Artikel
Molecular clock analysis of bovine coronaviruses and human coronavirus OC43 suggests a relatively recent zoonotic transmission event
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Veröffentlicht: | 26. Mai 2004 |
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Gliederung
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Coronaviruses are a diverse group of large enveloped, positive-stranded RNA viruses that cause respiratory and enteric diseases in humans and animals. Based on genomic similarities, coronaviruses are classified in three groups. Two group 2 coronaviruses, human coronavirus OC43 (HCoV-OC43) and bovine coronavirus (BCoV), show remarkable antigenic and genetic similarities. The complete nucleotide sequence of different BCoV strains is known, but only fragments of the HCoV-OC43 genome had previously been determined. We report the complete HCoV-OC43 sequence (30.738 nucleotides) and the comparative characterization and evolutionary relationship of the BCoV/HCoV-OC43 pair. An HCoV-OC43 strain (VR759) was obtained from the American Type Culture Collection (ATCC) and propagated in a human rhabdomyosarcoma (RD) cell line. A set of overlapping RT-PCR products encompassing the entire genome was generated and sequenced. Oligonucleotide primers were designed in regions conserved between BCoV and mouse hepatitis virus genomes. Multiple sequence alignments were conducted and phylogenetic and molecular evolutionary analyses were performed. The entire HCoV-OC43 sequence was deposited in GenBank under accession number AY391777. Molecular clock analysis of BCoV and HCoV-OC43 suggests a relatively recent zoonotic transmission event and dates the most recent common ancestor to 1890 with a confidence interval from 1860 to 1910. An evolutionary rate was estimated in the order of 4 x 10-4 nucleotide changes per site per year. This is the first animal/human zoonotic pair of coronaviruses that can be analyzed in order to gain insights in the processes of adaptation of a non-human coronavirus to a human host.