Loss of SKP2 results in defective short-term engraftment after BM transplantation. BM cells (2 × 10⁶) from male Skp2^+/+ (gray bars) or Skp2^−/− (black bars) mice were transplanted into lethally irradiated syngeneic Skp2^+/+ female nice. (A) WBC recovery at week 10 after transplantation in primary recipients and at week 5 after transplantation in secondary recipients. (B) Analysis of the LSK frequencies (left bar graph) and absolute LSK cell numbers (right bar graph) in the BM of Skp2^−/− and Skp2^+/+ donors and of first and secondary recipients at week 12 after transplantation. (C) Analysis of BrdU incorporation in LSK cells from Skp2^−/− and Skp2^+/+ donors and from first and secondary recipients at week 12 after transplantation. (D) Histograms show a representative experiment of BrdU incorporation in LSK and LK cells in Skp2^−/− and Skp2^+/+ donors and in first and secondary recipients at week 12 after transplantation. Overlaid are intensity of BrdU fluorescence in Skp2^−/− cells (red) and Skp2^+/+ cells (blue). For all graphs n = 4-8 in 2 independent experiments. Data are expressed as mean ± SEM *P < .05 vs Skp2^+/+.