Recent advances in prime editing system

Prime editing (PE) system is a newly developed and greatly revolutionized genome editing technology. The system is based on prime editors, which are composed of two components: A fusion protein of nCas9 (H840A) and reverse transcriptase (RT), and a pegRNA which contains a PBS (Primer binding site) sequence and an RT template (RTT) sequence. The PE system can realize all 12 types of base substitutions and small fragment DNA additions and deletions without double-strand breaks, which is a new paradigm for precision editing. In less than 4 years since its development in 2019, the PE system, as a universal technology platform, has been widely used in various fields such as healthcare and agriculture, generating a large number of excellent application cases such as new germplasm resources and gene therapy drugs. PE, as the most flexible and promising new means of precision genome editing, still suffers from low efficiency, insufficient ability to manipulate large fragments, complex design of system components (such as pegRNAs), incomplete evaluation of safety, and still requires in-depth research. This paper described in detail the technical principles and constraints of PE systems, comprehensively summarized the optimization strategies of PE systems since their development, and the current status of PE applications on animal and plant systems and medical fields. It also gave an outlook on the development prospects of PE.