Triple gene block proteins of white clover mosaic potexvirus are required for transport

Virology. 1991 Aug;183(2):695-702. doi: 10.1016/0042-6822(91)90998-q.


The functions of the protein products encoded by a block of three overlapping genes (the triple gene block) of white clover mosaic potexvirus (WCIMV) have been determined. Mutations were introduced into each of the triple gene block open reading frames and in vitro RNA transcripts assayed in plants and protoplasts. None of the mutants was able to induce symptoms or spread in four systemic hosts and one local lesion host, but all were able to produce progeny genomic RNA, subgenomic RNA, coat protein, and virions in inoculated protoplasts, indicating that all the triple gene block proteins are involved in cell-to-cell spread. Based on observed homologies between the triple gene block proteins of the potex-, carla-, furo-, and hordeivirus groups and Nicotiana velutina mosaic virus, and the demonstrated transport function of the WCIMV and barley stripe mosaic virus triple gene block proteins, these proteins are proposed to constitute a new class of transport proteins.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport
  • Capsid / genetics
  • DNA, Viral
  • Fabaceae / microbiology
  • Genes, Viral
  • Molecular Sequence Data
  • Mosaic Viruses / genetics*
  • Mosaic Viruses / metabolism
  • Mosaic Viruses / pathogenicity
  • Mutagenesis
  • Open Reading Frames
  • Plant Diseases
  • Plants, Medicinal
  • Protein Biosynthesis
  • Protoplasts / microbiology
  • Transcription, Genetic
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism


  • DNA, Viral
  • Viral Proteins