10.6084/m9.figshare.12149724.v1 Allison N. Beachum Allison N. Beachum Elizabeth Tweedie Ables Elizabeth Tweedie Ables Germ cell division and encapsulation by somatic cells during Drosophila oogenesis require the orphan nuclear receptor ftz-f1 TAGC 2020 2020 oocyte escort cells germline follicle cells steroid hormone nuclear hormone receptor ecdysone Developmental Genetics (incl. Sex Determination) 2020-04-20 22:31:00 Poster https://tagc2020.figshare.com/articles/poster/Germ_cell_division_and_encapsulation_by_somatic_cells_during_Drosophila_oogenesis_require_the_orphan_nuclear_receptor_ftz-f1/12149724 <p>Gamete production in mammals and insects is controlled by cell signaling pathways that facilitate communication between germ cells and somatic cells. Nuclear receptor signaling is a key mediator of many aspects of reproduction, including gametogenesis. For example, the NR5A sub-family of nuclear receptors are essential for gonadogenesis and sex steroid production in mammals. Yet despite the original identification of the NR5A sub-family in the model insect <i>Drosophila melanogaster</i>, it has been unclear whether <i>Drosophila</i> NR5A receptors directly control oocyte production. Here, we demonstrate that <i>ftz-f1</i> (NR5A3) is necessary for multiple aspects of early oocyte development. <i>Ftz-f1</i> is expressed throughout the ovary, including in germline stem cells (GSCs), germline cysts, and several populations of somatic cells. <i>Ftz-f1</i> is necessary in GSCs and their dividing daughters for timely mitotic cyst divisions and accumulation of oocyte-specific proteins in the presumptive oocyte which dictate oocyte positioning within the cyst. In parallel, <i>ftz-f1</i> in somatic escort cells and pre-follicle cells promotes proper cyst division and cyst encapsulation. Interestingly, our data suggest that <i>ftz-f1</i> promotes escort cell-dependent cyst encapsulation via a complex genetic interaction with the steroid hormone ecdysone. We propose the model that Ftz-f1 and ecdysone signaling via the Ecdysone Receptor (NR1H1) interdependently promote communication between escort cells and germ cells. Taken together, these results demonstrate that the reproductive functions of the NR5A sub-family are largely conserved between insects and mammals. Our data underscore the importance of nuclear receptors in the control of reproduction and highlight the utility of <i>Drosophila</i> oogenesis as a key model for unraveling the complexity of nuclear receptor signaling in gametogenesis. </p> <p> </p> <p><b> </b></p>