Sonicated soluble chromatin was immunoprecipitated with 15 mg of H3K27ac antibody and pulled down by protein G sepharose beads equillibriated with yeast tRNA and BSA. Purified DNA (10 ng) was end-repaired and A-nucleotide overhangs were added by incubation with the Taq Klenow fragment lacking exonuclease activity. After the attachment of anchor sequences, fragments were PCR-amplified using Illumina-supplied primers. The purified DNA library products were evaluated using Bioanalyzer (Agilent).