Investigating a novel role of ejaculate RNA in fertility

PROJECT SUMMARY The male ejaculate of internally fertilizing organisms is a diverse mixture of components including sperm and numerous other macromolecules that are transferred to females during mating. Research on male contributions to fertility has mainly focused on sperm, and, more recently on proteins present in the seminal fluid. While these studies have greatly advanced our understanding of postcopulatory interactions, the relatively high incidence of idiopathic infertility suggests that investigation of understudied molecules in the ejaculate may yield novel insights into novel factors mediating reproductive outcomes. We previously discovered the transfer of RNA from males to females during copulation in Drosophila arizonae. In this proposal, we provide evidence gathered with funding from our recent R21 award demonstrating translation of male RNA transcripts within cells of the D. arizonae female reproductive tract. Building off this work, the goals of the proposed research are to establish functional effects of seminal fluid RNAs on the female postmating response (Aim 1), investigate how they function in females (Aim 2), and identify the source and mechanisms by which they are packaged in males (Aim 3). We capitalize on unique aspects of our D. arizonae/D. mojavensis study system that combine to make a genetically tractable, manipulative experimental system that is particularly well suited to investigate the function of male RNA within the female reproductive tract. With this powerful system we combine proteomic analyses using our recently developed Variant Assisted SILAC Proteomic Analysis (VASPA) approach with detailed investigations of individual mdFTPs (male-derived female translated proteins). Given that RNA appears to be a conserved feature of male ejaculates, we expect our findings will have broad significance for better understanding postcopulatory interactions across a range of species, including humans.