The CRISPR conundrum: evolve and maybe die, or survive and risk stagnation
Authors:Jesús García-Martínez1, Rafael D. Maldonado1, Noemí M. Guzmán1 and Francisco J. M. Mojica1,2
1 Departamento de Fisiología, Genética y Microbiología. Universidad de Alicante, Campus de San Vicente, 03690 San Vicente del Raspeig (Alicante), Spain.
2 I.M.E.M. Ramón Margalef. Universidad de Alicante, Campus de San Vicente, 03690 San Vicente del Raspeig (Alicante), Spain.
Keywords:
CRISPR, Cas, prokaryotic adaptive immunity, horizontal gene transfer, prokaryotic evolution
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Conflict of interest statement:
The authors have no conflict of interests to declare.
Please cite this article as:
Jesús García-Martínez, Rafael D. Maldonado, Noemí M. Guzmán and Francisco J. M. Mojica (2018). The CRISPR conundrum: evolve and maybe die, or survive and risk stagnation. Microbial Cell 5(6): 262-268. doi: 10.15698/mic2018.06.634
© 2018 García-Martínez et al. This is an open-access article released under the terms of the Creative Commons Attribution (CC BY) license, which allows the unrestricted use, distribution, and reproduction in any medium, provided the original author and source are acknowledged.
Abstract:
CRISPR-Cas represents a prokaryotic defense mechanism against invading genetic elements. Although there is a diversity of CRISPR-Cas systems, they all share similar, essential traits. In general, a CRISPR-Cas system consists of one or more groups of DNA repeats named CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats), regularly separated by unique sequences referred to as spacers, and a set of functionally associated cas (CRISPR associated) genes typically located next to one of the repeat arrays. The origin of spacers is in many cases unknown but, when ascertained, they usually match foreign genetic molecules. The proteins encoded by some of the cas genes are in charge of the incorporation of new spacers upon entry of a genetic element. Other Cas proteins participate in generating CRISPR-spacer RNAs and perform the task of destroying nucleic acid molecules carrying sequences similar to the spacer. In this way, CRISPR-Cas provides protection against genetic intruders that could substantially affect the cell viability, thus acting as an adaptive immune system. However, this defensive action also hampers the acquisition of potentially beneficial, horizontally transferred genes, undermining evolution. Here we cover how the model bacterium Escherichia coli deals with CRISPR-Cas to tackle this major dilemma, evolution versus survival.
doi: 10.15698/mic2018.06.634
Volume 5, pp. 262 to 268, published 16/05/2018.