title: Evidence for the multimeric nature and cell binding ability of avian reovirus sigma 3 protein.
abstract: It has been suggested that avian reovirus sigma 3 protein is analogous to sigma 1 trimer, the mammalian reovirus attachment protein. We have investigated the multimeric nature and cell binding ability of sigma 3 protein. The data presented here demonstrate that sigma 3 protein is a multimer in its undisrupted form as determined by SDS-PAGE in non-dissociating conditions. However, virion-associated sigma 3 protein and COS-7 cell-expressed protein behaved differently in SDS-PAGE, suggesting a need for virus-associated factor(s) to control the multimerization of the protein. The data also show that Escherichia coli expressed sigma 3 fusion protein (sigma 3-MBP) in its multimeric form is capable of attaching to Vero cells. The binding was found to be specific and receptor mediated by the fact that it was inhibited by a monoclonal antibody specific for sigma 3 protein and by competition with avian reovirus particles. As determined by a reverse experiment, sigma 3-MBP was also able to reduce the virus p.f.u. in monolayer cell cultures, indicating the important role of sigma 3 protein in the initiation of virus infection.
authors.affiliation: Section de virologie, Faculté de Médecine vétérínaire, Université de Montréal, Québec, Canada.
authors.forename: M R
authors.initials: MR
authors.lastname: Shapouri
authors.forename: M
authors.initials: M
authors.lastname: Arella
authors.forename: A
authors.initials: A
authors.lastname: Silim
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001665:Binding Sites; D001717:Birds; D015153:Blotting, Western; D036022:Capsid Proteins; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D058619:Maltose-Binding Proteins; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D016297:Mutagenesis, Site-Directed; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012087:Reoviridae / Q000502:physiology*; D014709:Vero Cells; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D014771:Virion / Q000502:physiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D000911:Antibodies, Monoclonal; D036022:Capsid Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C461599:maltose transport system, E coli; C053179:sigma protein 3, Reovirus