Expression and localization of meiosis-associated protein in gonads of female rats at different stages.

It was well known that a critical process of oogenesis in the female mammalian was the entry of mitotic oogonia into meiosis. Early studies from model animal mice suggested that the retinoic acid (RA) response signal protein STRA8 (stimulated by retinoic acid gene 8) and the meiosis-specific chromosomal behavior marker protein SCP3 (Synaptonemal Complex Protein 3) were two crucial molecular markers during meiosis. The expression of STRA8 and SCP3 at different stages in rat ovaries was investigated by immunohistochemistry, qRT-PCR and Western Blot. Immunohistochemistry results showed that STRA8 and SCP3 were mainly expressed in embryonic stage. And STRA8 was expressed in the cytoplasm and nucleus of the ovaries after birth. qRT-PCR and Western Blot results showed that the mRNA and protein levels of STRA8 and SCP3 were expressed in embryonic stage. The expression of STRA8 and SCP3 indicated germ cells enter meiosis in rats embryo, and STRA8 and SCP3 could serve as molecular markers for the meiosis in rats. The localization of STRA8 in the nucleus increased the possibility that STRA8 might act as transcription factor or activate transcription to function after birth.