Modified loop2 epegRNA improve prime editing efficiency.

Prime editor (PE) has wide application prospects in disease treatment due to its diversity of editing outcomes. However, the editing efficiency of PE still needs to be further improved for therapeutic applications. Here, we increase the probability of hybridization of the pegRNA primer binding site (PBS) to single-stranded DNA flap by adding additional PBS sequence and reverse transcription template (RTT) to the loop region of pegRNA. The selection of loop and the design of loop length are optimized. The resulting modified loop2 epegRNA (ML-epegRNA) showed higher prime editing efficiency than that of the epegRNA in HEK293T cells. In addition, we used ML-epegRNA for PE editing of multiple editing types in multiple cell lines, and the results showed a general improvement in editing efficiency. Overall, the ML-epegRNA expands the capabilities of genome editing tools.