The molecular basis of sex differentiation in mosquitoes

蚊子性别分化的分子基础

• 批准号: RGPIN-2020-05339
• 负责人: Whyard, Steven
• 金额: $ 2.33万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740518
• 关键词: molecular; basis; sex; differentiation; mosquitoes

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.

蚊子是一些最致命疾病的传播媒介。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环境的影响，我们需要找到新的、针对特定物种的蚊子控制方法。我的研究项目的长期目标是开发新的方法，防止蚊子发展成疾病载体。由于只有雌性蚊子吸血并因此传播疾病，我们对破坏雌性特定的发育过程特别感兴趣，目的是设计新的蚊子干预策略，对非目标物种没有不利影响。为了找到雌性特定的目标，我们需要对蚊子的性发育有更多的了解。像许多昆虫一样，在蚊子胚胎发育的早期，一系列基因决定了它的性别。接着是性别分化，最终产生能够找到寄主、吸血和理想产卵地点的雌性。相比之下，雄性必须找到配偶，只以花蜜为食，并表现出复杂的求偶行为。除了一个主开关基因双性（dsx）外，控制许多两性二型性状的基因还没有得到很好的定义。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。哪些基因是由DSX调控的，这在很大程度上仍然是未知的。我们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的目标，2)探索这两种亚型在两性中如何发挥不同的作用，以及3)研究破坏它们的功能如何影响性发育。HQPs将接受广泛的当前分子技术的培训，包括转录组学技术来识别DSX靶点，基因编辑技术来研究DSX水平的变化如何影响性发育，质谱技术来确定哪些蛋白质与DSX的每种异构体相互作用，以揭示性别特异性基因表达是如何被调节的。利用最新的RNA测序技术，他们将检查性别特异性RNA加工和基因表达发生的时间，从而推断蚊子生命中性别分化开始的时间。最后，利用RNA干扰技术，他们将确定哪些基因可以阻止雌性幼虫发育成吸血的成虫。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有趣的发展方面，而且将为开发更安全、更环保的蚊子控制技术提供新的分子靶点的丰富来源。