Cytokine-mediated inhibition of

Fancc^−/− BM colony formation is blocked by the addition of L-NMMA. (A) Hematopoietic colony formation by Fancc^−/− (■) and littermate wild-type (♦) BM progenitor cells plated in methylcellulose in the presence of increasing concentrations of IFNγ. (B) Colony formation by BM cells from wild-type (♦) and Fancc^−/−(■) mice grown in the presence of IFNγ (1 ng/mL) and increasing concentrations of L-NMMA. Data points represent the average number of colonies counted. n = 3 mice per genotype. *P < .05; **P < .005.