Translation of the minor capsid protein of a calicivirus is initiated by a novel termination-dependent reinitiation mechanism.
Caliciviruses represent a family of positive strand RNA viruses responsible for a variety of syndromes in man and animals. VP10, a minor structural protein of the calicivirus rabbit hemorrhagic disease virus, is encoded in the small 3'-terminal open reading frame (ORF) 2 and is translated with an efficiency of approximately 20% of the preceding ORF1. The presence of the ORF1 termination codon is crucial for VP10 expression. Translation of VP10 starts at an AUG codon located at positions -5 to -3 of the ORF1 termination codon. However, VP10 was also expressed in the absence of an AUG initiation codon. The majority of ORF1 could be deleted or replaced by different sequences without significant influence on VP10 expression as long as translation terminated at the given position. The RNA sequence of the 3'-terminal 84 nucleotides of ORF1 but not the encoded peptide was found to be crucial for VP10 expression. In contrast, nearly the entire ORF2 could be replaced by a foreign sequence without abrogation of its translation. Accordingly, VP10 is expressed in a translation termination/reinitiation process that is particular because it is independent of an AUG translational start codon and requires the presence of a sequence element upstream of the initiation site.
Meyers
Gregor
G
Department of Immunology, Federal Research Centre for Virus Diseases of Animals, D-72001 Tübingen, Germany. gregor.meyers@tue.bfav.de
D001483:Base Sequence; D015152:Blotting, Northern; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism*; D002460:Cell Line; D003062:Codon; D018387:Codon, Initiator; D018388:Codon, Terminator; D004151:Dipeptides; D004591:Electrophoresis, Polyacrylamide Gel; D016368:Frameshift Mutation; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012328:RNA Viruses / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
D003062:Codon; D018387:Codon, Initiator; D018388:Codon, Terminator; D004151:Dipeptides; D012333:RNA, Messenger; D011994:Recombinant Proteins; C068249:N-(3-ethoxycarbonyloxirane-2-carbonyl)-isoleucyl-proline; D012313:RNA