RNA activation-independent DNA targeting of the Type III CRISPR-Cas system by a Csm complex.

ABSTRACT: The CRISPR-Cas system is an adaptive and heritable immune response that destroys invading foreign nucleic acids. The effector complex of the Type III CRISPR-Cas system targets RNA and DNA in a transcription-coupled manner, but the exact mechanism of DNA targeting by this complex remains elusive. In this study, an effector Csm holocomplex derived from Thermococcus onnurineus is reconstituted with a minimalistic combination of Csm1₁2₁3₃4₁5₁, and shows RNA targeting and RNA-activated single-stranded DNA (ssDNA) targeting activities. Unexpectedly, in the absence of an RNA transcript, it cleaves ssDNA containing a sequence complementary to the bound crRNA guide region in a manner dependent on the HD domain of the Csm1 subunit. This n

SUBMITTER: Park KH 

PROVIDER: S-EPMC5412804 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature