosphatase essential for the polarity maintenance in the migrating Q cells; and this
phosphatase is specifically enriched in the rear. We are conducting biochemical analysis to test
the model in which the antagonism between kinase and phosphatase on a single transmembrane
receptor ensures the polarity of the actin cytoskeleton throughout cell migration. Our finding also
highlights the importance of asymmetric localization of a phosphatase in cell polarization.
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120 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
POSTERS
SESSION 2
(Odd numbers)
- Friday 28th of April 12:30 - 03:30pm
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 121
122 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Ursula
ABAD
P01
Guillaume
BALAVOINE
P03
Flore
BEURTON
P05
Nadège
BONDURAND
P07
Sandra
CLARET
P09
Pénélope
DARNAT
P11
Jonathan
DEGOSSERIE
P13
Élodie
DESMARIS
P15
Emmanuel
GALLAUD
P17
Cécile
GIORDANO
P19
Amandine
GUERIN
P21
Alexandre
GUIRAUD
P23
Annaïg
HAMON
P25
Luke
HAYDEN
P27
Christine - Maria
HOREJS
P29
Julie
JOUETTE
P31
Karolina Uwantege
KABAYIZA
P33
Anaïs
KHUONG
P35
Gabriel
KRASOVEC
P37
Lilia
LADDADA
P39
Julien
LAUSSU
P41
Morgane
LOCKER
P43
Gauhar
MASGUTOVA
P45
Grégoire
MICHAUX
P47
Frédéric
MORET
P49
Gerry
NGANOU
P51
Sophie
PANTALACCI
P53
Leslie
RATIÉ
P55
Bechara
SAYKALI
P57
Ralitza
STANEVA
P59
Dong
TIAN
P61
Caterina
TOMBA
P63
Sakina
TORCH
P65
Camille
VACHON
P67
Aidamalia
VARGAS-LOWMAN
P69
Stéphane
VINCENT
P71
Xinyi
YANG
P73
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 123
Ursula Abad
POSTER P01
Sassi, Massimiliano; Traas, Jan
Laboratory Reproduction & Development of Plants, INRA, CNRS, ENS, UCB Lyon, France
Morphogenesis at the shoot apical meristem
T
he process of morphogenesis is driven by cell division and expansion, which are controlled in
a differential manner among cell types and tissues.
In plants, the dynamic and continuous production of organs is mainly localized at the
meristems. Above ground organs are produced by the shoot apical meristem (SAM). The initiation
of new organs in the SAM is triggered by the local accumulation of the hormone auxin. It is widely
accepted that auxin orchestrates the initiation of flower primordia by controlling a transcriptional
regulatory network. We study this process in the inflorescence of Arabidopsis thaliana. A central role
is given to the DNA-binding auxin response factor ARF5/MP. After its activation, ARF5/MP directly
induces the expression of LEAFY (LFY), AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6)
transcription factors necessary for the specification of floral identity and proliferative growth.
A
t the cellular level, the initiation of primordia depends entirely on regional growth rates and
growth directions. In plant cells, these processes are mainly regulated via modifications of the
cell wall, the extracellular matrix surrounding all cells. Consequently, the physical properties of
this m= atrix directly control morphogenesis. Auxin and its downstream targets are involved in these
processes, by activating changes in the dynamics of the cortical microtubules (CMT), which result
in changes in growth direction (Sassi et al., 2014). Auxin also slightly reduces tissue rigidity prior to
organ outgrowth in the SAM, which result in changes in growth rate (Braybrook and Peaucelle, 2013).
Thus, auxin and the transcriptional regulatory network integrate primordium initiation by regulating
the two local parameters of growth, rate and direction. Here we present evidence that this regulation
might also involve feedbacks where changes in growth parameters influence molecular regulation.
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Guillaume Balavoine
POSTER P03
B. Duygu Özpolat, Mette Handberg-Thorsager, Michel Vervoort, Florian Raible, Guillaume Balavoine
Jacques Monod Institute JCNRS / Sorbonne Paris Cité Univ Paris France;
Max F. Perutz Laboratories, University of Vienna, Austria; Max Planck Institute,
Dresden, Germany
Live-imaging tools for deciphering the segmentation oscillator
in a marine annelid
M
ost segmented animals form a body axis, either during embryogenesis or during postembryonic development, by posterior addition of segments. This process requires the
presence of a temporal oscillator at the posterior tip of the body. Such a «segmentation
clock» has already been well characterized in vertebrate embryos and discovered more recently in
some arthropods. We study the segmentation mechanisms in the marine annelid Platynereis, that
adds segments posteriorly throughout most of its life. Posterior elongation relies on specialized pools
of stem cells, called teloblasts, organized in a thin ring around the sub-terminal region of the body.
Preliminary results suggest that these teloblasts undergo periodic waves of asymmetric divisions,
each wave producing the progenitors necessary for a single additional segment. In order to precisely
monitor the biology of teloblasts throughout the life cycle of the worm, we are developing transgenic
tools in Platynereis:
1 - a FUCCI line that will allow following in real time the waves of teloblast divisions, confirming
their linkage to segmentation, demonstrating the occurrence of asymmetric divisions and testing the
action of the various signalling pathways on asymmetry and periodicity. Combined to RNAseq, it will
also permit the identification of sets of oscillating genes specific to teloblasts.
2 - a BRAINBOW line based on an inducible Cre-lox system that will allow stable sparse labelling of
cell lineages, as an ideal setup to trace putative stem cells and their descendants. Labelling of early
segmental progenitors will test the idea that each one contributes to a single segment and therefore
that the segmentation oscillator coincides with the teloblast cell cycle by itself.
3 - a beta-catenin fluorescent reporter line. Wnt signalling is a candidate signaling pathway for
teloblast regulation.
T
his study will provide crucial results for comparing all meristematic growth and segmentation
processes across metazoans.
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Flore Beurton
POSTER P05
Flore Beurton, Cécile Bedet, Matthieu Caron, Francesca Palladino, Jérome Govin,
Yohann Couté, David Cluet, Martin Spichty
Biology and cell modelisation laboratory of Lyon, Exploring the Dynamics of Proteomes
CEA Grenoble, France
Characterization of the SET1/MLL complexes in C. elegans
M
ethylation of histone H3 Lys4 (H3K4me) is associated with active transcription in all species,
and is catalyzed by highly conserved multiprotein complexes known as Compass in yeast
or SET1/MLL in mammal. Biochemical characterization of SET1/MLL complexes from
yeasts to mammals has shown that in addition to the catalytic SET1/MLL subunit, these complexes
share in common ASH2, RbBP5, WDR5 and DPY30 subunits. In addition, SET1 complex contain an
additional subunit, the CXXC Zinc finger protein CFP1. We have identified single homologs of all
subunits in C. elegans and shown that they contribute to global H3K4 methylation. The biochemical
composition of the complex, however, has not been described.
I
n order to purify the SET1 complex from C. elegans, and identify additional associated proteins, we
undertook a proteomic approach on embryos derived from animals expressing either tagged CFP1 or WDR-5. Immunoprecipitation experiments followed by tandem MS/MS identified all common
subunits of the SET1/MLL complexes with both CFP-1 and WDR-5. In addition, we identified unique
subunits of SET1 and MLL related complexes.
F
urthermore, new candidates were also identified as top hits in WDR-5::HA and CFP-1::GFP
immunoprecipitation experiments. I will present data on the biochemical, molecular and
genetic characterization of the most interesting candidates isolated by this approach, thereby
providing novel insight on the function of SET1 in a developmental context.
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Nadège Bondurand
POSTER P07
Yuli Watanabe1,2
1 INSERM, U955, Equipe 6, Créteil, France;
2 Paris-Est University, Medical School Créteil, France;
3 Department of Cell Biology, Erasmus University Medical Center, Rotterdam, Netherlands;
4 Laboratory of Molecular Biology (Celgen), Department of Development
and Regeneration, KU Leuven, Belgium.
Differentiation of Mouse Enteric Nervous System Progenitor Cells is
Controlled by Endothelin 3 and Requires Regulation of Ednrb by SOX10
and ZEB2
M
aintenance and differentiation of progenitor cells in the developing enteric nervous system
(ENS) are controlled by molecules such as the signaling protein endothelin 3 (EDN3), its
receptor (the endothelin receptor type B, EDNRB), and the transcription factors SRY-box 10
(SOX10) and zinc finger E-box binding homeobox 2 (ZEB2). However, cross regulation between these
different molecules remains unclear.
H
ere, we used several approaches to examine the potential co-operation of ZEB2 and the
EDN3/EDNRB signaling pathway during enteric neurogenesis. Firstly, we found an altered
response to EDN3 in enteric progenitor cultures that were heterozygous for the Zeb2
mutation (referred as Zeb2Δ/+ EPCs) compared to EPCs that expressed two copies of wild-type
Zeb2 (Zeb2+/+, referred as wild-type EPCs). In vitro gene regulation studies, combined with rescue
experiments in EPCs cultures and phenotype analysis of Zeb2;Edn3 or Zeb2;Ednrb double mutants
mouse embryos subsequently allowed us to demonstrate the synergistic transcriptional regulation
of EDNRB by SOX10 and ZEB2, as well as the essential role of the SOX10/ZEB2/EDN3 “triade” in
controlling the differentiation status of enteric neural crest cells. These findings expand our knowledge
of the molecular mechanisms underlying maintenance of multi-potential ENS progenitors, leading to
a better understanding of the cellular bases of Hirschsprung disease.
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Sandra Claret
POSTER P09
Sandra Claret, Julie Jouette, Antoine Guichet
Jacques Monod Institute, Paris, France
Dynein-mediated transport and membrane trafficking
control PAR3 polarised distribution
T
he scaffold protein PAR3 and the kinase PAR1 are essential proteins that control cell polarity.
Their precise opposite localisations define plasma membrane domains with specific functions.
PAR3 and PAR1 are mutually inhibited by direct or indirect phosphorylations, but their fates
once phosphorylated are poorly known. Through precise spatiotemporal quantification of PAR3
localisation in the Drosophila oocyte, we identify several mechanisms responsible for its anterior
cortex accumulation and its posterior exclusion. We show that PAR3 posterior plasma membrane
exclusion depends in an initial step on PAR1 and an endocytic mechanisms relying on RAB5 and
PI(4,5)P2. Microtubules and the dynein motor, through vesicular trafficking, are further required
for PAR3 transport to the anterior cortex before it is released by unloading from dynein through
the action of the IKK-related kinase, IKKε. Altogether our results point to a connection between
membrane trafficking and dynein- mediated transport to sustain PAR3 asymmetry. 128 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Pénélope Darnat
POSTER P11
Pénélope Darnat (1) , Jérémy Sallé (2), Agnès Audibert (1) and Michel Gho (1)
(1) IBPS - Development Laboratory, (2) Jacques Monod Institute
Coordination between cell proliferation and planar cell polarity in
asymmetric cell divisions of the Drosophila bristle precursor cells
D
evelopment and morphogenesis of multicellular organisms rely on a tight coordination between
cell proliferation, planar cell polarity and cell determination. Defects in one of these processes
can induce defects in the other two and lead to pathologies such as cancer. The nature of
the mechanisms by which these processes crosstalk remains barely understood. My project aims
to study how proteins involved in cell cycle interact with those regulating planar cell polarity. These
links are studied in asymmetric cell divisions, which generate cell fate diversity, through polarization
of precursor cells. Thus, spatial and temporal coordination between the mitotic spindle orientation
and localization of cell fate determinants, both relative to the polarity axis is critical for the generation
of daughter cells with two different fates.
U
sing as a model system the Drosophila bristle lineage, which generates the mechanosensory
organs via asymmetric cell divisions, we have shown that CyclinA (CycA), a cyclin essential
for the entry into mitosis, acts as a bridge between cell proliferation and planar cell polarity.
Indeed, we have observed that a pool of CycA was asymmetrically localized at the apical-posterior
cortex of the precursor cells during mitosis. This particular CycA asymmetric localization was
abolished when the planar cell polarity was disrupted in frizzled (fz) and dishevelled (dsh) mutants.
Using a Proximity Ligation Assay (PLA), we have also displayed the physical interaction between
CycA and Frizzled. More importantly, cell divisions are misoriented under a cycA loss of function
condition as well when CycA was ectopically localized at the cell cortex.
T
ogether, these data unravel the involvement of this asymmetric CycA localization in cell
division orientation and, highlight a new function never observed in other systems for this cell
cycle factor.
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Jonathan Degosserie
POSTER P13
Jonathan Degosserie, Christophe E. Pierreux
Duve Institute and Université catholique de Louvain, Brussels, Belgium
Role of Extracellular Vesicles in Thyroid Organogenesis
I
ntercellular communication is essential for biological processes such as cellular differentiation and
pathological processes such as cancer. Our lab has recently shown that reciprocal communication
between epithelial and endothelial cells is of major importance for pancreatic and thyroid
organogenesis during murine development. In the developing thyroid, epithelial cells first secrete
huge amount of VEGFa that stimulates recruitment of endothelial cells. In turn, recruited endothelial
cells invade the thyroid epithelial bud and induce thyroid progenitors to reorganize and form thyroid
follicles.
U
sing an original ex-vivo thyroid culture system that faithfully reproduces in vivo thyroid
development and follicle formation, we demonstrated that medium conditioned by endothelial
cells stimulate folliculogenesis. In addition, this folliculogenic activity could be further purified
by high-speed centrifugation of the conditioned medium in a sedimentable material. Morphological
and biochemical characterization of this material lead us to identify round shape membrane structure
with an average size of 100nm and a density of 1,10g/mL corresponding to extracellular vesicles
(EVs). EVs have been recently identified as sophisticated vehicles, containing soluble proteins and
nucleic acids, and involved in short and long distances communication processes.
M
ass spectrometry analysis of the EVs uncovered the presence of specific vesicular markers
as well as of abundant laminin alpha1, beta1 and gamma1 peptides. EVs purified from
endothelial cells pre-infected with laminin alpha1 shRNA have no folliculogenic activity,
indicating that laminin present in the sedimentable material is required for the folliculogenic activity.
Our current working hypothesis is that laminins are important for EVs targeting and incorporation in
thyroid progenitor cells.
130 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Elodie Desmaris
POSTER P15
Elodie Desmaris, Amandine Saulnier, Marc Keruzore, Leslie Ratié, Sarah De Clercq, Eric Bellefroid
IBMM-ULB, France
Dmrt3 and Dmrt5 act together in telencephalon
dorso-ventral patterning
T
he embryonic mammalian telencephalon is divided into dorsal and ventral sectors that have
distinct molecular features and generate different essential structures.
The dorsal telencephalon, also designed pallium, develops as a neuroepithelium that gives
mostly rise to cerebral cortex tissue known to be the seat of higher cognitive functions. The embryonic
ventral telencephalon, also designed subpallium, is composed of the ganglionic eminences which
generate basal ganglia nuclei, basal forebrain limbic system structures, and some cortical interneurons.
The initial subdivision of the ventral and dorsal telencephalon is regulated by morphogens such as
sonic hedgehog and several transcription factors, among which Pax6 in the cortex and Gsx2 in the
subpallium. Elucidation of all mechanisms that govern the telencephalon development will allow a
better comprehension of several associated diseases such as schizophrenia, lissencephalia.
T
ranscription factors are known to play an essential role in neural progenitors proliferation,
maintenance, differenciation, as well as in aeralization and regionalization processes. Dmrt
genes are coding for a family of evolutionnary conserved transcription factors caracterised by
the specific DM DNA binding domain. Among them, Dmrt3, Dmrt4, Dmrt5 are expressed in gradient
in the developing dorsal telencephalon.
D
mrt3 and Dmrt5 are expressed within cortical progenitors in the same high caudomedian to
low rostrolateral gradient. Laboratory results have already shown that both are important
for caudomedial cerebral cortex development and notably for the visual area. Now we have
shown that these two apparented transcription factors cooperate for the dorso-ventral patterning.
The molecular mechanisms of the synergy between Dmrt3 and Dmrt5 remain to be precised. To do
so we have compared Dmrt3 ;Dmrt5 double KO mice to WT ones and also have done analysis of the
overexpression by in utero electroporation or using trangenic mouse line. Further investigations will
allow us to identify the targets and other molecular partners of these to factors.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 131
Emmanuel Gallaud
POSTER P17
Emmanuel Gallaud, Anjana Ramdas Nair, Priyanka Singh, Tri T. Pham,
David Salvador Garcia, Alexia Lyonton-Ferrand, and Clemens Cabernard
Biozentrum, University of Basel, Switzerland
Resolving centrosome asymmetry establishment
in Drosophila neuroblasts using 3D-SIM
C
entrosomes, the microtubule organizing centers (MTOCs) of metazoan cells, are intrinsically
asymmetric; they differ in age, molecular composition and activity. In stem cells, centrosomes
can segregate non-randomly, and the stem cell retains either the older or younger centrosome.
Biased centrosome inheritance has been proposed to be correlated with stemness. However, the
mechanisms underlying non-random centrosome segregation and its function remain elusive.
W
e used 3D Structured Illumination Microscopy (3D-SIM) to study the onset and
mechanisms of centrosome asymmetry in Drosophila neuroblasts, the neural stem
cells of the developing brain. We found that in early interphase, centrosomes separate
and duplicate their cartwheel. Centrosomes are composed of a fully formed centriole throughout
interphase, serving as a template for the formation of the daughter centriole. In early mitosis, Ana-1
and Asterless (Asl) are loaded onto the daughter centriole, gradually enriching along mitosis. This
centriole-to-centrosome conversion generates a pair of fully formed centrioles at each pole of the
mitotic spindle. At telophase, centrioles disengage and will duplicate again in the following cell cycle.
N
ext, we analyzed the localization of asymmetric centrosomal markers such as Polo,
Centrobin (Cnb) and Plp (Pericentrin like protein). We used Asl intensity to assess centriole
age and found that Centrobin, a daughter centriole specific protein is initially localized on the
preexisting mother centriole but switches to the daughter centriole during mitosis. Similarly, Polo
and Plp also relocalize during mitosis. By telophase, Centrobin is labelling the daughter centriole
whereas Polo and Plp are enriched on the daughter and mother centriole respectively. Finally, lossof-function experiments suggest that Cnb and Wdr62 are critical components in the establishment
of centrosome asymmetry.
W
e propose that centriolar proteins switch from the mother centriole to the daughter with
distinct dynamics. This mechanism could potentially explain the conflicting observations
that some stem cells
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Cécile Giordano
POSTER P19
Cécile Giordano, Laurent Ruel, Pascal Thérond
CNRS UMR7277, Inserm U1091, UNS, Institute of Biology Valrose, France
Mechanisms leading to the activation of Hedgeho
g pathway in drosophila melanogaster
H
edgehog (Hh) is a morphogene that controls in a gradient-dependent manner cell differentiation
and patterning in both invertebrates and vertebrates. In Drosophila, the Hh signal transduction
is initiated by interaction of Hh with its receptor Patched that induces Smoothened (Smo)
activation. This leads to signal transmission to a cytoplasmic complex composed of five proteins:
the 3 kinases, Fused (Fu), G-protein receptor kinase homolog Gprk2 and protein kinase A (PKA), the
kinesin-like Costal2 and the transcription factor Cubitus interruptus (Ci). Differential regulation of the
Fu kinase activity is controlled by different levels of Hh signaling. Low magnitude of Smo activation
(PKA-dependent) induces a weak activation of Fu whereas high magnitude of Smo activation (GprK2dependent) triggers high levels of Fu activity. It still remains unclear how the Smo/Gpr K2/PKA complex
regulates differential activation of Fu in the Hh gradient. Using phospho-antibodies, kinase assays,
inmmuno-precipitations and BiFC (Bimolecular Fluorescence Complementation), I have analysed
the effect of different domains of Smo on the differential activation of Fu. I first demonstrated that
the last 59 amino acids of Smo (SmoC) interact with Fu and activate the signalosome complex
in vitro. Secondly, by using drosophila as genetic model, I have confirmed that SmoC protein acts
as a peptide activator of the Hh pathway. The expression of SmoC in vivo induces Hh signaling
during development, and genetic analysis demonstrates that the effect of SmoC is dependent on
endogenous Smo and GprK2 proteins. By using BiFC approach, I have demonstrated that Smo and
GprK2 form a complex with Fu. This project will be completed with the analysis of the conformational
changes present in the transduction complex which are responsible for full activation of the Fu kinase
that occurs upon Hh activation.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 133
Amandine Guerin
POSTER P21
A. Guerin, Martire D, J. McKey, P. de Santa Barbara and S.Faure
PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR, France
LIX1 regulates YAP1 activity and controls the proliferation
and differentiation of stomach mesenchymal progenitors
D
uring development, the digestive musculature arises from mesenchymal cells. In adults,
these cells can undergo oncogenic transformation. Because tumorigenesis often involves
the reactivation of developmental processes, a better understanding of the molecular
mechanisms driving digestive mesenchyme development could offer insight into altered mechanisms
in gastrointestinal cancers.
H
ere, we focused on the Limb Expression 1 (LIX1) gene. LIX1 is a 281 amino-acid protein.
Predictive in silico studies have shown that LIX1 has a double-stranded RNA-binding domain
such as DICER and DROSHA (unpublished data), suggesting that it could be involved in RNA
or miRNA processing. Using the chick embryo as a model organism, we demonstrated that LIX1
(Limb expression 1) specifically defines the population of mesenchymal progenitors, thus identifying
LIX1 as a marker of stomach mesenchyme immaturity. Furthermore, using in vivo gain- and loss-offunction approaches, we demonstrated that expression of LIX1 must be tightly regulated to allow finetuning of the transcript levels and state of activation of the pro-proliferative transcriptional coactivator
YAP1 to regulate proliferation rates of stomach mesenchymal progenitors and their differentiation.
Our data highlight dual roles for LIX1 and YAP1 and provide new insights into the regulation of cell
density-dependent proliferation, which is essential for the development and homeostasis of organs
(Mckey et al., BMC Biol, 2016). We evaluated the level of LIX1 transcripts in different cancer cell lines
and found a high level of LIX1 transcripts specifically in immature mesenchymal cells. Interestingly,
we found that the downregulation of LIX1 decreases proliferation and invasion of immature
mesenchymal cells in vitro suggesting that LIX1 have a crucial role in oncogenic malignancy. We
recently carried out a yeast two-hybrid screen using the human LIX1 protein as bait and identified
a tubulin-binding protein as a partner of interest for LIX1. Our work currently investigate to which
extend the interaction with this protein partner is important for LIX1 fonction in regulating digestive
mesenchymal physiopathology.
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Alexandre Guiraud
POSTER P23
Alexandre Guiraud1Nathalie Couturier1, Vladimir Buchman2, Anne-Cécile Durieux3, David
Arnould3, Emilie Christin1, Stéphane Janczarski4 Marc Bitoun5 and Vincent Gache1
1- U1217, UMR 5310, INMG, MNCA team, INSERM, CNRS,
Claude Bernard University Lyon France.
2- Cardiff University, School of Biosciences, Cardiff, United Kingdom.
3- Laboratory of Exercises Physiology, Lyon University, Saint Etienne, France.
4- UMR 5239, LBMC ENS Lyon-CNRS, France.
5- UM76, Pierre et Marie Curie University-Paris 6, France.
Myonuclear domains establishment in skeletal
muscle fibers formation implicates Sh3kbp1
C
entronuclear myopathies (CNM) are a group of congenital myopathies characterized by
skeletal muscle weakness, fatigability and atrophy. In affected muscles, myonuclei are
abnormally located at the center of muscle fibers instead of being at the periphery of cells.
Initially considered as a consequence of the pathology, myonuclear mispositioning has recently
emerged as one of the possible cause of the muscle defects observed in CNM. Nevertheless the
molecular machinery responsible for correct myonuclear positioning is not known yet.
I
ndeed during muscle differentiation, mononucleated myoblasts fuse together to form
multinucleated muscle fiber, within which nuclei are regularly distributed along the cell and at
its periphery. Thus, each myonucleus drives a limited portion of muscle fiber functionality, rising
the notion of myonuclear domain. To understand the establishment of myonuclear domains, we
performed a siRNA screen on potential cytoskeleton regulators to discover new actors involved
in myonuclear positioning. This screen identified Sh3kbp1 (SH3 domain kinase binding protein
1). Although Sh3kbp1 is a ubiquitously expressed adaptor protein, we showed that its expression
increases upon muscle differentiation and is reactivated during muscle regeneration in mouse
consistent with a role during muscle formation. Interestingly, we showed that Sh3kbp1 accumulates
progressively around myonuclei and at triads during the course of muscle differentiation in vitro and
in mouse muscle fibers in vivo. Sh3kbp1 knockdown using siRNA in primary myoblasts or stable
transfection of shRNA in C2C12 muscle cell line reveals that Sh3kbp1 is not involved in the onset
of muscle differentiation, but is required for the fusion and maturation of muscle fibers. Indeed its
absence induces an increased fusion capacity, associated with defects in T-tubules and myonuclear
domains establishment which are typical of CNM phenotype. Consistently, preliminary experiments
suggest that Sh3kbp1 could play a compensation role in a Dnm2 mouse model of CNM, probably
through its interaction with Dnm2.
A
ltogether our results show that Sh3kbp1 is a key new regulator of both T-tubules maturation
and myonuclear domains establishment, and identify Sh3kbp1 as a central player to better
understand CNM.
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Annaïg Hamon
POSTER P25
Annaïg Hamon1,2, Christel Masson-Garcia1,2,Juliette Bitard1,2, Elodie-Kim Grellier1,2, Linn
Gieser3 Jérôme E. Roger1,2 and Muriel Perron1,2
1 Paris-Saclay Institute of Neuroscience, CNRS, Paris Sud University,
Paris-Saclay University, Orsay, France
2 Center for study and Therapeutic Research in Ophtalmology
Retina France, Orsay, France
3 Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute,
National Institutes of Health, Bethesda, MD 20892, USA
Reactive gliosis and regeneration potential of Müller cells in the retina:
implication of the effector YAP of the Hippo signaling pathway
R
eactive gliosis and regeneration potential of Müller cells in the retina: implication of the effector
YAP of the Hippo signaling pathway
Annaïg Hamon1,2, Christel Masson-Garcia1,2,Juliette Bitard1,2, Elodie-Kim Grellier1,2, Linn
Gieser3 Jérôme E. Roger1,2 and Muriel Perron1,2
1 Paris-Saclay Institute of Neuroscience, CNRS, Univ Paris Sud, Université Paris-Saclay, Orsay, France
2 Centre d’Etude et de Recherche Thérapeutique en Ophtalmologie, Retina France, Orsay, France
3 Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of
Health, Bethesda, MD 20892, USA.
M
üller cells constitute the major glial cell type of the retina. These cells can undergo
reprogramming into a stem-like state upon appropriate stimulation. If such a process
sustains powerful regeneration abilities of some species, it is largely inefficient in mammals.
What impedes this potential still needs to be discovered. In pathological contexts, mammalian Müller
cells undergo reactive gliosis, a process known to have beneficial effects within the damaged tissue
but also detrimental effects preventing regeneration. Increasing our knowledge of the complex
molecular response of Müller cells to retinal degeneration is thus essential for the development of
promising new therapeutic strategies. To identify novel players acting in Müller glia response, we
focused our interest on the Hippo/YAP pathway, a crucial player in the field of stem cell biology and
regeneration. Analysis of RNAseq data revealed that the Hippo/YAP pathway is one of the main
signaling deregulated in a mouse model of photoreceptor degeneration. In particular, we found that the
effector of the pathway, YAP, specifically expressed in Müller cells, is strongly upregulated alongside
photoreceptor loss. The expression of YAP partner, TEAD1, and of Ctgf and Cyr61, two target genes
of the transcriptional YAP/TEAD1 complex, is also upregulated in a degenerative context. This data
uncovers for the first time a link between the Hippo/YAP pathway and Müller cell reactive gliosis. We
next generated Yap conditional knockout specifically in Müller cells. RNA-seq transcriptomic analysis
suggests that YAP regulates the maintenance of a non-reactive state in mouse Müller glia. Indeed,
in a degenerative retina, the absence of YAP in Müller cells leads to the upregulation of markers of
reactive gliosis, such as GFAP. On the other hand, a decrease in cell cycle genes and neurotrophic
factors is observed. All together, we propose a model where YAP would regulate the balance between
beneficial and detrimental effects of Müller cell response to injury. This provides novel insights into
the signaling network operating in Müller cells that could serve to identify new therapeutics to trigger
retinal regeneration.
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Luke Hayden
POSTER P27
Luke Hayden, Michalis Averof
ENS Lyon, France
Building a molecular clock to measure aging
in a regenerating limb-bearing
W
e are interested in the possible connection between the processes of regeneration and
aging. Aging is, at least partly, a molecular phenotype, reflected by the expression levels
of certain transcripts. Where organs or tissues have been amputated and subsequently
replaced by a new ones, is the replacement older or younger than the original? How can we build a
system that will allow us to reliably measure the molecular age of a sample? In order to tackle this
issue, we use as a model the regenerating limb of Parhyale hawaiensis, an amphipod crustacean.
I
n order to create a reliable measure of transcriptomic age, we have used transcriptomic datasets
from animals of differing ages to identify a large set of genes which are differentially expressed
with age. Having identified over 2000 differentially expressed genes, we used this set of transcripts
as a basis for the creation of a custom NanoString codeset, allowing the expression of these genes
to be examined in many samples and under varying conditions. These genes were chosen without
regard to their identities, providing an unbiased approach without prior assumptions.
W
e have identified a subset of these markers as representing a robust “molecular aging
signal’. We have examined this aging signal. We have identified changes in the degree
of transcriptomic noise with age. We have also examined how regeneration affects this
aging signal.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 137
Christine-Maria Horejs
POSTER P29
Christine-Maria Horejs, Jean-Philippe St.Pierre, Manuel López-Cabrera, Molly M Stevens
JP St.P and M.M.Stevens
Imperial College London; M L-C: Centro de Biología Molecular Severo Ochoa, CSIC,
Universidad Autónoma de Madrid, Spain
Basement membrane-cell crosstalk mechanisms modulate
matrix metalloproteinase expression
C
ell plasticity and invasion provide the basis of tissue morphogenesis and play a fundamental
role in cancer metastasis and tissue fibrosis. Basement membranes are specialised, dense,
sheet-like matrices, that are deposited by every epithelial and endothelial tissue and key to
organ integrity and compartmentalization. Basement membranes provide a barrier to the potential
pathogenic migration of cells. However, in development, and at certain times in disease, cells can
traverse the basement membrane. The mechanisms of how the basement membrane can be both
a crucial barrier as well as a dynamic gate for specific cell in disease remains elusive as of yet. We
have recently reported a previously unidentified laminin fragment that is released from the basement
membrane during mouse and human stem cell differentiation by matrix metalloproteinase 2 (MMP2)
and that modulates MMP2 expression and key pathways involved in the epithelial-to-mesenchymal
transition (EMT) (Horejs et al., PNAS 2014). Specifically, interaction of the laminin fragment with
α3β1-integrin triggers the down-regulation of MMP2 expression, thereby constituting an interesting
cell-basement membrane-cell feedback mechanism. Inhibiting MMPs has been proposed as a
strategy to prevent pathological cell migration and basement membrane breakdown in the course
of EMT. Here, we explore this cell-matrix-cell feedback mechanism to target pathological EMT in
the course of tissue fibrosis. We present an electrospun biomaterial that is functionalised with the
recombinant laminin fragment and that can be directly interfaced with epithelial tissue to interfere
with EMT pathways and inhibit MMP2 expression and activity in vitro and in vivo. We demonstrate
how interaction of the functionalised synthetic membrane with peritoneal tissue inhibits mesothelial
EMT in a mouse model of TGFβ-induced peritoneal fibrosis by decreasing active MMP2 levels, and
propose a mechanism of how the laminin fragment acts downs tream of α3β1-integrin in epithelial
cells, after it is released from the basement membrane.
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Julie Jouette
POSTER P31
Julie Jouette, Antoine Guichet, Sandra Claret
Jacques Monod Institute, CNRS, UMR 7592, Paris Diderot University, Paris, France
Post-translational regulations of the PIP5K Skittles
and its role in cell polarity
T
he control of apical-basal polarity in epithelial layers is a fundamental event in many processes.
A key feature of polarized cells is their ability to maintain an asymmetric distribution of specific
molecular complexes, including the phosphoinositide PI(4,5)P2. Using the Drosophila ovary
as model system, we have recently showed that in the follicular epithelium, PI(4,5)P2 is essentially
regulated by the PIP5K Skittles (SKTL) and is crucial to maintain apical-basal polarity. We have
found that SKTL, by controlling PI(4,5)P2 polarity, regulates the apical targeting of PAR-3 to the
plasma membrane and thus the size of the apical domain (Claret et al., 2014). We had also shown
that in the oocyte SKTL regulates PAR polarity proteins and the maintenance of specific cortical
domains along the antero-posterior axis (Gervais et al., 2008).
Surprisingly, in epithelial cells, only a
mild fraction of SKTL exhibits a polarized distribution similar to its product, PI(4,5)P2. In accordance
with this, when overexpressed, SKTL frequently fails to reach the apical side. This suggests that a
robust process tightly controls the apical accumulation of SKTL. To investigate this process, we
are exploring SKTL regulation through post-translational modifications and addressing if those
modifications are important for cell polarity associated SKTL function. We found that SKTL presents
multiple modifications of which several sites of phosphorylation and palmitoylation. Furthermore, by
combining mass spectrometry and co-immunoprecipitation approaches we identified several kinases
and one phosphatase that are potentially involved in SKTL post-translational modifications. PI(4,5)P2
is involved in regulation of a number of cellular activities including vesicular trafficking, cytoskeleton
organisation and cell motility. This work could also enlighten about the spatiotemporal regulation of
this phosphoinositide by the PI4P5 kinases.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 139
Karolina Uwantege Kabayiza
POSTER P33
Karolina U. Kabayiza, Gauhar Masgutova, Audrey Harris,
Vincent Rucchin and Frédéric Clotman
Université catholique de Louvain, Institute of Neuroscience,
Laboratory of Neural Differentiation, Brussels, Belgium
The Onecut transcription factors regulate differentiation
and distribution of dorsal interneurons during spinal cord development
D
uring embryonic development, the dorsal spinal cord generates numerous interneuron
populations eventually involved in motor circuits or in sensory networks that integrate and
transmit sensory inputs from the periphery. The molecular mechanisms that regulate the
specification of these multiple dorsal neuronal populations have been extensively characterized. In
contrast, the factors that contribute to their diversification into smaller specialized subsets and those
that control the specific distribution of each population in the developing spinal cord remain unknown.
