1
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Zhang D, Du L, Gao H, Yuan C, Lin Z. Structural insight into the Csx1-Crn2 fusion self-limiting ribonuclease of type III CRISPR system. Nucleic Acids Res 2024; 52:8419-8430. [PMID: 38967023 PMCID: PMC11317161 DOI: 10.1093/nar/gkae569] [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: 04/02/2024] [Revised: 06/14/2024] [Accepted: 06/25/2024] [Indexed: 07/06/2024] Open
Abstract
In the type III CRISPR system, cyclic oligoadenylate (cOA) molecules act as second messengers, activating various promiscuous ancillary nucleases that indiscriminately degrade host and viral DNA/RNA. Conversely, ring nucleases, by specifically cleaving cOA molecules, function as off-switches to protect host cells from dormancy or death, and allow viruses to counteract immune responses. The fusion protein Csx1-Crn2, combining host ribonuclease with viral ring nuclease, represents a unique self-limiting ribonuclease family. Here, we describe the structures of Csx1-Crn2 from the organism of Marinitoga sp., in both its full-length and truncated forms, as well as in complex with cA4. We show that Csx1-Crn2 operates as a homo-tetramer, a configuration crucial for preserving the structural integrity of the HEPN domain and ensuring effective ssRNA cleavage. The binding of cA4 to the CARF domain triggers significant conformational changes across the CARF, HTH, and into the HEPN domains, leading the two R-X4-6-H motifs to form a composite catalytic site. Intriguingly, an acetate ion was found to bind at this composite site by mimicking the scissile phosphate. Further molecular docking analysis reveals that the HEPN domain can accommodate a single ssRNA molecule involving both R-X4-6-H motifs, underscoring the importance of HEPN domain dimerization for its activation.
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Affiliation(s)
- Danping Zhang
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Liyang Du
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Haishan Gao
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Cai Yuan
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, China
| | - Zhonghui Lin
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
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2
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Hoikkala V, Graham S, White MF. Bioinformatic analysis of type III CRISPR systems reveals key properties and new effector families. Nucleic Acids Res 2024; 52:7129-7141. [PMID: 38808661 PMCID: PMC11229360 DOI: 10.1093/nar/gkae462] [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: 03/25/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 05/30/2024] Open
Abstract
Recognition of RNA from invading mobile genetic elements (MGE) prompts type III CRISPR systems to activate an HD nuclease domain and/or a nucleotide cyclase domain in the Cas10 subunit, eliciting an immune response. The cyclase domain can generate a range of nucleotide second messengers, which in turn activate a diverse family of ancillary effector proteins. These provide immunity by non-specific degradation of host and MGE nucleic acids or proteins, perturbation of membrane potentials, transcriptional responses, or the arrest of translation. The wide range of nucleotide activators and downstream effectors generates a complex picture that is gradually being resolved. Here, we carry out a global bioinformatic analysis of type III CRISPR loci in prokaryotic genomes, defining the relationships of Cas10 proteins and their ancillary effectors. Our study reveals that cyclic tetra-adenylate is by far the most common signalling molecule used and that many loci have multiple effectors. These typically share the same activator and may work synergistically to combat MGE. We propose four new candidate effector protein families and confirm experimentally that the Csm6-2 protein, a highly diverged, fused Csm6 effector, is a ribonuclease activated by cyclic hexa-adenylate.
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Affiliation(s)
- Ville Hoikkala
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Shirley Graham
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Malcolm F White
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
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3
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Fuentenebro Navas D, Steens JA, de Lannoy C, Noordijk B, Pfeffer M, de Ridder D, H.J. Staals R, Schmid S. Nanopores Reveal the Stoichiometry of Single Oligoadenylates Produced by Type III CRISPR-Cas. ACS NANO 2024; 18:16505-16515. [PMID: 38875527 PMCID: PMC11223493 DOI: 10.1021/acsnano.3c11769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/27/2024] [Accepted: 06/05/2024] [Indexed: 06/16/2024]
Abstract
Cyclic oligoadenylates (cOAs) are small second messenger molecules produced by the type III CRISPR-Cas system as part of the prokaryotic immune response. The role of cOAs is to allosterically activate downstream effector proteins that induce dormancy or cell death, and thus abort viral spread through the population. Interestingly, different type III systems have been reported to utilize different cOA stoichiometries (with 3 to 6 adenylate monophosphates). However, so far, their characterization has only been possible in bulk and with sophisticated equipment, while a portable assay with single-molecule resolution has been lacking. Here, we demonstrate the label-free detection of single cOA molecules using a simple protein nanopore assay. It sensitively identifies the stoichiometry of individual cOA molecules and their mixtures from synthetic and enzymatic origin. To achieve this, we trained a convolutional neural network (CNN) and validated it with a series of experiments on mono- and polydisperse cOA samples. Ultimately, we determined the stoichiometric composition of cOAs produced enzymatically by the CRISPR type III-A and III-B variants of Thermus thermophilus and confirmed the results by liquid chromatography-mass spectroscopy (LC-MS). Interestingly, both variants produce cOAs of nearly identical composition (within experimental uncertainties), and we discuss the biological implications of this finding. The presented nanopore-CNN workflow with single cOA resolution can be adapted to many other signaling molecules (including eukaryotic ones), and it may be integrated into portable handheld devices with potential point-of-care applications.
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Affiliation(s)
- David Fuentenebro Navas
- Laboratory
of Biophysics, Wageningen University and
Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Jurre A. Steens
- Laboratory
of Microbiology, Wageningen University and
Research, Stippeneng
4, 6708WE Wageningen, The Netherlands
| | - Carlos de Lannoy
- Bioinformatics
Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
- Department
of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Ben Noordijk
- Bioinformatics
Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Michael Pfeffer
- Department
of Chemistry, University of Basel, Mattenstrasse 22, 4058 Basel, Switzerland
| | - Dick de Ridder
- Bioinformatics
Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Raymond H.J. Staals
- Laboratory
of Microbiology, Wageningen University and
Research, Stippeneng
4, 6708WE Wageningen, The Netherlands
| | - Sonja Schmid
- Laboratory
of Biophysics, Wageningen University and
Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
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4
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Bell RT, Sahakyan H, Makarova KS, Wolf YI, Koonin EV. CoCoNuTs are a diverse subclass of Type IV restriction systems predicted to target RNA. eLife 2024; 13:RP94800. [PMID: 38739430 PMCID: PMC11090510 DOI: 10.7554/elife.94800] [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] [Indexed: 05/14/2024] Open
Abstract
A comprehensive census of McrBC systems, among the most common forms of prokaryotic Type IV restriction systems, followed by phylogenetic analysis, reveals their enormous abundance in diverse prokaryotes and a plethora of genomic associations. We focus on a previously uncharacterized branch, which we denote coiled-coil nuclease tandems (CoCoNuTs) for their salient features: the presence of extensive coiled-coil structures and tandem nucleases. The CoCoNuTs alone show extraordinary variety, with three distinct types and multiple subtypes. All CoCoNuTs contain domains predicted to interact with translation system components, such as OB-folds resembling the SmpB protein that binds bacterial transfer-messenger RNA (tmRNA), YTH-like domains that might recognize methylated tmRNA, tRNA, or rRNA, and RNA-binding Hsp70 chaperone homologs, along with RNases, such as HEPN domains, all suggesting that the CoCoNuTs target RNA. Many CoCoNuTs might additionally target DNA, via McrC nuclease homologs. Additional restriction systems, such as Type I RM, BREX, and Druantia Type III, are frequently encoded in the same predicted superoperons. In many of these superoperons, CoCoNuTs are likely regulated by cyclic nucleotides, possibly, RNA fragments with cyclic termini, that bind associated CARF (CRISPR-Associated Rossmann Fold) domains. We hypothesize that the CoCoNuTs, together with the ancillary restriction factors, employ an echeloned defense strategy analogous to that of Type III CRISPR-Cas systems, in which an immune response eliminating virus DNA and/or RNA is launched first, but then, if it fails, an abortive infection response leading to PCD/dormancy via host RNA cleavage takes over.
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Affiliation(s)
- Ryan T Bell
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Harutyun Sahakyan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaUnited States
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5
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Schwartz EA, Bravo JPK, Ahsan M, Macias LA, McCafferty CL, Dangerfield TL, Walker JN, Brodbelt JS, Palermo G, Fineran PC, Fagerlund RD, Taylor DW. RNA targeting and cleavage by the type III-Dv CRISPR effector complex. Nat Commun 2024; 15:3324. [PMID: 38637512 PMCID: PMC11026444 DOI: 10.1038/s41467-024-47506-y] [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: 08/21/2023] [Accepted: 04/02/2024] [Indexed: 04/20/2024] Open
Abstract
CRISPR-Cas are adaptive immune systems in bacteria and archaea that utilize CRISPR RNA-guided surveillance complexes to target complementary RNA or DNA for destruction1-5. Target RNA cleavage at regular intervals is characteristic of type III effector complexes6-8. Here, we determine the structures of the Synechocystis type III-Dv complex, an apparent evolutionary intermediate from multi-protein to single-protein type III effectors9,10, in pre- and post-cleavage states. The structures show how multi-subunit fusion proteins in the effector are tethered together in an unusual arrangement to assemble into an active and programmable RNA endonuclease and how the effector utilizes a distinct mechanism for target RNA seeding from other type III effectors. Using structural, biochemical, and quantum/classical molecular dynamics simulation, we study the structure and dynamics of the three catalytic sites, where a 2'-OH of the ribose on the target RNA acts as a nucleophile for in line self-cleavage of the upstream scissile phosphate. Strikingly, the arrangement at the catalytic residues of most type III complexes resembles the active site of ribozymes, including the hammerhead, pistol, and Varkud satellite ribozymes. Our work provides detailed molecular insight into the mechanisms of RNA targeting and cleavage by an important intermediate in the evolution of type III effector complexes.
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Affiliation(s)
- Evan A Schwartz
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX, USA
| | - Jack P K Bravo
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Mohd Ahsan
- Department of Bioengineering and Department of Chemistry, University of California, Riverside, CA, USA
| | - Luis A Macias
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | - Caitlyn L McCafferty
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX, USA
| | - Tyler L Dangerfield
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Jada N Walker
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | | | - Giulia Palermo
- Department of Bioengineering and Department of Chemistry, University of California, Riverside, CA, USA.
| | - Peter C Fineran
- Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin, New Zealand
- Genetics Otago, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Robert D Fagerlund
- Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, New Zealand.
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin, New Zealand.
