Structural basis of cyclic oligoadenylate binding to the transcription factor Csa3 outlines cross talk between type III and type I CRISPR systems.

ABSTRACT: RNA interference by type III CRISPR systems results in the synthesis of cyclic oligoadenylate (cOA) second messengers, which are known to bind and regulate various CARF domain-containing nuclease receptors. The CARF domain-containing Csa3 family of transcriptional factors associated with the DNA-targeting type I CRISPR systems regulate expression of various CRISPR and DNA repair genes in many prokaryotes. In this study, we extend the known receptor repertoire of cOA messengers to include transcriptional factors by demonstrating specific binding of cyclic tetra-adenylate (cA4) to Saccharolobus solfataricus Csa3 (Csa3_Sso). Our 2.0-Å resolution X-ray crystal structure of cA4-bound full-length Csa3_Sso reveals the binding of its CARF domain to an elongated conformation of

SUBMITTER: Xia P 

PROVIDER: S-EPMC8844856 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature