Two distinct DNA binding modes guide dual roles of a CRISPR-Cas protein complex.
Mol Cell
; 58(1): 60-70, 2015 Apr 02.
Article
em En
| MEDLINE
| ID: mdl-25752578
ABSTRACT
Small RNA-guided protein complexes play an essential role in CRISPR-mediated immunity in prokaryotes. While these complexes initiate interference by flagging cognate invader DNA for destruction, recent evidence has implicated their involvement in new CRISPR memory formation, called priming, against mutated invader sequences. The mechanism by which the target recognition complex mediates these disparate responses-interference and priming-remains poorly understood. Using single-molecule FRET, we visualize how bona fide and mutated targets are differentially probed by E. coli Cascade. We observe that the recognition of bona fide targets is an ordered process that is tightly controlled for high fidelity. Mutated targets are recognized with low fidelity, which is featured by short-lived and PAM- and seed-independent binding by any segment of the crRNA. These dual roles of Cascade in immunity with distinct fidelities underpin CRISPR-Cas robustness, allowing for efficient degradation of bona fide targets and priming of mutated DNA targets.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA Viral
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Regulação Bacteriana da Expressão Gênica
/
Proteínas de Escherichia coli
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Escherichia coli
/
Proteínas Associadas a CRISPR
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Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas
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Sistemas CRISPR-Cas
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Holanda