title: Comparative analysis of superintegrons: engineering extensive genetic diversity in the Vibrionaceae.
abstract: Integrons are natural tools for bacterial evolution and innovation. Their involvement in the capture and dissemination of antibiotic-resistance genes among Gram-negative bacteria is well documented. Recently, massive ancestral versions, the superintegrons (SIs), were discovered in the genomes of diverse proteobacterial species. SI gene cassettes with an identifiable activity encode proteins related to simple adaptive functions, including resistance, virulence, and metabolic activities, and their recruitment was interpreted as providing the host with an adaptive advantage. Here, we present extensive comparative analysis of SIs identified among the Vibrionaceae. Each was at least 100 kb in size, reaffirming the participation of SIs in the genome plasticity and heterogeneity of these species. Phylogenetic and localization data supported the sedentary nature of the functional integron platform and its coevolution with the host genome. Conversely, comparative analysis of the SI cassettes was indicative of both a wide range of origin for the entrapped genes and of an active cassette assembly process in these bacterial species. The signature attC sites of each species displayed conserved structural characteristics indicating that symmetry rather than sequence was important in the recognition of such a varied collection of target recombination sequences by a single site-specific recombinase. Our discovery of various addiction module cassettes within each of the different SIs indicates a possible role for them in the overall stability of large integron cassette arrays.
authors.affiliation: Département de Microbiologie Fondamentale et Médicale, Institut Pasteur, 75724 Paris, France.
authors.forename: Dean A
authors.initials: DA
authors.lastname: Rowe-Magnus
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Guerout
authors.forename: Latefa
authors.initials: L
authors.lastname: Biskri
authors.forename: Philippe
authors.initials: P
authors.lastname: Bouige
authors.forename: Didier
authors.initials: D
authors.lastname: Mazel
mesh_terms: D001287:Attachment Sites, Microbiological / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods; D002876:Chromosomes, Bacterial / Q000235:genetics; D003603:Cytotoxins / Q000235:genetics; D023061:Gene Order / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D005818:Genetic Engineering / Q000379:methods*; D005819:Genetic Markers / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D032023:Integrons / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics; D012985:Software Design; D014737:Vibrionaceae / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; C068355:CcdA protein, Bacteria; C068356:CcdB protein, Plasmid F; D003603:Cytotoxins; D005819:Genetic Markers