Figure 6.
c-Myc Competes HNF4α Off the Distal and Proximal Sp1 Sites of the p21 Promoter
ChIP assays using HepG2 cells transfected with Flag.c-Myc expression vector (+) or empty vector (−), the anti-HNF4α antibody (H4, α-445), and the p21 primer sets described in Fig. 3A. All ChIPs were done on cells in 150-mm plates transfected with 12 μg Flag.c-Myc vector except those indicated with an asterisk, which were done on cells transfected with 24 μg Flag.c-Myc. The bands were quantified using the NIH Image J program, and the ratio of HNF4α1 binding signal from cells ectopically expressing c-Myc to those not ectopically expressing c-Myc (+Myc/−Myc) was calculated.