Here, we demonstrate that the Onecut transcription factors, namely HNF-6 (or OC-1), OC-2 and OC3, regulate the diversification and the distribution of spinal dorsal interneurons. Onecut proteins are
dynamically and differentially distributed in dorsal interneurons during differentiation and migration.
Analyzes of mutant embryos devoid of Onecut factors in the developing spinal cord evidenced a
requirement in Onecut proteins for proper production of a specific subset of dI5 interneurons. In
addition, the distribution of dI3, dI5 and dI6 interneuron populations was altered. Hence, Onecut
transcription factors control genetic programs that contribute to the regulation of spinal dorsal
interneuron diversification and distribution during embryonic development
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Anaïs Khuong
POSTER P35
Anaïs Khuong, Harriet Taylor, Zhonglin Wu, Qiling Xu, Rosalind Morley, Lauren Gregory,
Alexei Poliakov, Willie Taylor, David Wilkinson
Neural Development Laboratory & Computational Cell and Molecular Biology Laboratory,
The Francis Crick Institute, London, UK
Cell segregation and border sharpening by Eph receptor - ephrin
mediated heterotypic repulsion
E
mbryonic development involves the formation of precisely organised tissues, by subdivision
of distinct cell populations into different regions demarcated by sharp borders. These borders
are stabilised by cell segregation mechanisms that inhibit intermingling between the adjacent
cell populations. Three main cellular mechanisms may be involved in cell sorting and boundary
maintenance: cell adhesion, cortical tension and cell repulsion. Eph receptors and their ephrins ligands
are a major actor in boundary formation during tissue morphogenesis, by mediating cell signaling
that can regulate adhesion, tension and repulsion. We set out to understand the role of adhesion and
repulsion in cell segregation and boundary sharpening regulated by Eph-ephrin signalling, combining
experiments in cell culture assays and numerical simulations of an individual-based model of cell
behaviour. We carried out high density culture assays of cell segregation and border sharpening, and
quantitated the resulting collective pattern. Cells expressing EphB2 or kinase-inactive EphB2 segregate
and form a sharp border with cells expressing ephrinB1. Knockdown of N-cadherin does not block
segregation, but decreases the size and interconnection of clusters, and strongly disrupts boundary
sharpening. We then experimentally analysed and quantified the repulsion and adhesion behaviour
of individual cells. We found that cells have strong heterotypic and less strong homotypic repulsion,
leading to a short versus long duration of cell-cell contact, respectively. Using the individual-based
model in which all behavioural parameters were experimentally fitted, we showed that differential
repulsion can in principle lead to cell segregation and border sharpening. We finally analysed how
knockdown of N-cadherin modifies the individual behaviour and show that border sharpening is
disrupted due to the increase in homotypic repulsion, which decreases differential repulsion and
the duration of homotypic cell contact. Cell segregation and border sharpening therefore require the
correct balance between heterotypic and homotypic repulsion, which is regulated by N-cadherin and
Eph-ephrin signaling
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 141
Gabriel Krasovec
POSTER P37
Gabriel Krasovec, Jean-Philippe Chambon, Eric Quéinnec
UMR7138 Evolution Paris Seine, France
Morphogenetic role of apoptosis during metamorphic process
A
A
nimal metamorphosis refers to the profound morphological changes that affect an organism.
This developmental transition is characterized by various cellular mechanisms, such as
migration, proliferation, differentiation and programmed cell death (PCD).
poptosis (PCD type I) has long been described in metamorphosis as merely required for
the removal of obsolete structures. However, studies in hydra, drosophila and chicken
gave evidences of caspase-dependent signals released by apoptotic cells that induce cell
proliferation, migration and survival. This study focus on two phylogenetically distant models to
explore the morphogenetic role of apoptosis during metamorphosis.
T
he Ciona intestinalis tadpole-swimming larva (urochordates) begins metamorphosis after
substrate fixation. Apoptosis starts during the onset of the metamorphosis at the posterior
extremity of the larva, propagates as a polarized postero-anterior wave through the larva and
induce tail regression. All the tail’ tissues are eliminated except (i) the endodermal strand and (ii) the
primordial germ cells (PGCs) PGCs and endoderm migrate at the same time during the apoptotic
polarized wave progression. Our results shown that (i) apoptosis promote this process through a
caspase-dependent signal, and that (ii) modulation of apoptotic wave impacts the PGCs movement.
T
he cnidarian planula swimming larva is generated by jellyfish sexual reproduction. Fixation
and metamorphosis of the planula give rise to the sessile polype that is able to asexually
produce jellyfishes. Among cnidarian (Hydractinia echinata, Clytia hemisphaerica), apoptosis
was observed during metamorphosis. At this stage, interstitial stem cells (i-cells), which give the germ
cells in the polype, are present in the planula endoderm but survive in such apoptotic context. We
are currently define the apoptotic profile during Clytia metamorphosis coupled with i-cells detection.
T
his study from distant phyla organisms additional with the data in literature allows us to have
an evolutionary perspective of the morphogenetic role of apoptosis.
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Lilia Laddada
POSTER P39
Cedric SOLER, Krzysztof JAGLA
GRED, INSERM Clermont Ferrand, France
Early interactions between muscle and tendon precursors
during appendicular myogenesis in Drosophila
P
recise connectivity between muscles and skeleton or exoskeleton is crucial for locomotion
of vertebrates or invertebrates. In Drosophila embryo, specialized ectodermic cells give rise
to attachment sites for connecting larval muscles to the exoskeleton. Early differentiation
of the progenitors of these tendon-like cells is muscle independent an d only later in development
differentiation into mature tendons is muscle-dependent. Tendon-like structures in adult leg of
Drosophila are also required but, unlike larval muscle attachment sites, they are formed by a process
of cellular invagination making a long internal lumen around which the muscle fibres are organised.
We previously showed that a specialized subpopulation of muscle precursors called founder cells
(FC) are specified early near tendon precursors and their spatial positioning all along leg development
shows coordinated development of these two tissues. Moreover by altering tendon formation during
the early steps of leg development, we could affect the spatial localisation of subsequent FC and
potentially affect their specification/differentiation. These findings provide the first evidence of early
interactions between muscle and tendon-like precursors. We also showed by the GFP Reconstitution
Across Synaptic Partners (GRASP) method that tendon and muscle cell precursors are in direct
contact suggesting a potential communication between these two types of cells as early as third
larval stage. Finally, in the aim to understand how tendon morphogenesis is controlled we analysed
the role of the Notch pathway, known to be involved in cell in vagination in leg disc, and showed that
Notch regulates the expression of the key transcription factor Stripe (EGR-like), a key role transcription
factor involved in tendon development in both vertebrates and Drosophila.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 143
Julien Laussu
POSTER P41
Laussu Julien, Leggio Bruno, Faure Emmanuel, Michelin Gaël, Malandain Gregoire,
Godin Christophe, Lemaire Patrick
CRBM Research of Biology Cellular Center Montpellier, France
NRIA National Research Institute for Computer Science, France
Quantitatively exploring ascidia embryonic morphogenesis
A
scidian embryonic cleavage is a stereotypical pattern that was first described more than a
century ago. Invariability in early cell lineage seems to be shared by all studied species. If
the timing and the orientation of cell division are already established as strong components
of the stasis of embryonic morphologies, the stereotypical cleavage pattern seems irrelevant to a
normal development.
S
T
ince the development is robust and it allows for some flexibility, to highlight the mechanisms
constraining the development, we need a precise description of the global variability during
morphogenesis and to redefine the term “invariant cleavage pattern”.
he ascidian embryo is an ideal system to investigate individual cell properties like cell
shape adaptation and cell/cell contact. In this study, we propose to first paint a picture of
the embryogenesis variation intra and inter species by cellular resolution high-throughput
4D-imaging data (SPIM technology) during early Ascidian development. While the normal acquisition
of an average embryo is used to describe a population, our strategy is to focus our attention on the
variance of cellular properties.
P
A
recise analysis of the structure of variability during embryogenesis will permit us to explore
the robustness of the system, by imposing external or genetic perturbations, and therefore
investigate evolutionary conservation question.
central part of this research program will be the development of a high-throughput
computational framework that analyzes and formalizes 4D data in order to quantify,
compare, and formally represent the average development of an organism. This requires
the development of an extended spatial and temporal alignment of virtual embryos. In addition
to its biological interest, a major output of this project will be the development of robust general
computational methods for analysis, visualization, and representation of massive high-throughput
light-sheet datasets.
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Morgane Locker
POSTER P43
Diana Roman, Anaïs Lainé, Muriel Perron & Morgane Locker
CNRS, University Paris-Sud, Paris-Saclay Institute of Neuroscience, France
Redox homeostasis and retinal stem cell proliferation
R
A
eactive oxygen species (ROS) were long considered as harmful and detrimental molecules,
which when overproduced can affect a wide range of cellular functions and sustain the
pathogenesis of several diseases. However, it is now widely accepted that ROS also play
physiological roles at basal levels as modulators of key cell behaviours.
lthough they recently emerged as crucial regulators of proliferation and determination of
both pluripotent embryonic and adult stem cells, only a few studies addressed so far their
functions in adult neural stem cells. We thus plan to seek for their potential requirement in
the control of neural stem cell activity, using the Xenopus retina as a model system. Specifically we
aim to address how ROS production imbalance affects retinal stem cell (RSC) proliferative behaviour
in physiological conditions. Our preliminary data demonstrated that interfering with NOX-dependent
ROS production leads to decreased EdU incorporation in RSC. Interestingly, progenitor cells do not
seem affected, suggesting distinct sensitivities of these proliferating populations to ROS levels. The
underlying mechanisms are currently being investigated.
S
econd, we wish to explore how retinal stem cells protect themselves from oxidative stress.
Among potential candidates to control redox homeostasis in these cells is the Hippo pathway
effector YAP. We recently showed that this factor is specifically expressed in Xenopus
retinal stem cells and required to ensure their genomic integrity. Besides, multiple lines of evidence
suggest that the Hippo pathway is involved in cellular stress responses. In line with this, preliminary
experiments revealed a significant decrease in catalase expression in the retina following Yap
knockdown. This suggests that YAP is required for maintaining proper levels of this antioxidant
enzyme in physiological conditions. We will now address whether YAP may act as a sensor of ROS
levels and whether it more generally controls the antioxidant program in RSC.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 145
Gauhar Masgutova
POSTER P45
Gauhar Masgutova, Audrey Harris and Frédéric Clotman
Laboratory of Neural Differentiation, Institute of Neuroscience, France
Université catholique de Louvain, Brussels, Belgium
Onecut transcription factors control the development of sensory neurons
in the dorsal root ganglia and of dorsal interneurons in the spinal cord
W
ithout sensory neurons and their main target in the spinal cord, dorsal interneurons, one
could neither sense touch, temperature, body movements and posture nor pain. Sensory
neurons derive from a subset of neural crest cells. They divide into three major classes
characterized by the early expression of tyrosine kinase receptors for neurotrophic factors (Trk). Small
diameter TrkA+ neurons are activated by noxious stimuli, medium diameter TrkB+ and TrkC+ neurons
are mechanoreceptors and large diameter TrkC+ neurons convey proprioceptive information. During
embryonic development, Onecut transcription factors are present in sensory neurons. Phenotypic
analyses of mouse embryos mutant for the Onecut genes suggest that these proteins are involved
in the differentiation of sensory neurons and may control the onset of their Trk expression. Indeed,
there is an increase of TrkB/C+ and TrkC+ neurons and a transient decrease of TrkA+ neurons.
