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. 1987 Nov;9(6):635-45.
doi: 10.1007/BF00020539.

Molecular characterization of the virulence gene virA of the Agrobacterium tumefaciens octopine Ti plasmid

L S Melchers  1 , D V Thompson, K B Idler, S T Neuteboom, R A de Maagd, R A Schilperoort, P J Hooykaas
Affiliations

Molecular characterization of the virulence gene virA of the Agrobacterium tumefaciens octopine Ti plasmid

L S Melchers et al. Plant Mol Biol. 1987 Nov.

Abstract

The virulence loci play an essential role in tumor formation by Agrobacterium tumefaciens. Induction of vir gene expression by plant signal molecules is solely dependent on the virulence loci virA and virG. This study focused on the virA locus of the octopine type Ti plasmid pTi15955. The nucleic acid sequence of a 5.7-kilobase fragment encompassing virA was determined. Genetic analysis of this region revealed that virA contains one open reading frame coding for a protein of 91 639 daltons. Immunodetection with antibodies raised against a 35-kDa VirA fusion protein produced in E. coli identified by the VirA product in wild-type Agrobacterium cells. Moreover, it is shown that the VirA protein is located in the cytoplasmic membrane fraction of Agrobacterium. These data confirm the proposed regulatory function of VirA whereby VirA acts as a membrane sensor protein to identify plant signal molecules in the environment. The proposed sensory function of VirA strikingly resembles the function of the chemotaxis receptor proteins of E. coli.

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References

    1. J Bacteriol. 1983 Feb;153(2):878-83 - PubMed
    1. Microbiol Rev. 1986 Jun;50(2):193-225 - PubMed
    1. Science. 1985 Mar 22;227(4693):1435-41 - PubMed
    1. Nucleic Acids Res. 1986 Feb 11;14(3):1355-64 - PubMed
    1. Nature. 1984 Dec 6-12;312(5994):564-6 - PubMed