Juvenile hormone action, and crosstalk between juvenile hormone and 20-hydroxyecd

描述（由申请人提供）：蚊子是昆虫媒介，负责传播许多传染病给全世界数亿人。大多数雌性蚊子需要脊椎动物的血液来产卵。多次吸血使蚊子能够将疾病病原体，包括疟疾寄生虫和登革热病毒，从一个人传播到另一个人。我们的长期目标是阐明调节蚊子产卵的分子机制，并确定可用于蚊子控制的目标分子。蚊子卵的发育受两种主要昆虫激素-幼体激素（JH）和20-羟基蜕皮激素（20E）交替高峰的控制。剥夺新出现的成年雌蚊的JH会阻止卵的成熟。另一方面，在蚊子吸血后不久局部使用JH会干扰蚊子对20E的正常反应并影响产卵。我们最近证明，蚊子耐甲氧苯醚（AaMet）蛋白在新出现的成年雌蚊的幼虫激素信号通路中起关键作用。AaMet蛋白与JH结合，并与AaFISC蛋白形成复合物，AaFISC蛋白是20E受体的辅激活因子。发现AaMet和AaFISC与JH靶基因的启动子相关并激活其表达。此外，我们的初步研究表明AaMet介导了JH对20e诱导的基因表达的抑制作用。综上所述，结果表明AaMet和AaFISC是一种幼年激素受体的组成部分。该项目的目的是阐明AaMet如何在调节蚊子卵成熟的幼年激素信号中发挥作用的分子细节。在Aim 1中，我们将对AaMet中的幼激素结合域进行结构-功能研究，并定义与JH高亲和力结合所需的结构决定因素。在Aim 2中，我们将研究AaMet和AaFISC蛋白如何被募集到JH靶基因中的幼年激素反应元件中。在Aim 3中，我们将验证AaMet参与供血雌蚊幼体激素和20E信号之间的串扰的假设。该研究将有助于进一步了解幼虫激素在蚊子体内的分子作用，并为设计针对蚊子JH信号通路的新型农药提供结构基础。

DESCRIPTION (provided by applicant): Mosquitoes are insect vectors responsible for the transmission of many infectious diseases to hundreds of millions of people worldwide. Females of most mosquito species require blood from vertebrate animals for their egg development. Multiple bloodfeedings enable mosquitoes to transmit disease pathogens, including malaria parasites and dengue virus, from one person to another. Our long term goal of this project is to elucidate the molecular mechanisms that regulate mosquito egg production and identify target molecules that can be utilized for mosquito control. Mosquito egg development is governed by alternating peaks of two major insect hormones - juvenile hormone (JH) and 20-hydroxyecdysone (20E). Deprivation of JH in newly emerged adult female mosquitoes will halt egg maturation. On the other hand, topical application of JH to mosquitoes shortly after blood feeding interferes with the normal responses to 20E and impairs egg production. We have recently demonstrated that the mosquito Methoprene-tolerant (AaMet) protein is a key player in the juvenile hormone signaling pathway in the newly emerged adult female mosquitoes. AaMet protein binds to JH and forms a complex with AaFISC protein, a coactivator of the 20E receptor. AaMet and AaFISC are found to be associated with the promoters of JH target genes and activate their expression. In addition, our preliminary studies imply that AaMet mediates the inhibitory effects of JH on 20E-induced gene expression. Taken together, the results suggest that AaMet and AaFISC are components of a juvenile hormone receptor. The objective of this project is to elucidate the molecular details of how AaMet functions in juvenile hormone signaling that regulates egg maturation in mosquitoes. In Aim 1, we will perform structure-function studies of the juvenile hormone binding domain in AaMet and define the structural determinants required for high affinity binding to JH. In Aim 2, we will investigate how AaMet and AaFISC proteins are recruited to juvenile hormone response elements in the JH target genes. In Aim 3, we will test the hypothesis that AaMet is involved in the crosstalk between juvenile hormone and 20E signals in blood-fed female mosquitoes. The study will significantly advance our understanding of the molecular action of juvenile hormone in mosquitoes, and provide a structural basis for designing new pesticides that specifically target the mosquito JH signaling pathway.