1
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Jiang C, Yu C, Sun S, Lin J, Cai M, Wei Z, Feng L, Li J, Zhang Y, Dong K, Guo X, Qin J, Zhang Y. A new anti-CRISPR gene promotes the spread of drug-resistance plasmids in Klebsiella pneumoniae. Nucleic Acids Res 2024; 52:8370-8384. [PMID: 38888121 DOI: 10.1093/nar/gkae516] [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: 03/18/2024] [Revised: 05/25/2024] [Accepted: 06/07/2024] [Indexed: 06/20/2024] Open
Abstract
The Klebsiella pneumoniae (K. pneumoniae, Kp) populations carrying both resistance-encoding and virulence-encoding mobile genetic elements (MGEs) significantly threaten global health. In this study, we identified a new anti-CRISPR gene (acrIE10) on a conjugative plasmid with self-target sequence in K. pneumoniae with type I-E* CRISPR-Cas system. AcrIE10 interacts with the Cas7* subunit of K. pneumoniae I-E* CRISPR-Cas system. The crystal structure of the AcrIE10-KpCas7* complex suggests that AcrIE10 suppresses the I-E* CRISPR-Cas by binding directly to Cas7 to prevent its hexamerization, thereby preventing the surveillance complex assembly and crRNA loading. Bioinformatic and functional analyses revealed that AcrIE10 is functionally widespread across diverse species. Our study reports a novel anti-CRISPR and highlights its potential role in spreading resistance and virulence among pathogens.
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Affiliation(s)
- Chunyu Jiang
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Chengzhi Yu
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuyi Sun
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiajia Lin
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Mufeng Cai
- Shanghai Immune Therapy Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Zhenquan Wei
- Core Facility of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lingling Feng
- Core Facility of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jianhui Li
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Yan Zhang
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Ke Dong
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiaokui Guo
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jinhong Qin
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
- NHC Key Laboratory of Parasite and Vector Biology (National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention), Shanghai 200025, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Design, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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2
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Trost CN, Yang J, Garcia B, Hidalgo-Reyes Y, Fung BCM, Wang J, Lu WT, Maxwell KL, Wang Y, Davidson AR. An anti-CRISPR that pulls apart a CRISPR-Cas complex. Nature 2024; 632:375-382. [PMID: 38961300 DOI: 10.1038/s41586-024-07642-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 05/31/2024] [Indexed: 07/05/2024]
Abstract
In biological systems, the activities of macromolecular complexes must sometimes be turned off. Thus, a wide variety of protein inhibitors has evolved for this purpose. These inhibitors function through diverse mechanisms, including steric blocking of crucial interactions, enzymatic modification of key residues or substrates, and perturbation of post-translational modifications1. Anti-CRISPRs-proteins that block the activity of CRISPR-Cas systems-are one of the largest groups of inhibitors described, with more than 90 families that function through diverse mechanisms2-4. Here, we characterize the anti-CRISPR AcrIF25, and we show that it inhibits the type I-F CRISPR-Cas system by pulling apart the fully assembled effector complex. AcrIF25 binds to the predominant CRISPR RNA-binding components of this complex, comprising six Cas7 subunits, and strips them from the RNA. Structural and biochemical studies indicate that AcrIF25 removes one Cas7 subunit at a time, starting at one end of the complex. Notably, this feat is achieved with no apparent enzymatic activity. To our knowledge, AcrIF25 is the first example of a protein that disassembles a large and stable macromolecular complex in the absence of an external energy source. As such, AcrIF25 establishes a paradigm for macromolecular complex inhibitors that may be used for biotechnological applications.
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Affiliation(s)
- Chantel N Trost
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jing Yang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Bianca Garcia
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Yurima Hidalgo-Reyes
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Beatrice C M Fung
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jiuyu Wang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wang-Ting Lu
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yanli Wang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- University of the Chinese Academy of Sciences, Beijing, China.
| | - Alan R Davidson
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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3
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Beamud B, Benz F, Bikard D. Going viral: The role of mobile genetic elements in bacterial immunity. Cell Host Microbe 2024; 32:804-819. [PMID: 38870898 DOI: 10.1016/j.chom.2024.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/15/2024]
Abstract
Bacteriophages and other mobile genetic elements (MGEs) pose a significant threat to bacteria, subjecting them to constant attacks. In response, bacteria have evolved a sophisticated immune system that employs diverse defensive strategies and mechanisms. Remarkably, a growing body of evidence suggests that most of these defenses are encoded by MGEs themselves. This realization challenges our traditional understanding of bacterial immunity and raises intriguing questions about the evolutionary forces at play. Our review provides a comprehensive overview of the latest findings on the main families of MGEs and the defense systems they encode. We also highlight how a vast diversity of defense systems remains to be discovered and their mechanism of mobility understood. Altogether, the composition and distribution of defense systems in bacterial genomes only makes sense in the light of the ecological and evolutionary interactions of a complex network of MGEs.
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Affiliation(s)
- Beatriz Beamud
- Institut Pasteur, Université de Paris, Synthetic Biology, 75015 Paris, France.
| | - Fabienne Benz
- Institut Pasteur, Université de Paris, Synthetic Biology, 75015 Paris, France; Institut Pasteur, Université Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, 75015 Paris, France
| | - David Bikard
- Institut Pasteur, Université de Paris, Synthetic Biology, 75015 Paris, France.
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4
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Mayo-Muñoz D, Pinilla-Redondo R, Camara-Wilpert S, Birkholz N, Fineran PC. Inhibitors of bacterial immune systems: discovery, mechanisms and applications. Nat Rev Genet 2024; 25:237-254. [PMID: 38291236 DOI: 10.1038/s41576-023-00676-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2023] [Indexed: 02/01/2024]
Abstract
To contend with the diversity and ubiquity of bacteriophages and other mobile genetic elements, bacteria have developed an arsenal of immune defence mechanisms. Bacterial defences include CRISPR-Cas, restriction-modification and a growing list of mechanistically diverse systems, which constitute the bacterial 'immune system'. As a response, bacteriophages and mobile genetic elements have evolved direct and indirect mechanisms to circumvent or block bacterial defence pathways and ensure successful infection. Recent advances in methodological and computational approaches, as well as the increasing availability of genome sequences, have boosted the discovery of direct inhibitors of bacterial defence systems. In this Review, we discuss methods for the discovery of direct inhibitors, their diverse mechanisms of action and perspectives on their emerging applications in biotechnology and beyond.
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Affiliation(s)
- David Mayo-Muñoz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Rafael Pinilla-Redondo
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | | | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Genetics Otago, University of Otago, Dunedin, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand.
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand.
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5
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Agapov A, Baker KS, Bedekar P, Bhatia RP, Blower TR, Brockhurst MA, Brown C, Chong CE, Fothergill JL, Graham S, Hall JP, Maestri A, McQuarrie S, Olina A, Pagliara S, Recker M, Richmond A, Shaw SJ, Szczelkun MD, Taylor TB, van Houte S, Went SC, Westra ER, White MF, Wright R. Multi-layered genome defences in bacteria. Curr Opin Microbiol 2024; 78:102436. [PMID: 38368839 DOI: 10.1016/j.mib.2024.102436] [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: 11/14/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/20/2024]
Abstract
Bacteria have evolved a variety of defence mechanisms to protect against mobile genetic elements, including restriction-modification systems and CRISPR-Cas. In recent years, dozens of previously unknown defence systems (DSs) have been discovered. Notably, diverse DSs often coexist within the same genome, and some co-occur at frequencies significantly higher than would be expected by chance, implying potential synergistic interactions. Recent studies have provided evidence of defence mechanisms that enhance or complement one another. Here, we review the interactions between DSs at the mechanistic, regulatory, ecological and evolutionary levels.
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Affiliation(s)
- Aleksei Agapov
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Kate S Baker
- Department of Genetics, University of Cambridge, CB2 3EH, UK
| | - Paritosh Bedekar
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Rama P Bhatia
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Tim R Blower
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Michael A Brockhurst
- Division of Evolution, Infection and Genomics, School of Biological Sciences, University of Manchester, Dover Street, Manchester M13 9PT, UK
| | - Cooper Brown
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | | | - Joanne L Fothergill
- Dept of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, UK
| | - Shirley Graham
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - James Pj Hall
- Dept of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, L69 7ZB, UK
| | - Alice Maestri
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Stuart McQuarrie
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Anna Olina
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | | | - Mario Recker
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Anna Richmond
- ESI, Centre for Ecology and Conservation, University of Exeter, UK
| | - Steven J Shaw
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS6 7YB, UK
| | - Mark D Szczelkun
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS6 7YB, UK
| | - Tiffany B Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | | | - Sam C Went
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Edze R Westra
- ESI, Centre for Ecology and Conservation, University of Exeter, UK.
