Figure 4.

The cellular phenotype of human UBE2T−/− fibroblasts is comparable to that of FA cells with defects in FA core complex members. (A) Survival of UBE2T−/− fibroblasts after exposure to genotoxins. An isogenic pair of UBE2T−/− fibroblasts transduced with a retroviral vector encoding UBE2T or the corresponding control vector were exposed to increasing doses of the genotoxins cisplatin, ionizing radiation and camptothecin. (B) Western blot analysis to visualize intact FANCD2 and FANCI monoubiquitination in immortalized UBE2T−/− fibroblasts after exposure to MMC by UBE2T expression. (C) Restoration of FANCD2 recruitment to sites of DNA crosslinks by UBE2T expression. Psoralen interstrand crosslinks were induced along the track of a UVA laser in corrected and non-corrected UBE2T−/− fibroblasts and then visualized by γ-H2AX staining. FANCD2 accumulation at the sites of psoralen laser tracks only occurred in FA100166/1 cells that had been transduced with the UBE2T expressing retroviral vector.