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3D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。精子发生产生动物中最特化和结构最复杂的细胞之一，并且是一个动态发育过程，其中生殖细胞在离散阶段之间经历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，以及从精子细胞到成熟精子。我提议的NSERC资助的研究计划采用遗传学方法来研究精子发生的发育程序。迄今为止，索马在精子发生的发育过程中的确切作用尚未得到系统的研究。为了解决这个问题，我们最近进行了一个大的遗传筛选，以确定基因所需的果蝇睾丸体细胞的精子发育。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学上易于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最大规模的基因筛选，确定了体细胞生育所需的基因。筛选了代表超过2000个基因的超过2500个单一RNAi株系。候选基因的表型进行了详细分析，以确定何时精子发生停滞。生物信息学分析发现了几个功能基因类，这些基因在我们的候选人集合中过度代表。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转运相关的基因分别与精原细胞、精母细胞和精子细胞的发育相对应。** 我的NSERC提案将提供对精子发育的详细机制见解：我们将功能性地表征在索马中起作用的基因网络，这些基因网络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成这些转变的机制。我们的主要目标是：**a）结合遗传学和活体成像，我们将确定索马中的内吞调节因子在调节精原细胞发育的细胞信号中的作用。** B）结合遗传学和活体成像，我们将确定索马中细胞极性基因在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，我们将阐明精子细胞形态发生过程中索马中分子马达和微管转运的作用。**

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.******