Chromatin immunoprecipitation (ChIP) was performed using formaldehyde crosslinked chromatin sonicated to an average size of 200-600 bp and the indicated antibodies. 5-10 ng of DNA was processed using NEBNext and Illumina ChIP seq kits according to the manufacturer's instructions. In brief, DNA was adaptor-ligated, subjected to gel size selection, amplified and analyzed by Solexa/Illumina high-throughput sequencing.