Direct interaction between nucleosome assembly protein 1 and the papillomavirus E2 proteins involved in activation of transcription.

Using a yeast two-hybrid screen, we identified human nucleosome assembly protein 1 (hNAP-1) as a protein interacting with the activation domain of the transcriptional activator encoded by papillomaviruses (PVs), the E2 protein. We show that the interaction between E2 and hNAP-1 is direct and not merely mediated by the transcriptional ...
coactivator p300, which is bound by both proteins. Coexpression of hNAP-1 strongly enhances activation by E2, indicating a functional interaction as well. E2 binds to at least two separate domains within hNAP-1, one within the C terminus and an internal domain. The binding of E2 to hNAP-1 is necessary for cooperativity between the factors. Moreover, the N-terminal 91 amino acids are crucial for the transcriptional activity of hNAP-1, since deletion mutants lacking this N-terminal portion fail to cooperate with E2. We provide evidence that hNAP-1, E2, and p300 can form a ternary complex efficient in the activation of transcription. We also show that p53 directly interacts with hNAP-1, indicating that transcriptional activators in addition to PV E2 interact with hNAP-1. These results suggest that the binding of sequence-specific DNA binding proteins to hNAP-1 may be an important step contributing to the activation of transcription.
Mesh Terms:
Acetyltransferases, Animals, Cell Cycle Proteins, Cell Line, DNA-Binding Proteins, Genes, Reporter, Histone Acetyltransferases, Humans, Macromolecular Substances, Nuclear Proteins, Nucleosome Assembly Protein 1, Protein Binding, Protein Structure, Tertiary, Proteins, Recombinant Fusion Proteins, Trans-Activators, Transcription Factors, Transcription, Genetic, Transcriptional Activation, Two-Hybrid System Techniques, Viral Proteins, p300-CBP Transcription Factors
Mol. Cell. Biol.
Date: Mar. 01, 2004
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