Ring nucleases deactivate type III CRISPR ribonucleases by degrading cyclic oligoadenylate.

ABSTRACT: The CRISPR system provides adaptive immunity against mobile genetic elements in prokaryotes, using small CRISPR RNAs that direct effector complexes to degrade invading nucleic acids^1-3. Type III effector complexes were recently demonstrated to synthesize a novel second messenger, cyclic oligoadenylate, on binding target RNA^4,5. Cyclic oligoadenylate, in turn, binds to and activates ribonucleases and other factors-via a CRISPR-associated Rossman-fold domain-and thereby induces in the cell an antiviral state that is important for immunity. The mechanism of the 'off-switch' that resets the system is not understood. Here we identify the nuclease that degrades these cyclic oligoadenylate ring molecules. This 'ring nuclease' is itself a protein of the CRISPR-associated Ross

SUBMITTER: Athukoralage JS 

PROVIDER: S-EPMC6219705 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature