The molecular basis of sex differentiation in mosquitoes

蚊子是我们一些最致命的疾病的媒介。广谱杀虫剂通常用于控制蚊子，但随着人们越来越关注这些杀虫剂对我们环境的影响，我们需要找到新的、针对物种的蚊子控制方法。我的研究计划的长期目标是开发新的方法，防止蚊子成长为传播疾病的成虫。由于只有雌性蚊子吸血并传播疾病，我们对干扰雌性蚊子特有的发育过程特别感兴趣，目的是设计不会对非目标物种产生不利影响的新型蚊子干预策略。为了找到女性特有的目标，我们需要更多地了解蚊子的性发育。像许多昆虫一样，一系列基因在蚊子胚胎发育的早期就建立了性别。随后出现性别分化，最终产生能够找到寄主、吸血和找到理想产卵地点的雌性。相比之下，雄性则必须寻找配偶，只以花蜜为食，并表现出复杂的求偶行为。控制许多性别二态特征的基因还没有很好的定义，除了一个主开关基因，双性(Dsx)。在传播登革热和寨卡病毒的伊蚊属蚊子中，dsx被认为是一种转录因子，根据是否存在雄性(dsx-M)或雌性(dsx-F)亚型来调节雄性或雌性基因的表达。目前还不清楚哪些基因受dsx的调控。我们在这个资金周期的短期目标是：1)确定哪些基因是dsx-M或dsx-F的靶标；2)探索这两种异构体如何在不同性别中发挥不同的作用；3)研究扰乱它们的功能如何影响性发育。HQP将接受广泛的当前分子技术的培训，包括识别dsx靶标的转录技术，检查dsx水平变化如何影响性发育的基因编辑，以及确定哪些蛋白质与dsx的每个亚型相互作用的质谱学技术，以揭示性别特异性基因表达是如何调控的。使用最新的RNA测序技术，他们将检查性别特定的RNA加工和基因表达发生的时间，以推断蚊子生命中性别分化的开始时间。最后，利用RNA干扰技术，他们将确定哪些基因可以作为靶点，以防止雌性幼虫发育成吸血成虫。埃及伊蚊是亚热带和热带地区的疾病媒介，而白纹伊蚊是北美的一种入侵物种，已到达加拿大边境。这项拟议的研究不仅将揭示这些蚊子耐人寻味的发展方面，还将为开发更安全、更环保的蚊子控制技术提供丰富的新分子靶点。

Mosquitoes are vectors of some of our most deadly diseases. Broad-spectrum pesticides are routinely used to control mosquitoes, but with growing concerns about the impacts of these pesticides on our environment, we need to find new, species-specific methods of mosquito control. The long term goal of my research program is to develop new methods that prevent mosquitoes developing into disease-vectoring adults. As only female mosquitoes blood-feed and therefore transmit disease, we are particularly interested in disrupting female-specific developmental processes, with the goal of designing novel mosquito intervention strategies that have no adverse effects on non-target species. To find female-specific targets, we need to know considerably more about the sexual development of mosquitoes. Like many insects, a cascade of genes establishes the sex early in embryonic mosquito development. Sex differentiation then follows, ultimately producing females that can find hosts, blood-feed, and find ideal egg-laying sites. Males, in contrast, must find mates, feed only on nectar, and display complex courtship behaviours. The genes controlling the many sexually-dimorphic traits have not been well defined, with the exception of one master-switch gene, doublesex (dsx). In mosquitoes of the genus Aedes, which vector dengue and Zika viruses, DSX is thought to act as a transcription factor, regulating the expression of male or female genes, depending on whether the male (DSX-M) or the female (DSX-F) isoforms are present. Which genes are regulated by DSX is still largely unknown. Our short-term goals for this funding cycle are to 1) identify which genes are targeted by either DSX-M or DSX-F, 2) explore how the two isoforms perform different roles in each sex, and 3) examine how disrupting their functions affects sexual development. HQPs will be trained in a broad range of current molecular technologies, including transcriptomic techniques to identify DSX targets, gene-editing to examine how changes in DSX levels affect sexual development, and mass-spectrometry techniques to identify which proteins interact with each isoform of DSX, to uncover how sex-specific gene expression is regulated. Using the latest RNA sequencing technologies, they will examine when sex-specific RNA processing and gene expression occurs, to deduce when sexual differentiation begins in the mosquito's life. Finally, using RNA interference technologies, they will determine which genes can be targeted to prevent female larvae from developing into blood-feeding adults. Aedes aegypti is a disease vector of semitropical and tropical regions, while A. albopictus is an invasive species in North America that has reached Canada's borders. This proposed research will not only uncover aspects of the intriguing development of these mosquitoes, but will also provide a rich source of new molecular targets for the development of safer, more environmentally-friendly mosquito control technologies.