线粒体融合蛋白MFN2在精子发生过程中的作用及机制研究

哺乳动物精子发生是个极其复杂的生物学过程，涉及了很多睾丸特异或优势表达基因对其进行调控。尽管国内外学者已发现了一些基因参与调控精子发生，但其具体的调控作用机理仍然不十分清楚。申请人在前期的工作中发现线粒体融合蛋白基因Mfn2在小鼠睾丸中优势表达，并在精母细胞和圆形精子中高度表达，因此推测Mfn2基因参与调控小鼠精子发生过程。本课题拟利用Cre-Loxp敲除策略构建两种不同的生殖细胞条件性敲除Mfn2小鼠模型：1）Stra8-Cre介导的Mfn2敲除小鼠；2）Ddx4-Cre介导的Mfn2敲除小鼠，通过观察比较这两种条件性敲除小鼠表型的异同，确定Mfn2在精子发生过程中的作用，并进一步探寻与其相互作用的因子，以揭示Mfn2在调控精子发生过程中的具体机制。通过本课题的研究，可望阐明线粒体融合蛋白MFN2在精子发生过程中的遗传作用机制，为基因突变导致的精子发生障碍的靶向治疗提供新的理论基础。

Spermatogenesis is a complicated biological process in mammals, which involved in a large number of testis-specific and/or preferential gene expression regulation. Although lots of genes were identified by many of investigators are believed to control or regulate spermatogenesis, the genetic mechanism of gene regulation during spermatogenesis is largely unknown. We previously found that the transcript of Mitofusin 2 (Mfn2) was expressed in mouse testes preferentially and highly expressed in pachytene spermatocytes and round spermatids. Based on these expression profiles of Mfn2, we hypothesized that Mfn2 is essential for regulation of spermatogenesis. In this project, we are going to utilize the Cre-Loxp knock-out strategy to obtain two types of Mfn2 conditional knock-out mouse models to inactivate Mfn2 from different stage of male germ cells. One is Stra8-Cre mediate Mfn2 knock-out mouse model, another is Ddx4-Cre mediate Mfn2 knock-out mouse model. We will characterize the phenotype differences of these two types of Mfn2 conditional knock-out male mice to identify the roles of Mfn2 during spermatogenesis, and further reveal the functions and mechanism of Mfn2 in spermatogenesis. It is hope that a better understanding on how can Mfn2 genetically control spermatogenesis and what is the mechanism of Mfn2 regulation, and will be helpful to provide a new evidence and theory for gene target therapy on aberrant spermatogenesis caused by gene mutation.