Cell-cycle alterations in steady-state BM of Dmtf1^−/− mice. (A) Cell-cycle analysis in steady-state BM was performed with DAPI. Percentages of cycling cells (S/G₂/M) are shown for each fraction (n = 4). *P < .05. (B) Cell-cycle status of KSL cells was evaluated with Hst/Py staining. WT or Dmtf1^−/− BM low-density cells were stained for surface antigens followed by Hst/Py staining. Dot plots in panel B show representative results of Hst/Py staining of WT and KO cells depicting G₀ (bottom left quadrant), G₁ (top left quadrant), and S/G₂/M (top right quadrant) in KSL cells. Bar graph to the right shows the percentage of cells in the 3 phases of cell-cycle as average ± SD. *P < .03. (C) Lin⁻ cells from WT and Dmtf1^−/− mice were cultured without cytokines in serum-supplemented medium for the indicated times and stained with annexin V/propidium iodide (PI). Data shown are the mean percentage ± SD of annexin V⁺/PI⁻ and annexin V⁺/PI⁺ cells. No significant differences were observed between WT and Dmtf1^−/− mice (n = 3).