Hoxa9 and Hoxa10 are essential for the proliferation of Setbp1-immortalized myeloid progenitors. (A) Top panel, mean and SD of colony formation potential of BM70 cells in the presence of SCF and IL-3 at 48 hours after infection with Hoxa9-specific shRNAs (Hoxa9-sh1 and Hoxa9-sh2) and control shRNA (NC-sh); bottom panel, representative Western blotting analysis of Hoxa9 and actin protein in the infected cells of the top panel at 72 hours after infection. Relative Hoxa9 protein levels after normalization to actin levels in the same sample are indicated. (B) Mean and SD of colony formation potential in the presence of SCF and IL-3 (top panel) and Western blotting analyses (bottom panel) of BM70 cells at 48 and 72 hours, respectively, after infection with Hoxa10-specific shRNAs (Hoxa10-sh1 and Hoxa10-sh2) and control shRNA (NC-sh). Relative Hoxa10 protein levels after normalization to actin levels are indicated. (C) Cell cycle distribution of BM70 cells infected with Hoxa9-sh1 and Hoxa10-sh2 and control shRNA determined by PI-staining at 72 hours after infection. The mean and SD of each phase is shown (*P < .05).