title: Open reading frame 2 of porcine circovirus type 2 encodes a major capsid protein.
abstract: Porcine circovirus 2 (PCV2), a single-stranded DNA virus associated with post-weaning multisystemic wasting syndrome of swine, has two potential open reading frames, ORF1 and ORF2, greater than 600 nucleotides in length. ORF1 is predicted to encode a replication-associated protein (Rep) essential for replication of viral DNA, while ORF2 contains a conserved basic amino acid sequence at the N terminus resembling that of the major structural protein of chicken anaemia virus. Thus far, the structural protein(s) of PCV2 have not been identified. In this study, a viral structural protein of 30 kDa was identified in purified PCV2 particles. ORF2 of PCV2 was cloned into a baculovirus expression vector and the gene product was expressed in insect cells. The expressed ORF2 gene product had a molecular mass of 30 kDa, similar to that detected in purified virus particles. The recombinant ORF2 protein self-assembled to form capsid-like particles when viewed by electron microscopy. Antibodies against the ORF2 protein were detected in samples of sera obtained from pigs as early as 3 weeks after experimental infection with PCV2. These results show that the major structural protein of PCV2 is encoded by ORF2 and has a molecular mass of 30 kDa.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine1, Department of Veterinary Diagnostic and Production Animal Medicine2, and Veterinary Medical Research Institute (VMRI)3, Iowa State University, 1802 Elwood Drive, Bldg 6, Ames, IA 50011-1240, USA.
authors.forename: Porntippa
authors.initials: P
authors.lastname: Nawagitgul
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine1, Department of Veterinary Diagnostic and Production Animal Medicine2, and Veterinary Medical Research Institute (VMRI)3, Iowa State University, 1802 Elwood Drive, Bldg 6, Ames, IA 50011-1240, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Morozov
authors.affiliation: Viral and Prion Diseases of Livestock Research Unit, National Animal Disease Center, ARS, USDA, Ames, Iowa, USA4.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Bolin
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine1, Department of Veterinary Diagnostic and Production Animal Medicine2, and Veterinary Medical Research Institute (VMRI)3, Iowa State University, 1802 Elwood Drive, Bldg 6, Ames, IA 50011-1240, USA.
authors.forename: Perry A
authors.initials: PA
authors.lastname: Harms
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine1, Department of Veterinary Diagnostic and Production Animal Medicine2, and Veterinary Medical Research Institute (VMRI)3, Iowa State University, 1802 Elwood Drive, Bldg 6, Ames, IA 50011-1240, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Sorden
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine1, Department of Veterinary Diagnostic and Production Animal Medicine2, and Veterinary Medical Research Institute (VMRI)3, Iowa State University, 1802 Elwood Drive, Bldg 6, Ames, IA 50011-1240, USA.
authors.forename: Prem S
authors.initials: PS
authors.lastname: Paul
mesh_terms: D000818:Animals; D016367:Baculoviridae; D002213:Capsid / Q000235:genetics*; D002478:Cells, Cultured; D017925:Circovirus / Q000235:genetics*; D003001:Cloning, Molecular; D004265:DNA Helicases / Q000235:genetics; D004261:DNA Replication; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D016366:Open Reading Frames / Q000235:genetics*; D018411:Spodoptera; D013552:Swine; D015534:Trans-Activators / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics; D015678:Viral Structural Proteins / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D015534:Trans-Activators; D014764:Viral Proteins; D015678:Viral Structural Proteins; C045264:replication initiator protein; D004265:DNA Helicases