Transposons mariner

A second Drosophila transposon called mariner630 typifies the mariner / Tel transposon superfamily, which also contains members from nematodes,631 other invertebrates, fishes,632 amphibia,633 and possibly human beings.634 These transposons encode a transposase containing a D, D, D or D, D, E motif630 but no other proteins. They contain short 30-bp terminal inverted repeats and become inserted into host TA sequences.631 Movement of some repetitive sequences of the LINE635 and SINE636 families within the human genome may be assisted by mariner transposons.637... 

Garcia-Fernandez, J., Bayascas-Ramirez, J.R., Marfany, G., Munoz-Marmol, A.M., Casali, A., Baguna, J. and Salo, E. (1995) High copy number of highly similar Mariner-like transposons in planarian (platy-helminthe) evidence for a trans-phyla horizontal transfer. Molecular Biology and Evolution 12, 421-431. 

Many DDE transposases carry a DNA sequence-specific binding domain in their N-terminal regions and at least one domain involved in multimerization. Generally, the catalytic domain is located in the C-terminal part of the protein. The DDE domain is by far the most studied and best understood catalytic motif involved in transposition. It is found in many different types of transposon from retroviruses to Tc-Mariner, bacterial ISs, and transposons (4). 

For the widely dispersed Tc-Mariner transposon group, the transposase first cleaves within the 5 end of the transposon—the nontransferred strand. This activity resembles the nuclease activity (see above) that simply terminates at the cleavage step and does not take in charge the strand transfer step. Moreover, unlike transposition reactions, this cleavage does not require formation of a synaptic complex (29). The transferred strand is cleaved at the very tip of the TE. The fact that the nontransferred strand is cleaved within the transposon results in retention of the few TE-speciflc bases in the donor molecule after TE excision. After resealing and repair, the donor backbone retains several additional base pairs derived from the TE (called a scar) that marks the passage of the transposon (2). 

Interestingly, transposon Tn7 behaves in a similar way but, in this case, the 5 endonuclease activity is supplied by a separate enzyme whose structure resembles that of a type II restriction enzyme (30), and cleavage occurs cleanly at the transposon tip rather than within the TE. Transposition of Tn7, like most bacterial elements, does not leave a scar. In both the Tc-Mariner transposon group and the Tn7 family of transposons, the transposase then cleaves and transfers the 3 end in a true DDE transposition reaction (Fig. le). 

Lipkow K, Buisine N, Lampe DJ, Chalmers R. Early intermediates of mariner transposition catalysis without synapsis of the transposon ends suggests a novel architecture of the synaptic complex. Mol. Cell Biol. 2004 24 8301-8311. 

Dawson A, Finnegan DJ. Excision of the Drosophila mariner transposon mosl. Comparison with bacterial transposition and v(d)j recombination. Mol. Cell 2639 11 225-235. 

Reiter LT, Murakami T, Koeuth T, Pentao L, Muzny DM, Gibbs RA, et al. A recombination hotspot responsible for 2 inherited peripheral neuropathies is located near a mariner transposon-Uke element. Nature Genet 1996 12 288-97. 

A.L., and Melville, S.B. (2013) Use of a mariner-based transposon mutagenesis system to isolate Clostridium perfringens mutants deficient in gliding motility. / Bacterial., 195, 629-636. 

Cartman, S.T. and Minton, N.P. (2010) A mariner-based transposon system for in vivo random mutagenesis of Clostridium difficile. Appl. Environ. Microbiol., 76, 1103-1109. 

Bilyk, B., Weber, S., Myronovskyi, M., Bilyk, O. et al. (2013) In vivo random mutagenesis of streptomycetes using mariner-based transposon Himarl. Appl. Microbiol. Biotechnol, 97 (1), 351-359. 

Members of the mariner family of transposons are particularly useful as genetic tools in heterologous hosts because they do not require host cofactors to be functional and because they integrate randomly into the genome, recognizing a T-A dinucleotide sequence to insert. Recently, hyperactive mutants of the mariner element Himarl were isolated that possessed an increased frequency of transposition over the wild-type allele (10,11). These features have allowed... 

Bourhy, P., Louvel, H., Saint Girons, I., and Picardeau, M. (2005) Random inser-tional mutagenesis of Leptospira interrogans, the agent of leptospirosis, using a mariner transposon. J. Bacteriol. 187, 3255-3258. 

Homologs of the Tel element in C. elegans and those of the mariner transposon in D. mauritiana, are probably the most widespread DNA transposons in nature (70). The presence of Tcl/mariner-Vikc elements in many different species indicates that, in contrast to P-elements, they are independent of any host factors and... 

Tcl/marmer-like elements have been found in many vertebrate genomes (75-79). However, unlike tol2 in medaka, all the transposon copies isolated to date are inactive remnants of once active transposons. Inspired by the potential for a vertebrate transposon Ivies and colleagues engineered a functional Tcl/mariner-like transposon from inachve copies of several fish species and named it Sleeping Beauty (SB (80)). The SB transposase has been shown to efficiently mediate transposition in cells from fish, mouse, and human in culture (80) and has been used as a genetic tool in the mouse in vivo (81-84). Within the last several years SB has been developed into an efficient gene transfer tool also in medaka and zebrafish (41,43,44). 

Plasterk RH (1996) The Tcl/mariner transposon family. Curr Topics Microbiol Immunol 204 125-143. 

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