Figure 3.

Altered CSR junctions in Fanca^−/− mice. (A) Splenic B cells from WT (n = 6) and Fanca^−/− (n = 6) mice were stimulated with anti-CD40 and IL-4, and 4 d later, Sμ–Sγ1 junctions were amplified by PCR from genomic DNA and then sequenced. Percentage of sequences with blunt joins (0), indicated MH, and junctional insertions (Ins) are shown. Data from six independent experiments were pooled and analyzed by the χ² test (**, P < 10⁻³). (B) A plot representing the relative frequency of sequences with blunt joins, MH, or insertions for WT and Fanca^−/− B cells from A. (C) A schematic representation of the I-SceI chromosomal reporter. (D) The GCV6 cells containing the I-SceI substrate described in C were transfected with siCT or siFANCA for 48 h and subsequently with I-SceI–expressing plasmid. 3 d later, I-SceI junctions were amplified from genomic DNA and then sequenced. Percentage of sequences with blunt joins (0), indicated MH, or insertions at the I-SceI–induced NHEJ junction are reported. Analyzed sequences were obtained from two independent experiments (*, P < 10⁻²).