Widespread anti-CRISPR proteins in virulent bacteriophages inhibit a range of Cas9 proteins.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30046034.
- Also identified by DOI 10.1038/s41467-018-05092-w and PMC identifier 6060171.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
CRISPR-Cas systems are bacterial anti-viral systems, and bacterial viruses (bacteriophages, phages) can carry anti-CRISPR (Acr) proteins to evade that immunity. Acrs can also fine-tune the activity of CRISPR-based genome-editing tools. While Acrs are prevalent in phages capable of lying dormant in a CRISPR-carrying host, their orthologs have been observed only infrequently in virulent phages. Here we identify AcrIIA6, an Acr encoded in 33% of virulent Streptococcus thermophilus phage genomes. The X-ray structure of AcrIIA6 displays some features unique to this Acr family. We compare the activity of AcrIIA6 to those of other Acrs, including AcrIIA5 (also from S. thermophilus phages), and characterize their effectiveness against a range of CRISPR-Cas systems. Finally, we demonstrate that both Acr families from S. thermophilus phages inhibit Cas9-mediated genome editing of human cells.
Medical subject headings
- CRISPR-Associated Protein 9
- Clustered Regularly Interspaced Short Palindromic Repeats