title: Phosphorylation of the porcine reproductive and respiratory syndrome virus nucleocapsid protein.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is a cytoplasmic RNA virus with the unique or unusual feature of having a nucleocapsid (N) protein that is specifically transported to the nucleolus of virus-infected cells. In this communication, we show that the N protein is a phosphoprotein. Phosphoamino acid analysis of authentic and recombinant N proteins demonstrated that serine residues were exclusively phosphorylated. The pattern of phosphorylated N protein cellular distribution in comparison with that of [(35)S]methionine-labeled N protein suggested that phosphorylation does not influence subcellular localization of the protein. Time course studies showed that phosphorylation occurred during, or shortly after, synthesis of the N protein and that the protein remained stably phosphorylated throughout the life cycle of the virus to the extent that phosphorylated N protein was found in the mature virion. Two-dimensional electrophoresis and acid-urea gel electrophoresis showed that one species of the N protein is predominant in virus-infected cells, suggesting that multiple phosphorylated isoforms of N do not exist.
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Wootton
authors.forename: Raymond R R
authors.initials: RR
authors.lastname: Rowland
authors.forename: Dongwan
authors.initials: D
authors.lastname: Yoo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002467:Cell Nucleus / Q000378:metabolism; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D019316:Porcine respiratory and reproductive syndrome virus / Q000378:metabolism*; D013552:Swine
chemical_list: D019590:Nucleocapsid Proteins; D010750:Phosphoproteins