Figure 6.

Normal progenitor pools in NER-deficient Xpa^−/− mice. Hematopoietic progenitor cells were isolated from young (4 weeks) and old (56–58 weeks) wt (black bars) and Xpa^−/− (gray bars) mice and plated in CFU-G or CFU-GM (or in the case of young mice BFU-E) stimulating cytokine conditions. The colony numbers were counted on the 6th d of culture. The mean (±s.e.m.) of three cell pools (two mice per pool) is shown for the young mice and three individual animals for the aged mice. The only significant difference between wt and Xpa^−/− hematopoietic progenitor activity was detected in the aged mice and was restricted to the granulocyte–macrophage lineage (^*P<0.05).