Genetic analysis of the cell biological basis of sperm morphogenesis.

我研究的总体目标是了解细胞和组织如何通过形态发生过程发展其复杂的三维结构。我的实验室用来研究形态发生的一个关键模型是精子发生，即产生精子的过程。精子发生是动物体内最特殊和结构最复杂的细胞之一，是一个动态的发育过程，生殖系在不同的离散阶段之间经历3次受控的形态发生转变：从有丝分裂精原细胞到减数分裂精母细胞，从减数分裂精母细胞到精子细胞，从精子细胞到成熟精子。我提出的NSERC资助的研究项目使用遗传学方法来研究精子发生的发育程序。到目前为止，体细胞在调节精子发生的发育程序中的确切作用还没有被系统地探索。为了解决这个问题，我们最近进行了一项大型遗传筛查，以确定果蝇睾丸体细胞中精子发育所需的基因。我们的实验室使用苍蝇睾丸作为模型，因为它们提供了一个出色的遗传易处理的体内模型系统来探索精子发生。*我们的基因筛查是迄今为止进行的同类筛查中规模最大的一次，它确定了体细胞中生育所需的基因。筛选了代表2000多个基因的2500多个单RNAi株系。对候选基因的表型进行了详细分析，以确定何时精子发生停止。生物信息学分析揭示了几个功能基因类别，它们在我们的候选集合中有过高的代表性。重要的是，特定的基因类别与特定的发育转变有关。例如，与内吞作用、细胞极性和基于微管的运输相关的基因分别对应于精原细胞、精母细胞和精子细胞的发育。*我的NSERC建议将提供对精子发育的详细机制洞察：我们将从功能上描述在体细胞中起作用的基因网络，这些基因网络介导从有丝分裂精原细胞到减数分裂精母细胞、从减数分裂精母细胞到精子细胞以及从精子细胞到成熟精子的发育转变。这将揭示每个特定基因网络促进这些转变的机制。我们的主要目标是：*a)结合遗传学和实时成像，我们将确定胞体内吞调节因子在调控精原细胞发育的细胞信号中的作用。*b)结合遗传学和实时成像，我们将确定胞体中的细胞极性基因在支持精母细胞发育的形态发生事件中的作用。*c)结合遗传学和活体成像，我们将阐明分子马达和基于微管的运输在精子细胞形态发生过程中在胞体中的作用。

The overall goal of my research is to understand how cells and tissues develop their complex 3-D architecture through the process of morphogenesis. A key model my lab uses to study morphogenesis is spermatogenesis, the process of producing sperm. Spermatogenesis produces one of the most specialized and architecturally complex cells in animals and is a dynamic developmental process wherein the germline undergoes 3 controlled morphogenetic transitions between discrete stages: from mitotic spermatogonia to meiotic spermatocytes, from meiotic spermatocytes to spermatids, and from spermatids to mature spermatozoa. The NSERC funded research program I propose employs genetic approaches to investigate the developmental program of spermatogenesis.******To date, the precise role of the soma in mediating the developmental program of spermatogenesis has not been systematically explored. To address this we recently carried out a large genetic screen to identify genes that are required in the somatic cells of Drosophila testis for sperm development. Our lab uses the fly testes as a model since they provide an excellent genetically tractable in vivo model system to explore spermatogenesis. ******Our genetic screen, the largest of its kind carried out to date, identified genes required in somatic cells for fertility. Over 2500 single RNAi lines representing over 2000 genes were screened. The phenotype of candidate genes was analysed in detail to determine when spermatogenesis arrested. Bioinformatic analysis uncovered several functional gene classes that were over-represented in our collection of candidates. Importantly, particular gene classes were associated with specific developmental transitions. For example genes associated with endocytosis, cell polarity, and microtubule-based transport corresponded with the development of spermatogonia, spermatocytes, and spermatids, respectively. ******My NSERC proposal will provide detailed mechanistic insight into sperm development: We will functionally characterize the gene networks that act in the soma to mediate the developmental transitions from mitotic spermatogonia to meiotic spermatocytes, from meiotic spermatocytes to spermatids, and from spermatids to mature spermatozoa. This will reveal the mechanism by which each specific gene network contributes to these transitions. Our main aims are:******a) Using a combination of genetics and live imaging we will determine the role of endocytotic regulators in the soma in modulating cell-signals that regulate spermatogonial development.******b) Using a combination of genetics and live imaging we will determine the role of cell polarity genes in the soma in the morphogenetic events that underlie spermatocyte development. ******c) Using a combination of genetics and live imaging we will elucidate the role of molecular motors and microtubule-based transport in the soma during spermatid morphogenesis.******