Disease relevance of virC1

• The Agrobacterium tumefaciens virC1 gene product binds to overdrive, a T-DNA transfer enhancer [1].
• We report here the purification of the VirC1 protein from cells of Escherichia coli harboring a plasmid containing the coding sequences of the virC locus of the octopine Ti plasmid [1].
• In contrast, agroinfection of the control host Brassica rapa with cauliflower mosaic virus was less dependent on the virC gene products [2].
• Agroinfection of Z. mays with maize streak virus using strains of A. tumefaciens carrying mutations in the pTiC58 virulence region showed an almost absolute dependence on the products of the bacterial virC genes [2].

High impact information on virC1

• As virC mutants in the octopine-type plasmid pTiB6 are invariably avirulent in tests on various plant species, this gene seems to be essential for virulence and we are studying it in detail [3].
• Full expression of virC and virD of octopine and nopaline Ti plasmids is also obtained by a mutation in the ros gene of the Agrobacterium tumefaciens chromosome [4].
• Nucleotide sequence analysis of the regions flanking the insertions suggests that RosR regulates genes of diverse function, including those involved in polysaccharide production and in carbohydrate metabolism and those in a region containing sequence similarity to virC1 and virD3 from Agrobacterium tumefaciens [5].
• The levels of transient expression of the gusA gene in leaf discs infected with several strains or vir mutants correlated well with their virulence phenotype, except for virC mutants [6].
• It was found that the location of the T-DNA in the Agrobacterium genome affected the T-DNA transfer rate especially in virC mutants [6].

Biological context of virC1

• Molecular characterization of the virC genes of the Ti plasmid [7].
• Recent results from our laboratory have suggested that the virC operon which enhances T-DNA processing probably does so because the VirC1 protein interacts with overdrive (N. Toro, A. Datta, M. Yanofsky, and E. W. Nester, Proc. Natl. Acad. Sci. USA 85:8558-8562, 1988) [1].
• The homology between virC genes of octopine- and nopaline-type Ti plasmids thus includes a conservation of genetic regulatory control mechanisms as well as considerable conservation of the primary structure of the protein products [7].

Associations of virC1 with chemical compounds

• The virC (formerly bak) complementation group of the nopaline-type Ti plasmid pTiC58 encodes two proteins, VirC1 and VirC2 [7].

Regulatory relationships of virC1

• In both cases, virC was expressed constitutively in the Agrobacterium tumefaciens ros mutant [7].

Other interactions of virC1

• Mutations in virC resulted in attenuated virulence on all hosts tested, the severity of attenuation varying markedly depending on the type of plant inoculated [7].

References