ChIP were performed as described in Gevry N, Chan HM, Laflamme L, Livingston DM, Gaudreau L. p21 transcription is regulated by differential localization of histone H2A.Z. Genes & development. 2007;21(15):1869-81. PubMed PMID: 17671089 except for the following steps. For each treatment conditions six immuno-precipitations were performed. Immuno-precipitations were performed using Dynabeads coupled to protein A (Life Technologies) without pre-clearing. The libraries for deep-sequencing were prepared from 10 ng ChIPed DNA using the NEBNext Ultra DNA Library Prep Kit for Illumina (NEB) according to manufacturer’s protocol