Abstract
Posttranscriptional gene silencing (PTGS) in plants inactivates some aberrant or highly expressed RNAs in a sequence-specific manner in the cytoplasm. A silencing mechanism similar to PTGS appears to function as an adaptive antiviral response. We demonstrate that the P1/HC-Pro polyprotein encoded by tobacco etch virus functions as a suppressor of PTGS. A locus comprised of a highly expressed beta-glucuronidase (GUS) transgene was shown to exhibit PTGS. Genetic crosses and segregation analyses revealed that a P1/ HC-Pro transgene suppressed PTGS of the GUS sequence. Nuclear transcription assays indicated that the silencing suppression activity of P1/HC-Pro was at the posttranscriptional level. These data reveal that plant viruses can condition enhanced susceptibility within a host through interdiction of a potent defense response.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Cysteine Endopeptidases / physiology
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DNA, Recombinant / genetics
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DNA, Recombinant / metabolism
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DNA, Viral / genetics
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DNA, Viral / metabolism
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Gene Expression Regulation, Viral* / physiology
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Genes, Plant
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Genes, Suppressor
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Glucuronidase / genetics
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Glucuronidase / metabolism
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Green Fluorescent Proteins
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Models, Biological
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Nicotiana / metabolism
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Nicotiana / virology*
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Plant Diseases / genetics
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Plant Diseases / virology
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Plant Viruses / genetics*
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Plant Viruses / metabolism
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Plants, Genetically Modified
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Plants, Toxic*
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RNA Processing, Post-Transcriptional / physiology
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Viral Proteins / physiology
Substances
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DNA, Recombinant
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DNA, Viral
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Luminescent Proteins
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Viral Proteins
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Green Fluorescent Proteins
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Glucuronidase
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Cysteine Endopeptidases
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HC-Pro protein, potyvirus