10 ng of ChIP DNA was end polished with T4 DNA polymerase and kinase. An 'A' base was added to the polished DNA fragments, followed by the Qiaquick column clean up. Solexa adaptors were ligated to the ChIP DNA fragments and enriched by 15 cycles of PCR amplification. 200-300 bp size fractions were selectively isolated from the 1% agarose gel and eluted by the Qiagen gel extraction kit. The extracted DNA was quantified by picogreen assay and subjected to HiSeq2000 sequencing according to the manufacturer's instructions. DNA libraries were prepared for sequencing using standard Illumina protocols