Identification of a Novel Structural Protein of Arteriviruses
| Autor: | Ketil W. Pedersen, Martin J. B. Raamsman, Hans van Tol, Antoine A. F. de Vries, Eric J. Snijder |
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| Jazyk: | angličtina |
| Rok vydání: | 1999 |
| Předmět: |
Genes
Viral Immunoelectron microscopy viruses Immunology Molecular Sequence Data RNA-dependent RNA polymerase Chick Embryo Biology Microbiology Conserved sequence Cell Line Viral Proteins Equartevirus Virology Cricetinae Animals Amino Acid Sequence Gene Peptide sequence Conserved Sequence Glycoproteins Genetics Viral Structural Proteins Base Sequence Sequence Homology Amino Acid Structure and Assembly Virion RNA Equidae Reverse genetics Open reading frame Insect Science DNA Viral Rabbits Subcellular Fractions |
| Popis: | Arteriviruses are positive-stranded RNA viruses with an efficiently organized, polycistronic genome. A short region between the replicase gene and open reading frame (ORF) 2 of the equine arteritis virus (EAV) genome was previously assumed to be untranslated. However, here we report that this segment of the EAV genome contains the 5′ part of a novel gene (ORF 2a) which is conserved in all arteriviruses. The 3′ part of EAV ORF 2a overlaps with the 5′ part of the former ORF 2 (now renamed ORF 2b), which encodes the G S glycoprotein. Both ORF 2a and ORF 2b appear to be expressed from mRNA 2, which thereby constitutes the first proven example of a bicistronic mRNA in arteriviruses. The 67-amino-acid protein encoded by EAV ORF 2a, which we have provisionally named the envelope (E) protein, is very hydrophobic and has a basic C terminus. An E protein-specific antiserum was raised and used to demonstrate the expression of the novel gene in EAV-infected cells. The EAV E protein proved to be very stable, did not form disulfide-linked oligomers, and was not N-glycosylated. Immunofluorescence and immunoelectron microscopy studies showed that the E protein associates with intracellular membranes both in EAV-infected cells and upon independent expression. An analysis of purified EAV particles revealed that the E protein is a structural protein. By using reverse genetics, we demonstrated that both the EAV E and G S proteins are essential for the production of infectious progeny virus. |
| Databáze: | OpenAIRE |
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