The diversity-generating benefits of a prokaryotic adaptive immune system.
The diversity-generating benefits of a prokaryotic adaptive immune system.
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DOI：
10.1038/nature17436
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发表时间：
2016-04-21
期刊：
影响因子：
64.8
通讯作者：
Westra ER
中科院分区：
文献类型：
--
作者：
van Houte S;Ekroth AK;Broniewski JM;Chabas H;Ashby B;Bondy-Denomy J;Gandon S;Boots M;Paterson S;Buckling A;Westra ER
Proximity CRISPR-Cas适应性免疫系统将源自病毒和其他寄生DNA元件的间隔区插入CRISPR基因座中，以提供序列特异性免疫。这通常会导致高种群内的间隔区多样性，但目前还不清楚这是否重要以及为什么重要。在这里，我们表明，由于这种间隔区多样性，病毒不再能够通过点突变来克服CRISPR-Cas，这导致病毒快速灭绝。这种效应源于间隔区多样性和感染的高特异性之间的协同作用，这极大地增加了总体群体抗性。我们认为，CRISPR依赖的细菌-病毒协同进化的短暂性质为复杂的病毒编码的抗CRISPR机制的进化提供了强有力的选择。
Prokaryotic CRISPR-Cas adaptive immune systems insert spacers derived from viruses and other parasitic DNA elements into CRISPR loci to provide sequence-specific immunity. This frequently results in high within-population spacer diversity, but it is unclear if and why this is important. Here we show that, as a result of this spacer diversity, viruses can no longer evolve to overcome CRISPR-Cas by point mutation, which results in rapid virus extinction. This effect arises from synergy between spacer diversity and the high specificity of infection, which greatly increases overall population resistance. We propose that the resulting short-lived nature of CRISPR-dependent bacteria–virus coevolution has provided strong selection for the evolution of sophisticated virus-encoded anti-CRISPR mechanisms.