The interactions of DNMT1 with the promoter regions of candidate genes following IR treatment. Chromatin immunoprecipitation (ChIP) assays were performed to determine the levels of DNMT1 at the promoter regions of candidate genes (ANGPT1, APBB2, CHGA, CTGF, IFI16, IGLON5, and SLC43A2) in HCT116 cells following 0.5 μM 5-aza-dC treatment or irradiation (2 or 5 Gy). GAPDH was used as negative control. Cross-linked and sheared chromatin was immunoprecipitated with an anti-IgG antibody (dark gray bar) or with anti-DNMT1 (light gray bar). The results are shown as a percentage of the input chromatin. Associated chromatin in the ChIP samples were quantified by real-time RT-PCR. The data represents the mean ± the standard deviation of triplicates. Representative data are shown from three independent trials. *P < 0.05; **P < 0.01; ***P < 0.001; TSS, Transcription Start Site.