1
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Yang H, Patel DJ. Structures, mechanisms and applications of RNA-centric CRISPR-Cas13. Nat Chem Biol 2024:10.1038/s41589-024-01593-6. [PMID: 38702571 DOI: 10.1038/s41589-024-01593-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 02/27/2024] [Indexed: 05/06/2024]
Abstract
Prokaryotes are equipped with a variety of resistance strategies to survive frequent viral attacks or invading mobile genetic elements. Among these, CRISPR-Cas surveillance systems are abundant and have been studied extensively. This Review focuses on CRISPR-Cas type VI Cas13 systems that use single-subunit RNA-guided Cas endonucleases for targeting and subsequent degradation of foreign RNA, thereby providing adaptive immunity. Notably, distinct from single-subunit DNA-cleaving Cas9 and Cas12 systems, Cas13 exhibits target RNA-activated substrate RNase activity. This Review outlines structural, biochemical and cell biological studies toward elucidation of the unique structural and mechanistic principles underlying surveillance effector complex formation, precursor CRISPR RNA (pre-crRNA) processing, self-discrimination and RNA degradation in Cas13 systems as well as insights into suppression by bacteriophage-encoded anti-CRISPR proteins and regulation by endogenous accessory proteins. Owing to its programmable ability for RNA recognition and cleavage, Cas13 provides powerful RNA targeting, editing, detection and imaging platforms with emerging biotechnological and therapeutic applications.
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Affiliation(s)
- Hui Yang
- Key Laboratory of RNA Innovation, Science and Engineering, 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, China.
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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2
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Chen F, Zhang C, Xue J, Wang F, Li Z. Molecular mechanism for target RNA recognition and cleavage of Cas13h. Nucleic Acids Res 2024:gkae324. [PMID: 38661236 DOI: 10.1093/nar/gkae324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024] Open
Abstract
RNA-targeting type VI CRISPR-Cas effectors are widely used in RNA applications. Cas13h is a recently identified subtype of Cas13 ribonuclease, with strong RNA cleavage activity and robust in vivo RNA knockdown efficiency. However, little is known regarding its biochemical properties and working mechanisms. Biochemical characterization of Cas13h1 indicated that it lacks in vitro pre-crRNA processing activity and adopts a central seed. The cleavage activity of Cas13h1 is enhanced by a R(G/A) 5'-PFS, and inhibited by tag:anti-tag RNA pairing. We determined the structures of Cas13h1-crRNA binary complex at 3.1 Å and Cas13h1-crRNA-target RNA ternary complex at 3.0 Å. The ternary complex adopts an elongated architecture, and encodes a nucleotide-binding pocket within Helical-2 domain to recognize the guanosine at the 5'-end of the target RNA. Base pairing between crRNA guide and target RNA disrupts Cas13h1-guide interactions, leading to dramatic movement of HEPN domains. Upon target RNA engagement, Cas13h1 adopts a complicated activation mechanism, including separation of HEPN catalytic residues and destabilization of the active site loop and NTD domain, to get activated. Collectively, these insights expand our understanding into Cas13 effectors.
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Affiliation(s)
- Fugen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Chendi Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Jialin Xue
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Feng Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
| | - Zhuang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei 430062, China
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3
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Ganguly C, Rostami S, Long K, Aribam SD, Rajan R. Unity among the diverse RNA-guided CRISPR-Cas interference mechanisms. J Biol Chem 2024; 300:107295. [PMID: 38641067 PMCID: PMC11127173 DOI: 10.1016/j.jbc.2024.107295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 04/21/2024] Open
Abstract
CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) systems are adaptive immune systems that protect bacteria and archaea from invading mobile genetic elements (MGEs). The Cas protein-CRISPR RNA (crRNA) complex uses complementarity of the crRNA "guide" region to specifically recognize the invader genome. CRISPR effectors that perform targeted destruction of the foreign genome have emerged independently as multi-subunit protein complexes (Class 1 systems) and as single multi-domain proteins (Class 2). These different CRISPR-Cas systems can cleave RNA, DNA, and protein in an RNA-guided manner to eliminate the invader, and in some cases, they initiate programmed cell death/dormancy. The versatile mechanisms of the different CRISPR-Cas systems to target and destroy nucleic acids have been adapted to develop various programmable-RNA-guided tools and have revolutionized the development of fast, accurate, and accessible genomic applications. In this review, we present the structure and interference mechanisms of different CRISPR-Cas systems and an analysis of their unified features. The three types of Class 1 systems (I, III, and IV) have a conserved right-handed helical filamentous structure that provides a backbone for sequence-specific targeting while using unique proteins with distinct mechanisms to destroy the invader. Similarly, all three Class 2 types (II, V, and VI) have a bilobed architecture that binds the RNA-DNA/RNA hybrid and uses different nuclease domains to cleave invading MGEs. Additionally, we highlight the mechanistic similarities of CRISPR-Cas enzymes with other RNA-cleaving enzymes and briefly present the evolutionary routes of the different CRISPR-Cas systems.
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Affiliation(s)
- Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Saadi Rostami
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Kole Long
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Swarmistha Devi Aribam
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA.
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4
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Karneyeva K, Kolesnik M, Livenskyi A, Zgoda V, Zubarev V, Trofimova A, Artamonova D, Ispolatov Y, Severinov K. Interference Requirements of Type III CRISPR-Cas Systems from Thermus thermophilus. J Mol Biol 2024; 436:168448. [PMID: 38266982 DOI: 10.1016/j.jmb.2024.168448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 01/12/2024] [Accepted: 01/13/2024] [Indexed: 01/26/2024]
Abstract
Among the diverse prokaryotic adaptive immunity mechanisms, the Type III CRISPR-Cas systems are the most complex. The multisubunit Type III effectors recognize RNA targets complementary to CRISPR RNAs (crRNAs). Target recognition causes synthesis of cyclic oligoadenylates that activate downstream auxiliary effectors, which affect cell physiology in complex and poorly understood ways. Here, we studied the ability of III-A and III-B CRISPR-Cas subtypes from Thermus thermophilus to interfere with plasmid transformation. We find that for both systems, requirements for crRNA-target complementarity sufficient for interference depend on the target transcript abundance, with more abundant targets requiring shorter complementarity segments. This result and thermodynamic calculations indicate that Type III effectors bind their targets in a simple bimolecular reaction with more extensive crRNA-target base pairing compensating for lower target abundance. Since the targeted RNA used in our work is non-essential for either the host or the plasmid, the results also establish that a certain number of target-bound effector complexes must be present in the cell to interfere with plasmid establishment. For the more active III-A system, we determine the minimal length of RNA-duplex sufficient for interference and show that the position of this minimal duplex can vary within the effector. Finally, we show that the III-A immunity is dependent on the HD nuclease domain of the Cas10 subunit. Since this domain is absent from the III-B system the result implies that the T. thermophilus III-B system must elicit a more efficient cyclic oligoadenylate-dependent response to provide the immunity.
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Affiliation(s)
- Karyna Karneyeva
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Matvey Kolesnik
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Alexei Livenskyi
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Viktor Zgoda
- Institute of Biomedical Chemistry, Moscow 119435, Russia
| | - Vasiliy Zubarev
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Anna Trofimova
- Laboratory of Molecular Genetics of Microorganisms, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Daria Artamonova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Yaroslav Ispolatov
- Departamento de Física, Center for Interdisciplinary Research in Astrophysics and Space Science, Universidad de Santiago de Chile, Victor Jara 3493, Santiago, Chile
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5
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Apostolopoulos A, Kawamoto N, Chow SYA, Tsuiji H, Ikeuchi Y, Shichino Y, Iwasaki S. dCas13-mediated translational repression for accurate gene silencing in mammalian cells. Nat Commun 2024; 15:2205. [PMID: 38467613 PMCID: PMC10928199 DOI: 10.1038/s41467-024-46412-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 02/27/2024] [Indexed: 03/13/2024] Open
Abstract
Current gene silencing tools based on RNA interference (RNAi) or, more recently, clustered regularly interspaced short palindromic repeats (CRISPR)‒Cas13 systems have critical drawbacks, such as off-target effects (RNAi) or collateral mRNA cleavage (CRISPR‒Cas13). Thus, a more specific method of gene knockdown is needed. Here, we develop CRISPRδ, an approach for translational silencing, harnessing catalytically inactive Cas13 proteins (dCas13). Owing to its tight association with mRNA, dCas13 serves as a physical roadblock for scanning ribosomes during translation initiation and does not affect mRNA stability. Guide RNAs covering the start codon lead to the highest efficacy regardless of the translation initiation mechanism: cap-dependent, internal ribosome entry site (IRES)-dependent, or repeat-associated non-AUG (RAN) translation. Strikingly, genome-wide ribosome profiling reveals the ultrahigh gene silencing specificity of CRISPRδ. Moreover, the fusion of a translational repressor to dCas13 further improves the performance. Our method provides a framework for translational repression-based gene silencing in eukaryotes.
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Grants
- JP20H05784 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H05278 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP21H05734 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP23H04268 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H05786 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP23H02415 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP20K07016 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP23K05648 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP21K15023 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP23KJ2175 MEXT | Japan Society for the Promotion of Science (JSPS)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- JP23gm6910005h0001 Japan Agency for Medical Research and Development (AMED)
- JP23gm6910005 Japan Agency for Medical Research and Development (AMED)
- JP20gm1410001 Japan Agency for Medical Research and Development (AMED)
- Pioneering Projects MEXT | RIKEN
- Pioneering Projects MEXT | RIKEN
- Exploratory Research Center on Life and Living Systems (ExCELLS), 23EX601
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Affiliation(s)
- Antonios Apostolopoulos
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan
| | - Naohiro Kawamoto
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan
| | - Siu Yu A Chow
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
| | - Hitomi Tsuiji
- Education and Research Division of Pharmacy, School of Pharmacy, Aichi Gakuin University, Nagoya, Aichi, 464-8650, Japan
| | - Yoshiho Ikeuchi
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo, 153-8505, Japan
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Institute for AI and Beyond, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yuichi Shichino
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan.
| | - Shintaro Iwasaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan.
