Type III CRISPR-Cas systems can provide redundancy to counteract viral escape from type I systems.
Elife
; 62017 08 17.
Article
em En
| MEDLINE
| ID: mdl-28826484
ABSTRACT
CRISPR-Cas-mediated defense utilizes information stored as spacers in CRISPR arrays to defend against genetic invaders. We define the mode of target interference and role in antiviral defense for two CRISPR-Cas systems in Marinomonas mediterranea. One system (type I-F) targets DNA. A second system (type III-B) is broadly capable of acquiring spacers in either orientation from RNA and DNA, and exhibits transcription-dependent DNA interference. Examining resistance to phages isolated from Mediterranean seagrass meadows, we found that the type III-B machinery co-opts type I-F CRISPR-RNAs. Sequencing and infectivity assessments of related bacterial and phage strains suggests an 'arms race' in which phage escape from the type I-F system can be overcome through use of type I-F spacers by a horizontally-acquired type III-B system. We propose that the phage-host arms race can drive selection for horizontal uptake and maintenance of promiscuous type III interference modules that supplement existing host type I CRISPR-Cas systems.
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Base de dados:
MEDLINE
Assunto principal:
Marinomonas
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Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas
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Sistemas CRISPR-Cas
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Sistemas de Secreção Tipo I
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Sistemas de Secreção Tipo III
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article