Role of a viral membrane polypeptide in strand-specific initiation of poliovirus RNA synthesis.
A molecular genetic analysis has been combined with an in vitro biochemical approach to define the functional interactions required for nucleotidyl protein formation during poliovirus RNA synthesis. A site-directed lesion into the hydrophobic domain of a viral membrane protein produced a mutant virus that is defective in RNA synthesis at 39 degrees C. The phenotypic expression of this lesion affects initiation of RNA synthesis, in vitro uridylylation of the genome-linked protein (VPg), and the in vivo synthesis of plus-strand viral RNAs. Our results support a model that employs a viral membrane protein as carrier for VPg in the initiation of plus-strand RNA synthesis. Our data also suggest that a separate mechanism could be used in the initiation of minus-strand RNA synthesis, thereby providing a means for strand-specific regulation of picornavirus RNA replication.
Giachetti
C
C
Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine 92717.
Semler
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BL
D000595:Amino Acid Sequence; D004279:DNA, Viral; D015967:Gene Expression Regulation, Viral; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D017955:Poliovirus / Q000235:genetics*; D012367:RNA, Viral / Q000096:biosynthesis*; D013696:Temperature; D014759:Viral Envelope Proteins / Q000378:metabolism*
D004279:DNA, Viral; D012367:RNA, Viral; D014759:Viral Envelope Proteins