Nuclei were purified after formaldehyde crosslinking, collected and resuspended in SDS Lysis buffer before sonication. Chromatin was sonicated to generate a majority of fragments between 200 and 600 bp. 10µg of each antibody was used per ChIP. Libraries for ChIP-Seq were prepared following Illumina protocols. The resulting libraries were sequenced on the Illumina HiSeq 2000 platform configured for 50bp single-end reads.