Intrinsic myeloid bias and impaired repopulation of Srsf2^P95H/+HSCs. (A) Experimental outline and timeframe for transplantation using R26-CreER model. (B) PB chimerism. (C) PB leukocyte counts in the recipients of R26-CreER Srsf2^+/+ (control) and R26-CreER Srsf2^P95H/+ BM over time. Number and percentage of donor-derived granulocytes (D) or B lymphocytes (E) in the PB over time. (F) Quantitation and representative fluorescence-activated cell sorting (FACS) plots of Ly6c/CD11b populations in the CD45.2 donor-derived PB populations: fraction I = Ly6C^hi/Mac1⁻; fraction II = monocytes; fraction V = neutrophil precursors; fraction VII = macrophages. (G) Percentage of CD45.2⁺ granulocytes, macrophages, and B-cell populations in the BM, respectively. (H) Percentage of CD45.2⁺ granulocytes and macrophages in the spleen. (I) Experimental outline and timeframe for transplantation using hScl-CreER model. PB chimerism (J) and eYFP percentage (K) within the CD45.2 population over time. PB leukocyte counts (L) and BM cellularity (M) at 30 weeks posttransplantation. (N) Analysis of lineage distribution within the eYFP/CD45.2 population at 28 weeks after Cre activation. (O) FACS plots of the eYFP⁺ CD11b/Gr-1 populations in the BM of recipients of the indicated genotype. Presented as mean ± standard error of the mean; n = 5 recipients per genotype per transplantation model at initiation of transplantation. Student t test or analysis of variance with repeated measures. *P < .05, **P < .01, ***P < .001. BMT, BM transplantation.