The FANCD2 CUE mutants fail to rescue the MMC-hypersensitivity of FA-D2 patient cells. (A) FA-D2 cells reconstituted with WT or mutant FANCD2 were treated with the indicated concentrations of mitomycin C (MMC) for 7 to 10 days. Cells were fixed and stained with crystal violet and percent survival calculated and plotted. Each measurement was performed in triplicate. The averages for 3 independent experiments were calculated and plotted. (B) FA-D2 cells reconstituted with WT or mutant FANCD2 were incubated in the absence or presence of 8 or 16nM MMC for 24 hours and the numbers of chromosome aberrations including gaps and breaks, dicentrics, and complex chromosome aberrations, including radial formations, were scored. Metaphase spreads were analyzed using a Zeiss AxioImager.A1 upright epifluorescent microscope with AxioVision LE 4.6 image acquisition software. At least 80 metaphases were scored per treatment. Error bars represent the standard error of the mean.