library_construction_protocol: Cells were fixed in 1% formaldehyde for 15min with rotation then quenched with 0.125M glycine. After cell membrane lysis and then nuclear lysis, chromatin was sonicated using a Vocariss E220 sonicator (140W, 10% duty, 200 cycles/burst, 600sec/sample). NEBNext Ultra II DNA library prep kit with NEBNext multiplex oligos; 6 cycles of amplification