The COP1-binding site and intact KD are necessary for the leukemogenic activity of Trib2. (A) Kaplan-Meier survival curve of mice receiving Trib2-FL, dN, dCOP, dNs, or MigR1 cotransduced with HoxA9 BM. The median survival of FL and dN mice was 83 and 79 days, respectively. (B) Wright-Giemsa–stained peripheral blood smears from mice receiving full-length Trib2 (FL, top left) and the ΔC (top right), ΔNs (bottom right), and ΔN mice (bottom left). Several leukemic blasts are indicated by the black arrows, and several metamyelocytes are shown by the white arrows. (C) Flow cytometric analysis of BM cells from C57BL/6 mice receiving HoxA9 and/or Trib2 transduced cells. Left panels, analysis of GFP (Trib2 mutants) and HoxA9-NGFR expression (percentages given) in cells obtained from BM of leukemic FL⁺HoxA9 and dN⁺HoxA9 mice, compared with C57BL/6 control mice. Flow cytometric analysis of Gr-1 and CD11b expression (middle panels) and CD34 and c-Kit expression (right panels) in the GFP⁺NGFR⁺ fractions. Representative plots are shown.