Download (RBPs) have been demonstrated to perform central roles in these

2013년 한국분자세포생물학회 식물분자생물학분과 심포지엄 및 제1회
식물후성유전체학 심포지엄
“Epigenomics in Plants 2013”
주관: 한국분자세포생물학회 및 차세대유전체연구사업단
일시 및 장소: 2013년 11월 11일, 서울대학교 25-1동 국제회의실
13:30 ~ 14:00: 등록 및 한국식물후성유전학연구회 회원 접수
14:00 ~ 14:10: 인사의 말씀 (차세대유전체사업단장 박범석, 식물분자생물학분과장 이일하)
I. 한국분자세포생물학회 식물분자생물학분과 주관 세션 (좌장: 노유선)
14:10 ~ 14:35 강훈승 (전남대 교수): RNA-binding proteins, RNA chaperones, and RNA metabolism in plant
development and stress responses
14:35 ~ 15:00 최연희 (서울대 교수): MOS7, an Arabidopsis Nup88 homolog, is crucial for gamete
formation
15:00 ~ 15:25 이병하 (서강대 교수): Splicing-involved RNA biology
15:25 ~ 15:40 석혜연 (부산대 박사과정): EMF1 interacts with EIP1, EIP6 or EIP9 involved in the
regulation of flowering time in Arabidopsis
15:40 ~ 16:00 Coffee Time
II. 차세대유전체연구사업단 주관 세션 (좌장: 신찬석)
16:00 ~ 16:25 최상봉 (명지대 교수): Puf RNA-binding proteins and RNA decay
16:25 ~ 16:50 허진회 (서울대 교수): Nonadditive transcriptional regulation in xBrassicoraphanus derived
from intergeneric hybridization between Brassica rapa and Raphanus sativus
16:50 ~ 17:15 허재복 (동아대 교수): Long non-coding RNA-mediated epigenetic repression of flowering
pathway genes in Arabidopsis
17:15 ~ 17:30 정영민 (가톨릭대 연구교수): Distinctive roles of two JmjC domain-containing proteins in the
repression of FLC in Arabidopsis
17:30 ~ 17:45 Closing Announcement & Photo Time
(※) 본 심포지엄에서는 한국식물후성유전학연구회(회장 노유선, 간사 신찬석)의 창립을 기하여
정회원(박사급) 및 준회원(연구원 및 대학원생) 등록을 진행합니다(회비 없음). 후성유전학에 관심
있는 모든 분들의 적극적 참여를 부탁 드립니다.
RNA-binding Proteins, RNA Chaperones, and RNA Metabolism in Plant
Development and Stress Responses
Hunseung Kang
Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam
National University, Gwangju, 500-757 Korea
Posttranscriptional RNA metabolism is recognized as a key regulatory process in the growth,
development, and stress response of plants, and a variety of RNA-binding proteins (RBPs)
have been demonstrated to perform central roles in these cellular processes. In particular,
certain RBP family members play their roles as RNA chaperones that aid in proper RNA
folding via structural rearrangement during RNA metabolism. During the last years, we have
extensively investigated the functional roles of diverse RBP family members in the process of
plant growth and development as well as the stress response of plants. RBPs unique to minor
spliceosome complex and is involved in the splicing of U-12 type minor introns, glycine-rich
and zinc finger-containing RBPs, cold shock proteins, and RNA helicases have been
extensively studied for their roles in plant growth and stress responses. In addition, functional
analysis of chloroplast-targeted nuclear-encoded RBPs showed that they play crucial roles for
the gene expression, biogenesis, and function of chloroplasts under normal and stress
conditions. All of these results point to the importance of posttranscriptional regulation of
RNA metabolism in plants. In this talk, discussed will be recent progress and novel findings
as well as remaining challenging questions on the functional roles of RBPs and RNA
chaperones in plant growth, development, and stress responses.
MOS7, an Arabidopsis Nup88 Homolog, Is Crucial for Gamete Formation
Geun-Tae Park and Yeonhee Choi
Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
One of the most striking differences between the developmental approaches of plants and
animals is that the several mitotic divisions intervene between meiosis and gamete formation.