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan.
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6
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Molina Vargas A, Sinha S, Osborn R, Arantes P, Patel A, Dewhurst S, Hardy D, Cameron A, Palermo G, O’Connell M. New design strategies for ultra-specific CRISPR-Cas13a-based RNA detection with single-nucleotide mismatch sensitivity. Nucleic Acids Res 2024; 52:921-939. [PMID: 38033324 PMCID: PMC10810210 DOI: 10.1093/nar/gkad1132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/27/2023] [Accepted: 11/09/2023] [Indexed: 12/02/2023] Open
Abstract
An increasingly pressing need for clinical diagnostics has required the development of novel nucleic acid-based detection technologies that are sensitive, fast, and inexpensive, and that can be deployed at point-of-care. Recently, the RNA-guided ribonuclease CRISPR-Cas13 has been successfully harnessed for such purposes. However, developing assays for detection of genetic variability, for example single-nucleotide polymorphisms, is still challenging and previously described design strategies are not always generalizable. Here, we expanded our characterization of LbuCas13a RNA-detection specificity by performing a combination of experimental RNA mismatch tolerance profiling, molecular dynamics simulations, protein, and crRNA engineering. We found certain positions in the crRNA-target-RNA duplex that are particularly sensitive to mismatches and establish the effect of RNA concentration in mismatch tolerance. Additionally, we determined that shortening the crRNA spacer or modifying the direct repeat of the crRNA leads to stricter specificities. Furthermore, we harnessed our understanding of LbuCas13a allosteric activation pathways through molecular dynamics and structure-guided engineering to develop novel Cas13a variants that display increased sensitivities to single-nucleotide mismatches. We deployed these Cas13a variants and crRNA design strategies to achieve superior discrimination of SARS-CoV-2 strains compared to wild-type LbuCas13a. Together, our work provides new design criteria and Cas13a variants to use in future easier-to-implement Cas13-based RNA detection applications.
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Affiliation(s)
- Adrian M Molina Vargas
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Souvik Sinha
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Raven Osborn
- Clinical and Translational Sciences Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Pablo R Arantes
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Amun Patel
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Dwight J Hardy
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Andrew Cameron
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Giulia Palermo
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
- Department of Chemistry, University of California Riverside, Riverside, CA, USA
| | - Mitchell R O’Connell
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
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7
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Sinha S, Molina Vargas A, Arantes P, Patel A, O’Connell M, Palermo G. Unveiling the RNA-mediated allosteric activation discloses functional hotspots in CRISPR-Cas13a. Nucleic Acids Res 2024; 52:906-920. [PMID: 38033317 PMCID: PMC10810222 DOI: 10.1093/nar/gkad1127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/25/2023] [Accepted: 11/09/2023] [Indexed: 12/02/2023] Open
Abstract
Cas13a is a recent addition to the CRISPR-Cas toolkit that exclusively targets RNA, which makes it a promising tool for RNA detection. It utilizes a CRISPR RNA (crRNA) to target RNA sequences and trigger a composite active site formed by two 'Higher Eukaryotes and Prokaryotes Nucleotide' (HEPN) domains, cleaving any solvent-exposed RNA. In this system, an intriguing form of allosteric communication controls the RNA cleavage activity, yet its molecular details are unknown. Here, multiple-microsecond molecular dynamics simulations are combined with graph theory to decipher this intricate activation mechanism. We show that the binding of a target RNA acts as an allosteric effector, by amplifying the communication signals over the dynamical noise through interactions of the crRNA at the buried HEPN1-2 interface. By introducing a novel Signal-to-Noise Ratio (SNR) of communication efficiency, we reveal critical allosteric residues-R377, N378, and R973-that rearrange their interactions upon target RNA binding. Alanine mutation of these residues is shown to select target RNA over an extended complementary sequence beyond guide-target duplex for RNA cleavage, establishing the functional significance of these hotspots. Collectively our findings offer a fundamental understanding of the Cas13a mechanism of action and pave new avenues for the development of highly selective RNA-based cleavage and detection tools.
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Affiliation(s)
- Souvik Sinha
- Department of Bioengineering, University of California Riverside, Riverside, CA , 92521, USA
| | - Adrian M Molina Vargas
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Pablo R Arantes
- Department of Bioengineering, University of California Riverside, Riverside, CA , 92521, USA
| | - Amun Patel
- Department of Bioengineering, University of California Riverside, Riverside, CA , 92521, USA
| | - Mitchell R O’Connell
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
- Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Giulia Palermo
- Department of Bioengineering, University of California Riverside, Riverside, CA , 92521, USA
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
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8
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Wimmer F, Englert F, Wandera KG, Alkhnbashi O, Collins S, Backofen R, Beisel C. Interrogating two extensively self-targeting Type I CRISPR-Cas systems in Xanthomonas albilineans reveals distinct anti-CRISPR proteins that block DNA degradation. Nucleic Acids Res 2024; 52:769-783. [PMID: 38015466 PMCID: PMC10810201 DOI: 10.1093/nar/gkad1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023] Open
Abstract
CRISPR-Cas systems store fragments of invader DNA as spacers to recognize and clear those same invaders in the future. Spacers can also be acquired from the host's genomic DNA, leading to lethal self-targeting. While self-targeting can be circumvented through different mechanisms, natural examples remain poorly explored. Here, we investigate extensive self-targeting by two CRISPR-Cas systems encoding 24 self-targeting spacers in the plant pathogen Xanthomonas albilineans. We show that the native I-C and I-F1 systems are actively expressed and that CRISPR RNAs are properly processed. When expressed in Escherichia coli, each Cascade complex binds its PAM-flanked DNA target to block transcription, while the addition of Cas3 paired with genome targeting induces cell killing. While exploring how X. albilineans survives self-targeting, we predicted putative anti-CRISPR proteins (Acrs) encoded within the bacterium's genome. Screening of identified candidates with cell-free transcription-translation systems and in E. coli revealed two Acrs, which we named AcrIC11 and AcrIF12Xal, that inhibit the activity of Cas3 but not Cascade of the respective system. While AcrF12Xal is homologous to AcrIF12, AcrIC11 shares sequence and structural homology with the anti-restriction protein KlcA. These findings help explain tolerance of self-targeting through two CRISPR-Cas systems and expand the known suite of DNA degradation-inhibiting Acrs.
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Affiliation(s)
- Franziska Wimmer
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Frank Englert
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Katharina G Wandera
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Omer S Alkhnbashi
- Information and Computer Science Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Intelligent Secure Systems (IRC-ISS), King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
| | - Scott P Collins
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
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9
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Oh GS, An S, Kim S. Harnessing CRISPR-Cas adaptation for RNA recording and beyond. BMB Rep 2024; 57:40-49. [PMID: 38053290 PMCID: PMC10828431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/04/2023] [Accepted: 04/04/2023] [Indexed: 12/07/2023] Open
Abstract
Prokaryotes encode clustered regularly interspaced short palindromic repeat (CRISPR) arrays and CRISPR-associated (Cas) genes as an adaptive immune machinery. CRISPR-Cas systems effectively protect hosts from the invasion of foreign enemies, such as bacteriophages and plasmids. During a process called 'adaptation', non-self-nucleic acid fragments are acquired as spacers between repeats in the host CRISPR array, to establish immunological memory. The highly conserved Cas1-Cas2 complexes function as molecular recorders to integrate spacers in a time course manner, which can subsequently be expressed as crRNAs complexed with Cas effector proteins for the RNAguided interference pathways. In some of the RNA-targeting type III systems, Cas1 proteins are fused with reverse transcriptase (RT), indicating that RT-Cas1-Cas2 complexes can acquire RNA transcripts for spacer acquisition. In this review, we summarize current studies that focus on the molecular structure and function of the RT-fused Cas1-Cas2 integrase, and its potential applications as a directional RNA-recording tool in cells. Furthermore, we highlight outstanding questions for RT-Cas1-Cas2 studies and future directions for RNA-recording CRISPR technologies. [BMB Reports 2024; 57(1): 40-49].
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Affiliation(s)
- Gyeong-Seok Oh
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
| | - Seongjin An
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- Department of Life Sciences, School of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Sungchul Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
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10
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Kimchi O, Larsen BB, Dunkley ORS, te Velthuis AJ, Myhrvold C. RNA structure modulates Cas13 activity and enables mismatch detection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.05.560533. [PMID: 37987004 PMCID: PMC10659300 DOI: 10.1101/2023.10.05.560533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The RNA-targeting CRISPR nuclease Cas13 has emerged as a powerful tool for applications ranging from nucleic acid detection to transcriptome engineering and RNA imaging1-6. Cas13 is activated by the hybridization of a CRISPR RNA (crRNA) to a complementary single-stranded RNA (ssRNA) protospacer in a target RNA1,7. Though Cas13 is not activated by double-stranded RNA (dsRNA) in vitro, it paradoxically demonstrates robust RNA targeting in environments where the vast majority of RNAs are highly structured2,8. Understanding Cas13's mechanism of binding and activation will be key to improving its ability to detect and perturb RNA; however, the mechanism by which Cas13 binds structured RNAs remains unknown9. Here, we systematically probe the mechanism of LwaCas13a activation in response to RNA structure perturbations using a massively multiplexed screen. We find that there are two distinct sequence-independent modes by which secondary structure affects Cas13 activity: structure in the protospacer region competes with the crRNA and can be disrupted via a strand-displacement mechanism, while structure in the region 3' to the protospacer has an allosteric inhibitory effect. We leverage the kinetic nature of the strand displacement process to improve Cas13-based RNA detection, enhancing mismatch discrimination by up to 50-fold and enabling sequence-agnostic mutation identification at low (<1%) allele frequencies. Our work sets a new standard for CRISPR-based nucleic acid detection and will enable intelligent and secondary-structure-guided target selection while also expanding the range of RNAs available for targeting with Cas13.
