Cbfb-MYH11 expression results in an abnormal Csf2rb⁺ population with reduced progenitor activity. Representative FACS plots of c-Kit and ScaI (A), and Csf2rb (B) staining in lineage-depleted (lin⁻) bone marrow from mice of Cbfb^+/56/M, Mx1-Cre⁺ and Cbfb^+/+ mice at the indicated number of days after treatment with pI:pC. Percentage of cells in each gate is given. N ≥ 3 for all genotypes. (C) Representative FACS plots of c-Kit and ScaI staining of the Csf2rb⁻ and Csf2rb⁺ populations from lin⁻ bone marrow from Cbfb^+/56M, Mx1-Cre⁺ mice 10 days after Cbfb-MYH11 induction. (D) Bar graphs of the relative total numbers of colonies seen from lin⁻ bone marrow cells from Cbfb^+/56M, Mx1-Cre⁺ mice 10 days after induction of Cbfb-MYH11 expression, sorted for Csf2rb expression and grown in culture for 12 days. N ≥ 3. *Statistically significant difference (P < .01). (E) FACS staining for Csf2rb of colonies derived from the Csf2rb⁻ cells described in panel C. Percentage of Csf2rb⁺ cells is indicated. Error bars indicate SD within the indicated cell population.