ChIP-seq were performed following the protocol: Using ChIP-seq technology to generate high-resolution profiles of histone modifications. O'Geen H, Echipare L, Farnham PJ. Methods Mol Biol. 2011;791:265-86. doi: 10.1007/978-1-61779-316-5_20. For ChIP-seq, sequencing libraries were prepared using the Illumina TruSeq DNA Sample Preparation Kit according to the manufacturer's protocol. After adapter ligation DNA was PCR amplified with Illumina primers for 15 cycles and library fragments of ~250-450 bp (insert plus adaptor) were band isolated from an agarose gel. DNA fragments were sequenced using single-end sequencing technology on Illumina HiSeq 3000 platform.