Integrations are highly enriched at enhancers. Integration-enrichment analyses of promoter-distal integration sites with enhancers from thymus, spleen and brain including also the insulator CTCF and promoter marker H3K4Me3. The number associated with each bar indicates the absolute number of integrations that colocalized with a given ChIP-seq marker. We defined direct colocalization based on extension of ChIP-seq peaks by 1,250 bp (described in Methods). The enrichments shown were highly significant compared to random (P < 0.001). The lower panel shows the percentage of the genome that the ChIP-seq features comprise including sequence extensions up to 5,000 bp.