Genetic polymorphism of the nsp2 gene in North American type--porcine reproductive and respiratory syndrome virus.
We determined the complete nucleotide sequence of EDRD-1, a Japanese strain of the North American type-Porcine reproductive and respiratory syndrome virus (PRRSV), and identified a novel 117-base deletion and 108-base insertion previously reported in the nsp2 gene of the SP strain, which contains the largest genome among PRRSV strains. Based on genetic analysis of the partial nsp2 gene in 30 additional Japanese isolates and 50 strains from various countries, we classified North American-type PRRSVs into three nsp2-types, represented by EDRD-1, which contains the 117-base deletion and 108-base insertion; prototypic VR-2332, which does not contain the deletion and insertion; and SP, which contains only the 108-base insertion. The three nsp2-types were phylogenetically separated, suggesting that these structural changes only occurred at earlier stages of viral evolution. In the nsp2 genes, we identified an additional 19 deletions ranging from 3 to 378 bases and 2 insertions of 3 and 21 bases which were not common within each nsp2-type, suggesting that these changes occurred at later stages of viral evolution. In addition, our results suggest that the three nsp2-types can be rapidly differentiated by RT-PCR using their polymorphisms as natural tags.
Research Team for Viral Diseases, National Institute of Animal Health, Tsukuba, Ibaraki 305-0856, Japan. mnyoshii@yahoo.co.jp
Masaaki
M
Yoshii
Tatsuyuki
T
Okinaga
Ayako
A
Miyazaki
Kanako
K
Kato
Hidetoshi
H
Ikeda
Hiroshi
H
Tsunemitsu
D000818:Animals; D019143:Evolution, Molecular; D016679:Genome, Viral; D054643:INDEL Mutation; D007564:Japan; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000235:genetics*
D012367:RNA, Viral; D017361:Viral Nonstructural Proteins