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Affiliation(s)
- Ofer Kimchi
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Benjamin B. Larsen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | - Owen R. S. Dunkley
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | | | - Cameron Myhrvold
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08544, USA
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
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11
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Wang B, Yang H. Progress of CRISPR-based programmable RNA manipulation and detection. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1804. [PMID: 37282821 DOI: 10.1002/wrna.1804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 06/08/2023]
Abstract
Prokaryotic clustered regularly interspaced short palindromic repeats and CRISPR associated (CRISPR-Cas) systems provide adaptive immunity by using RNA-guided endonucleases to recognize and eliminate invading foreign nucleic acids. Type II Cas9, type V Cas12, type VI Cas13, and type III Csm/Cmr complexes have been well characterized and developed as programmable platforms for selectively targeting and manipulating RNA molecules of interest in prokaryotic and eukaryotic cells. These Cas effectors exhibit remarkable diversity of ribonucleoprotein (RNP) composition, target recognition and cleavage mechanisms, and self discrimination mechanisms, which are leveraged for various RNA targeting applications. Here, we summarize the current understanding of mechanistic and functional characteristics of these Cas effectors, give an overview on RNA detection and manipulation toolbox established so far including knockdown, editing, imaging, modification, and mapping RNA-protein interactions, and discuss the future directions for CRISPR-based RNA targeting tools. This article is categorized under: RNA Methods > RNA Analyses in Cells RNA Processing > RNA Editing and Modification RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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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, China
| | - 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, China
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12
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Mantena S, Pillai PP, Petros BA, Welch NL, Myhrvold C, Sabeti PC, Metsky HC. Model-directed generation of CRISPR-Cas13a guide RNAs designs artificial sequences that improve nucleic acid detection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.557569. [PMID: 37786711 PMCID: PMC10541601 DOI: 10.1101/2023.09.20.557569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Generating maximally-fit biological sequences has the potential to transform CRISPR guide RNA design as it has other areas of biomedicine. Here, we introduce model-directed exploration algorithms (MEAs) for designing maximally-fit, artificial CRISPR-Cas13a guides-with multiple mismatches to any natural sequence-that are tailored for desired properties around nucleic acid diagnostics. We find that MEA-designed guides offer more sensitive detection of diverse pathogens and discrimination of pathogen variants compared to guides derived directly from natural sequences, and illuminate interpretable design principles that broaden Cas13a targeting.
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Affiliation(s)
- Sreekar Mantena
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Statistics, Harvard University, Cambridge, MA, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | | | - Brittany A. Petros
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Health Sciences and Technology, Harvard Medical School and Massachusetts Institute of Technology, Cambridge, MA, USA
- Harvard/Massachusetts Institute of Technology, MD-PhD Program, Boston, MA, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | | | - Cameron Myhrvold
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Pardis C. Sabeti
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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13
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Vargas AMM, Osborn R, Sinha S, Arantes PR, Patel A, Dewhurst S, Palermo G, O'Connell MR. New design strategies for ultra-specific CRISPR-Cas13a-based RNA-diagnostic tools with single-nucleotide mismatch sensitivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550755. [PMID: 37547020 PMCID: PMC10402140 DOI: 10.1101/2023.07.26.550755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
The pressing need for clinical diagnostics has required the development of novel nucleic acid-based detection technologies that are sensitive, fast, and inexpensive, and that can be deployed at point-of-care. Recently, the RNA-guided ribonuclease CRISPR-Cas13 has been successfully harnessed for such purposes. However, developing assays for detection of genetic variability, for example single-nucleotide polymorphisms, is still challenging and previously described design strategies are not always generalizable. Here, we expanded our characterization of LbuCas13a RNA-detection specificity by performing a combination of experimental RNA mismatch tolerance profiling, molecular dynamics simulations, protein, and crRNA engineering. We found certain positions in the crRNA-target-RNA duplex that are particularly sensitive to mismatches and establish the effect of RNA concentration in mismatch tolerance. Additionally, we determined that shortening the crRNA spacer or modifying the direct repeat of the crRNA leads to stricter specificities. Furthermore, we harnessed our understanding of LbuCas13a allosteric activation pathways through molecular dynamics and structure-guided engineering to develop novel Cas13a variants that display increased sensitivities to single-nucleotide mismatches. We deployed these Cas13a variants and crRNA design strategies to achieve superior discrimination of SARS-CoV-2 strains compared to wild-type LbuCas13a. Together, our work provides new design criteria and new Cas13a variants for easier-to-implement Cas13-based diagnostics. KEY POINTS Certain positions in the Cas13a crRNA-target-RNA duplex are particularly sensitive to mismatches.Understanding Cas13a's allosteric activation pathway allowed us to develop novel high-fidelity Cas13a variants.These Cas13a variants and crRNA design strategies achieve superior discrimination of SARS-CoV-2 strains. GRAPHICAL ABSTRACT
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14
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Sinha S, Molina Vargas AM, Arantes PR, Patel A, O'Connell MR, Palermo G. RNA-mediated Allosteric Activation in CRISPR-Cas13a. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.27.550797. [PMID: 37546822 PMCID: PMC10402131 DOI: 10.1101/2023.07.27.550797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Cas13a is a recent addition to the CRISPR-Cas toolkit that exclusively targets RNA, which makes it a promising tool for RNA detection. The protein uses a CRISPR RNA (crRNA) to target RNA sequences, which are cleaved by a composite active site formed by two 'Higher Eukaryotes and Prokaryotes Nucleotide' (HEPN) catalytic domains. In this system, an intriguing form of allosteric communication controls RNA cleavage activity, yet its molecular details are unknown. Here, multiple-microsecond molecular dynamics simulations are combined with graph theory and RNA cleavage assays to decipher this activation mechanism. We show that the binding of a target RNA acts as an allosteric effector of the spatially distant HEPN catalytic cleft, by amplifying the allosteric signals over the dynamical noise, that passes through the buried HEPN interface. Critical residues in this region - N378, R973, and R377 - rearrange their interactions upon target RNA binding, and alter allosteric signalling. Alanine mutation of these residues is experimentally shown to select target RNA over an extended complementary sequence beyond guide-target duplex, for RNA cleavage. Altogether, our findings offer a fundamental understanding of the Cas13a mechanism of action and pave new avenues for the development of more selective RNA-based cleavage and detection tools.
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15
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Chen Y, Zeng Z, She Q, Han W. The abortive infection functions of CRISPR-Cas and Argonaute. Trends Microbiol 2023; 31:405-418. [PMID: 36463018 DOI: 10.1016/j.tim.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/08/2022] [Accepted: 11/15/2022] [Indexed: 12/03/2022]
Abstract
CRISPR-Cas and prokaryotic Argonaute (pAgo) are nucleic acid (NA)-guided defense systems that protect prokaryotes against the invasion of mobile genetic elements. Previous studies established that they are directed by NA fragments (guides) to recognize invading complementary NA (targets), and that they cleave the targets to silence the invaders. Nevertheless, growing evidence indicates that many CRISPR-Cas and pAgo systems exploit the abortive infection (Abi) strategy to confer immunity. The CRISPR-Cas and pAgo Abi systems typically sense invaders using the NA recognition ability and activate various toxic effectors to kill the infected cells to prevent the invaders from spreading. This review summarizes the diverse mechanisms of these CRISPR-Cas and pAgo systems, and highlights their critical roles in the arms race between microbes and invaders.
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Affiliation(s)
- Yu Chen
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Hubei Hongshan Laboratory, Huazhong Agricultural University, 430070 Wuhan, China
| | - Zhifeng Zeng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Hubei Hongshan Laboratory, Huazhong Agricultural University, 430070 Wuhan, China
| | - Qunxin She
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, 266237, Qingdao, China
| | - Wenyuan Han
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Hubei Hongshan Laboratory, Huazhong Agricultural University, 430070 Wuhan, China.
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16
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Williams MC, Reker AE, Margolis SR, Liao J, Wiedmann M, Rojas ER, Meeske AJ. Restriction endonuclease cleavage of phage DNA enables resuscitation from Cas13-induced bacterial dormancy. Nat Microbiol 2023; 8:400-409. [PMID: 36782027 PMCID: PMC9992242 DOI: 10.1038/s41564-022-01318-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/22/2022] [Indexed: 02/15/2023]
Abstract
Type VI CRISPR systems protect against phage infection using the RNA-guided nuclease Cas13 to recognize viral messenger RNA. Upon target recognition, Cas13 cleaves phage and host transcripts non-specifically, leading to cell dormancy that is incompatible with phage propagation. However, whether and how infected cells recover from dormancy is unclear. Here we show that type VI CRISPR and DNA-cleaving restriction-modification (RM) systems frequently co-occur and synergize to clear phage infections and resuscitate cells. In the natural type VI CRISPR host Listeria seeligeri, we show that RM cleaves the phage genome, thus removing the source of phage transcripts and enabling cells to recover from Cas13-induced cellular dormancy. We find that phage infections are neutralized more effectively when Cas13 and RM systems operate together. Our work reveals that type VI CRISPR immunity is cell-autonomous and non-abortive when paired with RM, and hints at other synergistic roles for the diverse host-directed immune systems in bacteria.
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Affiliation(s)
| | - Alexandra E Reker
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Shally R Margolis
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Jingqiu Liao
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY, USA
- Graduate Field of Microbiology, Cornell University, Ithaca, NY, USA
| | - Enrique R Rojas
- Department of Biology, New York University, New York, NY, USA
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17
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Abstract
CRISPR-Cas is a widespread adaptive immune system in bacteria and archaea that protects against viral infection by targeting specific invading nucleic acid sequences. Whereas some CRISPR-Cas systems sense and cleave viral DNA, type III and type VI CRISPR-Cas systems sense RNA that results from viral transcription and perhaps invasion by RNA viruses. The sequence-specific detection of viral RNA evokes a cell-wide response that typically involves global damage to halt the infection. How can one make sense of an immune strategy that encompasses broad, collateral effects rather than specific, targeted destruction? In this Review, we summarize the current understanding of RNA-targeting CRISPR-Cas systems. We detail the composition and properties of type III and type VI systems, outline the cellular defence processes that are instigated upon viral RNA sensing and describe the biological rationale behind the broad RNA-activated immune responses as an effective strategy to combat viral infection.
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18
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RNA targeting unleashes indiscriminate nuclease activity of CRISPR-Cas12a2. Nature 2023; 613:582-587. [PMID: 36599980 PMCID: PMC9849127 DOI: 10.1038/s41586-022-05560-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/11/2022] [Indexed: 01/06/2023]
Abstract
Cas12a2 is a CRISPR-associated nuclease that performs RNA-guided, sequence-nonspecific degradation of single-stranded RNA, single-stranded DNA and double-stranded DNA following recognition of a complementary RNA target, culminating in abortive infection1. Here we report structures of Cas12a2 in binary, ternary and quaternary complexes to reveal a complete activation pathway. Our structures reveal that Cas12a2 is autoinhibited until binding a cognate RNA target, which exposes the RuvC active site within a large, positively charged cleft. Double-stranded DNA substrates are captured through duplex distortion and local melting, stabilized by pairs of 'aromatic clamp' residues that are crucial for double-stranded DNA degradation and in vivo immune system function. Our work provides a structural basis for this mechanism of abortive infection to achieve population-level immunity, which can be leveraged to create rational mutants that degrade a spectrum of collateral substrates.
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19
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Zhao L, Qiu M, Li X, Yang J, Li J. CRISPR-Cas13a system: A novel tool for molecular diagnostics. Front Microbiol 2022; 13:1060947. [PMID: 36569102 PMCID: PMC9772028 DOI: 10.3389/fmicb.2022.1060947] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) system is a natural adaptive immune system of prokaryotes. The CRISPR-Cas system is currently divided into two classes and six types: types I, III, and IV in class 1 systems and types II, V, and VI in class 2 systems. Among the CRISPR-Cas type VI systems, the CRISPR/Cas13a system has been the most widely characterized for its application in molecular diagnostics, gene therapy, gene editing, and RNA imaging. Moreover, because of the trans-cleavage activity of Cas13a and the high specificity of its CRISPR RNA, the CRISPR/Cas13a system has enormous potential in the field of molecular diagnostics. Herein, we summarize the applications of the CRISPR/Cas13a system in the detection of pathogens, including viruses, bacteria, parasites, chlamydia, and fungus; biomarkers, such as microRNAs, lncRNAs, and circRNAs; and some non-nucleic acid targets, including proteins, ions, and methyl groups. Meanwhile, we highlight the working principles of some novel Cas13a-based detection methods, including the Specific High-Sensitivity Enzymatic Reporter UnLOCKing (SHERLOCK) and its improved versions, Cas13a-based nucleic acid amplification-free biosensors, and Cas13a-based biosensors for non-nucleic acid target detection. Finally, we focus on some issues that need to be solved and the development prospects of the CRISPR/Cas13a system.
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Affiliation(s)
- Lixin Zhao
- Department of Biosafety, School of Basic Medicine, Army Medical University, Chongqing, China,Institute of Immunology, PLA, Army Medical University, Chongqing, China
| | - Minyue Qiu
- Department of Biosafety, School of Basic Medicine, Army Medical University, Chongqing, China,Institute of Immunology, PLA, Army Medical University, Chongqing, China
| | - Xiaojia Li
- Department of Biosafety, School of Basic Medicine, Army Medical University, Chongqing, China
| | - Juanzhen Yang
- Department of Biosafety, School of Basic Medicine, Army Medical University, Chongqing, China
| | - Jintao Li
- Department of Biosafety, School of Basic Medicine, Army Medical University, Chongqing, China,Institute of Immunology, PLA, Army Medical University, Chongqing, China,*Correspondence: Jintao Li,
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20
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Bot JF, van der Oost J, Geijsen N. The double life of CRISPR-Cas13. Curr Opin Biotechnol 2022; 78:102789. [PMID: 36115160 DOI: 10.1016/j.copbio.2022.102789] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/25/2022] [Accepted: 08/07/2022] [Indexed: 12/14/2022]
Abstract
Since the discovery of RNA-programmable nucleases from the prokaryotic adaptive immune system CRISPR-Cas, these proteins have seen rapid and widespread adoption for biotechnological and clinical research. A recently discovered system, CRISPR-Cas13, uses CRISPR RNA guides to target RNA. Interestingly, RNA targeting by Cas13 results in cleavage of both target RNA and bystander RNA. This feature has been used to develop innovative diagnostic tools for the detection of specific RNAs. Unlike in vitro detection of RNA using collateral RNA cleavage, however, initial studies of mammalian cells only revealed highly specific target RNA-knockdown activity. Although these findings have been confirmed subsequently, several recent publications do report Cas13-mediated toxicity and collateral RNA cleavage when using Cas13 in eukaryotes. Here, we review these conflicting observations and discuss its potential molecular basis.
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Affiliation(s)
- Jorik F Bot
- Dept. of Anatomy & Embryology, Leiden University Medical Center, Einthovenweg 20, 2300 RC Leiden, the Netherlands; The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden node, the Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, the Netherlands
| | - Niels Geijsen
- Dept. of Anatomy & Embryology, Leiden University Medical Center, Einthovenweg 20, 2300 RC Leiden, the Netherlands; The Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Leiden node, the Netherlands.
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21
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Wu S, Tian P, Tan T. CRISPR-Cas13 technology portfolio and alliance with other genetic tools. Biotechnol Adv 2022; 61:108047. [DOI: 10.1016/j.biotechadv.2022.108047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/03/2022] [Accepted: 09/29/2022] [Indexed: 11/02/2022]
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22
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Bacteriophage genome engineering with CRISPR-Cas13a. Nat Microbiol 2022; 7:1956-1966. [PMID: 36316452 PMCID: PMC9722621 DOI: 10.1038/s41564-022-01243-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/02/2022] [Indexed: 12/05/2022]
Abstract
Jumbo phages such as Pseudomonas aeruginosa ФKZ have potential as antimicrobials and as a model for uncovering basic phage biology. Both pursuits are currently limited by a lack of genetic engineering tools due to a proteinaceous 'phage nucleus' structure that protects from DNA-targeting CRISPR-Cas tools. To provide reverse-genetics tools for DNA jumbo phages from this family, we combined homologous recombination with an RNA-targeting CRISPR-Cas13a enzyme and used an anti-CRISPR gene (acrVIA1) as a selectable marker. We showed that this process can insert foreign genes, delete genes and add fluorescent tags to genes in the ФKZ genome. Fluorescent tagging of endogenous gp93 revealed that it is ejected with the phage DNA while deletion of the tubulin-like protein PhuZ surprisingly had only a modest impact on phage burst size. Editing of two other phages that resist DNA-targeting CRISPR-Cas systems was also achieved. RNA-targeting Cas13a holds great promise for becoming a universal genetic editing tool for intractable phages, enabling the systematic study of phage genes of unknown function.
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23
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Recent advances on CRISPR/Cas system-enabled portable detection devices for on-site agri-food safety assay. Trends Food Sci Technol 2022. [DOI: 10.1016/j.tifs.2022.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Goswami HN, Rai J, Das A, Li H. Molecular mechanism of active Cas7-11 in processing CRISPR RNA and interfering target RNA. eLife 2022; 11:e81678. [PMID: 36190192 PMCID: PMC9629832 DOI: 10.7554/elife.81678] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/30/2022] [Indexed: 01/14/2023] Open
Abstract
Cas7-11 is a Type III-E CRISPR Cas effector that confers programmable RNA cleavage and has potential applications in RNA interference. Cas7-11 encodes a single polypeptide containing four Cas7- and one Cas11-like segments that obscures the distinction between the multi-subunit Class 1 and the single-subunit Class-2 CRISPR Cas systems. We report a cryo-EM (cryo-electron microscopy) structure of the active Cas7-11 from Desulfonema ishimotonii (DiCas7-11) that reveals the molecular basis for RNA processing and interference activities. DiCas7-11 arranges its Cas7- and Cas11-like domains in an extended form that resembles the backbone made up by four Cas7 and one Cas11 subunits in the multi-subunit enzymes. Unlike the multi-subunit enzymes, however, the backbone of DiCas7-11 contains evolutionarily different Cas7 and Cas11 domains, giving rise to their unique functionality. The first Cas7-like domain nearly engulfs the last 15 direct repeat nucleotides in processing and recognition of the CRISPR RNA, and its free-standing fragment retains most of the activity. Both the second and the third Cas7-like domains mediate target RNA cleavage in a metal-dependent manner. The structure and mutational data indicate that the long variable insertion to the fourth Cas7 domain has little impact on RNA processing or targeting, suggesting the possibility for engineering a compact and programmable RNA interference tool.
