Distribution of myeloid progenitor populations of transplanted BM cells at the early stage. BM cells were isolated from mice preinjected with 5-FU 5 days before, and infected with retroviral vectors containing control GFP (MigR1), COP1, and Trib1. Six to 8 weeks after BMT, mice were killed, and BM cells were analyzed by fluorescence-activated cell sorter. (A) The level of GFP signals in BM cells is shown in the upper panels (the percentage of GFP-positive cells). GFP-negative (GFP⁻, middle panels) and -positive (GFP⁺, lower panels) BM cells were stained with anti-Mac1 and anti–Gr-1 antibodies. The percentages of immature (Mac-1⁺Gr-1^lo) and differentiated (Mac-1⁺Gr-1^hi) granulocytes are shown. (B) GFP-positive BM cells were stained with a lineage cocktail without anti–Mac-1 and anti–Gr-1 (Lin*, upper panels), and the Lin*^negSca-1⁻ population was stained with anti–c-Kit and anti–Mac-1 (lower panels). The percentages of fractions containing CMP/GMP/MEP (Lin*^negSca-1⁻Mac1⁻c-Kit⁺), committed myeloid progenitors (Lin*^negSca-1⁻Mac1⁺c-Kit⁺), and differentiated myeloid cells (Lin*^negSca-1⁻Mac1⁺c-Kit^lo/−) are shown. Results are representative of 4 independent experiments.