RNA-guided genetic silencing systems in bacteria and archaea


Clustered regularly interspaced short palindromic repeat (CRISPR) are essential components of nucleic-acid-based adaptive immune systems that are widespread in bacteria and archaea. Similar to RNA interference (RNAi) pathways in eukaryotes, CRISPR-mediated immune systems rely on small RNAs for sequence-specific detection and silencing of foreign nucleic acids, including viruses and plasmids. However, the mechanism of RNA-based bacterial immunity is distinct from RNAi. Understanding how small RNAs are used to find and destroy foreign nucleic acids will provide new insights into the diverse mechanisms of RNA-controlled genetic silencing systems.

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Figure 1: Parallels and distinctions between CRISPR RNA-guided silencing systems and RNAi.
Figure 2: Diversity of CRISPR-mediated adaptive immune systems in bacteria and archaea.
Figure 3: Steps leading to new spacer integration.
Figure 4: Diverse mechanisms of CRISPR RNA biogenesis.


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B.W. is a Howard Hughes Medical Institute Fellow of the Life Sciences Research Foundation. S.H.S. acknowledges support from the National Science Foundation and National Defense Science & Engineering Graduate Research Fellowship programs. J.A.D. is an Investigator of the Howard Hughes Medical Institute.

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Wiedenheft, B., Sternberg, S. & Doudna, J. RNA-guided genetic silencing systems in bacteria and archaea. Nature 482, 331–338 (2012). https://doi.org/10.1038/nature10886

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