The P30 movement protein of tobacco mosaic virus is a single-strand nucleic acid binding protein

Cell. 1990 Feb 23;60(4):637-47. doi: 10.1016/0092-8674(90)90667-4.


The P30 protein of tobacco mosaic virus (TMV) is required for cell to cell movement of viral RNA, which presumably occurs through plant intercellular connections, the plasmodesmata. The mechanism by which P30 mediates transfer of TMV RNA molecules through plasmodesmata channels is unknown. We have identified P30 as an RNA and single-stranded (ss) DNA binding protein. Binding of purified P30 to ss nucleic acids is strong, highly cooperative, and sequence nonspecific with a minimal binding site of 4-7 nucleotides per P30 monomer. In-frame deletions across P30 were used to localize the ss nucleic acid binding domain to within amino acid residues 65-86 of the protein. We propose that binding of P30 to TMV RNA creates an unfolded protein-RNA complex that functions as an intermediate in virus cell to cell movement through plasmodesmata.

Publication types

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

MeSH terms

  • Chromosome Deletion
  • Cloning, Molecular
  • DNA-Binding Proteins / genetics*
  • DNA-Directed RNA Polymerases / metabolism
  • Kinetics
  • Molecular Weight
  • Mutation
  • Oligonucleotide Probes
  • Polymerase Chain Reaction
  • RNA Probes
  • RNA, Viral / metabolism*
  • Restriction Mapping
  • T-Phages / enzymology
  • Tobacco Mosaic Virus / genetics*
  • Tobacco Mosaic Virus / physiology
  • Ultraviolet Rays
  • Viral Proteins / genetics
  • Viral Proteins / isolation & purification
  • Viral Proteins / metabolism*


  • DNA-Binding Proteins
  • Oligonucleotide Probes
  • RNA Probes
  • RNA, Viral
  • Viral Proteins
  • DNA-Directed RNA Polymerases