CAREER: Genetic and Molecular Analysis of Spermatogenesis of Caenorhabditis Elegans

秀丽隐杆线虫（Caenorhabditis elegans）是自由生活的线虫，是最具特征的后生动物之一，它可以适应许多最强大的遗传技术。因此，它是研究包括减数分裂在内的许多发育过程的合适实验生物。男性和女性减数分裂有许多细胞学上的差异。在男性减数分裂中，精子细胞通常经历两次相等的分裂，形成四个精子。另一方面，在雌性中，减数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。一些突变筛选已经发现了大量的精子发生缺陷突变。这些突变体的形态学特征导致鉴定出一组有缺陷的初级精母细胞，无法完成减数分裂。突变体分为10个不同的互补组（早期作用的Spe基因）。本研究的具体目的是对Spe -25基因进行遗传、表型和分子表征，初步鉴定表明该基因是最早起作用的Spe基因之一。它已经被映射到染色体III的一个很好的表征区域，应该优化分子表征。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异性减数分裂事件的认识。此外，建议的实验特别适合本科生参与“动手”的实验室环境。

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.