Abstract
During the G(1) phase of the cell cycle, an E2F-RB complex represses transcription, via the recruitment of histone deacetylase activity. Phosphorylation of RB at the G(1)/S boundary generates a pool of 'free' E2F, which then stimulates transcription of S-phase genes. Given that E2F1 activity is stimulated by p300/CBP acetylase and repressed by an RB-associated deacetylase, we asked if E2F1 was subject to modification by acetylation. We show that the p300/CBP-associated factor P/CAF, and to a lesser extent p300/CBP itself, can acetylate E2F1 in vitro and that intracellular E2F1 is acetylated. The acetylation sites lie adjacent to the E2F1 DNA-binding domain and involve lysine residues highly conserved in E2F1, 2 and 3. Acetylation by P/CAF has three functional consequences on E2F1 activity: increased DNA-binding ability, activation potential and protein half-life. These results suggest that acetylation stimulates the functions of the non-RB bound 'free' form of E2F1. Consistent with this, we find that the RB-associated histone deacetylase can deacetylate E2F1. These results identify acetylation as a novel regulatory modification that stimulates E2F1's activation functions.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylation
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Acetyltransferases / metabolism
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Amino Acid Sequence
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Animals
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Base Sequence
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Binding Sites / genetics
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Carrier Proteins*
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Line
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DNA / genetics
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DNA / metabolism
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DNA-Binding Proteins*
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E2F Transcription Factors
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E2F1 Transcription Factor
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G1 Phase
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Histone Acetyltransferases
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Histone Deacetylases / metabolism
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Humans
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In Vitro Techniques
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Nuclear Proteins / metabolism
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Retinoblastoma Protein / metabolism
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Retinoblastoma-Binding Protein 1
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S Phase
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Sequence Homology, Amino Acid
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Trans-Activators / metabolism
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Transcription Factor DP1
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcriptional Activation
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p300-CBP Transcription Factors
Substances
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Carrier Proteins
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Cell Cycle Proteins
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DNA-Binding Proteins
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E2F Transcription Factors
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E2F1 Transcription Factor
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E2F1 protein, human
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Nuclear Proteins
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Retinoblastoma Protein
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Retinoblastoma-Binding Protein 1
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Trans-Activators
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Transcription Factor DP1
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Transcription Factors
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DNA
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Acetyltransferases
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Histone Acetyltransferases
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p300-CBP Transcription Factors
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p300-CBP-associated factor
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Histone Deacetylases