Bipartite recognition of target RNAs activates DNA cleavage by the Type III-B CRISPR-Cas system.

ABSTRACT: CRISPR-Cas systems eliminate nucleic acid invaders in bacteria and archaea. The effector complex of the Type III-B Cmr system cleaves invader RNAs recognized by the CRISPR RNA (crRNA ) of the complex. Here we show that invader RNAs also activate the Cmr complex to cleave DNA. As has been observed for other Type III systems, Cmr eliminates plasmid invaders in Pyrococcus furiosus by a mechanism that depends on transcription of the crRNA target sequence within the plasmid. Notably, we found that the target RNA per se induces DNA cleavage by the Cmr complex in vitro. DNA cleavage activity does not depend on cleavage of the target RNA but notably does require the presence of a short sequence adjacent to the target sequence within the activating target RNA (rPAM [RNA protospacer-adjacent motif])

SUBMITTER: Elmore JR 

PROVIDER: S-EPMC4762429 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature