Genomic DNA was isolated using KIT (TIANGEN) according to the manufacturer's instructions. The ChIP-Seq library preparation was proceeded as follows: (1) The DNA fragments were end-repaired and A-tailed. (2) The DNA fragments with A tail were ligated with sequencing adaptors. (3) The final DNA library was obtained after size selection and PCR amplification. Libraries were analyzed for size distribution by Agilent 5400 system（Agilent, USA）and quantified by QPCR (1.5 nM). The qualified libraries were pooled and sequenced on Illumina platforms with PE150, according to the effective library concentration and data amount required.