Phenotypic analysis of hematopoietic progenitor cells in heterozygous and FACKO mice. The bone marrow of wild type (+/+) and FACKO (−/−) mice (n = 5 animals per group) was analyzed for the presence of phenotypically defined HSC/progenitor cells. (A) Flow cytometric analysis of unfractionated marrow from wild type (a) and FACKO (b) mice. The percentage of lineage-negative cells is indicated (black dots). The frequency of lineage-negative cells after lineage depletion and incubation with antibodies to CD34 is shown in (c) and (d). The percentage of lineage-negative cells is shown (black dots). The expression of c-kit and Sca-1 on gated lineage-negative marrow cells is indicated in (e) and (f). The percentage of c-kit⁺, Sca-1⁺ cells is shown in the upper right quadrant, and the percentage of c-kit⁺, Sca-1⁻ cells is shown in the lower right quadrant. (B) The total number of phenotypically defined cells per femur in wild type (□) and FACKO (▪) mice is indicated on a log scale.