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。精子发生是动物中最特化和结构最复杂的细胞之一，是一个动态的发育过程，在这个过程中，生殖系在不同的阶段之间经历了3个受控的形态发生转变：从有丝分裂的精原细胞到减数分裂的精母细胞，从减数分裂的精母细胞到精子细胞，从精子细胞到成熟精子。我提议的NSERC资助的研究项目采用遗传方法来研究精子发生的发育过程。******到目前为止，体细胞在精子发生发育过程中的确切作用还没有被系统地探讨过。为了解决这个问题，我们最近进行了一次大规模的基因筛选，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很好的遗传可处理的体内模型系统来探索精子发生。******我们的基因筛选，是迄今为止进行的同类中最大的，确定了体细胞中生育所需的基因。筛选了2500多个单链RNAi系，代表2000多个基因。详细分析了候选基因的表型，以确定精子发生停止的时间。生物信息学分析揭示了几个功能基因类在我们的候选集合中被过度代表。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与精原细胞、精母细胞和精母细胞的发育相对应。******我的NSERC提案将提供精子发育的详细机制见解：我们将在功能上表征在体细胞中起作用的基因网络，以介导从有丝分裂的精原细胞到减数分裂的精母细胞，从减数分裂的精母细胞到精子，以及从精子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)利用遗传学和实时成像的结合，我们将确定胞吞调节因子在调节精子发育的细胞信号中的作用。******b)利用遗传学和实时成像的结合，我们将确定体细胞中细胞极性基因在精子细胞发育背后的形态发生事件中的作用。******c)结合遗传学和实时成像，我们将阐明分子马达和基于微管的转运在精细胞形态发生过程中的作用。******

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.******