CRISPR-Cas type I-A Cascade complex couples viral infection surveillance to host transcriptional regulation in the dependence of Csa3b.
Nucleic Acids Res
; 45(4): 1902-1913, 2017 02 28.
Article
in En
| MEDLINE
| ID: mdl-27980065
ABSTRACT
CRISPR-Cas (clustered regularly interspaced short palindromic repeats and the associated genes) constitute adaptive immune systems in bacteria and archaea and they provide sequence specific immunity against foreign nucleic acids. CRISPR-Cas systems are activated by viral infection. However, little is known about how CRISPR-Cas systems are activated in response to viral infection or how their expression is controlled in the absence of viral infection. Here, we demonstrate that both the transcriptional regulator Csa3b, and the type I-A interference complex Cascade, are required to transcriptionally repress the interference gene cassette in the archaeon Sulfolobus. Csa3b binds to two palindromic repeat sites in the promoter region of the cassette and facilitates binding of the Cascade to the promoter region. Upon viral infection, loading of Cascade complexes onto crRNA-matching protospacers leads to relief of the transcriptional repression. Our data demonstrate a mechanism coupling CRISPR-Cas surveillance of protospacers to transcriptional regulation of the interference gene cassette thereby allowing a fast response to viral infection.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Transcription, Genetic
/
Sulfolobus
/
Archaeal Proteins
/
Gene Expression Regulation, Archaeal
/
CRISPR-Associated Proteins
/
CRISPR-Cas Systems
Type of study:
Screening_studies
Language:
En
Journal:
Nucleic Acids Res
Year:
2017
Type:
Article
Affiliation country:
Denmark