title: Characterization of the CRISPR/Cas subtype I-A system of the hyperthermophilic crenarchaeon Thermoproteus tenax.
abstract: CRISPR (clustered regularly interspaced short palindromic repeats) elements and cas (CRISPR-associated) genes are widespread in Bacteria and Archaea. The CRISPR/Cas system operates as a defense mechanism against mobile genetic elements (i.e., viruses or plasmids). Here, we investigate seven CRISPR loci in the genome of the crenarchaeon Thermoproteus tenax that include spacers with significant similarity not only to archaeal viruses but also to T. tenax genes. The analysis of CRISPR RNA (crRNA) transcription reveals transcripts of a length between 50 and 130 nucleotides, demonstrating the processing of larger crRNA precursors. The organization of identified cas genes resembles CRISPR/Cas subtype I-A, and the core cas genes are shown to be arranged on two polycistronic transcripts: cascis (cas4, cas1/2, and csa1) and cascade (csa5, cas7, cas5a, cas3, cas3', and cas8a2). Changes in the environmental parameters such as UV-light exposure or high ionic strength modulate cas gene transcription. Two reconstitution protocols were established for the production of two discrete multipartite Cas protein complexes that correspond to their operonic gene arrangement. These data provide insights into the specialized mechanisms of an archaeal CRISPR/Cas system and allow selective functional analyses of Cas protein complexes in the future.
authors.affiliation: Institute of Biology, Microbiology I, University of Duisburg-Essen, Essen, Germany. andre.plagens@mpi-marburg.mpg.de
authors.forename: André
authors.initials: A
authors.lastname: Plagens
authors.forename: Britta
authors.initials: B
authors.lastname: Tjaden
authors.forename: Anna
authors.initials: A
authors.lastname: Hagemann
authors.forename: Lennart
authors.initials: L
authors.lastname: Randau
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hensel
mesh_terms: D000222:Adaptation, Physiological; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001435:Bacteriophages; D003001:Cloning, Molecular; D003470:Culture Media; D019848:Gene Expression Regulation, Archaeal / Q000502:physiology*; D022761:Gene Transfer, Horizontal; D055029:Inverted Repeat Sequences / Q000235:genetics*; D009994:Osmolar Concentration; D041542:Thermoproteus / Q000502:physiology*; D014466:Ultraviolet Rays
chemical_list: D019843:Archaeal Proteins; D003470:Culture Media