P1/HC-Pro, a viral suppressor of RNA silencing, interferes with Arabidopsis development and miRNA unction

Dev Cell. 2003 Feb;4(2):205-17. doi: 10.1016/s1534-5807(03)00025-x.


The molecular basis for virus-induced disease in plants has been a long-standing mystery. Infection of Arabidopsis by Turnip mosaic virus (TuMV) induces a number of developmental defects in vegetative and reproductive organs. We found that these defects, many of which resemble those in miRNA-deficient dicer-like1 (dcl1) mutants, were due to the TuMV-encoded RNA-silencing suppressor, P1/HC-Pro. Suppression of RNA silencing is a counterdefensive mechanism that enables systemic infection by TuMV. The suppressor interfered with the activity of miR171 (also known as miRNA39), which directs cleavage of several mRNAs coding for Scarecrow-like transcription factors, by inhibiting miR171-guided nucleolytic function. Out of ten other mRNAs that were validated as miRNA-guided cleavage targets, eight accumulated to elevated levels in the presence of P1/HC-Pro. The basis for TuMV- and other virus-induced disease in plants may be explained, at least partly, by interference with miRNA-controlled developmental pathways that share components with the antiviral RNA-silencing pathway.

Publication types

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

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Blotting, Northern
  • Cysteine Endopeptidases / genetics*
  • Cysteine Endopeptidases / metabolism
  • DNA Primers / chemistry
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • Immunoblotting
  • MicroRNAs / physiology*
  • Microscopy, Electron, Scanning
  • Microscopy, Polarization
  • Mutagenesis, Site-Directed
  • Plant Structures / genetics
  • Plant Structures / metabolism
  • Plant Structures / virology*
  • Plants, Genetically Modified
  • Plasmids
  • Polymerase Chain Reaction
  • RNA Interference / physiology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Tymovirus / pathogenicity*
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism


  • Arabidopsis Proteins
  • DNA Primers
  • MicroRNAs
  • RNA, Messenger
  • RNA, Plant
  • SCR protein, Arabidopsis
  • Viral Proteins
  • Cysteine Endopeptidases
  • HC-Pro protein, potyvirus