Abstract

Of 25000 genes encoded from genome, more than 90% are subject to alternative splicing or other post-transcriptional modifications. All these events produce a high number of different proteins that form the basis for the high variety of cells. The RNAbinding proteins (RBPs) play crucial roles in this variability by regulating many steps of biological processes regarding RNA metabolism. The heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to big family of RBPs involved in many aspects of RNA metabolism including RNA stability, intracellular transport and translation. More recently, RALY, a RNA-binding protein associated with the lethal yellow mutation in mouse, has been identified as new member of the hnRNP family even if, its biological function remains still elusive. My PhD project aimed to characterize human RALY and to assess its function in mammalian cells. Initially I dentified the expression pattern of this protein into the cell and I characterized the functional nuclear localization sequence that localizes RALY protein into the nuclear compartment. In order to better understand the role of RALY in the cells, I identified the proteins component of RALY-containing complexes using a new assay named iBioPQ (in vivo-Biotinylation-Pulldown-Quant assay). I also performed polyribosome profiling assay to check the resence of RALY in translating mRNAs. Moreover, a microarray assay was performed in order to identify potential mRNAs whose metabolism appears dependent on RALY expression. Taken together, the results that I obtained suggest that RALY is involved in mRNA metabolism. Unfortunately more studies remain to do before shedding some light on the biological role of RALY in mammals