Extended Data Fig. 5. Efforts to minimize the size of the prime editor protein.

Activity of full-length and intein-split SaPE2 by plasmid transfection in HEK293T cells with a pegRNA encoding the HEK3 +6 G-to-T edit. An intein split at previously validated position 740¹ was assessed to maintain on-target editing efficiency compared to full-length (SaPE2). The three N-terminal residues of the C-terminal extein are indicated, with ‘SMP’ being the native residues to SaCas9, and CFN as the consensus residues of Npu intein. b. PE ∆RNaseH maintains prime editing activity in cultured cells across a variety of edits. HEK293T cells were transfected with plasmids encoding PE2 or PE2 ∆RNaseH and pegRNA (PE2) or pegRNA and nicking sgRNA (PE3). Genomic DNA was harvested after three days and analyzed by HTS. Dots represent individual data points and error bars represent mean±SEM for n = 3 independent biological replicates.