The Expression And Localization Of BCAS2 In Mouse Granulosa Cell And Oocyte, And The Effect On Granulosa Cell Proliferation And Apoptosis

BCAS2 plays a critical role in mammalian follicle development. BCAS2 is a coactivator of estrogen receptor, and the expression of BCAS2 is a key regulator of ER-mediated gene transcription. And studies of BCAS2 are in cancer cell line(eg. MCF-7 cell and He La cell), however, the role of BCAS2 in normal somatic cells and germ cells has not been well studied. In this study, the main objective was to detect the expression of BCAS2 in mouse ovarian tissue and functional study of BCAS2 in mouse granulosa cells, through the technology like immune-fluorescence, Western blot, and real-time PCR. The results were described as follows:(1) The localization and expression of BCAS2 in mouse granulosa cells and oocytes. The immunofluorescence analysis revealed a nuclear localization in both granulosa cells and oocytes. Western blot showed that the expression of BCAS2 in GV-MII oocytes gradually increased. And the expression level of BCAS2 in mouse ovaries pecked at PMSG injection for 6 h and 12 h were significantly higher than other period(P<0.05). Real-time PCR result indicated the expression of BCAS2 in preantral follicles was significantly higher than that in antral follicles(P<0.05).FSH can promote the BCAS2 m RNA expression in granulosa cells.(2) Role of BCAS2 inproliferation and apoptosis of granulosa cell. After knockdown of BCAS2 by RNAi, the proliferation down-regulated significantly(P<0.05), and the expression of PCNA significantly reduced(P<0.05). Meanwhile, Knockdown of BCAS2 in granulosa cells up-regulated bax m RNA, while down-regulated the bcl-2 m RNA significantly(P<0.05).In conclusion, our study indicated that BCAS2 was localizated in the nuclear of both granulosa cell and oocyte. The expression pattern of BCAS2 in follicles was different, the expression of BCAS2 altered in different development stage follicles. Further results indicatied that knockdown of BCAS2 in granulosa cells reduced cell proliferation, while induced cell apoptosis, and the expression of genes related with cell proliferation and apoptosis was significantly affected after knockdown of BCAS2. All the results suggest that BCAS2 may participate in the regulation proliferation and apoptosis of granulose cell.