Unraveling The Proteomic Profile Of Mice Testis During The Initiation Of Meiosis And Preliminary Functional Study

Meiosis is unique to germ cells of cell division process. Many genes and proteins are closely related with the initiation of meiosis. In mice, once primordial germ cells(PGCs) are generated, they continue to proliferate and migrate to eventually reach the future gonads. They initiate sexual differentiation after their colonization of the gonads. During this process, retinoic acid(RA) induces meiosis in the female germ cells, which proceeds to the diplotene stage of meiotic prophase I, whereas the male germ cells initiate growth arrest. After birth, meiosis is initiated in mice spermatogonia by their conversion to preleptotene spermatocytes. There are evidences showing the roles of RA in the regulation of spermatogonial differentiation and meiosis initiation. However, it is still not well known on what responds to RA and how RA signaling engages meiosis.Thus, we constructed a proteomic profile of proteins associated with meiosis onset during testis development in mouse and identified 104 differentially expressed proteins(≥1.5 folds). Bioinformatic analysis showed proteins functioning in specific cell processes. The expression patterns of five selected proteins were verified via Western Blot, and their relationship with RA signaling was further investigated by qRT-PCR. Finally, we explored the cellular localization of PDCD4, whose role in spermatogenesis is not well known. Taken together, the results provide an important reference profile for further functional study of meiosis initiation, and a large number of potential molecular targets for clinical treatment of male infertility.