Analysis of Hmgb3 expression in myeloid progenitors (MP). (A) Isolation of myeloid progenitors by flow cytometry. Upper: Lin^– bone marrow isolated from Hmgb3-KI mice. Middle: c-kit and Sca-1/IL-7Rα expression in Hmgb3-KI Lin^– bone marrow. Cells positive for c-kit and negative for Sca-1/IL-7Rα were selected based on isotype controls (not shown). Lower: c-kit⁺/Sca-1 and IL-7Rα^– cells were stained with either anti-FcγRII/III or CD34 monoclonal antibodies as described in “Materials and methods.” Left: FcγRII/III and GFP expression in Hmgb3-KI Lin^– c-kit⁺/(Sca-1/IL-7Rα)^– cells. Right: CD34 and GFP expression in Hmgb3-KI Lin^– c-kit⁺/(Sca-1/IL-7Rα)^– cells. Sort gates were drawn based on isotype controls (not shown). (B) Mean CFU-GM, BFU-E, and CFU-GEMM frequency in FcγRII/III^LO GFP^– (n = 6) and GFP⁺ (n = 6) MP populations. Values were determined by scoring CFU-GM, BFU-E, and CFU-GEMM colonies per 500 cells cultured. P values were determined by Student t test. (C) Mean CFU-GM, BFU-E, and CFU-GEMM frequency in CD34⁺ GFP^– (n = 5) and GFP⁺ (n = 4) MP populations. Values were determined by scoring CFU-GM, BFU-E, and CFU-GEMM colonies per 500 cells cultured. P values were determined by Student t test.