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Promiscuous target interactions in the mariner transposon Himar1
Karen Lipkow1, Nicolas Buisine, Ronald Chalmers
1Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
The Journal of Biological Chemistry
|August 31, 2004
Summary
Mariner transposition forms a stable strand transfer complex, with promiscuous target interactions occurring before or after DNA cleavage. This behavior may facilitate genome invasion after horizontal gene transfer.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Mariner elements are widespread DNA transposons.
- Early intermediates of mariner transposition have been previously studied.
- Understanding later reaction stages, particularly target interactions, is crucial.
Purpose of the Study:
- To characterize the late-stage target interactions of mariner transposition.
- To investigate the stability of the strand transfer complex.
- To explore the cofactor requirements and target interaction timing.
Main Methods:
- Biochemical assays to analyze DNA-protein interactions.
- Analysis of transposon-target DNA complexes.
- Cofactor dependency studies for cleavage and strand transfer.
Main Results:
- The mariner strand transfer complex is highly stable.
- Transposase binding constrains DNA rotation at target site gaps.
- Strand transfer is supported by Ca2+, in addition to Mg2+ or Mn2+ required for cleavage.
- Mariner target interactions are promiscuous, occurring before or after flanking DNA cleavage.
Conclusions:
- Mariner transposition exhibits unique target interaction dynamics compared to bacterial counterparts.
- Promiscuous target interactions may promote local transposition and genome invasion.
- These findings offer insights into the evolution and horizontal transfer of transposons.