Mechanism and application of male determination in aedine mosquitoes

 描述（由申请方提供）：埃及伊蚊是登革热、黄热病和基孔肯雅病毒的主要传播媒介。近几十年来，登革热的全球发病率急剧增加，世界上近一半的人口现在处于危险之中。目前还没有针对登革热的具体治疗方法，目前的预防工作完全依赖于有效的病媒控制，而这种控制受到杀虫剂抗药性增加的阻碍。迫切需要通过对蚊子生物学的更好理解来了解新的控制策略。本研究的长期目标是阐明山羊性别决定的机制。我们将继续努力，加强对埃及的了解，并将这些基本知识转化为控制蚊媒传染病的安全和有效方法。只有雌性蚊子以血液为食并传播病原体。因此，雄性是最终的疾病抗性特征。遗传学证据表明，伊蚊的性别决定是由一个显性雄性决定因子（M因子）控制的，该因子位于同型性别决定染色体的M基因座上。尽管M因子在包括蚊子在内的许多昆虫中作为性别决定的主开关而重要，但尚未确定M因子。克服了几个技术瓶颈，我们最近在Ae中发现了一个M因子。埃及人，我们称之为尼克斯。Nix表现出早期胚胎表达，并且是唯一持续与M-位点连锁的基因。我们进行了两个互补的瞬时测定：用CRISPR/Cas9敲除Nix导致在很大程度上女性化的遗传男性和性分化的两个关键调节因子的雌性同种型的产生; Nix的异位表达导致具有几乎完整的男性生殖器的遗传女性。因此，Nix是启动男性发育所必需的，也是足够的。在这项研究中，我们将追求以下具体目标： 1)确定Nix转基因是否足以将雌性转化为可育雄性，并利用Nix转基因作为Ae性别分离和种群减少的手段。2）阐明Nix功能的分子机制; 3）研究Nix的物种分布、进化和功能保守性。

 DESCRIPTION (provided by applicant): Aedes aegypti is a major vector for dengue, yellow fever, and chikungunya viruses. The global incidence of dengue has increased dramatically in recent decades and nearly half of the world population is now at risk. No specific treatment for dengue exists and current prevention depends solely on effective vector control, which is hindered by increasing insecticide- resistance. Novel control strategies, informed by improved understanding of mosquito biology, are urgently needed. The long-term objective of this research is to decipher the mechanism of sex-determination in Ae. aegypti and translate such fundamental knowledge into safe and efficient methods to control mosquito-borne infectious diseases. Only female mosquitoes feed on blood and transmit pathogens. Thus maleness is the ultimate disease-refractory trait. Genetic evidence suggests that sex determination in aedine mosquitoes is governed by a dominant male-determining factor (M factor) that resides in the M-locus of a homomorphic sex- determining chromosome. Despite its importance as the master switch of sex-determination in many insects including mosquitoes, no M factor had been determined. Overcoming several technical bottlenecks, we have recently identified an M factor in Ae. aegypti we called Nix. Nix exhibits early embryonic expression and is the only gene that is persistently linked to the M- locus. We performed two complementary transient assays: Nix knockout with CRISPR/Cas9 resulted in largely feminized genetic males and the production of female isoforms of two key regulators of sexual differentiation; ectopic expression of Nix resulted in genetic females with nearly complete male genitalia. Thus, Nix is both required and sufficient to initiate male development. In this study, we will pursue the following specific aims: 1) Determine whether a Nix transgene is sufficient to convert females into fertile males and exploit Nix transgenics as a means for sex separation and population reduction of Ae. aegypti, 2) Elucidate the molecular mechanism underlying Nix function, and 3) Examine the species distribution, evolution, and functional conservation of Nix.