TitleInhibition of CRISPR-Cas9 with Bacteriophage Proteins.
Publication TypeJournal Article
Year of Publication2017
AuthorsRauch BJ, Silvis MR, Hultquist JF, Waters CS, McGregor MJ, Krogan NJ, Bondy-Denomy J
Date Published2017 Jan 12
KeywordsBacterial Proteins, Bacteriophages, CRISPR-Cas Systems, Endonucleases, Escherichia coli, Genetic Engineering, HEK293 Cells, Humans, Listeria monocytogenes, Prophages

Bacterial CRISPR-Cas systems utilize sequence-specific RNA-guided nucleases to defend against bacteriophage infection. As a countermeasure, numerous phages are known that produce proteins to block the function of class 1 CRISPR-Cas systems. However, currently no proteins are known to inhibit the widely used class 2 CRISPR-Cas9 system. To find these inhibitors, we searched cas9-containing bacterial genomes for the co-existence of a CRISPR spacer and its target, a potential indicator for CRISPR inhibition. This analysis led to the discovery of four unique type II-A CRISPR-Cas9 inhibitor proteins encoded by Listeria monocytogenes prophages. More than half of L. monocytogenes strains with cas9 contain at least one prophage-encoded inhibitor, suggesting widespread CRISPR-Cas9 inactivation. Two of these inhibitors also blocked the widely used Streptococcus pyogenes Cas9 when assayed in Escherichia coli and human cells. These natural Cas9-specific "anti-CRISPRs" present tools that can be used to regulate the genome engineering activities of CRISPR-Cas9.

Alternate JournalCell
PubMed ID28041849
PubMed Central IDPMC5235966
Grant ListT32 GM007810 / GM / NIGMS NIH HHS / United States
T32 AI060537 / AI / NIAID NIH HHS / United States
DP5 OD021344 / OD / NIH HHS / United States
P50 GM082250 / GM / NIGMS NIH HHS / United States
U19 AI118610 / AI / NIAID NIH HHS / United States
P30 AI027763 / AI / NIAID NIH HHS / United States