- Genetics Otago, University of Otago, PO Box 56, Dunedin, New Zealand.
| | - David W Taylor
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX, USA.
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA.
- Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, USA.
- LIVESTRONG Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX, USA.
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6
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Grüschow S, McQuarrie S, Ackermann K, McMahon S, Bode B, Gloster T, White M. CRISPR antiphage defence mediated by the cyclic nucleotide-binding membrane protein Csx23. Nucleic Acids Res 2024; 52:2761-2775. [PMID: 38471818 PMCID: PMC11014256 DOI: 10.1093/nar/gkae167] [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: 12/01/2023] [Revised: 02/21/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
CRISPR-Cas provides adaptive immunity in prokaryotes. Type III CRISPR systems detect invading RNA and activate the catalytic Cas10 subunit, which generates a range of nucleotide second messengers to signal infection. These molecules bind and activate a diverse range of effector proteins that provide immunity by degrading viral components and/or by disturbing key aspects of cellular metabolism to slow down viral replication. Here, we focus on the uncharacterised effector Csx23, which is widespread in Vibrio cholerae. Csx23 provides immunity against plasmids and phage when expressed in Escherichia coli along with its cognate type III CRISPR system. The Csx23 protein localises in the membrane using an N-terminal transmembrane α-helical domain and has a cytoplasmic C-terminal domain that binds cyclic tetra-adenylate (cA4), activating its defence function. Structural studies reveal a tetrameric structure with a novel fold that binds cA4 specifically. Using pulse EPR, we demonstrate that cA4 binding to the cytoplasmic domain of Csx23 results in a major perturbation of the transmembrane domain, consistent with the opening of a pore and/or disruption of membrane integrity. This work reveals a new class of cyclic nucleotide binding protein and provides key mechanistic detail on a membrane-associated CRISPR effector.
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Affiliation(s)
- Sabine Grüschow
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Stuart McQuarrie
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Katrin Ackermann
- Biomedical Sciences Research Complex, School of Chemistry, Centre of Magnetic Resonance, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Stephen McMahon
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Bela E Bode
- Biomedical Sciences Research Complex, School of Chemistry, Centre of Magnetic Resonance, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, Fife KY16 9ST, UK
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7
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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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8
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Li X, Han J, Yang J, Zhang H. The structural biology of type III CRISPR-Cas systems. J Struct Biol 2024; 216:108070. [PMID: 38395113 DOI: 10.1016/j.jsb.2024.108070] [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: 10/27/2023] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
CRISPR-Cas system is an RNA-guided adaptive immune system widespread in bacteria and archaea. Among them, type III CRISPR-Cas systems are the most ancient throughout the CRISPR-Cas family, proving anti-phage defense through a crRNA-guided RNA targeting manner and possessing multiple enzymatic activities. Type III CRISPR-Cas systems comprise four typical members (type III-A to III-D) and two atypical members (type III-E and type III-F), providing immune defense through distinct mechanisms. Here, we delve into structural studies conducted on three well-characterized members: the type III-A, III-B, and III-E systems, provide an overview of the structural insights into the crRNA-guided target RNA cleavage, self/non-self discrimination, and the target RNA-dependent regulation of enzymatic subunits in the effector complex.
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Affiliation(s)
- Xuzichao Li
- State Key Laboratory of Experimental Hematology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Jie Han
- Department of Anatomy and Histology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Jie Yang
- State Key Laboratory of Experimental Hematology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Heng Zhang
- State Key Laboratory of Experimental Hematology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China.
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9
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Aviram N, Shilton AK, Lyn NG, Reis BS, Brivanlou A, Marraffini LA. The Cas10 nuclease activity relieves host dormancy to facilitate spacer acquisition and retention during type III-A CRISPR immunity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.11.579731. [PMID: 38405743 PMCID: PMC10888962 DOI: 10.1101/2024.02.11.579731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A hallmark of CRISPR immunity is the acquisition of short viral DNA sequences, known as spacers, that are transcribed into guide RNAs to recognize complementary sequences. The staphylococcal type III-A CRISPR-Cas system uses guide RNAs to locate viral transcripts and start a response that displays two mechanisms of immunity. When immunity is triggered by an early-expressed phage RNA, degradation of viral ssDNA can cure the host from infection. In contrast, when the RNA guide targets a late-expressed transcript, defense requires the activity of Csm6, a non-specific RNase. Here we show that Csm6 triggers a growth arrest of the host that provides immunity at the population level which hinders viral propagation to allow the replication of non-infected cells. We demonstrate that this mechanism leads to defense against not only the target phage but also other viruses present in the population that fail to replicate in the arrested cells. On the other hand, dormancy limits the acquisition and retention of spacers that trigger it. We found that the ssDNase activity of type III-A systems is required for the re-growth of a subset of the arrested cells, presumably through the degradation of the phage DNA, ending target transcription and inactivating the immune response. Altogether, our work reveals a built-in mechanism within type III-A CRISPR-Cas systems that allows the exit from dormancy needed for the subsistence of spacers that provide broad-spectrum immunity.
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Affiliation(s)
- Naama Aviram
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Amanda K Shilton
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Nia G Lyn
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Bernardo S Reis
- Laboratory of Mucosal Immunology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Amir Brivanlou
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Luciano A Marraffini
- Laboratory of Bacteriology, the Rockefeller University, 1230 York Ave, New York, NY 10065, USA
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
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10
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Bell RT, Sahakyan H, Makarova KS, Wolf YI, Koonin EV. CoCoNuTs: A diverse subclass of Type IV restriction systems predicted to target RNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.31.551357. [PMID: 37790407 PMCID: PMC10542128 DOI: 10.1101/2023.07.31.551357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
A comprehensive census of McrBC systems, among the most common forms of prokaryotic Type IV restriction systems, followed by phylogenetic analysis, reveals their enormous abundance in diverse prokaryotes and a plethora of genomic associations. We focus on a previously uncharacterized branch, which we denote CoCoNuTs (coiled-coil nuclease tandems) for their salient features: the presence of extensive coiled-coil structures and tandem nucleases. The CoCoNuTs alone show extraordinary variety, with 3 distinct types and multiple subtypes. All CoCoNuTs contain domains predicted to interact with translation system components, such as OB-folds resembling the SmpB protein that binds bacterial transfer-messenger RNA (tmRNA), YTH-like domains that might recognize methylated tmRNA, tRNA, or rRNA, and RNA-binding Hsp70 chaperone homologs, along with RNases, such as HEPN domains, all suggesting that the CoCoNuTs target RNA. Many CoCoNuTs might additionally target DNA, via McrC nuclease homologs. Additional restriction systems, such as Type I RM, BREX, and Druantia Type III, are frequently encoded in the same predicted superoperons. In many of these superoperons, CoCoNuTs are likely regulated by cyclic nucleotides, possibly, RNA fragments with cyclic termini, that bind associated CARF (CRISPR-Associated Rossmann Fold) domains. We hypothesize that the CoCoNuTs, together with the ancillary restriction factors, employ an echeloned defense strategy analogous to that of Type III CRISPR-Cas systems, in which an immune response eliminating virus DNA and/or RNA is launched first, but then, if it fails, an abortive infection response leading to PCD/dormancy via host RNA cleavage takes over.
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Affiliation(s)
- Ryan T. Bell
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Harutyun Sahakyan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Yuri I. Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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11
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Steens JA, Bravo JP, Salazar CRP, Yildiz C, Amieiro AM, Köstlbacher S, Prinsen SH, Andres AS, Patinios C, Bardis A, Barendregt A, Scheltema RA, Ettema TJ, van der Oost J, Taylor DW, Staals RH. Type III-B CRISPR-Cas cascade of proteolytic cleavages. Science 2024; 383:512-519. [PMID: 38301007 PMCID: PMC11220425 DOI: 10.1126/science.adk0378] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 12/20/2023] [Indexed: 02/03/2024]
Abstract
The generation of cyclic oligoadenylates and subsequent allosteric activation of proteins that carry sensory domains is a distinctive feature of type III CRISPR-Cas systems. In this work, we characterize a set of associated genes of a type III-B system from Haliangium ochraceum that contains two caspase-like proteases, SAVED-CHAT and PCaspase (prokaryotic caspase), co-opted from a cyclic oligonucleotide-based antiphage signaling system (CBASS). Cyclic tri-adenosine monophosphate (AMP)-induced oligomerization of SAVED-CHAT activates proteolytic activity of the CHAT domains, which specifically cleave and activate PCaspase. Subsequently, activated PCaspase cleaves a multitude of proteins, which results in a strong interference phenotype in vivo in Escherichia coli. Taken together, our findings reveal how a CRISPR-Cas-based detection of a target RNA triggers a cascade of caspase-associated proteolytic activities.
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Affiliation(s)
- Jurre A. Steens
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
- Scope Biosciences B.V.; Wageningen, The Netherlands
| | - Jack P.K. Bravo
- Department of Molecular Biosciences, University of Texas at Austin; Austin, USA
| | | | - Caglar Yildiz
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - Afonso M. Amieiro
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - Stephan Köstlbacher
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | | | - Ane S. Andres
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - Constantinos Patinios
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - Andreas Bardis
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - Arjan Barendregt
- Biomolecular Mass Spectrometry and Proteomics, University of Utrecht; Utrecht, The Netherlands
| | - Richard A. Scheltema
- Biomolecular Mass Spectrometry and Proteomics, University of Utrecht; Utrecht, The Netherlands
| | - Thijs J.G. Ettema
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
| | - David W. Taylor
- Department of Molecular Biosciences, University of Texas at Austin; Austin, USA
| | - Raymond H.J. Staals
- Laboratory of Microbiology, Wageningen University and Research; Wageningen, The Netherlands
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12
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Jungfer K, Sigg A, Jinek M. Substrate selectivity and catalytic activation of the type III CRISPR ancillary nuclease Can2. Nucleic Acids Res 2024; 52:462-473. [PMID: 38033326 PMCID: PMC10783487 DOI: 10.1093/nar/gkad1102] [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: 07/26/2023] [Revised: 10/26/2023] [Accepted: 11/09/2023] [Indexed: 12/02/2023] Open
Abstract
Type III CRISPR-Cas systems provide adaptive immunity against foreign mobile genetic elements through RNA-guided interference. Sequence-specific recognition of RNA targets by the type III effector complex triggers the generation of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins, thus reinforcing the host immune response. The ancillary nuclease Can2 is activated by cyclic tetra-AMP (cA4); however, the mechanisms underlying cA4-mediated activation and substrate selectivity remain elusive. Here we report crystal structures of Thermoanaerobacter brockii Can2 (TbrCan2) in substrate- and product-bound complexes. We show that TbrCan2 is a single strand-selective DNase and RNase that binds substrates via a conserved SxTTS active site motif, and reveal molecular interactions underpinning its sequence preference for CA dinucleotides. Furthermore, we identify a molecular interaction relay linking the cA4 binding site and the nuclease catalytic site to enable divalent metal cation coordination and catalytic activation. These findings provide key insights into the molecular mechanisms of Can2 nucleases in type III CRISPR-Cas immunity and may guide their technological development for nucleic acid detection applications.
