小鼠精母细胞I-SceI报告系统的建立及在DNA双链断裂同源重组修复研究的应用

不育已经成为一个严重的健康问题，育龄夫妇中发病率高达15%。近年来，男性不育的治疗虽然取得了较大进展，但是其分子遗传学机制仍未阐明。减数分裂同源重组过程与男性生育、基因组的完整性有着密切关系，其异常会导致不同程度的精子异常，如精子发生停滞而出现不育，或精子染色体异常导致非整倍性变异。染色体的交换起始于蛋白SPO11形成DNA双链断裂。减数分裂同源重组具有位点多，而且存在热点和冷点的不平衡，这给DNA双链断裂同源重组修复的分子机制研究带来了巨大挑战。本研究拟通过在细胞和动物中构建精母细胞I-SceI报告系统，产生位点特异的DNA双链断裂，并将其应用到DNA双链断裂同源重组修复信号通路研究。I-SceI报告系统在小鼠精母细胞中的建立有望为特发性男性不育分子机制阐明提供新的有效的研究工具。

Infertility is a major health problem that affects approximately 15% of couples. Although many advances have been made in the treatment of male infertility, the molecular and genetic causes of male infertility remain largely elusive. The process of meiotic recombination is essential for fertility and integrity of the genome. Altered recombination may result in various sperm abnormalities, such as arrest in spermatogenesis or non-disjunction, which in turn contributes to infertility or aneuploidy. Chromosomal crossover often begins when a protein called SPO11 makes a targeted double-strand break in DNA. Meiotic recombination events are distributed unevenly throughout eukaryotic genomes including hotspots and coldspots, which brings great challenge to molecular mechanism research of homologous recombination-mediated repair of DNA double-strand breaks. In this study, we construct an I-SceI reporter system in mouse spermatocytes to induce a site-specific DNA double-strand breaks, and apply the cell model and animal model to signal transduction involved in homologous recombination-mediated repair of DNA double-strand breaks. The I-SceI reporter system in mouse spermatocytes could provide us with a new and practical tool for elucidating molecular mechanism of non-obstructive azoospermia.