Department of Physiology and Neurobiology, University of Connecticut, Storrs, CN 06269, USA.
Institute for Systems Genomics, University of Connecticut, Storrs, CN 06269, USA.
Development. 2023 Jun 15;150(12). doi: 10.1242/dev.201566. Epub 2023 Jun 14.
Across species, ovulation is a process induced by a myriad of signaling cascades that ultimately leads to the release of encapsulated oocytes from follicles. Follicles first need to mature and gain ovulatory competency before ovulation; however, the signaling pathways regulating follicle maturation are incompletely understood in Drosophila and other species. Our previous work has shown that the bHLH-PAS transcription factor Single-minded (Sim) plays important roles in follicle maturation downstream of the nuclear receptor Ftz-f1 in Drosophila. Here, we demonstrate that Tango (Tgo), another bHLH-PAS protein, acts as a co-factor of Sim to promote follicle cell differentiation from stages 10 to 12. In addition, we discover that re-upregulation of Sim in stage-14 follicle cells is also essential to promote ovulatory competency by upregulating octopamine receptor in mushroom body (OAMB), matrix metalloproteinase 2 (Mmp2) and NADPH oxidase (NOX), either independently of or in conjunction with the zinc-finger protein Hindsight (Hnt). All these factors are crucial for successful ovulation. Together, our work indicates that the transcriptional complex Sim:Tgo plays multiple roles in late-stage follicle cells to promote follicle maturation and ovulation.
在不同物种中，排卵是由一系列信号级联反应诱导的，这些反应最终导致包裹的卵母细胞从卵泡中释放出来。卵泡在排卵前需要先成熟并获得排卵能力；然而，调节卵泡成熟的信号通路在果蝇和其他物种中还不完全清楚。我们之前的工作表明，bHLH-PAS 转录因子 Single-minded（Sim）在果蝇的核受体 Ftz-f1 下游的卵泡成熟中发挥重要作用。在这里，我们证明另一种 bHLH-PAS 蛋白 Tango（Tgo）作为 Sim 的辅助因子，促进卵泡细胞从第 10 期到第 12 期的分化。此外，我们发现阶段 14 的卵泡细胞中 Sim 的重新上调对于通过上调蘑菇体（OAMB）中的章鱼胺受体、基质金属蛋白酶 2（Mmp2）和 NADPH 氧化酶（NOX）来促进排卵能力也是至关重要的，上调作用既可以独立于也可以与锌指蛋白 Hindsight（Hnt）一起发生。所有这些因素对于成功排卵都是至关重要的。总之，我们的工作表明转录复合物 Sim:Tgo 在晚期卵泡细胞中发挥多种作用，以促进卵泡成熟和排卵。
