猪呼吸道冠状病毒分离株的序列比较揭示了S、3和3-1基因的异质性。
Sequence comparison of porcine respiratory coronavirus isolates reveals heterogeneity in the S, 3, and 3-1 genes.
作者信息
Vaughn E M, Halbur P G, Paul P S
机构信息
Veterinary Medical Research Institute, Iowa State University, Ames 50011, USA.
出版信息
J Virol. 1995 May;69(5):3176-84. doi: 10.1128/JVI.69.5.3176-3184.1995.
Four new porcine respiratory coronavirus (PRCV) isolates were genetically characterized. Subgenomic mRNA patterns and the nucleotide sequences of the 5' ends of the S genes, the open reading frame (ORF) 3/3a genes, and the ORF 3-1/3b genes of these PRCV isolates were determined and compared with those of other PRCV and transmissible gastroenteritis virus (TGEV) isolates. The S, ORF 3/3a, and ORF 3-1/3b genes are under intense study because of their possible roles in determining tissue tropism and virulence. Northern (RNA) blot analysis of subgenomic mRNAs revealed that mRNA 2, which encodes for the S gene, of the PRCV isolates migrated faster than the mRNA 2 of TGEV. The PRCV isolates AR310 and LEPP produced eight subgenomic mRNA species, the same number as produced by the virulent Miller strain of TGEV. However, the PRCV isolates IA1894 and ISU-1 produced only seven subgenomic mRNA species. All four of the PRCV isolates were found to have a large in-frame deletion in the 5' end of the S gene; however, the size and location of the deletion varied. Analysis of the ORF 3/3a gene nucleotide sequences from the four PRCV isolates also showed a high degree of variability in this area. The ORF 3 gene of the PRCV isolates AR310 and LEPP was preceded by a CTAAAC leader RNA-binding site, and the ORF 3 gene was predicted to yield a protein of 72 amino acids, the same size as that of the virulent Miller strain of TGEV. The PRCV isolates AR310 and LEPP are the first PRCV isolates found to have an intact ORF 3 gene. The ORF 3a gene of the PRCV isolate IA1894 was preceded by a CTAAAC leader RNA-binding site and was predicted to yield a truncated protein of 54 amino acids due to a 23-nucleotide deletion. The CTAAAC leader RNA-binding site and ATG start codon of ORF 3 gene of the PRCV isolate ISU-1 were removed because of a 168-nucleotide deletion. Analysis of the ORF 3-1/3b gene nucleotide sequences from the four PRCV nucleotides isolates also showed variability.
对四株新的猪呼吸道冠状病毒（PRCV）分离株进行了基因特征分析。测定了这些PRCV分离株的亚基因组mRNA模式以及S基因5'端、开放阅读框（ORF）3/3a基因和ORF 3-1/3b基因的核苷酸序列，并与其他PRCV和传染性胃肠炎病毒（TGEV）分离株进行了比较。由于S、ORF 3/3a和ORF 3-1/3b基因在决定组织嗜性和毒力方面可能发挥的作用，因此对它们进行了深入研究。对亚基因组mRNA的Northern（RNA）印迹分析表明，PRCV分离株中编码S基因的mRNA 2迁移速度比TGEV的mRNA 2快。PRCV分离株AR310和LEPP产生了8种亚基因组mRNA种类，与TGEV的强毒株Miller株产生的数量相同。然而，PRCV分离株IA1894和ISU-1仅产生7种亚基因组mRNA种类。发现所有四株PRCV分离株在S基因的5'端都有一个大的框内缺失；然而，缺失的大小和位置各不相同。对四株PRCV分离株的ORF 3/3a基因核苷酸序列分析也表明该区域存在高度变异性。PRCV分离株AR310和LEPP的ORF 3基因之前有一个CTAAAC前导RNA结合位点，预测该ORF 3基因产生的蛋白质为72个氨基酸，与TGEV的强毒株Miller株大小相同。PRCV分离株AR310和LEPP是首批发现具有完整ORF 3基因的PRCV分离株。PRCV分离株IA1894的ORF 3a基因之前有一个CTAAAC前导RNA结合位点，由于23个核苷酸的缺失，预测产生一个截短的54个氨基酸的蛋白质。由于168个核苷酸的缺失，PRCV分离株ISU-1的ORF 3基因的CTAAAC前导RNA结合位点和ATG起始密码子被去除。对四株PRCV核苷酸分离株的ORF 3-1/3b基因核苷酸序列分析也显示出变异性。
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