title: Paralogs of genes encoding metal resistance proteins in Cupriavidus metallidurans strain CH34.
abstract: Cupriavidus (Wautersia, Ralstonia, Alcaligenes) metallidurans strain CH34is a well-studied example of a metal-resistant proteobacterium. Genome sequence analysis revealed the presence of a variety of paralogs of proteins that were previously shown to be involved in heavy metal resistance. Which advantage has C. metallidurans in maintaining all these paralogs during evolution? Paralogs investigated belong to the families RND (resistance nodulation cell division) or CHR (chromate resistance). The respective genes were localized by PCR either on one of the two native megaplasmids pMOL28 and pMOL30 of strain CH34, or on its chromosomal DNA. Gene expression was studied by real-time reverse transcriptase PCR and by reporter gene constructs. Genes found to be inducible were disrupted and their contribution to metal resistance measured. When two or three highly related genes were present, usually one was inducible by heavy metals while the other one or two were silent or constitutively expressed. This suggests that C. metallidurans CH34 carries a variety of no longer or not yet used genes that might serve as surplus material for further developments, an advantage that may compensate for the costs of maintaining these genes during evolution.
authors.affiliation: Institut fur Mikrobiologie, Halle, Germany. d.nies@mikrobiologie.uni-halle.de
authors.forename: Dietrich H
authors.initials: DH
authors.lastname: Nies
authors.forename: Grit
authors.initials: G
authors.lastname: Rehbein
authors.forename: Toni
authors.initials: T
authors.lastname: Hoffmann
authors.forename: Cindy
authors.initials: C
authors.lastname: Baumann
authors.forename: Cornelia
authors.initials: C
authors.lastname: Grosse
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D042521:Burkholderiaceae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002412:Cations; D002876:Chromosomes, Bacterial; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D019216:Metals, Heavy / Q000494:pharmacology*; D010957:Plasmids
chemical_list: D001426:Bacterial Proteins; D002412:Cations; D019216:Metals, Heavy