I
n addition, eight dorsal interneuron populations (early dI1 to dI6 and late dILA or B cells) are
generated in the spinal cord, some of which integrate and process sensory stimuli from the
periphery. The three Onecut are dynamically and differentially expressed in dI2 to dI6 populations.
Mutant embryo analyses demonstrate that Onecut factors are required for proper production of
Phox2a+ dI5 interneurons. In addition, the spatial distribution of dI3, dI5 and dI6 interneurons is
altered, suggesting that Onecut proteins regulate spinal neuronal migration. To identify potential
regulators of these processes downstream of Onecut factors, microarray experiments comparing
the transcriptome of control or Onecut mutant embryos were performed and validated by in situ
hybridization and immunofluorescence. In the absence of Onecut proteins, we uncovered Pou2f2
overexpression in the sensory neurons and in the dorsal interneurons. Experiments are on-going to
characterize the roles of Onecut factors in sensory neuron and spinal dorsal interneuron development
and to determine how Pou2f2 is involved in this process.
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Grégoire Michaux
POSTER P47
Ghislain Gillard, Ophélie Nicolle, Sylvain Prigent, Mathieu Pinot, Grégoire Michaux
IGDR, Rennes, France
Coordinated morphogenesis through tension-induced planar polarity
U
nderstanding how tissues from different developmental origins interact to achieve coordinated
morphogenesis at the level of a whole organism has been mostly studied through the prism
of biochemical signalling pathways controlling the activity of transcription factors. However
morphogenesis of epithelial tissues can also be controlled by biomechanical pathways and we have
used the morphogenetic step of C. elegans embryonic elongation to investigate the links between
a mechanotransduction pathway and the coordinated morphogenesis of three tissues: muscles,
dorsoventral epidermis and lateral epidermis.
C
. elegans embryonic elongation starts by cell shape changes in the lateral epidermis under
the control of actomyosin dynamics which lasts until the end of elongation. A second
step then requires muscle contractions and a biomechanical signalling pathway to the
dorsoventral epidermis to contribute to the maturation of tendon-like structures called C. elegans
hemidesmosomes (CeHD). But the link between muscle contractions and cell shape changes in
the lateral epidermis has never been investigated. Here we show that muscles contractions and
dorsoventral CeHDs are required to establish an axial planar polarity in lateral cells by restricting the
apical PAR module to junctions between lateral cells while it is absent from the junctions with the
dorsoventral epidermis. This planar polarised PAR module then controls actin planar organisation in
lateral cells, thus determining the elongation axis of the whole embryo.
W
e concluded that muscle contractions relayed by dorsoventral CeHD are required to control
the planar polarity of the lateral epidermis. This biomechanical trans-tissular pathway
therefore contributes to achieve a coordinated morphogenesis of the C. elegans embryo.
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Frédéric Moret
POSTER P49
Reynaud Florie
University of Lyon, University of Lyon1, Institut NeuroMyoGene CNRS UMR5310 INSERM
U1217, Villeurbanne France; CNRS UMR 7592, Jacques Monod Institute, Paris Diderot
University Sorbonne Paris Cité, Paris, France
Cerebrospinal fluid-derived Semaphorin3B orients neuroepithelial
cell divisions in the apicobasal axis
T
he orientation of cell division is crucial for tissue morphogenesis and cell fate choices. Up to
now, the intrinsic molecular machinery positioning the mitotic spindles and its coupling to
intrinsic cell polarities retained much attention. In contrast, the contribution of extracellular
signals to cell division orientation is poorly known. In the developing spinal cord, the central canal is
a source of major extracellular signals like morphogens. Here, we provide evidence that extracellular
signals released in the cerebrospinal fluid (CSF) orient the division angle of neural progenitors.
Preventing progenitor access to cues present in the CSF by neural tube opening and genetically
engineered canal obstruction, affects the proportion of planar and oblique divisions. We identified
the Semaphorin 3B (Sema3B) released from the floor plate and the nascent choroid plexus, as a
mediator of this extrinsic control of progenitor division. Genetic knockout of Sema3B phenocopies
the loss of progenitor access to CSF. Delivery of exogenous Sema3B to progenitors in living embryos
compensates this deficiency. We show that Sema3B binds to Neuropilins receptors at the apical
surface of mitotic progenitors and exerts its effect through GSK3} activation and subsequent
inhibition of the microtubule stabilizer CRMP2. Thus extrinsic signaling mediated by Semaphorins
directs orientation of progenitor division in neurogenic zones.
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Gerry Nganou
POSTER P51
Nganou Gerry, Tanaka Miyabi, Coumans Bernard, Grisar Thierry, de Nijs Laurence,
Delgado Escueta Antonio V, Lakaye Bernard
1 GIGA-Neurosciences, University of Liege, Belgium ;
2 MheNS, Maastricht University, The Netherland;
3 Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA GLAHS/UCLA, Los Angeles, California, USA;
4 Neurology, David Geffin School of Medicine UCLA, Los Angeles, CA, USA
Importin-8 could cause CAE/JME by delaying early neuroblast migration
C
hildhood Absence Evolving to Juvenile Myoclonic Epilepsy (CAE/JME) is an uncommon
form of genetic generalized epilepsy that appears as absence in childhood and evolves into
generalized tonic–clonic seizures with myoclonic jerks during adolescence. In some family
of patients affected by CAE/JME, mutations have been observed in the gene encoding for importin-8
(IPO8).
I
PO8 could be at the origin of CAE/JME via its role in the transport of these proteins. RT-qPCR has
shown that IPO8 mRNA is expressed at all ages with no big difference in expression level. Using ISH,
a clear expression of mIPO8 mRNA was observed in the sub-ventricular/ventricular zone (SVZ/VZ),
the cortical plate (CP) and the ganglionic eminences (GE) of developing brain at E14. Both SVZ/VZ
and GE are the “neurogenic niches” that generate glutamatergic and GABAergic neurons respectively.
The implication of IPO8 in the generation of “glutamatergic neurons” was investigated by In Utero
Electroporation (IUE). Using shRNA, we observed that after 3 days, “glutamatergic neuroblasts” do
not reach the CP in contrast to the control condition. This effect can be rescued by the co-expression
of a form of IPO8 that is resistant to the shRNA. When overexpressing the pathological forms of
hIPO8, but not a variant, migration of “glutamatergic neuroblasts” was also impaired. However, when
the observation is made later, i.e. at P5, we observed that the neuroblasts finally reach their correct
layer in the cortex, suggesting IPO8 only delayed but not blocked migration. Experiments dedicated
to the effects of IPO8 on “GABAergic neurons” are under way.
C
onclusion: IPO8 is expressed in mouse brain during development. It shows a clear expression
during embryogenesis in the “neurogenic niches”. Moreover, IPO8 modulates neuroblasts
radial migration in the developing brain. So, abnormal brain development due to IPO8
mutations could be at the origin of CAE/JME.
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Sophie Pantallaci
POSTER P53
Marie Sémon1, Laurent Guéguen, Coraline Petit, Carine Rey, Anne Lambert,
Manon Peltier, Sophie Pantalacci
LBMC, Lyon LBBE, Lyon, France
Comparison of developmental genome expression
in rodent molars reveals extensive developmental system drift
I
n evolution, it is widely believed that phenotypic changes root in developmental changes and
phenotype conservation, in developmental conservation. Seeming phenotype conservation may
however hide evolutionary changes in the underlying developmental mechanisms by which a trait
is produced. This cryptic evolution is also called Developmental System Drift, and the extent of this
phenomenon unclear. We used a well- characterized evo-devo model system, rodent molars, to test
the correlation between phenotypic and developmental evolution. Between mouse and hamster, the
morphology of the lower molars has much less diverged than the morphology of the upper molars.
Is development accordingly more conserved? We compared molar crown formation with a standard
approach, and with a tight transcriptome time-series to get a quantitative molecular profiling of
developmental states. Our data identify common trends in the development of all molars. Upper
and lower molars have their specificities since the early steps of morphogenesis, at the levels of the
pattern of cusp formation, cellular composition and biased gene expression. The extent of difference
in lower vs.upper molar development within one species does correlate with the extentof difference in
final morphology. However, the specificity of lower vs. upper molar development is drowned among
the rapid evolution of development, which is highly species-specific in term of expression levels and
temporal profiles. Divergence in developmental systems is almost as high for lower as it is for upper
molar, despite much lesser morphological changes in lower molar crown. Hence, our results point
an extensive drift in this devel- opmental system. Because serial organs are largely sharing gene
networks, it supports previous theoretical work that suggest a causal link between pleiotropy and
DSD.
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Leslie Ratié
POSTER P55
Ratié Leslie, Desmaris Elodie(1), Keruzoré Marc(1), Fernando Garcia-Moreno (2),
Zoltán Molnár (2), Bellefroid Eric (1)
(1) Laboratory of Developmental Genetics, Department of Molecular Biology and ULB
Neuroscience Institute (Université Libre de Bruxelles); (2) of Physiology, Anatomy and
Genetics, University of Oxford, UK
Delayed SP neuron differentiation and mixed cortical populations
in Dmrt5 mutant mice
T
he generation of diverse neuronal subtypes from multipotent progenitors during development
is the prerequisite for assembling functional neural circuits in the cerebral cortex. Transcription
factors (TFs) are at the core of cortical developmental programs. One of the TFs that is
involved in early cortical development is Dmrt5, which is expressed in apical progenitors in a highcaudomedial to low-rostrolateral gradient in mouse cortex. Dmrt5 is required for normal development
of the caudomedial cortex but its mode of action in corticogenesis remains largely unknown. Here
we investigate the role of Dmrt5 in generation of the subplate neurons.
S
E
ubplate (SP) is a largely transient cortical structure at the interface of white and gray matters
and is required for intracortical and extracortical-circuitries establishment. SP neurons
constitute a heterogeneous population of cells, among the earliest generated in the cerebral
cortex.
xpression patterns of various SP neurons populations markers (Nurr1/Ctgf/Pcp4/Pls3) showed
that the subplate is largely disrupted in absence of Dmrt5. However at later embryonic stages,
SP cells are identified in the right place within the neocortex. In the cortex of conditional knock-
out Emx1-Cre mice, in which Cre-mediated recombination begins in dorsal telencephalic progenitors
at E9.5, a similar reduction of SP cells is observed. In contrast, SP formation appears unaffected in the
cortex of Nestin-Cre embryos, in which recombination occurs from E10.5. Altogether, these results
suggest a delay in the SP formation and a precocious role of Dmrt5 during the cortical development.
Birthdating analyses confirmed that SP cells are more produced at E12.5 than E11.5 in the Dmrt5-/brain. Furthermore, cell proliferation seems also affected in Dmrt5-/- suggesting an indirect role of
Dmrt5 in the cell cycle regulation.
O
n an other hand, we observed an heterotopic expression of Ctip2 within the developping
brain. Currently, we studied the hypothesis of abnormal neuronal migration in Dmrt5-/-.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 151
Bechara Saykali
POSTER P57
Bechara Saykali, Navrita Mathiah, Wallis Nahaboo, Isabelle migeotte
Free University of brussels, IRIBHM, Belgium
Cellular and molecular mechanisms of primitive streak morphogenesis
and nascent mesoderm migration during mouse embryonic development
T
he process of gastrulation is an essential step in the formation of the vertebrate body plan,
allowing the correct placement of precursor tissue layers. Following epithelial-mesenchymal
transition, it relies on cellular migration of the nascent mesoderm. Rho GTPases are major
regulators of actin reorganization and dynamics. The lab has established a role for Rac1 in early
embryo development and gastrulation.
