For ChIP-seq, samples were fixed for 10 minutes with 1% formaldehyde. Fixation was stopped by adding Glycine (0.125M). Chromatin DNA was sheared to 200–500 bp size by sonication. Soluble sheared chromatin was immunoprecipitated with specific antibodies overnight at 4°C. Next day, lysates were incubated in prewashed protein G dynabeads (Invitrogen). After washing and elution, the protein–DNA complex was decross-linked by heating at 65°C for 4 hours. Immunoprecipitated DNA was purified by using QIAquick PCR purificaion kit. The libraries were constructed following Illumina’s Chip-Seq Sample prep kit.