Cells were crosslinked with 1% formaldehyde for 10 min at 37◦C; then, crude nuclei were purified. Chromatin was fragmented by sonication with a Bioruptor UCD-300 (Diagenode) to obtain fragments 200–800 bp in length. For each ChIP assay, 2–5 ug of antibodies were added and incubated at 4◦C overnight. ChIP DNA was quantified with a Qubit fluorometer using the Quant-iT dsDNA HS assay kit ChIP-seq libraries were generated following the procedue described in "TELP, a sensitive and versatile library construction method for next-generation sequencing" by Peng X, Wu J, Brunmeir R, Kim SY, Zhang Q, Ding C, Han W, Xie W, Xu F., published in Nucleic Acids Res. 2015 Mar 31;43(6):e35. doi: 10.1093/nar/gku818. Epub 2014 Sep 15.