title: Binding of the heterogeneous ribonucleoprotein K (hnRNP K) to the Epstein-Barr virus nuclear antigen 2 (EBNA2) enhances viral LMP2A expression.
abstract: The Epstein-Barr Virus (EBV) -encoded EBNA2 protein, which is essential for the in vitro transformation of B-lymphocytes, interferes with cellular processes by binding to proteins via conserved sequence motifs. Its Arginine-Glycine (RG) repeat element contains either symmetrically or asymmetrically di-methylated arginine residues (SDMA and ADMA, respectively). EBNA2 binds via its SDMA-modified RG-repeat to the survival motor neurons protein (SMN) and via the ADMA-RG-repeat to the NP9 protein of the human endogenous retrovirus K (HERV-K (HML-2) Type 1). The hypothesis of this work was that the methylated RG-repeat mimics an epitope shared with cellular proteins that is used for interaction with target structures. With monoclonal antibodies against the modified RG-repeat, we indeed identified cellular homologues that apparently have the same surface structure as methylated EBNA2. With the SDMA-specific antibodies, we precipitated the Sm protein D3 (SmD3) which, like EBNA2, binds via its SDMA-modified RG-repeat to SMN. With the ADMA-specific antibodies, we precipitated the heterogeneous ribonucleoprotein K (hnRNP K). Specific binding of the ADMA- antibody to hnRNP K was demonstrated using E. coli expressed/ADMA-methylated hnRNP K. In addition, we show that EBNA2 and hnRNP K form a complex in EBV- infected B-cells. Finally, hnRNP K, when co-expressed with EBNA2, strongly enhances viral latent membrane protein 2A (LMP2A) expression by an unknown mechanism as we did not detect a direct association of hnRNP K with DNA-bound EBNA2 in gel shift experiments. Our data support the notion that the methylated surface of EBNA2 mimics the surface structure of cellular proteins to interfere with or co-opt their functional properties.
authors.affiliation: Institute of Virology, Saarland University Medical School, Homburg/Saar, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Gross
authors.forename: Christine
authors.initials: C
authors.lastname: Hennard
authors.forename: Ilias
authors.initials: I
authors.lastname: Masouris
authors.forename: Christian
authors.initials: C
authors.lastname: Cassel
authors.forename: Stephanie
authors.initials: S
authors.lastname: Barth
authors.forename: Ute
authors.initials: U
authors.lastname: Stober-Grässer
authors.forename: Alfredo
authors.initials: A
authors.lastname: Mamiani
authors.forename: Bodo
authors.initials: B
authors.lastname: Moritz
authors.forename: Dirk
authors.initials: D
authors.lastname: Ostareck
authors.forename: Antje
authors.initials: A
authors.lastname: Ostareck-Lederer
authors.forename: Nils
authors.initials: N
authors.lastname: Neuenkirchen
authors.forename: Utz
authors.initials: U
authors.lastname: Fischer
authors.forename: Wen
authors.initials: W
authors.lastname: Deng
authors.forename: Heinrich
authors.initials: H
authors.lastname: Leonhardt
authors.forename: Elfriede
authors.initials: E
authors.lastname: Noessner
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.forename: Friedrich A
authors.initials: FA
authors.lastname: Grässer
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D020031:Epstein-Barr Virus Infections / Q000378:metabolism; D019309:Epstein-Barr Virus Nuclear Antigens / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000502:physiology; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008745:Methylation; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D021381:Protein Transport; D020449:Repetitive Sequences, Amino Acid; D014162:Transfection; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D055517:snRNP Core Proteins / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; C402641:EBNA-2 protein, Human herpesvirus 4; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D019309:Epstein-Barr Virus Nuclear Antigens; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D046912:Multiprotein Complexes; D050505:Mutant Proteins; C526412:SNRPD3 protein, human; D014763:Viral Matrix Proteins; D014764:Viral Proteins; D055517:snRNP Core Proteins; C024917:symmetric dimethylarginine; C018524:N,N-dimethylarginine; D004247:DNA; D001120:Arginine