PROJECT SUMMARY/ABSTRACT
Successful gamete production and survival of offspring in humans and invertebrates depends on optimal
nutrition. The molecular mechanisms connecting gamete production with nutritional cues, however, remain
unclear. Steroid hormones, via specific nuclear receptors, are diet-induced signals that promote germ cell
development. Our long-term goal is to characterize how ovarian cells respond to steroid hormone signaling. Our
undergraduate-powered research team uses the genetically tractable Drosophila ovary to monitor germ cell
development in vivo in response to dietary and hormonal cues. The steroid hormone ecdysone has long been
recognized for its role in oocyte development. Previous studies, however, have been unable to disentangle the
multitude of effects of the steroid hormone, precluding identification of relevant molecular mechanisms. In this
proposal, a team of undergraduates and Master’s students will test the hypothesis that ecdysone signaling
directly modulates the cell cycle in germ cell daughters to promote oocyte specification. In Aim 1, we will use
candidate and unbiased approaches to define how ecdysone signaling promotes germ cell mitotic divisions. In
Aim 2, we will use new germline-specific tools to genetically manipulate ecdysone signaling and investigate
whether ecdysone signals promote germ cell mitotic divisions and/or meiotic onset independently of somatic cell
signaling. In Aim 3, we will query the roles of germ cell-enriched ecdysone signaling targets as possible
mechanisms driving oocyte specification. Our study will conclusively demonstrate whether and how ecdysone
signaling promotes germ cell proliferation and oocyte differentiation via multiple, parallel mechanisms.
Furthermore, this proposal will continue to support infrastructure at a large, regional, rural, public university,
using a very approachable model system to provide high-impact biomedical research experiences to first-
generation and minority undergraduates in a supportive training environment.