An Agrobacterium VirE2 channel for transferred-DNA transport into plant cells

Proceedings of the National Academy of Sciences    98 (2) 16jan01

Fabrice Dumas^{*, #, +} , Myriam Duckely^#,§, Pawel Pelczar^§, Patrick Van Gelder^*, and Barbara Hohn^§

^* Department of Structural Biology, Biozentrum, Klingelbergstrasse 50, CH-4056 Basel, Switzerland; and ^§ Friedrich Miescher Institut, P.O. Box 2543, CH-4002 Basel, Switzerland

Communicated by Gottfried Schatz, University of Basel, Basel, Switzerland, October 9, 2000 (received for review August 28, 2000)

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.

^# F.D. and M.D. contributed equally to this work.

+ To whom correspondence should be addressed. E-mail: fabricedumas@yahoo.fr.

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