Send to

Choose Destination
Annu Rev Genet. 2018 Nov 23;52:445-464. doi: 10.1146/annurev-genet-120417-031321. Epub 2018 Sep 12.

Phage-Encoded Anti-CRISPR Defenses.

Author information

Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1, Canada; email:


The battle for survival between bacteria and bacteriophages (phages) is an arms race where bacteria develop defenses to protect themselves from phages and phages evolve counterstrategies to bypass these defenses. CRISPR-Cas adaptive immune systems represent a widespread mechanism by which bacteria protect themselves from phage infection. In response to CRISPR-Cas, phages have evolved protein inhibitors known as anti-CRISPRs. Here, we describe the discovery and mechanisms of action of anti-CRISPR proteins. We discuss the potential impact of anti-CRISPRs on bacterial evolution, speculate on their evolutionary origins, and contemplate the possible next steps in the CRISPR-Cas evolutionary arms race. We also touch on the impact of anti-CRISPRs on the development of CRISPR-Cas-based biotechnological tools.


CRISPR-Cas; Cas9; Cascade; anti-CRISPR; bacteriophage

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center