昆虫蜕皮激素脉冲负调控因子的鉴定及其功能研究

蜕皮激素是昆虫体内最重要的激素之一，其“脉冲”分泌方式对昆虫发育进程的正常进行是必要的。蜕皮激素脉冲的形成受激素合成过程的起始和结束时间协同控制。目前，人们对于蜕皮激素合成的调控机理已有较多认识。但是，昆虫如何抑制蜕皮激素合成从而终止激素脉冲的研究则少有报道。我们前期在家蚕和黑腹果蝇鉴定出两个保守的候选转录因子，并且发现在果蝇中过表达转录因子会抑制蜕皮激素合成酶基因的表达，而突变则会增加这些基因的表达。因此，我们推测这两个候选转录因子可能是昆虫蜕皮激素合成通路的负调控因子。在此基础上，本项目将以家蚕和果蝇作为研究模型，通过过表达和敲除/敲低候选转录因子，研究它们对蜕皮激素脉冲的形成以及蜕皮和变态等发育进程的影响；进一步解析候选转录因子影响昆虫蜕皮激素合成酶基因表达的调控机制；最后揭示蜕皮激素脉冲的调控因子之间的相互作用方式。项目研究结果将为阐明蜕皮激素脉冲形成的分子调控网络提供新线索。

Ecdysone is one of the most important hormones to regulate the development of insects. The pulsatile secretion of the hormone plays a vital role in controlling the normal development of insects. Generally, the formation of ecdysone pulses is synergistically controlled by the start and end time of the hormone biosynthesis process. At present, people have a relatively good understanding about the regulation mechanism to initiate ecdysone synthesis. However, there are few reports on how insects turn-off ecdysone biosynthesis and then stop the hormone pulse. In our previous analysis, we identified two conserved candidate transcription factors in Bombyx mori and Drosophila melanogaster, and found that overexpression of transcription factors in Drosophila suppresses the expression of ecdysteroidogenic genes (Halloween genes). Conversely, mutations could increase expression of Halloween genes. Therefore, we speculate that these two candidates may be negative regulators of the insect ecdysone biosynthesis pathway. In this project, we will use silkworm and fruit flies as models to study their effects on the formation of ecdysone pulses and development processes such as molting and metamorphosis through overexpression and knockout / knockdown of candidate transcription factors. Next, we will reveal the regulatory mechanism of the candidate transcription factors to affect the expression of Halloween genes in insect. Finally, the molecular interaction among different ecdysone pulsed regulators will be studied. The results of the project will provide new clues for elucidating the molecular regulation network of the ecdysone pulse formation.