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Type III CRISPR-Cas provides resistance against nucleus-forming jumbo phages via abortive infection
Bacteria have diverse defenses against phages. In response, jumbo phages evade multiple DNA-targeting defenses by protecting their DNA inside a nucleus-like structure. We previously demonstrated that RNA-targeting type III CRISPR-Cas systems provide jumbo phage immunity by recognizing viral mRNA exp...
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Published in: | Molecular cell 2022-12, Vol.82 (23), p.4471-4486.e9 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Bacteria have diverse defenses against phages. In response, jumbo phages evade multiple DNA-targeting defenses by protecting their DNA inside a nucleus-like structure. We previously demonstrated that RNA-targeting type III CRISPR-Cas systems provide jumbo phage immunity by recognizing viral mRNA exported from the nucleus for translation. Here, we demonstrate that recognition of phage mRNA by the type III system activates a cyclic triadenylate-dependent accessory nuclease, NucC. Although unable to access phage DNA in the nucleus, NucC degrades the bacterial chromosome, triggers cell death, and disrupts phage replication and maturation. Hence, type-III-mediated jumbo phage immunity occurs via abortive infection, with suppression of the viral epidemic protecting the population. We further show that type III systems targeting jumbo phages have diverse accessory nucleases, including RNases that provide immunity. Our study demonstrates how type III CRISPR-Cas systems overcome the inaccessibility of jumbo phage DNA to provide robust immunity.
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•Type III CRISPR-Cas provides immunity against nucleus-forming jumbo phages•Type III recognition of jumbo phage mRNA activates the accessory DNase NucC•NucC degrades the bacterial DNA, triggering cell death to prevent phage replication•Abortive infection protects the clonal population by suppressing the viral epidemic
Mayo-Muñoz et al. uncover how RNA-targeting type III CRISPR-Cas systems protect bacteria from jumbo phages that form nucleus-like “shields” during infection to protect their genomes. This study demonstrates how a type III accessory nuclease (NucC) elicits abortive infection and its role in type III phage defense. |
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ISSN: | 1097-2765 1097-4164 |
DOI: | 10.1016/j.molcel.2022.10.028 |