title: Catabolite-repressor-like protein regulates the expression of a gene under the control of the Escherichia coli lac promoter in the plant pathogen Xanthomonas campestris pv. campestris.
abstract: Xanthomonas campestris pv. campestris, the causal agent of black-rot disease of cruciferous plants, and an important industrial microbe, was able to express the Escherichia coli beta-glucuronidase reporter gene (uidA) when fused to the E. coli lactose operon promoter on a wide-host-range plasmid vector. The gene fusion is expressed constitutively at high levels in both complex and defined media using a wide range of carbon sources, and is not repressible by glucose or inducible by the gratuitous lac inducer isopropyl beta-D-thiogalactoside. An X. campestris campestris strain with a lesion in the clp (catabolite-repressor-like protein) locus, and containing the placluidA fusion, was tested for beta-glucuronidase activity. We found that the expression of the placluidA fusion gene is dependent on the presence of catabolite-repressor-like protein, with an approximately 75% reduction of expression in the clp -deficient mutant.
authors.affiliation: Sainsbury Laboratory, John Innes Centre, Norwich, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Soby
authors.forename: M J
authors.initials: MJ
authors.lastname: Daniels
mesh_terms: D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D005947:Glucose / Q000494:pharmacology; D005966:Glucuronidase / Q000235:genetics* / Q000378:metabolism*; D007763:Lac Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics; D013862:Thiogalactosides / Q000494:pharmacology; D016959:Xanthomonas campestris / Q000235:genetics*
chemical_list: D012097:Repressor Proteins; D013862:Thiogalactosides; D005966:Glucuronidase; D005947:Glucose