Epstein-Barr virus nuclear antigen 3C is a powerful repressor of transcription when tethered to DNA
| Autor: | Martin J. Allday, M Bain, Paul J. Farrell, R J Watson |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Gene Expression Regulation
Viral Herpesvirus 4 Human Saccharomyces cerevisiae Proteins Transcription Genetic Recombinant Fusion Proteins Immunology Repressor Biology Microbiology Fungal Proteins Mice Transcription (biology) Virology Tumor Cells Cultured Animals Humans Binding site Promoter Regions Genetic Antigens Viral Transcription factor chemistry.chemical_classification B-Lymphocytes Reporter gene Binding Sites General transcription factor 3T3 Cells DNA Cell Transformation Viral Molecular biology Amino acid DNA-Binding Proteins Repressor Proteins Epstein-Barr Virus Nuclear Antigens chemistry Insect Science Transcription factor II D Protein Binding Transcription Factors Research Article |
| Zdroj: | Europe PubMed Central |
| ISSN: | 1098-5514 0022-538X |
| DOI: | 10.1128/jvi.70.4.2481-2489.1996 |
| Popis: | The expression of Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) is essential for the activation and immortalization of human B lymphocytes by EBV. EBNA3C consists of 992 amino acids and includes a potential bZIP motif and regions rich in acidic, proline, and glutamine residues. Thus, EBNA3C resembles several trans regulators of gene expression. It has recently been shown that a fragment of EBNA3C can activate reporter gene expression when fused to the DNA-binding domain of GAL4 (D. Marshall and C. Sample, J. Virol. 69:3624-3630,1995). Although EBNA3C binds DNA, a specific site for EBNA3C binding has not been identified; to test the ability of full-length EBNA3C to regulate transcription, EBNA3C (amino acids 11 to 992) was fused to the DNA-binding domain of GAL4. We show that this fusion protein does not transactivate but rather is a potent repressor of reporter gene expression. Repression is dependent on the dose of GAL4-EBNA3C and on the presence of GAL4-binding sites within reporter plasmids. Repression is not restricted to B cells nor is it species or promoter specific. Repression is independent of the location of the GAL4-binding sites relative to the transcription start site. A fragment of EBNA3C (amino acids 280 to 525) which represses expression in a manner which is nearly identical to that of the full-length protein has been identified; this fragment is rich in acidic and proline residues. A second, less potent repressor region located C terminal to amino acids 280 to 525 has also been identified; this domain is rich in proline and glutamine residues. We also show binding of EBNA3C, in vitro, to the TATA-binding protein component of TFIID, and this suggests a mechanism by which EBNA3C may communicate with the basal transcription complex. |
| Databáze: | OpenAIRE |
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