Competitive repopulation assays. (A) Schematic drawing of the experimental setup. (B) BM cells from a wild-type control mouse (WT, black symbols), from MxCre;FF1 mouse (Mx, red symbols), and a SclCre;FF1 mouse (Scl, green symbols) were harvested at 6 and 8 weeks after induction with pIpC or tamoxifen, respectively, mixed with BM cells from a UBC-GFP transgenic mouse at a 1:1 ratio, and transplanted into 7 lethally irradiated recipients per group (2 × 106 BM cells each). The time course of the blood counts and the percentages of chimerism (bottom panel) as determined by flow cytometry of GFP− cells are shown for the erythroid (Ter119), platelet (CD61), and granulocytic (Gr1) lineages in peripheral blood. Error bars represent SEM. (C) Survival probabilities of the transplantation recipients (Kaplan-Meier plot). Color coding is as in panel B. (D) Ratio between human JAK2-V617F and mouse Jak2 in the BM of mice transplanted with the MxCre;FF1 and UBC-GFP BM cells in a 1:1 ratio. Sampling was performed 35 weeks after transplantation. (E) Percentages of chimerism in the BM and spleens of transplanted mice as determined by the proportion of GFP− cells. (F) Percentages of LSK cells within the lineage− BM cell population and the LSK chimerism determined as the proportion of GFP− cells in the BM of recipient mice. Error bars represent SEM. One-way ANOVA is shown for comparisons between mice transplanted with wild-type (C57BL/6 and UBC-GFP) and mutant (MxCre;FF1 and UBC-GFP) BM cells. ns indicates not significant. *P ≤ .05; **P ≤ .01; ***P ≤ .001.