@Article{Cass_Haas_Stoll-The_role_Cas-2015,
  author =	 {Cass, Simon D. B. and Haas, Karina A. and Stoll, Britta and 
                  Alkhnbashi, Omer and Sharma, Kundan and Urlaub, Henning and 
                  Backofen, Rolf and Marchfelder, Anita and Bolt, Edward L.},
  title =	 {The role of {Cas8} in type {I} {CRISPR} interference},
  journal =	 {Biosci Rep},
  year =	 {2015},
  volume =	 {35},
  number =	 {4},
  pages =	 {e00197},
  user =	 {alkhanbo},
  pmid =	 {25940458},
  doi = 	 {10.1042/BSR20150043},
  issn = 	 {0144-8463},
  issn = 	 {1573-4935},
  abstract =	 {CRISPR (Clustered Regularly Interspaced Short Palindromic 
                  Repeat) systems provide bacteria and archaea with adaptive 
                  immunity to repel invasive genetic elements. Type I systems 
                  use "Cascade" ribonucleoprotein complexes to target invader 
                  DNA, by base pairing CRISPR RNA (crRNA) to protospacers. 
                  Cascade identifies PAMs (Protospacer Adjacent Motifs) on 
                  invader DNA, triggering R-loop formation and subsequent DNA 
                  degradation by Cas3. Cas8 is a candidate PAM recognition 
                  factor in some Cascades. We analysed Cas8 homologues from 
                  type IB CRISPR systems in archaea Haloferax volcanii (Hvo) 
                  and Methanothermobacter thermautotrophicus (Mth). Cas8 was 
                  essential for CRISPR interference in Hvo, and purified Mth 
                  Cas8 protein responded to PAM sequence when binding to 
                  nucleic acids. Cas8 interacted physically with 
                  Cas5-Cas7-crRNA complex, stimulating binding to PAM 
                  containing substrates. Mutation of conserved Cas8 amino acid 
                  residues abolished interference in vivo, and altered 
                  catalytic activity of Cas8 protein in vitro. This is 
                  experimental evidence that Cas8 is important for targeting 
                  Cascade to invader DNA.}
}