Scientists Optimize Prime Editing For Rice And Wheat
Arthur T Knackerbracket has found the following story:
Many genetic and breeding studies have shown that point mutations and indels (insertions and deletions) can alter elite traits in crop plants. Although nuclease-initiated homology-directed repair (HDR) can generate such changes, it is limited by its low efficiency. Base editors are robust tools for creating base transitions, but not transversions, insertions or deletions. Thus, there is a pressing need for new genome engineering approaches in plants.
David R. Liu and his colleagues at Harvard University developed a new genome editing approach, prime editing, which uses engineered Cas9 nickase (H840A)-reverse transcriptase (RT) fusion proteins paired with a prime editing guide RNA (pegRNA) that encodes the desired edit in human cells.
Recently, a research team led by Prof. Gao Caixia of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences reported the optimization of a prime editing system (PPE system) for creating desired point mutations, insertions and deletions in two major cereal crops, namely, rice and wheat. The main components of a PPE system are a Cas9 nickase-RT fusion protein and a pegRNA.
Using the PPE system, these researchers produced all 12 kinds of single base substitutions, as well as multiple point mutations and small DNA insertions and deletions at 9 rice and seven wheat sites in protoplasts, with efficiencies up to 19.2%. The efficiency of PPE was strongly affected by the length of the primer binding site (PBS) and RT template.
More information: Prime genome editing in rice and wheat, Nature Biotechnology (2020). DOI: 10.1038/s41587-020-0455-x , https://nature.com/articles/s41587-020-0455-x
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