title: CRISPR-Cas systems in bacteria and archaea: versatile small RNAs for adaptive defense and regulation.
abstract: Bacteria and archaea have evolved defense and regulatory mechanisms to cope with various environmental stressors, including virus attack. This arsenal has been expanded by the recent discovery of the versatile CRISPR-Cas system, which has two novel features. First, the host can specifically incorporate short sequences from invading genetic elements (virus or plasmid) into a region of its genome that is distinguished by clustered regularly interspaced short palindromic repeats (CRISPRs). Second, when these sequences are transcribed and precisely processed into small RNAs, they guide a multifunctional protein complex (Cas proteins) to recognize and cleave incoming foreign genetic material. This adaptive immunity system, which uses a library of small noncoding RNAs as a potent weapon against fast-evolving viruses, is also used as a regulatory system by the host. Exciting breakthroughs in understanding the mechanisms of the CRISPR-Cas system and its potential for biotechnological applications and understanding evolutionary dynamics are discussed.
authors: Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305, USA. dbhaya@stanford.edu
authors: Devaki
authors: D
authors: Bhaya
authors: Michelle
authors: M
authors: Davison
authors: Rodolphe
authors: R
authors: Barrangou
mesh_terms: D056704:Adaptive Immunity; D001105:Archaea / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000821:virology; D001419:Bacteria / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000821:virology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D001435:Bacteriophages / Q000235:genetics / Q000276:immunology; D064130:CRISPR-Associated Proteins; D019295:Computational Biology; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D019848:Gene Expression Regulation, Archaeal; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D010957:Plasmids / Q000276:immunology; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D019642:RNA, Archaeal / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D058727:RNA, Small Untranslated / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic; D014777:Virus Diseases / Q000235:genetics / Q000276:immunology / Q000821:virology
chemical_list: D001426:Bacterial Proteins; D064130:CRISPR-Associated Proteins; D029968:Escherichia coli Proteins; D019642:RNA, Archaeal; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; D004706:Endodeoxyribonucleases; C557650:YgbT protein, E coli