Constitutive expression of AML1/Evi-1 in 32Dcl3 cells overcomes TGF-β–mediated inhibition of cell growth. (A) Expression of the Evi-1 and the AML1/Evi-1 proteins in stable 32Dcl3 transfectants. Clones P1 (lane 1) and P2 (lane 2) are control lines obtained from 32Dcl3 cells transfected with pMV7 followed by G418 selection. Clones E1 (lane 3) and E11 (lane 4) were established from cells transfected with pMV-Evi-1, while clones A51 (lane 5) and A53 (lane 6) were from cells transfected with pME-AML1/Evi-1. The arrows indicate the location of Evi-1 and AML1/Evi-1, and the positions of molecular-weight standards are shown at left. (B) Analysis of growth inhibition in response to TGF-β. The 32Dcl3 clones stably transfected with Evi-1 (E1 and E11) or AML1/Evi-1 (A51 and A53), and control clones (P1 and P2) were subjected to a [³H]thymidine incorporation assay in the presence of different concentrations of TGF-β. Results are expressed as percentages relative to values observed in control cultures that did not receive TGF-β. Representative values from four independent experiments are shown.