title: Definition of subtypes in the European genotype of porcine reproductive and respiratory syndrome virus: nucleocapsid characteristics and geographical distribution in Europe.
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.
authors.affiliation: National Veterinary Research Institute, Department of Swine Diseases, OIE Reference Laboratory for PRRS, Partyzantów 57, Puławy, Poland. stadejek@piwet.pulawy.pl
authors.forename: Tomasz
authors.initials: T
authors.lastname: Stadejek
authors.forename: Martin B
authors.initials: MB
authors.lastname: Oleksiewicz
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Scherbakov
authors.forename: Anna M
authors.initials: AM
authors.lastname: Timina
authors.forename: Jonas S
authors.initials: JS
authors.lastname: Krabbe
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Chabros
authors.forename: Denis
authors.initials: D
authors.lastname: Potapchuk
mesh_terms: D000818:Animals; D005060:Europe / Q000453:epidemiology; D005838:Genotype; D005843:Geography; D019590:Nucleocapsid Proteins / Q000737:chemistry* / Q000235:genetics; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D013553:Swine Diseases / Q000821:virology
chemical_list: D019590:Nucleocapsid Proteins