Influence of transposition mechanisms on genome impact

The way in which strand cleavages and transfers occur during transposition also affects the outcome of the transposition events and therefore impinges on genome structure. For IS with DDE Tpases, Tn3 and IS6 family members generate fusions or cointegrates between the donor and target replicons by a process of replicative transposition, presumably by TPRT (Target primed replicative transposition) (Hickman, et al., 2010, Hickman & Dyda, 2015, Siguier, et al., 2015) (Figs 1.23.1 and 1.23.2 top). However, in the event of intramolecular transposition, this type of mechanism is expected to give rise to inversions with a copy of the IS at each junction or inversions with a single IS copy remaining and a second copy segregating with a circularized deletion (Shapiro, 1979) (Fig 1.23.2 bottom; see (He, et al., 2015)). Note that similar effects are also known to occur by homologous recombination between two inverted or directly repeated IS copies in a replicon. Other known mechanisms such as cut-and-paste, or copy-and-paste (DPRT, Donor primed replicative transposition) (Curcio & Derbyshire, 2003) would not generate this type of genomic rearrangement but could contribute to genomic modifications in other ways such as "nearly precise excision" (Ross, et al., 1979, Ross, et al., 1979) or by using alternative sequences which resemble their IR (Ohtsubo, et al., 1980, Polard, et al., 1994).

References :

• Curcio MJ & Derbyshire KM (2003) The outs and ins of transposition: from Mu to Kangaroo. Nat Rev Mol Cell Biol 4: 865-877.
• He S, Hickman AB, Varani AM, Siguier P, Chandler M, Dekker JP & Dyda F (2015) Insertion Sequence IS26 Reorganizes Plasmids in Clinically Isolated Multidrug-Resistant Bacteria by Replicative Transposition. MBio 6: e00762.
• Hickman AB & Dyda F (2015) Mechanisms of DNA Transposition. Microbiol Spectr 3: MDNA3-0034-2014.
• Hickman AB, Chandler M & Dyda F (2010) Integrating prokaryotes and eukaryotes: DNA transposases in light of structure. Critical Reviews in Biochemistry and Molecular Biology 45: 50-69.
• Ohtsubo E, Zenilman M & Ohtsubo H (1980) Plasmids containing insertion elements are potential transposons. Proc Natl Acad Sci U S A 77: 750-754.
• Polard P, Seroude L, Fayet O, Prere MF & Chandler M (1994) One-ended insertion of IS911. J Bacteriol 176: 1192-1196.
• Ross DG, Swan J & Kleckner N (1979) Nearly precise excision: a new type of DNA alteration associated with the translocatable element Tn10. Cell 16: 733-738.
• Ross DG, Swan J & Kleckner N (1979) Physical structures of Tn10-promoted deletions and inversions: role of 1400 bp inverted repetitions. Cell 16: 721-731.
• Shapiro JA (1979) Molecular model for the transposition and replication of bacteriophage Mu and other transposable elements. Proc.Natl.Acad.Sci.U.S.A. 76: 1933-1937.
• Siguier P, Gourbeyre E, Varani A, Ton-Hoang B & Chandler M (2015) Everyman's Guide to Bacterial Insertion Sequences. Microbiol Spectr 3: MDNA3-0030-2014.