Mechanisms of sex determination in Anopheles and their implementation to control mosquito vectors

决定动物性别的分子发育过程变化多端，令人吃惊。由于控制这些过程的基因经常经历快速变化，在一个物种中收集到的性别决定途径组成部分的信息可能很少或根本没有提供线索，以促进在其他更远亲的物种中识别性别决定基因。在昆虫中，这一途径在果蝇（Drosophila melanogaster）中被详细描述；然而，尽管做出了努力，但在包括蚊子在内的其他昆虫群体中，它仍未被探索或知之甚少。最近，我们在疟蚊冈比亚按蚊（Anopheles gambiae）中发现了一个位于雄性特异性Y染色体上的基因（名为Yob），它控制着个体向雄性的发育。令人惊讶的是，如果在女性发育的早期阶段表达（激活），Yob会杀死女性胚胎。Yob调控雄性发育并杀死雌性的机制尚不清楚。为了填补这些知识空白，我们提出了一个广泛的，高通量的基因序列数据的探索在冈比亚拟虫的发展活跃。我们小组已经生成了数据，并在从早期胚胎到成年的多个时间点分别收集了雄性和雌性的数据，这些数据将被过滤，以识别可能参与上述过程的性别特异性表达基因。与此同时，我们将对转基因蚊子进行分子研究，在雄性蚊子中灭活Yob，在雌性蚊子中激活Yob，以检测表达紊乱的基因，表明它们与Yob直接或间接相互作用。这些转基因菌株是我们小组最近产生的，可用于本研究。已确定的基因在按蚊性发育中的作用将通过一些实验方法进行测试。我们还将确定冈比亚疟蚊基因组中激活早期胚胎基因表达所需的DNA调控区域，并评估其在转基因蚊子中的功能。我们的研究将有助于理解昆虫的性别决定途径，并有望对新的蚊虫控制策略产生重大影响。性别决定基因，当在转基因技术中被操纵时，可以被用来消除雌性，产生只有雄性的后代，导致雌性死亡，或者可能导致基因上的雌性逆转为雄性。在更广泛的背景下，本研究的成果将有助于鉴定其他害虫物种的性别决定基因，包括虫媒病毒的蚊子载体，并将刺激对这些昆虫群体的遗传控制研究的新途径。

The molecular developmental processes that determine gender in animals are astonishingly variable. Because genes governing these processes often undergo rapid changes, information on the components of the sex determination pathway gathered in one species may provide little or no clue to facilitate identification of the sex determination genes in other, more distantly related, species. In insects, the pathway has been characterised in detail in the fruit fly Drosophila melanogaster; however, despite efforts, it remains unexplored or poorly understood in other insect groups, including mosquitoes. Recently, we have identified a gene (named Yob), which in the malaria mosquito, Anopheles gambiae, is located on the male-specific Y chromosome and controls the development of an individual into a male. Surprisingly, Yob kills female embryos, if expressed (activated) during early steps of female development. The mechanisms through which Yob regulates male development and kills females remain unknown. To fill these knowledge gaps, we propose exploration of an extensive, high-throughput sequence data of genes active during the development of A. gambiae. The data, already generated by our group and collected separately for males and females at a number of time points, starting from early embryos to adults, will be filtered to identify sex-specifically expressed genes that may be involved in the mentioned above processes. In a parallel approach, we will perform a molecular study of genetically modified mosquito strains, with Yob either inactivated in males, or activated in females, to detect genes with perturbed expression, indicative of their direct or indirect interaction with Yob. Such transgenic strains were recently generated by our group and are available for this study. The role of the identified genes in sexual development of Anopheles will be tested by a number of experimental approaches. We will also identify DNA regulatory regions in the A. gambiae genome necessary to activate gene expression in early embryos, and evaluate their function in transgenic mosquitoes. Our proposed research will significantly contribute to the understanding of insect sex determination pathways, and is expected to have a great impact on novel strategies of mosquito control. The sex determination genes, when manipulated in transgenic technology, could be used to eliminate females and produce male-only generations by causing female lethality or, potentially, sex reversal of genetic females into males. In a broader context, the outputs of this study will facilitate identification of sex determination genes in other insect pest species, including mosquito vectors of arboviruses, and will stimulate new avenues of research on genetic control of these insect groups.