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Real-Time Quantification of the Effects of IS200/IS605 Family-Associated TnpB on Transposon Activity
Published on: January 20, 2023
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Transposon-associated TnpB is a programmable RNA-guided DNA endonuclease
Tautvydas Karvelis1, Gytis Druteika2, Greta Bigelyte2
1Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania. tautvydas.karvelis@bti.vu.lt.
Nature
|October 7, 2021
Summary
The study reveals that the transposon protein TnpB acts as an RNA-guided DNA nuclease, crucial for transposition. This finding confirms TnpB as a progenitor of CRISPR-Cas systems and a potential tool for genome editing.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Transposition reshapes genomes via mobile genetic elements like insertion sequences.
- The transposase TnpA is essential for mobilization, while the accessory TnpB protein's function remains largely unknown.
- TnpB was bioinformatically linked to CRISPR-Cas nucleases, but its biochemical activity was uncharacterized.
Purpose of the Study:
- To elucidate the biochemical function of the TnpB protein.
- To investigate the role of TnpB in the transposition of IS200/IS605 insertion sequences.
- To explore the potential of TnpB as a progenitor for novel genome editing tools.
Main Methods:
- Biochemical assays to characterize TnpB activity.
- RNA-guided DNA cleavage experiments using Deinococcus radiodurans ISDra2 TnpB.
- Reprogramming TnpB for targeted DNA cleavage in human cells.
Main Results:
- TnpB functions as an RNA-directed nuclease, guided by transposon-derived RNA.
- TnpB cleaves DNA specifically adjacent to a 5'-TTGAT motif.
- TnpB was successfully reprogrammed to target and cleave DNA in human cells.
Conclusions:
- TnpB plays a significant role in transposition, acting as an RNA-guided nuclease.
- This study provides experimental evidence for TnpB as a functional ancestor of CRISPR-Cas nucleases.
- TnpB represents a novel prototype for developing advanced genome editing technologies.
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