Dataset Information

A purified mariner transposase is sufficient to mediate transposition in vitro.

ABSTRACT: Mariners are a widespread and diverse family of animal transposons. Extremely similar mariners of the irritans subfamily are present in the genomes of three divergent insect host species, which strongly suggests that species-specific host factors are unnecessary for mobility. We tested this hypothesis by examining the activity of a purified transposase from one of these elements (Himar1) present in the horn fly, Haematobia irritans. Himar1 transposase was sufficient to reproduce transposition faithfully in an in vitro inter-plasmid transposition reaction. Further analyses showed that Himar1 transposase binds to the inverted terminal repeat sequences of its cognate transposon and mediates 5' and 3' cleavage of the element termini. Independence of species-specific host factors helps to explain why mariners have such a broad distribution and why they are capable of horizontal transfer between species.

SUBMITTER: Lampe DJ

PROVIDER: S-EPMC452289 | biostudies-other | 1996 Oct

REPOSITORIES: biostudies-other

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A purified mariner transposase is sufficient to mediate transposition in vitro.

Lampe D J DJ Churchill M E ME Robertson H M HM

The EMBO journal 19961001 19

Mariners are a widespread and diverse family of animal transposons. Extremely similar mariners of the irritans subfamily are present in the genomes of three divergent insect host species, which strongly suggests that species-specific host factors are unnecessary for mobility. We tested this hypothesis by examining the activity of a purified transposase from one of these elements (Himar1) present in the horn fly, Haematobia irritans. Himar1 transposase was sufficient to reproduce transposition fa ...[more]

PMID: 8895590

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Project description:BackgroundMariner elements represent the most successful family of autonomous DNA transposons, being present in various plant and animal genomes, including humans. The introduction and co-evolution of mariners within host genomes imply a strict regulation of the transposon activity. Biochemical data accumulated during the past decade have led to a convergent picture of the transposition cycle of mariner elements, suggesting that mariner transposition does not rely on host-specific factors. This model does not account for differences of transposition efficiency in human cells between mariners. We thus wondered whether apparent similarities in transposition cycle could hide differences in the intrinsic parameters that control mariner transposition.Principal findingsWe find that Mos1 transposase concentrations in excess to the Mos1 ends prevent the paired-end complex assembly. However, we observe that Mos1 transposition is not impaired by transposase high concentration, dismissing the idea that transposase over production plays an obligatory role in the down-regulation of mariner transposition. Our main finding is that the paired-end complex is formed in a cooperative way, regardless of the transposase concentration. We also show that an element framed by two identical ITRs (Inverted Terminal Repeats) is more efficient in driving transposition than an element framed by two different ITRs (i.e. the natural Mos1 copy), the latter being more sensitive to transposase concentration variations. Finally, we show that the current Mos1 ITRs correspond to the ancestral ones.ConclusionsWe provide new insights on intrinsic properties supporting the self-regulation of the Mos1 element. These properties (transposase specific activity, aggregation, ITR sequences, transposase concentration/transposon copy number ratio...) could have played a role in the dynamics of host-genomes invasion by Mos1, accounting (at least in part) for the current low copy number of Mos1 within host genomes.

Dataset Information

A purified mariner transposase is sufficient to mediate transposition in vitro.

Publications

A purified mariner transposase is sufficient to mediate transposition in vitro.

Similar Datasets

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