For all ChIPs except EZH2, cells were crosslinked in 0.6% formaldehyde. For Ezh2 ChIPs, cells were crosslinked in 1.5mM EGS (ethylene glycol bis(succinimidyl succinate); ThermoFisher Pierce) in PBS for 30 minutes and then in 0.6% formaldehyde. Whole cell lysates were sonicated and chromatin extracts were immunoprecipitated using the specified antibody. Purified immunoprecipitated DNA was prepared for sequencing on the Illumina platform using Next Reagents (NEB).