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Affiliation(s)
- Hemant N Goswami
- Institute of Molecular Biophysics, Florida State UniversityTallahasseeUnited States
| | - Jay Rai
- Institute of Molecular Biophysics, Florida State UniversityTallahasseeUnited States
| | - Anuska Das
- Institute of Molecular Biophysics, Florida State UniversityTallahasseeUnited States
| | - Hong Li
- Institute of Molecular Biophysics, Florida State UniversityTallahasseeUnited States
- Department of Chemistry and Biochemistry, Florida State UniversityTallahasseeUnited States
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25
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Vialetto E, Yu Y, Collins SP, Wandera KG, Barquist L, Beisel CL. A target expression threshold dictates invader defense and prevents autoimmunity by CRISPR-Cas13. Cell Host Microbe 2022; 30:1151-1162.e6. [PMID: 35690065 PMCID: PMC9590104 DOI: 10.1016/j.chom.2022.05.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/30/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022]
Abstract
CRISPR-Cas systems must enact robust immunity against foreign genetic material without inducing cytotoxic autoimmunity. For type VI systems that use Cas13 nucleases and recognize RNA targets, immune activation requires extensive CRISPR RNA (crRNA) guide-target complementarity and a target-flanking motif. Here, we report a third requirement shaping the immune response: the expression of the target transcript exceeding a threshold. We found that endogenous non-essential transcripts targeted by crRNAs rarely elicited autoimmunity. Instead, autoimmune induction required over-expressing the targeted transcripts above a threshold. A genome-wide screen confirmed target expression levels as a global determinant of cytotoxic autoimmunity and revealed that this threshold shifts with each guide-target pair. This threshold further ensured defense against a lytic bacteriophage yet allowed the tolerance of a targeted beneficial gene expressed from an invading plasmid. These findings establish target expression levels as an additional criterion for immune defense by RNA-targeting CRISPR-Cas systems, preventing autoimmunity and distinguishing pathogenic and benign invaders.
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Affiliation(s)
- Elena Vialetto
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Yanying Yu
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Scott P Collins
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Katharina G Wandera
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Lars Barquist
- 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
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA; Medical Faculty, University of Würzburg, 97080 Würzburg, Germany.
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26
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Liu X, Kang X, Lei C, Ren W, Liu C. Programming the trans-cleavage Activity of CRISPR-Cas13a by Single-Strand DNA Blocker and Its Biosensing Application. Anal Chem 2022; 94:3987-3996. [PMID: 35193353 DOI: 10.1021/acs.analchem.1c05124] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The precise and controllable programming of the trans-cleavage activity of the CRISPR-Cas13a systems is significant but challenging for fabricating high-performance biosensing systems toward various kinds of biomolecule targets. In this work, we have demonstrated that under a critical low Mg2+ concentration, a simple and short single-stranded DNA (ssDNA) probe free of any modification can efficiently prevent the assembly of crRNA and LwaCas13a only by partially binding with the crRNA repeat region, thereby blocking the trans-cleavage activity of the LwaCas13a system. Furthermore, we have demonstrated that the blocked trans-cleavage activity of the LwaCas13a system can be recovered by various kinds of biologically important substances as long as they could specifically release the blocker DNA from the crRNA in a target-responsive manner, providing a facile route for the quantification of diverse biomarkers such as enzymes, antigens/proteins, and exosomes. To the best of our knowledge, this is reported for the first time that a simple ssDNA can be employed as the switch element to control the crRNA structure and regulate the trans-cleavage activity of Cas13a, which has enriched the CRISPR-Cas13a sensing toolbox and will greatly expand its application scope.
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Affiliation(s)
- Xiaoling Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, P. R. China
| | - Xinyue Kang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, P. R. China
| | - Chao Lei
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, P. R. China
| | - Wei Ren
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, P. R. China
| | - Chenghui Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi, P. R. China
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27
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Structure and mechanism of the RNA dependent RNase Cas13a from Rhodobacter capsulatus. Commun Biol 2022; 5:71. [PMID: 35058543 PMCID: PMC8776769 DOI: 10.1038/s42003-022-03025-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 12/27/2021] [Indexed: 11/09/2022] Open
Abstract
Cas13a are single-molecule effectors of the Class II, Type VI family of CRISPR-Cas systems that are part of the bacterial and archaeal defense systems. These RNA-guided and RNA-activated RNA endonucleases are characterized by their ability to cleave target RNAs complementary to the crRNA-spacer sequence, as well as bystander RNAs in a sequence-unspecific manner. Due to cleavage of cellular transcripts they induce dormancy in the host cell and thus protect the bacterial population by aborting the infectious cycle of RNA-phages. Here we report the structural and functional characterization of a Cas13a enzyme from the photo-auxotrophic purple bacteria Rhodobacter capsulatus. The X-ray crystal structure of the RcCas13a-crRNA complex reveals its distinct crRNA recognition mode as well as the enzyme in its contracted, pre-activation conformation. Using site-directed mutagenesis in combination with mass spectrometry, we identified key residues responsible for pre-crRNA processing by RcCas13a in its distinct catalytic site, and elucidated the acid-base mediated cleavage reaction mechanism. In addition, RcCas13a cleaves target-RNA as well as bystander-RNAs in Escherichia coli which requires its catalytic active HEPN (higher eukaryotes and prokaryotes nucleotide binding) domain nuclease activity. Our data provide further insights into the molecular mechanisms and function of this intriguing family of RNA-dependent RNA endonucleases that are already employed as efficient tools for RNA detection and regulation of gene expression. The structure of the Cas13a RNase from the purple bacterium R. capsulatus in complex with its crRNA is reported here. The study reveals that the enzyme combines shape and sequence-specific readout to recognize its crRNA.
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28
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Alternative functions of CRISPR-Cas systems in the evolutionary arms race. Nat Rev Microbiol 2022; 20:351-364. [PMID: 34992260 DOI: 10.1038/s41579-021-00663-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2021] [Indexed: 12/14/2022]
Abstract
CRISPR-Cas systems of bacteria and archaea comprise chromosomal loci with typical repetitive clusters and associated genes encoding a range of Cas proteins. Adaptation of CRISPR arrays occurs when virus-derived and plasmid-derived sequences are integrated as new CRISPR spacers. Cas proteins use CRISPR-derived RNA guides to specifically recognize and cleave nucleic acids of invading mobile genetic elements. Apart from this role as an adaptive immune system, some CRISPR-associated nucleases are hijacked by mobile genetic elements: viruses use them to attack their prokaryotic hosts, and transposons have adopted CRISPR systems for guided transposition. In addition, some CRISPR-Cas systems control the expression of genes involved in bacterial physiology and virulence. Moreover, pathogenic bacteria may use their Cas nuclease activity indirectly to evade the human immune system or directly to invade the nucleus and damage the chromosomal DNA of infected human cells. Thus, the evolutionary arms race has led to the expansion of exciting variations in CRISPR mechanisms and functionalities. In this Review, we explore the latest insights into the diverse functions of CRISPR-Cas systems beyond adaptive immunity and discuss the implications for the development of CRISPR-based applications.
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29
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Deogharia M, Gurha P. The "guiding" principles of noncoding RNA function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 13:e1704. [PMID: 34856642 DOI: 10.1002/wrna.1704] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/09/2021] [Accepted: 11/11/2021] [Indexed: 12/25/2022]
Abstract
The human genome is pervasively transcribed and yet only a small fraction of these RNAs (less than 2%) are known to code for proteins. The vast majority of the RNAs are classified as noncoding RNAs (ncRNAs) and are further subgrouped as small (shorter than 200 bases) and long noncoding RNAs. The ncRNAs have been identified in all three domains of life and regulate diverse cellular processes through transcriptional and posttranscriptional gene regulation. Most of these RNAs work in conjunction with proteins forming a wide array of base pairing interactions. The determinants of these base pairing interactions are now becoming more evident and show striking similarities among the diverse group of ncRNAs. Here we present a mechanistic overview of pairing between RNA-RNA or RNA-DNA that dictates the function of ncRNAs; we provide examples to illustrate that ncRNAs work through shared evolutionary mechanisms that encompasses a guide-target interaction, involving not only classical Watson-Crick but also noncanonical Wobble and Hoogsteen base pairing. We also highlight the similarities in target selection, proofreading, and the ruler mechanism of ncRNA-protein complexes that confers target specificity and target site selection. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA-Based Catalysis > RNA-Mediated Cleavage RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution.
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Affiliation(s)
- Manisha Deogharia
- Center for Cardiovascular Genetics, Institute of Molecular Medicine, Houston, Texas, USA.,University of Texas Health Sciences Center at Houston, Houston, Texas, USA
| | - Priyatansh Gurha
- Center for Cardiovascular Genetics, Institute of Molecular Medicine, Houston, Texas, USA.,University of Texas Health Sciences Center at Houston, Houston, Texas, USA
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30
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Abstract
CRISPR-Cas adaptive immune systems in bacteria and archaea utilize short CRISPR RNAs (crRNAs) to guide sequence-specific recognition and clearance of foreign genetic material. Multiple crRNAs are stored together in a compact format called a CRISPR array that is transcribed and processed into the individual crRNAs. While the exact processing mechanisms vary widely, some CRISPR-Cas systems, including those encoding the Cas9 nuclease, rely on a trans-activating crRNA (tracrRNA). The tracrRNA was discovered in 2011 and was quickly co-opted to create single-guide RNAs as core components of CRISPR-Cas9 technologies. Since then, further studies have uncovered processes extending beyond the traditional role of tracrRNA in crRNA biogenesis, revealed Cas nucleases besides Cas9 that are dependent on tracrRNAs, and established new applications based on tracrRNA engineering. In this review, we describe the biology of the tracrRNA and how its ongoing characterization has garnered new insights into prokaryotic immune defense and enabled key technological advances.
