Prime editing updates: technological evolution, methodological expansion, and delivery strategies for <i>in vivo</i> applications

Prime editing is a next-generation genome editing technology that enables precise base substitutions, insertions, and deletions at target genomic loci without inducing double-strand breaks or requiring exogenous donor DNA.This system operates through a fusion protein composed of Cas9 nickase and reverse transcriptase together with prime editing guide RNA; it has emerged as a precise genome editing platform that overcomes the limitations of conventional double-strand break-inducing CRISPR-Cas9 systems.Since first reported in 2019, diverse methodological improvements from PE1 to PE7 have been achieved, leading to rapid advances in editing efficiency, expansion of the editable target range, correction of large genomic regions, and development of in vivo delivery technologies.In this review, we comprehensively discuss the fundamental working mechanism of prime editing, its methodological evolution, recent expansion strategies, and delivery platforms for therapeutic applications, and provide perspectives for future development.