TAPE-seq is a cell-based method for predicting genome-wide off-target effects of prime editor

Prime editors (PEs) are powerful tools that widen the possibilities for sequence modifications during genome editing. Although methods based on the analysis of Cas9 nuclease or nickase activity have been used to predict genome-wide off-target activities of PEs, no tool that directly uses PEs for this purpose has been reported yet. In this study, we present a cell-based assay, named TAgmentation of Prime Editor sequencing (TAPE-seq), that provides genome-wide off-target candidates for PEs. TAPE-seq analyses are successfully performed using many different versions of PEs. The TAPE-seq predictions are compared with results from two other off-site prediction methods, Cas9 nuclease-based GUIDE-seq and Cas9 nickase-based Digenome-seq (nDigenome-seq). TAPE-seq shows a lower miss rate, and a higher area under the receiver operating characteristic curve compared to the other methods. TAPE-seq also identified valid off-target sites that were missed by the other methods.