51
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Vink JNA, Baijens JHL, Brouns SJJ. PAM-repeat associations and spacer selection preferences in single and co-occurring CRISPR-Cas systems. Genome Biol 2021; 22:281. [PMID: 34593010 PMCID: PMC8482600 DOI: 10.1186/s13059-021-02495-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/09/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The adaptive CRISPR-Cas immune system stores sequences from past invaders as spacers in CRISPR arrays and thereby provides direct evidence that links invaders to hosts. Mapping CRISPR spacers has revealed many aspects of CRISPR-Cas biology, including target requirements such as the protospacer adjacent motif (PAM). However, studies have so far been limited by a low number of mapped spacers in the database. RESULTS By using vast metagenomic sequence databases, we map approximately one-third of more than 200,000 unique CRISPR spacers from a variety of microbes and derive a catalog of more than two hundred unique PAM sequences associated with specific CRISPR-Cas subtypes. These PAMs are further used to correctly assign the orientation of CRISPR arrays, revealing conserved patterns between the last nucleotides of the CRISPR repeat and PAM. We could also deduce CRISPR-Cas subtype-specific preferences for targeting either template or coding strand of open reading frames. While some DNA-targeting systems (type I-E and type II systems) prefer the template strand and avoid mRNA, other DNA- and RNA-targeting systems (types I-A and I-B and type III systems) prefer the coding strand and mRNA. In addition, we find large-scale evidence that both CRISPR-Cas adaptation machinery and CRISPR arrays are shared between different CRISPR-Cas systems. This could lead to simultaneous DNA and RNA targeting of invaders, which may be effective at combating mobile genetic invaders. CONCLUSIONS This study has broad implications for our understanding of how CRISPR-Cas systems work in a wide range of organisms for which only the genome sequence is known.
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Affiliation(s)
- Jochem N A Vink
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Jan H L Baijens
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands.
- Kavli Institute of Nanoscience, Delft, The Netherlands.
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52
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Campa AR, Smith LM, Hampton HG, Sharma S, Jackson SA, Bischler T, Sharma CM, Fineran PC. The Rsm (Csr) post-transcriptional regulatory pathway coordinately controls multiple CRISPR-Cas immune systems. Nucleic Acids Res 2021; 49:9508-9525. [PMID: 34403463 PMCID: PMC8450108 DOI: 10.1093/nar/gkab704] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 12/15/2022] Open
Abstract
CRISPR-Cas systems provide bacteria with adaptive immunity against phages and plasmids; however, pathways regulating their activity are not well defined. We recently developed a high-throughput genome-wide method (SorTn-seq) and used this to uncover CRISPR-Cas regulators. Here, we demonstrate that the widespread Rsm/Csr pathway regulates the expression of multiple CRISPR-Cas systems in Serratia (type I-E, I-F and III-A). The main pathway component, RsmA (CsrA), is an RNA-binding post-transcriptional regulator of carbon utilisation, virulence and motility. RsmA binds cas mRNAs and suppresses type I and III CRISPR-Cas interference in addition to adaptation by type I systems. Coregulation of CRISPR-Cas and flagella by the Rsm pathway allows modulation of adaptive immunity when changes in receptor availability would alter susceptibility to flagella-tropic phages. Furthermore, we show that Rsm controls CRISPR-Cas in other genera, suggesting conservation of this regulatory strategy. Finally, we identify genes encoding RsmA homologues in phages, which have the potential to manipulate the physiology of host bacteria and might provide an anti-CRISPR activity.
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Affiliation(s)
- Aroa Rey Campa
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bio-Protection Research Centre, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Leah M Smith
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Hannah G Hampton
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Sahil Sharma
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Thorsten Bischler
- Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Cynthia M Sharma
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bio-Protection Research Centre, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Genetics Otago, University of Otago, Dunedin, New Zealand
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53
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Ma CH, Javanmardi K, Finkelstein IJ, Jayaram M. Disintegration promotes protospacer integration by the Cas1-Cas2 complex. eLife 2021; 10:65763. [PMID: 34435949 PMCID: PMC8390005 DOI: 10.7554/elife.65763] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 08/11/2021] [Indexed: 12/16/2022] Open
Abstract
‘Disintegration’—the reversal of transposon DNA integration at a target site—is regarded as an abortive off-pathway reaction. Here, we challenge this view with a biochemical investigation of the mechanism of protospacer insertion, which is mechanistically analogous to DNA transposition, by the Streptococcus pyogenes Cas1-Cas2 complex. In supercoiled target sites, the predominant outcome is the disintegration of one-ended insertions that fail to complete the second integration event. In linear target sites, one-ended insertions far outnumber complete protospacer insertions. The second insertion event is most often accompanied by the disintegration of the first, mediated either by the 3′-hydroxyl exposed during integration or by water. One-ended integration intermediates may mature into complete spacer insertions via DNA repair pathways that are also involved in transposon mobility. We propose that disintegration-promoted integration is functionally important in the adaptive phase of CRISPR-mediated bacterial immunity, and perhaps in other analogous transposition reactions.
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Affiliation(s)
- Chien-Hui Ma
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
| | - Kamyab Javanmardi
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, United States
| | - Makkuni Jayaram
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
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54
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Steens JA, Zhu Y, Taylor DW, Bravo JPK, Prinsen SHP, Schoen CD, Keijser BJF, Ossendrijver M, Hofstra LM, Brouns SJJ, Shinkai A, van der Oost J, Staals RHJ. SCOPE enables type III CRISPR-Cas diagnostics using flexible targeting and stringent CARF ribonuclease activation. Nat Commun 2021; 12:5033. [PMID: 34413302 PMCID: PMC8376896 DOI: 10.1038/s41467-021-25337-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 07/30/2021] [Indexed: 02/07/2023] Open
Abstract
Characteristic properties of type III CRISPR-Cas systems include recognition of target RNA and the subsequent induction of a multifaceted immune response. This involves sequence-specific cleavage of the target RNA and production of cyclic oligoadenylate (cOA) molecules. Here we report that an exposed seed region at the 3' end of the crRNA is essential for target RNA binding and cleavage, whereas cOA production requires base pairing at the 5' end of the crRNA. Moreover, we uncover that the variation in the size and composition of type III complexes within a single host results in variable seed regions. This may prevent escape by invading genetic elements, while controlling cOA production tightly to prevent unnecessary damage to the host. Lastly, we use these findings to develop a new diagnostic tool, SCOPE, for the specific detection of SARS-CoV-2 from human nasal swab samples, revealing sensitivities in the atto-molar range.
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Affiliation(s)
- Jurre A. Steens
- grid.4818.50000 0001 0791 5666Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands ,Scope Biosciences, Wageningen, The Netherlands
| | - Yifan Zhu
- grid.4818.50000 0001 0791 5666Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - David W. Taylor
- grid.89336.370000 0004 1936 9924Department of Molecular Biosciences, University of Texas at Austin, Austin, TX USA ,grid.89336.370000 0004 1936 9924Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX USA ,grid.89336.370000 0004 1936 9924Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX USA ,grid.89336.370000 0004 1936 9924LIVESTRONG Cancer Institutes, Dell Medical School, Austin, TX USA
| | - Jack P. K. Bravo
- grid.89336.370000 0004 1936 9924Department of Molecular Biosciences, University of Texas at Austin, Austin, TX USA
| | | | - Cor D. Schoen
- grid.4818.50000 0001 0791 5666BioInteractions and Plant Health, Wageningen Plant Research, Wageningen, The Netherlands
| | | | | | - L. Marije Hofstra
- grid.7692.a0000000090126352Virology, Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stan J. J. Brouns
- grid.5292.c0000 0001 2097 4740Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
| | - Akeo Shinkai
- grid.472717.0RIKEN SPring-8 Center, Sayo, Hyogo, Japan ,grid.7597.c0000000094465255Present Address: RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - John van der Oost
- grid.4818.50000 0001 0791 5666Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Raymond H. J. Staals
- grid.4818.50000 0001 0791 5666Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
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55
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Lin J, Shen Y, Ni J, She Q. A type III-A CRISPR-Cas system mediates co-transcriptional DNA cleavage at the transcriptional bubbles in close proximity to active effectors. Nucleic Acids Res 2021; 49:7628-7643. [PMID: 34197611 PMCID: PMC8287949 DOI: 10.1093/nar/gkab590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/18/2021] [Accepted: 06/24/2021] [Indexed: 12/26/2022] Open
Abstract
Many type III CRISPR–Cas systems rely on the cyclic oligoadenylate (cOA) signaling pathway to exert immunization. However, LdCsm, a type III-A lactobacilli immune system mediates efficient plasmid clearance in spite of lacking cOA signaling. Thus, the system provides a good model for detailed characterization of the RNA-activated DNase in vitro and in vivo. We found ATP functions as a ligand to enhance the LdCsm ssDNase, and the ATP enhancement is essential for in vivo plasmid clearance. In vitro assays demonstrated LdCsm cleaved transcriptional bubbles at any positions in non-template strand, suggesting that DNA cleavage may occur for transcribing DNA. Destiny of target plasmid versus nontarget plasmid in Escherichia coli cells was investigated, and this revealed that the LdCsm effectors mediated co-transcriptional DNA cleavage to both target and nontarget plasmids, suggesting LdCsm effectors can mediate DNA cleavage to any transcriptional bubbles in close proximity upon activation. Subcellular locations of active LdCsm effectors were then manipulated by differential expression of LdCsm and CTR, and the data supported the hypothesis. Strikingly, stepwise induction experiments indicated allowing diffusion of LdCsm effector led to massive chromosomal DNA degradation, suggesting this unique IIIA system can facilitate infection abortion to eliminate virus-infected cells.
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Affiliation(s)
- Jinzhong Lin
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Jimo, Qingdao, Shandong 266237, P.R. China.,Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Yulong Shen
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Jimo, Qingdao, Shandong 266237, P.R. China
| | - Jinfeng Ni
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Jimo, Qingdao, Shandong 266237, P.R. China
| | - Qunxin She
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Jimo, Qingdao, Shandong 266237, P.R. China.,Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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56
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Jia N, Patel DJ. Structure-based functional mechanisms and biotechnology applications of anti-CRISPR proteins. Nat Rev Mol Cell Biol 2021; 22:563-579. [PMID: 34089013 DOI: 10.1038/s41580-021-00371-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2021] [Indexed: 02/03/2023]
Abstract
CRISPR loci and Cas proteins provide adaptive immunity in prokaryotes against invading bacteriophages and plasmids. In response, bacteriophages have evolved a broad spectrum of anti-CRISPR proteins (anti-CRISPRs) to counteract and overcome this immunity pathway. Numerous anti-CRISPRs have been identified to date, which suppress single-subunit Cas effectors (in CRISPR class 2, type II, V and VI systems) and multisubunit Cascade effectors (in CRISPR class 1, type I and III systems). Crystallography and cryo-electron microscopy structural studies of anti-CRISPRs bound to effector complexes, complemented by functional experiments in vitro and in vivo, have identified four major CRISPR-Cas suppression mechanisms: inhibition of CRISPR-Cas complex assembly, blocking of target binding, prevention of target cleavage, and degradation of cyclic oligonucleotide signalling molecules. In this Review, we discuss novel mechanistic insights into anti-CRISPR function that have emerged from X-ray crystallography and cryo-electron microscopy studies, and how these structures in combination with function studies provide valuable tools for the ever-growing CRISPR-Cas biotechnology toolbox, to be used for precise and robust genome editing and other applications.
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Affiliation(s)
- Ning Jia
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA. .,Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China.
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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57
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Isaev AB, Musharova OS, Severinov KV. Microbial Arsenal of Antiviral Defenses. Part II. BIOCHEMISTRY (MOSCOW) 2021; 86:449-470. [PMID: 33941066 DOI: 10.1134/s0006297921040064] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Bacteriophages or phages are viruses that infect bacterial cells (for the scope of this review we will also consider viruses that infect Archaea). The constant threat of phage infection is a major force that shapes evolution of microbial genomes. To withstand infection, bacteria had evolved numerous strategies to avoid recognition by phages or to directly interfere with phage propagation inside the cell. Classical molecular biology and genetic engineering had been deeply intertwined with the study of phages and host defenses. Nowadays, owing to the rise of phage therapy, broad application of CRISPR-Cas technologies, and development of bioinformatics approaches that facilitate discovery of new systems, phage biology experiences a revival. This review describes variety of strategies employed by microbes to counter phage infection. In the first part defense associated with cell surface, roles of small molecules, and innate immunity systems relying on DNA modification were discussed. The second part focuses on adaptive immunity systems, abortive infection mechanisms, defenses associated with mobile genetic elements, and novel systems discovered in recent years through metagenomic mining.
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Affiliation(s)
- Artem B Isaev
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 143028, Russia.
| | - Olga S Musharova
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 143028, Russia. .,Institute of Molecular Genetics, Moscow, 119334, Russia
| | - Konstantin V Severinov
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, 143028, Russia. .,Waksman Institute of Microbiology, Piscataway, NJ 08854, USA
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58
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Osakabe K, Wada N, Murakami E, Miyashita N, Osakabe Y. Genome editing in mammalian cells using the CRISPR type I-D nuclease. Nucleic Acids Res 2021; 49:6347-6363. [PMID: 34076237 PMCID: PMC8216271 DOI: 10.1093/nar/gkab348] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 04/15/2021] [Accepted: 05/20/2021] [Indexed: 12/26/2022] Open
Abstract
Adoption of CRISPR-Cas systems, such as CRISPR-Cas9 and CRISPR-Cas12a, has revolutionized genome engineering in recent years; however, application of genome editing with CRISPR type I-the most abundant CRISPR system in bacteria-remains less developed. Type I systems, such as type I-E, and I-F, comprise the CRISPR-associated complex for antiviral defense ('Cascade': Cas5, Cas6, Cas7, Cas8 and the small subunit) and Cas3, which degrades the target DNA; in contrast, for the sub-type CRISPR-Cas type I-D, which lacks a typical Cas3 nuclease in its CRISPR locus, the mechanism of target DNA degradation remains unknown. Here, we found that Cas10d is a functional nuclease in the type I-D system, performing the role played by Cas3 in other CRISPR-Cas type I systems. The type I-D system can be used for targeted mutagenesis of genomic DNA in human cells, directing both bi-directional long-range deletions and short insertions/deletions. Our findings suggest the CRISPR-Cas type I-D system as a unique effector pathway in CRISPR that can be repurposed for genome engineering in eukaryotic cells.
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Affiliation(s)
- Keishi Osakabe
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Naoki Wada
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Emi Murakami
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Naoyuki Miyashita
- Department of Computational Systems Biology, Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Wakayama 649-6493, Japan
| | - Yuriko Osakabe
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502, Japan
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59
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Santiago-Frangos A, Hall LN, Nemudraia A, Nemudryi A, Krishna P, Wiegand T, Wilkinson RA, Snyder DT, Hedges JF, Cicha C, Lee HH, Graham A, Jutila MA, Taylor MP, Wiedenheft B. Intrinsic signal amplification by type III CRISPR-Cas systems provides a sequence-specific SARS-CoV-2 diagnostic. Cell Rep Med 2021; 2:100319. [PMID: 34075364 PMCID: PMC8157118 DOI: 10.1016/j.xcrm.2021.100319] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 12/23/2022]
Abstract
There is an urgent need for inexpensive new technologies that enable fast, reliable, and scalable detection of viruses. Here, we repurpose the type III CRISPR-Cas system for sensitive and sequence-specific detection of SARS-CoV-2. RNA recognition by the type III CRISPR complex triggers Cas10-mediated polymerase activity, which simultaneously generates pyrophosphates, protons, and cyclic oligonucleotides. We show that all three Cas10-polymerase products are detectable using colorimetric or fluorometric readouts. We design ten guide RNAs that target conserved regions of SARS-CoV-2 genomes. Multiplexing improves the sensitivity of amplification-free RNA detection from 107 copies/μL for a single guide RNA to 106 copies/μL for ten guides. To decrease the limit of detection to levels that are clinically relevant, we developed a two-pot reaction consisting of RT-LAMP followed by T7-transcription and type III CRISPR-based detection. The two-pot reaction has a sensitivity of 200 copies/μL and is completed using patient samples in less than 30 min.
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Affiliation(s)
| | - Laina N. Hall
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Anna Nemudraia
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Artem Nemudryi
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Pushya Krishna
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Tanner Wiegand
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Royce A. Wilkinson
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Deann T. Snyder
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Jodi F. Hedges
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Calvin Cicha
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Helen H. Lee
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Ava Graham
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Mark A. Jutila
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Matthew P. Taylor
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
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60
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Taylor HN, Laderman E, Armbrust M, Hallmark T, Keiser D, Bondy-Denomy J, Jackson RN. Positioning Diverse Type IV Structures and Functions Within Class 1 CRISPR-Cas Systems. Front Microbiol 2021; 12:671522. [PMID: 34093491 PMCID: PMC8175902 DOI: 10.3389/fmicb.2021.671522] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/26/2021] [Indexed: 12/26/2022] Open
Abstract
Type IV CRISPR systems encode CRISPR associated (Cas)-like proteins that combine with small RNAs to form multi-subunit ribonucleoprotein complexes. However, the lack of Cas nucleases, integrases, and other genetic features commonly observed in most CRISPR systems has made it difficult to predict type IV mechanisms of action and biological function. Here we summarize recent bioinformatic and experimental advancements that collectively provide the first glimpses into the function of specific type IV subtypes. We also provide a bioinformatic and structural analysis of type IV-specific proteins within the context of multi-subunit (class 1) CRISPR systems, informing future studies aimed at elucidating the function of these cryptic systems.
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Affiliation(s)
- Hannah N. Taylor
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Eric Laderman
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, United States
| | - Matt Armbrust
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Thomson Hallmark
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Dylan Keiser
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, United States
| | - Ryan N. Jackson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
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61
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Athukoralage JS, White MF. Cyclic oligoadenylate signalling and regulation by ring nucleases during type III CRISPR defence. RNA (NEW YORK, N.Y.) 2021; 27:rna.078739.121. [PMID: 33986148 PMCID: PMC8284326 DOI: 10.1261/rna.078739.121] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/08/2021] [Indexed: 06/12/2023]
Abstract
In prokaryotes, CRISPR-Cas immune systems recognise and cleave foreign nucleic acids to defend against Mobile Genetic Elements (MGEs). Type III CRISPR-Cas complexes also synthesise cyclic oligoadenylate (cOA) second messengers, which activate CRISPR ancillary proteins involved in antiviral defence. In particular, cOA-stimulated nucleases degrade RNA and DNA non-specifically, which slows MGE replication but also impedes cell growth, necessitating mechanisms to eliminate cOA in order to mitigate collateral damage. Extant cOA is degraded by a new class of enzyme termed a 'ring nuclease', which cleaves cOA specifically and switches off CRISPR ancillary enzymes. Several ring nuclease families have been characterised to date, including a family used by MGEs to circumvent CRISPR immunity, and encompass diverse protein folds and distinct cOA cleavage mechanisms. In this review we outline cOA signalling, discuss how different ring nucleases regulate the cOA signalling pathway, and reflect on parallels between cyclic nucleotide-based immune systems to reveal new areas for exploration.
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62
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Zhao R, Yang Y, Zheng F, Zeng Z, Feng W, Jin X, Wang J, Yang K, Liang YX, She Q, Han W. A Membrane-Associated DHH-DHHA1 Nuclease Degrades Type III CRISPR Second Messenger. Cell Rep 2021; 32:108133. [PMID: 32937129 DOI: 10.1016/j.celrep.2020.108133] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/21/2020] [Accepted: 08/20/2020] [Indexed: 12/26/2022] Open
Abstract
Type III CRISPR-Cas systems initiate an intracellular signaling pathway to confer immunity. The signaling pathway includes synthesis of cyclic oligo-adenylate (cOA) and activation of the RNase activity of type III accessory ribonuclease Csm6/Csx1 by cOA. After the immune response, cOA should be cleared on time to avoid constant cellular RNA degradation. In this study, we find a metal-dependent cOA degradation activity in Sulfolobus islandicus. The activity is associated with the cell membrane and able to accelerate cOA clearance at a high cOA level. Further, we show that a metal-dependent and membrane-associated DHH-DHHA1 family nuclease (MAD) rapidly cleaves cOA and deactivates Csx1 ribonuclease. The cOA degradation efficiency of MAD is much higher than the cellular ring nuclease. However, the subcellular organization may prevent it from degrading nascent cOA. Together, the data suggest that MAD acts as the second cOA degrader after the ring nuclease to remove diffused redundant cOA.
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Affiliation(s)
- Ruiliang Zhao
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yang Yang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Fan Zheng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Zhifeng Zeng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Wenqian Feng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Xuexia Jin
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Jiayi Wang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ke Yang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yun Xiang Liang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Qunxin She
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, 266237 Qingdao, China; Danish Archaea Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, 2200 Copenhagen N, Denmark
| | - Wenyuan Han
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China.
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63
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Abstract
CRISPR-Cas systems provide bacteria and archaea with adaptive, heritable immunity against their viruses (bacteriophages and phages) and other parasitic genetic elements. CRISPR-Cas systems are highly diverse, and we are only beginning to understand their relative importance in phage defense. In this review, we will discuss when and why CRISPR-Cas immunity against phages evolves, and how this, in turn, selects for the evolution of immune evasion by phages. Finally, we will discuss our current understanding of if, and when, we observe coevolution between CRISPR-Cas systems and phages, and how this may be influenced by the mechanism of CRISPR-Cas immunity.
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64
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Medina-Aparicio L, Rodriguez-Gutierrez S, Rebollar-Flores JE, Martínez-Batallar ÁG, Mendoza-Mejía BD, Aguirre-Partida ED, Vázquez A, Encarnación S, Calva E, Hernández-Lucas I. The CRISPR-Cas System Is Involved in OmpR Genetic Regulation for Outer Membrane Protein Synthesis in Salmonella Typhi. Front Microbiol 2021; 12:657404. [PMID: 33854491 PMCID: PMC8039139 DOI: 10.3389/fmicb.2021.657404] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/10/2021] [Indexed: 12/11/2022] Open
Abstract
The CRISPR-Cas cluster is found in many prokaryotic genomes including those of the Enterobacteriaceae family. Salmonella enterica serovar Typhi (S. Typhi) harbors a Type I-E CRISPR-Cas locus composed of cas3, cse1, cse2, cas7, cas5, cas6e, cas1, cas2, and a CRISPR1 array. In this work, it was determined that, in the absence of cas5 or cas2, the amount of the OmpC porin decreased substantially, whereas in individual cse2, cas6e, cas1, or cas3 null mutants, the OmpF porin was not observed in an electrophoretic profile of outer membrane proteins. Furthermore, the LysR-type transcriptional regulator LeuO was unable to positively regulate the expression of the quiescent OmpS2 porin, in individual S. Typhi cse2, cas5, cas6e, cas1, cas2, and cas3 mutants. Remarkably, the expression of the master porin regulator OmpR was dependent on the Cse2, Cas5, Cas6e, Cas1, Cas2, and Cas3 proteins. Therefore, the data suggest that the CRISPR-Cas system acts hierarchically on OmpR to control the synthesis of outer membrane proteins in S. Typhi.
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Affiliation(s)
- Liliana Medina-Aparicio
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sarahí Rodriguez-Gutierrez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Javier E Rebollar-Flores
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | | | - Blanca D Mendoza-Mejía
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Eira D Aguirre-Partida
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Alejandra Vázquez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sergio Encarnación
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Edmundo Calva
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Ismael Hernández-Lucas
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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65
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Zhu W, McQuarrie S, Grüschow S, McMahon SA, Graham S, Gloster TM, White MF. The CRISPR ancillary effector Can2 is a dual-specificity nuclease potentiating type III CRISPR defence. Nucleic Acids Res 2021; 49:2777-2789. [PMID: 33590098 PMCID: PMC7969007 DOI: 10.1093/nar/gkab073] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
Cells and organisms have a wide range of mechanisms to defend against infection by viruses and other mobile genetic elements (MGE). Type III CRISPR systems detect foreign RNA and typically generate cyclic oligoadenylate (cOA) second messengers that bind to ancillary proteins with CARF (CRISPR associated Rossman fold) domains. This results in the activation of fused effector domains for antiviral defence. The best characterised CARF family effectors are the Csm6/Csx1 ribonucleases and DNA nickase Can1. Here we investigate a widely distributed CARF family effector with a nuclease domain, which we name Can2 (CRISPR ancillary nuclease 2). Can2 is activated by cyclic tetra-adenylate (cA4) and displays both DNase and RNase activity, providing effective immunity against plasmid transformation and bacteriophage infection in Escherichia coli. The structure of Can2 in complex with cA4 suggests a mechanism for the cA4-mediated activation of the enzyme, whereby an active site cleft is exposed on binding the activator. These findings extend our understanding of type III CRISPR cOA signalling and effector function.
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Affiliation(s)
- Wenlong Zhu
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Stuart McQuarrie
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Stephen A McMahon
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Shirley Graham
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
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66
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Wang B, Zhang T, Yin J, Yu Y, Xu W, Ding J, Patel DJ, Yang H. Structural basis for self-cleavage prevention by tag:anti-tag pairing complementarity in type VI Cas13 CRISPR systems. Mol Cell 2021; 81:1100-1115.e5. [PMID: 33472057 PMCID: PMC8274241 DOI: 10.1016/j.molcel.2020.12.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/26/2020] [Accepted: 12/18/2020] [Indexed: 12/21/2022]
Abstract
Bacteria and archaea apply CRISPR-Cas surveillance complexes to defend against foreign invaders. These invading genetic elements are captured and integrated into the CRISPR array as spacer elements, guiding sequence-specific DNA/RNA targeting and cleavage. Recently, in vivo studies have shown that target RNAs with extended complementarity with repeat sequences flanking the target element (tag:anti-tag pairing) can dramatically reduce RNA cleavage by the type VI-A Cas13a system. Here, we report the cryo-EM structure of Leptotrichia shahii LshCas13acrRNA in complex with target RNA harboring tag:anti-tag pairing complementarity, with the observed conformational changes providing a molecular explanation for inactivation of the composite HEPN domain cleavage activity. These structural insights, together with in vitro biochemical and in vivo cell-based assays on key mutants, define the molecular principles underlying Cas13a's capacity to target and discriminate between self and non-self RNA targets. Our studies illuminate approaches to regulate Cas13a's cleavage activity, thereby influencing Cas13a-mediated biotechnological applications.
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Affiliation(s)
- Beibei Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Tianlong Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jun Yin
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - You Yu
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Wenhao Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Hui Yang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
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67
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Huang F, Zhu B. The Cyclic Oligoadenylate Signaling Pathway of Type III CRISPR-Cas Systems. Front Microbiol 2021; 11:602789. [PMID: 33552016 PMCID: PMC7854544 DOI: 10.3389/fmicb.2020.602789] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/11/2020] [Indexed: 12/24/2022] Open
Abstract
Type III CRISPR-Cas systems, which are widespread in both bacteria and archaea, provide immunity against DNA viruses and plasmids in a transcription-dependent manner. Since an unprecedented cyclic oligoadenylate (cOA) signaling pathway was discovered in type III systems in 2017, the cOA signaling has been extensively studied in recent 3 years, which has expanded our understanding of type III systems immune defense and also its counteraction by viruses. In this review, we summarized recent advances in cOA synthesis, cOA-activated effector protein, cOA signaling-mediated immunoprotection, and cOA signaling inhibition, and highlighted the crosstalk between cOA signaling and other cyclic oligonucleotide-mediated immunity discovered very recently.
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Affiliation(s)
- Fengtao Huang
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology and Shenzhen College, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Zhu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology and Shenzhen College, Huazhong University of Science and Technology, Wuhan, China
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68
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Collias D, Beisel CL. CRISPR technologies and the search for the PAM-free nuclease. Nat Commun 2021; 12:555. [PMID: 33483498 PMCID: PMC7822910 DOI: 10.1038/s41467-020-20633-y] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/03/2020] [Indexed: 12/20/2022] Open
Abstract
The ever-expanding set of CRISPR technologies and their programmable RNA-guided nucleases exhibit remarkable flexibility in DNA targeting. However, this flexibility comes with an ever-present constraint: the requirement for a protospacer adjacent motif (PAM) flanking each target. While PAMs play an essential role in self/nonself discrimination by CRISPR-Cas immune systems, this constraint has launched a far-reaching expedition for nucleases with relaxed PAM requirements. Here, we review ongoing efforts toward realizing PAM-free nucleases through natural ortholog mining and protein engineering. We also address potential consequences of fully eliminating PAM recognition and instead propose an alternative nuclease repertoire covering all possible PAM sequences.
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Affiliation(s)
- Daphne Collias
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA
| | - Chase L Beisel
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695-7905, USA.
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz Centre for Infection Research (HZI), 97080, Würzburg, Germany.
- Medical Faculty, University of Würzburg, 97080, Würzburg, Germany.
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69
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Smith LM, Jackson SA, Malone LM, Ussher JE, Gardner PP, Fineran PC. The Rcs stress response inversely controls surface and CRISPR-Cas adaptive immunity to discriminate plasmids and phages. Nat Microbiol 2021; 6:162-172. [PMID: 33398095 DOI: 10.1038/s41564-020-00822-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/23/2020] [Indexed: 12/16/2022]
Abstract
Bacteria harbour multiple innate defences and adaptive CRISPR-Cas systems that provide immunity against bacteriophages and mobile genetic elements. Although some bacteria modulate defences in response to population density, stress and metabolic state, a lack of high-throughput methods to systematically reveal regulators has hampered efforts to understand when and how immune strategies are deployed. We developed a robust approach called SorTn-seq, which combines saturation transposon mutagenesis, fluorescence-activated cell sorting and deep sequencing to characterize regulatory networks controlling CRISPR-Cas immunity in Serratia sp. ATCC 39006. We applied our technology to assess csm gene expression for ~300,000 mutants and uncovered multiple pathways regulating type III-A CRISPR-Cas expression. Mutation of igaA or mdoG activated the Rcs outer-membrane stress response, eliciting cell-surface-based innate immunity against diverse phages via the transcriptional regulators RcsB and RcsA. Activation of this Rcs phosphorelay concomitantly attenuated adaptive immunity by three distinct type I and III CRISPR-Cas systems. Rcs-mediated repression of CRISPR-Cas defence enabled increased acquisition and retention of plasmids. Dual downregulation of cell-surface receptors and adaptive immunity in response to stress by the Rcs pathway enables protection from phage infection without preventing the uptake of plasmids that may harbour beneficial traits.
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Affiliation(s)
- Leah M Smith
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Lucia M Malone
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - James E Ussher
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Paul P Gardner
- Genetics Otago, University of Otago, Dunedin, New Zealand.,Department of Biochemistry, University of Otago, Dunedin, New Zealand.,Bio-Protection Research Centre, University of Otago, Dunedin, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand. .,Genetics Otago, University of Otago, Dunedin, New Zealand. .,Bio-Protection Research Centre, University of Otago, Dunedin, New Zealand.
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70
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Shivram H, Cress BF, Knott GJ, Doudna JA. Controlling and enhancing CRISPR systems. Nat Chem Biol 2021; 17:10-19. [PMID: 33328654 PMCID: PMC8101458 DOI: 10.1038/s41589-020-00700-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/22/2020] [Indexed: 12/17/2022]
Abstract
Many bacterial and archaeal organisms use clustered regularly interspaced short palindromic repeats-CRISPR associated (CRISPR-Cas) systems to defend themselves from mobile genetic elements. These CRISPR-Cas systems are classified into six types based on their composition and mechanism. CRISPR-Cas enzymes are widely used for genome editing and offer immense therapeutic opportunity to treat genetic diseases. To realize their full potential, it is important to control the timing, duration, efficiency and specificity of CRISPR-Cas enzyme activities. In this Review we discuss the mechanisms of natural CRISPR-Cas regulatory biomolecules and engineering strategies that enhance or inhibit CRISPR-Cas immunity by altering enzyme function. We also discuss the potential applications of these CRISPR regulators and highlight unanswered questions about their evolution and purpose in nature.
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Affiliation(s)
- Haridha Shivram
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Brady F Cress
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Gavin J Knott
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
- Monash Biomedicine Discovery Institute, Department of Biochemistry & Molecular Biology, Monash University, Victoria, Australia
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA.
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, Berkeley, CA, USA.
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA, USA.
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71
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Mckay A, Burgio G. Harnessing CRISPR-Cas system diversity for gene editing technologies. J Biomed Res 2021; 35:91-106. [PMID: 33797415 PMCID: PMC8038530 DOI: 10.7555/jbr.35.20200184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The discovery and utilization of RNA-guided surveillance complexes, such as CRISPR-Cas9, for sequence-specific DNA or RNA cleavage, has revolutionised the process of gene modification or knockdown. To optimise the use of this technology, an exploratory race has ensued to discover or develop new RNA-guided endonucleases with the most flexible sequence targeting requirements, coupled with high cleavage efficacy and specificity. Here we review the constraints of existing gene editing and assess the merits of exploiting the diversity of CRISPR-Cas effectors as a methodology for surmounting these limitations.
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Affiliation(s)
- Alexander Mckay
- Department of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Gaetan Burgio
- Department of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
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72
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Molina R, Sofos N, Montoya G. Structural basis of CRISPR-Cas Type III prokaryotic defence systems. Curr Opin Struct Biol 2020; 65:119-129. [DOI: 10.1016/j.sbi.2020.06.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/06/2020] [Accepted: 06/16/2020] [Indexed: 12/26/2022]
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73
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74
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Artamonova D, Karneyeva K, Medvedeva S, Klimuk E, Kolesnik M, Yasinskaya A, Samolygo A, Severinov K. Spacer acquisition by Type III CRISPR-Cas system during bacteriophage infection of Thermus thermophilus. Nucleic Acids Res 2020; 48:9787-9803. [PMID: 32821943 PMCID: PMC7515739 DOI: 10.1093/nar/gkaa685] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/01/2020] [Accepted: 08/05/2020] [Indexed: 12/21/2022] Open
Abstract
Type III CRISPR–Cas systems provide immunity to foreign DNA by targeting its transcripts. Target recognition activates RNases and DNases that may either destroy foreign DNA directly or elicit collateral damage inducing death of infected cells. While some Type III systems encode a reverse transcriptase to acquire spacers from foreign transcripts, most contain conventional spacer acquisition machinery found in DNA-targeting systems. We studied Type III spacer acquisition in phage-infected Thermus thermophilus, a bacterium that lacks either a standalone reverse transcriptase or its fusion to spacer integrase Cas1. Cells with spacers targeting a subset of phage transcripts survived the infection, indicating that Type III immunity does not operate through altruistic suicide. In the absence of selection spacers were acquired from both strands of phage DNA, indicating that no mechanism ensuring acquisition of RNA-targeting spacers exists. Spacers that protect the host from the phage demonstrate a very strong strand bias due to positive selection during infection. Phages that escaped Type III interference accumulated deletions of integral number of codons in an essential gene and much longer deletions in a non-essential gene. This and the fact that Type III immunity can be provided by plasmid-borne mini-arrays open ways for genomic manipulation of Thermus phages.
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Affiliation(s)
- Daria Artamonova
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Karyna Karneyeva
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Sofia Medvedeva
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Evgeny Klimuk
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia.,Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Matvey Kolesnik
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Anna Yasinskaya
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Aleksei Samolygo
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Konstantin Severinov
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow 121205, Russia.,Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia.,Waksman Institute, Rutgers, The State University of New Jersey, NJ 08854 USA
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75
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Zink IA, Wimmer E, Schleper C. Heavily Armed Ancestors: CRISPR Immunity and Applications in Archaea with a Comparative Analysis of CRISPR Types in Sulfolobales. Biomolecules 2020; 10:E1523. [PMID: 33172134 PMCID: PMC7694759 DOI: 10.3390/biom10111523] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Prokaryotes are constantly coping with attacks by viruses in their natural environments and therefore have evolved an impressive array of defense systems. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is an adaptive immune system found in the majority of archaea and about half of bacteria which stores pieces of infecting viral DNA as spacers in genomic CRISPR arrays to reuse them for specific virus destruction upon a second wave of infection. In detail, small CRISPR RNAs (crRNAs) are transcribed from CRISPR arrays and incorporated into type-specific CRISPR effector complexes which further degrade foreign nucleic acids complementary to the crRNA. This review gives an overview of CRISPR immunity to newcomers in the field and an update on CRISPR literature in archaea by comparing the functional mechanisms and abundances of the diverse CRISPR types. A bigger fraction is dedicated to the versatile and prevalent CRISPR type III systems, as tremendous progress has been made recently using archaeal models in discerning the controlled molecular mechanisms of their unique tripartite mode of action including RNA interference, DNA interference and the unique cyclic-oligoadenylate signaling that induces promiscuous RNA shredding by CARF-domain ribonucleases. The second half of the review spotlights CRISPR in archaea outlining seminal in vivo and in vitro studies in model organisms of the euryarchaeal and crenarchaeal phyla, including the application of CRISPR-Cas for genome editing and gene silencing. In the last section, a special focus is laid on members of the crenarchaeal hyperthermophilic order Sulfolobales by presenting a thorough comparative analysis about the distribution and abundance of CRISPR-Cas systems, including arrays and spacers as well as CRISPR-accessory proteins in all 53 genomes available to date. Interestingly, we find that CRISPR type III and the DNA-degrading CRISPR type I complexes co-exist in more than two thirds of these genomes. Furthermore, we identified ring nuclease candidates in all but two genomes and found that they generally co-exist with the above-mentioned CARF domain ribonucleases Csx1/Csm6. These observations, together with published literature allowed us to draft a working model of how CRISPR-Cas systems and accessory proteins cross talk to establish native CRISPR anti-virus immunity in a Sulfolobales cell.
