For histone marks, 6 x 10^6 cells were harvested, and for ATFs, 2.5 x 10^7 cells were harvested. Cells were fixed in 1.5% formaldehyde, then flash frozen. Cells were lysed with a series of 3 buffers: LB1, LB2, and LB3. LB1 consisted of 10 mM HEPES, 10 mM EDTA, 0.5 mM EGTA, and 0.25% Triton X-100. LB2 consisted of 200 mM NaCl, 10 mM HEPES, 1 mM EDTA, and 0.5 mM EGTA. LB3 consisted of 50 mM Tris-HCl, 10 mM EDTA, 0.5% Empigen BB, and 1% SDS. Samples were sonicated in a Misonix sonicator (S-4000) at 60% power, 10 sec on and 10 off, for a total of 32 min total pulse time. Samples were cleared by centrifugation 17,000 x g for 10 min. For preclearing, samples were incubated with magnetic Protein G beads (Life Technologies #10003D) for 1 hour at 4°C. After preclearing, 1% of sample was saved as input. Samples were incubated with the appropriate antibody, H3K27ac antibody (Abcam #ab4729), H3K9me3 antibody (Abcam #ab8898), or HA antibody (Abcam #ab9110), overnight at 4°C with IP Buffer (2 mM EDTA, 150 mM NaCl, 20 mM Tris-HCl, and 1% Triton X-100). Protein-DNA complexes on magnetic beads were washed in WB1 once, WB2, once, WB3 once, and TE Buffer twice. WB1 consisted of 2 mM EDTA, 20 mM Tris-HCl, 0.1% SDS, 1% Triton X-100, 150 mM NaCl). WB2 consisted of 2 mM EDTA, 20 mM Tris-HCl, 0.1% SDS, 1% Triton X-100, and 500 mM NaCl. WB3 consisted of 1 mM EDTA, 10 mM Tris-HCl, 250 mM LiCl, 1% deoxycholate, and 1% NP-40. DNA was eluted in 0.1 M NaHCO3, 0.2 M NaCl, and 1% SDS. Protein-DNA complexes were reverse crosslinked by incubation at 65°C for 6 hours. DNA was treated with RNase A and Proteinase K. Captured DNA was column purified (Epoch Life Sciences #1920-250). Samples were prepared for sequencing with the TruSeq ChIP Sample Preparation Kit (Illumina #IP-202-1012) as per the manufacturer instructions and quantified with a Qubit fluorometer (Life Technologies #Q32866). Three, four or six TruSeq indexed ChIP samples were pooled per lane. All samples were loaded at a final concentration of 8 pM and sequenced as single reads on the Illumina HiSeq 2500 following the manufacturer's protocols.