M33-Meis1 imposes a partial G1-phase cell-cycle block on ND13- and Hoxa9-transduced BM cells. (A) Primary BM cotransduced with ND13pac and MIY, Meis1, or M33-Meis1 were incubated with Hoechst and Pyronin and analyzed by FACS analysis. Cell-cycle profiles of untransduced (YFP−) and transduced (YFP+) are shown for each experimental condition. Numbers denote the percentage of cells within the quadrant. (B) Cell-cycle profiles of primary BM cotransduced with Hoxa9neo and MIY, Meis1, or M33-Meis1. Data in the bar graphs are expressed as the mean ± SD of 3 independent transductions. Numbers denote the percentage of cells within the quadrant.