title: Indications for acquisition of reductive dehalogenase genes through horizontal gene transfer by Dehalococcoides ethenogenes strain 195.
abstract: The genome of Dehalococcoides ethenogenes strain 195, an anaerobic dehalorespiring bacterium, contains 18 copies of putative reductive dehalogenase genes, including the well-characterized tceA gene, whose gene product functions as the key enzyme in the environmentally important dehalorespiration process. The genome of D. ethenogenes was analyzed using a bioinformatic tool based on the frequency of oligonucleotides. The results in the form of a genomic signature revealed several local disruptions of the host signature along the genome sequence. These fractures represent DNA segments of potentially foreign origin, so-called atypical regions, which may have been acquired by an ancestor through horizontal gene transfer. Most interestingly, 15 of the 18 reductive dehalogenase genes, including the tceA gene, were found to be located in these regions, strongly indicating the foreign nature of the dehalorespiration activity. The GC content and the presence of recombinase genes within some of these regions corroborate this hypothesis. A hierarchical classification of the atypical regions containing the reductive dehalogenase genes indicated that these regions were probably acquired by several gene transfer events.
authors.affiliation: Swiss Federal Institute of Technology Lausanne (EPFL), ENAC-Laboratory for Environmental Biotechnology, Bātiment CH-B Ecublens, CH-1015 Lausanne, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Regeard
authors.forename: Julien
authors.initials: J
authors.lastname: Maillard
authors.forename: Christine
authors.initials: C
authors.lastname: Dufraigne
authors.forename: Patrick
authors.initials: P
authors.lastname: Deschavanne
authors.forename: Christof
authors.initials: C
authors.lastname: Holliger
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001482:Base Composition; D041862:Chloroflexi / Q000201:enzymology* / Q000235:genetics*; D019295:Computational Biology; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics*; D045522:Recombinases
chemical_list: D001426:Bacterial Proteins; D045522:Recombinases; D010088:Oxidoreductases; C112990:tetrachloroethene dehalogenase