Widespread expression of Srsf2^P95H/+promotes leukocytosis and myeloid bias. (A) Srsf2^P95H transcript expression in whole BM from a control and P95H animal. (B) Experimental outline and timeframe. (C) PB indices over 22 weeks after Cre activation. (D) PB leukocyte counts and lineage distribution at 24 weeks after Cre activation (n ≥ 6 per genotype per time point). (E) Histograms and expression of CD45RB isoform on splenocytes (n = 5^+/+; n = 3 P95H⁺). (F) BM cellularity per femur. (G) Number and percentage of granulocytes and monocytes per femur. (H) Number of B cells and B-cell progenitor populations per femur. (I) Erythroid populations per femur. Number of phenotypic long-term (LT) and short-term (ST) stem-cell and multipotent progenitor (MPP) populations per femur based on lin⁻cKit⁺Sca1⁺CD34/Flt3 (J) or lin⁻cKit⁺Sca1⁺CD105/CD150 (K) phenotype. (L) Numbers of myeloerythroid progenitors per femur. (E-I) n = 5^+/+; n = 3 P95H^/+. Presented as mean ± standard error of the mean. Student t test. *P < .05, **P < .01, ***P < .001. CFU-E, colony-forming unit erythroid; GMP, granulocyte macrophage progenitor; IgM, immunoglobulin M; MkP, megakaryocyte progenitor; preMegE, premegakaryocyte erythroid progenitor.