Expression of plant protein phosphatase 2C interferes with nuclear import of the Agrobacterium T-complex protein VirD2

doi:10.1073/pnas.0300084101

Expression of plant protein phosphatase 2C interferes with nuclear import of the Agrobacterium T-complex protein VirD2

Department of Biological Sciences, Purdue University, West Lafayette, IN 47907

Edited by Brian A. Larkins, University of Arizona, Tucson, AZ, and approved January 26, 2004 (received for review January 7, 2003)

Abstract

Agrobacterium tumefaciens transfers DNA to plant cells as a single-stranded DNA molecule (the T-strand) covalently linked to VirD2 protein. VirD2 contains nuclear localization signal sequences that presumably help direct the T-strand to the plant nucleus. We identified a tomato cDNA clone, DIG3, that encodes a protein that interacts with the C-terminal region of VirD2. DIG3 encodes an enzymatically active type 2C serine/threonine protein phosphatase. Overexpression of DIG3 in tobacco BY-2 protoplasts inhibited nuclear import of a β-glucuronidase-VirD2 nuclear localization signal fusion protein. Thus, DIG3 may be involved in nuclear import of the VirD2 protein and, consequently, the VirD2/transferred DNA complex.

Footnotes

↵ ‡ To whom correspondence should be addressed. E-mail: gelvin{at}bilbo.bio.purdue.edu.
↵ * Present address: Pioneer Hi-Bred International, Incorporated, 7300 NW 62nd Avenue, Johnston, IA 50131.
↵ † Present address: School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642.
This paper was submitted directly (Track II) to the PNAS office.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AY534757).
Abbreviations: NLS, nuclear localization signal; T-DNA, transferred DNA; Ti, tumor-inducing; PP2C, type 2C serine/threonine protein phosphatase; GUS, β-glucuronidase; CM, conditioned media.