Disease relevance of virB1

• Characterization of the virB operon from an Agrobacterium tumefaciens Ti plasmid [1].
• The codon usage of the predicted virB genes is very similar to the other pTiA6 vir genes and is much less biased than Escherichia coli [1].
• Intracellular induction of the Bartonella henselae virB operon by human endothelial cells [2].

High impact information on virB1

• Such transfer is absolutely dependent on induction of vir genes and a functional virB operon [3].
• Because the Ti plasmid virB gene products are hypothesized to form a membrane-localized T-DNA transport apparatus, we investigated whether specific virB genes were needed for RSF1010 transfer [4].
• We report here the nucleotide sequence of the largest vir operon, virB, from the Ti plasmid pTiA6NC [1].
• Delineation of the regulatory region sequences of Agrobacterium tumefaciens virB operon [5].
• Alteration of the position of this sequence relative to the promoter region sequences had a drastic negative effect on virB expression [5].

Chemical compound and disease context of virB1

• The complete nucleotide sequence of the virB locus, from the octopine Ti plasmid of Agrobacterium tumefaciens strain 15955, has been determined [6].

Biological context of virB1

• In the large virB-operon (9600 nucleotides) we have identified eleven open reading frames, designated virB1 to virB11 [6].
• A virGN54D mutant gene of M. loti caused constitutive expression of lacZ reporter gene fusions to virB1, virD4, msi059, and msi061 [7].
• Analysis of deletion mutants, constructed by exonuclease Bal31 digestion, showed that 68 residues upstream of the virB transcription initiation site was necessary for its expression [5].
• Mutational analysis of a previously described type IV secretion system displaying homology to the virB locus of Agrobacterium tumefaciens provided the first example of an essential pathogenicity locus in Bartonella [8].
• The processes of transgene integration and transgene expression were suppressed when Agrobacteria contained mutated virA, virB or virG genes, suggesting that Agrobacterium transforms sea urchin cells by a mechanism similar to that which mediates T-DNA transfer to plants [9].

Anatomical context of virB1

• The virB operon on pRiA4 has been sequenced and found to be composed of 11 genes, virB1 to virB11, whose products mostly appear to be associated with the cell membrane [10].

Associations of virB1 with chemical compounds

• We show that AcvB shows 50% identity with the product of an open reading frame, designated virJ, that is found between the virA and virB genes in the octopine-type Ti plasmid pTiA6 [11].
• Finally, the lac promoter was used to express the native virG gene in strains containing a virB::lacZ translational fusion. virB expression in this strain depended on addition of IPTG as well as the vir gene inducer acetosyringone [12].

References