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Affiliation(s)
- Chunyu Liao
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany;
| | - Chase L Beisel
- 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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31
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Wang Y, Mao T, Li Y, Xiao W, Liang X, Duan G, Yang H. Characterization of 67 Confirmed Clustered Regularly Interspaced Short Palindromic Repeats Loci in 52 Strains of Staphylococci. Front Microbiol 2021; 12:736565. [PMID: 34751223 PMCID: PMC8571024 DOI: 10.3389/fmicb.2021.736565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/27/2021] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus (S. aureus), which is one of the most important species of Staphylococci, poses a great threat to public health. Clustered regularly interspaced short palindromic repeats (CRISPR) and their CRISPR-associated proteins (Cas) are an adaptive immune platform to combat foreign mobile genetic elements (MGEs) such as plasmids and phages. The aim of this study is to describe the distribution and structure of CRISPR-Cas system in S. aureus, and to explore the relationship between CRISPR and horizontal gene transfer (HGT). Here, we analyzed 67 confirmed CRISPR loci and 15 companion Cas proteins in 52 strains of Staphylococci with bioinformatics methods. Comparing with the orphan CRISPR loci in Staphylococci, the strains harboring complete CRISPR-Cas systems contained multiple CRISPR loci, direct repeat sequences (DR) forming stable RNA secondary structures with lower minimum free energy (MFE), and variable spacers with detectable protospacers. In S. aureus, unlike the orphan CRISPRs away from Staphylococcal cassette chromosome mec (SCCmec), the complete CRISPR-Cas systems were in J1 region of SCCmec. In addition, we found a conserved motif 5'-TTCTCGT-3' that may protect their downstream sequences from DNA interference. In general, orphan CRISPR locus in S. aureus differed greatly from the structural characteristics of the CRISPR-Cas system. Collectively, our results provided new insight into the diversity and characterization of the CRISPR-Cas system in S. aureus.
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Affiliation(s)
- Ying Wang
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Tingting Mao
- The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yinxia Li
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Wenwei Xiao
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Xuan Liang
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Guangcai Duan
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Haiyan Yang
- College of Public Health, Zhengzhou University, Zhengzhou, China
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32
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Kolesnik MV, Fedorova I, Karneyeva KA, Artamonova DN, Severinov KV. Type III CRISPR-Cas Systems: Deciphering the Most Complex Prokaryotic Immune System. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1301-1314. [PMID: 34903162 PMCID: PMC8527444 DOI: 10.1134/s0006297921100114] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 12/18/2022]
Abstract
The emergence and persistence of selfish genetic elements is an intrinsic feature of all living systems. Cellular organisms have evolved a plethora of elaborate defense systems that limit the spread of such genetic parasites. CRISPR-Cas are RNA-guided defense systems used by prokaryotes to recognize and destroy foreign nucleic acids. These systems acquire and store fragments of foreign nucleic acids and utilize the stored sequences as guides to recognize and destroy genetic invaders. CRISPR-Cas systems have been extensively studied, as some of them are used in various genome editing technologies. Although Type III CRISPR-Cas systems are among the most common CRISPR-Cas systems, they are also some of the least investigated ones, mostly due to the complexity of their action compared to other CRISPR-Cas system types. Type III effector complexes specifically recognize and cleave RNA molecules. The recognition of the target RNA activates the effector large subunit - the so-called CRISPR polymerase - which cleaves DNA and produces small cyclic oligonucleotides that act as signaling molecules to activate auxiliary effectors, notably non-specific RNases. In this review, we provide a historical overview of the sometimes meandering pathway of the Type III CRISPR research. We also review the current data on the structures and activities of Type III CRISPR-Cas systems components, their biological roles, and evolutionary history. Finally, using structural modeling with AlphaFold2, we show that the archaeal HRAMP signature protein, which heretofore has had no assigned function, is a degenerate relative of Type III CRISPR-Cas signature protein Cas10, suggesting that HRAMP systems have descended from Type III CRISPR-Cas systems or their ancestors.
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Affiliation(s)
- Matvey V Kolesnik
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia.
| | - Iana Fedorova
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 195251, Russia.
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Karyna A Karneyeva
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia.
| | - Daria N Artamonova
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia.
| | - Konstantin V Severinov
- Center of Life Science, Skolkovo Institute of Science and Technology, Moscow, 121205, Russia.
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
- Waksman Institute of Microbiology, Piscataway, NJ 08854, USA
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33
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Kordyś M, Sen R, Warkocki Z. Applications of the versatile CRISPR-Cas13 RNA targeting system. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1694. [PMID: 34553495 DOI: 10.1002/wrna.1694] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/26/2022]
Abstract
CRISPR-Cas are adaptable natural prokaryotic defense systems that act against invading viruses and plasmids. Among the six currently known major CRISPR-Cas types, the type VI CRISPR-Cas13 is the only one known to exclusively bind and cleave foreign RNA. Within the last couple of years, this system has been adapted to serve numerous, and sometimes not obvious, applications, including some that might be developed as effective molecular therapies. Indeed, Cas13 has been adapted to kill antibiotic-resistant bacteria. In a cell-free environment, Cas13 has been used in the development of highly specific, sensitive, multiplexing-capable, and field-adaptable detection tools. Importantly, Cas13 can be reprogrammed and applied to eukaryotes to either combat pathogenic RNA viruses or in the regulation of gene expression, facilitating the knockdown of mRNA, circular RNA, and noncoding RNA. Furthermore, Cas13 has been harnessed for in vivo RNA modifications including programmable regulation of alternative splicing, A-to-I and C to U editing, and m6A modifications. Finally, approaches allowing for the detection and characterization of RNA-interacting proteins have also been demonstrated. Here, we provide a comprehensive overview of the applications utilizing CRISPR-Cas13 that illustrate its versatility. We also discuss the most important limitations of the CRISPR-Cas13-based technologies, and controversies regarding them. This article is categorized under: RNA Methods > RNA Analyses in Cells RNA Processing > RNA Editing and Modification RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Martyna Kordyś
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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34
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Guzmán NM, Esquerra-Ruvira B, Mojica FJM. Digging into the lesser-known aspects of CRISPR biology. Int Microbiol 2021; 24:473-498. [PMID: 34487299 PMCID: PMC8616872 DOI: 10.1007/s10123-021-00208-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/26/2022]
Abstract
A long time has passed since regularly interspaced DNA repeats were discovered in prokaryotes. Today, those enigmatic repetitive elements termed clustered regularly interspaced short palindromic repeats (CRISPR) are acknowledged as an emblematic part of multicomponent CRISPR-Cas (CRISPR associated) systems. These systems are involved in a variety of roles in bacteria and archaea, notably, that of conferring protection against transmissible genetic elements through an adaptive immune-like response. This review summarises the present knowledge on the diversity, molecular mechanisms and biology of CRISPR-Cas. We pay special attention to the most recent findings related to the determinants and consequences of CRISPR-Cas activity. Research on the basic features of these systems illustrates how instrumental the study of prokaryotes is for understanding biology in general, ultimately providing valuable tools for diverse fields and fuelling research beyond the mainstream.
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Affiliation(s)
- Noemí M Guzmán
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Belén Esquerra-Ruvira
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Francisco J M Mojica
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain. .,Instituto Multidisciplinar para el Estudio del Medio, Universidad de Alicante, Alicante, Spain.
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35
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Abstract
Control of pathogenic bacteria by deliberate application of predatory phages has potential as a powerful therapy against antibiotic-resistant bacteria. The key advantages of phage biocontrol over antibacterial chemotherapy are: (1) an ability to self-propagate inside host bacteria, (2) targeted predation of specific species or strains of bacteria, (3) adaptive molecular machinery to overcome resistance in target bacteria. However, realizing the potential of phage biocontrol is dependent on harnessing or adapting these responses, as many phage species switch between lytic infection cycles (resulting in lysis) and lysogenic infection cycles (resulting in genomic integration) that increase the likelihood of survival of the phage in response to external stress or host depletion. Similarly, host range will need to be optimized to make phage therapy medically viable whilst avoiding the potential for deleteriously disturbing the commensal microbiota. Phage training is a new approach to produce efficient phages by capitalizing on the evolved response of wild-type phages to bacterial resistance. Here we will review recent studies reporting successful trials of training different strains of phages to switch into lytic replication mode, overcome bacterial resistance, and increase their host range. This review will also highlight the current knowledge of phage training and future implications in phage applications and phage therapy and summarize the recent pipeline of the magistral preparation to produce a customized phage for clinical trials and medical applications.
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36
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Perčulija V, Lin J, Zhang B, Ouyang S. Functional Features and Current Applications of the RNA-Targeting Type VI CRISPR-Cas Systems. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004685. [PMID: 34254038 PMCID: PMC8209922 DOI: 10.1002/advs.202004685] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/26/2021] [Indexed: 05/14/2023]
Abstract
CRISPR-Cas systems are a form of prokaryotic adaptive immunity that employs RNA-guided endonucleases (Cas effectors) to cleave foreign genetic elements. Due to their simplicity, targeting programmability, and efficiency, single-effector CRISPR-Cas systems have great potential for application in research, biotechnology, and therapeutics. While DNA-targeting Cas effectors such as Cas9 and Cas12a have become indispensable tools for genome editing in the past decade, the more recent discovery of RNA-targeting CRISPR-Cas systems has opened the door for implementation of CRISPR-Cas technology in RNA manipulation. With an increasing number of studies reporting their application in transcriptome engineering, viral interference, nucleic acid detection, and RNA imaging, type VI CRISPR-Cas systems and the associated Cas13 effectors particularly hold promise as RNA-targeting or RNA-binding tools. However, even though previous structural and biochemical characterization provided a firm basis for leveraging type VI CRISPR-Cas systems into such tools, the lack of comprehension of certain mechanisms underlying their functions hinders more sophisticated and conventional use. This review will summarize current knowledge on structural and mechanistic properties of type VI CRISPR-Cas systems, give an overview on the reported applications, and discuss functional features that need further investigation in order to improve performance of Cas13-based tools.
