Regulation of RAG locus conformation by GATA3, E2A, Runx1, and SATB1. (A) RAG locus map identifying sites analyzed by 3C. (B–E) 3C analysis of interactions of BglII fragments with the (B) ASE (left) and Rag1 promoter (right) viewpoints in wild-type and ASE mutant VL3-3M2 cells, (C) ASE (left) and Rag1 promoter (right) viewpoints in wild-type and Rag1 promoter mutant VL3-3M2 cells, (D) ASE viewpoint in wild-type or transcription factor KO VL3-3M2 cells, and (E) ASE (left) and Rag1 promoter (right) viewpoints in wild-type and Rag2 promoter–deleted VL3-3M2 cells. In each case the −104 fragment served as a negative control. The data represent the mean ± SEM of three to four independent experiments, with interaction frequencies normalized to those of a nearest neighbor BglII fragment. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 by two-way ANOVA with Holm-Sidak’s multiple comparisons test.