engleski

Targeting of RNA to DNA by Cas3 protein provides a novel interference mechanism in cas-CRISPR immunity.

Microbial cas-CRISPR systems give immunity against invading nucleic acids that is hypothesised to operate through an RNA interference (RNAi) mechanism. Central to this is trageting of invading DNA or RNA by host CRISPR RNA, but how this is achieved is not known. We have identified that Cas3 catalyses targeting of RNA to DNA in pairing reactions that form bona fide R-loops. Targeting requires a functional HD-motif that is conserved in Cas3 proteins, and involves nicking of DNA and RNA. We found no evidence for helicase or translocase scanning by Cas3, but an ATP-induced conformational change in Cas3 can control RNA-DNA targeting reactions. RNA-DNA pairing by Cas3 explains its requirement for phage resistance in E. coli and might be useful for development as biotechnological tool more generally.

CRISPR; cas3; R-loop

nije evidentirano