Paralogs of Genes Encoding Metal Resistance Proteins in Cupriavidus metallidurans Strain CH34Nies D.H. · Rehbein G. · Hoffmann T. · Baumann C. · Grosse C.
Institut für Mikrobiologie, Halle, Germany
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.
© 2006 S. Karger AG, Basel
Dietrich H. Nies
Institut für Mikrobiologie
DE–06099 Halle (Germany)
Tel. +49 345 552 6352, Fax +49 345 552 7010, E-Mail firstname.lastname@example.org
Number of Print Pages : 12
Number of Figures : 2, Number of Tables : 5, Number of References : 46
Journal of Molecular Microbiology and Biotechnology
Vol. 11, No. 1-2, Year 2006 (Cover Date: July 2006)
Journal Editor: Saier, M.H., Jr. (La Jolla, Calif.)
ISSN: 1464–1801 (print), 1660–2412 (Online)
For additional information: http://www.karger.com/MMB