Mounir S, Labonté P, Talbot P J
Centre de Recherche en Virologie, Institut Armand-Frappier, Université du Québec, Laval, Canada.
Adv Exp Med Biol. 1993;342:61-7. doi: 10.1007/978-1-4615-2996-5_10.
The nucleotide sequence of the region between the spike (S) and the membrane (M) protein genes, and sequences of the S and ns2 genes of the OC43 strain of human coronavirus (HCV-OC43) were determined. The ns2 gene comprises an open reading frame (ORF) encoding a putative nonstructural (ns) protein of 279 amino acids with a predicted molecular mass of 32-kDa. The S gene comprises an ORF encoding a protein of 1353 amino acid residues, with a predicted molecular weight of 149,918. Sequence comparison between HCV-OC43 and the antigenically related bovine coronavirus (BCV) revealed more sequence divergence in the putative bulbous part of the S protein (S1) than in the stem region (S2). The cysteine residues near the transmembrane domain and the internal predicted protease cleavage site are conserved in the HCV-OC43 S protein. Nucleotide sequence analysis of the region between the S and M gene loci revealed the presence of an unexpected intragenomic partial leader sequence and two ORFs encoding potential proteins of 12.9 and 9.5-kDa. These two proteins were identified as nonstructural by comparison with the homologous BCV genes. In vitro translation analyses demonstrated that the HCV-OC43 9.5-kDa protein, like its BCV counterpart, is poorly translated when situated down-stream of the 12.9-kDa ORF, but is expressed in infected cells, as shown by immunofluorescence. Interestingly, two ORFs, potentially encoding 4.9 and 4.8-kDa ns proteins in BCV are absent in HCV-OC43, indicating that they are not essential for viral replication in HRT-18 cells.
测定了人冠状病毒OC43株（HCV-OC43）刺突（S）蛋白基因和膜（M）蛋白基因之间区域的核苷酸序列，以及S基因和ns2基因的序列。ns2基因包含一个开放阅读框（ORF），编码一个推定的非结构（ns）蛋白，该蛋白由279个氨基酸组成，预测分子量为32 kDa。S基因包含一个ORF，编码一个由1353个氨基酸残基组成的蛋白，预测分子量为149,918。HCV-OC43与抗原相关的牛冠状病毒（BCV）之间的序列比较显示，S蛋白推定的球状部分（S1）比茎区域（S2）的序列差异更大。跨膜结构域附近的半胱氨酸残基和内部预测的蛋白酶切割位点在HCV-OC43 S蛋白中是保守的。S基因和M基因座之间区域的核苷酸序列分析显示存在一个意外的基因组内部分前导序列和两个编码潜在的12.9 kDa和9.5 kDa蛋白的ORF。通过与同源BCV基因比较，这两种蛋白被鉴定为非结构蛋白。体外翻译分析表明，HCV-OC43 9.5 kDa蛋白与其BCV对应物一样，当位于12.9 kDa ORF下游时翻译效率较低，但如免疫荧光所示，在感染细胞中表达。有趣的是，HCV-OC43中不存在BCV中可能编码4.9 kDa和4.8 kDa ns蛋白的两个ORF，这表明它们对于HRT-18细胞中的病毒复制不是必需的。
