Loss of Gli1 impairs in vitro granulopoiesis and differentiation of myeloid progenitors in vivo. (A) Whole bone marrow cells from Gli1^WT and Gli1^null mice were plated in methylcellulose supplemented with cytokines (Methocult M3434). Twenty thousand cells were plated per well, in duplicate. Results are mean ± SEM from 4 separate experiments. Colonies were scored at 12 to 14 days. *P < .05 (B) Photomicrograph of CFU-Gs grown in Methocult M3434. Original magnification ×40. (C) In vitro granulocyte formation measured by harvesting cells grown in Methocult M3434, labeling with antibody against Gr1, and analyzing by flow cytometry. Mature granulocytes were Gr1⁺ with high side-scatter properties. **P < .01 (D) Whole bone marrow was labeled with fluorescent-labeled antibodies and analyzed by flow cytometry for common myeloid progenitors (CMPs, FcRγ^lowCD34⁺cKit⁺Sca1^negLin^neg) and granulocyte macrophage progenitors (GMPs, FcRγ^hiCD34⁺cKit⁺Sca1^negLin^neg). Representative results from one pair of mice are shown. Percentages are of the c-Kit⁺Sca1^negLin^neg fraction. (E) Results for the myeloid progenitor subsets are summarized. Results are the mean percentage of total bone marrow cells ± SEM. *P < .05.