BacPE: a versatile prime-editing platform in bacteria by inhibiting DNA exonucleases

Prime editing allows precise installation of any single base substitution and small insertions and deletions without requiring homologous recombination or double-strand DNA breaks in eukaryotic cells. However, the applications in bacteria are hindered and the underlying mechanisms that impede efficient prime editing remain enigmatic. Here, we report the determination of vital cellular factors that affect prime editing in bacteria. Genetic screening of 129 Escherichia coli transposon mutants identified sbcB , a 3ʹ→5ʹ DNA exonuclease, as a key genetic determinant in impeding prime editing in E. coli , combinational deletions of which with two additional 3ʹ→5ʹ DNA exonucleases, xseA and exoX , drastically enhanced the prime editing efficiency by up to 100-fold. Efficient prime editing in wild-type E. coli can be achieved by simultaneously inhibiting the DNA exonucleases via CRISPRi. Our results pave the way for versatile applications of prime editing for bacterial genome engineering. Prime editing in bacteria is currently inefficient. Here the authors report BacPE, a versatile prime editing platform in Escherichia coli that works by inhibiting 3′→5′ DNA exonucleases, highlighting the intrinsic genetic factors that are adverse to efficient prime editing.