Association of RNA polymerase II, SRF, and ELK1 at the EGR1 promoter after a 2 h treatment with Tg plus PD98059. The locations of primers (labeled P1-P7) used to analyze the human EGR1 gene are illustrated relative to the transcription start site (arrow) and the two exons that comprise the protein-coding region of the gene are shown as black rectangles. The primer sequences are listed in Table 1. HepG2 cells were incubated in DMEM (Control) or DMEM + Tg for 2 h, both conditions also included 20 μM PD98059. The cells were then subjected to ChIP analysis with antibodies specific for RNA Pol II, total SRF, p-SRF, total ELK1, p-ELK1, and a non-specific IgG as a negative control. The data are plotted as the ratio to input DNA and are the averages ± SD for at least three samples within an experiment. The data shown are representative of multiple independent experiments.