Megakaryocyte-restricted deletion of Ezh2 contributes to the progression of JAK2^V617F-induced fibrosis. (a) qRT-PCR analysis of Ezh2 in LSKs, MkPs, and GMPs from WT and JAK2^V617F/Ezh2^MkΔ/Δ cells at 2–3 mo after transplantation. (b) CBC of WT (n = 5), Ezh2^MkΔ/Δ (n = 4), JAK2^V617F (n = 6), and JAK2^V617F/Ezh2^MkΔ/Δ (n = 10) mice 5 mo after transplantation. (c) Spleen weight of WT (n = 5), Ezh2^MkΔ/Δ (n = 4), JAK2^V617F (n = 4), and JAK2^V617F/Ezh2^MkΔ/Δ (n = 5) mice 5 mo after transplantation. (d) Proportions of LSK cells and MkPs in the spleen of WT and JAK2^V617F/Ezh2^MkΔ/Δ mice (n = 3–5) 5 mo after transplantation. (e) Histology of the BM and spleen from WT, Ezh2^MkΔ/Δ, JAK2^V617F, and JAK2^V617F/Ezh2^MkΔ/Δ mice observed by hematoxylin-eosin staining (middle) and silver staining (top and bottom). Bars, 100 µm. (f) BM fibrosis grading (grades 0–3; Thiele et al., 2005) of WT, Ezh2^MkΔ/Δ, JAK2^V617F, and JAK2^V617F/Ezh2^MkΔ/Δ (n = 3–5) mice 5 mo after transplantation. (a–d) Bars and asterisks show the mean ± SEM and *, P < 0.05; and **, P < 0.01 by the Student’s t test. (f) Asterisk shows *, P < 0.05 by the Mann–Whitney U test; two independent experiments.