RT Journal Article
SR Electronic
T1 CRISPR-Cas systems are widespread accessory elements across bacterial and archaeal plasmids
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.06.04.447074
DO 10.1101/2021.06.04.447074
A1 Rafael Pinilla-Redondo
A1 Jakob Russel
A1 David Mayo-Muñoz
A1 Shiraz A. Shah
A1 Roger A. Garrett
A1 Joseph Nesme
A1 Jonas S. Madsen
A1 Peter C. Fineran
A1 Søren J. Sørensen
YR 2021
UL http://biorxiv.org/content/early/2021/06/04/2021.06.04.447074.abstract
AB Many prokaryotes encode CRISPR-Cas systems as immune protection against mobile genetic elements (MGEs), yet, a number of MGEs also harbor CRISPR-Cas components. With a few exceptions, CRISPR-Cas loci encoded on MGEs are uncharted and a comprehensive analysis of their distribution, prevalence, diversity, and function is lacking. Here, we systematically investigated CRISPR-Cas loci across the largest curated collection of natural bacterial and archaeal plasmids. CRISPR-Cas loci are widely but heterogeneously distributed across plasmids and, in comparison to host chromosomes, their mean prevalence per Mbp is higher and their distribution is markedly distinct. Furthermore, the spacer content of plasmid CRISPRs exhibits a strong targeting bias towards other plasmids, while chromosomal arrays are enriched with virus-targeting spacers. These contrasting targeting preferences dominate across the diversity of CRISPR-Cas subtypes and host taxa, highlighting the genetic independence of plasmids and suggesting a major role of CRISPR-Cas for mediating plasmid-plasmid conflicts. Altogether, CRISPR-Cas are frequent accessory components of many plasmids, which is an overlooked phenomenon that possibly facilitates their dissemination across microbiomes.Competing Interest StatementThe authors have declared no competing interest.