ChIP was carried out as previously described (Weber et al., 2007) with slight modifications. Changes to the protocol were following; (1) chromatin was sonicated for ~50 cycles of 30 sec. using a Diagenode Bioruptor, with 45 sec. breaks in between cycles, (2) protein A/G magnetic Dynabeads Magnetic beads (Thermo Fisher Scientific) were used, (3) DNA was purified using on-column purification instead of chloroform/phenol extraction (Qiagen PCR Purification Kit). Immunoprecipitated DNA and input DNA were submitted to library preparation (NEBNext Ultra DNA Library Prep Kit, Illumina). In the library preparation protocol, input sample were amplified using 4 PCR cycles, IP sample using 12 cycles.