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Affiliation(s)
- Vanja Perčulija
- The Key Laboratory of Innate Immune Biology of Fujian ProvinceProvincial University Key Laboratory of Cellular Stress Response and Metabolic RegulationBiomedical Research Center of South ChinaKey Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of EducationCollege of Life SciencesFujian Normal UniversityFuzhou350117China
- International College of Chinese StudiesFujian Normal UniversityFuzhou350117China
| | - Jinying Lin
- The Key Laboratory of Innate Immune Biology of Fujian ProvinceProvincial University Key Laboratory of Cellular Stress Response and Metabolic RegulationBiomedical Research Center of South ChinaKey Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of EducationCollege of Life SciencesFujian Normal UniversityFuzhou350117China
| | - Bo Zhang
- The Key Laboratory of Innate Immune Biology of Fujian ProvinceProvincial University Key Laboratory of Cellular Stress Response and Metabolic RegulationBiomedical Research Center of South ChinaKey Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of EducationCollege of Life SciencesFujian Normal UniversityFuzhou350117China
| | - Songying Ouyang
- The Key Laboratory of Innate Immune Biology of Fujian ProvinceProvincial University Key Laboratory of Cellular Stress Response and Metabolic RegulationBiomedical Research Center of South ChinaKey Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of EducationCollege of Life SciencesFujian Normal UniversityFuzhou350117China
- Laboratory for Marine Biology and BiotechnologyPilot National Laboratory for Marine Science and Technology (Qingdao)Qingdao266237China
- National Laboratory of BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijing100101China
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37
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Palaz F, Kalkan AK, Can Ö, Demir AN, Tozluyurt A, Özcan A, Ozsoz M. CRISPR-Cas13 System as a Promising and Versatile Tool for Cancer Diagnosis, Therapy, and Research. ACS Synth Biol 2021; 10:1245-1267. [PMID: 34037380 DOI: 10.1021/acssynbio.1c00107] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Over the past decades, significant progress has been made in targeted cancer therapy. In precision oncology, molecular profiling of cancer patients enables the use of targeted cancer therapeutics. However, current diagnostic methods for molecular analysis of cancer are costly and require sophisticated equipment. Moreover, targeted cancer therapeutics such as monoclonal antibodies and small-molecule drugs may cause off-target effects and they are available for only a minority of cancer driver proteins. Therefore, there is still a need for versatile, efficient, and precise tools for cancer diagnostics and targeted cancer treatment. In recent years, the CRISPR-based genome and transcriptome engineering toolbox has expanded rapidly. Particularly, the RNA-targeting CRISPR-Cas13 system has unique biochemical properties, making Cas13 a promising tool for cancer diagnosis, therapy, and research. Cas13-based diagnostic methods allow early detection and monitoring of cancer markers from liquid biopsy samples without the need for complex instrumentation. In addition, Cas13 can be used for targeted cancer therapy through degrading and manipulating cancer-associated transcripts with high efficiency and specificity. Moreover, Cas13-mediated programmable RNA manipulation tools offer invaluable opportunities for cancer research, identification of drug-resistance mechanisms, and discovery of novel therapeutic targets. Here, we review and discuss the current use and potential applications of the CRISPR-Cas13 system in cancer diagnosis, therapy, and research. Thus, researchers will gain a deep understanding of CRISPR-Cas13 technologies, which have the potential to be used as next-generation cancer diagnostics and therapeutics.
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Affiliation(s)
- Fahreddin Palaz
- Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | | | - Özgür Can
- Department of Molecular Biology and Genetics, Koc University, Istanbul 34450, Turkey
| | - Ayça Nur Demir
- Faculty of Medicine, Afyonkarahisar Health Sciences University, Afyonkarahisar 03100, Turkey
| | - Abdullah Tozluyurt
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - Ahsen Özcan
- Institute of Genetic Engineering and Biotechnology, TUBITAK Marmara Research Center, Kocaeli 41470, Turkey
| | - Mehmet Ozsoz
- Department of Biomedical Engineering, Near East University, 10 Mersin, Nicosia, Turkey
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38
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Wu QW, Kapfhammer JP. Conditional gene silencing via a CRISPR system in cerebellar Purkinje cells. Biochim Biophys Acta Gen Subj 2021; 1865:129869. [PMID: 33581252 DOI: 10.1016/j.bbagen.2021.129869] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 12/26/2022]
Abstract
• Specific gene knockdown in cerebellar Purkinje cells is a major challenge because Purkinje cells only make up a small fraction of the cerebellum and off-target effects of shRNA occur.
• Little is known about the application of CRISPR-Cas13 and the resulting protein expression levels in Purkinje cells, a type of developing postmitotic neuron.
• We explored the possibility of a Cas13-mediated conditional knockdown system for cerebellar Purkinje cells. This system can achieve a suppression of the target proteins restricted to Purkinje cells in mixed cerebellar cultures.
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Affiliation(s)
- Qin-Wei Wu
- Institute of Anatomy, Department of Biomedicine, University of Basel, Pestalozzistr. 20, 4056 Basel, Switzerland.
| | - Josef P Kapfhammer
- Institute of Anatomy, Department of Biomedicine, University of Basel, Pestalozzistr. 20, 4056 Basel, Switzerland.
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39
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Abstract
Despite numerous viral outbreaks in the last decade, including a devastating global pandemic, diagnostic and therapeutic technologies remain severely lacking. CRISPR-Cas systems have the potential to address these critical needs in the response against infectious disease. Initially discovered as the bacterial adaptive immune system, these systems provide a unique opportunity to create programmable, sequence-specific technologies for detection of viral nucleic acids and inhibition of viral replication. This review summarizes how CRISPR-Cas systems-in particular the recently discovered DNA-targeting Cas12 and RNA-targeting Cas13, both possessing a unique trans-cleavage activity-are being harnessed for viral diagnostics and therapies. We further highlight the numerous technologies whose development has accelerated in response to the COVID-19 pandemic.
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Affiliation(s)
- Catherine A. Freije
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA 02142, USA,Ph.D. Program in Virology, Harvard Medical School, Boston, MA 02115, USA,Corresponding author
| | - Pardis C. Sabeti
- Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA 02142, USA,Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA,Massachusetts Consortium on Pathogen Readiness, Boston, MA 02115, USA,Corresponding author
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40
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Use of Bacteriophage Amended with CRISPR-Cas Systems to Combat Antimicrobial Resistance in the Bacterial Foodborne Pathogen Listeria monocytogenes. Antibiotics (Basel) 2021; 10:antibiotics10030308. [PMID: 33802904 PMCID: PMC8002625 DOI: 10.3390/antibiotics10030308] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 12/15/2022] Open
Abstract
Listeria monocytogenes is a bacterial foodborne pathogen and the causative agent of the disease listeriosis, which though uncommon can result in severe symptoms such as meningitis, septicemia, stillbirths, and abortions and has a high case fatality rate. This pathogen can infect humans and other animals, resulting in massive health and economic impacts in the United States and globally. Listeriosis is treated with antimicrobials, typically a combination of a beta-lactam and an aminoglycoside, and L. monocytogenes has remained largely susceptible to the drugs of choice. However, there are several reports of antimicrobial resistance (AMR) in both L. monocytogenes and other Listeria species. Given the dire health outcomes associated with listeriosis, the prospect of antimicrobial-resistant L. monocytogenes is highly problematic for human and animal health. Developing effective tools for the control and elimination of L. monocytogenes, including strains with antimicrobial resistance, is of the utmost importance to prevent further dissemination of AMR in this pathogen. One tool that has shown great promise in combating antibiotic-resistant pathogens is the use of bacteriophages (phages), which are natural bacterial predators and horizontal gene transfer agents. Although native phages can be effective at killing antibiotic-resistant pathogens, limited host ranges and evolved resistance to phages can compromise their use in the efforts to mitigate the global AMR challenge. However, recent advances can allow the use of CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) to selectively target pathogens and their AMR determinants. Employment of CRISPR-Cas systems for phage amendment can overcome previous limitations in using phages as biocontrol and allow for the effective control of L. monocytogenes and its AMR determinants.
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41
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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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42
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Wang L, Zhou J, Wang Q, Wang Y, Kang C. Rapid design and development of CRISPR-Cas13a targeting SARS-CoV-2 spike protein. Theranostics 2021; 11:649-664. [PMID: 33391497 PMCID: PMC7738867 DOI: 10.7150/thno.51479] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022] Open
Abstract
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide epidemic of the lethal respiratory coronavirus disease (COVID-19), necessitating urgent development of specific and effective therapeutic tools. Among several therapeutic targets of coronaviruses, the spike protein is of great significance due to its key role in host invasion. Here, we report a potential anti-SARS-CoV-2 strategy based on the CRISPR-Cas13a system. Methods: A comprehensive set of bioinformatics methods, including sequence alignment, structural comparison, and molecular docking, was utilized to identify a SARS-CoV-2-spike(S)-specific segment. A tiling crRNA library targeting this specific RNA segment was designed, and optimal crRNA candidates were selected using in-silico methods. The efficiencies of the crRNA candidates were tested in human HepG2 and AT2 cells. Results: The most effective crRNA sequence inducing a robust cleavage effect on S and a potent collateral cleavage effect were identified. Conclusions: This study provides a rapid design pipeline for a CRISPR-Cas13a-based antiviral tool against SARS-CoV-2. Moreover, it offers a novel approach for anti-virus study even if the precise structures of viral proteins are indeterminate.
