title: Identification of a Salmonella ancillary copper detoxification mechanism by a comparative analysis of the genome-wide transcriptional response to copper and zinc excess.
abstract: Copper and zinc are essential metal ions, but toxic in excess. Bacteria have evolved different strategies to control their intracellular concentrations, ensuring proper supply while avoiding toxicity, including the induction of metal-specific as well as non-specific mechanisms. We compared the transcriptional profiles of Salmonella Typhimurium after exposure to either copper or zinc ions in both rich and minimal media. Besides metal-specific regulatory networks many global stress-response pathways react to an excess of either of these metal ions. Copper excess affects both zinc and iron homeostasis by inducing transcription of these metal-specific regulons. In addition to the control of zinc-specific regulons, zinc excess affects the Cpx regulon and the σ(E) envelope-stress responses. Finally, novel metal-specific upregulated genes were detected including a new copper-detoxification pathway that involves the siderophore enterobactin and the outer-membrane protein TolC. This work sheds light onto the transcriptional landscape of Salmonella after copper or zinc overload, and discloses a new mechanism of copper detoxification.
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Ocampo y Esmeralda, 2000-Rosario, Argentina.
authors.forename: Lucas B
authors.initials: LB
authors.lastname: Pontel
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Ocampo y Esmeralda, 2000-Rosario, Argentina.
authors.forename: Nadia L
authors.initials: NL
authors.lastname: Scampoli
authors.affiliation: Department of Pathology and Laboratory Medicine, University of California, Irvine, CA, USA.|Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA.
authors.forename: Steffen
authors.initials: S
authors.lastname: Porwollik
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Ocampo y Esmeralda, 2000-Rosario, Argentina.
authors.forename: Susana K
authors.initials: SK
authors.lastname: Checa
authors.affiliation: Department of Pathology and Laboratory Medicine, University of California, Irvine, CA, USA.|Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: McClelland
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario, Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Ocampo y Esmeralda, 2000-Rosario, Argentina.
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Soncini
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D016680:Genome, Bacterial; D018085:Regulon; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D015032:Zinc / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D003300:Copper; D015032:Zinc