Collaborative Research: The circadian clock's control of seasonal dormancy in mosquitoes

该研究项目的总体目标是了解昼夜节律时钟调节北方家蚊（库蚊）越冬休眠的分子机制，库蚊是一种传播多种疾病的蚊子。蚊子在漫长的夏季白天繁殖活跃，在短暂的冬季白天进入滞育或越冬休眠，此时它们的活动较少，并保存能量以在不利的环境条件下生存。生活在温带环境中的生物能够通过对白昼长度或光周期的变化做出反应来预测和准备冬天的到来。昆虫究竟是如何测量白天长度的尚不清楚，但提供一天中时间信息的生物钟被认为与之有关，因为它控制着植物的季节性反应。了解昆虫是如何将环境信号（如昼长）转化为内部信号（包括基因产物和代谢物）的，将有助于了解其他昆虫的季节反应调节。这项工作有可能产生控制害虫的新方法，通过操纵季节性反应在一年中的错误时间发生，从而改善公众健康。该项目将允许多样化的研究生和本科生充分参与科学研究，并将为初高中学生和教师提供可访问和引人入胜的教育计划和资源。研究人员假设昼夜节律转录因子在昆虫中以时钟和白天长度依赖的方式多向调节生殖和越冬途径。总体研究目的是确定昼夜节律转录因子调控北方库蚊繁殖和越冬滞育相关途径的机制。在无时钟突变背景下，染色质免疫沉淀、深度测序（ChIP-seq）和RNA测序将确定昼夜节律转录因子的靶标，以及它们如何调节与长、短光周期不同季节反应相关的基因。此外，核磁共振波谱将揭示蚊子代谢组的日常和季节性变化，这些变化与繁殖和生存有关。综合起来，结果将显示昆虫如何能够感知昼夜长度的变化，并将这些信息转化为调节不同季节反应的关键分子途径。光周期滞育在昆虫中已经进化了很多次，在昆虫中，它聚集在一些信号通路上，这些信号通路也调节着其他动物的新陈代谢和细胞周期停滞。因此，本研究的结果将超越昆虫滞育研究，在冬眠、衰老和肥胖的研究中具有潜在的应用前景。除了培训下一代科学研究人员外，pi还将领导昆虫学实地营地，并与K-12教师合作，开发和评估使用活体节肢动物，假设驱动的实验室实验以及在线免费提供的有效教育资源的参与程序。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The overall goal of this research project is to understand the molecular mechanisms by which the circadian clock regulates overwintering dormancy in the Northern house mosquito, Culex pipiens, a mosquito species that transmits many diseases. Mosquitoes become reproductively active during long, summer days, and enter diapause or overwintering dormancy during short, winter days, when they are less active and conserve energy to survive unfavorable environmental conditions. Organisms that live in temperate environments are able to predict and prepare for winter’s arrival by responding to changes in daylength, or photoperiod. Precisely how insects are able to measure daylength is unclear, but the circadian clock, which provides information on the time of day, is hypothesized to be involved because it controls seasonal responses in plants. Understanding how insects are able to convert environmental signals, like daylength, into internal cues, including gene products and metabolites, will provide insights into the regulation of seasonal responses in other insects. This work has the potential to generate novel ways to control insect pests by manipulating seasonal responses to occur at the wrong time of year, thereby improving public health. This project will allow diverse graduate and undergraduate students to fully participate in scientific research, and will provide accessible and engaging educational programming and resources for middle- and high-school students and teachers.The investigators hypothesize that circadian transcription factors pleiotropically regulate reproductive and overwintering pathways in both a clock- and daylength-dependent manner in insects. The overall research objective is to determine the mechanism by which circadian transcription factors regulate pathways associated with reproduction and overwintering diapause in the Northern house mosquito, Culex pipiens. Chromatin Immunoprecipitation followed by deep sequencing (ChIP-seq) and RNA sequencing in clock-null mutant backgrounds will identify the targets of circadian transcription factors and how they regulate genes associated with different seasonal responses in both long and short photoperiods. Additionally, NMR spectroscopy will reveal daily and seasonal changes in the metabolome of mosquitoes that are associated with reproduction and survival. Combined, the results will show how insects are able to perceive changes in daylength and translate this information into key molecular pathways that regulate different seasonal responses. Photoperiodic diapause has evolved numerous times among insects, where it converged on a few signaling pathways that also regulate metabolism and cell cycle arrest in other animals. Therefore, the results of this study will extend beyond insect diapause research, with potential applications to the study of hibernation, aging, and obesity. In addition to training the next generation of scientific researchers, the PIs will lead entomology field camps and work with K-12 teachers to develop and assess engaging programming with live arthropods, hypothesis-driven lab experiments, and effective educational resources that will be freely provided online.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.