The engraftment defect of Pak2-deleted HSCs is rescued with full-length Pak2 cDNA. (A) Engraftment of LSK BM cells. LSK cells from WT (Control) and Pak2^fl/fl mice were transduced with either Cre (Pak2^Δ/Δ) or Cre-T2A-Pak2-WT (Pak2-WT) retrovirus. Sorted EGFP⁺ cells (1 × 10⁵) were injected into lethally irradiated mice. Sixteen weeks posttransplantation, the percentage of EGFP-expressing cells in the peripheral blood was measured and the data plotted for each mouse with mean shown as horizontal bar, n = 7 to 11 mice per group. (B) Sorted EGFP⁺ LSK cells (1 × 10⁵) from WT (control) and Pak2^fl/fl (Pak2^Δ/Δ) were transduced with vectors as in Figure 5B and injected into lethally irradiated mice. Sixteen weeks posttransplantation, the percentage of engrafted EGFP-expressing cells in peripheral blood was determined. The data show mean ± SEM, n = 3 to 6 mice per group. The statistical significance was determined using the Mann-Whitney U test. ***P < .001, **P < .01.