Lysates from sonicated nuclei were prepared and protein-DNA complexes were IP'd overnight with BRD4 antibody. ChIP-seq libraries were prepared according to Illumina's ChIP Truseq protocol. Briefly, ChIP DNA was end-repaired and adaptors were ligated to the ends of the DNA fragments. Adaptor-ligated ChIP DNA fragments with average size of 350 bp were used to construct libraries and single-end sequenced on Illumina HiSeq 4000.