CRISPR-Cas adaptation in Escherichia coli

Mitic, Damjan; Bolt, Edward L.; Ivancic-Bace, Ivana

Abstract

Prokaryotes use the adaptive immunity mediated via the Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR associated (CRISPR-Cas) system for protection against invading elements such as phages and plasmids. The immunity is achieved by capturing small DNA fragments or spacers from foreign nucleic acids (protospacers) and integrating them into the host CRISPR locus. This step of CRISPR-Cas immunity called ‘naïve CRISPR adaptation’ requires the conserved Cas1–Cas2 complex and is often supported by variable host proteins that assist in spacer processing and integration. Bacteria that have acquired new spacers become immune to the same invading elements when reinfected. CRISPR-Cas immunity can also be updated by integrating new spacers from the same invading elements, a process called ‘primed adaptation’. Only properly selected and integrated spacers are functional in the next steps of CRISPR immunity when their processed transcripts are used for RNA-guided target recognition and interference (target degradation). Capturing, trimming, and integrating new spacers in the correct orientation are universal steps of adaptation to all CRISPR-Cas systems, but some details are CRISPR-Cas type-specific and species-specific. In this review, we provide an overview of the mechanisms of CRISPR-Cas class 1 type I-E adaptation in Escherichia coli as a general model for adaptation processes (DNA capture and integration) that have been studied in detail. We focus on the role of host non-Cas proteins involved in adaptation, particularly on the role of homologous recombination.

Citation

Mitic, D., Bolt, E. L., & Ivancic-Bace, I. (2023). CRISPR-Cas adaptation in Escherichia coli. Bioscience Reports, 43(3), Article BSR20221198. https://doi.org/10.1042/BSR20221198

• Journal Article Type: Review
• Acceptance Date: Feb 21, 2023
• Online Publication Date: Mar 9, 2023
• Publication Date: Mar 1, 2023
• Deposit Date: Jun 30, 2023
• Publicly Available Date: Jun 30, 2023
• Journal: Bioscience Reports
• Print ISSN: 0144-8463
• Electronic ISSN: 1573-4935
• Publisher: Portland Press Ltd.
• Peer Reviewed: Peer Reviewed
• Volume: 43
• Issue: 3
• Article Number: BSR20221198
• DOI: https://doi.org/10.1042/BSR20221198
• Keywords: Cell Biology; Molecular Biology; Biochemistry; Biophysics
• Public URL: https://nottingham-repository.worktribe.com/output/18223182
• Publisher URL: https://portlandpress.com/bioscirep/article/43/3/BSR20221198/232582/CRISPR-Cas-adaptation-in-Escherichia-coli
• Additional Information: © 2023 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY).