Cytoplasmic mRNA regulation during cell differentation and proliferation during Drosophila development

点击翻译按钮获取中文摘要

My research program seeks to understand how localized cytoplasmic events mediate cell division or differentiation. Our current focus is determining how cytoplasmic bodies containing specific mRNAs and RNA binding proteins locally regulate translation of mRNAs involved in centrosome duplication and division in Drosophila.***It is now clear that mRNAs are not simply passive transmitters of genetic information from the nucleus to the cytoplasmic translation machinery. My laboratory cloned and characterized the Drosophila gawky (gw) gene, encoding an RNA binding protein that nucleates cytoplasmic mRNA regulatory complexes. Gw has a well-known role during microRNA mediated mRNA regulation by RNA processing (P) bodies. Our focus is a second, P-body independent, role for Gw -localized regulation of mRNA translation in specific cytoplasmic domains. We, and others, discovered localized Gw-containing RNA regulatory bodies (locGw-bodies) that act independently of P-bodies. We also identified several mRNAs bound by Gw in embryos but not degraded by P-bodies. A large fraction of these Gw-bound/non-degraded mRNAs encode proteins involved in centrosome synthesis or duplication. Centrosome duplication is required for progression of the cell cycle and establishing cellular asymmetry. We propose that these specialized centrosome locGw-bodies locally regulate mRNA translation involved in these critical cellular processes. For the next 5 years we will ask the fundamental questions -what nucleates specialized locGw-bodies and how does restricted localization and regulated expression of centrosome specific mRNAs bound by locGw-bodies affect embryo cell division or differentiation?***By co-immunoprecipitation, we found four centrosome proteins that interact with Gw: Belle, Centrosomin, CG30122 and Kinesin like protein 61F. We also identified microtubule star, Centrosomal protein 97kDa, centrosomin and Spindle assembly abnormal-6 as Gw-bound mRNAs. Each of these mRNAs encodes proteins known to be involved in centrosome division or duplication.***Our first objective is to determine how these protein interactors induce formation of perinuclear (centrosome) locGw-bodies and how specific mRNAs are targeted into these specialized locGw-bodies in Drosophila cells. Our second objective is to determine how locGw-bodies regulate locally regulate protein translation by correlating mRNA and protein in fixed cells or cell fractions. We are also developing novel vectors for live-cell imaging of mRNAs to monitor mRNA movement into locGw-bodies and how this relates to local protein translation. This will allow direct correlation of cytoplasmic mRNA localization to the effects on protein translation and subsequent processing. Our studies will provide fundamental insight into the poorly understood roles of P-body independent/Gw-mediated mRNA regulation and how this affects centrosome function.