


| Situation | Guide RNA Suggestions | 
|---|---|
| Limited budget, no other constraints | Two-part guide RNA | 
| High endo- or exo-nuclease activity in cells | Single guide RNA (first choice) | 
| OR (next choice if the first choice does not work), two-part guide RNA with many chemical modifications,* | |
| OR (third choice, if the above choices do not work), single guide RNA with many chemical modifications** | |
| Delivery of pre-formed Cas9 protein | Two-part guide RNA, OR single guide RNA (both choices are equally likely to work) | 
| Delivery of mRNA or plasmid coding for Cas9 | Single guide RNA for longer stability | 
| Low editing efficiency with single guide RNA | Two-part guide RNA (first choice), | 
| OR try another target site (second choice if the first choice does not work) | |
| Low editing efficiency with two-part guide RNA | Single guide RNA (first choice), | 
| OR try another target site (second choice if the first choice does not work) | 
RUO24-3156_001