For p300, we chemically crosslinked and sonicated cells to generate fractionated genomic DNA. Chromatin immunoprecipitation was performed by using anti-p300 (sc-585, Santa Cruz Biotechnology). The DNA fragments were blunt-end ligated to the Illumina adaptors, amplified, and sequenced by using the Illumina Genome Analyzer II (Illumina, San Diego, CA). Sequence reads of 25 or 36 bps were obtained by using the Illumina Analysis Pipeline. Publically available ChIP-seq datasets are listed in Table S1 and were obtained from several published studies 12 (link)-15 (link),26 (link)-29 (link).