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

• Published in: Archives of virology 2008-08, Vol.153 (8), p.1479-1488
• Main Authors: Stadejek, Tomasz, Oleksiewicz, Martin B, Scherbakov, Alexei V, Timina, Anna M, Krabbe, Jonas S, Chabros, Katarzyna, Potapchuk, Denis
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Biomedical and Life Sciences; Biomedicine; Escherichia; Europe - epidemiology; Genotype; Genotype & phenotype; Geography; Hogs; Infectious Diseases; Medical Microbiology; Nucleocapsid Proteins - chemistry; Nucleocapsid Proteins - genetics; Original Article; Porcine Reproductive and Respiratory Syndrome - epidemiology; Porcine Reproductive and Respiratory Syndrome - virology; Porcine respiratory and reproductive syndrome virus; 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; Proteins; Swine Diseases - virology; Vaccines; Virology; Viruses
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-008-0146-2

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.