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Affiliation(s)
- Kenny Jungfer
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Annina Sigg
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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13
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Stella G, Marraffini L. Type III CRISPR-Cas: beyond the Cas10 effector complex. Trends Biochem Sci 2024; 49:28-37. [PMID: 37949766 PMCID: PMC10844953 DOI: 10.1016/j.tibs.2023.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/13/2023] [Indexed: 11/12/2023]
Abstract
Type III CRISPR-Cas loci encode some of the most abundant, yet complex, immune systems of prokaryotes. They are composed of a Cas10 complex that uses an RNA guide to recognize transcripts from bacteriophage and plasmid invaders. Target recognition triggers three activities within this complex: ssDNA degradation, synthesis of cyclic oligoadenylates (cOA) that act as second messengers to activate CARF-domain effectors, and cleavage of target RNA. This review covers recent research in type III CRISPR-Cas systems that looked beyond the activity of the canonical Cas10 complexes towards: (i) ancillary nucleases and understanding how they provide defense by sensing cOA molecules; (ii) ring nucleases and their role in regulating cOA production; and (iii) CRISPR-associated proteases, including the function of the Craspase complex in a transcriptional response to phage infection.
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Affiliation(s)
- Gianna Stella
- Laboratory of Bacteriology, The Rockefeller University, New York, NY 10065, USA; Tri-Institutional PhD Program in Chemical Biology, Weill Cornell Medical College, Rockefeller University and Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| | - Luciano 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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14
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Du L, Zhu Q, Lin Z. Molecular mechanism of allosteric activation of the CRISPR ribonuclease Csm6 by cyclic tetra-adenylate. EMBO J 2024; 43:304-315. [PMID: 38177499 PMCID: PMC10897365 DOI: 10.1038/s44318-023-00017-w] [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: 08/03/2023] [Revised: 11/16/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024] Open
Abstract
Type III CRISPR systems are innate immune systems found in bacteria and archaea, which produce cyclic oligoadenylate (cOA) second messengers in response to viral infections. In these systems, Csm6 proteins serve as ancillary nucleases that degrade single-stranded RNA (ssRNA) upon activation by cOA. In addition, Csm6 proteins also possess cOA-degrading activity as an intrinsic off-switch to avoid degradation of host RNA and DNA that would eventually lead to cell dormancy or cell death. Here, we present the crystal structures of Thermus thermophilus (Tt) Csm6 alone, and in complex with cyclic tetra-adenylate (cA4) in both pre- and post-cleavage states. These structures establish the molecular basis of the long-range allosteric activation of TtCsm6 ribonuclease by cA4. cA4 binding induces significant conformational changes, including closure of the CARF domain, dimerization of the HTH domain, and reorganization of the R-X4-6-H motif within the HEPN domain. The cleavage of cA4 by the CARF domain restores each domain to a conformation similar to its apo state. Furthermore, we have identified hyperactive TtCsm6 variants that exhibit sustained cA4-activated RNase activity, showing great promise for their applications in genome editing and diagnostics.
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Affiliation(s)
- Liyang Du
- College of Chemistry, Fuzhou University, 350108, Fuzhou, China
| | - Qinwei Zhu
- College of Chemistry, Fuzhou University, 350108, Fuzhou, China
| | - Zhonghui Lin
- College of Chemistry, Fuzhou University, 350108, Fuzhou, China.
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15
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Mogila I, Tamulaitiene G, Keda K, Timinskas A, Ruksenaite A, Sasnauskas G, Venclovas Č, Siksnys V, Tamulaitis G. Ribosomal stalk-captured CARF-RelE ribonuclease inhibits translation following CRISPR signaling. Science 2023; 382:1036-1041. [PMID: 38033086 DOI: 10.1126/science.adj2107] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/31/2023] [Indexed: 12/02/2023]
Abstract
Prokaryotic type III CRISPR-Cas antiviral systems employ cyclic oligoadenylate (cAn) signaling to activate a diverse range of auxiliary proteins that reinforce the CRISPR-Cas defense. Here we characterize a class of cAn-dependent effector proteins named CRISPR-Cas-associated messenger RNA (mRNA) interferase 1 (Cami1) consisting of a CRISPR-associated Rossmann fold sensor domain fused to winged helix-turn-helix and a RelE-family mRNA interferase domain. Upon activation by cyclic tetra-adenylate (cA4), Cami1 cleaves mRNA exposed at the ribosomal A-site thereby depleting mRNA and leading to cell growth arrest. The structures of apo-Cami1 and the ribosome-bound Cami1-cA4 complex delineate the conformational changes that lead to Cami1 activation and the mechanism of Cami1 binding to a bacterial ribosome, revealing unexpected parallels with eukaryotic ribosome-inactivating proteins.
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Affiliation(s)
- Irmantas Mogila
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Giedre Tamulaitiene
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Konstanty Keda
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Albertas Timinskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Audrone Ruksenaite
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Giedrius Sasnauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Česlovas Venclovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Gintautas Tamulaitis
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
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16
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Shuman S. RNA Repair: Hiding in Plain Sight. Annu Rev Genet 2023; 57:461-489. [PMID: 37722686 DOI: 10.1146/annurev-genet-071719-021856] [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] [Indexed: 09/20/2023]
Abstract
Enzymes that phosphorylate, dephosphorylate, and ligate RNA 5' and 3' ends were discovered more than half a century ago and were eventually shown to repair purposeful site-specific endonucleolytic breaks in the RNA phosphodiester backbone. The pace of discovery and characterization of new candidate RNA repair activities in taxa from all phylogenetic domains greatly exceeds our understanding of the biological pathways in which they act. The key questions anent RNA break repair in vivo are (a) identifying the triggers, agents, and targets of RNA cleavage and (b) determining whether RNA repair results in restoration of the original RNA, modification of the RNA (by loss or gain at the ends), or rearrangements of the broken RNA segments (i.e., RNA recombination). This review provides a perspective on the discovery, mechanisms, and physiology of purposeful RNA break repair, highlighting exemplary repair pathways (e.g., tRNA restriction-repair and tRNA splicing) for which genetics has figured prominently in their elucidation.
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Affiliation(s)
- Stewart Shuman
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA;
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17
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Nicastro GG, Burroughs AM, Iyer L, Aravind L. Functionally comparable but evolutionarily distinct nucleotide-targeting effectors help identify conserved paradigms across diverse immune systems. Nucleic Acids Res 2023; 51:11479-11503. [PMID: 37889040 PMCID: PMC10681802 DOI: 10.1093/nar/gkad879] [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: 07/17/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
While nucleic acid-targeting effectors are known to be central to biological conflicts and anti-selfish element immunity, recent findings have revealed immune effectors that target their building blocks and the cellular energy currency-free nucleotides. Through comparative genomics and sequence-structure analysis, we identified several distinct effector domains, which we named Calcineurin-CE, HD-CE, and PRTase-CE. These domains, along with specific versions of the ParB and MazG domains, are widely present in diverse prokaryotic immune systems and are predicted to degrade nucleotides by targeting phosphate or glycosidic linkages. Our findings unveil multiple potential immune systems associated with at least 17 different functional themes featuring these effectors. Some of these systems sense modified DNA/nucleotides from phages or operate downstream of novel enzymes generating signaling nucleotides. We also uncovered a class of systems utilizing HSP90- and HSP70-related modules as analogs of STAND and GTPase domains that are coupled to these nucleotide-targeting- or proteolysis-induced complex-forming effectors. While widespread in bacteria, only a limited subset of nucleotide-targeting effectors was integrated into eukaryotic immune systems, suggesting barriers to interoperability across subcellular contexts. This work establishes nucleotide-degrading effectors as an emerging immune paradigm and traces their origins back to homologous domains in housekeeping systems.
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Affiliation(s)
- Gianlucca G Nicastro
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - A Maxwell Burroughs
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - Lakshminarayan M Iyer
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - L Aravind
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
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18
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Colognori D, Trinidad M, Doudna JA. Precise transcript targeting by CRISPR-Csm complexes. Nat Biotechnol 2023; 41:1256-1264. [PMID: 36690762 PMCID: PMC10497410 DOI: 10.1038/s41587-022-01649-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/15/2022] [Indexed: 01/24/2023]
Abstract
Robust and precise transcript targeting in mammalian cells remains a difficult challenge using existing approaches due to inefficiency, imprecision and subcellular compartmentalization. Here we show that the clustered regularly interspaced short palindromic repeats (CRISPR)-Csm complex, a multiprotein effector from type III CRISPR immune systems in prokaryotes, provides surgical RNA ablation of both nuclear and cytoplasmic transcripts. As part of the most widely occurring CRISPR adaptive immune pathway, CRISPR-Csm uses a programmable RNA-guided mechanism to find and degrade target RNA molecules without inducing indiscriminate trans-cleavage of cellular RNAs, giving it an important advantage over the CRISPR-Cas13 family of enzymes. Using single-vector delivery of the Streptococcus thermophilus Csm complex, we observe high-efficiency RNA knockdown (90-99%) and minimal off-target effects in human cells, outperforming existing technologies including short hairpin RNA- and Cas13-mediated knockdown. We also find that catalytically inactivated Csm achieves specific and durable RNA binding, a property we harness for live-cell RNA imaging. These results establish the feasibility and efficacy of multiprotein CRISPR-Cas effector complexes as RNA-targeting tools in eukaryotes.
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Affiliation(s)
- David Colognori
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Marena Trinidad
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- Department of Chemistry, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Gladstone Institutes, San Francisco, CA, USA.
