a, Genome browser view of the Igκ locus indicating the location of the Vκ gene segments and deposition of H3K27Ac (GSM3103098) and H3K4me1 (GSM2084579) in WT-Rag1−/−.hIgM pre-B cells. Blue and green highlights indicate a potential enhancer in the vicinity of the Igkv7–33 gene and the IgκRR, respectively. b, Genomic region spanning the Igkv7–33 gene is shown. CTCF (GSM2973687) occupancy and deposition of H3K27Ac and H3K4me1 (upper panel) are shown. Lower tracks show enrichment for the deposition of H3K27Ac and H3K4me1. E2A (GSM546523), EBF (GSM1296532), IRF4 (GSM1296534), PU.1 (GSM1296533), and Pax5 (GSM932924) occupancy across the Igkv7–33 genomic region is indicated. Bottom indicates genomic position of gRNAs used to excise the E34 enhancer. c, p300 (GSM987808), Brg1 (GSM1635413), and Mediator (GSM1038263) occupancy across a genomic region spanning the E34 enhancer. d, Genotyping of DNA derived from wild-type (WT) cells and cells carrying the E34-targeted deletion is shown. Indicated are representatives from two independent experiments.