Analysis of 3'UTR UTR Sequences Sufficient for Localization of Germ Plasm Components in Drosophila Melanogaster

Abstract

mRNA localization is an effective means by which cells regulate protein synthesis in time and space. Temporal and spatial regulation of protein synthesis is essential for establishing asymmetry and polarity, which is necessary for proper development. Several mRNAs, essential for the development of germ cells, have been observed to localize to polar granules within the germ plasm, a cytologically distinct subdomain of the Drosophila oocyte. Among these mRNAs are germ cell-less, polar granule component and cyclin B whose 3’UTRs have shown sufficiency in localizing to the germ plasm. This study aims to identify localization signals within the 3’UTRs of these mRNAs. I have used phylogenetic computational analyses to identify possible conserved functional primary sequence and secondary structure motifs within these 3’UTR sequences. I have also identified RNA-binding proteins with known binding sites within the conserved primary sequence and secondary structure motifs. In order to corroborate my in silico analysis data, I have worked with Whitby Eagle to test fragments of the 3’UTRs of these mRNAs for localization function. None of the 3’UTR fragments successfully localized EGFP to the polar granules in the germ plasm. We may have been unable to detect localization function of our 3’UTR fragments as a result of low expression levels. Alternatively, fragmentation of the 3’UTRs may have destabilized secondary structures or separated localization signals that mediate localization. My in silico data will, however, provide a good reference for future experiments to pinpoint the localization signals within the 3’UTRs of these germ plasm components.