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PubMed · 9499037

Multiple functions within the Epstein-Barr virus EBNA-3A protein.

I Cludts·P J Farrell
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Abstract

Two regions of the EBNA-3A protein of Epstein-Barr virus were shown to be capable of binding to the cell protein RBP-Jk (also known as CBF-1), a component of the Notch signaling pathway. Consistent with this binding, EBNA-3A inhibited reporter gene expression from plasmids containing RBP-Jk DNA binding sites within their promoters, including the Cp promoter. When EBNA-3A was linked to a GAL4 DNA binding domain, it repressed the activity of a promoter containing GAL4 binding sites at all plasmid concentrations tested. However, a deletion mutant of EBNA-3A lacking amino acids 100 to 364 showed a biphasic response in the GAL4 assay: it inhibited transcription at low DNA concentrations but activated it at high DNA concentrations. There appears to be a gene activation function within EBNA-3A that is masked in the full-length protein in this assay. Current models for EBNA-3 function have stressed transcription repression through binding to RBP-Jk, but we consider an alternative scheme in which the role of the binding of EBNA-3A, -3B, and -3C to RBP-Jk is to buffer the levels of active EBNA-3 protein. We have also found that the behavior of EBNA-3A in a cell fractionation procedure that distinguishes insoluble matrix from soluble cell fractions is modified by EBNA-LP, indicating a further novel level of interplay between the EBNA proteins.

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Binding SitesCell Line, TransformedDNA-Binding ProteinsEpstein-Barr Virus Nuclear AntigensHeLa CellsHerpesvirus 4, HumanHumansImmunoglobulin J Recombination Signal Sequence-Binding ProteinNuclear ProteinsPromoter Regions, GeneticRepressor ProteinsSequence DeletionTranscription, GeneticTumor Cells, CulturedJournal ArticleResearch Support, Non-U.S. Gov't

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I Cludts, P J Farrell. 1998. Multiple functions within the Epstein-Barr virus EBNA-3A protein.. https://doi.org/10.1128/jvi.72.3.1862-1869.1998

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