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19
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Chen X, Wolin SL. Transfer RNA halves are found as nicked tRNAs in cells: evidence that nicked tRNAs regulate expression of an RNA repair operon. RNA (NEW YORK, N.Y.) 2023; 29:620-629. [PMID: 36781286 PMCID: PMC10159003 DOI: 10.1261/rna.079575.122] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 02/01/2023] [Indexed: 05/06/2023]
Abstract
Transfer RNA fragments are proposed to regulate numerous processes in eukaryotes, including translation inhibition, epigenetic inheritance, and cancer. In the bacterium Salmonella enterica serovar Typhimurium, 5' tRNA halves ending in 2',3' cyclic phosphate are proposed to bind the RtcR transcriptional activator, resulting in transcription of an RNA repair operon. However, since 5' and 3' tRNA halves can remain base paired after cleavage, the 5' tRNA halves could potentially bind RtcR as nicked tRNAs. Here we report that nicked tRNAs are ligands for RtcR. By isolating RNA from bacteria under conditions that preserve base pairing, we show that many tRNA halves are in the form of nicked tRNAs. Using a circularly permuted tRNA that mimics a nicked tRNA, we show that nicked tRNA ending in 2',3' cyclic phosphate is a better ligand for RtcR than the corresponding 5' tRNA half. In human cells, we show that some tRNA halves similarly remain base paired as nicked tRNAs following cleavage by anticodon nucleases. Our work supports a role for the RNA repair operon in repairing nicked tRNAs and has implications for the functions proposed for tRNA fragments in eukaryotes.
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Affiliation(s)
- Xinguo Chen
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Sandra L Wolin
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
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20
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Wiegand T, Wilkinson R, Santiago-Frangos A, Lynes M, Hatzenpichler R, Wiedenheft B. Functional and Phylogenetic Diversity of Cas10 Proteins. CRISPR J 2023; 6:152-162. [PMID: 36912817 PMCID: PMC10123807 DOI: 10.1089/crispr.2022.0085] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/30/2023] [Indexed: 03/14/2023] Open
Abstract
Cas10 proteins are large subunits of type III CRISPR RNA (crRNA)-guided surveillance complexes, many of which have nuclease and cyclase activities. Here, we use computational and phylogenetic methods to identify and analyze 2014 Cas10 sequences from genomic and metagenomic databases. Cas10 proteins cluster into five distinct clades that mirror previously established CRISPR-Cas subtypes. Most Cas10 proteins (85.0%) have conserved polymerase active-site motifs, while HD-nuclease domains are less well conserved (36.0%). We identify Cas10 variants that are split over multiple genes or genetically fused to nucleases activated by cyclic nucleotides (i.e., NucC) or components of toxin-antitoxin systems (i.e., AbiEii). To clarify the functional diversification of Cas10 proteins, we cloned, expressed, and purified five representatives from three phylogenetically distinct clades. None of the Cas10s are functional cyclases in isolation, and activity assays performed with polymerase domain active site mutants indicate that previously reported Cas10 DNA-polymerase activity may be a result of contamination. Collectively, this work helps clarify the phylogenetic and functional diversity of Cas10 proteins in type III CRISPR systems.
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Affiliation(s)
- Tanner Wiegand
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Royce Wilkinson
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Andrew Santiago-Frangos
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Mackenzie Lynes
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Roland Hatzenpichler
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
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21
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Makarova KS, Wolf YI, Koonin EV. In Silico Approaches for Prediction of Anti-CRISPR Proteins. J Mol Biol 2023; 435:168036. [PMID: 36868398 PMCID: PMC10073340 DOI: 10.1016/j.jmb.2023.168036] [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: 10/26/2022] [Revised: 02/18/2023] [Accepted: 02/23/2023] [Indexed: 03/05/2023]
Abstract
Numerous viruses infecting bacteria and archaea encode CRISPR-Cas system inhibitors, known as anti-CRISPR proteins (Acr). The Acrs typically are highly specific for particular CRISPR variants, resulting in remarkable sequence and structural diversity and complicating accurate prediction and identification of Acrs. In addition to their intrinsic interest for understanding the coevolution of defense and counter-defense systems in prokaryotes, Acrs could be natural, potent on-off switches for CRISPR-based biotechnological tools, so their discovery, characterization and application are of major importance. Here we discuss the computational approaches for Acr prediction. Due to the enormous diversity and likely multiple origins of the Acrs, sequence similarity searches are of limited use. However, multiple features of protein and gene organization have been successfully harnessed to this end including small protein size and distinct amino acid compositions of the Acrs, association of acr genes in virus genomes with genes encoding helix-turn-helix proteins that regulate Acr expression (Acr-associated proteins, Aca), and presence of self-targeting CRISPR spacers in bacterial and archaeal genomes containing Acr-encoding proviruses. Productive approaches for Acr prediction also involve genome comparison of closely related viruses, of which one is resistant and the other one is sensitive to a particular CRISPR variant, and "guilt by association" whereby genes adjacent to a homolog of a known Aca are identified as candidate Acrs. The distinctive features of Acrs are employed for Acr prediction both by developing dedicated search algorithms and through machine learning. New approaches will be needed to identify novel types of Acrs that are likely to exist.
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, USA.
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, USA
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22
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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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23
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Du L, Zhang D, Luo Z, Lin Z. Molecular basis of stepwise cyclic tetra-adenylate cleavage by the type III CRISPR ring nuclease Crn1/Sso2081. Nucleic Acids Res 2023; 51:2485-2495. [PMID: 36807980 PMCID: PMC10018336 DOI: 10.1093/nar/gkad101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 02/22/2023] Open
Abstract
The cyclic oligoadenylates (cOAs) act as second messengers of the type III CRISPR immunity system through activating the auxiliary nucleases for indiscriminate RNA degradation. The cOA-degrading nucleases (ring nucleases) provide an 'off-switch' regulation of the signaling, thereby preventing cell dormancy or cell death. Here, we describe the crystal structures of the founding member of CRISPR-associated ring nuclease 1 (Crn1) Sso2081 from Saccharolobus solfataricus, alone, bound to phosphate ions or cA4 in both pre-cleavage and cleavage intermediate states. These structures together with biochemical characterizations establish the molecular basis of cA4 recognition and catalysis by Sso2081. The conformational changes in the C-terminal helical insert upon the binding of phosphate ions or cA4 reveal a gate-locking mechanism for ligand binding. The critical residues and motifs identified in this study provide a new insight to distinguish between cOA-degrading and -nondegrading CARF domain-containing proteins.
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Affiliation(s)
- Liyang Du
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Danping Zhang
- College of Chemistry, Fuzhou University, Fuzhou 350108, China
| | - Zhipu Luo
- Correspondence may also be addressed to Zhipu Luo.
| | - Zhonghui Lin
- To whom correspondence should be addressed. Tel: +86 0591 22867273;
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24
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Specific recognition of cyclic oligonucleotides by Cap4 for phage infection. Int J Biol Macromol 2023; 237:123656. [PMID: 36796558 DOI: 10.1016/j.ijbiomac.2023.123656] [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: 10/28/2022] [Revised: 02/04/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023]
Abstract
Under selective pressure, bacteria have evolved diverse defense systems against phage infections. The SMODS-associated and fused to various effector domains (SAVED)-domain containing proteins were identified as major downstream effectors in cyclic oligonucleotide-based antiphage signaling system (CBASS) for bacterial defense. Recent study structurally characterizes a cGAS/DncV-like nucleotidyltransferase (CD-NTase)-associated protein 4 from Acinetobacter baumannii (AbCap4) in complex with 2'3'3'-cyclic AMP-AMP-AMP (cAAA). However, the homologue Cap4 from Enterobacter cloacae (EcCap4) is activated by 3'3'3'-cyclic AMP-AMP-GMP (cAAG). To elucidate the ligand specificity of Cap4 proteins, we determined the crystal structures of full-length wild-type and K74A mutant of EcCap4 to 2.18 and 2.42 Å resolution, respectively. The DNA endonuclease domain of EcCap4 shares similar catalytic mechanism with type II restriction endonuclease. Mutating the key residue K74 in the conserved DXn(D/E)XK motif completely abolishes its DNA degradation activity. The potential ligand-binding cavity of EcCap4 SAVED domain is located adjacent to its N-terminal domain, significantly differing from the centrally located cavity of AbCap4 SAVED domain which recognizes cAAA. Based on structural and bioinformatic analysis, we found that Cap4 proteins can be classified into two types: the type I Cap4, like AbCap4, recognize cAAA and the type II Cap4, like EcCap4, bind cAAG. Several conserved residues identified at the surface of potential ligand-binding pocket of EcCap4 SAVED domain are confirmed by ITC experiment for their direct binding roles for cAAG. Changing Q351, T391 and R392 to alanine abolished the binding of cAAG by EcCap4 and significantly reduced the anti-phage ability of the E. cloacae CBASS system constituting EcCdnD (CD-NTase in clade D) and EcCap4. In summary, we revealed the molecular basis for specific cAAG recognition by the C-terminal SAVED domain of EcCap4 and demonstrates the structural differences for ligand discrimination among different SAVED-domain containing proteins.
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25
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Rouillon C, Schneberger N, Chi H, Blumenstock K, Da Vela S, Ackermann K, Moecking J, Peter MF, Boenigk W, Seifert R, Bode BE, Schmid-Burgk JL, Svergun D, Geyer M, White MF, Hagelueken G. Antiviral signalling by a cyclic nucleotide activated CRISPR protease. Nature 2023; 614:168-174. [PMID: 36423657 DOI: 10.1038/s41586-022-05571-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 11/17/2022] [Indexed: 11/27/2022]
Abstract
CRISPR defence systems such as the well-known DNA-targeting Cas9 and the RNA-targeting type III systems are widespread in prokaryotes1,2. The latter orchestrates a complex antiviral response that is initiated through the synthesis of cyclic oligoadenylates after recognition of foreign RNA3-5. Among the large set of proteins that are linked to type III systems and predicted to bind cyclic oligoadenylates6,7, a CRISPR-associated Lon protease (CalpL) stood out to us. CalpL contains a sensor domain of the SAVED family7 fused to a Lon protease effector domain. However, the mode of action of this effector is unknown. Here we report the structure and function of CalpL and show that this soluble protein forms a stable tripartite complex with two other proteins, CalpT and CalpS, that are encoded on the same operon. After activation by cyclic tetra-adenylate (cA4), CalpL oligomerizes and specifically cleaves the MazF homologue CalpT, which releases the extracytoplasmic function σ factor CalpS from the complex. Our data provide a direct connection between CRISPR-based detection of foreign nucleic acids and transcriptional regulation. Furthermore, the presence of a SAVED domain that binds cyclic tetra-adenylate in a CRISPR effector reveals a link to the cyclic-oligonucleotide-based antiphage signalling system.
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Affiliation(s)
- Christophe Rouillon
- Institute of Structural Biology, University of Bonn, Bonn, Germany.
- Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany.
| | | | - Haotian Chi
- School of Biology, University of St Andrews, St Andrews, UK
| | - Katja Blumenstock
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn and University Hospital Bonn, Bonn, Germany
| | - Stefano Da Vela
- European Molecular Biology Laboratory (EMBL), Hamburg Site, Hamburg, Germany
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, UK
| | - Jonas Moecking
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Martin F Peter
- Institute of Structural Biology, University of Bonn, Bonn, Germany
| | - Wolfgang Boenigk
- Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany
| | - Reinhard Seifert
- Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, UK
| | - Jonathan L Schmid-Burgk
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn and University Hospital Bonn, Bonn, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Site, Hamburg, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Bonn, Germany
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26
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Kurasz JE, Crawford MC, Porwollik S, Gregory O, Tadlock KR, Balding EC, Weinert EE, McClelland M, Karls AC. Strain-Specific Gifsy-1 Prophage Genes Are Determinants for Expression of the RNA Repair Operon during the SOS Response in Salmonella enterica Serovar Typhimurium. J Bacteriol 2023; 205:e0026222. [PMID: 36622230 PMCID: PMC9879122 DOI: 10.1128/jb.00262-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 12/19/2022] [Indexed: 01/10/2023] Open
Abstract
The adaptation of Salmonella enterica serovar Typhimurium to stress conditions involves expression of genes within the regulon of the alternative sigma factor RpoN (σ54). RpoN-dependent transcription requires an activated bacterial enhancer binding protein (bEBP) that hydrolyzes ATP to remodel the RpoN-holoenzyme-promoter complex for transcription initiation. The bEBP RtcR in S. Typhimurium strain 14028s is activated by genotoxic stress to direct RpoN-dependent expression of the RNA repair operon rsr-yrlBA-rtcBA. The molecular signal for RtcR activation is an oligoribonucleotide with a 3'-terminal 2',3'-cyclic phosphate. We show in S. Typhimurium 14028s that the molecular signal is not a direct product of nucleic acid damage, but signal generation is dependent on a RecA-controlled SOS-response pathway, specifically, induction of prophage Gifsy-1. A genome-wide mutant screen and utilization of Gifsy prophage-cured strains indicated that the nucleoid-associated protein Fis and the Gifsy-1 prophage significantly impact RtcR activation. Directed-deletion analysis and genetic mapping by transduction demonstrated that a three-gene region (STM14_3218-3220) in Gifsy-1, which is variable between S. Typhimurium strains, is required for RtcR activation in strain 14028s and that the absence of STM14_3218-3220 in the Gifsy-1 prophages of S. Typhimurium strains LT2 and 4/74, which renders these strains unable to activate RtcR during genotoxic stress, can be rescued by complementation in cis by the region encompassing STM14_3218-3220. Thus, even though RtcR and the RNA repair operon are highly conserved in Salmonella enterica serovars, RtcR-dependent expression of the RNA repair operon in S. Typhimurium is controlled by a variable region of a prophage present in only some strains. IMPORTANCE The transcriptional activator RtcR and the RNA repair proteins whose expression it regulates, RtcA and RtcB, are widely conserved in Proteobacteria. In Salmonella Typhimurium 14028s, genotoxic stress activates RtcR to direct RpoN-dependent expression of the rsr-yrlBA-rtcBA operon. This work identifies key elements of a RecA-dependent pathway that generates the signal for RtcR activation in strain 14028s. This signaling pathway requires the presence of a specific region within the prophage Gifsy-1, yet this region is absent in most other wild-type Salmonella strains. Thus, we show that the activity of a widely conserved regulatory protein can be controlled by prophages with narrow phylogenetic distributions. This work highlights an underappreciated phenomenon where bacterial physiological functions are altered due to genetic rearrangement of prophages.
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Affiliation(s)
| | | | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California–Irvine School of Medicine, Irvine, California, USA
| | - Oliver Gregory
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | | | - Eve C. Balding
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Emily E. Weinert
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California–Irvine School of Medicine, Irvine, California, USA
| | - Anna C. Karls
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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27
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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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28
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Patel DJ, Yu Y, Jia N. Bacterial origins of cyclic nucleotide-activated antiviral immune signaling. Mol Cell 2022; 82:4591-4610. [PMID: 36460008 PMCID: PMC9772257 DOI: 10.1016/j.molcel.2022.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/25/2022] [Accepted: 11/07/2022] [Indexed: 12/03/2022]
Abstract
Second-messenger-mediated signaling by cyclic oligonucleotides (cOs) composed of distinct base, ring size, and 3'-5'/2'-5' linkage combinations constitutes the initial trigger resulting in activation of signaling pathways that have an impact on immune-mediated antiviral defense against invading viruses and phages. Bacteria and archaea have evolved CRISPR, CBASS, Pycsar, and Thoeris surveillance complexes that involve cO-mediated activation of effectors resulting in antiviral defense through either targeted nuclease activity, effector oligomerization-mediated depletion of essential cellular metabolites or disruption of host cell membrane functions. Notably, antiviral defense capitalizes on an abortive infection mechanism, whereby infected cells die prior to completion of the phage replication cycle. In turn, phages have evolved small proteins that target and degrade/sequester cOs, thereby suppressing host immunity. This review presents a structure-based mechanistic perspective of recent advances in the field of cO-mediated antiviral defense, in particular highlighting the ancient evolutionary adaptation by metazoans of bacterial cell-autonomous innate immune mechanisms.
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Affiliation(s)
- Dinshaw J Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
| | - You Yu
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Ning Jia
- Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China
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29
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Nemudraia A, Nemudryi A, Buyukyoruk M, Scherffius AM, Zahl T, Wiegand T, Pandey S, Nichols JE, Hall LN, McVey A, Lee HH, Wilkinson RA, Snyder LR, Jones JD, Koutmou KS, Santiago-Frangos A, Wiedenheft B. Sequence-specific capture and concentration of viral RNA by type III CRISPR system enhances diagnostic. Nat Commun 2022; 13:7762. [PMID: 36522348 PMCID: PMC9751510 DOI: 10.1038/s41467-022-35445-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Type-III CRISPR-Cas systems have recently been adopted for sequence-specific detection of SARS-CoV-2. Here, we repurpose the type III-A CRISPR complex from Thermus thermophilus (TtCsm) for programmable capture and concentration of specific RNAs from complex mixtures. The target bound TtCsm complex generates two cyclic oligoadenylates (i.e., cA3 and cA4) that allosterically activate ancillary nucleases. We show that both Can1 and Can2 nucleases cleave single-stranded RNA, single-stranded DNA, and double-stranded DNA in the presence of cA4. We integrate the Can2 nuclease with type III-A RNA capture and concentration for direct detection of SARS-CoV-2 RNA in nasopharyngeal swabs with 15 fM sensitivity. Collectively, this work demonstrates how type-III CRISPR-based RNA capture and concentration simultaneously increases sensitivity, limits time to result, lowers cost of the assay, eliminates solvents used for RNA extraction, and reduces sample handling.
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Affiliation(s)
- Anna Nemudraia
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Artem Nemudryi
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Murat Buyukyoruk
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Andrew M. Scherffius
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Trevor Zahl
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Tanner Wiegand
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Shishir Pandey
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Joseph E. Nichols
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Laina N. Hall
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Aidan McVey
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Helen H. Lee
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Royce A. Wilkinson
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Laura R. Snyder
- grid.214458.e0000000086837370Department of Chemistry, University of Michigan, Ann Arbor, MI 48105 USA
| | - Joshua D. Jones
- grid.214458.e0000000086837370Department of Chemistry, University of Michigan, Ann Arbor, MI 48105 USA
| | - Kristin S. Koutmou
- grid.214458.e0000000086837370Department of Chemistry, University of Michigan, Ann Arbor, MI 48105 USA
| | - Andrew Santiago-Frangos
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
| | - Blake Wiedenheft
- grid.41891.350000 0001 2156 6108Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717 USA
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30
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Type III CRISPR-Cas provides resistance against nucleus-forming jumbo phages via abortive infection. Mol Cell 2022; 82:4471-4486.e9. [PMID: 36395770 DOI: 10.1016/j.molcel.2022.10.028] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/13/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022]
Abstract
Bacteria have diverse defenses against phages. In response, jumbo phages evade multiple DNA-targeting defenses by protecting their DNA inside a nucleus-like structure. We previously demonstrated that RNA-targeting type III CRISPR-Cas systems provide jumbo phage immunity by recognizing viral mRNA exported from the nucleus for translation. Here, we demonstrate that recognition of phage mRNA by the type III system activates a cyclic triadenylate-dependent accessory nuclease, NucC. Although unable to access phage DNA in the nucleus, NucC degrades the bacterial chromosome, triggers cell death, and disrupts phage replication and maturation. Hence, type-III-mediated jumbo phage immunity occurs via abortive infection, with suppression of the viral epidemic protecting the population. We further show that type III systems targeting jumbo phages have diverse accessory nucleases, including RNases that provide immunity. Our study demonstrates how type III CRISPR-Cas systems overcome the inaccessibility of jumbo phage DNA to provide robust immunity.
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31
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Ding J, Schuergers N, Baehre H, Wilde A. Enzymatic properties of CARF-domain proteins in Synechocystis sp. PCC 6803. Front Microbiol 2022; 13:1046388. [DOI: 10.3389/fmicb.2022.1046388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated genes) systems provide immunity against invading genetic elements such as bacteriophages and plasmids. In type III CRISPR systems, the recognition of target RNA leads to the synthesis of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins via their CRISPR-associated Rossmann fold (CARF) domains. Commonly, these are ribonucleases (RNases) that unspecifically degrade both invader and host RNA. To mitigate adverse effects on cell growth, ring nucleases can degrade extant cOAs to switch off ancillary nucleases. Here we show that the model organism Synechocystis sp. PCC 6803 harbors functional CARF-domain effector and ring nuclease proteins. We purified and characterized the two ancillary CARF-domain proteins from the III-D type CRISPR system of this cyanobacterium. The Csx1 homolog, SyCsx1, is a cyclic tetraadenylate(cA4)-dependent RNase with a strict specificity for cytosine nucleotides. The second CARF-domain protein with similarity to Csm6 effectors, SyCsm6, did not show RNase activity in vitro but was able to break down cOAs and attenuate SyCsx1 RNase activity. Our data suggest that the CRISPR systems in Synechocystis confer a multilayered cA4-mediated defense mechanism.
