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Mutants of Agrobacterium VirA that activate vir gene expression in the absence of the inducer acetosyringone.
J Biol Chem. 1994 Jan 28; 269(4):2645-51.JB

Abstract

In the presence of inducer molecules produced by wounded plants, the VirA/VirG two-component positive regulatory system of Agrobacterium tumefaciens initiates transcription of virulence genes required for crown gall tumor formation. Exactly how this system enables the bacterium to respond to an environmental signal is not known, but phosphorylation of VirA and VirG plays a role. To analyze further the function of VirA, we chemically mutagenized the virA gene. Two mutants that activate vir transcription without the plant inducer acetosyringone were found; these mutants alter VirA function by distinct mechanisms. One mutant functions entirely independently of acetosyringone, whereas the activity of the second mutant is enhanced by acetosyringone. Both mutants function best at acid pH, but respond differently to specific monosaccharides that stimulate induction by wild-type VirA. Both mutant phenotypes are dominant over wild-type VirA, and both need the conserved histidine at the autophosphorylation site for strong inducer-independent vir transcription.

Authors+Show Affiliations

Department of Plant Biology, University of California, Berkeley 94720.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

8300595

Citation

McLean, B G., et al. "Mutants of Agrobacterium VirA That Activate Vir Gene Expression in the Absence of the Inducer Acetosyringone." The Journal of Biological Chemistry, vol. 269, no. 4, 1994, pp. 2645-51.
McLean BG, Greene EA, Zambryski PC. Mutants of Agrobacterium VirA that activate vir gene expression in the absence of the inducer acetosyringone. J Biol Chem. 1994;269(4):2645-51.
McLean, B. G., Greene, E. A., & Zambryski, P. C. (1994). Mutants of Agrobacterium VirA that activate vir gene expression in the absence of the inducer acetosyringone. The Journal of Biological Chemistry, 269(4), 2645-51.
McLean BG, Greene EA, Zambryski PC. Mutants of Agrobacterium VirA That Activate Vir Gene Expression in the Absence of the Inducer Acetosyringone. J Biol Chem. 1994 Jan 28;269(4):2645-51. PubMed PMID: 8300595.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mutants of Agrobacterium VirA that activate vir gene expression in the absence of the inducer acetosyringone. AU - McLean,B G, AU - Greene,E A, AU - Zambryski,P C, PY - 1994/1/28/pubmed PY - 1994/1/28/medline PY - 1994/1/28/entrez SP - 2645 EP - 51 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 269 IS - 4 N2 - In the presence of inducer molecules produced by wounded plants, the VirA/VirG two-component positive regulatory system of Agrobacterium tumefaciens initiates transcription of virulence genes required for crown gall tumor formation. Exactly how this system enables the bacterium to respond to an environmental signal is not known, but phosphorylation of VirA and VirG plays a role. To analyze further the function of VirA, we chemically mutagenized the virA gene. Two mutants that activate vir transcription without the plant inducer acetosyringone were found; these mutants alter VirA function by distinct mechanisms. One mutant functions entirely independently of acetosyringone, whereas the activity of the second mutant is enhanced by acetosyringone. Both mutants function best at acid pH, but respond differently to specific monosaccharides that stimulate induction by wild-type VirA. Both mutant phenotypes are dominant over wild-type VirA, and both need the conserved histidine at the autophosphorylation site for strong inducer-independent vir transcription. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/8300595/Mutants_of_Agrobacterium_VirA_that_activate_vir_gene_expression_in_the_absence_of_the_inducer_acetosyringone_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=8300595 DB - PRIME DP - Unbound Medicine ER -