The effects of Nanos2 on Boule and Stra8 in male germline stem cells (mGSCs).

The mitosis–meiosis switch is a key event in the differentiation of germ cells. Meiosis is important in development biology, however, it has not been clear what is the regulation mechanism in mammals. Our previous study showed that Boule could activate Stra8 directly and result in the meiosis initiation of dairy goat male germline stem cells (mGSCs). Nanos2, a RNA-binding protein, plays critical roles in the suppression of meiosis by preventing Stra8 expression and maintain the male germ cell development. The main purpose of this study was to explore whether Nanos2 represses Stra8 transcription through Boule or not. We found ectopic over-expression of Nanos2 in GC-1 and mGSCs down-regulated Stra8 transcription and translation, and Boule expression was not affected. It was in consistent with our expectation that RA could up-regulate Boule and Stra8 expression, but down-regulate Nanos2 expression in mGSCs. In dairy goat, the expression levels of Boule and Stra8 would rise with the increase of age, but the expression level of Nanos2 in 90 dpp and adult testis had not shown a clear change. In conclusion, Nanos2 represses Stra8 expression but not through Boule in dairy goat mGSCs.