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

描述(申请人提供)：蚊子是昆虫媒介，负责将许多传染病传播给全世界数亿人。大多数蚊子种类的雌性蚊子需要脊椎动物的血液来发育它们的卵。多次采血使蚊子能够将包括疟疾寄生虫和登革热病毒在内的疾病病原体从一个人传播给另一个人。我们这个项目的长期目标是阐明调节蚊卵产生的分子机制，并确定可用于控制蚊子的靶分子。蚊卵的发育受两种主要昆虫激素--保幼激素(JH)和20-羟基蜕皮酮(20E)的交替峰值控制。剥夺新出现的成年雌性蚊子的JH会阻止卵子成熟。另一方面，在蚊子采血后不久局部应用JH会干扰对20E的正常反应，并损害产卵。我们最近已经证明，蚊子耐甲基丁二烯(AAMET)蛋白在新出现的成年雌性蚊子的保幼激素信号通路中起着关键作用。AAMET蛋白与JH结合，并与20E受体的共激活因子AaFISC蛋白形成复合体。AAMET和AaFISC被发现与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，这些结果表明AAMET和AaFISC是保幼激素受体的组成部分。这个项目的目的是阐明AAMET如何在调节蚊子卵成熟的保幼激素信号中发挥作用的分子细节。在目标1中，我们将对AAMET中保幼激素结合域的结构和功能进行研究，并确定与JH高亲和力结合所需的结构决定因素。在目标2中，我们将研究AAMET和AaFISC蛋白如何被招募到JH靶基因中的保幼激素反应元件。在目标3中，我们将验证AAMET参与吸血雌性蚊子中保幼激素和20E信号之间的串扰的假设。这项研究将极大地促进我们对蚊子保幼激素分子作用的理解，并为设计针对蚊子JH信号通路的新杀虫剂提供结构基础。 公共卫生相关性：这项研究的目的是阐明蚊子保幼激素调节成年雌性蚊子卵成熟的分子机制。在分子水平上更好地了解激素的作用对于设计新的蚊子杀虫剂至关重要，这种杀虫剂专门阻断保幼激素的作用，潜在地扰乱蚊子体内受保幼激素调控的所有生物过程。

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. PUBLIC HEALTH RELEVANCE: The goal of this study is to elucidate the molecular mechanism by which the mosquito juvenile hormone regulates egg maturation in adult female mosquitoes. A better understanding of the hormone action at the molecular level is of paramount importance for designing new mosquito pesticides that specifically block the action of juvenile hormone, potentially disrupting all the biological processes in mosquitoes that are regulated by juvenile hormone.