Figure 3.

Class switch recombination (CSR) in murine and human activation-induced deaminase (AID)-deficient samples. (A) Sµ-Sγ murine CSR junctions were PCR-amplified and sequenced from spleen B-cells at 17 days after sheep red blood cell immunization, comparing mutant and control mice (top). Sµ-Sγ human CSR junctions were also PCR-amplified and sequenced from blood and tonsils from AID-deficient human samples (bottom). Numbers of independent reads including Sµ–Sγ junctions are shown on the left graph. Independent reads including the same CSR breakpoint were assembled and considered as clusters; numbers of independent clusters are shown on the right graph. Junction structures were analyzed using CSReport. (B) Structures of repaired junctions were analyzed depending on the mean number of inserted nucleotides and length of microhomologies between the broken ends of Sμ-Sγ junctions in WT and AID-deficient samples. χ ² test was used for significance of IgG CSR structure analysis. **p < 0.01; ***p < 0.001; ****p < 0.0001.