North American and European porcine reproductive and respiratory syndrome viruses differ in non-structural protein coding regions.

Abstract

Although North American and European serotypes of porcine reproductive and respiratory syndrome virus (PRRSV) are recognized, only the genome of the European Lelystad strain (LV) has been sequenced completely. Here, the genome of the pathogenic North American PRRSV isolate 16244B has been sequenced and compared with LV. The genomic organization of 16244B was the same as LV but with only 63n4 % nucleotide identity. The 189 nucleotide 5h non-coding region (NCR) of 16244B was distinct from the LV NCR, with good conservation (83 %) only over a 43 base region immediately upstream of open reading frame (ORF) 1a. Major differences were found in the region encoding the non-structural part of the ORF1a polyprotein, which shared only 47 % amino acid identity over 2503 residues of the six non-structural proteins (Nsps) encoded. Nsp2, thought to have a species-specific function, showed the greatest divergence, sharing only 32 % amino acid identity with LV and containing 120 additional amino acids in the central region. Nsps encoded by the 5h-proximal and central regions of ORF1b had from 66 to 75 % amino acid identity ; however, the carboxy-terminal protein CP4 was distinct (42 % identity). The ORF1a-1b frameshift region of 16244B had 98 % nucleotide identity with LV. Consistent with previous reports for North American isolates, the six structural proteins encoded were 58 to 79 % identical to LV proteins. The 3h NCR (150 nucleotides) was 76 % identical between isolates. These genomic differences confirm the presence of distinct North American and European PRRSV genotypes.

Characterization of Emerging European-Like Porcine Reproductive and Respiratory Syndrome Virus Isolates in the United States

“…A chymotrypsin-like (3C-like) cysteine protease domain resides at the N-terminal end of NSP2 (16). NSP2 has been shown to be variable in length among sequenced isolates of arteriviruses (1,36,39,61). PRRSV type 1 strain LV NSP2 is 861 aa in length while type 2 strains have an additional 100 aa or more, and lactate dehydrogenase-elevating virus and EAV encode NSP2 proteins which are 733 and 401 aa in length, respectively (1,20,36,82,85).…”

“…NSP2 has been shown to be variable in length among sequenced isolates of arteriviruses (1,36,39,61). PRRSV type 1 strain LV NSP2 is 861 aa in length while type 2 strains have an additional 100 aa or more, and lactate dehydrogenase-elevating virus and EAV encode NSP2 proteins which are 733 and 401 aa in length, respectively (1,20,36,82,85). Snijder et al (66) found that the NSP2 protein of EAV was involved in proteolysis of replicase precursors and membrane association of the virus replication complex, but no confirming work has been reported for other arteriviruses.…”

Evidence for the Localization of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Antigen and RNA in Ovarian Follicles in Gilts

“…The strain used for challenge was PRRSV 16244B, which was isolated in February 1997 from a case of porcine reproductive failure in Johnson County, Nebraska. 1 The inoculum was prepared after three passages in MARC-145 cells. Six gilts were inoculated intranasally with 1 ml of PRRSV (me-dian tissue culture infective dose ϭ 10 7 /ml), which was delivered in two aliquots of 0.5 ml per nostril.…”

Porcine Reproductive and Respiratory Syndrome Virus, Thailand, 2010–2011

“…The genotypes have a similar genomic organization, and 10 open reading frames (ORFs) have been identifi ed (1)(2)(3). Nonstructural protein 2 (Nsp2) and ORF5 are the most variable regions (4,5), coding for replicase protein and neutralizing epitope, respectively.…”