title: The combined actions of the copper-responsive repressor CsoR and copper-metallochaperone CopZ modulate CopA-mediated copper efflux in the intracellular pathogen Listeria monocytogenes.
abstract: We have characterized the csoR-copA-copZ copper resistance operon of the important human intracellular pathogen Listeria monocytogenes. Transcription of the operon is specifically induced by copper, and mutants lacking the P₁-type ATPase CopA have reduced copper tolerance and over-accumulate copper relative to wild type. The copper-responsive repressor CsoR autoregulates transcription by binding to a single 32 bp site spanning the -10 and -35 elements of the promoter. Copper co-ordination by CsoR derepresses transcription of the operon and alters CsoR:DNA complex assembly as determined by DNase I footprinting and electrophoretic mobility shift assays, with some DNA-binding capacity being retained in the presence of 2 mole equivalents of copper. Analysis of the CsoR copper sensory site demonstrated that substitution of Cys⁴² with Ala generated a CsoR variant that was unresponsive to copper. Importantly, in the absence of CopZ, copper responsiveness of csoR-copA-copZ expression is substantially increased, implying that CopZ reduces the access of CsoR to copper. Furthermore, CopZ is shown to confer copper resistance in mutants lacking copper-inducible csoR-copA-copZ expression, thus providing protection from the deleterious effects of copper within the cytoplasm.
authors.affiliation: Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M139PT, UK.
authors.forename: David
authors.initials: D
authors.lastname: Corbett
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schuler
authors.forename: Sarah
authors.initials: S
authors.lastname: Glenn
authors.forename: Peter W
authors.initials: PW
authors.lastname: Andrew
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Cavet
authors.forename: Ian S
authors.initials: IS
authors.lastname: Roberts
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000825:Animal Structures / Q000382:microbiology; D000818:Animals; D019677:Artificial Gene Fusion; D058491:Bacterial Load; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000378:metabolism; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D008088:Listeriosis / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D056511:Metallochaperones / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012376:Rodent Diseases / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D016415:Sequence Alignment; D016019:Survival Analysis; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C071263:CopA protein, Bacteria; D004269:DNA, Bacterial; D056511:Metallochaperones; D050505:Mutant Proteins; D012097:Repressor Proteins; D003300:Copper; D001616:beta-Galactosidase