Complementation of FA group C cells with FAC molecules. Trypan blue exclusion was used to assess cellular viability of HSC536 lymphoblasts incubated in the presence of MMC continuously for 5 days. HSC536-FAC, HSC536 lymphoblasts stably transfected with wild-type FAC. Treatments with exogenous protein included His-ILFAC (1 μg/mL), His-FAC (1 μg/mL), and recombinant human IL-3 (1 μg/mL) added to the culture medium of HSC536 cells daily for 5 days. Each experiment was performed in triplicate. The mean and standard error of the mean are shown.