A counterdefensive strategy of plant viruses: suppression of posttranscriptional gene silencing

Cell. 1998 Nov 13;95(4):461-70. doi: 10.1016/s0092-8674(00)81614-1.


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

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cysteine Endopeptidases / physiology
  • DNA, Recombinant / genetics
  • DNA, Recombinant / metabolism
  • DNA, Viral / genetics
  • DNA, Viral / metabolism
  • Gene Expression Regulation, Viral* / physiology
  • Genes, Plant
  • Genes, Suppressor
  • Glucuronidase / genetics
  • Glucuronidase / metabolism
  • Green Fluorescent Proteins
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Models, Biological
  • Plant Diseases / genetics
  • Plant Diseases / virology
  • Plant Viruses / genetics*
  • Plant Viruses / metabolism
  • Plants, Genetically Modified
  • Plants, Toxic*
  • RNA Processing, Post-Transcriptional / physiology
  • Tobacco / metabolism
  • Tobacco / virology*
  • Viral Proteins / physiology


  • DNA, Recombinant
  • DNA, Viral
  • Luminescent Proteins
  • Viral Proteins
  • Green Fluorescent Proteins
  • Glucuronidase
  • Cysteine Endopeptidases
  • HC-Pro protein, potyvirus