Impaired neutrophil development in Mcl-1–deficient mice. (A) FACS profiles of blood, spleen, and BM of Mcl-1^−/− and control mice. Single-cell suspensions were stained with FITC–anti–Mac-1 and APC–anti–Gr-1 monoclonal antibodies. Shown are cells gated on granulocytes based on their forward and side scatter. Numbers indicate the percentage of cells in the gated regions. Data are representative of 3 independent experiments from a group of 9 mice. (B) Percents of lymphocytes, PMN cells, and monocytes in the blood of Mcl-1^−/− and control mice. Blood smears were stained with Hema 3 and counted under light microscopy; n = 6 for each group. Data are mean + standard deviation. (C) Expression of Mcl-1 in purified BM neutrophils from Mcl-1^−/− and control mice as determined by Western blot. Erk2 serves as a loading control. Data are representative of 2 experiments.