CRISPR Clustered Regularly Interspaced Short

CRISPR clustered regularly interspaced short palindromic repeats... 

The first antiviral defense. While the ribosomes might have had precellular ribozyme-based ancestors in the primordial virus world, for the assemblage of the CRISPR/CAS/CASCADE system (clustered regularly interspaced short palindromic repeats CRISPR-associated complex for antiviral defense), advanced cells (archaea, prokaiyota) were essential. Once established, the valuable CRISPR operons travelling horizontally were avidly accepted. The CRISPR spacers are... 

Lintner NG, Kerou M, Brumfield SK, Graham S, liu H, Naismith JH, Sdano M, Peng N, She Q, Copie V, Young MJ, White M, Lawrence CM. Strucmral and functional characterization of an arehaeal clustered regularly interspaced short palindromic repeat (CRISPR)-associated complex for antiviral defence (CASCADE). J Biol Chem. 2011 286 21643-56. 

Figure 6.2. Natural phage resistance mechanisms described in lactic acid bacteria. R/M restriction/modification systems CRISPR-cas clustered regularly interspaced short palindromic repeats (CRISPR) loci and cas (CRISPR-associated) genes,...

Richter, C., Chang, J.T., and Fineran, P.C. (2012) Function and regulation of clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR associated (Cas) systems. Viruses 4, 2291-2311. 

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