The dynamic interplay of host and viral enzymes in type III CRISPR-mediated cyclic nucleotide signalling
The dynamic interplay of host and viral enzymes in type III CRISPR-mediated cyclic nucleotide signalling
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DOI：
10.1101/2020.02.12.946046
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发表时间：
2020-02
期刊：
影响因子：
7.7
通讯作者：
Januka S. Athukoralage;S. Graham;Christophe Rouillon;S. Grüschow;C. Czekster;M. F. White
中科院分区：
文献类型：
--
作者：
Januka S. Athukoralage;S. Graham;Christophe Rouillon;S. Grüschow;C. Czekster;M. F. White
环核苷酸第二信使越来越多地参与原核抗病毒防御系统。 III型CRISPR系统在检测到外源RNA后合成环状寡腺苷酸（cOA），激活可能对细胞有毒的辅助核酸酶，从而需要在通过免疫而不是流产感染运作的系统中去除cOA的机制。此前，我们证明硫磺菌 III-D 型 CRISPR 复合物产生环状四腺苷酸 (cA4)，激活核糖核酸酶 Csx1，并表明随后的 RNA 裂解和解离充当环化酶活性的“关闭开关”(Rouillon et al., 2018)。随后，我们鉴定了细胞环状核酸酶 Crn1，它会缓慢降解 cA4 以重置系统，并证明病毒可以通过有效的抗 CRISPR 环状核酸酶变体颠覆 III 型 CRISPR 免疫。在这里，我们对这些酶之间的动态相互作用进行了全面分析，控制着病毒与宿主冲突中的环核苷酸水平和感染结果。
Cyclic nucleotide second messengers are increasingly implicated in prokaryotic anti-viral defence systems. Type III CRISPR systems synthesise cyclic oligoadenylate (cOA) upon detecting foreign RNA, activating ancillary nucleases that can be toxic to cells, necessitating mechanisms to remove cOA in systems that operate via immunity rather than abortive infection. Previously, we demonstrated that the Sulfolobus solfataricus type III-D CRISPR complex generates cyclic tetra-adenylate (cA4), activating the ribonuclease Csx1, and showed that subsequent RNA cleavage and dissociation acts as an “off-switch” for the cyclase activity (Rouillon et al., 2018). Subsequently, we identified the cellular ring nuclease Crn1, which slowly degrades cA4 to reset the system, and demonstrated that viruses can subvert type III CRISPR immunity by means of a potent anti-CRISPR ring nuclease variant. Here, we present a comprehensive analysis of the dynamic interplay between these enzymes, governing cyclic nucleotide levels and infection outcomes in virus-host conflict.