JH-Met信号调控大猿叶虫卵黄发生关键基因转录的机制研究

The accumulation of yolk is essential for insects early embryonic development. Juvenile hormone (JH) regulates vitellogenesis, but the signal transduction pathway is unclear. The primary reason is that the JH-targeted key genes involved in vitellogenesis have not been identified. Given that, screening the JH-targeted genes and determining the transcription regulatory mechanisms are the most important work. Our previous studies have revealed that JH analog (JHA) methoprene injection significantly promoted vitellogenesis of diapause-destined cabbage beetle Colaphellus bowringi. In regard of that, we plan to screen vitellogenesis-related genes controlled by JH functional receptor Methoprene-tolerant (Met) using Digital Gene Expression Profiling analysis based on the JHA-induced vitellogenesis individuals. RNA interference will be used to verify the function of the key genes on vitellogenesis regulation. Then, The transcriptional activation of vitellogenesis key genes controlled by JH-Met signaling will be analyzed via promoter activation assay. Finally, This study will reveal the mechanism by which JH-Met signaling regulates vitellogenesis of C. bowringi, deepen the mechanism of insect reproduction and JH signaling pathway, and then provide new ideas for pest control.

昆虫卵黄物质积累对早期胚胎发育至关重要。保幼激素(JH)诱导卵黄发生，但具体调控机理并不明确，主要原因在于JH信号途径中参与卵黄发生的关键分子尚未得到鉴定。因此，筛选卵黄发生中JH直接效应基因并解析其转录调控机制，是揭示昆虫卵黄发生分子机制的核心工作。申请人前期研究发现，注射JH类似物(JHA)可以显著诱导大猿叶虫Colaphellus bowringi滞育型个体卵黄发生。本项目拟以JHA诱导的大猿叶虫卵黄发生虫体模型为材料，通过数字基因表达谱分析，筛选JH功能受体Met调控下的直接效应基因。通过启动子激活分析和RNAi实验，揭示JH-Met信号直接效应基因的转录激活机制及其在卵黄发生中的关键作用。研究结果不仅可阐明JH-Met信号调控大猿叶虫卵黄发生的分子机制，而且有助于揭示昆虫生殖机制和JH信号转导通路，还能为害虫防治提供新靶标和新思路。

强大的生殖力是害虫猖獗爆发的重要原因之一，因此开展昆虫生殖发育研究、鉴定生殖发育的关键基因和信号途径，有望发现新的害虫防控靶标，创新害虫防控策略，从而达到害虫控制的目的。本项目以蔬菜害虫大猿叶虫为材料，建立保幼激素JH诱导的卵黄发生模型；利用数字基因表达谱筛选JH功能受体Met调控下的效应基因；通过RNAi实验，揭示JH-Met信号下游效应基因的转录激活机制及其在卵黄发生中的关键作用，旨在探明大猿叶虫卵黄发生和生殖发育的关键基因和信号通路，为害虫控制提供参考。通过项目研究，我们取得如下重要结果和关键数据：1）JH通过Met促进大猿叶虫卵黄发生；2）JH-Met 信号通过调控大量营养代谢基因参与大猿叶虫卵黄发生；3）JH-Met信号在转录水平上促进卵黄原蛋白基因Vg1和Vg2、卵黄原蛋白受体基因VgR和转录因子Kr-h1的表达；4）Kr-h1通过上调VgR和mcm4表达从而促进大猿叶虫卵黄发生；5）JH降解酶基因JHE的转录受到JH-Met信号的反馈调节，进而参与生殖调控。这些研究结果不仅有助于揭示昆虫生殖发育机制和JH信号转导通路，还能为害虫防治提供新靶标和新思路。