Table 1.
Summarization for the refinement in PE.
| Designation of PE Systems |
Components of PE | Efficiency | ||
|---|---|---|---|---|
| Cas9 Nickcase | Reverse Transcriptase | pegRNA | ||
| PE1 | Cas9(H840A) nickase | M-MLV RT | the original pegRNA | 0.2–17% |
| PE2 | M-MLV RT (D200N/L603W/ T330P/T306K/W31S) |
1.6–5.1-fold | ||
| PE3 | + a sgRNA for nicking the non-edited strand | 3-fold compared to PE2 | ||
| ePE | fusing Csy-T2A |
+ a sgRNA & fusing a Csy4 recognition site into the 3′ end |
1.9-fold * | |
| unnamed | Cas9(H840A) nickase | epegRNA: incorporating evopreQ1 | 3–4-fold * | |
| aPE | apegRNA: inserting a C/G pair or changing each non-C/G pair to a C/G pair | 2.77-fold in indel-editing * | ||
| sPE | spegRNA: introducing same-sense mutations | 353-fold in base-editing * | ||
| x rPE | xr-pegRNA: appending a viral exoribonuclease-resistant RNA motif | 3.1-fold in base conversion * | ||
| G-PE | incorporating a hTR G-quadruplex |
similar to using epegRNA | ||
| PE4/PE5 | same as PE2 but transient expressing MLH1d | epegRNA | 7.7-fold compared to PE2/ 2.0-fold * |
|
| PE4max/PE5max | based on PE4/PE5, using a human codon-optimized RT/adding a linker | higher than PE2/PE3 | ||
| unnamed | based on PPE (similar to PE2) | PBS with a melting temperature of 30℃ and using dual pegRNAs |
at least 2.9-fold compared to PPE |
|
| ePPE | based on PPE but removing RT’s RNase H domain and incorporating a viral nucleocapsid protein | the original pegRNA | 5.8-fold compared to PPE | |
+: adding to PE1; *: compared to PE3.