Usp22 deletion in KM mice blocks myeloid cell differentiation. (A) Bone marrow (BM) cell counts and their normalization to body weight. (B) Frequency of LSK cells, CMPs, GMPs, and MEPs from the indicated mice. (C) Frequency of myeloid cells: Gr1⁺CD11b⁺ primarily associated with mature myeloid cells and Gr1^−/lowCD11b⁺ with immature cells. (D) Specific markers for detection of immature myelomonocytic cells (Ly6C^intLy6G⁻), mature neutrophils (Ly6C^intLy6G⁺), and monocytes (Ly6C⁺Ly6G⁻) after gating on CD11b⁺ cells. (E) Cytospin of BM cells isolated from the indicated mice. Wright-Giemsa stain, original magnification ×100. (F) BrdU incorporation analysis in CMPs, GMPs, and CD11b⁺ cells. (G) Colony-forming assay of whole BM (WBM) cells isolated from KM and KMUKO mice in the absence of cytokines or in the presence of GM-CSF (10 ng/mL). (H) Serial replating assay of BM cells isolated from the indicated mice in the presence of stem cell factor, interleukin-3 (IL-3), and IL-6. Representative data from 4 independent experiments. *P < .05, **P < .01, ***P < .001, unpaired 2-tailed Student t test.