Chromatin was sheared into fragments with an average size of 300-500 bp using a Covaris S220. Sequencing libraries were prepared from ChIP DNA using KAPA Library Amplification Kit (KAPA Biosystem). Briefly, ChIP DNA was end-repaired, A-tailed, ligated to the adapters, size selected to 200-500 bp and amplified by PCR. Libraries were sequenced on the HiSeq 1500 (Illumina) as single-end 50-bp reads.