Precise Gene Editing in Rice and Tomatoes Using a Tiny Enzyme

Greg Howard
30th May, 2024

Precise Gene Editing in Rice and Tomatoes Using a Tiny Enzyme

Left: Tomato (Solanum lycopersicum), right: Asian Rice (Oryza sativa)

Composite image created by Natural Science News / CC BY. Adapted from photos by Patrick Hacker and Kim, Hyun-tae.

Key Findings

  • Researchers at the University of Electronic Science and Technology of China studied the compact Un1Cas12f1 CRISPR nuclease for genome editing in rice and tomato protoplasts
  • They found that using Pol III promoters significantly enhanced genome editing efficiency compared to Pol II promoters
  • The study also identified the PAM requirements and mutation profiles of Un1Cas12f1, crucial for designing effective CRISPR systems
The clustered regularly interspaced short palindromic repeats (CRISPR) systems have revolutionized genetic engineering by offering powerful tools for genome manipulation in both prokaryotic and eukaryotic organisms. Despite the versatility of widely used nucleases like Cas9 and Cas12a/b, their large protein sizes pose significant challenges for cellular delivery and application in genetic engineering and crop development. A recent study conducted by researchers at the University of Electronic Science and Technology of China has explored the potential of a more compact CRISPR nuclease, Un1Cas12f1, for genome editing in rice and tomato protoplasts[1]. The study focused on the miniature Un1Cas12f1 type-V CRISPR nuclease derived from uncultured archaea. Compact nucleases like Cas12f1, which range from 400 to 600 amino acids, offer advantages in terms of delivery and application, particularly in plant and human cells[2]. Previous research has shown that smaller CRISPR systems like Cas12f1 can effectively cleave double-stranded DNA and induce targeted modifications[2][3]. However, their efficacy in eukaryotic cells, especially plants, required further investigation. In their experiments, the researchers evaluated the genome editing efficiency of Un1Cas12f1 in rice and tomato protoplasts by using reengineered guide RNA modifications, specifically the ge4.1 variant. They compared the performance of polymerase II (Pol II) and polymerase III (Pol III) promoters to drive guide RNA expression. The results revealed that Pol III promoters significantly enhanced genome editing efficiency compared to Pol II promoters. This finding is crucial as it highlights the importance of promoter selection in optimizing CRISPR-based genome editing systems for plants. Interestingly, the study also characterized the protospacer adjacent motif (PAM) requirements and mutation profiles of Un1Cas12f1 in both rice and tomato. PAM sequences are short DNA sequences immediately following the target DNA region, essential for CRISPR activity. Understanding these requirements is vital for designing effective CRISPR systems. The researchers found that the engineered Un1Cas12f1-RRA variant did not outperform the wild-type Un1Cas12f1 nuclease in plant cells, suggesting that further protein engineering and innovative approaches are necessary to enhance Un1Cas12f1's genome editing capabilities. This study builds on earlier findings that have shown the potential of compact CRISPR nucleases like Cas12f1 for genome editing[2][3][4]. For instance, previous research demonstrated that SpCas12f1, another miniature nuclease, could function in both plant and human cells, paving the way for developing more efficient genome editing tools[2]. Additionally, comparisons between different CRISPR systems have highlighted the unique properties and applications of various nucleases, including Cas12f1, Cas12a, and Cas9[4]. The current study contributes to this growing body of knowledge by providing insights into the performance of Un1Cas12f1 in plant cells and identifying areas for improvement. In summary, the research conducted by the University of Electronic Science and Technology of China demonstrates the potential of the miniature Un1Cas12f1 CRISPR nuclease for genome editing in rice and tomato protoplasts. The study highlights the importance of promoter selection and provides valuable information on PAM requirements and mutation profiles. While the engineered Un1Cas12f1-RRA variant did not show improved performance, the findings underscore the need for continued protein engineering and innovative approaches to optimize Un1Cas12f1 for plant genome editing. This research represents a significant step towards developing more efficient and versatile genome editing tools for agricultural and biotechnological applications.

BiotechGeneticsPlant Science

References

Main Study

1) Genome editing in rice and tomato with a small Un1Cas12f1 nuclease.

Published 28th May, 2024

https://doi.org/10.1002/tpg2.20465

Related Studies

2) Miniature type V-F CRISPR-Cas nucleases enable targeted DNA modification in cells.

https://doi.org/10.1038/s41467-021-26469-4

3) Programmed DNA destruction by miniature CRISPR-Cas14 enzymes.

https://doi.org/10.1126/science.aav4294

4) Comparison of DNA targeting CRISPR editors in human cells.

https://doi.org/10.1186/s13578-023-00958-z


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