Disease relevance of virD1

• The endonuclease function was further localized to the 5' end of this operon by demonstrating that cleavage does not occur in virD mutant strains of Agrobacterium and that the 5' end of the virD operon is sufficient to direct cleavage in E. coli [1].
• The virD operon of Agrobacterium tumefaciens encodes a site-specific endonuclease [1].

High impact information on virD1

• Furthermore, the two 5' cistrons of virD are required for both border nicks and T-strands, suggesting that these genes encode the border endonuclease, and that T-strand production is dependent on border nicks [2].
• The approach is to deliver into plant protoplasts by direct gene transfer the Agrobacterium virulence genes virD1 and virD2 with or without virE2, together with a target plasmid containing a gene of interest flanked by Agrobacterium T-DNA border repeat sequences of 25 bp [3].
• S1-nuclease analysis, in vitro transcription, and DNase I protection experiments with A. tumefaciens RNA polymerase revealed virD promoters tandemly arranged, both of which are functional in the Ros mutant, while only one is functional in the presence of acetosyringone [4].
• A search of the vir genes involved in controlling this biphasic reaction in induced A. tumefaciens cells revealed that virA on the Ti plasmid is involved and that neither virB nor virD genes are needed for this reaction [5].
• In the virC and virD promoter region, this binding site is within a cluster of vir box consensus sequences in which the VirG protein binds [6].

Chemical compound and disease context of virD1

• Cells of E. coli harbored two compatible plasmids, one containing coding sequences overlapping the virC and virD regions of the nopaline Ti plasmid, and a second plasmid containing a T-DNA region [7].

Biological context of virD1

• The virD locus of Agrobacterium tumefaciens Ti plasmid pTiA6 was sequenced [8].

Anatomical context of virD1

• Genetic analysis of the virD operon of Agrobacterium tumefaciens: a search for functions involved in transport of T-DNA into the plant cell nucleus and in T-DNA integration [9].

Associations of virD1 with chemical compounds

• When induced with isopropyl-beta-D-thiogalactopyranoside, the virD gene products exhibited double-stranded T-DNA border-specific endonuclease activity [8].
• At the onset of T-DNA processing virD-encoded proteins introduce a nick in the largest of these conserved regions (12 bp) at a specific position in the bottom strand between a guanine and thymine nucleotide [2, 33] [10].

References