Mature plant gametes are produced after a couple of successive mitotic divisions in haploid
cells that exist only in flowering plants and following cytokinesis are critical. However, the
information and mechanisms of genes which mediate these major events during both
gametophyte developments are still largely unknown. Here, we show that MOS7 (Modifier
Of Snc1,7) that is homologous to human and Drosophila Nup88 nucleoporin (NUP) is critical
for male and female gamete formation as well as embryo development. Haplo-insufficient
mos7-5 allele in megaspore mother cell (MMC) and pollen mother cell (PMC) resulted in
delayed phenotypic defects after meiosis, during subsequent mitotic divisions. MOS7 is
expressed in various tissues and cells including MMC and PMC. No homozygous mos7-5
mutant was obtained, indicating an embryo lethality. mos7-5 mutant showed defects in
cortical microtubule in microspore and in CenH3-GFP incorporation during pollen mitosis I
(PMI). Mitotic spindle assembly, spindle attachment to the kinetochore as well as fragmoplast
and cell plate formation were also defected during gametogenesis in mos7-5 mutant. Yeast
two hybrid screen identified dynein and kinectin which are microtubule associated proteins
(MAPs) as MOS7-interacting partners. Taken together, our data suggest that MOS7 plays an
important role in microtubule dynamics possibly together with MAPs during gametogenesis.
Splicing-involved RNA Biology
Byeong-ha Lee
Department of Life Science, Sogang University, Seoul 121-742, Korea
Arabidopsis STABILIZED1 (STA1) encodes a protein that is homologous to human U5
snRNP-associated 102-kDa protein (PRPF6), and the yeast pre-mRNA splicing factors,
PRP1p (fission yeast) and Prp6p (budding yeast), and is important in pre-mRNA splici
ng and mRNA stability. The pleiotropic defects of development, chilling sensitivity an
d hypersensitivity to ABA are observed in sta1-1, a weak allele of sta1. sta1-1, show
ing enhanced luminescence under cold stress, was originally isolated from a mutant p
ool generated with the bioluminescent plant harboring the stress-inducible RD29A prom
oter-driven luciferase gene (RD29A-LUC). Some developmental defects found in sta11 resembled those found in miRNA biogenesis mutants such as hyponastic leaves1-1 (
hyl1-1) and serrate-1 (se-1). Similar to these miRNA biogenesis mutants, sta1-1 accu
mulated significantly lower levels of mature miRNAs and concurrently higher levels o
f pri-miRNAs than wild type. The dramatic reductions of mature miRNAs were associ
ated with the accumulation of their target gene transcripts and the corresponding devel
opmental defects. The reduction of miRNA accumulation in sta1-1 appeared to be bec
ause of the sta1-1 decfects in splicing of intron-containing pri-miRNAs. In addition, st
a1-1 decreased transcript levels of DICER-LIKE1 (DCL1) gene. These results suggest
that STA1 is involved in miRNA biogenesis directly by functioning in pri-miRNA spli
cing and indirectly by modulating the DCL1 transcript level. Our efforts and recent fi
ndings to establish STA1-mediated RNA metabolism will be presented and discussed.
EMF1 Interacts with EIP1, EIP6 or EIP9 Involved in the Regulation of
Flowering Time in Arabidopsis
Hye-Yeon Seok, Hee-Yeon Park, Sun-Young Lee, Sun-Ho Kim, Vaishali N. Tarte, Z. Renee
Sung and Yong-Hwan Moon
Department of Molecular Biology, Pusan National University, Busan 609-735, Korea
Flowering time of higher plants is finely regulated by floral inducers and floral repressors.
EMBRYONIC FLOWER (EMF) 1 gene is necessary for the maintenance of vegetative
development and functions as floral repressor. To investigate the molecular mechanism of
EMF1-mediated plant development, we screened EMF1-interacting proteins and identified
three EMF1-Interacting Proteins (EIPs), EIP1, 6 and 9, predicted to encode a WNK kinase, a
B-box zinc-finger protein and a DnaJ-domain protein, respectively. All of heterodimers
between EMF1 and EIP1, 6 or 9 were localized in the nucleus. The middle and the C-terminal
regions of EMF1 played an important role in the interaction with EIP proteins. The Cterminal region of EIP1, including PWNK motif, and the N-terminal region of EIP6,
including B-box zinc finger, were involved in the interaction with EMF1. In contrast, the
entire ORF of EIP9 was necessary for the interaction with EMF1. Interestingly, although
EMF1 did not directly interact with EMF2, EMF1 interacted with EMF2 via EIP9, forming a
ternary protein complex of EMF1-EIP9-EMF2 and showed granule-like dispersion patterns in
the nucleus. The expression patterns of EIP1, 6 and 9 were similar to that of EMF1 during
vegetative development. In mature plants, the transcripts of EIP1, 6 and 9 were
predominantly expressed in leaves and inflorescence stems while lowly expressed in floral
organs. In addition, eip1, eip6 and eip9 flowered earlier compared to wild type, and the
transcript levels of FT, PI and AG significantly increased while SOC1 and CO transcripts
slightly increased in the mutants. On the contrary, EIP1-, 6- and 9-overexpressing transgenic
plants showed delaying flowering with decreased levels of FT, SOC1, PI and AG. Taken
together, our results suggest that EMF1 interacts with EIP1, 6 and 9 during vegetative
development to regulate flowering time in Arabidopsis.
Puf RNA-Binding Proteins and RNA Decay
Hyung-Sae Kim, Nazia Abbasi and Sang-Bong Choi
Division of Bioscience and Bioinformatics, Myongji University, Yongin, Kyunggi 449-718,
Korea
Post-transcriptional control including mRNA transport, stability, and translation plays a
crucial role in plant growth and development. Most of these processes are inevitably achieved
either directly or indirectly by RNA-binding proteins (RBPs). Although Pumilio proteins
have been characterized in many eukaryotes, their roles in plants are largely unknown. Plants
have more Pumilios than any other organisms, thus Arabidopsis has 25 and rice has 20. One
of the Arabidopsis Pumilios, APUM23, participates in the degradation of poly(A) 18S and
5.8S rRNA by-products in nucleolus. Mutant lacking APUM23 activity showed slow growth
and abnormal growth patterning. The other nucleolar Pumilio, APUM24, is required for
coordinated process of female gametogenesis and embryogenesis. The apum24 mutant
defects in embryo sac development followed by developmental arrest of embryos at various
stages, ranging from zygote to late globular stages. APUM24 plays an important role in
integrating the role of ribosome biogenesis with the proper cell cycle progression. Among
other Pumilios, APUM2 colocalizes with processing-body markers, indicating its role on
RNA homeostasis. APUM2 appears to be involved in the timely mRNA decay of seed storage
protein genes during early germination stage. APUM1 and APUM3 have similar primary
structure with APUM1, suggesting its role on seed germination. [Supported by grants from
Next-Generation BioGreen21 Program, RDA (No. PJ008206)]
Nonadditive Transcriptional Regulation in xBrassicoraphanus Derived
from Intergeneric Hybridization between Brassica rapa and Raphanus
sativus
Jin Hoe Huh
Department of Plant Science, Seoul National University, Seoul 151-921, Korea
Hybrids and polyploids occur in many flowering plants. In particular, hybridization between
different species or genus may produce novel plant species, which is best exemplified in the
Brassica family. However, many interspecific or intergeneric hybrids have reduced viability
and fertility due probably to genome incompatibilities caused by interactions between genes
that are functionally diverged in the respective hybridizing species. xBrassicoraphanus, also
known as Baemoochae, is a newly synthesized intergeneric allotetraploid between Chinese
cabbage (Brassica rapa L.) and radish (Raphanus sativus L.). Unlike most interspecific or
intergeneric allopolyploids, xBrassicoraphanus is a rarely successful polyploid displaying
intermediate phenotypes for many traits. Their stable inheritance and great fertility indicate
that genome incompatibility was overcome after hybridization partly by alleviating a
‘transcriptome shock’ caused by two diverged genomes. Upon hybridization, many of
orthologous genes become homoeologous gene pairs in the same nucleus and they are
expected to be under control of common trans-acting regulators. Also, many transcription
factors and genes involved in signal transduction may reconstitute the signaling networks. In
this study, we obtained the RNA-seq data from xBrassicoraphanus and its respective parents
Brassica rapa and Raphanus sativus using Illumina HiSeq 2000. We performed de novo
transcriptome assembly for xBrassicoraphanus and identified homoeologous genes by
comparing with the two parental transcriptome data. We found that many of homoeologous
genes in xBrassicoraphanus were differentially expressed compared to their hybrid parents.
