Cell lysates were clarified from sonicated nuclei and histone-DNA complexes were isolated with antibody. Libraries were prepared using Illumina TruSeq ChIP Sample Prep kit following manufacture's protocol. Briefly, ChIP DNA was end-repaired, 3'-adenylated, and then ligated with indexed adaptor. These DNA was size selected (200-400 bp) via agarose gel electrophoresis, and PCR amplified. Final products were purified using AMPure XP beads.