proPE can greatly improve allele/gene specificity — even where classical PE is not effective.

ProPE shows lower off-target editing than classic PE.

The biggest jumps appear where classic PE underperforms: proPE raises low-efficiency edits to practical levels on challenging sites.

proPE excels most at target-distal edits—productive even when the edit lies far from the nick, expanding the practical editing window.

Tuning matters: with proPE, less nicking can mean more editing.

proPE more effectively completes partially extended DNA strands…

Truncation of the PBS-RTT causes less inhibition to proPE than to PE: #CRISPR

The inhibition due to intramolecular PBS spacer interactions is not apparent with proPE

Where classic PE stalls (A–E), proPE adds corrective steps (A*–E*)—from nicking and RT priming to flap resolution — boosting efficiency across the entire editing path.

Fig. 1:

proPE splits tasks between two guides: engRNA nicks the DNA (exposing the non-target strand); tpgRNA carries PBS+RTT and binds nearby with a truncated spacer, delivering the template without cutting.
See schematics. #CRISPR #primeediting