Cells were fixed with 2mM DSG for 30 min followed by 1% formaldehyde for 10 min and treated with 0.125M Glycine for 5 min. Washed cells were suspended in ChIP Lysis Buffer and shredded using Bioruptor (Diagenode) or E220 Focused-ultrasonicator (Covaris). Histone-DNA complexes were isolated with antibody. ChIP-seq libraries were constructed with the ThruPLEX DNA-seq Kit following the manufacturer's recommended protocol (Rubicon genomics).