Objective:To identify the role of transcription factors Sp1 and Sp3 in the expressional regulation of ezrin in human esophageal carcinoma cells.Methods:Esophageal carcinoma EC109 cells were transfected with expressing vectors CMV-Sp1 or CMV-Sp3,and the effect of Sp1 and Sp3 over-expression on ezrin mRNA and protein expression was determined by real time RT-PCR and Western blot analysis.Furthermore,EC109 cells were cotransfected with the ezrin promoter-directed luciferase reporter vector and control vector pRL-TK along with transcription factor expression vector.The roles of Sp1 and Sp3 in ezrin promoter activation and whether this activation occurred through the Sp1 binding site,-75/-69,were analyzed by dual-luciferase reporter assay system.Results:Over-expression of transcription factors Sp1 and Sp3 significantly increased the expression of ezrin mRNA and protein and the ezrin promoter activity in EC109 cells.Sp1 and Sp3 enhanced the promoter activity through different binding sites and only Sp1 did that through the-75/-69 site.Conclusion:Sp1 and Sp3 can regulate ezrin expression in EC109 cells.

AIM: To set the model of rat bone marrow me se nchymal stem cells (BMMSCs) that differentiate into cardiomyocytes and observe t he connection structure between cells. METHODS: BMMSCs were isolated by adhering to culture plates and cultured in vitro to expand. Induction of BMMSCs to differentiate into cardi omyo cytes was conducted by treating the cells with 5-aza. Immunocytochemical stainin g was used to identify sarcomeric actin and intercalated disc-like structure wh en the cells were cultured for additional 1 week, 2 or 3 weeks, respectively. RESULTS: Sarcomeric actin positive cells were observed in 1 week , 2 or 3 weeks after 5-aza treatment. Some cells stained positive for connexin4 3 at 1 week and 2 weeks after 5-aza treatment, with brown pellet located disper sively around nucleus. 3 weeks after 5-aza treatment, connexin43 positive cells s howed brown pellet arranging in thready structure around nucleus, such structure could be seen between very few cells which was similar to intercalated disc-lik e structure in normal heart tissue. CONCLUSION: During the process of BMMSCs differentiating into ca rdiomyocytes, intercalated disc-like structure is gradually formed with increas e in culture time and cell density.