EVI5 overexpression and Runx1^−/− status synergize in long-term maintenance of stem cells in vitro and in vivo. Graphic representation of (A) colony assay and (C) CAFC assay of immature cells from Runx1^+/+ and Runx1^−/− BM cells transfected with mock MIG vector, EVI5, GFI1, or EVI1, after 30 and 60 days of long-term culture. Pictures of (B) colonies and (D) morphology of cells after 30 days of long-term culture. (E) GFP chimerism in recipients of Runx1^+/+ (n = 5) and Runx1^−/− (n = 4) BM cells transfected with EVI5, 6 and 30 weeks after transplantation. Each open circle represents data from an individual mouse and the closed red circle is the average of a cohort. Statistical difference using unpaired Student t test is given at the bottom and on top. NS indicates not significant. (F) Kaplan-Meier survival curves of secondary recipients of Runx1^+/+ (blue; n = 4) and Runx1^−/− (red; n = 4) BM cells transfected with mock MIG vector (dashed line) or MIG vector carrying EVI5 (solid line). Circles represent end point of analysis.