Cells were fixed with 1% formaldehyde at RT for 10 min, and the fixation was stopped by 125 mM glycine at RT for 5 min. The chromatin pellets were extracted from cells by lysis buffer (10 mM Tris-HCl pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.5% NP-40), and resuspended with 0.8 ml of RIPA buffer. 10ng DNA was used as starting material for input and ip samples.After the DNA samples quality control，the purified DNA was used NEBNext Ultra II DNA Library Prep Kit （NEB, USA, Catalog #: E7645L）for ChIP-seq library preparation.