Covalently bound VirD2 protein of Agrobacterium tumefaciens protects the T-DNA from exonucleolytic degradation.
We show that upon induction of Agrobacterium tumefaciens, free linear double-stranded T-DNA molecules as well as the previously described T-strands are generated from the Ti plasmid. A majority of these molecules are bound to a protein. We show that this protein is the product of the virulence gene virD2. This protein was found to be attached to the 5' terminus of processed T-DNA at the right border and to the rest of the Ti plasmid at the left border. The protein remnant after Pronase digestion rendered the right end of the double-stranded T-DNA resistant to 5'----3' exonucleolytic attack in vitro. The protein-DNA association was resistant to SDS, mercaptoethanol, mild alkali, piperidine, and hydroxylamine, indicating that it involves a covalent linkage. The possible involvement of this T-DNA-protein complex in replication, transduction to the plant, nuclear targeting, and integration into the plant nuclear DNA is discussed.
Dürrenberger
F
F
Friedrich Miescher-Institut, Basel, Switzerland.
Crameri
A
A
Hohn
B
B
Koukolíková-Nicola
Z
Z
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000302:isolation & purification / Q000378:metabolism*; D005092:Exonucleases; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009710:Nucleotide Mapping; D010957:Plasmids; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors; D005092:Exonucleases