FIG 1.

V(D)J recombination in mutant mice. (A) The schematic at the top shows the mouse IgH locus (not to scale). CBEs, CTCF-binding elements. Not all CBEs are shown. Genomic DNAs were prepared from sorted WT and Δ3′RR pro-B cells and subjected to qPCR to amplify unrearranged D_Q52 and J_H1 gene segments. The relative positions of the primers are indicated in the schematic above the graph. Genomic DNA from Rag2^−/− mice was used as a control. The hs5 sequence was used for normalization (n = 4). (B) Genomic DNAs from sorted pro-B cells and double-positive thymocytes were subjected to qPCR to quantify D-J_H1, D-J_H2, D-J_H3, and D-J_H4 recombination events. Rag2^−/− and kidney DNAs were used as negative controls (n ≥ 4). (C) Quantification of distal (dV_H) V_H-DJ_H recombination events in pro-B cells by qPCR (n ≥ 4). **, P < 0.01; *, P < 0.05; ns, not significant. Error bars indicate SEM.