1. The CRISPRs, they are a-changin': how prokaryotes generate adaptive immunity.
- Author
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Westra ER, Swarts DC, Staals RH, Jore MM, Brouns SJ, and van der Oost J
- Subjects
- Amino Acid Motifs, Bacteriophages genetics, Bacteriophages immunology, Bacteriophages pathogenicity, CRISPR-Associated Proteins, DNA Helicases genetics, DNA, Viral genetics, DNA, Viral metabolism, Deoxyribonucleases, Type I Site-Specific genetics, Deoxyribonucleases, Type I Site-Specific metabolism, Endodeoxyribonucleases genetics, Escherichia coli K12 genetics, Escherichia coli K12 metabolism, Escherichia coli K12 virology, Escherichia coli Proteins genetics, Genes, Bacterial, Lysogeny, Prophages genetics, Prophages metabolism, Species Specificity, Virus Internalization, DNA Helicases metabolism, Endodeoxyribonucleases metabolism, Escherichia coli K12 immunology, Escherichia coli Proteins metabolism, Gene Expression Regulation, Bacterial
- Abstract
All organisms need to continuously adapt to changes in their environment. Through horizontal gene transfer, bacteria and archaea can rapidly acquire new traits that may contribute to their survival. However, because new DNA may also cause damage, removal of imported DNA and protection against selfish invading DNA elements are also important. Hence, there should be a delicate balance between DNA uptake and DNA degradation. Here, we describe prokaryotic antiviral defense systems, such as receptor masking or mutagenesis, blocking of phage DNA injection, restriction/modification, and abortive infection. The main focus of this review is on CRISPR (clustered regularly interspaced short palindromic repeats)/Cas (CRISPR-associated), a prokaryotic adaptive immune system. Since its recent discovery, our biochemical understanding of this defense system has made a major leap forward. Three highly diverse CRISPR/Cas types exist that display major structural and functional differences in their mode of generating resistance against invading nucleic acids. Because several excellent recent reviews cover all CRISPR subtypes, we mainly focus on a detailed description of the type I-E CRISPR/Cas system of the model bacterium Escherichia coli K12.
- Published
- 2012
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