An Agrobacterium VirE2 Channel for Transferred-DNA Transport into Plant Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS 2001-01, Vol.98 (2), p.485-490
• Main Authors: Dumas, Fabrice, Duckely, Myriam, Pelczar, Pawel, Van Gelder, Patrick, Hohn, Barbara
• Format: Article
• Language: English
• Subjects: Agrobacterium; Agrobacterium tumefaciens; Agrobacterium tumefaciens - physiology; Anions - metabolism; Arabidopsis - microbiology; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - physiology; Biological Sciences; Biological Transport; Cell Membrane Permeability; Cell membranes; Cells; Deoxyribonucleic acid; Diffusion; DNA; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; DNA, Single-Stranded - genetics; DNA, Single-Stranded - metabolism; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - physiology; Electric potential; Flowers & plants; Ion Channel Gating - physiology; Ion Channels; Ion Transport; Lipid Bilayers; Lipids; Macromolecular Substances; Membrane Lipids - metabolism; Membrane Proteins - chemistry; Membrane Proteins - physiology; Models, Biological; Molecular Chaperones - metabolism; Molecules; Nuclear Proteins - metabolism; Plant cells; Plant Proteins - metabolism; Plasmids; Plasmids - genetics; Protein Binding; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Swelling; T-DNA; Transformation, Bacterial - physiology; VirE2 protein; Virulence Factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.011477898

Transferred DNA (T-DNA) transfer from Agrobacterium tumefaciens into eukaryotic cells is the only known example of interkingdom DNA transfer. T-DNA is a single-stranded segment of Agrobacterium's tumor-inducing plasmid that enters the plant cell as a complex with the bacterial virulence proteins VirD2 and VirE2. The VirE2 protein is highly induced on contact of A. tumefaciens with a plant host and has been reported to act in late steps of transfer. One of its previously demonstrated functions is binding to the single-stranded (ss) T-DNA and protecting it from degradation. Recent experiments suggest other functions of the protein. A combination of planar lipid bilayer experiments, vesicle swelling assays, and DNA transport experiments demonstrated that VirE2 can insert itself into artificial membranes and form channels. These channels are voltage gated, anion selective, and single-stranded DNA-specific and can facilitate the efficient transport of single-stranded DNA through membranes. These experiments demonstrate a VirE2 function as a transmembrane DNA transporter, which could have applications in gene delivery systems.