Analysis of multipotent and committed hematopoietic progenitors in mTerc^−/− BM cells from different generations and genetic backgrounds.

(A) BM cells were analyzed for CFU-GM, pre-B CFU, CFU-Mk, HPP-CFC, and CFU-S₁₂ content as described in “Materials and methods.” (B) The replating ability of CFU-S₁₂ and CFU-GMs was analyzed. Individual CFU-S₁₂ spleen colonies generated in irradiated mice were dissected, dispersed, and injected into secondary irradiated recipients and assayed for secondary CFU-S₁₂; CFU-GM colonies were isolated, replated in methylcellulose cultures, and assayed for secondary CFU-GMs. Results are shown independently; the statistical significance of differences between mean values (■) was determined by means of the 2-tailed Student t test.