Stem cell phenotype of Csnk1a1^fl/+, Egr1^–/+ and Csnk1a1^fl/+Egr1^–/+ mice. (A) White blood cell counts recorded at 4, 7, 11, 16, and 20 weeks after transplant. (B) Frequency of CD11b⁺ myeloid cells of viable blood cells at 20 weeks after transplant (euthanize). (C) Frequency of CD45.2⁺ cells in bone marrow LK (Lin^– and ckit⁺) and LSK (Lin^– Sca1⁺ ckit⁺) in bone marrow at 20 weeks after transplant (euthanize). (D) Frequency of MPP (CD48⁺CD150^–LSK), ST-HSC (CD48-CD150- LSK), and long-term hematopoietic stem cells (CD48-CD150⁺ LSK) in CD45.2⁺ LSK cells in the bone marrow at harvest. (E) Colony forming potential of sorted LSK cells from Mx1Cre, Csnk1a1^fl/+, Egr1^–/+, and Csnk1a1^fl/+Egr1^–/+ mice plated in methylcellulose at first and second plating. (F) Gene set enrichment analysis of Hallmark pathways on RNA sequencing data of sorted LSK; columns signify enriched pathways of contrast Egr1^–/+ vs Mx1Cre⁺, Csnk1a1^fl/+ vs Mx1Cre⁺, and Csnk1a1^fl/+Egr1^–/+ vs Mx1Cre⁺. (G) Characterization of cell type proportions of sorted LSK based on Cibersort tumor profiling. (H) Ridgeline plot comparing gene distribution of G2M- and S-phase genes based on Cibersort tumor profiling. (I) Intracellular Ki67 and 7-AAD staining to discriminate the cell cycle phases G0, G1, S-G2-M) within Mx1Cre, Csnk1a1^fl/+, Egr1^–/+ and Csnk1a1^fl/+Egr1^–/+ HoxB8-Flt3 cells. (J) Flow cytometric analysis of the competitive coculture assay of HOXB8 cells derived from Mx1Cre (GFP⁺) against HOXB8 cells derived from Csnk1a1^fl/+, Egr1^–/+, and Csnk1a1^fl/+Egr1^–/+ HoxB8-Flt3 cells (GFP^–) over 6 days. Data represent the mean ± standard error of the mean. Statistical test was performed by 1-way analysis of variance with Dunnet post hoc test to compare each genotype to control (Mx1Cre). Only significant results are marked and all other comparisons were nonsignificant. HGB, hemoglobin; IFN, interferon; PBS, phosphate-buffered saline; WBC, white blood cell.