Disease relevance of virE1

• Activities of virE1 and the VirE1 secretion chaperone in export of the multifunctional VirE2 effector via an Agrobacterium type IV secretion pathway [1].
• Two open reading frames designated virE1 and virE2 code for polypeptides of 7 and 60 kilodaltons (kDa), respectively, that can be visualized after expression in Escherichia coli minicells [2].

High impact information on virE1

• Overproduction of a virE-encoded gene product in Escherichia coli was achieved by construction of an operon fusion with the E. coli tryptophan (trp) operon [3].
• Characterization of the virE operon of the Agrobacterium Ti plasmid pTiA6 [4].
• Using a maxicell strain of E. coli, we have visualized two proteins encoded by virE which correspond in size to these open reading frames [4].
• Mutations in one of these loci, virE, result in a sharply attenuated virulence phenotype [4].
• Deletion of virE1 did not affect transcription but decreased translation of virE2, as shown by analysis of lacZ transcriptional and translational fusions [1].

Biological context of virE1

• We also found virE3 gene in the pRi1724 (1), but different from Ti plasmids, virE1 and virE2 that are also important for the virulence do not exist in the vir region of pRi1724 [5].
• In order to increase the efficiency of transfer of unusually large BIBAC T-DNAs, helper plasmids that carry additional copies of A. tumefaciens virulence genes virG and virE were constructed [6].
• Genetic complementation with mutant and wild-type alleles led to the identification of the virE locus at the right boundary, which was located about 6 kilobases from the left border of the segment of DNA that is transferred into the plant genome. virE is 2.0 kilobases long and encodes at least one protein of 69 kilodaltons [7].
• The role of inverted repeat (IR) sequence of the virE gene expression in Agrobacterium tumefaciens pTiA6 [8].
• To study how the IR sequence of the virE promoter plays a role in virE gene expression, various mutants were constructed by base substitution and deletion in the virE promoter region [8].

Associations of virE1 with chemical compounds

• Scutellum-derived calli, cultured for 25 days on medium containing 2,4-D, also induced virE to an appreciable level [9].
• On the octopine Ti plasmids from A. tumefaciens the virF gene is located between the virE locus and the left border of the T-region [10].
• These results demonstrate that when the putative -35 sequence of virE promoter is replaced with the consensus -35 sequence, the virE gene can be expressed independently without the binding of VirG protein to the vir-box and/or the induction of acetosyringone [11].

Regulatory relationships of virE1

• By contrast, PvirE or Plac promoter constructs yielded functional VirE2 only if virE1 was coexpressed with virE2 [12].

Other interactions of virE1

• The VirE3 protein is translated from a polycistronic mRNA containing the virE1, virE2 and virE3 genes, in Agrobacterium [13].

Analytical, diagnostic and therapeutic context of virE1

• A putative VirE1-VirE2 complex with a molecular mass of about 70 to 80 kDa was detected by gel filtration chromatography of extracts from wild-type cells, whereas higher-order VirE2 complexes or aggregates were detected in extracts from a virE1 mutant [1].

References