The hematopoietic defect in Aurka^−/− mice is cell autonomous. (A) In noncompetitive transplant experiments, mice engrafted with Aurka^fl/fl/Mx1-Cre (Aurka^−/−) bone marrow died within 21 days of pI-pC treatment. (B) Complete blood counts from mice transplanted with Aurka^fl/fl/Mx1-Cre (Aurka^−/−) and Aurka^+/+/MX1-Cre (WT) bone marrow 17 days after pI-pC treatment. Data are shown as mean ± SD. (C) H&E-stained sections of sternum bone marrow from WT and Aurka^−/− mice. Images were acquired as described in Figure 1F. (D) CD45.1 and CD45.2 stained bone marrow cells from representative Aurka^+/+/MX1-Cre and Aurka^fl/fl/Mx1-Cre mice before and 4 weeks after pI-pC treatment were analyzed by flow cytometry. Percentages of CD45.1⁺ cells and CD45.2⁺ cells are shown. (E) Bar graph depicts percentage of donor CD45.2⁺ (green) or WT CD45.1⁺ competitor (blue) cells after pI-pC administration, as determined by CD45.1 and CD45.2 staining of peripheral blood and bone marrow LSK cells. The genotype of the donor cells is indicated on the x-axis. Data are shown as the means ± SD, n = 6. *P < .05; **P < .01; ***P < .001.