Overexpression of virD1 and virD2 genes in Agrobacterium tumefaciens enhances T-complex formation and plant transformation.
The VirD1 and VirD2 proteins encoded by an inducible locus of the virulence (vir) region of the Agrobacterium tumefaciens Ti plasmid are required for site-specific nicking at T-DNA border sites. We have determined the nucleotide sequence of a 3.6-kilobase-pair fragment carrying the virD locus from nopaline Ti plasmid pTiC58. In contrast to the previous report (Hagiya et al., Proc. Natl. Acad. Sci. USA 82:2669-2673, 1985), we found that the first three open reading frames were capable of encoding polypeptides of 16.1, 49.7, and 21.4 kilodaltons. Deletion analysis demonstrated that the N-terminal conserved domain of VirD2 was absolutely essential for its endonuclease activity. When extra copies of the virD1 and virD2 genes were present in an A. tumefaciens strain carrying a Ti plasmid, increased amounts of T-strand and nicked molecules could be detected at early stages of vir induction. Such strains possessed the ability to transform plants with higher efficiency.
Wang
K
K
Laboratorium voor Genetica, Rijksuniversiteit Gent, Belgium.
Herrera-Estrella
A
A
Van Montagu
M
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D019868:Kanamycin Kinase; D008969:Molecular Sequence Data; D010770:Phosphotransferases / Q000235:genetics; D010944:Plants / Q000235:genetics* / Q000382:microbiology; D010957:Plasmids; D011487:Protein Conformation; D015183:Restriction Mapping; D012231:Rhizobium / Q000235:genetics* / Q000472:pathogenicity; D012689:Sequence Homology, Nucleic Acid; D014170:Transformation, Genetic; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors
D001426:Bacterial Proteins; D037521:Virulence Factors; D010770:Phosphotransferases; D019868:Kanamycin Kinase