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76
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CRISPR-Cas adaptive immune systems in Sulfolobales: genetic studies and molecular mechanisms. SCIENCE CHINA-LIFE SCIENCES 2020; 64:678-696. [DOI: 10.1007/s11427-020-1745-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 05/25/2020] [Indexed: 12/26/2022]
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77
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Smalakyte D, Kazlauskiene M, F Havelund J, Rukšėnaitė A, Rimaite A, Tamulaitiene G, Færgeman NJ, Tamulaitis G, Siksnys V. Type III-A CRISPR-associated protein Csm6 degrades cyclic hexa-adenylate activator using both CARF and HEPN domains. Nucleic Acids Res 2020; 48:9204-9217. [PMID: 32766806 PMCID: PMC7498309 DOI: 10.1093/nar/gkaa634] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/12/2020] [Accepted: 08/06/2020] [Indexed: 12/26/2022] Open
Abstract
The type III CRISPR–Cas systems provide immunity against invading nucleic acids through the coordinated transcription-dependent DNA targeting and cyclic adenylate (cAn)-activated RNA degradation. Here, we show that both these pathways contribute to the Streptococcus thermophilus (St) type III-A CRISPR–Cas immunity. HPLC-MS analysis revealed that in the heterologous Escherichia coli host the StCsm effector complex predominantly produces cA5 and cA6. cA6 acts as a signaling molecule that binds to the CARF domain of StCsm6 to activate non-specific RNA degradation by the HEPN domain. By dissecting StCsm6 domains we demonstrate that both CARF and HEPN domains act as ring nucleases that degrade cAns to switch signaling off. CARF ring nuclease converts cA6 to linear A6>p and to the final A3>p product. HEPN domain, which typically degrades RNA, also shows ring nuclease activity and indiscriminately degrades cA6 or other cAns down to A>p. We propose that concerted action of both ring nucleases enables self-regulation of the RNase activity in the HEPN domain and eliminates all cAn secondary messengers in the cell when viral infection is combated by a coordinated action of Csm effector and the cA6-activated Csm6 ribonuclease.
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Affiliation(s)
- Dalia Smalakyte
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Migle Kazlauskiene
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Jesper F Havelund
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Audronė Rukšėnaitė
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Auguste Rimaite
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Giedre Tamulaitiene
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Nils J Færgeman
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, Denmark
| | - Gintautas Tamulaitis
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
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78
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Liu TY, Doudna JA. Chemistry of Class 1 CRISPR-Cas effectors: Binding, editing, and regulation. J Biol Chem 2020; 295:14473-14487. [PMID: 32817336 PMCID: PMC7573268 DOI: 10.1074/jbc.rev120.007034] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/13/2020] [Indexed: 12/19/2022] Open
Abstract
Among the multiple antiviral defense mechanisms found in prokaryotes, CRISPR-Cas systems stand out as the only known RNA-programmed pathways for detecting and destroying bacteriophages and plasmids. Class 1 CRISPR-Cas systems, the most widespread and diverse of these adaptive immune systems, use an RNA-guided multiprotein complex to find foreign nucleic acids and trigger their destruction. In this review, we describe how these multisubunit complexes target and cleave DNA and RNA and how regulatory molecules control their activities. We also highlight similarities to and differences from Class 2 CRISPR-Cas systems, which use a single-protein effector, as well as other types of bacterial and eukaryotic immune systems. We summarize current applications of the Class 1 CRISPR-Cas systems for DNA/RNA modification, control of gene expression, and nucleic acid detection.
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Affiliation(s)
- Tina Y Liu
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Department of Chemistry, University of California, Berkeley, California, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California, USA
- Innovative Genomics Institute, University of California, Berkeley, California, USA
- Howard Hughes Medical Institute, University of California, Berkeley, California, USA
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- Gladstone Institutes, University of California, San Francisco, California, USA
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79
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Samolygo A, Athukoralage JS, Graham S, White MF. Fuse to defuse: a self-limiting ribonuclease-ring nuclease fusion for type III CRISPR defence. Nucleic Acids Res 2020; 48:6149-6156. [PMID: 32347937 PMCID: PMC7293037 DOI: 10.1093/nar/gkaa298] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/13/2020] [Accepted: 04/17/2020] [Indexed: 12/20/2022] Open
Abstract
Type III CRISPR systems synthesise cyclic oligoadenylate (cOA) second messengers in response to viral infection of bacteria and archaea, potentiating an immune response by binding and activating ancillary effector nucleases such as Csx1. As these effectors are not specific for invading nucleic acids, a prolonged activation can result in cell dormancy or death. Some archaeal species encode a specialised ring nuclease enzyme (Crn1) to degrade cyclic tetra-adenylate (cA4) and deactivate the ancillary nucleases. Some archaeal viruses and bacteriophage encode a potent ring nuclease anti-CRISPR, AcrIII-1, to rapidly degrade cA4 and neutralise immunity. Homologues of this enzyme (named Crn2) exist in type III CRISPR systems but are uncharacterised. Here we describe an unusual fusion between cA4-activated CRISPR ribonuclease (Csx1) and a cA4-degrading ring nuclease (Crn2) from Marinitoga piezophila. The protein has two binding sites that compete for the cA4 ligand, a canonical cA4-activated ribonuclease activity in the Csx1 domain and a potent cA4 ring nuclease activity in the C-terminal Crn2 domain. The cA4 binding affinities and activities of the two constituent enzymes in the fusion protein may have evolved to ensure a robust but time-limited cOA-activated ribonuclease activity that is finely tuned to cA4 levels as a second messenger of infection.
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Affiliation(s)
- Aleksei Samolygo
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard, 30/1, Moscow 121205, Russian Federation.,Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Januka S Athukoralage
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Shirley Graham
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
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80
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Garrett S, Shiimori M, Watts EA, Clark L, Graveley BR, Terns MP. Primed CRISPR DNA uptake in Pyrococcus furiosus. Nucleic Acids Res 2020; 48:6120-6135. [PMID: 32421777 PMCID: PMC7293040 DOI: 10.1093/nar/gkaa381] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 04/15/2020] [Accepted: 05/11/2020] [Indexed: 12/19/2022] Open
Abstract
CRISPR-Cas adaptive immune systems are used by prokaryotes to defend against invaders like viruses and other mobile genetic elements. Immune memories are stored in the form of 'spacers' which are short DNA sequences that are captured from invaders and added to the CRISPR array during a process called 'adaptation'. Spacers are transcribed and the resulting CRISPR (cr)RNAs assemble with different Cas proteins to form effector complexes that recognize matching nucleic acid and destroy it ('interference'). Adaptation can be 'naïve', i.e. independent of any existing spacer matches, or it can be 'primed', i.e. spurred by the crRNA-mediated detection of a complete or partial match to an invader sequence. Here we show that primed adaptation occurs in Pyrococcus furiosus. Although P. furiosus has three distinct CRISPR-Cas interference systems (I-B, I-A and III-B), only the I-B system and Cas3 were necessary for priming. Cas4, which is important for selection and processing of new spacers in naïve adaptation, was also essential for priming. Loss of either the I-B effector proteins or Cas3 reduced naïve adaptation. However, when Cas3 and all crRNP genes were deleted, uptake of correctly processed spacers was observed, indicating that none of these interference proteins are necessary for naïve adaptation.
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Affiliation(s)
- Sandra Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Masami Shiimori
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Elizabeth A Watts
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Landon Clark
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Michael P Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.,Department of Microbiology, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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81
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Newire E, Aydin A, Juma S, Enne VI, Roberts AP. Identification of a Type IV-A CRISPR-Cas System Located Exclusively on IncHI1B/IncFIB Plasmids in Enterobacteriaceae. Front Microbiol 2020; 11:1937. [PMID: 32903441 PMCID: PMC7434947 DOI: 10.3389/fmicb.2020.01937] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/22/2020] [Indexed: 12/15/2022] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) are diverse immune systems found in many prokaryotic genomes that target invading foreign DNA such as bacteriophages and plasmids. There are multiple types of CRISPR with arguably the most enigmatic being Type IV. During an investigation of CRISPR carriage in clinical, multi-drug resistant, Klebsiella pneumoniae, a Type IV-A3 CRISPR-Cas system was detected on plasmids from two K. pneumoniae isolates from Egypt (isolated in 2002-2003) and a single K. pneumoniae isolate from the United Kingdom (isolated in 2017). Sequence analysis of all other genomes available in GenBank revealed that this CRISPR-Cas system was present on 28 other plasmids from various Enterobacteriaceae hosts and was never found on a bacterial chromosome. This system is exclusively located on IncHI1B/IncFIB plasmids and is associated with multiple putative transposable elements. Expression of the cas loci was confirmed in the available clinical isolates by RT-PCR. In all cases, the CRISPR-Cas system has a single CRISPR array (CRISPR1) upstream of the cas loci which has several, conserved, spacers which, amongst things, match regions within conjugal transfer genes of IncFIIK/IncFIB(K) plasmids. Our results reveal a Type IV-A3 CRISPR-Cas system exclusively located on IncHI1B/IncFIB plasmids in Enterobacteriaceae that is likely to be able to target IncFIIK/IncFIB(K) plasmids presumably facilitating intracellular, inter-plasmid competition.
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Affiliation(s)
- Enas Newire
- UCL Eastman Dental Institute, University College London, London, United Kingdom
| | - Alp Aydin
- Centre for Clinical Microbiology, Royal Free Hospital, University College London, London, United Kingdom
| | - Samina Juma
- Centre for Clinical Microbiology, Royal Free Hospital, University College London, London, United Kingdom
| | - Virve I. Enne
- Centre for Clinical Microbiology, Royal Free Hospital, University College London, London, United Kingdom
| | - Adam P. Roberts
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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82
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Structures of the Cmr-β Complex Reveal the Regulation of the Immunity Mechanism of Type III-B CRISPR-Cas. Mol Cell 2020; 79:741-757.e7. [PMID: 32730741 DOI: 10.1016/j.molcel.2020.07.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/04/2020] [Accepted: 06/22/2020] [Indexed: 12/20/2022]
Abstract
Cmr-β is a type III-B CRISPR-Cas complex that, upon target RNA recognition, unleashes a multifaceted immune response against invading genetic elements, including single-stranded DNA (ssDNA) cleavage, cyclic oligoadenylate synthesis, and also a unique UA-specific single-stranded RNA (ssRNA) hydrolysis by the Cmr2 subunit. Here, we present the structure-function relationship of Cmr-β, unveiling how binding of the target RNA regulates the Cmr2 activities. Cryoelectron microscopy (cryo-EM) analysis revealed the unique subunit architecture of Cmr-β and captured the complex in different conformational stages of the immune response, including the non-cognate and cognate target-RNA-bound complexes. The binding of the target RNA induces a conformational change of Cmr2, which together with the complementation between the 5' tag in the CRISPR RNAs (crRNA) and the 3' antitag of the target RNA activate different configurations in a unique loop of the Cmr3 subunit, which acts as an allosteric sensor signaling the self- versus non-self-recognition. These findings highlight the diverse defense strategies of type III complexes.
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83
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Athukoralage JS, McQuarrie S, Grüschow S, Graham S, Gloster TM, White MF. Tetramerisation of the CRISPR ring nuclease Crn3/Csx3 facilitates cyclic oligoadenylate cleavage. eLife 2020; 9:e57627. [PMID: 32597755 PMCID: PMC7371418 DOI: 10.7554/elife.57627] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/28/2020] [Indexed: 12/11/2022] Open
Abstract
Type III CRISPR systems detect foreign RNA and activate the cyclase domain of the Cas10 subunit, generating cyclic oligoadenylate (cOA) molecules that act as a second messenger to signal infection, activating nucleases that degrade the nucleic acid of both invader and host. This can lead to dormancy or cell death; to avoid this, cells need a way to remove cOA from the cell once a viral infection has been defeated. Enzymes specialised for this task are known as ring nucleases, but are limited in their distribution. Here, we demonstrate that the widespread CRISPR associated protein Csx3, previously described as an RNA deadenylase, is a ring nuclease that rapidly degrades cyclic tetra-adenylate (cA4). The enzyme has an unusual cooperative reaction mechanism involving an active site that spans the interface between two dimers, sandwiching the cA4 substrate. We propose the name Crn3 (CRISPR associated ring nuclease 3) for the Csx3 family.
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Affiliation(s)
- Januka S Athukoralage
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
| | - Stuart McQuarrie
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
| | - Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
| | - Shirley Graham
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St AndrewsSt AndrewsUnited Kingdom
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84
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Shmakov SA, Wolf YI, Savitskaya E, Severinov KV, Koonin EV. Mapping CRISPR spaceromes reveals vast host-specific viromes of prokaryotes. Commun Biol 2020; 3:321. [PMID: 32572116 PMCID: PMC7308287 DOI: 10.1038/s42003-020-1014-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/15/2020] [Indexed: 12/04/2022] Open
Abstract
CRISPR arrays contain spacers, some of which are homologous to genome segments of viruses and other parasitic genetic elements and are employed as portion of guide RNAs to recognize and specifically inactivate the target genomes. However, the fraction of the spacers in sequenced CRISPR arrays that reliably match protospacer sequences in genomic databases is small, leaving the question of the origin(s) open for the great majority of the spacers. Here, we extend the spacer analysis by examining the distribution of partial matches (matching k-mers) between spacers and genomes of viruses infecting the given host as well as the host genomes themselves. The results indicate that most of the spacers originate from the host-specific viromes, whereas self-targeting is strongly selected against. However, we present evidence that the vast majority of the viruses comprising the viromes currently remain unknown although they are likely to be related to identified viruses.
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Affiliation(s)
- Sergey A Shmakov
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA
| | | | - Konstantin V Severinov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
- Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway, New Jersey, 08854, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, 20894, USA.
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85
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Sasnauskas G, Siksnys V. CRISPR adaptation from a structural perspective. Curr Opin Struct Biol 2020; 65:17-25. [PMID: 32570107 DOI: 10.1016/j.sbi.2020.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
Bacterial CRISPR-Cas systems provide adaptive immunity against viruses and other mobile genome elements. During the adaptation step cells become immunized by insertion of short fragments of foreign DNA, termed spacers, into the genomic region called a CRISPR array. Selection, processing and insertion of new spacers is an elaborate and precisely orchestrated reaction, which relies on the Cas1-Cas2 integrase complex and accessory proteins that vary among different types of CRISPR-Cas systems. This review focuses on CRISPR adaptation from the structural perspective, with the spotlight on adaptation proteins employed by type I and type II CRISPR-Cas systems.
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Affiliation(s)
- Giedrius Sasnauskas
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania.
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86
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Genetic Dissection of the Type III-A CRISPR-Cas System Csm Complex Reveals Roles of Individual Subunits. Cell Rep 2020; 26:2753-2765.e4. [PMID: 30840895 DOI: 10.1016/j.celrep.2019.02.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/29/2018] [Accepted: 02/07/2019] [Indexed: 12/26/2022] Open
Abstract
The type III-A Csm complex of Streptococcus thermophilus (StCsm) provides immunity against invading nucleic acids through the coordinated action of three catalytic domains: RNase (Csm3), ssDNase (Cas10-HD), and cyclic oligoadenylates synthase (Cas10-Palm). The matured StCsm complex is composed of Cas10:Csm2:Csm3:Csm4:Csm5 subunits and 40-nt CRISPR RNA (crRNA). We have carried out gene disruptions for each subunit and isolated deletion complexes to reveal the role of individual subunits in complex assembly and function. We show that the Cas10-Csm4 subcomplex binds the 5'-handle of crRNA and triggers Csm3 oligomerization to form a padlock for crRNA binding. We demonstrate that Csm5 plays a key role in target RNA binding while Csm2 ensures RNA cleavage at multiple sites by Csm3. Finally, guided by deletion analysis, we engineered a minimal Csm complex containing only the Csm3, Csm4, and Cas10 subunits and crRNA and demonstrated that it retains all three catalytic activities, thus paving the way for practical applications.
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87
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Roberts A, Barrangou R. Applications of CRISPR-Cas systems in lactic acid bacteria. FEMS Microbiol Rev 2020; 44:523-537. [DOI: 10.1093/femsre/fuaa016] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/18/2020] [Indexed: 12/26/2022] Open
Abstract
ABSTRACT
As a phenotypically and phylogenetically diverse group, lactic acid bacteria are found in a variety of natural environments and occupy important roles in medicine, biotechnology, food and agriculture. The widespread use of lactic acid bacteria across these industries fuels the need for new and functionally diverse strains that may be utilized as starter cultures or probiotics. Originally characterized in lactic acid bacteria, CRISPR-Cas systems and derived molecular machines can be used natively or exogenously to engineer new strains with enhanced functional attributes. Research on CRISPR-Cas biology and its applications has exploded over the past decade with studies spanning from the initial characterization of CRISPR-Cas immunity in Streptococcus thermophilus to the use of CRISPR-Cas for clinical gene therapies. Here, we discuss CRISPR-Cas classification, overview CRISPR biology and mechanism of action, and discuss current and future applications in lactic acid bacteria, opening new avenues for their industrial exploitation and manipulation of microbiomes.
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Affiliation(s)
- Avery Roberts
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Campus Box 7624, Raleigh, NC 27695, USA
- Genomic Sciences Graduate Program, North Carolina State University, Campus Box 7566, Raleigh, NC 27695, USA
| | - Rodolphe Barrangou
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Campus Box 7624, Raleigh, NC 27695, USA
- Genomic Sciences Graduate Program, North Carolina State University, Campus Box 7566, Raleigh, NC 27695, USA
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88
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Abstract
CRISPR-Cas systems have been engineered as powerful tools to control gene expression in bacteria. The most common strategy relies on the use of Cas effectors modified to bind target DNA without introducing DNA breaks. These effectors can either block the RNA polymerase or recruit it through activation domains. Here, we discuss the mechanistic details of how Cas effectors can modulate gene expression by blocking transcription initiation or acting as transcription roadblocks. CRISPR-Cas tools can be further engineered to obtain fine-tuned control of gene expression or target multiple genes simultaneously. Several caveats in using these tools have also been revealed, including off-target effects and toxicity, making it important to understand the design rules of engineered CRISPR-Cas effectors in bacteria. Alternatively, some types of CRISPR-Cas systems target RNA and could be used to block gene expression at the posttranscriptional level. Finally, we review applications of these tools in high-throughput screens and the progress and challenges in introducing CRISPR knockdown to other species, including nonmodel bacteria with industrial or clinical relevance. A deep understanding of how CRISPR-Cas systems can be harnessed to control gene expression in bacteria and build powerful tools will certainly open novel research directions.
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Affiliation(s)
- Antoine Vigouroux
- Synthetic Biology, Institut Pasteur, Paris, France
- Microbial Morphogenesis and Growth, Institut Pasteur, Paris, France
| | - David Bikard
- Synthetic Biology, Institut Pasteur, Paris, France
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89
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Lin J, Feng M, Zhang H, She Q. Characterization of a novel type III CRISPR-Cas effector provides new insights into the allosteric activation and suppression of the Cas10 DNase. Cell Discov 2020; 6:29. [PMID: 32411384 PMCID: PMC7214462 DOI: 10.1038/s41421-020-0160-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/19/2020] [Indexed: 02/08/2023] Open
Abstract
Antiviral defense by type III CRISPR-Cas systems relies on two distinct activities of their effectors: the RNA-activated DNA cleavage and synthesis of cyclic oligoadenylate. Both activities are featured as indiscriminate nucleic acid cleavage and subjected to the spatiotemporal regulation. To yield further insights into the involved mechanisms, we reconstituted LdCsm, a lactobacilli III-A system in Escherichia coli. Upon activation by target RNA, this immune system mediates robust DNA degradation but lacks the synthesis of cyclic oligoadenylates. Mutagenesis of the Csm3 and Cas10 conserved residues revealed that Csm3 and multiple structural domains in Cas10 function in the allosteric regulation to yield an active enzyme. Target RNAs carrying various truncations in the 3' anti-tag were designed and tested for their influence on DNA binding and DNA cleavage of LdCsm. Three distinct states of ternary LdCsm complexes were identified. In particular, binding of target RNAs carrying a single nucleotide in the 3' anti-tag to LdCsm yielded an active LdCsm DNase regardless whether the nucleotide shows a mismatch, as in the cognate target RNA (CTR), or a match, as in the noncognate target RNA (NTR), to the 5' tag of crRNA. In addition, further increasing the number of 3' anti-tag in CTR facilitated the substrate binding and enhanced the substrate degradation whereas doing the same as in NTR gradually decreased the substrate binding and eventually shut off the DNA cleavage by the enzyme. Together, these results provide the mechanistic insights into the allosteric activation and repression of LdCsm enzymes.
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Affiliation(s)
- Jinzhong Lin
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Mingxia Feng
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Heping Zhang
- Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, 010018 Hohhot, China
| | - Qunxin She
- Microbial Technology Institute and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Road, Jimo, 266237 Qingdao, Shandong China
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90
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Foster K, Grüschow S, Bailey S, White MF, Terns MP. Regulation of the RNA and DNA nuclease activities required for Pyrococcus furiosus Type III-B CRISPR-Cas immunity. Nucleic Acids Res 2020; 48:4418-4434. [PMID: 32198888 PMCID: PMC7192623 DOI: 10.1093/nar/gkaa176] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 02/28/2020] [Accepted: 03/19/2020] [Indexed: 12/25/2022] Open
Abstract
Type III CRISPR-Cas prokaryotic immune systems provide anti-viral and anti-plasmid immunity via a dual mechanism of RNA and DNA destruction. Upon target RNA interaction, Type III crRNP effector complexes become activated to cleave both target RNA (via Cas7) and target DNA (via Cas10). Moreover, trans-acting endoribonucleases, Csx1 or Csm6, can promote the Type III immune response by destroying both invader and host RNAs. Here, we characterize how the RNase and DNase activities associated with Type III-B immunity in Pyrococcus furiosus (Pfu) are regulated by target RNA features and second messenger signaling events. In vivo mutational analyses reveal that either the DNase activity of Cas10 or the RNase activity of Csx1 can effectively direct successful anti-plasmid immunity. Biochemical analyses confirmed that the Cas10 Palm domains convert ATP into cyclic oligoadenylate (cOA) compounds that activate the ribonuclease activity of Pfu Csx1. Furthermore, we show that the HEPN domain of the adenosine-specific endoribonuclease, Pfu Csx1, degrades cOA signaling molecules to provide an auto-inhibitory off-switch of Csx1 activation. Activation of both the DNase and cOA generation activities require target RNA binding and recognition of distinct target RNA 3' protospacer flanking sequences. Our results highlight the complex regulatory mechanisms controlling Type III CRISPR immunity.
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Affiliation(s)
- Kawanda Foster
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Scott Bailey
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Michael P Terns
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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91
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Athukoralage JS, Graham S, Rouillon C, Grüschow S, Czekster CM, White MF. The dynamic interplay of host and viral enzymes in type III CRISPR-mediated cyclic nucleotide signalling. eLife 2020; 9:55852. [PMID: 32338598 PMCID: PMC7213978 DOI: 10.7554/elife.55852] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/26/2020] [Indexed: 12/24/2022] Open
Abstract
Cyclic nucleotide second messengers are increasingly implicated in prokaryotic anti-viral defence systems. Type III CRISPR systems synthesise cyclic oligoadenylate (cOA) upon detecting foreign RNA, activating ancillary nucleases that can be toxic to cells, necessitating mechanisms to remove cOA in systems that operate via immunity rather than abortive infection. Previously, we demonstrated that the Sulfolobus solfataricus type III-D CRISPR complex generates cyclic tetra-adenylate (cA4), activating the ribonuclease Csx1, and showed that subsequent RNA cleavage and dissociation acts as an ‘off-switch’ for the cyclase activity. Subsequently, we identified the cellular ring nuclease Crn1, which slowly degrades cA4 to reset the system (Rouillon et al., 2018), and demonstrated that viruses can subvert type III CRISPR immunity by means of a potent anti-CRISPR ring nuclease variant AcrIII-1. Here, we present a comprehensive analysis of the dynamic interplay between these enzymes, governing cyclic nucleotide levels and infection outcomes in virus-host conflict.
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Affiliation(s)
- Januka S Athukoralage
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Shirley Graham
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Christophe Rouillon
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Clarissa M Czekster
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, United Kingdom
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92
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Garcia-Doval C, Schwede F, Berk C, Rostøl JT, Niewoehner O, Tejero O, Hall J, Marraffini LA, Jinek M. Activation and self-inactivation mechanisms of the cyclic oligoadenylate-dependent CRISPR ribonuclease Csm6. Nat Commun 2020; 11:1596. [PMID: 32221291 PMCID: PMC7101355 DOI: 10.1038/s41467-020-15334-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 02/28/2020] [Indexed: 12/26/2022] Open
Abstract
Bacterial and archaeal CRISPR-Cas systems provide RNA-guided immunity against genetic invaders such as bacteriophages and plasmids. Upon target RNA recognition, type III CRISPR-Cas systems produce cyclic-oligoadenylate second messengers that activate downstream effectors, including Csm6 ribonucleases, via their CARF domains. Here, we show that Enteroccocus italicus Csm6 (EiCsm6) degrades its cognate cyclic hexa-AMP (cA6) activator, and report the crystal structure of EiCsm6 bound to a cA6 mimic. Our structural, biochemical, and in vivo functional assays reveal how cA6 recognition by the CARF domain activates the Csm6 HEPN domains for collateral RNA degradation, and how CARF domain-mediated cA6 cleavage provides an intrinsic off-switch to limit Csm6 activity in the absence of ring nucleases. These mechanisms facilitate rapid invader clearance and ensure termination of CRISPR interference to limit self-toxicity. Upon target RNA recognition, type III CRISPR-Cas systems produce cyclic oligoadenylates that activate effectors such as Csm6 ribonucleases. Here, Garcia-Doval et al. show that Enteroccocus italicus Csm6 degrades its cyclic hexa-AMP activator, and report the crystal structure of the protein bound to an activator mimic.
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Affiliation(s)
- Carmela Garcia-Doval
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Frank Schwede
- Biolog Life Science Institute GmbH & Co. KG, Flughafendamm 9a, D-28199, Bremen, Germany
| | - Christian Berk
- Department of Chemistry and Applied Biosciences, Institute for Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zurich, Switzerland
| | - Jakob T Rostøl
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065-6399, USA
| | - Ole Niewoehner
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Oliver Tejero
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Jonathan Hall
- Department of Chemistry and Applied Biosciences, Institute for Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, CH-8093, Zurich, Switzerland
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065-6399, USA.,Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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93
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Burmistrz M, Krakowski K, Krawczyk-Balska A. RNA-Targeting CRISPR-Cas Systems and Their Applications. Int J Mol Sci 2020; 21:ijms21031122. [PMID: 32046217 PMCID: PMC7036953 DOI: 10.3390/ijms21031122] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/29/2020] [Accepted: 02/04/2020] [Indexed: 12/16/2022] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR-associated (Cas) systems have revolutionized modern molecular biology. Numerous types of these systems have been discovered to date. Many CRISPR-Cas systems have been used as a backbone for the development of potent research tools, with Cas9 being the most widespread. While most of the utilized systems are DNA-targeting, recently more and more attention is being gained by those that target RNA. Their ability to specifically recognize a given RNA sequence in an easily programmable way makes them ideal candidates for developing new research tools. In this review we summarize current knowledge on CRISPR-Cas systems which have been shown to target RNA molecules, that is type III (Csm/Cmr), type VI (Cas13), and type II (Cas9). We also present a list of available technologies based on these systems.
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94
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Structure and mechanism of a Type III CRISPR defence DNA nuclease activated by cyclic oligoadenylate. Nat Commun 2020; 11:500. [PMID: 31980625 PMCID: PMC6981274 DOI: 10.1038/s41467-019-14222-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/13/2019] [Indexed: 12/26/2022] Open
Abstract
The CRISPR system provides adaptive immunity against mobile genetic elements in prokaryotes. On binding invading RNA species, Type III CRISPR systems generate cyclic oligoadenylate (cOA) signalling molecules, potentiating a powerful immune response by activating downstream effector proteins, leading to viral clearance, cell dormancy or death. Here we describe the structure and mechanism of a cOA-activated CRISPR defence DNA endonuclease, CRISPR ancillary nuclease 1 (Can1). Can1 has a unique monomeric structure with two CRISPR associated Rossman fold (CARF) domains and two DNA nuclease-like domains. The crystal structure of the enzyme has been captured in the activated state, with a cyclic tetra-adenylate (cA4) molecule bound at the core of the protein. cA4 binding reorganises the structure to license a metal-dependent DNA nuclease activity specific for nicking of supercoiled DNA. DNA nicking by Can1 is predicted to slow down viral replication kinetics by leading to the collapse of DNA replication forks. Antiviral defence type III CRISPR systems produce cyclic oligoadenylates (cOA) as second messengers that activate downstream effectors. Here the authors present the crystal structure of the type III CRISPR defence DNA nuclease Can1 in complex with cyclic tetra-adenylate (cA4) and show that Can1 nicks supercoiled DNA.
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95
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Wimmer F, Beisel CL. CRISPR-Cas Systems and the Paradox of Self-Targeting Spacers. Front Microbiol 2020; 10:3078. [PMID: 32038537 PMCID: PMC6990116 DOI: 10.3389/fmicb.2019.03078] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas immune systems in bacteria and archaea record prior infections as spacers within each system’s CRISPR arrays. Spacers are normally derived from invasive genetic material and direct the immune system to complementary targets as part of future infections. However, not all spacers appear to be derived from foreign genetic material and instead can originate from the host genome. Their presence poses a paradox, as self-targeting spacers would be expected to induce an autoimmune response and cell death. In this review, we discuss the known frequency of self-targeting spacers in natural CRISPR-Cas systems, how these spacers can be incorporated into CRISPR arrays, and how the host can evade lethal attack. We also discuss how self-targeting spacers can become the basis for alternative functions performed by CRISPR-Cas systems that extend beyond adaptive immunity. Overall, the acquisition of genome-targeting spacers poses a substantial risk but can aid in the host’s evolution and potentially lead to or support new functionalities.
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Affiliation(s)
- Franziska Wimmer
- Helmholtz Institute for RNA-Based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-Based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.,Medical Faculty, University of Würzburg, Würzburg, Germany
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96
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Abstract
Many bacteria and archaea have the unique ability to heritably alter their genomes by incorporating small fragments of foreign DNA, called spacers, into CRISPR loci. Once transcribed and processed into individual CRISPR RNAs, spacer sequences guide Cas effector nucleases to destroy complementary, invading nucleic acids. Collectively, these two processes are known as the CRISPR-Cas immune response. In this Progress article, we review recent studies that have advanced our understanding of the molecular mechanisms underlying spacer acquisition and that have revealed a fundamental link between the two phases of CRISPR immunity that ensures optimal immunity from newly acquired spacers. Finally, we highlight important open questions and discuss the potential basic and applied impact of spacer acquisition research.
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Affiliation(s)
- Jon McGinn
- Laboratory of Bacteriology, The Rockefeller University, New York, NY, USA
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97
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Grüschow S, Athukoralage JS, Graham S, Hoogeboom T, White MF. Cyclic oligoadenylate signalling mediates Mycobacterium tuberculosis CRISPR defence. Nucleic Acids Res 2019; 47:9259-9270. [PMID: 31392987 PMCID: PMC6755085 DOI: 10.1093/nar/gkz676] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/19/2019] [Accepted: 07/30/2019] [Indexed: 12/26/2022] Open
Abstract
The CRISPR system provides adaptive immunity against mobile genetic elements (MGE) in prokaryotes. In type III CRISPR systems, an effector complex programmed by CRISPR RNA detects invading RNA, triggering a multi-layered defence that includes target RNA cleavage, licencing of an HD DNA nuclease domain and synthesis of cyclic oligoadenylate (cOA) molecules. cOA activates the Csx1/Csm6 family of effectors, which degrade RNA non-specifically to enhance immunity. Type III systems are found in diverse archaea and bacteria, including the human pathogen Mycobacterium tuberculosis. Here, we report a comprehensive analysis of the in vitro and in vivo activities of the type III-A M. tuberculosis CRISPR system. We demonstrate that immunity against MGE may be achieved predominantly via a cyclic hexa-adenylate (cA6) signalling pathway and the ribonuclease Csm6, rather than through DNA cleavage by the HD domain. Furthermore, we show for the first time that a type III CRISPR system can be reprogrammed by replacing the effector protein, which may be relevant for maintenance of immunity in response to pressure from viral anti-CRISPRs. These observations demonstrate that M. tuberculosis has a fully-functioning CRISPR interference system that generates a range of cyclic and linear oligonucleotides of known and unknown functions, potentiating fundamental and applied studies.
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Affiliation(s)
- Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Januka S Athukoralage
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Shirley Graham
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Tess Hoogeboom
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
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98
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González-Delgado A, Mestre MR, Martínez-Abarca F, Toro N. Spacer acquisition from RNA mediated by a natural reverse transcriptase-Cas1 fusion protein associated with a type III-D CRISPR-Cas system in Vibrio vulnificus. Nucleic Acids Res 2019; 47:10202-10211. [PMID: 31504832 PMCID: PMC6821258 DOI: 10.1093/nar/gkz746] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/12/2019] [Accepted: 08/20/2019] [Indexed: 12/26/2022] Open
Abstract
The association of reverse transcriptases (RTs) with CRISPR–Cas system has recently attracted interest because the RT activity appears to facilitate the RT-dependent acquisition of spacers from RNA molecules. However, our understanding of this spacer acquisition process remains limited. We characterized the in vivo acquisition of spacers mediated by an RT-Cas1 fusion protein linked to a type III-D system from Vibrio vulnificus strain YJ016, and showed that the adaptation module, consisting of the RT-Cas1 fusion, two different Cas2 proteins (A and B) and one of the two CRISPR arrays, was completely functional in a heterologous host. We found that mutations of the active site of the RT domain significantly decreased the acquisition of new spacers and showed that this RT-Cas1-associated adaptation module was able to incorporate spacers from RNA molecules into the CRISPR array. We demonstrated that the two Cas2 proteins of the adaptation module were required for spacer acquisition. Furthermore, we found that several sequence-specific features were required for the acquisition and integration of spacers derived from any region of the genome, with no bias along the 5′and 3′ends of coding sequences. This study provides new insight into the RT-Cas1 fusion protein-mediated acquisition of spacers from RNA molecules.
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Affiliation(s)
- Alejandro González-Delgado
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Mario Rodríguez Mestre
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Francisco Martínez-Abarca
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Nicolás Toro
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
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99
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Grainy J, Garrett S, Graveley BR, P Terns M. CRISPR repeat sequences and relative spacing specify DNA integration by Pyrococcus furiosus Cas1 and Cas2. Nucleic Acids Res 2019; 47:7518-7531. [PMID: 31219587 PMCID: PMC6698737 DOI: 10.1093/nar/gkz548] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 12/26/2022] Open
Abstract
Acquiring foreign spacer DNA into the CRISPR locus is an essential primary step of the CRISPR-Cas pathway in prokaryotes for developing host immunity to mobile genetic elements. Here, we investigate spacer integration in vitro using proteins from Pyrococcus furiosus and demonstrate that Cas1 and Cas2 are sufficient to accurately integrate spacers into a minimal CRISPR locus. Using high-throughput sequencing, we identified high frequency spacer integration occurring at the same CRISPR repeat border sites utilized in vivo, as well as at several non-CRISPR plasmid sequences which share features with repeats. Analysis of non-CRISPR integration sites revealed that Cas1 and Cas2 are directed to catalyze full-site spacer integration at specific DNA stretches where guanines and/or cytosines are 30 base pairs apart and the intervening sequence harbors several positionally conserved bases. Moreover, assaying a series of CRISPR repeat mutations, followed by sequencing of the integration products, revealed that the specificity of integration is primarily directed by sequences at the leader-repeat junction as well as an adenine-rich sequence block in the mid-repeat. Together, our results indicate that P. furiosus Cas1 and Cas2 recognize multiple sequence features distributed over a 30 base pair DNA region for accurate spacer integration at the CRISPR repeat.
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Affiliation(s)
- Julie Grainy
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Sandra Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Michael P Terns
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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100
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González-Delgado A, Mestre MR, Martínez-Abarca F, Toro N. Spacer acquisition from RNA mediated by a natural reverse transcriptase-Cas1 fusion protein associated with a type III-D CRISPR-Cas system in Vibrio vulnificus. Nucleic Acids Res 2019. [PMID: 31504832 DOI: 10.1093/nar/gkz746.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The association of reverse transcriptases (RTs) with CRISPR-Cas system has recently attracted interest because the RT activity appears to facilitate the RT-dependent acquisition of spacers from RNA molecules. However, our understanding of this spacer acquisition process remains limited. We characterized the in vivo acquisition of spacers mediated by an RT-Cas1 fusion protein linked to a type III-D system from Vibrio vulnificus strain YJ016, and showed that the adaptation module, consisting of the RT-Cas1 fusion, two different Cas2 proteins (A and B) and one of the two CRISPR arrays, was completely functional in a heterologous host. We found that mutations of the active site of the RT domain significantly decreased the acquisition of new spacers and showed that this RT-Cas1-associated adaptation module was able to incorporate spacers from RNA molecules into the CRISPR array. We demonstrated that the two Cas2 proteins of the adaptation module were required for spacer acquisition. Furthermore, we found that several sequence-specific features were required for the acquisition and integration of spacers derived from any region of the genome, with no bias along the 5'and 3'ends of coding sequences. This study provides new insight into the RT-Cas1 fusion protein-mediated acquisition of spacers from RNA molecules.
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Affiliation(s)
- Alejandro González-Delgado
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Mario Rodríguez Mestre
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Francisco Martínez-Abarca
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Nicolás Toro
- Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Profesor Albareda 1, 18008 Granada, Spain
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