| Term | Description |
|---|---|
| CAS9 | CRISPR-associated protein 9 (Cas9) nuclease. To initiate programmed DNA targeting, Cas9 binds both crRNA and tracrRNA in an RNA-duplex. The first 20 nucleotides of the crRNA guide Cas9 to cleave any complementary genomic sequence located next to a short protospacer adjacent motif (PAM). A convenient fusion of the crRNA and tracrRNA produces a chimeric single guide RNA (sgRNA) that is sufficient to target Cas9 as well. Cas9 isolated from the bacteria Streptococcus pyogenes (SpCas9) is most commonly used in CRISPR screens currently and the CAS9 variants discussed below should be assumed to be SpCas9 unless otherwise noted. (PMID: 27248712) |
| dCAS9 | A nuclease ‘dead’ Cas9 (dCas9) variant, this is able to bind DNA in a sequence specific manner but not cleave it. |
| dCas9-VP64 | dCas9 fusions to VP64 activator (four tandem repeats of the herpes simplex virus protein 16, VP16). |
| SunCas9 | SUperNova tagging (SunTag) system employs 10 repeats of a short epitope tag fused directly to dCas9, allowing in trans expression and recruitment of 10 single-chain variable fragments (scFvs) fused to VP64. |
| SAM | Synergistic activation mediator (SAM) system incorporates two MS2 hairpins into the sgRNA and fuses MCP to a novel chimeric activator p65-HSF1. The chimeric MCP-p65-HSF1 activators bind each MS2 hairpin as a set of homodimers, resulting in four copies of MCP-p65-HSF1 scaffolding onto the SAM sgRNA, bound to dCas9-VP64. Also known as NLS-dCas9-VP64/MS2-p65-HSF1. |
| dCas9-KRAB | Fusion of the Kruppel-associated box (KRAB) domain of Kox1 to dCas9, leading to recruitment of chromatin modifying complexes which silence transcription. |
| CPF1 | Cpf1 is a single RNA-guided endonuclease lacking tracrRNA, and it utilizes a T-rich protospacer-adjacent motif. Cpf1 cleaves DNA via a staggered DNA double-stranded break. |
| CAS13a | Class 2 type VI RNA-guided RNA-targeting CRISPR–Cas effector which can be engineered for mammalian cell RNA knockdown and binding. |
| AncBE4max | Cytidine base editor that converts target C:G base pairs to T:A, introducing point mutations instead of double strand breaks at target. These point mutations can be used to induce gene KO by introducing premature termination codons or splicing disruptions. AncBE4max has a bis-bpNLS BE4 with the Anc689 APOBEC and GenScript codons. |