Figure 3.

Co-introduction of anti-DNA ligase IV antibody reduces DNA end-joining frequency in normal diploid fibroblasts but does not affect FA cells. (A) End-joining frequency of cohesive-ended DNA was determined in HT1080 cells (black bars) and normal HDFs (white bars) in the presence of no antibody (N), in the presence of anti-DNA ligase IV antibody (L), in the presence of anti-Fancd2 antibody (D), and in the presence of both anti-DNA ligase IV and anti-Fancd2 antibodies (L + D). In all cases, antibody treatment significantly reduced plasmid end-joining levels compared to those observed in cells not treated with antibody, P < 0.0001, χ²-test. (B) End-joining frequency of cohesive-ended DNA (black bars) and blunt-ended DNA (white bars) was determined in patient-derived FA-C cells in the absence of antibody (−) and in the presence of anti-DNA ligase IV antibody (+).