title: Diversity of CRISPR systems in the euryarchaeal Pyrococcales.
abstract: Pyrococcales are members of the order Thermococcales, a group of hyperthermophilic euryarchaea that are frequently found in deep sea hydrothermal vents. Infectious genetic elements, such as plasmids and viruses, remain a threat even in this remote environment and these microorganisms have developed several ways to fight their genetic invaders. Among these are the recently discovered CRISPR systems. In this review, we have combined and condensed available information on genetic elements infecting the Thermococcales and on the multiple CRISPR systems found in the Pyrococcales to fight them. Their organization and mode of action will be presented with emphasis on the Type III-B system that is the only CRISPR system known to target RNA molecules in a process reminiscent of RNA interference. The intriguing case of Pyrococcus abyssi, which is among the rare strains to present a CRISPR system devoid of the universal cas1 and cas2 genes, is also discussed.
authors: Laboratoire de Biochimie, UMR CNRS 7654, Département de Biologie, Ecole Polytechnique, Palaiseau, France.
authors: Cédric
authors: C
authors: Norais
authors: Annick
authors: A
authors: Moisan
authors: Christine
authors: C
authors: Gaspin
authors: Béatrice
authors: B
authors: Clouet-d'Orval
mesh_terms: D023641:Archaeal Viruses / Q000235:genetics / Q000502:physiology; D064113:CRISPR-Cas Systems; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D019848:Gene Expression Regulation, Archaeal; D022761:Gene Transfer, Horizontal; D020745:Genome, Archaeal; D010802:Phylogeny; D043903:Pyrococcus abyssi / Q000235:genetics* / Q000821:virology*; D019709:Thermococcales / Q000235:genetics* / Q000821:virology*
keywords: CRISPR; Cas; Pyrococcales; Thermococcales; hyperthermophiles; virus