Table 1 Comparison of genome editing technologies
From: CRISPR/Cas9 system: recent applications in immuno-oncology and cancer immunotherapy
| Â | ZFN | TALEN | CRISPR |
|---|---|---|---|
Length of target sequence | 9-12 bp | 14-20 bp | 20 bp + PAM |
Target DNA recognition | DNA-protein interaction | DNA-protein interaction | DNA-RNA interaction |
Target site | Single | Single | Multiple |
Nuclease | Fok1 | Fok1 | Cas9 |
Efficacy | Moderate | Moderate | High |
Specificity | Low | Moderate | High |
Toxicity | High | Moderate | Moderate |
Design difficulty | Complicated | Complicated | Simple |
Clinical trial | Moderate | Low | High |
Disadvantage | Toxic; limited site selection; expensive | Difficult to deliver due to the large size | Target DNA must have an upstream PAM; off-target effects |