Chromatin immunoprecipitations were performed with cross-linked chromatin from 4 x 10 6 HeLa cells starved overnight and treated with TPA (12-O-Tetradecanoylphorbol-13-Acetate) #4174 (100 ng/ml) for 3 hours, and either 5 μl of SRF1 (D71A9) XP ® Rabbit mAb or 2 μl of Normal Rabbit IgG #2729 using SimpleChIP ® Enzymatic Chromatin IP Kit (Magnetic Beads) #9003. The enriched DNA was quantified by real-time PCR using SimpleChIP ® Human c-Fos Promoter Primers #4663 and SimpleChIP ® Human α Satellite Repeat Primers #4486. The amount of immunoprecipitated DNA in each sample is represented as signal relative to the total amount of input chromatin, which is equivalent to one.