核受体FTZ-F1介导保幼激素信号调控棉铃虫卵黄发生的机制研究

卵黄发生是昆虫生殖的核心环节。项目前期发现干扰棉铃虫保幼激素(JH)受体Met显著阻遏卵黄原蛋白Vg的合成与吸收，抑制卵子成熟，证实了JH信号通路对棉铃虫卵黄发生起关键调控作用。已有研究表明FTZ-F1是JH调控卵黄发生的激活基因，在棉铃虫中核受体FTZ-F1在卵巢高表达，其表达量与卵母细胞的成熟密切相关，但FTZ-F1如何介导JH调控卵黄发生尚不明确。基于此问题，项目首先明确FTZ-F1在卵黄发生期的表达动态；免疫组织化学技术研究FTZ-F1在卵母细胞的表达定位；RNAi结合表型观察分析FTZ-F1沉默对Vg合成、卵黄沉积、卵子成熟的影响；启动子活性分析FTZ-F1对Vg的转录调控；RNAi结合免疫共沉淀技术分析FTZ-F1和JH受体的互作关系，从而揭示FTZ-F1响应JH信号调控棉铃虫卵黄发生的机制。研究结果有助于筛选控制棉铃虫生殖的潜在靶标，为持续控制棉铃虫种群暴发与危害提供新思路。

Vitellogenesis is a fundamental step in insect reproduction. On the other hand, methoprene-tolerant (Met) is identified as juvenile hormone (JH) receptor. Our previous study in Helicoverpa armigera has demonstrated that knockdown of Met severely suppressed the transcription of vitellogenin, disrupted the yolk protein uptake in oocytes, and impaired oocyte maturation, suggesting the indispensable roles of JH regulation in vitellogenesis. Numerous studies have documented that FTZ-F1 served as an inducible gene in JH-mediated vitellogenesis. Besides, our previous studies in H. armigera have revealed that FTZ-F1 was predominantly expressed in female ovary and its expression was highly correlated with the oocyte maturation, but how FTZ-F1 achieving its functionality in a JH-dependant manner remains ambiguous. In order to illustrate the comprehensive roles of FTZ-F1 in vitellogenesis, the temporal expression pattern of FTZ-F1 during oocyte maturation is first elucidated. Secondly, the immunocytochemical localization is performed to elucidate the cellular location of FTZ-F1 in oocyte. Next, the RNAi experiment targeted to FTZ-F1 is performed to investigate its participation in vitellogenesis, yolk protein deposition and oocyte maturation. A dual luciferase reporter gene assay system is employed to investigate how FTZ-F1 induce vitellogenin through the regulation of promoter activity. With the help of immunoprecipitation assay combined with RNAi, we try to elucidate how FTZ-F1 interacts with Met. Taken together, our results would provide deep insight into the roles of FTZ-F1 in JH-mediated reproduction, highlight potential targets for suppression of H. armigera populations, and contribute to the development of integrated management strategies.