CAREER: Genetic and Molecular Analysis of Spermatogenesis of Caenorhabditis Elegans

自由生活的线虫，秀丽线虫，是最具特征的后生动物之一，它服从于许多可用的最强大的基因技术。因此，它是研究包括减数分裂在内的许多发育过程的合适的实验有机体。雄性和雌性减数分裂有许多细胞学上的差异。在雄性减数分裂中，精母细胞通常经历两次相等的分裂，形成四个精子细胞。另一方面，在雌性，小母细胞经历不平等的细胞分裂，导致卵子和极体的形成。这些差异的生化基础尚不清楚。几个突变筛选已经发现了大量在精子发生方面有缺陷的突变。这些突变体的形态特征导致鉴定出一组初级精母细胞有缺陷，未能完成减数分裂。突变体分为10个不同的互补组(早期作用的SPE基因)。这一建议的具体目的是从遗传学、表型和分子特征上确定spe-25基因，初步特征表明该基因是最早起作用的spe基因之一。对模式生物中这些基因的分析将增强我们对后生动物中雄性特有减数分裂事件的了解。此外，建议的实验特别适合本科生参与到“动手”的实验室环境中。

Varky9734584The free-living nematode, Caenorhabditis elegans, is one of the best-characterized metazoans and it is amenable to many of the most powerful genetic technologies available. It is, therefore, an appropriate experimental organism for the study of many developmental processes, including meiosis. There are a number of cytological differences between male and female meiosis. In male meiosis, spermatocytes normally undergo two equal divisions leading to the formation of four spermatids. In females, on the other hand, the meiocytes undergo unequal cell division leading to the formation of an ovum and the polar bodies. The biochemical basis for these differences is not known. Several mutation screens have identified a large number of mutants defective in spermatogenesis. Morphological characterization of these mutants led to the identification of a group with defective primary spermatocytes that failed to complete meiotic division. The mutants fall into ten different complementation groups (early acting Spe genes). The specific aims for this proposal are to genetically, phenotypically and molecularly characterize the spe-25 gene, a gene which preliminary characterization suggests is one of the earliest acting Spe genes. It has been mapped to a well-characterized region of chromosome III that should optimize the molecular characterization.The analysis of these genes in a model organism will enhance our knowledge of the male specific meiotic event in a metazoan organism. Moreover, the proposed experiments are particularly suited for the involvement of undergraduate students in a "hands-on" laboratory environment.