Figure 4.

Elevated Levels of DNA Damage in RAD51-Deficient Human Cells Treated with PDS

(A) Representative images of HEK293T cells transfected with control or RAD51 siRNA and treated with PDS for 4 days before processing for immunofluorescence staining with anti-γH2AX antibody (green). DNA was counterstained with DAPI (blue).

(B) Quantification of the frequency of cells with ≥5 γH2AX foci treated as in (A); n = 3; error bars, SD. p values were calculated using an unpaired two-tailed t test (^∗p ≤ 0.05; ^∗∗p ≤ 0.01).

(C) Representative images of cells treated as in (A) processed for comet assays. Scale bar, 50 μm.

(D) Quantification of tail moment using comet assays of cells treated as in (A); n = 3; error bars, SD. p values were calculated using an unpaired two-tailed t test (^∗p ≤ 0.05).

(E) Representative images of FISH analysis of metaphase chromosome spreads of cells treated as in (A) with a Cy3-conjugated telomeric probe (red). DNA was counterstained with DAPI (blue). Arrowheads point to chromatid/chromosome breaks.

(F) Quantification of mean DSB frequencies (red bars) in cells treated as in (A). Approximately 40 metaphases were analyzed for each sample. See also Figure S3.