Long-term Gata2 haploinsufficiency enhances HSC proliferation, decreases HSC abundance, and causes a reduction in common lymphoid progenitors. (A) Relative expression of Gata2 mRNA in purified hematopoietic compartments, including HSCs (LSK_CD150⁺CD48⁻), HPC1 (LSK_CD150⁻CD48⁺), HPC2 (LSK_CD150⁺CD48⁺), LMPP (LSK_CD34⁺CD135^hi), CMP (LK_CD34⁺CD16/32⁻), GMP (LK_CD34⁺CD16/32⁺), MEP (LK_CD34⁻CD16/32⁻), CLP (Lin⁻c-kit^loSca1^loCD127⁺CD135⁺), myeloid cells (Mac1⁺Gr1⁺), T cells (CD3_ε), and B cells (B220). n = 2 replicates per population. (B) Experimental design for analysis of long-term and short-term Gata2 haploinsufficiency. Gata2^+/fl; Vav-iCre⁻ (control) and Gata2^+/fl; Vav-iCre⁺ mice were analyzed at 18 to 20 months and at 8 to 12 weeks old. (C-D) Representative immunophenotypic HSPC analysis and gating scheme for Gata2 ^+/fl; Vav-iCre⁻ (control) and Gata2^+/fl; Vav-iCre⁺ mice at 18 to 20 months (C) and absolute cell count of primitive and committed hematopoietic populations (D) from control (n = 9) and Gata2^+/fl; Vav-iCre⁺ (n = 7) mice. MPPs are LSK_CD150⁻CD48⁻. Percentages represent a frequency of live nucleated BM cells. Data from 3 independent experiments. (E) Representative flow cytometry plots for cell cycle analysis of BM HSCs from Gata2^+/fl; Vav-iCre⁻ (control) and Gata2^+/fl; Vav-iCre⁺ mice at 18 to 20 months using Ki-67/4′,6-diamidino-2-phenylindole (DAPI). Bivariate plots showing the frequency of HSCs in G0 (Ki-67⁻DAPI⁻), G1 (Ki-67⁺DAPI⁻), and S/G2/M (Ki-67⁺DAPI⁺) phases from control (n = 9) and Gata2^+/fl; Vav-iCre⁺ (n = 7) mice from 3 independent experiments. (F) The percentage of BM HSCs in G0, G1, and S/G2/M cell cycle phases from aged mice (n = 9 control and 7 Gata2^+/fl; Vav-iCre⁺) and young mice (n = 6 for each genotype) from 3 independent experiments for each condition. Data presented as mean ± standard error of the mean (SEM). Statistical analysis is performed using Mann-Whitney U test. Significant data: *P < .05; **P < .01; ***P < .001.