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Updated: May 13, 2026
04:04
Real-Time Quantification of the Effects of IS200/IS605 Family-Associated TnpB on Transposon Activity
Published on: January 20, 2023
ISDra2 transposition in Deinococcus radiodurans is downregulated by TnpB
Cécile Pasternak1, Rémi Dulermo, Bao Ton-Hoang
1University Paris-Sud, Institut de Génétique et Microbiologie (Bât. 409), UMR 8621, Orsay F-91405, France.
Molecular Microbiology
|March 7, 2013
Summary
The transposase B (TnpB) protein from the ISDra2 element inhibits its own transposition. This regulatory role of TnpB is independent of host factors and requires its zinc finger motif.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Transposable elements (TEs) are mobile DNA sequences with diverse transposition mechanisms.
- The IS200/IS605 family of insertion sequences (IS) utilizes single-stranded DNA (ssDNA) for transposition, distinguishing them from classical IS.
- The ISDra2 element from Deinococcus radiodurans contains genes for transposase A (TnpA) and a second protein, TnpB, whose function is unknown.
Purpose of the Study:
- To investigate the function of the TnpB protein encoded by the ISDra2 transposable element.
- To determine the role of TnpB in the transposition process of ISDra2.
- To elucidate the mechanism and host-factor independence of TnpB's function.
Main Methods:
- Assessing the effect of TnpB expression on ISDra2 excision and insertion.
- Inducing ISDra2 transposition via gamma irradiation in host cells.
- Mutational analysis of the TnpB protein, focusing on its putative zinc finger motif.
- Evaluating TnpB's function in both homologous (Deinococcus radiodurans) and heterologous (Escherichia coli) hosts.
Main Results:
- TnpB significantly inhibits both the excision and insertion steps of ISDra2 transposition.
- The inhibitory effect of TnpB is observed even when transposition is induced by gamma irradiation.
- The integrity of TnpB's putative zinc finger motif is essential for its inhibitory activity.
- TnpB-mediated inhibition of ISDra2 transposition occurs in a heterologous Escherichia coli host, suggesting no reliance on Deinococcus-specific factors.
Conclusions:
- TnpB acts as a negative regulator of ISDra2 transposition.
- The zinc finger motif in TnpB is crucial for its regulatory function.
- TnpB-mediated regulation of transposition is independent of specific host cell components.
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