title: RNA-guided RNA cleavage by a CRISPR RNA-Cas protein complex.
abstract: Compelling evidence indicates that the CRISPR-Cas system protects prokaryotes from viruses and other potential genome invaders. This adaptive prokaryotic immune system arises from the clustered regularly interspaced short palindromic repeats (CRISPRs) found in prokaryotic genomes, which harbor short invader-derived sequences, and the CRISPR-associated (Cas) protein-coding genes. Here, we have identified a CRISPR-Cas effector complex that is comprised of small invader-targeting RNAs from the CRISPR loci (termed prokaryotic silencing (psi)RNAs) and the RAMP module (or Cmr) Cas proteins. The psiRNA-Cmr protein complexes cleave complementary target RNAs at a fixed distance from the 3' end of the integral psiRNAs. In Pyrococcus furiosus, psiRNAs occur in two size forms that share a common 5' sequence tag but have distinct 3' ends that direct cleavage of a given target RNA at two distinct sites. Our results indicate that prokaryotes possess a unique RNA silencing system that functions by homology-dependent cleavage of invader RNAs.
authors: Department of Biochemistry, University of Georgia, Athens, GA 30602, USA.
authors: Caryn R
authors: CR
authors: Hale
authors: Peng
authors: P
authors: Zhao
authors: Sara
authors: S
authors: Olson
authors: Michael O
authors: MO
authors: Duff
authors: Brenton R
authors: BR
authors: Graveley
authors: Lance
authors: L
authors: Wells
authors: Rebecca M
authors: RM
authors: Terns
authors: Michael P
authors: MP
authors: Terns
mesh_terms: D019843:Archaeal Proteins / Q000276:immunology* / Q000378:metabolism; D001483:Base Sequence; D020027:Pyrococcus furiosus / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D034622:RNA Interference; D019642:RNA, Archaeal / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D012367:RNA, Viral / Q000276:immunology; D058727:RNA, Small Untranslated
chemical_list: D019843:Archaeal Proteins; D019642:RNA, Archaeal; D012367:RNA, Viral; D058727:RNA, Small Untranslated