Natural Transposon: Dmau\mariner
Natural Transposon: Dmau\mariner
Homolog-dependent gap repair is a frequent accompaniment to Dmau\mariner excision, estimated at 30% of all excision events. Dmau\mariner insertions are hotspots for recombination in Drosophila females, but only in the presence of functional transposase.
A modified Dmau\mariner element marked with a wild-type allele of cn is capable of mediating germ-line transformation of A.aegypti.
Dmau\mariner can stably integrate into the zebrafish genome, by transposition induced by Dmau\mariner\T transposase.
Comparison of integrase/transposase domains to new elements containing the DDE signature.
Dmau\mariner is capable of accurate transposition in the embryonic soma of D.melanogaster, L.cuprina and B.tryoni. Cloning of reporter genes into the element demonstrates the potential utility of the transposition assays for defining regions of the element that are important for accurate transposition.
Dmau\mariner is successfully introduced into the human parasite Leishmania major. Transposition is efficient and proceeded by the same mechanism as in Drosophila. Insertional activation of a gene is obtained establishing Dmau\mariner as a powerful genetic tool for Leishmania and other organisms.
The Dmau\mariner\TMos1 element of D.mauritiana is capable of generating chromosomal insertions into the genome of D.virilis. Copy number increases by spontaneous mobilization. Integration results in a characteristic 2bp TA duplication. One insertion resulted in a tandem array of 370bp repeats. Some insertions are apparently into heterochromatin.
Dmau\mariner is capable of excision in the embryonic soma of the Australian sheep blowfly, L.cuprina and to a lesser extent in the Queensland fruitfly, B.tryoni. Analysis of the empty excision sites provides an insight into the mechanism of mariner movement.
Dmau\mariner is able to transform efficiently within a species only distantly related to D.melanogaster.
The distribution and abundance of mariner-like elements in the melanogaster species subgroups suggests that the predominant mode of evolution of mariner-like elements is stochastic loss and vertical inactivation, balanced against occasional reinvasion of lineages by horizontal transmission.
Somatic genetic damage induced by movement of the Dmau\mariner element significantly decreases the life span of D.simulans but has no effect on the lifespan of D.melanogaster.
Distribution of the mariner element among Drosophilidae species is investigated using three different techniques (squash blots, Southern blots and PCR amplification). Results demonstrate the distribution of mariner is not uniform and does not follow the phylogeny of the host species. Analysis of geographical distributions of the element shows it is mainly present in Asia and Africa.
A vector for germline transformation of D.melanogaster has been constructed using the D.mauritiana mariner element.
Population biology and molecular evolution of the mariner element in the eight species of the melanogaster subgroup of the Drosophila subgenus Sophophora has been studied. The element occurs in D.simulans, D.mauritiana, D.sechellia, D.teissieri and D.yakuba, but not D.melanogaster, D.erecta or D.orena. Sequence comparisons suggest that the element was present in the ancestor of the species subgroup and was lost in some of the lineages. Most species that contain active elements also contain inactive elements.
Suspected relationship between Dmau\mariner and C.elegans Tc1 open reading frame is confirmed using BLOSUM matrices.
D.mauritiana has 20-30 copies of Dmau\mariner per genome, great variation in the genomic positions of the elements, and few deleted copies.
The distribution of the mariner transposable element in the genus Drosophila has been examined. Sequences hybridising to Dmau\mariner are present in D.mauritiana, D.simulans, D.sechellia, D.yakuba and D.teissieri, but not D.melanogaster, D.erecta and D.orena.
The Ztub\mariner sequence has 97% identity to Dmau\mariner and the mariner sequence from Dmau\mariner has 92% identity to Dtsa\mariner. D.tsacasi is more related to D.mauritiana than Z.tuberculatus so the presence of the mariner sequence in Zaprionus may result from horizontal transfer.
Dmau\mariner has been cloned and sequenced.
Dmau\mariner element excision is imprecise both in the germline and soma.
First identified by a somatically and germ-line unstable mutation at white in D.mauritiana. Used as a transformation vector for D.melanogaster.
Etymology: "mariner" was not, as usually conjectured, named after Samuel Taylor Coleridge's 1798 poem "The Rime of the Ancient Mariner", although the eponymy is apt, but in honour of J.W. Jacobson's newborn daughter, Marin.