Anti-CRISPR-Associated Proteins Are Crucial Repressors of Anti-CRISPR Transcription.
Cell
; 178(6): 1452-1464.e13, 2019 09 05.
Article
en En
| MEDLINE
| ID: mdl-31474367
ABSTRACT
Phages express anti-CRISPR (Acr) proteins to inhibit CRISPR-Cas systems that would otherwise destroy their genomes. Most acr genes are located adjacent to anti-CRISPR-associated (aca) genes, which encode proteins with a helix-turn-helix DNA-binding motif. The conservation of aca genes has served as a signpost for the identification of acr genes, but the function of the proteins encoded by these genes has not been investigated. Here we reveal that an acr-associated promoter drives high levels of acr transcription immediately after phage DNA injection and that Aca proteins subsequently repress this transcription. Without Aca activity, this strong transcription is lethal to a phage. Our results demonstrate how sufficient levels of Acr proteins accumulate early in the infection process to inhibit existing CRISPR-Cas complexes in the host cell. They also imply that the conserved role of Aca proteins is to mitigate the deleterious effects of strong constitutive transcription from acr promoters.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Bacteriófagos
/
Proteínas Virales
/
Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas
/
Sistemas CRISPR-Cas
Tipo de estudio:
Prognostic_studies
/
Risk_factors_studies
Idioma:
En
Año:
2019
Tipo del documento:
Article