Colony-forming assays.

(A) Colony-forming assays reveal decreased numbers of progenitors inFancc^−/−Sod1^−/−BM samples. Myeloid (dark bars) and pre-B (hatched bars) CFUs were determined forSod1^−/−, Fancc^−/−, Fancc^+/+ Sod1^+/+, Fancc^+/−Sod1^+/−, andFancc^−/−Sod1^−/−mice. The decrease in the number of progenitors/femur is highly significant (P = .0002) whenFancc^−/−Sod1^−/−mice are compared to Fancc^+/+Sod1^+/+controls. Values represent the average number of progenitors/femur of 6 mice per group ± SEM. * = P < .05, ** = P < .001. (B)Fancc^−/−Sod1^−/−progenitors fail to generate normal ratios of CFU-GEMM, CFU-GM/G/M, and BFU-E. Myeloid colonies from panel A were assessed morphologically to determine the cell types contributing to the colonies. CFU-GEMM (dark bars), CFU-GM/G/M (light gray bars), and BFU-E (hatched bars) colonies were scored by eye and the values represent average percent of cell type ± SEM (n = 6-8 mice/group). Ratios of CFU-GM/G/M, and CFU-GEMM from Fancc^−/−Sod1^−/−samples were significantly different fromFancc^+/+Sod1^+/+ controls (P = .002 and P = .003, respectively).