5 million cells were crosslinked in 1% formaldehyde for 10 minutes, lysed, sonicated to ~500bp, and immunoprecipated using H3K27ac antibody (Active Motif 39133). In the case of tissue, 5-10mg of tissue was pulvarized in liquid nitrogen before cross-linking in the same manner as cell protocols (above) ChIP DNA was purified using the Qiagen PCR purification kit. Libraries were prepared according to manufacturers instructions using the Rubicon Thruplex DNA-seq kit Libraries were constructed using the DNA-seq kit from Rubicon Genomics and quantified using Picogreen