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32
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Steens JA, Salazar CRP, Staals RH. The diverse arsenal of type III CRISPR-Cas-associated CARF and SAVED effectors. Biochem Soc Trans 2022; 50:1353-1364. [PMID: 36282000 PMCID: PMC9704534 DOI: 10.1042/bst20220289] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/28/2022] [Accepted: 10/10/2022] [Indexed: 09/14/2023]
Abstract
Type III CRISPR-Cas systems make use of a multi-subunit effector complex to target foreign (m)RNA transcripts complementary to the guide/CRISPR RNA (crRNA). Base-pairing of the target RNA with specialized regions in the crRNA not only triggers target RNA cleavage, but also activates the characteristic Cas10 subunit and sets in motion a variety of catalytic activities that starts with the production of cyclic oligoadenylate (cOA) second messenger molecules. These messenger molecules can activate an extensive arsenal of ancillary effector proteins carrying the appropriate sensory domain. Notably, the CARF and SAVED effector proteins have been responsible for renewed interest in type III CRISPR-Cas due to the extraordinary diversity of defenses against invading genetic elements. Whereas only a handful of CARF and SAVED proteins have been studied so far, many of them seem to provoke abortive infection, aimed to kill the host and provide population-wide immunity. A defining feature of these effector proteins is the variety of in silico-predicted catalytic domains they are fused to. In this mini-review, we discuss all currently characterized type III-associated CARF and SAVED effector proteins, highlight a few examples of predicted CARF and SAVED proteins with interesting predicted catalytic activities, and speculate how they could contribute to type III immunity.
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Affiliation(s)
- Jurre A. Steens
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | | | - Raymond H.J. Staals
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
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33
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Molina R, Garcia-Martin R, López-Méndez B, Jensen ALG, Ciges-Tomas JR, Marchena-Hurtado J, Stella S, Montoya G. Molecular basis of cyclic tetra-oligoadenylate processing by small standalone CRISPR-Cas ring nucleases. Nucleic Acids Res 2022; 50:11199-11213. [PMID: 36271789 PMCID: PMC9638899 DOI: 10.1093/nar/gkac923] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 11/24/2022] Open
Abstract
Standalone ring nucleases are CRISPR ancillary proteins, which downregulate the immune response of Type III CRISPR-Cas systems by cleaving cyclic oligoadenylates (cA) second messengers. Two genes with this function have been found within the Sulfolobus islandicus (Sis) genome. They code for a long polypeptide composed by a CARF domain fused to an HTH domain and a short polypeptide constituted by a CARF domain with a 40 residue C-terminal insertion. Here, we determine the structure of the apo and substrate bound states of the Sis0455 enzyme, revealing an insertion at the C-terminal region of the CARF domain, which plays a key role closing the catalytic site upon substrate binding. Our analysis reveals the key residues of Sis0455 during cleavage and the coupling of the active site closing with their positioning to proceed with cA4 phosphodiester hydrolysis. A time course comparison of cA4 cleavage between the short, Sis0455, and long ring nucleases, Sis0811, shows the slower cleavage kinetics of the former, suggesting that the combination of these two types of enzymes with the same function in a genome could be an evolutionary strategy to regulate the levels of the second messenger in different infection scenarios.
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Affiliation(s)
- Rafael Molina
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - Ricardo Garcia-Martin
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - Blanca López-Méndez
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Anne Louise Grøn Jensen
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - J Rafael Ciges-Tomas
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - Javier Marchena-Hurtado
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - Stefano Stella
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark
| | - Guillermo Montoya
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, 2200 Copenhagen, Denmark.,The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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34
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Abstract
Advances in our understanding of prokaryotic antiphage defense mechanisms in the past few years have revealed a multitude of new cyclic nucleotide signaling molecules that play a crucial role in switching infected cells into an antiviral state. Defense pathways including type III CRISPR (clustered regularly interspaced palindromic repeats), CBASS (cyclic nucleotide-based antiphage signaling system), PYCSAR (pyrimidine cyclase system for antiphage resistance), and Thoeris all use cyclic nucleotides as second messengers to activate a diverse range of effector proteins. These effectors typically degrade or disrupt key cellular components such as nucleic acids, membranes, or metabolites, slowing down viral replication kinetics at great cost to the infected cell. Mechanisms to manipulate the levels of cyclic nucleotides are employed by cells to regulate defense pathways and by viruses to subvert them. Here we review the discovery and mechanism of the key pathways, signaling molecules and effectors, parallels and differences between the systems, open questions, and prospects for future research in this area.
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Affiliation(s)
- Januka S Athukoralage
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Malcolm F White
- School of Biology, University of St Andrews, St Andrews, United Kingdom;
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35
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Hu C, van Beljouw SPB, Nam KH, Schuler G, Ding F, Cui Y, Rodríguez-Molina A, Haagsma AC, Valk M, Pabst M, Brouns SJ, Ke A. Craspase is a CRISPR RNA-guided, RNA-activated protease. Science 2022; 377:1278-1285. [PMID: 36007061 PMCID: PMC10041820 DOI: 10.1126/science.add5064] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The CRISPR-Cas type III-E RNA-targeting effector complex gRAMP/Cas7-11 is associated with a caspase-like protein (TPR-CHAT/Csx29) to form Craspase (CRISPR-guided caspase). Here, we use cryo-electron microscopy snapshots of Craspase to explain its target RNA cleavage and protease activation mechanisms. Target-guide pairing extending into the 5' region of the guide RNA displaces a gating loop in gRAMP, which triggers an extensive conformational relay that allosterically aligns the protease catalytic dyad and opens an amino acid side-chain-binding pocket. We further define Csx30 as the endogenous protein substrate that is site-specifically proteolyzed by RNA-activated Craspase. This protease activity is switched off by target RNA cleavage by gRAMP and is not activated by RNA targets containing a matching protospacer flanking sequence. We thus conclude that Craspase is a target RNA-activated protease with self-regulatory capacity.
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Affiliation(s)
- Chunyi Hu
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA
| | - Sam P. B. van Beljouw
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
- Kavli Institute of Nanoscience, Delft, Netherlands
| | - Ki Hyun Nam
- Department of Life Science, Pohang University of Science and Technology, Pohang, Gyeongbuk, Republic of Korea
| | - Gabriel Schuler
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA
| | - Fran Ding
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA
| | - Yanru Cui
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA
| | - Alicia Rodríguez-Molina
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
- Kavli Institute of Nanoscience, Delft, Netherlands
| | - Anna C Haagsma
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
- Kavli Institute of Nanoscience, Delft, Netherlands
| | - Menno Valk
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
- Kavli Institute of Nanoscience, Delft, Netherlands
| | - Martin Pabst
- Department of Environmental Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Stan J.J. Brouns
- Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
- Kavli Institute of Nanoscience, Delft, Netherlands
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA
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36
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Gao LA, Wilkinson ME, Strecker J, Makarova KS, Macrae RK, Koonin EV, Zhang F. Prokaryotic innate immunity through pattern recognition of conserved viral proteins. Science 2022; 377:eabm4096. [PMID: 35951700 PMCID: PMC10028730 DOI: 10.1126/science.abm4096] [Citation(s) in RCA: 92] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Many organisms have evolved specialized immune pattern-recognition receptors, including nucleotide-binding oligomerization domain-like receptors (NLRs) of the STAND superfamily that are ubiquitous in plants, animals, and fungi. Although the roles of NLRs in eukaryotic immunity are well established, it is unknown whether prokaryotes use similar defense mechanisms. Here, we show that antiviral STAND (Avs) homologs in bacteria and archaea detect hallmark viral proteins, triggering Avs tetramerization and the activation of diverse N-terminal effector domains, including DNA endonucleases, to abrogate infection. Cryo-electron microscopy reveals that Avs sensor domains recognize conserved folds, active-site residues, and enzyme ligands, allowing a single Avs receptor to detect a wide variety of viruses. These findings extend the paradigm of pattern recognition of pathogen-specific proteins across all three domains of life.
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Affiliation(s)
- Linyi Alex Gao
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research
- Department of Brain and Cognitive Sciences
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Society of Fellows, Harvard University, Cambridge, MA 02138, USA
- Correspondence: (F.Z.) or (L.A.G.)
| | - Max E. Wilkinson
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research
- Department of Brain and Cognitive Sciences
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jonathan Strecker
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research
- Department of Brain and Cognitive Sciences
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Rhiannon K. Macrae
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research
- Department of Brain and Cognitive Sciences
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Feng Zhang
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- McGovern Institute for Brain Research
- Department of Brain and Cognitive Sciences
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Correspondence: (F.Z.) or (L.A.G.)
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37
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Cyclic nucleotide-induced helical structure activates a TIR immune effector. Nature 2022; 608:808-812. [PMID: 35948638 DOI: 10.1038/s41586-022-05070-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 07/01/2022] [Indexed: 02/02/2023]
Abstract
Cyclic nucleotide signalling is a key component of antiviral defence in all domains of life. Viral detection activates a nucleotide cyclase to generate a second messenger, resulting in activation of effector proteins. This is exemplified by the metazoan cGAS-STING innate immunity pathway1, which originated in bacteria2. These defence systems require a sensor domain to bind the cyclic nucleotide and are often coupled with an effector domain that, when activated, causes cell death by destroying essential biomolecules3. One example is the Toll/interleukin-1 receptor (TIR) domain, which degrades the essential cofactor NAD+ when activated in response to infection in plants and bacteria2,4,5 or during programmed nerve cell death6. Here we show that a bacterial antiviral defence system generates a cyclic tri-adenylate that binds to a TIR-SAVED effector, acting as the 'glue' to allow assembly of an extended superhelical solenoid structure. Adjacent TIR subunits interact to organize and complete a composite active site, allowing NAD+ degradation. Activation requires extended filament formation, both in vitro and in vivo. Our study highlights an example of large-scale molecular assembly controlled by cyclic nucleotides and reveals key details of the mechanism of TIR enzyme activation.
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38
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Nemudraia A, Nemudryi A, Buyukyoruk M, Scherffius AM, Zahl T, Wiegand T, Pandey S, Nichols JE, Hall L, McVey A, Lee HH, Wilkinson RA, Snyder LR, Jones JD, Koutmou KS, Santiago-Frangos A, Wiedenheft B. Sequence-specific capture and concentration of viral RNA by type III CRISPR system enhances diagnostic. RESEARCH SQUARE 2022:rs.3.rs-1466718. [PMID: 35475170 PMCID: PMC9040678 DOI: 10.21203/rs.3.rs-1466718/v1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Type-III CRISPR-Cas systems have recently been adopted for sequence-specific detection of SARS-CoV-2. Here, we make two major advances that simultaneously limit sample handling and significantly enhance the sensitivity of SARS-CoV-2 RNA detection directly from patient samples. First, we repurpose the type III-A CRISPR complex from Thermus thermophilus (TtCsm) for programmable capture and concentration of specific RNAs from complex mixtures. The target bound TtCsm complex primarily generates two cyclic oligoadenylates (i.e., cA3 and cA4) that allosterically activate ancillary nucleases. To improve sensitivity of the diagnostic, we identify and test several ancillary nucleases (i.e., Can1, Can2, and NucC). We show that Can1 and Can2 are activated by both cA3 and cA4, and that different activators trigger changes in the substrate specificity of these nucleases. Finally, we integrate the type III-A CRISPR RNA-guided capture technique with the Can2 nuclease for 90 fM (5x104 copies/ul) detection of SARS-CoV-2 RNA directly from nasopharyngeal swab samples.
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Affiliation(s)
- Anna Nemudraia
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,These authors contributed equally
| | - Artem Nemudryi
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,These authors contributed equally
| | - Murat Buyukyoruk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,These authors contributed equally
| | - Andrew M. Scherffius
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,These authors contributed equally
| | - Trevor Zahl
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Tanner Wiegand
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Shishir Pandey
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Joseph E. Nichols
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Laina Hall
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Aidan McVey
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Helen H Lee
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Royce A. Wilkinson
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Laura R. Snyder
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48105, USA
| | - Joshua D. Jones
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48105, USA
| | - Kristin S. Koutmou
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48105, USA
| | - Andrew Santiago-Frangos
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,Correspondence: and
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA,Lead contact,Correspondence: and
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Zhang X, An X. Adaptation by Type III CRISPR-Cas Systems: Breakthrough Findings and Open Questions. Front Microbiol 2022; 13:876174. [PMID: 35495695 PMCID: PMC9048733 DOI: 10.3389/fmicb.2022.876174] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/03/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems acquire heritable defense memory against invading nucleic acids through adaptation. Type III CRISPR-Cas systems have unique and intriguing features of defense and are important in method development for Genetics research. We started to understand the common and unique properties of type III CRISPR-Cas adaptation in recent years. This review summarizes our knowledge regarding CRISPR-Cas adaptation with the emphasis on type III systems and discusses open questions for type III adaptation studies.
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Affiliation(s)
- Xinfu Zhang
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, United States
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- *Correspondence: Xinfu Zhang,
| | - Xinmin An
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- Xinmin An,
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40
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Xia P, Dutta A, Gupta K, Batish M, Parashar V. Structural basis of cyclic oligoadenylate binding to the transcription factor Csa3 outlines cross talk between type III and type I CRISPR systems. J Biol Chem 2022; 298:101591. [PMID: 35038453 PMCID: PMC8844856 DOI: 10.1016/j.jbc.2022.101591] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 01/28/2023] Open
Abstract
RNA interference by type III CRISPR systems results in the synthesis of cyclic oligoadenylate (cOA) second messengers, which are known to bind and regulate various CARF domain-containing nuclease receptors. The CARF domain-containing Csa3 family of transcriptional factors associated with the DNA-targeting type I CRISPR systems regulate expression of various CRISPR and DNA repair genes in many prokaryotes. In this study, we extend the known receptor repertoire of cOA messengers to include transcriptional factors by demonstrating specific binding of cyclic tetra-adenylate (cA4) to Saccharolobus solfataricus Csa3 (Csa3Sso). Our 2.0-Å resolution X-ray crystal structure of cA4-bound full-length Csa3Sso reveals the binding of its CARF domain to an elongated conformation of cA4. Using cA4 binding affinity analyses of Csa3Sso mutants targeting the observed Csa3Sso•cA4 structural interface, we identified a Csa3-specific cA4 binding motif distinct from a more widely conserved cOA-binding CARF motif. Using a rational surface engineering approach, we increased the cA4 binding affinity of Csa3Sso up to ∼145-fold over the wildtype, which has potential applications for future second messenger-driven CRISPR gene expression and editing systems. Our in-solution Csa3Sso structural analysis identified cA4-induced allosteric and asymmetric conformational rearrangement of its C-terminal winged helix-turn-helix effector domains, which could potentially be incompatible to DNA binding. However, specific in vitro binding of the purified Csa3Sso to its putative promoter (PCas4a) was found to be cA4 independent, suggesting a complex mode of Csa3Sso regulation. Overall, our results support cA4-and Csa3-mediated cross talk between type III and type I CRISPR systems.
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Affiliation(s)
- Pengjun Xia
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Anirudha Dutta
- Department of Medical and Molecular Sciences, University of Delaware, Newark, Delaware, USA
| | - Kushol Gupta
- The Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mona Batish
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Medical and Molecular Sciences, University of Delaware, Newark, Delaware, USA
| | - Vijay Parashar
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA; Department of Medical and Molecular Sciences, University of Delaware, Newark, Delaware, USA.
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41
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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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42
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Abstract
The principal biological function of bacterial and archaeal CRISPR systems is RNA-guided adaptive immunity against viruses and other mobile genetic elements (MGEs). These systems show remarkable evolutionary plasticity and functional versatility at multiple levels, including both the defense mechanisms that lead to direct, specific elimination of the target DNA or RNA and those that cause programmed cell death (PCD) or induction of dormancy. This flexibility is also evident in the recruitment of CRISPR systems for nondefense functions. Defective CRISPR systems or individual CRISPR components have been recruited by transposons for RNA-guided transposition, by plasmids for interplasmid competition, and by viruses for antidefense and interviral conflicts. Additionally, multiple highly derived CRISPR variants of yet unknown functions have been discovered. A major route of innovation in CRISPR evolution is the repurposing of diverged repeat variants encoded outside CRISPR arrays for various structural and regulatory functions. The evolutionary plasticity and functional versatility of CRISPR systems are striking manifestations of the ubiquitous interplay between defense and “normal” cellular functions. The CRISPR systems show remarkable functional versatility beyond their principal function as an adaptive immune mechanism. This Essay discusses how derived CRISPR systems have been recruited by transposons on multiple occasions and mediate RNA-guided transposition; derived CRISPR RNAs are frequently recruited for regulatory functions.
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Affiliation(s)
- Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
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43
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Chou-Zheng L, Hatoum-Aslan A. Critical roles for 'housekeeping' nucleases in type III CRISPR-Cas immunity. eLife 2022; 11:81897. [PMID: 36479971 PMCID: PMC9762709 DOI: 10.7554/elife.81897] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
CRISPR-Cas systems are a family of adaptive immune systems that use small CRISPR RNAs (crRNAs) and CRISPR-associated (Cas) nucleases to protect prokaryotes from invading plasmids and viruses (i.e., phages). Type III systems launch a multilayered immune response that relies upon both Cas and non-Cas cellular nucleases, and although the functions of Cas components have been well described, the identities and roles of non-Cas participants remain poorly understood. Previously, we showed that the type III-A CRISPR-Cas system in Staphylococcus epidermidis employs two degradosome-associated nucleases, PNPase and RNase J2, to promote crRNA maturation and eliminate invading nucleic acids (Chou-Zheng and Hatoum-Aslan, 2019). Here, we identify RNase R as a third 'housekeeping' nuclease critical for immunity. We show that RNase R works in concert with PNPase to complete crRNA maturation and identify specific interactions with Csm5, a member of the type III effector complex, which facilitate nuclease recruitment/stimulation. Furthermore, we demonstrate that RNase R and PNPase are required to maintain robust anti-plasmid immunity, particularly when targeted transcripts are sparse. Altogether, our findings expand the known repertoire of accessory nucleases required for type III immunity and highlight the remarkable capacity of these systems to interface with diverse cellular pathways to ensure successful defense.
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Affiliation(s)
- Lucy Chou-Zheng
- Microbiology Department, University of Illinois Urbana-ChampaignUrbanaUnited States
| | - Asma Hatoum-Aslan
- Microbiology Department, University of Illinois Urbana-ChampaignUrbanaUnited States
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44
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Cargo Genes of Tn 7-Like Transposons Comprise an Enormous Diversity of Defense Systems, Mobile Genetic Elements, and Antibiotic Resistance Genes. mBio 2021; 12:e0293821. [PMID: 34872347 PMCID: PMC8649781 DOI: 10.1128/mbio.02938-21] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Transposition is a major mechanism of horizontal gene mobility in prokaryotes. However, exploration of the genes mobilized by transposons (cargo) is hampered by the difficulty in delineating integrated transposons from their surrounding genetic context. Here, we present a computational approach that allowed us to identify the boundaries of 6,549 Tn7-like transposons. We found that 96% of these transposons carry at least one cargo gene. Delineation of distinct communities in a gene-sharing network demonstrates how transposons function as a conduit of genes between phylogenetically distant hosts. Comparative analysis of the cargo genes reveals significant enrichment of mobile genetic elements (MGEs) nested within Tn7-like transposons, such as insertion sequences and toxin-antitoxin modules, and of genes involved in recombination, anti-MGE defense, and antibiotic resistance. More unexpectedly, cargo also includes genes encoding central carbon metabolism enzymes. Twenty-two Tn7-like transposons carry both an anti-MGE defense system and antibiotic resistance genes, illustrating how bacteria can overcome these combined pressures upon acquisition of a single transposon. This work substantially expands the distribution of Tn7-like transposons, defines their evolutionary relationships, and provides a large-scale functional classification of prokaryotic genes mobilized by transposition.
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45
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Charbonneau AA, Eckert DM, Gauvin CC, Lintner NG, Lawrence CM. Cyclic Tetra-Adenylate (cA 4) Recognition by Csa3; Implications for an Integrated Class 1 CRISPR-Cas Immune Response in Saccharolobus solfataricus. Biomolecules 2021; 11:biom11121852. [PMID: 34944496 PMCID: PMC8699464 DOI: 10.3390/biom11121852] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 01/09/2023] Open
Abstract
Csa3 family transcription factors are ancillary CRISPR-associated proteins composed of N-terminal CARF domains and C-terminal winged helix-turn-helix domains. The activity of Csa3 transcription factors is thought to be controlled by cyclic oligoadenyate (cOA) second messengers produced by type III CRISPR-Cas surveillance complexes. Here we show that Saccharolobus solfataricus Csa3a recognizes cyclic tetra-adenylate (cA4) and that Csa3a lacks self-regulating "ring nuclease" activity present in some other CARF domain proteins. The crystal structure of the Csa3a/cA4 complex was also determined and the structural and thermodynamic basis for cA4 recognition are described, as are conformational changes in Csa3a associated with cA4 binding. We also characterized the effect of cA4 on recognition of putative DNA binding sites. Csa3a binds to putative promoter sequences in a nonspecific, cooperative and cA4-independent manner, suggesting a more complex mode of transcriptional regulation. We conclude the Csa3a/cA4 interaction represents a nexus between the type I and type III CRISPR-Cas systems present in S. solfataricus, and discuss the role of the Csa3/cA4 interaction in coordinating different arms of this integrated class 1 immune system to mount a synergistic, highly orchestrated immune response.
