The VirD2 protein of A. tumefaciens contains a C-terminal bipartite nuclear localization signal: implications for nuclear uptake of DNA in plant cells

Cell. 1992 Jan 10;68(1):109-18. doi: 10.1016/0092-8674(92)90210-4.


Here we show that the VirD2 protein of A. tumefaciens functions as a nuclear localizing protein in plant cells. The nuclear localization signal of VirD2 consists of two regions containing 4-5 basic amino acids (KRPR and RKRER), located within the C-terminal 34 amino acids. These regions conform to the KR/KXR/K motif required for numerous nuclear localized nonplant eukaryotic proteins. Each region independently directs a beta-glucuronidase reporter protein to the nucleus; however, both regions are necessary for maximum efficiency. VirD2 has been shown to be tightly bound to the 5' end of the single-stranded DNA transfer intermediate, T-strand, transferred from Agrobacterium to the plant cell genome. The present results imply that T-strand transport to the plant nucleus is mediated by the tightly attached VirD2 protein via an import pathway common to higher eukaryotes.

Publication types

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

MeSH terms

  • Agrobacterium tumefaciens / genetics
  • Agrobacterium tumefaciens / physiology*
  • Amino Acid Sequence
  • Bacterial Proteins / genetics*
  • Cell Nucleus / physiology*
  • Cells, Cultured
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Plants, Toxic*
  • Plasmids
  • Protein Sorting Signals / genetics*
  • Protoplasts / physiology
  • Sequence Homology, Nucleic Acid
  • Tobacco / microbiology*
  • Virulence Factors*


  • Bacterial Proteins
  • Protein Sorting Signals
  • Virulence Factors