Choosing a guide RNA for Cas12a
The Cas12a system uses a single crRNA to target the RNP to the site in the genome - no tracrRNA is needed. The crRNA is a single, 40–44 base, guide RNA, comprising a 20 base constant region (loop domain) and a 20–24 base target-specific region (protospacer domain). We typically recommend a 21 base protospacer domain for optimal activity. All Cas12a crRNAs are synthesized with proprietary chemical modifications, which protect the crRNA from degradation by cellular RNases and further improve on-target editing performance.
IDT crRNA format & vial sizes
| Guide RNA | Size |
|---|---|
| Alt-R® CRISPR-Cas12a crRNA | 2 and 10 nmol |
Choosing a Cas12a nuclease
The Alt-R CRISPR-Cas12a system allows targeting of alternative sites that are not available to the CRISPR-Cas9 system and produces a staggered cut with a 5’ overhang. Enables genome editing in organisms with AT-rich genomes. Target sequences must contain an adjacent «TTTV» PAM site (V = A, C or G).
| Cat-No. | Nuclease | Size | Comments |
|---|---|---|---|
| 1081068 | Alt-R® A.s. Cas12a (Cpf1) V3 | 100 ug | Wild-type version with strong NLS. High on-target efficiency due to effective delivery to the nucleus. |
| 10001272 | Alt-R® A.s. Cas12a (Cpf1) Ultra | 100 ug | Improved version with increased specificity. High on-target efficiency paired with strongly reduced off-target activity. Use when off-target modifications are of concern. |
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