A role for the Ddb1–Cul4Cdt2 ubiquitin ligase complex in gap filling of break-induced resected ssDNA. (A) Fivefold serial dilutions of wild-type, exo1Δ, ku70Δ, ddb1Δ, ddb1Δku70Δ, ddb1Δku70Δspd1Δ, ddb1Δexo1Δ, and ddb1Δku70Δexo1Δ strains grown on Ye5S and Ye5S + 0.0025% bleomycin. (B) Bleomycin survival curve for wild-type, ddb1Δ, ddb1Δku70Δ, ddb1Δexo1Δ, and ddb1Δku70Δexo1Δ strains exposed to the indicated doses of bleomycin for 1 h. Means ± standard errors of three experiments are shown. (C) Quantification of Rpa1(Rad11)-GFP foci in wild-type, ddb1Δ, and ddb1Δspd1Δ strains following exposure to 50 Gy of IR treatment. (D) Quantification of Rhp51-CFP foci in wild-type, ddb1Δ, and cdt2Δ strains following exposure to 50 Gy of IR.