The ChIP-seq has been carried out as previously described6,7. Briefly, 2 million cells were crosslinked with 1% formadehyde for 10 min at RT. The reaction was quenched by adding 125 mM of Glycine and incubating for 5 min at RT. Cells were lysed in RIPA buffer (10 mM Tris-HCl pH 8.0, 140 mM NaCl, 1 mM EDTA, 1% Triton X-100, 0.1% SDS, 0.1% sodium deoxycholate) supplemented with protease inhibitor (Roche). And chromatin was sonicated into short fragments (300-700 bp). The fragmented chromatin was incubated with antibodies to pull down the specific DNA bound TFs or histones. After intensive wash, DNA was purified and prepared as sequencing library using illumina Truseq LT kit. TruSeq