Inv(3)-driven EVI1 expression promotes expansion of multipotent progenitors, but not LT-HSC. (A) Mouse models used for evaluation of the individual or combinatorial contributions of EVI1 overexpression and Gata2 haploinsufficiency to leukemogenesis. Twelve-week-old mice were used for this study. (B) Representative flow cytometric profiles of lineage-negative fractions from 12-week-old WT, Gata2^+/gfp, 3q21q26-EVI1, and 3q21q26-EVI1::Gata2^+/gfp bone marrows. Further analysis of the LSK fraction (top) is shown in the middle panels, whereas analyses of the Flt3-low fraction in the middle panels are shown in the bottom panels. (C) Absolute numbers of LSK cells in the bone marrows from 12-week-old WT (blue circle), Gata2^+/gfp (red square), 3q21q26-EVI1 (green triangle), and 3q21q26-EVI1::Gata2^+/gfp (purple reverse triangle) mice. (D) Percentages of LT-HSC, ST-HSC, MPP2, MPP3, and MPP4 in LSK fractions from 12-week-old WT (blue circle), Gata2^+/gfp (red square), 3q21q26-EVI1 (green triangle), and 3q21q26-EVI1::Gata2^+/gfp (purple reverse triangle) mice. (E) Absolute numbers of LT-HSC, ST-HSC, MPP2, MPP3, and MPP4 in the bone marrows from 12-week-old WT (blue circle), Gata2^+/gfp (red square), 3q21q26-EVI1 (green triangle), and 3q21q26-EVI1::Gata2^+/gfp (purple reverse triangle) mice. Values represent the means ± SD. *P < .05; **P < .01 (1-way analysis of variance [ANOVA]).