16-hours after transfection, cells were fixated using paraformaldehyde, lysated and nuclei were prepared and sonicated. ChIP was performed with an in-house antiZac1 antibody. The protocol described by Kouskouti & Kyrmizi (http://www.epigenome-noe.net/WWW/researchtools/protocol.php?protid=10) was used. Libraries were prepared according to Illumina's instructions using the ChIPseq DNA sample prep kit (IP-102-1001). For each sample, 10ng of DNA was repaired, resulting in blunt end fragments and adenylated on its 3' ends. Illumina's adapters were ligated on adenylated DNA. A sizing step was performed on an agarose gel (fragment size including adapters: 200bp) followed by a 18 cycles PCR to amplify fragments with both adapters. Libraries were validated on a DNA1000 Chip on a Bioanalyzer (Agilent).