Fig. 1. Split and intact prime editors function with similar efficiencies in human HEK293T cells.

Schematics at the top illustrate the location of MMLV-RT (pink box) with respect to nSpCas9-H840A (white box) for three intact variants (C-terminal, N-terminal, and inlaid fusion at G1247) and the separate expression of nSpCas9 and the MMLV-RT pentamutant for Split-PE (not drawn to scale). Dot and bar plots represent the frequencies of prime editing induced at 11 genomic loci targeted with prime editing gRNAs (pegRNAs) and nicking gRNAs (ngRNAs) using the PE3 approach. The types of desired edits induced are grouped as substitutions, insertions (ins.), or deletions (del.). For substitution edits, frequencies of pure prime edits (PPE), impure prime edits (IPE), and byproducts are shown separately. For insertion and deletion edits, IPE and byproduct frequencies are added together and shown as a single bar next to their respective PPE frequencies⁶. Bar graphs represent the mean, error bars show standard deviation (s.d.), and dots represent values of replicates (n=3; independent replicates). bp, base pairs. FLAG, Flag tag (DYKDDDDK)³³ with an SGS-linker).