Phenotypic characterization of primary Asxl1-MT KI mice. (A) Enumeration of peripheral WBCs, RBCs, hemoglobin (Hb), MCV, and platelet in primary Vav-Cre–negative Asxl1-MT^fl/wt (control, 70 wk old, white circle, n = 8) and Vav-Cre–positive Asxl1-MT^fl/wt mice (KI, 70 wk old, black circle, n = 11). (B) Related to A, showing the absolute number of each lineage in the PB as determined by flow cytometry analysis. (C) Proportion of CD11b⁺Gr1⁺ cells in BM from Vav-Cre–negative Asxl1-MT^fl/fl (control, 12 wk old, n = 6) and Vav-Cre–positive Asxl1-MT^fl/fl mice (KI, 12 wk old, n = 6). (D) Flow cytometry analysis of erythroid maturation with Ter119 and CD71 antibody in the BM cells in both group in primary Vav-Cre–negative Asxl1-MT^fl/fl (control, 12 wk old, white bar, n = 12) and Vav-Cre–positive Asxl1-MT^fl/fl (KI, 12 wk old, black bar, n = 12). (E) Comparison of spleen and liver weight and BM cell number in both group in Vav-Cre–negative Asxl1-MT^fl/fl (control, 12 wk old; spleen and liver, n = 6; BM, n = 5) and Vav-Cre–positive Asxl1-MT^fl/fl mice (KI, 12 wk old; spleen and liver, n = 6; BM, n = 5). (F and G) H&E staining of BM (F) and cytospin samples representing morphological abnormalities (G) in 70-wk-old Vav-Cre–positive Asxl1-MT^fl/fl BM. Arrows in F indicate megakaryocytes. Bars: 50 µm (F) and 10 µm (G). Data are presented as mean ± SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (Student’s t test).