title: The integron/gene cassette system: an active player in bacterial adaptation.
abstract: The integron includes a site-specific recombination system capable of integrating and expressing genes contained in structures called mobile gene cassettes. Integrons were originally identified on mobile elements from pathogenic bacteria and were found to be a major reservoir of antibiotic-resistance genes. Integrons are now known to be ancient structures that are phylogenetically diverse and, to date, have been found in approximately 9% of sequenced bacterial genomes. Overall, gene diversity in cassettes is extraordinarily high, suggesting that the integron/gene cassette system has a broad role in adaptation rather than being confined to simply conferring resistance to antibiotics. In this chapter, we provide a review of the integron/gene cassette system highlighting characteristics associated with this system, diversity of elements contained within it, and their importance in driving bacterial evolution and consequently adaptation. Ideas on the evolution of gene cassettes and gene cassette arrays are discussed.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Labbate
authors.forename: Rebecca Josephine
authors.initials: RJ
authors.lastname: Case
authors.forename: Hatch W
authors.initials: HW
authors.lastname: Stokes
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D001419:Bacteria / Q000235:genetics*; D018407:Bacterial Physiological Phenomena; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D032023:Integrons; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004269:DNA, Bacterial