Type IV CRISPR-Cas systems are highly diverse and involved in competition between plasmids.

ABSTRACT: CRISPR-Cas systems provide prokaryotes with adaptive immune functions against viruses and other genetic parasites. In contrast to all other types of CRISPR-Cas systems, type IV has remained largely overlooked. Here, we describe a previously uncharted diversity of type IV gene cassettes, primarily encoded by plasmid-like elements from diverse prokaryotic taxa. Remarkably, via a comprehensive analysis of their CRISPR spacer content, these systems were found to exhibit a strong bias towards the targeting of other plasmids. Our data indicate that the functions of type IV systems have diverged from those of other host-related CRISPR-Cas immune systems to adopt a role in mediating conflicts between plasmids. Furthermore, we find evidence for cross-talk between certain type IV and type I CRISPR-C

SUBMITTER: Pinilla-Redondo R 

PROVIDER: S-EPMC7038947 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature