CRISPR-Cas type I-A Cascade complex couples viral infection surveillance to host transcriptional regulation in the dependence of Csa3b

TY - JOUR

T1 - CRISPR-Cas type I-A Cascade complex couples viral infection surveillance to host transcriptional regulation in the dependence of Csa3b

AU - He, Fei

AU - Vestergaard, Gisle Alberg

AU - Peng, Wenfang

AU - She, Qunxin

AU - Peng, Xu

PY - 2017/2/28

Y1 - 2017/2/28

N2 - 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.

AB - 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.

U2 - 10.1093/nar/gkw1265

DO - 10.1093/nar/gkw1265

M3 - Journal article

C2 - 27980065

SN - 0305-1048

VL - 45

SP - 1902

EP - 1913

JO - Nucleic Acids Research

JF - Nucleic Acids Research

IS - 4

ER -