Characterization of the Nonstructural and Spike Proteins of the Human Respiratory Coronavirus OC43: Comparison with Bovine Enteric Coronavirus [chapter]

Samir Mounir, Patrick Labonté, Pierre J. Talbot
1994 Advances in Experimental Medicine and Biology  
The nucleotide sequence of the region between the spike (S) and the membrane (M) protein genes, and sequences of the Sand ns2 genes of the OC43 strain of human coronavirus (HCY-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
more » ... . Sequence comparison between HCY-OC43 and the antigenically related bovine coronavirus (BCY) revealed more sequence divergence in the putative bulbous part of the S protein (SI) than in the stem region (S2). The cysteine residues near the transmembrane domain and the internal predicted protease cleavage site are conserved in the HCY-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 BCY genes. In vitro translation analyses demonstrated that the HCY-OC43 9.5-kDa protein, like its BCY counterpart, is poorly translated when situated downstream 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 BCY are absent in HCY-OC43, indicating that they are not essential for viral replication in HRT-18 cells. Coronaviruses.
doi:10.1007/978-1-4615-2996-5_10 fatcat:kns63plw5ne7fmjvazrcz3hl64