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Transposase-induced excision and circularization of the bacterial insertion sequence IS911
1Laboratory of Molecular Genetics and Microbiology (CNRS), Toulouse, France.
The EMBO Journal
|December 1, 1992
Summary
The IS911 transposon uses OrfAB protein for DNA excision and transposition. OrfA protein enhances this process while reducing circular DNA formation, with OrfB playing no detected role.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Transposable elements, like IS911, are mobile DNA sequences.
- Understanding the proteins involved in transposition is crucial for gene regulation and genome stability.
Purpose of the Study:
- To investigate the roles of three IS911-specified proteins (OrfA, OrfB, OrfAB) in transposition.
- To elucidate the mechanism of IS911 transposition, including intra- and intermolecular events.
Main Methods:
- In vivo transposition assays.
- Analysis of IS911 derivatives with mutations in terminal sequences.
- Protein expression studies (OrfA, OrfB, OrfAB).
Main Results:
- OrfAB alone mediates IS911 excision, circularization, and intermolecular transposition.
- OrfA enhances OrfAB-mediated transposition and reduces transposon circle formation.
- No role for OrfB was detected.
- Circle formation appears to be a site-specific intramolecular transposition event.
Conclusions:
- IS911 transposition involves a 'cut and paste' mechanism.
- OrfAB and OrfA proteins are key players in IS911 transposition.
- A single mechanism explains both intramolecular and intermolecular transposition events.