Cells were processed for ChIP as previously described with slight modifications (Dietrich, Lerdrup et al., 2012). Briefly, cells were fixed for 10 min in culture media containing 1% formaldehyde and were processed for ChIP as previously described with slight modifications (Dietrich et al., 2012). ChIP DNA from three parallel ChIPs were pooled or individual ChIPs from three biological replicates were used and 10 ng each was used for making ChIP-seq libraries. The libraries were prepared using “ChIP seq DNA sample preparation kit” from Illumina following manufacturer's instructions. H3K27ac samples were multiplexed (using NEB kit) and run on HiSeq2000 (Illumina).