Transposons: Prokaryotic

Abstract

Transposons are DNA (deoxyribonucleic acid) segments found ubiquitously in the genomes of living organisms and capable of moving from place to place within a genome. They are frequently associated with the sequestration and transmission of accessory genes in bacteria and archaea. They carry genes such as resistance to anti‐bacterials, virulence and symbiotic factors and catabolism of xenobiotics. They have a large impact on public health by facilitating the spread of these phenotypic characters. Transposons generate a variety of DNA rearrangements that have profound consequences for cell survival and evolution. These rearrangements are associated with transposition events (catalysed by transposon‐specific enzymes, transposases) but repeated transposon copies can act as portable regions of homology and undergo homologous recombination using the host recombination system. Transposons are diverse in structure, highly regulated by a multitude of mechanisms but only specify a limited number of catalytic chemistries. Transposons can represent a large proportion of prokaryotic genomes. Key Concepts Transposable elements are ubiquitous and show a high degree of diversity. Transposable elements use a limited number of different chemical mechanisms for their transposition. Transposons are key elements in the short‐term evolution of prokaryotic genomes. Trasposons are central to driving the spread of antibiotic resistance.

Mobile Genetic Elements Associated with Antimicrobial Resistance

“…Transposition occurs via a replicative mechanism in which TnpA catalyzes generation of a cointegrate structure, consisting of directly repeated copies of the transposon separating the original donor and recipient molecules (26). The cointegrate is then resolved into separate molecules, each containing a copy of the transposon, by site-specific recombination between the two directly oriented res sites, catalyzed by TnpR (68,69). Transposition creates TSD of 5 bp (or occasionally 6 bp).…”

“…Transposition creates TSD of 5 bp (or occasionally 6 bp). Tn3 family members demonstrate transposition immunity, i.e., transposition of a second element into the same vicinity or the same DNA molecule is inhibited (68,69), but homologous and/or res-mediated recombination between related elements can occur, creating hybrid elements.…”