UHRF1调控转座子沉默和雄性生殖细胞发育的作用及机制研究

In recent years, how epigenetics regulates germ cell development has become a research hotspot. UHRF1, as an important epigenetic factor, regulates DNA methylation to maintain normal physiological functions. It has been found that UHRF1 can regulate the oocyte development, but its research on the development of male germ cells has not been reported. In our previous studies, we found that knocked out of Uhrf1 specifically in mouse male line can lead to arrest of germ cell development and complete male sterility, and the abnormal activation of transposon elements. Therefore, we assumed that UHRF1 may maintain the normal development of male germ cells by silencing transposon. This project intends to screen proteins interacted with UHRF1 by immunoprecipitation-mass spectrometry (IP-MS), explore the signaling pathways involved in UHRF1 through their interaction, and combine transcriptome and proteomics to further search the key signaling molecules downstream of UHRF1 in mediating the process of transposon silencing, which will elucidate the molecular mechanism by which UHRF1 regulates male germ cell development. This study aims to explore how UHRF1 can silence transposon to maintain the male germ cell development, and to provide the evidences of epigenetic regulation of UHRF1 in male germ cell development and the ideas for the treatment of male infertility.

近年来，表观遗传如何调控生殖细胞发育已成为研究热点。UHRF1作为重要的表观遗传因子能够调控DNA甲基化以维持机体正常生理功能。已有研究发现UHRF1能够调节卵母细胞发育，但其在雄性生殖细胞发育方面的研究尚未见报道。我们在前期研究中发现：小鼠雄性生殖细胞特异敲除Uhrf1导致生殖细胞发育停滞和雄性不育，且某些转座子被异常激活。因此申请人推测：UHRF1可能通过调控转座子沉默以维持雄性生殖细胞的正常发育。本项目拟利用免疫沉淀-质谱联用（IP-MS）技术筛选与UHRF1相互作用的蛋白，通过它们之间的互作关系探索UHRF1所参与调控的信号通路，并结合转录组及蛋白组学等方法进一步确定UHRF1在介导转座子沉默过程中的关键信号分子，从而阐明UHRF1调节雄性生殖细胞发育的分子机制。本项目旨在探索UHRF1如何通过调控转座子沉默以维持雄性生殖细胞正常发育的作用机制，为男性不育的诊治提供新的理论依据。

DNA甲基化是转座子（Transposable element，TE）沉默的主要调控机制。本研究发现睾丸高表达蛋白Uhrf1是TE沉默所必需的。Uhrf1的表达模式揭示了其在早期生殖细胞发育过程中的动态分布变化。uhrf1缺失严重影响精原细胞分化和减数分裂过程。在Uhrf1敲除的生殖细胞中，转座子的DNA甲基化水平明显降低。此外，我们发现Uhrf1能够与剪接因子DDX5和hnRNPH1相互作用，并调节与减数分裂相关的靶基因的选择性剪接。我们的研究结果表明，Uhrf1是一种关键的表观遗传调控因子，它可能是通过DNA甲基化沉默TE的关键蛋白，也是一种潜在的剪接因子并介导与精子发生相关的转录物的选择性剪接。