Selective degradation of phage RNAs by the Csm6 ribonuclease provides robust type III CRISPR immunity in Streptococcus thermophilus.

Autor:	Johnson KA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA., Garrett SC; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT, USA., Noble-Molnar C; Department of Microbiology, University of Georgia, Athens, GA, USA., Elgarhi HA; Department of Genetics, University of Georgia, Athens, GA, USA., Woodside WT; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA., Cooper C; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA., Zhang X; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA., Olson S; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT, USA., Catchpole RJ; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA., Graveley BR; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT, USA., Terns MP; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.; Department of Microbiology, University of Georgia, Athens, GA, USA.; Department of Genetics, University of Georgia, Athens, GA, USA.
Jazyk:	angličtina
Zdroj:	Nucleic acids research [Nucleic Acids Res] 2024 Oct 03. Date of Electronic Publication: 2024 Oct 03.
DOI:	10.1093/nar/gkae856
Abstrakt:	Type III CRISPR immune systems bind viral or plasmid RNA transcripts and activate Csm3/Cmr4 and Cas10 nucleases to uniquely cleave both invader RNA and DNA, respectively. Additionally, type III effector complexes generate cyclic oligoadenylate (cOA) signaling molecules to activate trans-acting, auxiliary Csm6/Csx1 ribonucleases, previously proposed to be non-specific in their in vivo RNA cleavage preference. Despite extensive in vitro studies, the nuclease requirements of type III systems in their native contexts remain poorly understood. Here we systematically investigated the in vivo roles for immunity of each of the three Streptococcus thermophilus (Sth) type III-A Cas nucleases and cOA signaling by challenging nuclease defective mutant strains with plasmid and phage infections. Our results reveal that RNA cleavage by Csm6 is both sufficient and essential for maintaining wild-type levels of immunity. Importantly, Csm6 RNase activity leads to immunity against even high levels of phage challenge without causing host cell dormancy or death. Transcriptomic analyses during phage infection indicated Csm6-mediated and crRNA-directed preferential cleavage of phage transcripts. Our findings highlight the critical role of Csm6 RNase activity in type III immunity and demonstrate specificity for invader RNA transcripts by Csm6 to ensure host cell survival upon phage infection. (© The Author(s) 2024. Published by Oxford University Press on behalf of Nucleic Acids Research.)
Databáze:	MEDLINE
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