Interestingly, a significant number of genes were downregulated in a non-additive fashion
deviating from mid-parental value in xBrassicoraphanus. This suggests that global
transcriptional suppression for two parental genomes is one of the mechanisms to stabilize
the gene expression network in the hybrid between the distantly related species.
Long Non-coding RNA-mediated Epigenetic Repression of Flowering
Pathway Genes in Arabidopsis
Jae Bok Heo
Department of Molecular Biotechnology, Dong-A University, Busan, 604-714, Korea
Many eukaryotes, including plants, produce a number of long noncoding RNAs (lncRNAs).
Growing number of lncRNAs are being reported to have regulatory roles in diverse
developmental processes. In Arabidopsis, vernalization results in stable epigenetic repression
of a potent floral repressor, FLOWERING LOCUS C (FLC). Increased enrichment of
Polycomb Repressive Complex 2 (PRC2) and trimethylated Histone H3 Lys 27 (H3K27me3)
at FLC chromatin is necessary for the stable maintenance of FLC repression by vernalization.
A long intronic noncoding RNA (termed as COLDAIR) is required for the vernalizationmediated epigenetic repression of FLC. COLDAIR physically associates with a component of
PRC2 and targets PRC2 to FLC. COLDAIR is required for establishing stable repressive
chromatin at FLC through its interaction with PRC2. In addition, floral integrator genes are
targets of PRC2 complex, resulting in delayed flowering time through repression mechanism
of PRC2 complex. Recently another long non-coding RNA was isolated from floral integrator
gene and characterized the function of this long non coding RNA.
Distinctive Roles of Two JmjC Domain-containing Proteins in the
Repression of FLC in Arabidopsis
Young-Min Jeong1,2,†, Jae-Young Yun2, Jung-Nam Cho1, Richard M. Amasino2
and Yoo-Sun Noh1
1
School of Biological Sciences, Seoul National University, Seoul 151-747, Korea; 2
Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706 USA; †
Current address: Department of Biology, The Catholic University of Korea, Bucheon, 420743, Korea
Histone modifications often impose an epigenetic layer of regulation on eukaryotic gene
expression. Methylation of histone, which is regulated by diverse histone methyltransferases
and demethylases, is one of the important histone modifications. Jumonji C (JmjC) domaincontaining proteins have been reported as histone demethylases, and among the twenty-one
JmjC protein members of Arabidopsis only a few have been functionally characterized. Here
we report that mutations in Arabidopsis thaliana Jumonji 12 (AtJmj12) result in late
flowering caused by increased expression of FLOWERING LOCUS C (FLC), the major floral
repressor in Arabidopsis. The late-flowering of atjmj12 was suppressed by an flc null
mutation and by vernalization, indicating that AtJmj12 affects flowering through FLC and a
member of the autonomous pathway. Chromatin immunoprecipitation assays showed that
AtJmj12:FLAG fusion protein associate directly with FLC chromatin. The double mutants
between atjmj12 and relative of early flowering 6 (ref6), another JmjC domain-containing
FLC repressor, flowered drastically later than either of the single mutants and possessed
increased level of FLC expression. However, mutations in atjmj12 and ref6 caused distinct
patterns within FLC chromatin, indicating that AtJmj12 and REF6 repress FLC expression
through distinct mechanisms.