Expression And Regulation Of CD63 Gene In Mouse Uterus During Peri-implantation Period

Embryo implantation is a complex process in which the reciprocal interaction between the implantation-competent blastocyst and receptive uterus is essential.After the establishmen of implantation,endometrial stromal cells begin to undergo decidualization for the subsequent embryo development and placentation.Implantation and decidualization are regulated by many factors,but the precise mechanism is largely unknown.In our serial analysis of gene expression(SAGE) analysis,CD63 was significantly higher in mouse uterus at inplantation sites than that at inter-implantation sites.CD63 antigen belongs to the transmembrane 4 superfamily(TM4SF),and plays a role in many tumors including melanoma,so it is known as a tumor metastasis suppressor gene.In this study,the expression pattern and regulation of CD63 gene in mouse uterus during peri-implantation period were investigated by in situ hybridization,real-time PCR,western blot and luciferase activity assay. Our results showed that both uterine CD63 mRNA and protein levels were highly expressed at implantation sites on day 5 of pregnancy,and CD63 mRNA signal was strongly detected in the decidual zone on the following days 6-8 of pregnancy.In the uterus on day 5 of pseudopregnancy or under delayed implantation,the expression signal of CD63 was hardly to be detected,but there was a specific expression after the activation of delayed implantation. Meanwhile,the pattern was similar with that on day 5 of pregnancy.In the uterus stimulated by artificial decidualization,a strong expression signal of CD63 was also detected in decidualizacial cells by in situ hybridization and real-time PCR. This implied that CD63 may involve in decidualization.Steroid hormonal treatments were not able to induce the expression of CD63 in uterus of ovariectomized mice.CD63 expression was upregulated in stromal cells decidualized in vitro.In cultured stromal cells and NIH-3T3 cells,the activity of CD63 gene promoter was significantly upregulated by the transcription factor C/EBPβ.These data demonstrated that the expression of CD63 in uterus was highly associated with implantation in a blastocyst-dependent manner.CD63 expression was upregulated in stromal cells decidualized in vitro,suggesting that CD63 may play a role during decidualization.In addition,the activity of CD63 gene promoter was upregulated by the transcription factor C/EBPβ.