The loss of Ezh2 severely compromises hematopoiesis in the presence of the JAK2V617F mutant. (a) Experimental scheme of our model mouse using JAK2V617F transgenic and Ezh2 conditional KO BM cells. (b) qRT-PCR analysis of Ezh2 in LSKs and MEPs from WT, Ezh2Δ/Δ, JAK2V617F, and JAK2V617F/Ezh2Δ/Δ mice 4 wk after the Cre-mediated deletion of Ezh2. (c) Verification of elimination of Ezh2 protein and levels of H3K27me3 in LK cells detected by Western blotting. (d) CBC of WT (n = 5), Ezh2Δ/Δ (n = 5), JAK2V617F (n = 5), and JAK2V617F/Ezh2Δ/Δ (n = 10) mice 4 wk after the deletion of Ezh2 and moribund JAK2V617F/Ezh2Δ/Δ mice (n = 10). (e) Proportions of myeloid (Gr-1+ and/or Mac-1+), B220+ B cells, and CD4+ or CD8+ T cells among CD45.2+ donor–derived hematopoietic cells in the PB (JAK2V617F/Ezh2Δ/Δ n = 10, others n = 5). (f) Dysplastic red blood cells in JAK2V617F/Ezh2Δ/Δ mice observed by May-Grünewald-Giemsa staining. Bars, 10 µm. (g) Kaplan-Meier survival curves of WT (n = 6), Ezh2Δ/Δ (n = 6), JAK2V617F (n = 8), JAK2V617F/Ezh2Δ/+ (n = 9), and JAK2V617F/Ezh2Δ/Δ (n = 10) mice; three independent experiments were performed. ***, P < 0.0001 by the log-rank test. (h) CBC of WT (n = 5), Ezh2Δ/Δ (n = 5), JAK2V617F (n = 6), and JAK2V617F/Ezh2Δ/+ (n = 9) mice 4 mo after the deletion of Ezh2. (a, d, e, and h) Bars and asterisks show the mean ± SEM and *, P < 0.05; **, P < 0.01; and ***, P < 0.001 by the Student’s t test; two independent experiments. (b and c) Data are shown as mean ± SD; two independent experiments.
