Full-length sequence of a Canadian porcine reproductive and respiratory syndrome virus (PRRSV) isolate

Citation
S. Wootton et al., Full-length sequence of a Canadian porcine reproductive and respiratory syndrome virus (PRRSV) isolate, ARCH VIROL, 145(11), 2000, pp. 2297-2323
Citations number
56
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF VIROLOGY
ISSN journal
0304-8608 → ACNP
Volume
145
Issue
11
Year of publication
2000
Pages
2297 - 2323
Database
ISI
SICI code
0304-8608(2000)145:11<2297:FSOACP>2.0.ZU;2-V
Abstract
Presently, one of the most economically important pathogens affecting swine is the porcine reproductive and respiratory syndrome virus (PRRSV). This v irus is prevalent in herds throughout the world and continues to pose a sig nificant threat as newer and more virulent disease phenotypes emerge. In th is report we describe the full-length nucleotide sequence of a Canadian PRR SV isolate, designated PA8. A consecutive sequence of 15,411 nucleotides wa s obtained from a set of overlapping cDNA clones. In order to determine the extent of genetic variation among isolates recovered from swine in Canada and the US, as well as to understand the molecular mechanisms governing the evolution of PRRSV, the full-length sequence of PA8 was compared with that of two US isolates, VR2332 and 16244B. The genomic sequence of PA8 shared 98.2% and 99.2% identity with 16244B and VR2332, respectively. The untransl ated regions (UTR) at the 5' and 3/ ends of the genome were very well conse rved. Notable exceptions include an eight nucleotide difference at the 5' e nd of the 5' UTR of VR2332 relative to PA8 and 16',44B and a two nucleotide difference in the 3' UTR of PA8 relative to VR2332 and 16244B. In contrast to PA8 and VR2332, 16244B possessed two nucleotide differences within the RNA pseudoknot structure of the ribosomal frameshift region between open re ading frame (ORF)la and ORFlb. Amino acid differences were distributed thro ughout the genome, however they appeared to be most extensive in Nsp1 beta and ORF5 of the nonstructural and structural coding regions, respectively, suggesting that the evolutionary pressure to conserve these viral genes is somewhat lower.