W
e have set up ex vivo whole mount and explant embryo culture with prolonged confocal
and 2 photon excitation live imaging using Brachyury (T)-Cre; mT/mG embryos, which
allows the switching of red fluorescence (membrane Tomato, mT) to green, (membrane
GFP, mG) upon T-Cre mediated recombination exclusively in nascent mesoderm. We take advantage
of this system to visualize in real time cellular ingression through the primitive streak followed by
mesoderm migration, in a physiological 3D scenario. We perform similar experiments in Rac1 and
RhoA conditional mutants.
T
o further study key behavior differences between mesoderm populations, we are building
expression profiles of the T expressing mesoderm cells at different stages and different sites
during gastrulation to. For that reason, we are sorting the populations of interest from whole
embryos through flow cytometry, which is followed by mRNA sequencing. We will select genes
according to how they are differentially regulated and according to function, which we will test in
explant and whole mount electroporation assays which we have developed for this case.
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Ralitza Staneva
POSTER P59
Staneva R., Clark A., El Marjou F., Vignjevic D.
Curie Institute, Paris Descartes University, CNRS, INSERM, France
Dynamic analysis of cancer tissues reveals spatial distribution
of migration and no requirement for cell pausing during division
I
nvasion of cancer cells is a critical step in the malignant progression of cancer and can lead to
metastasis formation. Cancer cell invasion is associated with an increased migratory capacity
of cells leading to their dissemination to distant tissues. In order to address the dynamics and
migration features of cancer cells in their native microenvironment, we used a spontaneous cancer
model based on the targeting of two genetic insults in the mouse intestinal epithelium. Expression
of a constitutively activated Notch1 receptor and loss of p53 lead to the development of aggressive
intestinal carcinoma (N/p53 mice, Chanrion et al, 2014). Cancer cells also express nuclear GFP
which allows their tracking. Here, we explored cell migration phenotypes in tumor slices using a
new method for long term 3D ex vivo imaging by two-photon excitation microscopy. Tumor explants
were viable for up to 40h during which we observed different patterns of cell migration. Half of the
cells had confined migration and short tracks. On the other hand, a small proportion of cells (10%)
had directional, ballistic migration, with long tracks and fast speeds. We observed local migration
patterns, therefore we considered the spatial distribution of migration patterns. We found that the
closer cells are, the more correlated their directions of migration were. Thus, in cancer tissues,
collective behaviors of neighboring cells give rise to large-scale tissue dynamics. Interestingly, we
didn’t observe any substantial cell pausing during division, suggesting that dividing cells in cancer
tissues can still be displaced during division. Our work will help understand collective behaviors of
cells and can bring insights to other dynamics systems, such as developing organisms.
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Dong Tian
POSTER P61
Dong Tian, Yongping Chai, Zhiwen Zhu, Guoxin Feng and Guangshuo Ou
School of Life Sciences, Tsinghua University, Beijing 100084, China
Polarized Actin Polymerization Enlarges Daughter Cell Asymmetry
A
symmetric positioning of the mitotic spindle contributes to the generation of two daughter
cells that have distinct sizes and fates. Here, we described an asymmetric division in the
Caenorhabditis elegans Q neuroblast lineage that began with an asymmetrically positioned
spindle and continuously enlarged daughter cell asymmetry, producing the smaller of which underwent
apoptosis in the posterior. During this division, more Arp2/3, WAVE and F-actin accumulated anteriorly,
suggesting that asymmetric expansion forces generated by actin polymerization might enlarge
the asymmetry of daughter cell sizes. Indeed, inhibition of actin polymerization using conditional
knockouts by somatic CRISPR-Cas9 or symmetric polymerization of actin by manipulating the VCA
domain of WAVE on the cortex created a more symmetric division and allowed the survival and
differentiation of the posterior daughter. Thus, the balance of the force by actin polymerization on the
cortex of a dividing cell can govern the size and fate of the daughters.
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Caterina Tomba
POSTER P63
Caterina Tomba, Florian Maechler, Anastasiya Trushko, Ilaria Di Meglio, Aurélien Roux
University of Geneva, Department of Biochemistry, Switzerland
Epithelium mechanics under external curvature constraint
T
he deformation of flat epithelia into a given shape is specific to each organ and its function in
the organism. For example, during the gut formation, an initially smooth gut tube is formed
and then intestinal villification takes origin by muscle constriction (Shyer et al., Science,
2013). Once the villi shape is established, it is maintained throughout of life. Therefore, gut cells have
to function in regions of different curvature. Despite of the growing evidence of the interplay between
external forces, mechanotransduction and organ morphology, little is known about cell adaptation to
external geometrical constraints. For this study, we have developed two complementary techniques
to control epithelium curvature and to investigate its possible role in cell growth and organisation.
These in vitro systems have the advantage to provide simple tools to control the physical cell
environment and to isolate the effects of its properties on cell growth. In particular, our researches
focus on quantitative studies of epithelial monolayer adaptation, e.g. in terms of cell shape and
proliferation.
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Sakina Torch
POSTER P65
AG Radu1, S. Torch1, F. Fauvelle, F. Gillou, P. Crepieux, P. Hainaut1, M. Billaud, C. Thibert1
Institute for Advanced Biosciences UGA-Inserm U1209-CNRS UMR5309, France
LKB1-dependent control of Sertoli cell polarity and metabolism
is essential for spermatogenesis
T
he LKB1 tumor suppressor controls cell polarity and energy metabolism partly via the
activation of the energetic sensor A MP-activated protein kinase (AMPK). Germline mutations
of the human LKB1 are causally associated with the Peutz-Jeghers Syndrome (PJS), an
autosomal dominant disorder characterized by a high risk of developing cancers affecting several
organs including testicular Sertoli cell (SC) tumor. SC are somatic cells of the seminiferous epithelium
that provide the adequate ionic and metabolic environment essential for germ cells maturation. SC
form the blood testis barrier and control peritubular myoid and interstitial Leydig cells proliferation.
It is well documented that SC preferentially metabolize glucose into lactate instead of oxidizing it
through the mitochondrial oxidative phosphorylation.
B
y deleting Lkb1 gene in murine SC (AMH::Cre Lkb1F/F), we demonstrated the crucial role of
Lkb1 in fertility since male mice were sterile and exhibited a macro-orchidy after birth with
increased testicular weight followed by a progressive regression of the testicular volume and
a marked micro-orchidy. Seminiferous tubules were totally disorganized in the absence of Lkb1.
Although SC differentiation was not affected, their cell polarity was impaired and the hematotesticular barrier was absent. We also observed increased proliferation of germ, myoid and Leydig
cells. Exploration of the SC metabolism revealed both an aberrant upregulation of the nutrient-sensing
mTOR pathway and lipids and carbohydrate accumulation within and around seminiferous tubules in
the absence of Lkb1. Furthermore, HRMAS RMN metabolomics analyses of Lkb1-inactivated testes
revealed profound metabolic deregulations such as non-essential amino acids, probably reflecting
their metabolic adaptation to stressful conditions. By using SC cultures, we demonstrated that
glycolysis was not affected in the absence of Lkb1 whereas cell respiration was clearly augmented,
thus leading to an increase of energy production. Altogether, these findings highlight the crucial role
of LKB1 metabolic signaling in SC function and testis development.
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Camille Vachon
POSTER P67
Camille Vachon, Jean-Louis Bessereau
NeuroMyogène Institute, France
Analysis of syndecan function at the C. elegans neuromuscular junction
T
he extracellular matrix (ECM) plays an essential role in the development and function of
organs and tissues. Syndecan is an ECM component that belongs to the heparan sulfate
proteoglycan (HSPG) family. It is composed of 3 polysaccharidic chains linked to a core
transmembrane protein. In C. elegans syndecan is coded by a single gene sdn-1. It is required for
normal vulva development and axonal guidance (Minniti et al., 2004) (Rhiner et al., 2005). Sugar
chains are extensively modified including sulfation, acetylation and epimerisation of individual sugar
residues. Recent reports suggest that some modifications are cell specific (Attreed et al., 2016)
supporting the hypothesis of an HS code.
H
SPG are present at neuromuscular junctions (NMJ) but their synaptic functions remain
uncharacterized. In C. elegans body-wall muscle cell receive excitatory and inhibitory
innervation from cholinergic and GABAergic motoneurons, respectively. Ce-punctin (also
known as MADD-4) is an ECM protein secreted by motoneurons in the synaptic cleft. Specific
combinations of Ce-punctin isoforms trigger the clustering of acetylcholine or GABAA receptors at
synaptic sites.
W
e used a BFP knock-in allele generated by the Bülow lab to detect SDN-1 and we observed
that SDN-1 is present at NMJs and seems to be enriched at cholinergic neuro-muscular
synapses. Using single-chain antibodies to label specific HS modifications in vivo suggests
that some modifications could be prevalent at cholinergic junctions. Preliminary data indicate that
sdn 1 disruption might affect the localization of acetylcholine receptors. Ongoing experiments and
future plans will be presented at the meeting.
Attreed, M., Saied-Santiago, K., Bülow, H.E., 2016. Conservation of anatomically restricted
glycosaminoglycan structures in divergent nematode species. Glycobiology 26, 862–870.
doi:10.1093/glycob/cww037
Minniti, A.N., Labarca, M., Hurtado, C., Brandan, E., 2004. Caenorhabditis elegans syndecan (SDN-1)
is required for normal egg laying and associates with the nervous system and the vulva. J. Cell Sci.
117, 5179–5190. doi:10.1242/jcs.01394
Rhiner, C., Gysi, S., Fröhli, E., Hengartner, M.O., Hajnal, A., 2005. Syndecan regulates cell migration and
axon guidance in C. elegans. Development 132, 4621–4633. doi:10.124
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 157
Aidamalia Vargas-Lowman
POSTER P69
François Bonneton, David Armisen, Emilia Santos and Abderrahman Khila
Institute of Functional Genomics of Lyon, France
Convergent evolution of embryonic pigmentation in the Gerromorpha
U
nderstanding the origin of novel traits is one of the most important objectives in evolutionary
developmental biology. All species of semi-aquatic bugs (Hemiptera, Gerromorpha), exhibit a
dark red pigment in the developing eyes as a result of two pigment synthesis pathways known
as Pteridine and Ommochrome pathways. Some species, however, exhibit red and yellow colouration
in the antennae, the legs and sometimes the abdomen. Based on the known phylogeny of the group,
this extra-ocular pigmentation evolved several times independently and is likely a convergent trait.
We hypothesized that the gene regulatory network responsible for the biosynthesis of eye pigments
has been recruited to produce the extra ocular pigmentation during embryo development. As a first
step to test this hypothesis, we characterized the pigmentation pathway in one species (Limnogonus
franciscanus). In this talk, we present evidence that the entire Pteridine, but not ommochrome,
pigment biosynthesis pathway responsible for red pigment accumulation in the eye has been coopted in extra-ocular tissues in the water strider Limnogonus franciscanus. This co-option resulted
in the accumulation of bright red pigment along the body axis of the embryo. We will discuss both
the evolutionary and developmental implications of this co-option on the biology of water striders.
This work provides significant insights to our understanding of key concepts in evolutionary biology
including from network co-option and convergence.
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Stéphane Vincent
POSTER P71
Antoine Ducuing, Stéphane Vincent
ENS de Lyon, France
DPP and Jun do not drive collective cell migration
during Drosophila dorsal closure
B
one Morphogenetic Protein (BMP) and Jun N-terminal Kinase (JNK) are two prominent
pathways that regulate cell behaviour during development and disease. Both are required for
Drosophila dorsal closure and the impairment of either signal leads to a catastrophic dorsal
open phenotype and the extrusion of internal organs. Thus genetic studies led to the prevalent view
that JNK and the BMP homologue DPP are involved in cell migration. Surprisingly, the dynamic
analysis of dorsal open mutants reveals that both DPP and JNK are dispensable for the dorsalward movement of leading edge cells. In addition, the characterisation of cell behaviour using both
cellular markers and time-lapse analysis indicate that DPP does not prevent cell death in the dorsal
epidermis. Rather, DPP antagonises cell death in the amnioserosa cells that are in the vicinity of the
epidermis. Altogether we provide a novel integrated view of the action of DPP and JNK on cellular
activities and how these contribute to robust, well-tuned morphogenesis.
