Molecular mechanism of juvenile hormone action in mosquito reproduction

项目摘要 蚊子是疟疾、登革热等多种传染病传播的罪魁祸首 发烧和寨卡病毒。使用杀虫剂控制病媒是目前预防该病的主要手段。 这些疾病的传播。鉴于杀虫剂耐药性在蚊子种群中迅速传播，它 必须在蚊子控制剂的武器库中添加不同作用模式的新杀虫剂。 保幼激素(JH)信号通路是蚊媒控制的重要靶点。JH是一名 蚊子发育和繁殖的关键调节因子。成年蚊子暴露于吡丙草醚的情况 人工合成的JH模拟物，已经显示出有效地为雌性蚊子绝育的前景。我们这个项目的目标是 阐明JH及其模拟物调节蚊子繁殖力的分子途径。 蚊卵发育主要受JH和20-羟基蜕皮酮(20E)的调控。在上一笔资金中 周期中，我们证明耐甲氧戊二烯(MET)蛋白是JH的胞内受体。两者都有 天然JH和吡丙草醚与埃及伊蚊结合，亲和力高。在结合JH时，MET形式a 与Taiman二聚体，Taiman是一种转录因子，参与JH和20E反应。大都会泰曼 复合体直接调控JH控制基因的表达。除了基因组的作用，我们还 报道了一种由质膜启动的快速JH信号。非基因组作用，它依赖于 在受体酪氨酸激酶(RTK)上，调节Met-Taiman复合体的DNA结合，并调节 泰曼基因的选择性剪接。而膜启动的JH信号在其中起着至关重要的作用 膜上JH受体和特异性RTK在蚊子繁殖中的作用尚未确定 蚊子。我们最近的研究表明，MET的一小部分与血浆有关 蚊子细胞的细胞膜。此外，MET的耗竭消除了JH激活的血管内皮细胞的增加 细胞内钙离子，这是核外JH信号的一部分。因此，我们的结果表明，膜- 相关MET作为膜上的JH受体，介导JH的非基因组作用。 在这项拟议的研究中，我们将检验这一假设，即JH在蚊子中的作用是由两者介导的。 膜结合和核MET蛋白，而吡丙草芬使用这个JH信号通路来抑制 20E调控基因表达。在目标1中，我们将定义膜MET在膜结合中的作用 以及膜启动的JH信号转导途径。在目标2中，我们将研究膜MET是如何介导 JH对蚊子的非基因组作用。在目标3中，我们将阐明吡丙氧芬是如何利用JH信号的 抑制卵黄生成20E反应的途径。这项研究将为我们的理解增加一个新的维度 蚊子繁殖所需的JH信号通路。它还可能揭示JH的新目标 可用于农药开发的信号通路。

Project Summary Mosquitoes are responsible for the transmission of many infectious diseases such as malaria, dengue fever, and Zika virus. Vector control using insecticides is currently the primary means of preventing the transmission of these diseases. In light of the rapid spread of insecticide resistance in mosquito populations, it is imperative to add new insecticides with different modes of action to the arsenal of mosquito control agents. The juvenile hormone (JH) signaling pathway is an attractive target for the control of mosquito vectors. JH is a key regulator of mosquito development and reproduction. Exposure of adult mosquitoes to pyriproxyfen, a synthetic JH mimic, has shown promise to effectively sterilize female mosquitoes. Our goal of this project is to elucidate the molecular pathways utilized by JH and its mimics to modulate mosquito fecundity. Mosquito egg development is mainly governed by JH and 20-hydroxyecdysone (20E). In the last funding cycle, we demonstrated that the Methoprene-tolerant (MET) protein is an intracellular receptor of JH. Both natural JH and pyriproxyfen binds to Aedes aegypti MET with high affinity. Upon binding of JH, MET forms a dimer with Taiman, a transcriptional factor that is involved in both JH and 20E responses. The MET-Taiman complex directly regulates the expression of JH-controlled genes. Besides the genomic action, we also reported a rapid JH signaling that is initiated from the plasma membrane. The non-genomic action, which relies on receptor tyrosine kinases (RTK), modulates the DNA-binding of the MET-Taiman complex and regulates the alternative splicing of the taiman gene. While the membrane-initiated JH signaling plays critically important roles in mosquito reproduction, the membrane JH receptor and the specific RTK have not yet been identified in mosquitoes. Our recent study demonstrates that a small portion of MET is associated with the plasma membrane in mosquito cells. Furthermore, depletion of MET eradicates the JH-activated increase in intracellular Ca2+, which is part of extranuclear JH signaling. Thus, our results suggest that the membrane- associated MET acts as a membrane JH receptor to mediate the non-genomic action of JH. In this proposed study, we will test the hypothesis that the JH action in mosquitoes is mediated by both membrane-bound and nuclear MET proteins, and that pyriproxyfen uses this JH signaling pathway to inhibit 20E-regulated gene expression. In Aim 1, we will define the roles of membrane MET in the membrane binding of JH and the membrane-initiated JH signaling. In Aim 2, we will investigate how membrane MET mediates the nongenomic action of JH in mosquitoes. In Aim 3, we will elucidate how pyriproxyfen utilizes the JH signaling pathway to suppress the vitellogenic 20E response. This study will add a new dimension to our understanding of the JH signaling pathway that is required for mosquito reproduction. It may also reveal new targets in the JH signaling pathway that can be exploited for pesticide development.