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Identification and characterization of the linear IS3 molecules generated by staggered breaks
Y Sekine1, N Eisaki, E Ohtsubo
1Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
The Journal of Biological Chemistry
|January 5, 1996
Summary
The IS3 transposase creates linear DNA molecules with 3-nucleotide overhangs, suggesting a novel transposition mechanism. These linear molecules are likely intermediates in the non-replicative transposition of insertion sequence IS3.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Insertion sequences (IS) are mobile genetic elements that transpose within genomes.
- IS3 insertion sequences encode a transposase via translational frameshifting.
- Previous studies showed IS3 transposase generates miniplasmids and IS3 circles.
Purpose of the Study:
- To investigate the molecular mechanisms of IS3 transposition.
- To identify novel intermediates in the IS3 transposition pathway.
Main Methods:
- Analysis of DNA molecules generated by IS3 transposase in vivo.
- Sequencing of flanking DNA regions.
Main Results:
- IS3 transposase generates linear IS3 molecules with 3-nucleotide 5'-overhangs.
- The overhang sequences match the flanking sequences of IS3 in the parental plasmid.
- Evidence suggests staggered double-strand breaks at IS3 ends initiate transposition.
Conclusions:
- Linear IS3 molecules with 5'-overhangs are novel intermediates in IS3 transposition.
- IS3 transposition likely proceeds via a non-replicative mechanism involving staggered DNA breaks.