Decrease of DNA methylation in HEK-293 cells overexpressing DNMT1 and PKCζ. (A) Western blot analysis showing expression of PKCζ and DNMT1 in HEK-293 transfected cells used in the analysis of methylated DNA Ip-on-Chip described in Materials and methods. (B) Histograms representing the methylation status of 15 genes selected from active regions as measured by qPCR using DNA immunoprecipated with an antibody against 5-methylcytosine. Untr12 was used as a control for a negative region. TRPA1 was used as a positive control. Copy number values were normalized for primer efficiency by dividing by the values obtained using input DNA and the same primer pairs. Error bars represent standard deviations calculated from the triplicate determinations. *, P < 0.05; **, P < 0.01.