This region spans multiple DNase I hypersensitive sites and includes the promoter region of the paired box 5 (Pax5) gene. Early B-cell factor 1 and signal transducer and activator of transcription 5 bind to this sequence and synergize to promote activity of this promoter. Four subregions were identified as putative B cell regulatory elements by FAIRE-seq (formaldehyde-assisted isolation of regulatory elements sequencing), and were validated as enhancers by STARR-seq (self-transcribing active regulatory region sequencing) in lipopolysaccharide-activated mouse splenic B cells. Two of those enhancers were additionally validated by standard reporter assays in CH12 B lymphoma cells. [provided by RefSeq, Oct 2023]