Definition of subtypes in the European genotype of porcine reproductive and respiratory syndrome virus: nucleocapsid characteristics and geographical distribution in Europe

Arch Virol. 2008;153(8):1479-88. doi: 10.1007/s00705-008-0146-2. Epub 2008 Jul 1.

Abstract

The nucleocapsid protein of the European genotype of porcine reproductive and respiratory syndrome virus (type 1, PRRSV-1) exhibited extensive size polymorphism (124-130 amino acids), correlating with phylogenetic grouping of ORF7 as well as ORF5 nucleotide sequences, thereby validating ORF7 size as an independent PRRSV-1 subtype marker. Based on new sequence information from the Russian Federation, we propose division of European genotype PRRSV-1 into 3 subtypes: a pan-European subtype 1 and East European subtypes 2 and 3, with nucleocapsid protein sizes of 128, 125 and 124 amino acids, respectively. The genetic differences between European genotype PRRSV subtypes affected diagnostic RT-PCR primer binding sites. Using Escherichia coli-expressed ORF7 protein, we confirmed that even the relatively closely related PRRSV subtypes 2 and 3 were antigenically different. Finally, the isoelectric point (pI) correlated with the nucleocapsid protein size for European genotype PRRSV subtypes, suggesting subtype-specific compensatory structural changes associated with subtype-specific ORF7 sizes. Thus, the new ORF7-based subtype division of PRRSV-1 proposed here is biologically meaningful and practically relevant.

MeSH terms

  • Animals
  • Europe / epidemiology
  • Genotype
  • Geography
  • Nucleocapsid Proteins / chemistry*
  • Nucleocapsid Proteins / genetics
  • Porcine Reproductive and Respiratory Syndrome / epidemiology*
  • Porcine Reproductive and Respiratory Syndrome / virology
  • Porcine respiratory and reproductive syndrome virus / classification*
  • Porcine respiratory and reproductive syndrome virus / genetics
  • Porcine respiratory and reproductive syndrome virus / immunology
  • Porcine respiratory and reproductive syndrome virus / isolation & purification
  • Swine Diseases / virology

Substances

  • Nucleocapsid Proteins