Download Modelling Argonaute protein interactions as predictors of local

Modelling Argonaute protein interactions as predictors of local
protein translation during synaptic plasticity in neurons
Supervisory team:
Main supervisor: Dr Jonathan Hanley (University of Bristol)
Second supervisor: Dr Lucia Marucci (University of Bristol)
Collaborators: Dominic Alibhai (University of Bristol)
Host institution: University of Bristol
Project description:
MicroRNAs (miRNAs) are small RNAs encoded in the genome that mediate post-transcriptional
silencing of messenger RNA (mRNA) targets by associating with Argonaute proteins in the RNAinduced silencing complex (RISC). Neuronal-specific miRNAs drive neuronal development and have
important roles in various brain disorders, such as Alzheimer’s, Parkinson’s, Autism Spectrum
Disorders and others.
Long-term synaptic plasticity underlies learning
and memory and the tuning of neural circuitry.
The major processes that underlie synaptic
plasticity are the regulated trafficking of AMPA
receptors to change the receptor complement at
the synapse, and alterations in the morphology
of dendritic spines, the structures that house the
postsynaptic machinery. Evidence has recently
emerged that several dendritic miRNAs
modulate the local translation of proteins that
control spine morphology or AMPAR trafficking
and hence synaptic transmission. Argonaute
associates with various proteins that are
essential for, or modulate, translational repression, including GW182, Hsp90, Dicer, MOV10 and
PICK1. Experimental data from our lab indicate that at least some of these interactions are regulated
by the induction of Long-Term Depression (LTD), causing an increase in RISC activity, and hence
providing a mechanism for increasing miRNA-mediated translational repression as a part of the
expression of synaptic plasticity. We hypothesise that these dynamic interactions act in a concerted
network to control the level of miRNA activity required for plasticity.
The aim of this project is to investigate Argonaute protein-protein interactions in neurons in response
to stimuli (eg. NMDA receptor activation) initially using biochemical methods, followed by advanced
imaging techniques (FLIM/FRET) to analyse the temporal and spatial dynamics of protein interactions
in neurons. miRNA activity will be quantified in individual neurons using fluorescent reporters under
the control of 3’ untranslated regions taken from transcripts that are known targets of relevant
miRNAs.
Computational methods will also be employed to describe Argonaute-mediated regulation of gene
expression. The acquired imaging/biochemical data will be combined with previous knowledge about
miRNAs to develop a mathematical model, taking into account other molecular mechanisms that
govern miRNA activity in response to the induction of synaptic plasticity.
This project will be carried out under the expert supervision of Dr. Jonathan Hanley (neuronal cell
biology) and Dr. Lucia Marucci (computational biology). The cell imaging and image analysis will be
carried out in the state-of-the-art Wolfson Bioimaging Facility at the University of Bristol, with the
expert assistance of their technical team.