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Substrate Generation for Endonucleases of CRISPR/Cas Systems
Published on: September 8, 2012
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Virus-borne mini-CRISPR arrays are involved in interviral conflicts
Sofia Medvedeva1,2,3, Ying Liu1, Eugene V Koonin4
1Institut Pasteur, Department of Microbiology, 75015, Paris, France.
Nature Communications
|November 16, 2019
Summary
CRISPR-Cas immunity in archaea uses extensive spacer catalogs to target viruses. Some archaeal viruses possess mini-CRISPR arrays, driving virus evolution and speciation.
Area of Science:
- Microbiology
- Virology
- Genetics
Background:
- CRISPR-Cas systems provide adaptive immunity against viruses in prokaryotes.
- Targeting relies on matching viral protospacers to CRISPR array spacers.
- Sulfolobales archaea and their associated viruses are key models for studying these interactions.
Purpose of the Study:
- To comprehensively characterize the CRISPRome diversity in a natural Sulfolobales microbiome.
- To investigate the role of CRISPR targeting in viral genome evolution.
- To explore the function of virus-borne CRISPR arrays.
Main Methods:
- Deep sequencing of CRISPR arrays from environmental and cultured Sulfolobales samples.
- Bioinformatic analysis of CRISPR spacer diversity and dynamics.
- Comparative genomics of archaeal viruses and their CRISPR targeting strategies.
Main Results:
- Sequenced 25 million CRISPR spacers from a single site, revealing unprecedented diversity and temporal dynamics.
- Demonstrated that CRISPR targeting significantly drives the evolution of closely related virus strains.
- Identified archaeal viruses encoding functional mini-CRISPR arrays, capable of targeting other viruses.
Conclusions:
- CRISPR targeting is a major evolutionary force shaping archaeal virus populations.
- Virus-borne CRISPR arrays represent a novel mechanism for superinfection exclusion.
- These virus-encoded systems contribute to archaeal virus speciation and diversification.
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