Prime editing enables precise DNA 'search and replace'

Andrew Anzalone in David Liu's lab fused a Cas9 nickase to an engineered reverse transcriptase, guided by a 'prime editing guide RNA' that both finds the target site and encodes the desired edit. The system can perform targeted insertions, deletions and all 12 possible base-to-base conversions without cutting both DNA strands or needing a separate donor template. Prime editing is estimated to be able to correct roughly 90% of known pathogenic human genetic variants, making it one of the most versatile editing tools developed to date.