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Affiliation(s)
- Alexander A. Charbonneau
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA; (A.A.C.); (C.C.G.); (N.G.L.)
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA
| | - Debra M. Eckert
- School of Medicine, University of Utah, Salt Lake City, UT 84112, USA;
| | - Colin C. Gauvin
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA; (A.A.C.); (C.C.G.); (N.G.L.)
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA
| | - Nathanael G. Lintner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA; (A.A.C.); (C.C.G.); (N.G.L.)
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA
| | - C. Martin Lawrence
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA; (A.A.C.); (C.C.G.); (N.G.L.)
- Thermal Biology Institute, Montana State University, Bozeman, MT 59717, USA
- Correspondence: ; Tel.: +1-406-994-5382
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46
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Molina R, Jensen ALG, Marchena-Hurtado J, López-Méndez B, Stella S, Montoya G. Structural basis of cyclic oligoadenylate degradation by ancillary Type III CRISPR-Cas ring nucleases. Nucleic Acids Res 2021; 49:12577-12590. [PMID: 34850143 PMCID: PMC8643638 DOI: 10.1093/nar/gkab1130] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 12/26/2022] Open
Abstract
Type III CRISPR-Cas effector systems detect foreign RNA triggering DNA and RNA cleavage and synthesizing cyclic oligoadenylate molecules (cA) in their Cas10 subunit. cAs act as a second messenger activating auxiliary nucleases, leading to an indiscriminate RNA degradation that can end in cell dormancy or death. Standalone ring nucleases are CRISPR ancillary proteins which downregulate the strong immune response of Type III systems by degrading cA. These enzymes contain a CRISPR-associated Rossman-fold (CARF) domain, which binds and cleaves the cA molecule. Here, we present the structures of the standalone ring nuclease from Sulfolobus islandicus (Sis) 0811 in its apo and post-catalytic states. This enzyme is composed by a N-terminal CARF and a C-terminal wHTH domain. Sis0811 presents a phosphodiester hydrolysis metal-independent mechanism, which cleaves cA4 rings to generate linear adenylate species, thus reducing the levels of the second messenger and switching off the cell antiviral state. The structural and biochemical analysis revealed the coupling of a cork-screw conformational change with the positioning of key catalytic residues to proceed with cA4 phosphodiester hydrolysis in a non-concerted manner.
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Affiliation(s)
- Rafael Molina
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, Copenhagen, 2200, Denmark
| | - Anne Louise Grøn Jensen
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, Copenhagen, 2200, Denmark
| | - Javier Marchena-Hurtado
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, Copenhagen, 2200, Denmark
| | - Blanca López-Méndez
- The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Stefano Stella
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, Copenhagen, 2200, Denmark
| | - Guillermo Montoya
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences University of Copenhagen, Blegdamsvej 3-B, Copenhagen, 2200, Denmark.,The Novo Nordisk Foundation Center for Protein Research, Protein Structure & Function Programme, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
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47
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Molecular mechanisms of the CdnG-Cap5 antiphage defense system employing 3',2'-cGAMP as the second messenger. Nat Commun 2021; 12:6381. [PMID: 34737303 PMCID: PMC8568899 DOI: 10.1038/s41467-021-26738-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/20/2021] [Indexed: 12/04/2022] Open
Abstract
Cyclic-oligonucleotide-based antiphage signaling systems (CBASS) are diverse and abundant in bacteria. Here, we present the biochemical and structural characterization of two CBASS systems, composed of CdnG and Cap5, from Asticcacaulis sp. and Lactococcus lactis. We show that CdnG from Asticcacaulis sp. synthesizes 3′,2′-cGAMP in vitro, and 3′,2′-cGAMP is the biological signaling molecule that activates Cap5 for DNA degradation. Crystal structures of Cap5, together with the SAVED domain in complex with 3′,2′-cGAMP, provide insight into the architecture of Cap5 as well as molecular recognition of 3′,2′-cGAMP by the SAVED domain of Cap5. Amino acid conservation of the SAVED domain of Cap5, together with mutational studies, led us to propose a mechanism of Back-to-Front stacking of two SAVED domains, mediated by 3′,2′-cGAMP, to activate HNH nuclease domain for DNA degradation. This study of the most abundant CBASS system provides insights into the mechanisms employed by bacteria in their conflicts against phage. Many bacterial cyclic-oligonucleotide-based antiphage signaling systems (CBASS) employ effectors with SAVED domains. Here, the authors present a biochemical and structural characterization of two such CBASS, providing mechanistic insights into bacterial antiphage defense.
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48
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Egido JE, Costa AR, Aparicio-Maldonado C, Haas PJ, Brouns SJJ. Mechanisms and clinical importance of bacteriophage resistance. FEMS Microbiol Rev 2021; 46:6374866. [PMID: 34558600 PMCID: PMC8829019 DOI: 10.1093/femsre/fuab048] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/15/2021] [Indexed: 12/24/2022] Open
Abstract
We are in the midst of a golden age of uncovering defense systems against bacteriophages. Apart from the fundamental interest in these defense systems, and revolutionary applications that have been derived from them (e.g. CRISPR-Cas9 and restriction endonucleases), it is unknown how defense systems contribute to resistance formation against bacteriophages in clinical settings. Bacteriophages are now being reconsidered as therapeutic agents against bacterial infections due the emergence of multidrug resistance. However, bacteriophage resistance through defense systems and other means could hinder the development of successful phage-based therapies. Here, we review the current state of the field of bacteriophage defense, highlight the relevance of bacteriophage defense for potential clinical use of bacteriophages as therapeutic agents and suggest new directions of research.
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Affiliation(s)
- Julia E Egido
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Ana Rita Costa
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands.,Fagenbank, Delft, Netherlands
| | - Cristian Aparicio-Maldonado
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands
| | - Pieter-Jan Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands.,Fagenbank, Delft, Netherlands
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49
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Estimating maximal microbial growth rates from cultures, metagenomes, and single cells via codon usage patterns. Proc Natl Acad Sci U S A 2021; 118:2016810118. [PMID: 33723043 PMCID: PMC8000110 DOI: 10.1073/pnas.2016810118] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Despite the wide perception that microbes have rapid growth rates, many environments like seawater and soil are often dominated by microorganisms that can only grow very slowly. Our knowledge about growth is necessarily biased toward easily culturable organisms, which tend to be those that grow fast, because microbial growth rates have traditionally been measured using laboratory growth experiments. However, how are potential growth rates distributed in nature? Using genomic data, we predicted the growth rates of over 200,000 organisms, including many as yet uncultivated species. These data reveal how current culture collections are strongly biased toward fast-growing organisms. Finally, we noticed a bimodal distribution of maximal growth rates, suggesting a natural division of microbial growth strategies into two classes. Maximal growth rate is a basic parameter of microbial lifestyle that varies over several orders of magnitude, with doubling times ranging from a matter of minutes to multiple days. Growth rates are typically measured using laboratory culture experiments. Yet, we lack sufficient understanding of the physiology of most microbes to design appropriate culture conditions for them, severely limiting our ability to assess the global diversity of microbial growth rates. Genomic estimators of maximal growth rate provide a practical solution to survey the distribution of microbial growth potential, regardless of cultivation status. We developed an improved maximal growth rate estimator and predicted maximal growth rates from over 200,000 genomes, metagenome-assembled genomes, and single-cell amplified genomes to survey growth potential across the range of prokaryotic diversity; extensions allow estimates from 16S rRNA sequences alone as well as weighted community estimates from metagenomes. We compared the growth rates of cultivated and uncultivated organisms to illustrate how culture collections are strongly biased toward organisms capable of rapid growth. Finally, we found that organisms naturally group into two growth classes and observed a bias in growth predictions for extremely slow-growing organisms. These observations ultimately led us to suggest evolutionary definitions of oligotrophy and copiotrophy based on the selective regime an organism occupies. We found that these growth classes are associated with distinct selective regimes and genomic functional potentials.
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50
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Santiago-Frangos A, Hall LN, Nemudraia A, Nemudryi A, Krishna P, Wiegand T, Wilkinson RA, Snyder DT, Hedges JF, Cicha C, Lee HH, Graham A, Jutila MA, Taylor MP, Wiedenheft B. Intrinsic signal amplification by type III CRISPR-Cas systems provides a sequence-specific SARS-CoV-2 diagnostic. Cell Rep Med 2021; 2:100319. [PMID: 34075364 PMCID: PMC8157118 DOI: 10.1016/j.xcrm.2021.100319] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 12/23/2022]
Abstract
There is an urgent need for inexpensive new technologies that enable fast, reliable, and scalable detection of viruses. Here, we repurpose the type III CRISPR-Cas system for sensitive and sequence-specific detection of SARS-CoV-2. RNA recognition by the type III CRISPR complex triggers Cas10-mediated polymerase activity, which simultaneously generates pyrophosphates, protons, and cyclic oligonucleotides. We show that all three Cas10-polymerase products are detectable using colorimetric or fluorometric readouts. We design ten guide RNAs that target conserved regions of SARS-CoV-2 genomes. Multiplexing improves the sensitivity of amplification-free RNA detection from 107 copies/μL for a single guide RNA to 106 copies/μL for ten guides. To decrease the limit of detection to levels that are clinically relevant, we developed a two-pot reaction consisting of RT-LAMP followed by T7-transcription and type III CRISPR-based detection. The two-pot reaction has a sensitivity of 200 copies/μL and is completed using patient samples in less than 30 min.
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Affiliation(s)
| | - Laina N. Hall
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Anna Nemudraia
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Artem Nemudryi
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Pushya Krishna
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Tanner Wiegand
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Royce A. Wilkinson
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Deann T. Snyder
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Jodi F. Hedges
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Calvin Cicha
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Helen H. Lee
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Ava Graham
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Mark A. Jutila
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Matthew P. Taylor
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
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