Dissecting the mechanisms of translational regulation in Drosophila germ stem cells

Background
STAR (signal transduction and activation of RNA) proteins are KH-domaincontaining, RNA-binding proteins whose activity is regulated in response to signals and regulate RNA processes. One family member is Drosophila HOW, which is expressed in the brain, testes and muscles. Mutants exhibit slow heart rates, heart defects and male sterility. Orthologs have been shown to regulate mRNA translation eg. p53 mRNA in C.elegans. HOW is required for germ stem cell maintanence in Drosophila testes and binds to RNAs that regulate differentiation in testes.
Objectives
1)Identify mRNAs translationally regulated by HOW in testes
2)Characterise molecular mechanism of translational regulation by HOW
3)Understand role of HOW regulated translation events in germ cells

Novelty
Transciptome-wide studies of translation have only been possible in the last few years, with most determining regions of translation and translational efficiencies. Combining ribosome profiling with structural analysis and Drosophila genetics is an innovative strategy, to dissect the molecular mechanisms of translational control by a specific protein.

Timeliness
The advent of ribosome profiling recently allowed global assessments of translational regulation. Improvements to the method, including ours (Aspden eLife 2014) now allow translational regulation by specific proteins to be measured. The dogma has been that the majority of gene expression regulation occurs at transcription but recent work has revealed mRNA translation is also a key point of regulation, eg binding of proteins to mRNAs alters the ability of ribosomes to initiate translation. Structural studies of STAR-proteins are currently at the point (including Edwards group), where mechanistic insight into how binding affects RNA activity can be achieved.

Experimental Approach
-Next Generation Sequencing to study translational control (ribosome profiling)
-Biochemical structural methods to understand how RNA-binding occurs and how this affects the ribosome (X-ray crystallography)
-Drosophila genetic analysis to assess how molecular interactions affect germ stem cell biology and fly fertility.