Hepatocytes were resuspended in resuspension buffer (10 mM Tris-HCl, pH 7.4, 10 mM NaCl, 3 mM MgCl2 and 0.1% Tween-20) supplemented with 0.1% NP-40 and 0.01% Digitonin. After incubation for 5 min on ice, 1 mL of resuspension buffer was added, and nuclei were pelleted at 600 × g for 5 min at 4℃. Nuclei were resuspended in transposition mix (10 mM Tris, pH 7.6, 5 mM MgCl2, 45 mM NaCl, 0.89 mM KCl, 2.7 mM Na2HPO4, 0.48 mM KH2PO4, 0.1% Tween-20, 0.01% Digitonin, 10% N,N-Dimethylformamide and 10% Illumina Tagment DNA TDE1 Enzyme (Illumina)) and incubated for 30 min at 37℃. Termination of the reaction and DNA purification was performed using MinElute Reaction Cleanup Kit (Qiagen). Libraries were amplified with barcoded primers using NEBNext High Fidelity 2 × PCR Master Mix (New England Biolabs). The PCR amplified products were cleaned with SPRIselect (Beckman Coulter).