Cells were scraped off dishes and collected by centrifuge. Cross-linked chromatin complexes were isolated from the Nuclei lysis buffer and then sonicated to obtain fragments in a size range between 350-500bp. H3R26Cit antibody (ab19847) were incubated with solubilized DNA fragments overnight at 4°C. Protein A/G agarose beads (Pierce, Rockford, IL) were used to capture the antibody-chromatin complex followed by washes and elution with 1% SDS. The DNA was recovered by reversing the cross-links with 20 mM NaCl at 65°C overnight. DNA was purified by QIAquick PCR Purification Kit (Qiagen 28106) and dissolving in a final volume of 30ul per immunoprecipitation. The Protocol of KAPA High-Throughput Library Preparation Kit (Cat. No. KK8234)