Zeb2 deletion causes cytopenia in multiple hematopoietic lineages. (A) Absolute numbers of mature blood cells in mice at 8 weeks after Poly(I:C) administration significantly reduces leukocytes, erythrocytes, and thrombocytes in Zeb2^Δ/ΔMx1-Cre mice. PLT, platelet; RBC, red blood cell; WBC, white blood cell. (B) Representative images of peripheral blood smears from control and Zeb2^Δ/ΔMx1-Cre mice. Smears demonstrate absence of regular thrombocytes but sporadic giant platelets in absence of Zeb2 (arrows). (C) Representative FACS plots and gating strategy of peripheral blood analyses at 8 weeks after Poly(I:C) administration to define monocyte (Ly6G⁻CD11b⁺) frequency, immature and mature granulocytes (Ly6G^dimCD11b⁺ and Ly6G^highCD11b⁺, respectively), B lymphocytes (B220⁺), and T lymphocytes (CD3e⁺). (D) Quantified absolute cell numbers of the leukocyte subsets per microliter of blood of control and Zeb2^Δ/ΔMx1-Cre mice revealed significant reduction in B cells, monocytes, and immature granulocytes, but comparable counts of mature granulocytes and T cells. (E) Histologic examination of Zeb2^Δ/ΔMx1-Cre and control femurs shows comparable BM cellularity. Bar graphs represent 100 µm. (F) Analyses of BM composition of different hematopoietic lineages show a predominant occurrence of granulopoiesis with a relative decrease of all other lineages. Data are from 4 independent Zeb2 inactivation experiments using in total 12 mice (A and D), and 3 experiments with 6 mice per genotype (F). Mean ± SEM is shown. Unpaired, 2-tailed t test was performed to determine significance *P < .05, **P < .01; ***P < .001.