Allende R, Lewis T L, Lu Z, Rock D L, Kutish G F, Ali A, Doster A R, Osorio F A
J Gen Virol. 1999 Feb;80 ( Pt 2):307-315. doi: 10.1099/0022-1317-80-2-307.
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 63.4% nucleotide identity. The 189 nucleotide 5' 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 5'-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 ORF 1a-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 3' NCR (150 nucleotides) was 76% identical between isolates. These genomic differences confirm the presence of distinct North American and European PRRSV genotypes.
虽然猪繁殖与呼吸综合征病毒（PRRSV）的北美和欧洲血清型已得到确认，但只有欧洲莱利斯塔德毒株（LV）的基因组被完全测序。在此，对致病性北美PRRSV分离株16244B的基因组进行了测序，并与LV进行了比较。16244B的基因组结构与LV相同，但核苷酸同一性仅为63.4%。16244B的189个核苷酸的5'非编码区（NCR）与LV的NCR不同，仅在开放阅读框（ORF）1a上游紧邻的43个碱基区域具有良好的保守性（83%）。在编码ORF1a多聚蛋白非结构部分的区域发现了主要差异，在编码的六种非结构蛋白（Nsps）的2503个残基上，氨基酸同一性仅为47%。被认为具有种属特异性功能的Nsp2差异最大，与LV的氨基酸同一性仅为32%，并且在中央区域含有120个额外的氨基酸。由ORF1b的5'近端和中央区域编码的Nsps氨基酸同一性为66%至75%；然而，羧基末端蛋白CP4不同（同一性为42%）。16244B的ORF 1a-1b移码区域与LV的核苷酸同一性为98%。与先前关于北美分离株的报道一致，编码的六种结构蛋白与LV蛋白的同一性为58%至79%。分离株之间的3' NCR（150个核苷酸）同一性为76%。这些基因组差异证实了北美和欧洲PRRSV基因型的存在。
