Multiple mechanisms for CRISPR-Cas inhibition by anti-CRISPR proteins.
Multiple mechanisms for CRISPR-Cas inhibition by anti-CRISPR proteins.
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DOI：
10.1038/nature15254
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发表时间：
2015-10-01
期刊：
影响因子：
64.8
通讯作者：
Davidson AR
中科院分区：
文献类型：
--
作者：
Bondy-Denomy J;Garcia B;Strum S;Du M;Rollins MF;Hidalgo-Reyes Y;Wiedenheft B;Maxwell KL;Davidson AR
细菌和感染它们的病毒（噬菌体）之间的生存之战导致了许多细菌防御系统和这些系统的噬菌体编码拮抗剂的进化。成簇的规则间隔的短回文重复序列 (CRISPR) 和 CRISPR 相关 (cas) 基因构成了适应性免疫系统，该系统是细菌防御噬菌体的最广泛的手段之一。我们发现了噬菌体产生的抑制 CRISPR-Cas 系统的蛋白质的第一个例子。在这里，我们对其中三种抗 CRISPR 蛋白进行了生化和体内研究，结果表明每种蛋白都通过独特的机制抑制 CRISPR-Cas 活性。其中两种阻断 CRISPR-Cas 复合物的 DNA 结合活性，但通过与不同的蛋白质亚基相互作用并使用空间或非空间抑制模式来实现这一点。第三种抗 CRISPR 蛋白通过与 Cas3 解旋酶-核酸酶结合并阻止其招募至 DNA 结合的 CRISPR-Cas 复合物来发挥作用。在体内，这种抗 CRISPR 可以将 CRISPR-Cas 系统转化为转录抑制子，据我们所知，这提供了第一个通过蛋白质相互作用子调节 CRISPR-Cas 活性的例子。这些抗 CRISPR 蛋白的不同序列和作用机制意味着独立进化，并预示着蛋白质可能改变 CRISPR-Cas 功能的其他方式的存在。
The battle for survival between bacteria and the viruses that infect them (phages) has led to the evolution of many bacterial defence systems and phage-encoded antagonists of these systems. Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated (cas) genes comprise an adaptive immune system that is one of the most widespread means by which bacteria defend themselves against phages. We identified the first examples of proteins produced by phages that inhibit a CRISPR–Cas system. Here we performed biochemical and in vivo investigations of three of these anti-CRISPR proteins, and show that each inhibits CRISPR–Cas activity through a distinct mechanism. Two block the DNA-binding activity of the CRISPR–Cas complex, yet do this by interacting with different protein subunits, and using steric or non-steric modes of inhibition. The third anti-CRISPR protein operates by binding to the Cas3 helicase–nuclease and preventing its recruitment to the DNA-bound CRISPR–Cas complex. In vivo, this anti-CRISPR can convert the CRISPR–Cas system into a transcriptional repressor, providing the first example—to our knowledge—of modulation of CRISPR–Cas activity by a protein interactor. The diverse sequences and mechanisms of action of these anti-CRISPR proteins imply an independent evolution, and foreshadow the existence of other means by which proteins may alter CRISPR–Cas function.