Recovery of FANCD2 monoubiquitination in the FA-I F010191 fibroblasts. (A) HeLa and F010191 fibroblasts were either untreated or treated with HU (2mM for 18 hours). (B-C) F010191 fibroblasts were transfected with empty vector or the indicated FANCI expression constructs. Forty-eight hours after transfection, cells were treated with 2mM HU for 24 hours and FANCD2 monoubiquitination was assessed by Western blot analysis and probed with the indicated antibodies. The L/S ratio was calculated as described in Figure 3A.