Cells were fixed in 1% formaldehyde. Pellet was resuspended in complete sonication buffer (20mM Tris pH 8.0, 2mM EDTA, 0.5mM EGTA, 1x protease inhibitors (Roche), 0.5% SDS and 0.5mM PMSF) in 1mL for 1x108 cells DNA libraries were prepared using ThruPlex Kit