RT Journal Article SR Electronic T1 Awakening prime editing for precision engineering of probiotic Escherichia coli Nissle 1917 JF bioRxiv FD Cold Spring Harbor Laboratory SP 2024.10.28.620590 DO 10.1101/2024.10.28.620590 A1 Chen, Pei-Ru A1 Wei, Ying A1 Li, Xin A1 Yu, Hai-Yan A1 Wang, Shu-Guang A1 Yuan, Xian-Zheng A1 Xia, Peng-Fei YR 2024 UL http://biorxiv.org/content/early/2024/10/28/2024.10.28.620590.abstract AB CRISPR-Cas systems are transforming precision medicine with engineered probiotics as next-generation diagnostics and therapeutics. To promote human health and treat disease, engineering probiotic bacteria demands maximal versatility to enable non-natural functionalities while minimizing undesired genomic interferences. Here, we present a streamlined prime editing approach tailored for probiotic Escherichia coli Nissle 1917 utilizing only essential genetic modules and an optimized workflow. This was realized by assembling a prime editor consisting of the CRISPR-Cas system from Streptococcus pyogenes with its native codons and a codon-optimized reverse transcriptase, and by orchestrating the induction levels. As a result, we achieved all types of prime editing in every individual round of experiments with efficiencies of 25.0%, 52.0% and 66.7% for DNA deletion, insertion, and substitution, respectively. A comprehensive evaluation of off-target effects revealed a significant reduction in unintended mutations, particularly in comparison to two different base editing methods. Leveraging the prime editing system, we developed a barcoding system for strain tracking and an antibiotic-resistance-gene-free platform to enable non-natural functionalities. Our prime editing strategy awakens back-to-basics CRISPR-Cas systems devoid of complex or extraneous designs, paving the way for future innovations in engineered probiotics.Competing Interest StatementThe authors have declared no competing interest.