CRISPR/Cas9 gene editing

Article By:

Chen, Wenbiao Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.

Page-McCaw, Patrick S. Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee.

Last reviewed:January 2022

DOI:https://doi.org/10.1036/1097-8542.168060

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• CRISPR/Cas9 gene editing, published June 2014:Download PDF Get Adobe Acrobat Reader

A genome-engineering technique that allows precise targeting of specific stretches of genetic code and editing of DNA at designated locations. The CRISPR/Cas9 system has been used as a general tool to engineer the genomes of many different organisms; the system is derived from naturally occurring components of a common prokaryotic immune system. Clustered regularly interspaced short palindromic repeats (CRISPRs) and cas9 are genes found in Bacteria and Archaea, and they mediate immunity in these species (Fig. 1). The cas9 gene encodes a deoxyribonucleic acid (DNA)–cutting enzyme, whereas the CRISPR gene encodes many ribonucleic acid (RNA) cofactors on the Cas9 enzyme. These RNA cofactors provide specificity to the enzyme. Just 20 nucleotides of these RNA cofactors mediate DNA-cleavage specificity, and these nucleotides can be modified by the user to create new specificities. If DNA cleavage occurs in eukaryotic cells, the cleaved DNA is repaired through an error-prone mechanism called nonhomologous end-joining. Nonhomologous end-joining introduces mutations in the genomic DNA, altering the target gene's function in ways that are useful to the geneticist or genetic engineer. See also: Archaea; Bacteria; CRISPR-based immunity in prokaryotes; CRISPR genome-editing methods against superbugs; Deoxyribonucleic acid (DNA); DNA repair; Enzyme; Gene; Genetic code; Genetic engineering; Genetics; Genomics; Mutation; Nucleotide; Ribonucleic acid (RNA)

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