Abstract
The red clover necrotic mosaic virus genome is composed of two single-stranded RNA components, RNA-1 and RNA-2. The viral capsid protein is translated from a subgenomic RNA (sgRNA) that is transcribed from genomic RNA-1. Here, a 34-nucleotide sequence in RNA-2 is shown to be required for transcription of sgRNA. Mutations that prevent base-pairing between the RNA-1 subgenomic promoter and the 34-nucleotide trans-activator prevent expression of a reporter gene. A model is proposed in which direct binding of RNA-2 to RNA-1 trans-activates sgRNA synthesis. This RNA-mediated regulation of transcription is unusual among RNA viruses, which typically rely on protein regulators.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Base Composition
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Base Sequence
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DNA, Complementary
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Gene Expression
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Genes, Reporter
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Green Fluorescent Proteins
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Luminescent Proteins / genetics
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Models, Genetic
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Molecular Sequence Data
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Mosaic Viruses / genetics*
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Mutation
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Nucleic Acid Conformation
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Promoter Regions, Genetic
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RNA, Double-Stranded / genetics
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RNA, Double-Stranded / metabolism
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RNA, Messenger / biosynthesis
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RNA, Messenger / genetics
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RNA, Viral / biosynthesis
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RNA, Viral / chemistry
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RNA, Viral / genetics*
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Sequence Alignment
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Transcriptional Activation*
Substances
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DNA, Complementary
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Luminescent Proteins
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RNA, Double-Stranded
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RNA, Messenger
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RNA, Viral
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Green Fluorescent Proteins