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Published on: March 29, 2019
Sub-terminal sequences modulating IS30 transposition in vivo and in vitro
Mónika Szabó1, János Kiss, Zita Nagy
1Agricultural Biotechnology Center, 4 Szent-Györgyi Albert str., H-2100, Gödöllo, Hungary.
Journal of Molecular Biology
|November 21, 2007
Summary
Sub-terminal sequences adjacent to insertion sequence (IS) inverted repeats are crucial for transposition. A novel figure-of-eight intermediate, formed by transposase, is essential for this process, highlighting a conserved transposition mechanism.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Insertion sequences (ISs) are mobile genetic elements that transpose within genomes.
- Inverted repeats (IRs) at the ends of IS elements are essential for transposition.
- The precise mechanisms governing IS transposition, particularly the role of flanking sequences, are not fully understood.
Purpose of the Study:
- To investigate the role of sub-terminal sequences adjacent to IS30 inverted repeats in transposition.
- To characterize the transposition intermediate formed by IS30 transposase.
- To determine if the figure-of-eight transposition intermediate is conserved across different IS families.
Main Methods:
- Development of a cell-free recombination system for studying IS30 transposition.
- In vivo and in vitro assays to assess the impact of sub-terminal sequences on transposition activity.
- Biochemical analysis to identify and characterize transposition intermediates.
Main Results:
- Sub-terminal sequences adjacent to IS30 inverted repeats are required for optimal transposition.
- Transposase catalyzes the formation of a figure-of-eight transposition intermediate, with IRs held by a single-strand bridge.
- This figure-of-eight structure, previously observed in IS3 family elements, is demonstrated here in a non-IS3 family element, suggesting broader conservation.
- Absence of sub-terminal sequences impairs figure-of-eight formation and transposition activity.
- Specific enhancer elements within the sub-terminal regions were identified, with distinct sequence requirements and functional properties.
Conclusions:
- Sub-terminal sequences play a critical role in regulating IS30 transposition by facilitating the formation of the figure-of-eight intermediate.
- The figure-of-eight mechanism appears to be a conserved feature across diverse IS families.
- These findings reveal a subtle regulatory mechanism for IS transposition involving transposase-dependent enhancer elements.
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