Abstract: Objective To investigate the expression of activating transcription factor4 (ATF4) gene in mouse endometrium during peri-implantation process of embryos, and the role in the embryonic implantation. Methods Endometrium samples were collected from Day 0 to Day 7 in early pregnant mice, and the express level of ATF4 mRNA on it was determined by RT-PCR and the expression level of ATF4 protein as determined by immunohistochemistry and Western blotting.Polyclonal antibody of ATF4 was injected into the uterus of the early pregnant mice to observe the changes of the embryos. Results 1)It was demonstrated that the expression of ATF4 on the endometrium of pregnant mice was stronger than that of nonpregnant mice(P<0.05), and the tendency was gradually augmented as days went.It reached the highest level at pregnant d 4 and declined gradually thereafter. 2)The clearest expression of ATF4 protein was primarily limited to the subluminal stromal cytoplasm in the endometrium of mouse. Expressional mode of ATF4 protein was similar with that of the mRNA. 3)ATF4 antibody resulted in a significant decrease of embryo implantation as compared with the control group. Conclusions ATF4 gene may be involved in the decidualization, and promote the embryo implantation .

Key words: ATF4, implantation , endometrium, decidualization