For ChIP-seq, VCaP cells were silenced using siRNA transfection for three days when indicate, grown on steroid-depleted medium for two days and treated for 1h with R1881 (10mM) or equal volume of vehicle (ethanol). Samples were fixed for 10 min. in room temperature with 1% (v/v) formaldehyde, fragmented to 200-400bp fragments by sonication (Bioruptor, Diagenode) and chromatin immunoprecipitation was done using rabbit polyclonal anti-BCOR antibody (A310-672A, Bethyl Laboratories), rabbit antiserum against AR or anti-H2AK119ub antibody (#8240, Cell Signaling Technology). Two biological replicates of each condition were sequenced using Illumina HiSeq 2000 or NextSeq500 at EMBL GeneCore (Heidelberg, Germany). Library preparation was done using NEBNext Ultra II kit (New England Biolabs) and sequenced using Illumina HiSeq 2000 or NextSeq 500 at EMBL GeneCore (Heidelberg, Germany).