Co-occurrence of multiple CRISPRs and cas clusters suggests epistatic interactions
Co-occurrence of multiple CRISPRs and cas clusters suggests epistatic interactions
复制标题
多个 CRISPR 和 cas 簇的共现表明上位相互作用
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
E. Rocha
中科院分区：
文献类型：
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作者：
A. Bernheim;David Bikard;M. Touchon;E. Rocha
原核生物使用CRISPR-Cas进行适应性免疫，但对存在多个CRISPR和cas簇的原因仍然知之甚少。我们发现，超过40%的编码系统的基因组显示出非典型的遗传组织。他们的分析揭示了Cas亚型之间的负上位和正上位相互作用。后者通常导致一个单一的复杂基因座，具有共享的适应模块和不同的干扰机制，可能是为了产生更有效的免疫系统。我们对不能与cas簇明确相关的CRISPR进行了分型，并发现这种复杂的基因座往往在多个CRISPR中具有独特的I型重复序列。相比之下，由功能干扰或冗余引起的代表性不足的共存可能会导致CRISPR远离cas基因。为了研究非典型CRISPR-Cas组织的起源，我们分析了质粒和DNA。近2000个噬菌体和10000个噬菌体的集合几乎没有CRISPR-Cas系统，但相当大一部分质粒具有它们。质粒中分离的CRISPR通常与染色体cas簇相容，这表明质粒使用CRISPR来破坏宿主免疫力。这些结果指出了多种CRISPR和Cas之间的相互作用在细菌免疫功能和进化中的重要作用。
Prokaryotes use CRISPR-Cas for adaptive immunity, but the reasons for the existence of multiple CRISPR and cas clusters remain poorly understood. We found that more than 40% of the genomes encoding a system show atypical genetic organizations. Their analysis revealed negative and positive epistatic interactions between Cas subtypes. The latter often result in one single complex locus with a shared adaptation module and diverse interference mechanisms, presumably to produce more effective immune systems. We typed CRISPRs that could not be unambiguously associated with a cas cluster and found that such complex loci tend to have unique type I repeats in multiple CRISPRs. In contrast, under-represented co-occurrences caused by functional interference or redundancy may lead to CRISPRs distant from cas genes. To investigate the origin of atypical CRISPR-Cas organizations, we analyzed plasmids and phages. Sets of nearly 2000 phages and 10000 prophages were almost devoid of CRISPR-Cas systems, but a sizeable fraction of plasmids had them. Isolated CRISPRs in plasmids were often compatible with the chromosomal cas clusters, suggesting that plasmids use CRISPRs to subvert host immunity. These results point to an important role for the interactions between multiple CRISPR and Cas in the function and evolution of bacterial immunity.
影响因子：
14.9
作者：
Makarova, KS;Aravind, L;Koonin, EV
通讯作者：
Koonin, EV
影响因子：
11.4
作者：
Stern, Adi;Keren, Leeat;Wurtzel, Omri;Amitai, Gil;Sorek, Rotem
通讯作者：
Sorek, Rotem