Figure 6.

Structure/function analysis of Meis1 requirements in MLL transformation. (A) Western blot analysis of wild-type and mutant Meis1 proteins expressed in retroviral packaging Phoenix cells and detected with an anti-HA antibody. Identities of constructs are indicated at the tops of lanes and correspond to the schematic depictions in B. The enhanced stability of construct #2 lacking Pbx interaction motifs M1/M2 has been reported previously (G.G. Wang et al. 2005). (B) Myeloid transformation assay was performed using Meis1^−/− FL cells cotransduced with MLL-AF9 and various Meis1 constructs schematically illustrated on the left. Results from four rounds of plating are shown with each bar representing the mean ± SD of the total number of myeloid colonies per 10⁴ plated cells derived from at least three replicates.