423B Poster - 05. Reproduction and gametogenesis
Friday April 08, 2:00 PM - 4:00 PM

Authors:
Amanda Powell; Elizabeth Ables

Affiliation: East Carolina University

Keywords:
b. oogenesis; b. germline stem cell

Oogenesis is the progression of germ cells through mitotic expansion, differentiation into an oocyte, and successful completion of meiosis. Steroid hormones play critical roles in this process in diverse organisms. In Drosophila, the main steroid hormone, ecdysone, facilitates female fertility in part by promoting germline stem cell self-renewal. Foundational studies demonstrated that ecdysone is synthesized primarily in egg chambers during mid-oogenesis; however, more recent data suggests that somatic escort cells, which support germline stem cell differentiation, may also produce ecdysone. Understanding how ecdysone is transported and received in the ovary would help resolve these disparate results. Recent studies by the Yamanaka lab support the hypothesis that ecdysone needs Oatp74D, a membrane transport protein, to import ecdysone into cells, challenging the popular assumption that steroids passively transport through membranes. Oatp74D is well-characterized in the Drosophila blood brain barrier but may have roles in steroid hormone uptake in other cells. Here, we explore whether Oatp74D is necessary for ecdysone-mediated processes during oogenesis. We use transgenic and immunofluorescence approaches to examine localization of Oatp74D in the ovary. We then test whether Oatp74D knockdown in escort cells effects oogenesis and fecundity. Our preliminary results suggest that Oatp74D is not necessary in escort cells for maintenance of germline stem cells but may promote germ cell differentiation. This data will further our understanding of how ecdysone signaling regulates optimal oocyte production.