Complete genomic sequence of human coronavirus OC43: molecular clock analysis suggests a relatively recent zoonotic coronavirus transmission event.
Coronaviruses are enveloped, positive-stranded RNA viruses with a genome of approximately 30 kb. Based on genetic similarities, coronaviruses are classified into three groups. Two group 2 coronaviruses, human coronavirus OC43 (HCoV-OC43) and bovine coronavirus (BCoV), show remarkable antigenic and genetic similarities. In this study, we report the first complete genome sequence (30,738 nucleotides) of the prototype HCoV-OC43 strain (ATCC VR759). Complete genome and open reading frame (ORF) analyses were performed in comparison to the BCoV genome. In the region between the spike and membrane protein genes, a 290-nucleotide deletion is present, corresponding to the absence of BCoV ORFs ns4.9 and ns4.8. Nucleotide and amino acid similarity percentages were determined for the major HCoV-OC43 ORFs and for those of other group 2 coronaviruses. The highest degree of similarity is demonstrated between HCoV-OC43 and BCoV in all ORFs with the exception of the E gene. Molecular clock analysis of the spike gene sequences of BCoV and HCoV-OC43 suggests a relatively recent zoonotic transmission event and dates their most recent common ancestor to around 1890. An evolutionary rate in the order of 4 x 10(-4) nucleotide changes per site per year was estimated. This is the first animal-human zoonotic pair of coronaviruses that can be analyzed in order to gain insights into the processes of adaptation of a nonhuman coronavirus to a human host, which is important for understanding the interspecies transmission events that led to the origin of the severe acute respiratory syndrome outbreak.
Vijgen
Leen
L
Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Minderbroedersstraat 10, BE-3000 Leuven, Belgium.
Keyaerts
Els
E
Moës
Elien
E
Thoelen
Inge
I
Wollants
Elke
E
Lemey
Philippe
P
Vandamme
Anne-Mieke
AM
Van Ranst
Marc
M
D000818:Animals; D002417:Cattle; D018352:Coronavirus Infections / Q000635:transmission* / Q000821:virology; D028962:Coronavirus OC43, Human / Q000235:genetics*; D017938:Coronavirus, Bovine / Q000235:genetics; D019143:Evolution, Molecular; D016679:Genome, Viral; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000235:genetics; D015047:Zoonoses / Q000635:transmission* / Q000821:virology
D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins