A scoutRNA Is Required for Some Type V CRISPR-Cas Systems.
Mol Cell
; 79(3): 416-424.e5, 2020 08 06.
Article
in En
| MEDLINE
| ID: mdl-32645367
ABSTRACT
CRISPR-Cas12c/d proteins share limited homology with Cas12a and Cas9 bacterial CRISPR RNA (crRNA)-guided nucleases used widely for genome editing and DNA detection. However, Cas12c (C2c3)- and Cas12d (CasY)-catalyzed DNA cleavage and genome editing activities have not been directly observed. We show here that a short-complementarity untranslated RNA (scoutRNA), together with crRNA, is required for Cas12d-catalyzed DNA cutting. The scoutRNA differs in secondary structure from previously described tracrRNAs used by CRISPR-Cas9 and some Cas12 enzymes, and in Cas12d-containing systems, scoutRNA includes a conserved five-nucleotide sequence that is essential for activity. In addition to supporting crRNA-directed DNA recognition, biochemical and cell-based experiments establish scoutRNA as an essential cofactor for Cas12c-catalyzed pre-crRNA maturation. These results define scoutRNA as a third type of transcript encoded by a subset of CRISPR-Cas genomic loci and explain how Cas12c/d systems avoid requirements for host factors including ribonuclease III for bacterial RNA-mediated adaptive immunity.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacteria
/
Bacterial Proteins
/
RNA, Bacterial
/
Genome, Bacterial
/
Endodeoxyribonucleases
/
RNA, Small Untranslated
/
CRISPR-Cas Systems
Language:
En
Journal:
Mol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2020
Type:
Article
Affiliation country:
United States