The prime editing machinery comprises a prime editing guide RNA (pegRNA) and a Cas9 nickase enzyme fused to a reverse transcriptase. | |||
The pegRNA binds to a matching sequence on the target DNA strand. | The Cas9 nickase cuts the unbound complementary strand, creating a flap. | ||
The dangling DNA flap binds to a matching sequence on the other end of the pegRNA. | The reverse transcriptase extends the flap by filling in the desired insertion sequence from the template next to the binding site. | ||
The edited flap competes with and displaces the flanking nucleotide sequence (right), which is ultimately removed by the cell. | The opposite strand is nicked and repaired to match the newly edited flap, completing the edit. |
- Anzalone AV, et al. Search-and-replace genome editing without double-strand breaks or donor DNA. Nature. 2019;576(7785):149-157.
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