468V Poster Online - Virtual Posters
Wednesday April 06, 4:00 PM - 7:00 PM

Authors:
Rebecca Oramas ¹; Elizabeth Knapp ¹; Jianjun Sun ^{1, 2}

Affiliations:
1) Department of Physiology & Neurobiology, University of Connecticut; 2) Institute for Systems Genomics, University of Connecticut

Keywords:
m. somatic cell differentiation; a. core promoters and general transcription factors

Across species, ovulation is a process induced by a myriad of signaling cascades that ultimately results in activation of proteolytic enzymes and degradation of follicle cells to release encapsulated oocytes. In order for follicles to ovulate successfully, follicles need to become mature and gain ovulatory competency. Our previous work showed that upregulation of Zinc finger transcription factor Hindsight (Hnt) in follicle cells of stage-14 Drosophila egg chambers induces the expression of octopamine receptor in mushroom body (OAMB) in all follicle cells and matrix metalloproteinase 2 (MMP2) in posterior follicle cells, both of which are essential for ovulation. We also found that NR5A-family nuclear receptor Ftz-f1 is upregulated in stage-10 follicle cells and promotes follicle maturation via bHLH/PAS-family transcription factor Single-minded (Sim). It is largely unclear how Sim, a critical player in central nervous system development, promote follicle maturation and ovulation. In this work, we discovered that Tango (Tgo), a class-II bHLH/PAS-family transcription factor and cofactor of Sim, is also expressed in follicle cells during late oogenesis. In addition, Tgo relocates to the nucleus when Sim is co-expressed in follicle cells from stage 10-12 and stage 14. Genetic manipulation suggests that Tgo is essential for follicle cell differentiation as Sim. Furthermore, we discovered that reupregulation of Sim in stage-14 follicle cells is also essential for ovulation in addition to its role in stage 10-12 follicle cells with Tgo. This late Sim not only induces expression of Hnt, OAMB, and MMP2, but also NADPH oxidase (Nox), another factor involved in superoxide production and ovulation. Together, our work indicates that Sim and Tgo play multiple roles in late stage follicle cells to promote follicle maturation and ovulation.