LOCALIZATION OF THE C-ETS-2 TRANSACTIVATION DOMAIN

The human ets-2 proto-oncogene is one of the homologs of the v-ets gene, found in avian acutely transforming retrovirus E26 (D. Leprince, A. Gegonne, J. Call, C. de Taisne, A. Schneeberger, C. Lagrou, and D. Stehelin, Nature [London] 306:395-397, 1983; M. F. Nunn, P. H. Seeburg, C. Moscovici, and P. H. Duesberg, Nature [London] 306:391-395, 1983)., which causes leukemia in chickens. We used the DNA-binding domain of yeast transcriptional activator GAL4 to locate the transactivation region of human ets-2. The transactivation domain of ets-2 was found in the N-terminal part of the protein, which is homologous to ets-1, and can be disrupted by deletion of a stretch of acidic amino acid residues. A transactivation-deficient mutant of ets-2 failed to transform Rat-1 cells and suppressed the transforming activity of coexpressed wild-type ets-2. A mutation in the putative DNA-binding region of ets-2 abolished transforming activity. We show that the motif crucial for ets-2 transactivation capability is necessary for transforming activity in Rat-I cells. Mutant ets-2 protein that lacks the transactivation domain has a dominant negative effect on transformation by wild-type ets-2. We were unable to detect ets-2-dependent transcriptional regulation of several enhancers containing ets-binding motifs.