TnpB-based Genome editing system

ICAR-National Rice Research Institute recently sought to exploit a transposase enzyme, ISDra2TnpB, as a TnpB-based Genome editing system, in a bacterium that can survive in extreme environments.

About TnpB-based Genome editing:

• TnpB is a compact genome editing tool derived from the bacterium Deinococcus radiodurans.
• It belongs to the family of transposons or “jumping genes” that can move within the genome, targeting specific DNA sequences with the help of RNA.
• It is known for surviving extreme environmental conditions (extremophiles).
• TnpB proteins, consisting of about 400–500 amino acids, are significantly smaller than the commonly used CRISPR-associated proteins Cas9 (1000–1500 aa) and Cas12 (1100–1300 aa).
• This compactness facilitates easier delivery into plant cells, especially via methods like Agrobacterium-mediated T-DNA transformation or viral vector-based delivery.
• The TnpB-based system demonstrated an editing efficiency of 33.58% in average plant genomes, targeting regions that are inaccessible to Cas9 or Cas12.
• It was effective in both monocot (e.g., rice) and dicot (e.g., Arabidopsis) plant species.
• TnpB requires the presence of a transposon-associated motif (TAM) for DNA cleavage, providing a high degree of specificity in genome editing.

Applications:

• It has the potential to improve crops by enhancing traits such as nutritional content, yield, and resistance to drought and pests.
• It can also be used to modify microbes for targeted pest control and to enhance natural plant defense mechanisms.
• The research team plans to explore and refine TnpB variants from different organisms to expand their applicability in various plant species.
• This could help overcome the limitations of Cas9 and Cas12 in plant genome engineering.

Ref: Source

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