Function and Regulation of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) / CRISPR Associated (Cas) Systems

Viruses

Corinna Richter¹  James T. Chang¹ 

[1] Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand;

关键词: phages;    plasmids;    horizontal gene transfer;    CRISPR;    Cas;    cascade;    PAM;    crRNA;    resistance;   

DOI  :  10.3390/v4102291

来源: mdpi

【 摘 要 】

Phages are the most abundant biological entities on earth and pose a constant challenge to their bacterial hosts. Thus, bacteria have evolved numerous ‘innate’ mechanisms of defense against phage, such as abortive infection or restriction/modification systems. In contrast, the clustered regularly interspaced short palindromic repeats (CRISPR) systems provide acquired, yet heritable, sequence-specific ‘adaptive’ immunity against phage and other horizontally-acquired elements, such as plasmids. Resistance is acquired following viral infection or plasmid uptake when a short sequence of the foreign genome is added to the CRISPR array. CRISPRs are then transcribed and processed, generally by CRISPR associated (Cas) proteins, into short interfering RNAs (crRNAs), which form part of a ribonucleoprotein complex. This complex guides the crRNA to the complementary invading nucleic acid and targets this for degradation. Recently, there have been rapid advances in our understanding of CRISPR/Cas systems. In this review, we will present the current model(s) of the molecular events involved in both the acquisition of immunity and interference stages and will also address recent progress in our knowledge of the regulation of CRISPR/Cas systems.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.