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A Tn21 terminal sequence within Tn501: complementation of tnpA gene function and transposon evolution
Molecular & General Genetics : MGG
|January 1, 1984
Summary
The mercury-resistance transposon Tn501 shares a sequence with Tn21, suggesting Tn501 evolved from a Tn21-like element. This finding clarifies the evolutionary origins of bacterial transposons.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Transposons are mobile genetic elements crucial for bacterial evolution.
- Tn501, Tn21, and Tn1721 are mercury-resistance transposons with distinct structures and functions.
- Understanding transposon evolution provides insights into bacterial adaptation and horizontal gene transfer.
Purpose of the Study:
- To investigate the evolutionary relationship between the mercury-resistance transposons Tn501, Tn21, and Tn1721.
- To elucidate the role of inverted terminal repeats (IRs) in transposon transposition and evolution.
- To determine the origin of Tn501 based on sequence homology and functional complementation.
Main Methods:
- Comparative sequence analysis of transposon IRs.
- Functional complementation assays to assess transposition activity.
- Genetic manipulation of transposon mutants to study transposition mechanisms.
Main Results:
- Tn501 contains a sequence identical to an inverted terminal repeat (IR) of Tn21.
- Transposition of a Tn501 deletion mutant (Tn820) showed dependence on both Tn21 and Tn501 IR sequences.
- Complementation experiments revealed functional differences in transposition mediated by Tn501, Tn21, and Tn1721.
Conclusions:
- The findings suggest Tn501 evolved from a Tn21-like element that transposed into another transposable element.
- The study highlights the importance of IR sequences in mediating transposition and shaping transposon evolution.
- This research contributes to understanding the complex evolutionary pathways of mobile genetic elements in prokaryotes.