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 159
Xinyi Yang
POSTER P73
Xinyi Yang, Teresa Ferraro, Julien Pontabry, Nicola Maghelli, Loïc Royer,
Stephan Grill, Gene Myers, Michel Labouesse
Biology Institute Paris-Seine, Paris, France;
Max Planck Institute of Molecular cell Biology and Genetics, France
Pfotenhauerstr. Illkirch, Dresden, Germany
Rotating and elongating embryos: SPIM microscopy reveals
how C. elegans embryos extend through a ratchet mode
R
otating and elongating embryos: SPIM microscopy reveals how C. elegans embryos extend
through a ratchet mode The process of morphogenesis in C. elegans embryos is largely driven
by epidermal cells. Unlike Drosophila and zebrafish, no cell division or cell rearrangement is
involved in C. elegans morphogenesis. Epidermis shape changes, which are characterized by junction
lengthening along the anterior/posterior (A/P) direction, play a key role in this process. The nature
of and the mechanical forces stimulating junction lengthening, as well as the cellular mechanisms
involved are the main objectives of this project. Our lab observed that junction elongation along
A/P direction increases after muscle becomes active, and fails in muscle defective embryos. To
better understand which role muscles play in polarized junction lengthening, we examined the global
and local movement patterns of embryo using Single Plane Illumination Microscopy, focusing on
epidermal adherens junctions and muscle nuclei. We found that wild-type embryos rotated strongly
soon after muscle became active, and equally frequently to an outward or inward direction. However,
muscle defective and Rho-kinase mutant embryos, which stop elongation at the 2-fold stage, scarcely
rotated, suggesting that rotations are important for embryo elongation. By comparing the changes
of cell aspects between each seam cell, we observed that the head, body and tail mechanically
behaved as partially independent entities. We next sought to understand how such movements
could account for the polarized junctions lengthening, keeping in mind that C. elegans embryos
are radially symmetric. By measuring the distance between two dorsal or ventral muscle nuclei,
respectively, we found that dorsal and ventral muscles mostly contract alternatively, accounting for
embryo rotations. Analysis of junction roughness showed that junctions along the A/P direction were
stretched when seam cells were positioned outwards during embryo rotations. Our laser ablation
experiments proved that these junctions were under higher tension when stretched during embryo
rotations. These results depicted that asymmetric muscle activity defines the source of polarity in C.
elegans embryo and provides the local driving force of epidermis stretching. We are currently testing
how it impacts on the insertion of new E-cad molecules during junction remodeling. Xinyi YANGa,
Teresa FERRAROa, Julien PONTABRYb, Nicola MAGHELLIc, Loïc ROYERc, Stephan GRILLc, Gene
Myersc, Michel Labouessea a: Institut Biologie Paris-Seine, 7-9 Quai Saint Bernard, 75005, Paris,
France b: Institut de Genetique et de Biologie Moleculaire et Cellulaire, 1 rue Laurent Fries, 67400
Illkirch, France c: Max Planck Institute of Molecular cell Biology and Genetics, Pfotenhauerstr. 108,
01307 Dresden, Germany
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AUTHORS
INDEX
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164 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Ursula
ABAD
P01
Hervé
ACLOQUE
P02
Julie
AHRINGER
KS
Leiore
AJURIA - ASTOBIZA
OC
Richard
ANDERSON
IS
Guillaume
BALAVOINE
P03
Frédéric
BANTIGNIES
IS
Cyril
BASQUIN
OC
Cécilia
BASSALERT
P04
Renata
BASTO
IS
Yohanns
BELLAÏCHE
KS
Bertrand
BENAZERAF
OC
Florence
BESSE
OC
Flore
BEURTON
P05
Raphaël
BONCHE
P06
Nadège
BONDURAND
P07
Bruno
CADOT
OC
Jordi
CASANOVA
IS
Fabiana
CERQUEIRA CAMPOS
OC
Soline
CHANET
P08
Nicolas
CHARTIER
OC
Sandra
CLARET
P09
Nathalie
COUTURIER
P10
Pénélope
DARNAT
P11
Jean-François
DARRIGRAND
P12
Elena
DE SENA
OC
Stéphanie
DEBRULLE
OC
Jonathan
DEGOSSERIE
P13
Delphine
DELACOUR
OC
Audrey
DESGRANGE
P14
Élodie
DESMARIS
P15
Christina
DONDI
OC
Jeremy
DUFOURT
OC
Mathilde
DUMOND
OC
Jocelyn
ETIENNE
P16
Sandrine
ETIENNE MANNEVILLE
OC
François
FAGOTTO
OC
Julien
FALK
P18
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 165
Mohamad Ali
FAWAL
OC
Emmanuel
GALLAUD
P17
Cécile
GASTON
P20
Yad
GHAVI-HELM
OC
Pascale
GILARDI-HEBENSTREIT
OC
Cécile
GIORDANO
P19
Muriel
GRAMMONT
P22
Marco
GRILLO
OC
Amandine
GUERIN
P21
Marine
GUEYDAN
P24
Alexandre
GUIRAUD
P23
Fisun
HAMARATOGLU
P26
Annaïg
HAMON
P25
Audrey
HARRIS
P28
Luke
HAYDEN
P27
Valeria
HERNANDEZ
P30
Mélina
HEUZÉ
OC
Christine-Maria
HOREJS
P29
Wieland
HUTTNER
IS
Alexandre
JANIN
P32
Julie
JOUETTE
P31
Thomas
JUNGAS
P34
Karolina Uwantege
KABAYIZA
P33
Abderrahman
KHILA
OC
Hanane
KHOURY
P36
Anaïs
KHUONG
P35
Stéphanie
KILENS
P38
Gabriel
KRASOVEC
P37
Nadieh
KUIJPERS
P40
Lilia
LADDADA
P39
Benoît
LADOUX
IS
Laurie-Anne
LAMIRÉ
P42
Julien
LAUSSU
P41
Patrick
LEMAIRE
IS
Pierre-François
LENNE
IS
Jean-Antoine
LEPESANT
P44
Morgane
LOCKER
P43
Christophe
MARCELLE
IS
166 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Paul
MARCOUX
P46
Alfonso
MARTINEZ-ARIAS
IS
Gauhar
MASGUTOVA
P45
Anna
MATTOUT
IS
Tamas
MATUSEK
P48
Grégoire
MICHAUX
P47
Christel
MOOG-LUTZ
P50
Eduardo
MORENO
IS
Frédéric
MORET
P49
Pauline
NAUROY
P52
Gerry
NGANOU
P51
Amanda
OCHOA-ESPINOSA
P54
Francesca
PALLADINO
IS
Sophie
PANTALACCI
P53
Nipam
PATEL
IS
François
PAYRE
IS
Anne
PORA
OC
Olivier
POURQUIÉ
KS
Catherine
RABOUILLE
IS
Anca
RADU
P56
Leslie
RATIÉ
P55
Mélanie
ROUSSAT
P58
Bechara
SAYKALI
P57
Sylvie
SCHNEIDER-MANOURY
IS
Frank
SCHNORRER
OC
David
SHERWOOD
IS
Maleaume
SOULARD
P60
Benoit
SOUQUET
OC
Anne
SPANG
IS
François
SPITZ
IS
Ralitza
STANEVA
P59
Nicolas
TAULET
OC
Chantal
THIBERT
P62
Dong
TIAN
P61
Mathilde
TOCH
P64
Caterina
TOMBA
P63
Patrick
TORBEY
P66
Sakina
TORCH
P65
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 167
Yusuke
TOYAMA
P68
Camille
VACHON
P67
Daan
VAN DEN BRINK
P70
Aidamalia
VARGAS-LOWMAN
P69
Lucie
VAUFREY
P72
Stéphane
VINCENT
P71
Ann
WEHMAN
OC
Alexis
WEINREB
P74
Xinyi
YANG
P73
Zhiwen
ZHU
P76
168 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 169
170 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
LIST OF
PARTICIPANTS
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 171
172 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Ursula
ABAD
France
[email protected]
Iman
ABUMOURAD
Egypt
[email protected]
Hervé
ACLOQUE
France
[email protected]
Markus
AFFOLTER
Switzerland
[email protected]
Eric
AGIUS
France
[email protected]
Julie
AHRINGER
United Kingdom
[email protected]
Leiore
AJURIA ASTOBIZA
France
[email protected]
Richard
ANDERSON
USA
[email protected]
Agnès
AUDIBERT
France
[email protected]
Guillaume
BALAVOINE
France
[email protected]
Laure
BALLY-CUIF
France
[email protected]
Frédéric
BANTIGNIES
France
[email protected]
Cyril
BASQUIN
France
[email protected]
Cécilia
BASSALERT
France
[email protected]
Renata
BASTO
France
[email protected]
Yohanns
BELLAICHE
France
[email protected]
Sophie
BEL-VIALAR
France
[email protected]
Bertrand
BENAZERAF
France
[email protected]
Florence
BESSE
France
[email protected]
Jean - Louis
BESSEREAU
France
[email protected]
Flore
BEURTON
France
[email protected]
Raphaël
BONCHE
France
[email protected]
Nadège
BONDURAND
France
[email protected]
Manuel
BREUER
United Kingdom
[email protected]
Bruno
CADOT
France
[email protected]
Paolo
CALDARELLI
France
[email protected]
Jordi
CASANOVA
Spain
[email protected]
Fabiana
CERQUEIRA CAMPOS
France
[email protected]
Cagri
CEVRIM
France
[email protected]
Soline
CHANET
USA
[email protected]
Nicolas
CHARTIER
Germany
[email protected]
Anaïs
CHAUMERET
France
[email protected]
Claire
CHAZAUD
France
[email protected]
Sandra
CLARET
France
[email protected]
Julien
COURCHET
France
[email protected]
Nathalie
COUTURIER
France
[email protected]
Pénélope
DARNAT
France
[email protected]
Jean - François
DARRIGRAND
France
[email protected]
Alice
DAVY
France
[email protected]
Camille
DE LOMBARES
France
[email protected]
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 173
Pascal
DE SANTA BARBARA
France
[email protected]
Elena
DE SENA
France
[email protected]
Stéphanie
DEBRULLE
Belgium
[email protected]
Jonathan
DEGOSSERIE
Belgium
[email protected]
Delphine
DELACOUR
France
[email protected]
Bénédicte
DELAVAL
France
[email protected]
Audrey
DESGRANGE
France
[email protected]
Élodie
DESMARIS
Belgium
[email protected]
Cristiana
DONDI
France
[email protected]
Sylvie
DUFOUR
France
[email protected]
Jeremy
DUFOURT
France
[email protected]
Mathilde
DUMOND
France
[email protected]
Jennifer
DURANT
France
[email protected]
Jonathan
ENRIQUEZ
France
[email protected]
Jocelyn
ETIENNE
France
[email protected]
Sandrine
ETIENNE-MANNEVILLE
France
[email protected]
François
FAGOTTO
France
[email protected]
Julien
FALK
France
[email protected]
Sandrine
FAURE
France
[email protected]
Mohamad Ali
FAWAL
France
[email protected]
Nadjet
GACEM
France
[email protected]
Vincent
GACHE
France
[email protected]
Emmanuel
GALLAUD
Switzerland
[email protected]
Cécile
GASTON
France
[email protected]
Katrin
GERSTMANN
France
[email protected]
Yad
GHAVI-HELM
Germany
[email protected]
Pascale
GILARDI-HEBENSTREIT
