library_construction_protocol: The 1%(wt/vol) formaldehyde crosslinked, MNase digested and Qsonica sonicated chromatin fraction were incubated with indicated antibody overnight and Protein G magnetic beads (Thermo Fisher, 10004D) for another 3 h. After sufficient washing, elution and incubation at 65 °C overnight, DNA was purified through the DNA Extraction Reagent (phenol: chloroform: isoamyl alcohol (25: 24: 1) (pH8.0), Solarbio, P1012). DNA library was constructed by NEB DNA Library Prep Kit for Illumina (NEB, E7645S), according to the manufacturer's instructions.