Figure 5.

p53 regulates miR-124 expression by binding its promoter. (a) pcDNA3.1/p53 vector was transfected into HT29, p53^+/+ HCT116 cell and p53^−/− HCT116 cell to achieve forced p53 expression in the presence or absence of PDT. (b) A schematic diagram of a potential p53 binding element in the promoter region of the miR-124 gene predicted by Jaspar database. A wt-miR-124 promoter luciferase reporter vector and a mut-miR-124 promoter luciferase reporter vector were constructed. (c–e) The indicated luciferase reporter vectors were co-transfected into HT29, p53^+/+ HCT116 cells and p53^−/− HCT116 cells with pcDNA3.1/p53 vector in the presence or absence of PDT. The luciferase activity was then determined by using dual luciferase assays. (f–h) The real-time ChIP assay showed that the level of p53 antibody binding to miR-124 promoter was much greater than that of IgG in the presence or absence of PDT. The data are presented as mean±S.D. of three independent experiments. **P<0.01, compared with the pcDNA3.1 group; ^#P<0.05, ^##P<0.01, compared with the p53+PDT (–) group