Function of a novel male-specific gene in Aedes aegypti

描述(申请人提供)：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。根据世界卫生组织的数据，近几十年来，全球登革热发病率急剧上升，世界上近一半的人口现在处于危险之中。目前没有针对登革热的特效药，目前的预防完全依赖于有效的病媒控制。然而，随着抗药性的增加，媒介控制方法受到威胁。迫切需要新的战略来抗击登革热和其他蚊媒疾病。目前正在探索几种抑制或取代媒介种群的遗传策略。由于只有雌性蚊子叮咬和传播病原体，因此最好释放雄性蚊子，而且可能需要释放雄性蚊子才能实施这些战略。更好地理解性别决定途径将为干扰提供新的靶点，并导致几个实际应用。例如，可以获得有条件地杀死雌性蚊子的转基因品系，这将比目前的方法提供更具成本效益和更具规模的仅针对雄性蚊子的生产。在实现种群减少方面，释放这种转基因雄性比释放不育雄性更有效。然而，除了一些高度保守的基因，如双性(Dsx)和转换器2(Tra2)外，人们对蚊子的性别决定知之甚少。伊蚊的雄性发育是由位于1号染色体上的一个显性雄性决定基因(M基因座)启动的，但目前尚无M基因座基因的报道。我们最近在Ae中发现了一个新的男性特异基因。埃及伊蚊，我们给它取名为NIX。物理作图将NIX定位在M基因座上，而NIX基因组DNA从未在任何女性身上检测到。当对5000多个后代进行筛查时，没有检测到NIX与M基因座之间的重组。NIX在早期胚胎、幼虫、蛹和成年雄性睾丸中表达，但在任何成年雌性组织中不表达。此外，预测的Nix蛋白是一种可能参与剪接的RNA结合蛋白。我们推测NIX在Ae的性别分化中起重要作用。埃及伊蚊。为了在这个探索性的R21项目中检验这一假设，我们将确定nix基因的异位表达(目标1)和敲除(目标2)的影响。为了确定这两种互补方法的结果，我们将监测一般表型和分子变化，并密切关注与性别分化相关的变化。我们预计将把我们的研究扩展到R21之外，以研究NIX功能的机制，并通过操纵NIX基因或其合作伙伴开发蚊子控制应用程序。

DESCRIPTION (provided by applicant): Aedes aegpyti is a major vector of dengue, yellow fever, and chikungunya viruses. According to the World Health Organization, the global incidence of dengue has increased dramatically in recent decades and nearly half of the world population is now at risk. There is no specific treatment for dengue and current prevention depends solely on effective vector control. However, vector control methods are under threat as insecticide-resistance increases. New strategies to combat dengue and other mosquito-borne diseases are urgently needed. Several genetic strategies to suppress or replace vector populations are being explored. Since only female mosquitoes bite and transmit pathogens, the release of males is preferred and possibly required for implementation of these strategies. A better understanding of the sex-determination pathway will provide novel targets for interference and lead to several practical applications. For example, transgenic lines may be obtained that confer conditional female lethality, which will provide more cost-effective and scalable production of male-only mosquitoes than current approaches. Release of such transgenic males is more effective at achieving population reduction than sterile male release. However, little is known about sex determination in mosquitoes except for a few highly conserved genes such as doublesex (dsx) and transformer2 (tra2). Male development in Aedes mosquitos is initiated by a dominant male-determining locus (M-locus) located on the chromosome 1. However, no M-locus genes have been reported. We recently identified a novel male-specific gene in Ae. aegypti, which we named nix. Physical mapping places nix at the M-locus and nix genomic DNA was never detected in any female. No recombination was detected between nix and the M-locus when more than 5000 offspring were screened. Nix is expressed in the early embryo, larvae, pupae, and adult male testis, but not in any adult female tissues. Furthermore, the predicted NIX protein is an RNA-binding protein which may be involved in splicing. We hypothesize that nix plays an important role in sexual differentiation in Ae. aegypti. To test the hypothesis during thi exploratory R21 project, we will determine the effect of both ectopic expression (Aim 1) and knockout (Aim 2) of the nix gene. To determine the outcome of the two complementary approaches, we will monitor general phenotypic and molecular changes and pay close attention to those related to sexual differentiation. We anticipate extending our research beyond this R21 to investigate the mechanism of nix function and develop mosquito control applications through manipulation of the nix gene or its partners.