1887

Abstract

The gene encoding the membrane (M) protein of the OC43 strain of human coronavirus (HCV-OC43) was amplified by a reverse transcription-polymerase chain reaction of viral RNA with HCV-OC43- and bovine coronavirus (BCV)-specific primers. The nucleotide sequence of the cloned 1.5 kb fragment revealed an open reading frame (ORF) of 690 nucleotides which was identified as the M protein gene from its homology to BCV. This ORF encodes a protein of 230 amino acids with an of 26416. The gene is preceded by the motif UCCAAAC, analogous to the consensus coronavirus transcription initiation sequence. The M protein of HCV-OC43 shows features typical of all coronavirus M proteins studied: a hydrophilic, presumably external N terminus including about 10% of the protein, and a potential -glycosylation site followed by three major hydrophobic transmembrane domains. The amino acid sequence of the M protein of HCV-OC43 has 94% identity with that of the Mebus strain of BCV, and also contains six potential -glycosylation sites in the exposed N-terminal domain. Indeed, the glycosylation of the M protein was not inhibited in the presence of tunicamycin, which is indicative of -glycosylation, as previously reported for BCV and murine hepatitis virus. Virions released from tunicamycin-treated cells contained the M glycoprotein but were devoid of both peplomer (S) and haemagglutinin-esterase (HE) proteins. Thus, inhibition of the -glycosylation of the S and HE structural proteins prevented their incorporation into progeny virions, an indication that they are dispensable for virion morphogenesis, unlike the M protein.

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/content/journal/jgv/10.1099/0022-1317-73-10-2731
1992-10-01
2019-11-20
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http://instance.metastore.ingenta.com/content/journal/jgv/10.1099/0022-1317-73-10-2731
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