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Affiliation(s)
- Lin Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin 300052, China
| | - Junhu Zhou
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin 300052, China
| | - Qixue Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin 300052, China
| | - Yunfei Wang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin 300052, China
| | - Chunsheng Kang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China
- Tianjin Neurological Institute, Key Laboratory of Post-neurotrauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin 300052, China
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43
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Abstract
Prokaryotes have developed numerous defense strategies to combat the constant threat posed by the diverse genetic parasites that endanger them. Clustered regularly interspaced short palindromic repeat (CRISPR)-Cas loci guard their hosts with an adaptive immune system against foreign nucleic acids. Protection starts with an immunization phase, in which short pieces of the invader's genome, known as spacers, are captured and integrated into the CRISPR locus after infection. Next, during the targeting phase, spacers are transcribed into CRISPR RNAs (crRNAs) that guide CRISPR-associated (Cas) nucleases to destroy the invader's DNA or RNA. Here we describe the many different molecular mechanisms of CRISPR targeting and how they are interconnected with the immunization phase through a third phase of the CRISPR-Cas immune response: primed spacer acquisition. In this phase, Cas proteins direct the crRNA-guided acquisition of additional spacers to achieve a more rapid and robust immunization of the population.
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Affiliation(s)
- Philip M. Nussenzweig
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065, USA
| | - Luciano A. Marraffini
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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44
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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: 25] [Impact Index Per Article: 6.3] [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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45
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Tng PYL, Carabajal Paladino L, Verkuijl SAN, Purcell J, Merits A, Leftwich PT, Fragkoudis R, Noad R, Alphey L. Cas13b-dependent and Cas13b-independent RNA knockdown of viral sequences in mosquito cells following guide RNA expression. Commun Biol 2020; 3:413. [PMID: 32737398 PMCID: PMC7395101 DOI: 10.1038/s42003-020-01142-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 07/09/2020] [Indexed: 12/26/2022] Open
Abstract
Aedes aegypti and Aedes albopictus mosquitoes are vectors of the RNA viruses chikungunya (CHIKV) and dengue that currently have no specific therapeutic treatments. The development of new methods to generate virus-refractory mosquitoes would be beneficial. Cas13b is an enzyme that uses RNA guides to target and cleave RNA molecules and has been reported to suppress RNA viruses in mammalian and plant cells. We investigated the potential use of the Prevotella sp. P5-125 Cas13b system to provide viral refractoriness in mosquito cells, using a virus-derived reporter and a CHIKV split replication system. Cas13b in combination with suitable guide RNAs could induce strong suppression of virus-derived reporter RNAs in insect cells. Surprisingly, the RNA guides alone (without Cas13b) also gave substantial suppression. Our study provides support for the potential use of Cas13b in mosquitoes, but also caution in interpreting CRISPR/Cas data as we show that guide RNAs can have Cas-independent effects.
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Affiliation(s)
- Priscilla Ying Lei Tng
- Arthropod Genetics, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK
- Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire, AL9 7TA, UK
| | | | - Sebald Alexander Nkosana Verkuijl
- Arthropod Genetics, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Jessica Purcell
- Arthropod Genetics, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Andres Merits
- Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
| | - Philip Thomas Leftwich
- Arthropod Genetics, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Rennos Fragkoudis
- Arbovirus Pathogenesis, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK
- The University of Nottingham, School of Veterinary Medicine and Science, Sutton Bonington, Loughborough, LE12 5RD, UK
| | - Rob Noad
- Pathobiology and Population Sciences, The Royal Veterinary College, Hawkshead Lane, Hertfordshire, AL9 7TA, UK
| | - Luke Alphey
- Arthropod Genetics, The Pirbright Institute, Ash Road, Pirbright, GU24 0NF, UK.
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46
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Meeske AJ, Jia N, Cassel AK, Kozlova A, Liao J, Wiedmann M, Patel DJ, Marraffini LA. A phage-encoded anti-CRISPR enables complete evasion of type VI-A CRISPR-Cas immunity. Science 2020; 369:54-59. [PMID: 32467331 PMCID: PMC7975689 DOI: 10.1126/science.abb6151] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/15/2020] [Indexed: 12/11/2022]
Abstract
The CRISPR RNA (crRNA)-guided nuclease Cas13 recognizes complementary viral transcripts to trigger the degradation of both host and viral RNA during the type VI CRISPR-Cas antiviral response. However, how viruses can counteract this immunity is not known. We describe a listeriaphage (ϕLS46) encoding an anti-CRISPR protein (AcrVIA1) that inactivates the type VI-A CRISPR system of Listeria seeligeri Using genetics, biochemistry, and structural biology, we found that AcrVIA1 interacts with the guide-exposed face of Cas13a, preventing access to the target RNA and the conformational changes required for nuclease activation. Unlike inhibitors of DNA-cleaving Cas nucleases, which cause limited immunosuppression and require multiple infections to bypass CRISPR defenses, a single dose of AcrVIA1 delivered by an individual virion completely dismantles type VI-A CRISPR-mediated immunity.
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Affiliation(s)
- Alexander J Meeske
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA
| | - Ning Jia
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Alice K Cassel
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA
| | - Albina Kozlova
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA
| | - Jingqiu Liao
- Department of Food Science, Cornell University, Ithaca, NY 14583, USA
- Graduate Field of Microbiology, Cornell University, Ithaca, NY 14583, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14583, USA
- Graduate Field of Microbiology, Cornell University, Ithaca, NY 14583, USA
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA.
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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47
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Wessels HH, Méndez-Mancilla A, Guo X, Legut M, Daniloski Z, Sanjana NE. Massively parallel Cas13 screens reveal principles for guide RNA design. Nat Biotechnol 2020; 38:722-727. [PMID: 32518401 PMCID: PMC7294996 DOI: 10.1038/s41587-020-0456-9] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 02/11/2020] [Indexed: 12/15/2022]
Abstract
Type VI CRISPR enzymes are RNA-targeting proteins with nuclease activity that enable specific and robust target gene knockdown without altering the genome. To define rules for the design of Cas13d guide RNAs (gRNAs), we conducted massively parallel screens targeting messenger RNAs (mRNAs) of a green fluorescent protein transgene, and CD46, CD55 and CD71 cell-surface proteins in human cells. In total, we measured the activity of 24,460 gRNAs with and without mismatches relative to the target sequences. Knockdown efficacy is driven by gRNA-specific features and target site context. Single mismatches generally reduce knockdown to a modest degree, but spacer nucleotides 15-21 are largely intolerant of target site mismatches. We developed a computational model to identify optimal gRNAs and confirm their generalizability, testing 3,979 guides targeting mRNAs of 48 endogenous genes. We show that Cas13 can be used in forward transcriptomic pooled screens and, using our model, predict optimized Cas13 gRNAs for all protein-coding transcripts in the human genome.
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Affiliation(s)
- Hans-Hermann Wessels
- New York Genome Center, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Alejandro Méndez-Mancilla
- New York Genome Center, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Xinyi Guo
- New York Genome Center, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Mateusz Legut
- New York Genome Center, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Zharko Daniloski
- New York Genome Center, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Neville E Sanjana
- New York Genome Center, New York, NY, USA.
- Department of Biology, New York University, New York, NY, USA.
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48
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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: 76] [Impact Index Per Article: 19.0] [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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49
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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: 49] [Impact Index Per Article: 12.3] [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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50
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Mendoza SD, Nieweglowska ES, Govindarajan S, Leon LM, Berry JD, Tiwari A, Chaikeeratisak V, Pogliano J, Agard DA, Bondy-Denomy J. A bacteriophage nucleus-like compartment shields DNA from CRISPR nucleases. Nature 2019; 577:244-248. [PMID: 31819262 PMCID: PMC6949375 DOI: 10.1038/s41586-019-1786-y] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/11/2019] [Indexed: 11/09/2022]
Abstract
All viruses require strategies to inhibit or evade the immunity pathways of cells they infect. The viruses that infect bacteria, bacteriophages (phages), must avoid nucleic-acid targeting immune pathways such as CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated genes) and restriction-modification (R-M) systems to replicate efficiently1. Here, we show that jumbo phage ΦKZ, infecting Pseudomonas aeruginosa, segregates its DNA from immunity nucleases by constructing a proteinaceous nucleus-like compartment. ΦKZ resists many DNA-targeting immune systems in vivo, including two CRISPR-Cas3 subtypes, Cas9, Cas12a, and the restriction enzymes HsdRMS and EcoRI. Cas and restriction enzymes are unable to access the phage DNA throughout the infection, but engineered re-localization of EcoRI inside the compartment enables phage targeting and cell protection. Moreover, ΦKZ is sensitive to the RNA targeting CRISPR-Cas enzyme, Cas13a, likely due to phage mRNA localizing to the cytoplasm. Collectively, we propose that Pseudomonas jumbo phages evade a broad spectrum of DNA-targeting nucleases through the assembly of a protein barrier around their genome.
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Affiliation(s)
- Senén D Mendoza
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Eliza S Nieweglowska
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Sutharsan Govindarajan
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA.,Department of Biology, SRM University AP, Amaravati, India
| | - Lina M Leon
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Joel D Berry
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Anika Tiwari
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA
| | - Vorrapon Chaikeeratisak
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.,Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - David A Agard
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA.,Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA, USA
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA, USA. .,Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA, USA.
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