Lysine acetyltransferases modulate the activity of many genes by modifying the lysine residues of both core histones and transcription-related factors. These modifications are tightly controlled in the cell because they are involved in vital processes such as cell cycle progression, differentiation, and apoptosis. Therefore, any deregulation of acetylation/deacetylation equilibrium or inappropriate modifications could lead to different diseases. Since previous studies have shown that some oncoproteins also undergo this modification, acetylation could be involved in the processes of cell transformation and oncogenesis. Here, we report that AML1/ MDS1/EVII (AME), a repressor produced by the t(3;21) associated with human leukemia, physically interacts with the acetyltransferases P/CAF and GCN5. Our data suggest that AM E has at least two binding sites for these acetyltransferases, one of which is in the Runt domain. Both P/CAF and GCN5 efficiently acetylate AME in vivo in the central region. AME acetylation has no effect on its interaction with the co-repressor CtBP1. Finally, we demonstrate that the co-expression of AME and either P/CAF or GCN5 abrogates the repression of an AML1-dependent reporter gene. (C) 2003 Elsevier Inc. All rights reserved.