精子发生过程中精母细胞减数分裂的顺利进行是确保单倍体精子生成的关键环节.申请人前期研究发现①线粒体膜蛋白Prohibitin(PHB)在小鼠精母细胞高表达;Phb生殖细胞特异性敲除小鼠雄性不育,无精子生成,精母细胞减数分裂在细线前期至细线期被阻断.②组蛋白H3Y41磷酸化(H3Y41ph)在小鼠细线期精母细胞高表达.③敲减小鼠GC2精母细胞Phb mRNA表达后,H3Y41ph水平显著降低.推测精母细胞表达的PHB可能通过调控H3Y41ph在减数分裂过程中发挥重要作用.因此,本项目将进一步寻找和鉴定精母细胞PHB所调控的下游相关基因和信号通路,以及PHB间接调控的H3Y41ph介导的下游相关基因,阐明精母细胞PHB通过调控H3Y41ph而影响精母细胞减数分裂的分子机制.本研究将有助于理解线粒体膜蛋白PHB调控生殖细胞发育和精母细胞减数分裂的表观遗传机制,为开发男性不育治疗方法提供理论支持.

It has been evidenced that meiosis of spermatocytes is a critical step for sperm production during spermatogenesis. Our previous studies show that (1) mitochondrial Prohibitin (PHB) is expressed higher in spermatocytes during mouse spermatogenesis. After deletion of PHB specifically in the male germ cells, Phb cKO mouse are male infertile, showing that meiosis of spermatocytes was blocked between the stages of pre-leptotene to leptotene at the prophase of meiosis I and accordingly no sperm are produced in seminiferous tubules. (2) The expression of phosphorylated histone H3Y41 (H3Y41ph) was found to be expressed higher in leptotene spermatocytes of mouse. (3) Knockdown of Phb mRNA significantly downregulate the level of histone H3Y41ph in the GC2 spermatocyte cell lines. Based on above findings, we proposed that mitochondrial PHB may play key roles on meiosis by the regulation of histone H3Y41ph in the spermatocytes. The objectives of this study, therefore, is to further explore and identify the downstream genes and signaling pathways directly regulated by PHB or histone H3Y41ph in the spermatocytes firstly. Secondly, to clarify what the downstream genes regulated by histone H3Y41ph are also controlled by PHB indirectly. Finally, to elaborate clearly the mechanism of PHB’s role on meiosis by the regulation of histone H3Y41ph in the spermatocytes. This study will help us to understand better about the epigenetic mechanism of mitochondrial PHB on meiosis during the development of male germ cells. The findings of this study could also support us theoretically on how to develop new therapy approach for male infertility.