Engineered prime editors with minimal genomic errors

Area of Science:

• Molecular Biology
• Genome Engineering
• Biotechnology

Background:

• Prime editors enable targeted DNA sequence writing into genomic DNA.
• Current prime editors face challenges with efficiency and indel errors due to competing DNA strand dynamics.

Purpose of the Study:

• To discover mechanisms for improving prime editor efficiency and reducing indel errors.
• To engineer a next-generation prime editor with enhanced precision.

Main Methods:

• Investigated the role of Cas9-nickase mutations in promoting nicked end degradation.
• Engineered prime editors by exploiting nicked end degradation to suppress competing 5' strands.
• Integrated error-suppressing strategies with efficiency-boosting architectures to develop vPE.

Main Results:

• Discovered that specific Cas9-nickase mutations promote nicked end degradation, destabilizing competing 5' strands.
• Developed highly efficient prime editors with markedly reduced indel errors.
• The next-generation prime editor (vPE) demonstrated comparable efficiency to previous editors but with up to 60-fold lower indel errors.
• Achieved edit:indel ratios as high as 543:1 with vPE.

Conclusions:

• Nicked end degradation is a viable strategy to enhance prime editor performance.
• The engineered vPE represents a significant advancement in precise genome editing technology.
• vPE offers improved accuracy for therapeutic genome editing applications.