Deletion of Ezh2 inhibits erythropoiesis and promotes megakaryopoiesis in Jak2V617F knock-in mice. (A) The expression of Ezh2 and levels of H3K27me3 in the total BM cells of control, Ezh2^−/−, Jak2^VF/+, and Jak2^VF/+ Ezh2^−/− mice was determined by immunoblotting at 12 weeks after pI-pC injection. β-Actin was used as a loading control. (B) RBC, (C) hematocrit (HCT), (D) WBC, (E) neutrophil (NE), (F) lymphocyte (LY), and (G) platelet (PLT) counts in the peripheral blood were assessed at 4, 8, 12, and 24 weeks after pI-pC injection in control (n = 14), Ezh2^−/− (n = 9), Jak2^VF/+ (n = 16), and Jak2^VF/+ Ezh2^−/− (n = 16) mice. (H) Reticulocytes were enumerated at 12 weeks after pI-pC injection in the peripheral blood of control, Ezh2^−/−, Jak2^VF/+, and Jak2^VF/+ Ezh2^−/− mice. (I) Spleen size/weight was decreased in Jak2^VF/+ Ezh2^−/− mice compared with Jak2^VF/+ mice, but was still significantly greater than those in control or Ezh2^−/− mice (n = 5-10). One-way ANOVA was used for comparisons of all 4 groups of mice, and the Student t test was used to compare between 2 groups of mice (*P < .05; **P < .005).