FIG. 6.

β-Catenin, TCF4, and transcriptional regulatory factors assemble at the c-Myc 3′ enhancer prior to binding to the 5′ c-Myc promoter following exposure of arrested HCT116 cells to serum. (A) Real-time PCR analysis of ChIP assays using anti-β-catenin or anti-TCF4 antibodies to precipitate chromatin isolated from serum-starved cells (0) and starved cells released into serum for 1, 2, 4, or 8 h. Primers specific to the 5′ c-Myc promoter and the c-Myc 3′ enhancer (primer set 5 and set 13, respectively) (Fig. 2A) were used in the real-time PCRs. (B to D) Real-time PCR analysis as in panel A except that anti-TFIIB (B), anti-H3K4me3 (C), or anti-H3K9/K14ac (D) antibodies were used in the ChIP assays. Error bars indicate standard errors of the means.