France
[email protected]
Cécile
GIORDANO
France
[email protected]
Victor
GIRARD
France
[email protected]
Yacine
GRABA
France
[email protected]
Muriel
GRAMMONT
France
[email protected]
Marco
GRILLO
France
[email protected]
Amandine
GUERIN
France
[email protected]
Marine
GUEYDAN
France
[email protected]
Antoine
GUICHET
France
[email protected]
Alexandre
GUIRAUD
France
[email protected]
Fisun
HAMARATOGLU
Switzerland
[email protected]
Annaïg
HAMON
France
[email protected]
Audrey
HARRIS
Belgium
[email protected]
Luke
HAYDEN
France
[email protected]
174 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Valéria
HERNANDEZ
France
[email protected]
Mélina
HEUZE
France
[email protected]
Christine-Maria
HOREJS
Sweden
[email protected]
Wieland
HUTTNER
Germany
[email protected]
Christophe
JAGLA
France
[email protected]
Alexandre
JANIN
France
[email protected]
Haixiu
JIN
France
[email protected]
Julie
JOUETTE
France
[email protected]
Thomas
JUNGAS
France
[email protected]
Karolina-Uwantege
KABAYIZA
Belgium
[email protected]
Eirini
KESISOGLOU
France
[email protected]
Abderrahman
KHILA
France
[email protected]
Hanane
KHOURY
France
[email protected]
Anaïs
KHUONG
United Kingdom
[email protected]
Stéphanie
KILENS
France
[email protected]
Anthony
KISCHEL
France
[email protected]
Gabriel
KRASOVEC
France
[email protected]
Nadieh
KUIJPERS
Germany
[email protected]
Lilia
LADDADA
France
[email protected]
Benoît
LADOUX
France
[email protected]
Laurie-Anne
LAMIRE
France
[email protected]
Julien
LAUSSU
France
[email protected]
Serge
LEBECQUE
France
[email protected]
Patrick
LEMAIRE
France
[email protected]
Pierre-François
LENNE
France
[email protected]
Jean-Antoine
LEPESANT
France
[email protected]
He
LI
Germany
[email protected]
Morgane
LOCKER
France
[email protected]
Ingrid
LOHMANN
Germany
[email protected]
Ingrid
LOHMANN
Germany
[email protected]
Nuno
LUIS
France
[email protected]
Christophe
MARCELLE
France
[email protected]
Paul
MARCOUX
France
[email protected]
Alfonso
MARTINEZ-ARIAS
United Kingdom
[email protected]
Gauhar
MASGUTOVA
Belgium
[email protected]
Anna
MATTOUT
Switzerland
[email protected]
Tamas
MATUSEK
France
[email protected]
Cédric
MAURANGE
France
[email protected]
René-Marc
MEGE
France
[email protected]
Grégoire
MICHAUX
France
[email protected]
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 175
Vincent
MIROUSE
France
[email protected]
Christel
MOOG-LUTZ
France
[email protected]
Véronique
MOREL
France
[email protected]
Eduardo
MORENO
Switzerland
[email protected]
Frédéric
MORET
France
[email protected]
Pauline
NAUROY
France
[email protected]
Gerry
NGANOU
Belgium
[email protected]
Amanda
OCHOA-ESPINOSA
Switzerland
[email protected]
Francesca
PALLADINO
France
[email protected]
Sophie
PANTALACCI
France
[email protected]
Nipam
PATEL
USA
[email protected]
François
PAYRE
France
[email protected]
Patrick
PERRIN
Switzerland
[email protected]
Muriel
PERRON
France
[email protected]
Anne
PORA
Germany
[email protected]
Olivier
POURQUIE
USA
[email protected]
Anne-Marie
PRET
France
[email protected]
Catherine
RABOUILLE
The Netherlands
pas de mail
Anca
RADU
France
[email protected]
Léa
RAMBAUD
France
[email protected]
Cathy
RAMOS
France
[email protected]
Leslie
RATIE
Belgium
[email protected]
Ana
ROGULJA-ORTMANN
Germany
[email protected]
Mélanie
ROUSSAT
France
[email protected]
Charline
ROY
France
[email protected]
Florence
RUGGIERO
France
[email protected]
Gael
RUNEL
France
[email protected]
Merabet
SAMIR
France
[email protected]
Bechara
SAYKALI
Belgium
[email protected]
Sylvie
SCHNEIDER-MAUNOURY
France
[email protected]
Frank
SCHNORRER
France
[email protected]
David
SHERWOOD
United Kingdom
[email protected]
Chiara
SINIGAGLIA
France
[email protected]
Maleaume
SOULARD
France
[email protected]
Benoit
SOUQUET
France
[email protected]
Anne
SPANG
Switzerland
[email protected]
François
SPITZ
France
[email protected]
Ralitza
STANEVA
France
[email protected]
Michèle
STUDER
France
[email protected]
Nicolas
TAULET
France
[email protected]
176 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
Pascal
THEROND
France
[email protected]
Chantal
THIBERT
France
[email protected]
Dong
TIAN
China
[email protected]
Mathilde
TOCH
Belgium
[email protected]
Caterina
TOMBA
Switzerland
[email protected]
Patrick
TORBEY
France
[email protected]
Sakina
TORCH
France
[email protected]
Yusuke
TOYAMA
Singapore
[email protected]
Camille
VACHON
France
[email protected]
Lorena
VALVERDE ESTRELLA
France
[email protected]
Daan
VAN DEN BRINK
France
[email protected]
Aidamalia
VARGAS LOWMAN
France
[email protected]
Lucie
VAUFREY
France
[email protected]
Stéphane
VINCENT
France
[email protected]
Alain
VINCENT
France
[email protected]
Ann
WEHMAN
Germany
[email protected]
Alexis
WEINREB
France
[email protected]
Xinyi
YANG
France
[email protected]
Xin
ZHOU
France
[email protected]
Zhiwen
ZHU
China
[email protected]
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 177
178 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
USEFUL
INFORMATION
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 179
180 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
CONGRESS PLACE - ESPACE TÊTE D´OR
103, boulevard de la Bataille de Stalingrad
69100 Lyon-Villeurbanne, France
Phone : +33 (0)4 78 94 69 00
TEMPERATURES
CREDIT CARDS
Wednesday 26th April
18°C /9°C – 65°F /48°F
A Few Thunderstorms
In The Afternoon
Credit cards are accepted
in a large number of shops,
hotels and restaurants.
Thursday 27th April
16°C /6°C - 61°F /42°F
Cloudy
CURRENCY
Friday 28th April
14°C /5°C - 57°F /41°F
Cloudy
Saturday 29th April
14°C /5°C - 57°F /41°F
Partly Sunny
Euro
LANGUAGE
French
(many people speak English)
BANKS
TIME ZONE
GMT +1h
(6 hours ahead from New York,
9 hours behind Sydney,
7 hours from Tokyo)
From Tuesday to Saturday
09:00 am to 12:30 pm
and 02:00 pm to 06:00 pm
CONTACT
ATouT.Com Agency
+33 6 58 08 32 23
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 181
ACCESS
By the road:
Exit n° 4 «Porte de Saint Clair»
Direction Part Dieu and Villeurbanne
by the Bridge Poincaré
By Tramway:
You can get down at the stop «Le Tonkin»
which is 5 minutes walking from l’Espace Tête d’Or
By Subway:
«Charpennes» station is about 10 minutes
walking from l’Espace Tête d’Or,
you can get there by taking either line A or B
By Bus:
Bus number 70 stops at «Parc Tête d’Or Stalingrad»
which is a hundred meters
away from l’Espace Tête d’Or
182 - 2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY
ESPACE TÊTE D’OR
GARE DE LYON-PART-DIEU
2nd Joint SFBD / SBCF MEETING - WHEN DEVELOPMENT MEETS CELL BIOLOGY - 183
Keynote Seminar - Yohanns Bellaiche
07:00-08:00pm
Coffee break
Chemometec Presentation
Invited Seminar - Francesca Palladino
2 selected short talks
Keynote Seminar - Julie Ahringer
Lunch buffet and Poster Session 1 (Even numbers)
In Parallel:
Sessions 1: GENE REGULATION AND 2: CELL POLARITY & TRAFFIC
Invited Seminar - Session 1: François Spitz
- Session 2: Anne Spang
2 selected short talks
Coffee break
Invited Seminar - Session 1: Anna Mattout
10:00-10:30am
10:30-10:45am
11:45-12:45pm
12:45-03:30pm
03:30-06:15pm
03:30-04:00pm
04:30-05:00pm
05:00-05:30pm
Free dinner
Grégoire Michaux
Krzysztof Jagla
René Marc Mège Michèle Studer
Samir Merabet
Antoine Guichet
Organizing Committee:
07:00pm
ATouT.Com Agency
www.atoutcom.com
+33 4 42 54 42 60
CONTACT
- Session 2: Richard Anderson
05:30-06:15pm 3 selected short talks
06:15-06:45pm Invited Seminar - Session 1: Alfonso Martinez Arias
- Session 2: Wieland Huttner
04:00-04:30pm
10:45-11:15am
11:15-11:45am
Plenary Session 1: NUCLEAR ARCHITECTURE, EPIGENETICS
Invited Seminar - Frédéric Bantignies
2 selected short talks
09:00-11:45am
09:00-09:30am
09:30-10:00am
THURSDAY 27th APRIL
Registration
cocktail
04:00-06:00pm
06:00-07:00pm
WEDNESDAY 26th APRIL
Coffee break
Invited Seminar - Session 3: Patrick Lemaire
- Session 4: David Sherwood
2 selected short talks
Invited Seminar: François Payre
SFBD Thesis Price
04:30-05:00pm
05:00-05:30pm
05:30-06:00pm
06:00-06:30pm
06:30-06:50pm
12:30-12:45pm
11:30-12:30pm
11:00-11:30am
Concluding remarks and departure
Keynote Seminar - Olivier Pourquié
2 selected short talks
Invited Seminar - Christophe Marcelle
Coffee break
10:00-10:30am
10:30-11:00am
Plenary Session 3: MORPHOGENESIS & ORGANOGENESIS
Invited Seminar - Renata Basto
Invited Seminar - Jordi Casanova
09:00-11:45am
09:00-09:30am
09:30-10:00am
SATURDAY 29th APRIL
Dinner at «La Brasserie Georges» (Lyon 69002)
2 selected short talks
04:00-04:30pm
07.00pm
Invited Seminar - Session 3: Nipam Patel
- Session 4: Pierre-François Lenne
03:30-04.00pm
2 selected short talks
Invited Seminar - Sylvie Schneider-Maunoury
11:30-12:00am
12:00-12:30am
In Parallel:
Sessions 3: EMERGENT MODELS & EVOLUTION AND 4: CELL MIGRATION & ADHESION
MP Biomedicals Presentation
Invited Seminar - Benoît Ladoux
10:45-11:00am
11:00-11:30am
03:30-06:15pm
Alvéole Presentation
10:30-10:45am
Lunch buffet and Poster Session 2 (Odd numbers) AG SFBD (02:00pm)
Coffee break
10:00-10:30am
12:30-03:30pm
Plenary Session 2: SIGNALLING
Invited Seminar - Eduardo Moreno
Invited Seminar - Catherine Rabouille
09:00-11:45am
09:00-09:30am
09:30-10:00am
FRIDAY 28th APRIL
April 26 - 29, 2017 / Lyon, France
WHEN DEVELOPMENT MEETS CELL BIOLOGY
2nd Joint SFBD / SBCF Meeting