AGROBACTERIUM VIRE2 PROTEINS CAN FORM A COMPLEX WITH T-STRANDS IN THEPLANT CYTOPLASM

Wild-type VirE2 and VirD2 proteins from Agrobacterium tumefaciens cont ain nuclear targeting sequences (MLS) that are likely involved in dire cting transferred T strands to the plant nucleus. An A. tumefaciens vi rE2 virD2 Delta NLS double mutant was able to form tumors on VirE2-pro ducing transgenic tobacco but not on wild-type tobacco. Because this m utant bacterial strain contains no known T-strand nuclear targeting si gnal, the data indicate that wild-type VirE2 proteins produced by the plant can interact with the T strands in the plant cytoplasm and direc t them to the nucleus.