Objective    To identify mRNA and protein expression of tumor metastasis suppressor gene CD63/ME491 in mouse uterus during estrous cycle and early pregnancy

and to explore their effects during the process of embryonic implantation.     Methods    Protein and mRNA expression of tumor metastasis suppressor genes CD63/ME491 were detected by immunohistochemistry and RT-PCR.     Results    During estrous cycle

CD63/ME491 mRNA expression was most during diestrus

while was least during estrus. However

protein was expressed most during proestrus and diestrus

and strongly positive in both endometrial epithelial cells and stroma cells. CD63/ME491 mRNA was expressed in the mouse uterus during pregnancy day 1 to 8

and the expression quantity reached the maximum on pregnancy day 4 when embryo started implantation

then maintained at high level. CD63/ME491 protein was expressed in the mouse endometrial luminal epithelial cells and gland cells during pregnancy day 1 to 6

while its level dynamically changed in the stroma cells

negative on day 1

weakly positive in the subepithelial stroma cells on day 2

gradually increased in quantity and range from day 3 to 8.       Conclusion    Spatiotemporal expression of CD63/ME491 in mouse uterus during embryo implantation indicated its role in regulation of embryo cells invasion to endometrium.