title: Bovine coronavirus nonstructural protein ns2 is a phosphoprotein.
abstract: To investigate the nature of the bovine coronavirus (BCV) ns2 protein, the gene encoding this protein was cloned and was expressed as a beta-galactosidase fusion protein. Antiserum raised against this protein reacted specifically with BCV-infected fixed cells in indirect immunofluorescence microscopy and precipitated an in vitro synthesized product approximately 32-kDa in molecular weight and an equivalent protein from BCV-infected cells. The synthesis of ns2 was found to be similar to the structural proteins of BCV and pulse-chase experiments indicated that ns2 protein was stable and that it accumulated in BCV-infected cells. Synthesis of ns2 in the presence of [32P] orthophosphate revealed that it is a phosphoprotein. Phosphoamino acid analysis confirmed the phosphorylated nature of ns2 and identified serine and threonine as its phosphorylated amino acid residues. This is the first demonstration of a phosphorylated nonstructural protein in coronavirus-infected cells.
authors.affiliation: Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada.
authors.forename: G J
authors.initials: GJ
authors.lastname: Cox
authors.forename: M D
authors.initials: MD
authors.lastname: Parker
authors.forename: L A
authors.initials: LA
authors.lastname: Babiuk
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002213:Capsid / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D002417:Cattle; D002460:Cell Line; D003332:Coronaviridae / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D005814:Genes, Viral; D007106:Immune Sera; D015151:Immunoblotting; D007700:Kinetics; D008970:Molecular Weight; D010750:Phosphoproteins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D014758:Viral Core Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D017361:Viral Nonstructural Proteins
chemical_list: D000596:Amino Acids; D007106:Immune Sera; D010750:Phosphoproteins; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins