FAIRE experiments were performed as described (Giresi PG et al. Methods 2009;48(3):233-9): fresh frozen tissues were crosslinked with 1% formaldehyde for 20 min. Cells were washed, nuclei isolated. Chromatin was sonicated and cleared by centrifugation. The soluble chromatin was subjected to three consecutive phenol-chloroform-isoamyl alcohol (25:24:1) extractions. The samples were reverse crosslinked overnight at 65°C and purified by ethanol precipitation. Purified samples were treated with RNase A and proteinase K and repurified by PCR purification kit. Chromatin Immunoprecipitation was performed as described (Zwart W et al. BMC Genomics 2013;14:232): 10mg (ChIP-seq) or 5mg (ChIP-QPCR) of antibody was used, with 100ml (ChIP-seq) of Protein A magnetic beads. Antibody used was AR-N20 (sc-618; Santa Cruz). DNA was amplified as described (Ross-Innes CS et al. Nature 2012;481(7381):389-93). Libraries were prepared according to Illumina's instructions accompanying the DNA Sample Kit (Part# 0801-0303).