Source- This post on Genome Editing and TnpB has been created based on the article “ICAR, Penn State team makes a tool small enough to edit plant genomes” published in “The Hindu” on 22 August 2024.
Why in News?
Researchers have developed a plant genome editor using a protein derived from Deinococcus radiodurans bacteria, known for surviving extreme conditions.
About Genome Editing
1. Genome editing is a technology that allows scientists to make precise changes to DNA which can lead to alterations in physical traits, such as eye color, and influence the risk of diseases.
2. How Genome Editing Works: These technologies work like scissors, cutting the DNA at a specific location. After the cut, scientists can remove, add, or replace segments of DNA to achieve the desired changes.
3. Evolution of Genome Editing Technologies: The first genome editing technologies emerged in the late 1900s, marking the beginning of our ability to manipulate DNA at specific sites.
4. Introduction of CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a gene editing technology, which replicates natural defence mechanism in bacteria to fight virus attacks, using a special protein called Cas9. This technology has made DNA editing simpler, faster, cheaper, and more accurate.
6. Challenges with CRISPR in Plants: CRISPR is often too big to work effectively in plant cells. The main proteins it uses that are Cas9 and Cas12 are too bulky which make it challenging to use in plant genome editing.
About TnpB
1. About: TnpB is a small transposons protein from the bacterium “Deinococcus radiodurans” that is used for precise genome editing.
Note: Transposons are a group of genes that can move within the genome.
2. Composition: It is made of around 400 amino acids. It is less than half the size of Cas9 and Cas12.
3. How TnpB Works: TnpB works by binding to specific DNA sequences and using RNA to guide the removal or modification of unwanted genetic material. This precise editing capability allows for targeted changes in plant genes, leading to improvements in desirable traits such as yield, disease resistance, or nutritional content.
4. The TnpB system has achieved an editing success rate of 33.58% in plant genomes, which is higher than traditional CRISPR methods for some targets. It has been effective in both monocot and dicot plants.
5. To enhance TnpB’s efficiency in plants, researchers have modified its genetic code to better align with plant biology and optimized the elements that control its expression. This makes TnpB a promising tool for advanced plant genome editing.
6. Potential Benefits: This new genome editing tool could help develop crops that are more resistant to pests, less prone to damage from weather like cyclones, and free of harmful anti-nutrient factors.
Difference between TnpB and CRISPR
| Point of differences | TnpB | CRISPR |
| Size and Delivery | Smaller and easier to deliver into cells, especially useful in plants. | Larger, making delivery more complex, but widely adaptable. |
| Targeting Mechanism | Uses a specific sequence (TAM) for precise DNA targeting, with high specificity. | Targets DNA using a PAM sequence with guide RNA, effective but sometimes limited by PAM availability. |
| Efficiency | Achieves a 33.58% success rate in plant genomes, potentially more effective for certain targets. | Generally efficient but can vary depending on the target site. |
| Versatility | Newer and mainly focused on plants, with potential for growth in other areas. | Highly versatile, used across many fields, from agriculture to medicine. |
Read More: Human genome editing
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