| | - Malcolm F White
- School of Biology, University of St Andrews, St Andrews KY16 9ST, UK
| | - Rosanna Wright
- Division of Evolution, Infection and Genomics, School of Biological Sciences, University of Manchester, Dover Street, Manchester M13 9PT, UK
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6
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Hu C, Myers MT, Zhou X, Hou Z, Lozen ML, Nam KH, Zhang Y, Ke A. Exploiting activation and inactivation mechanisms in type I-C CRISPR-Cas3 for genome-editing applications. Mol Cell 2024; 84:463-475.e5. [PMID: 38242128 PMCID: PMC10857747 DOI: 10.1016/j.molcel.2023.12.034] [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: 06/20/2023] [Revised: 10/26/2023] [Accepted: 12/21/2023] [Indexed: 01/21/2024]
Abstract
Type I CRISPR-Cas systems utilize the RNA-guided Cascade complex to identify matching DNA targets and the nuclease-helicase Cas3 to degrade them. Among the seven subtypes, type I-C is compact in size and highly active in creating large-sized genome deletions in human cells. Here, we use four cryoelectron microscopy snapshots to define its RNA-guided DNA binding and cleavage mechanisms in high resolution. The non-target DNA strand (NTS) is accommodated by I-C Cascade in a continuous binding groove along the juxtaposed Cas11 subunits. Binding of Cas3 further traps a flexible bulge in NTS, enabling NTS nicking. We identified two anti-CRISPR proteins AcrIC8 and AcrIC9 that strongly inhibit Neisseria lactamica I-C function. Structural analysis showed that AcrIC8 inhibits PAM recognition through allosteric inhibition, whereas AcrIC9 achieves so through direct competition. Both Acrs potently inhibit I-C-mediated genome editing and transcriptional modulation in human cells, providing the first off-switches for type I CRISPR eukaryotic genome engineering.
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Affiliation(s)
- Chunyi Hu
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA; Department of Biological Sciences, Faculty of Science; Department of Biochemistry, Precision Medicine Translational Research Programme (TRP), Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Mason T Myers
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xufei Zhou
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhonggang Hou
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Macy L Lozen
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ki Hyun Nam
- College of General Education, Kookmin University, Seoul 02707, Republic of Korea
| | - Yan Zhang
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, 253 Biotechnology Building, Ithaca, NY 14853, USA.
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7
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Wimmer F, Englert F, Wandera KG, Alkhnbashi O, Collins S, Backofen R, Beisel C. Interrogating two extensively self-targeting Type I CRISPR-Cas systems in Xanthomonas albilineans reveals distinct anti-CRISPR proteins that block DNA degradation. Nucleic Acids Res 2024; 52:769-783. [PMID: 38015466 PMCID: PMC10810201 DOI: 10.1093/nar/gkad1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023] Open
Abstract
CRISPR-Cas systems store fragments of invader DNA as spacers to recognize and clear those same invaders in the future. Spacers can also be acquired from the host's genomic DNA, leading to lethal self-targeting. While self-targeting can be circumvented through different mechanisms, natural examples remain poorly explored. Here, we investigate extensive self-targeting by two CRISPR-Cas systems encoding 24 self-targeting spacers in the plant pathogen Xanthomonas albilineans. We show that the native I-C and I-F1 systems are actively expressed and that CRISPR RNAs are properly processed. When expressed in Escherichia coli, each Cascade complex binds its PAM-flanked DNA target to block transcription, while the addition of Cas3 paired with genome targeting induces cell killing. While exploring how X. albilineans survives self-targeting, we predicted putative anti-CRISPR proteins (Acrs) encoded within the bacterium's genome. Screening of identified candidates with cell-free transcription-translation systems and in E. coli revealed two Acrs, which we named AcrIC11 and AcrIF12Xal, that inhibit the activity of Cas3 but not Cascade of the respective system. While AcrF12Xal is homologous to AcrIF12, AcrIC11 shares sequence and structural homology with the anti-restriction protein KlcA. These findings help explain tolerance of self-targeting through two CRISPR-Cas systems and expand the known suite of DNA degradation-inhibiting Acrs.
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Affiliation(s)
- Franziska Wimmer
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Frank Englert
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Katharina G Wandera
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Omer S Alkhnbashi
- Information and Computer Science Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Intelligent Secure Systems (IRC-ISS), King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
| | - Scott P Collins
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
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8
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Duan N, Hand E, Pheko M, Sharma S, Emiola A. Structure-guided discovery of anti-CRISPR and anti-phage defense proteins. Nat Commun 2024; 15:649. [PMID: 38245560 PMCID: PMC10799925 DOI: 10.1038/s41467-024-45068-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 01/12/2024] [Indexed: 01/22/2024] Open
Abstract
Bacteria use a variety of defense systems to protect themselves from phage infection. In turn, phages have evolved diverse counter-defense measures to overcome host defenses. Here, we use protein structural similarity and gene co-occurrence analyses to screen >66 million viral protein sequences and >330,000 metagenome-assembled genomes for the identification of anti-phage and counter-defense systems. We predict structures for ~300,000 proteins and perform large-scale, pairwise comparison to known anti-CRISPR (Acr) and anti-phage proteins to identify structural homologs that otherwise may not be uncovered using primary sequence search. This way, we identify a Bacteroidota phage Acr protein that inhibits Cas12a, and an Akkermansia muciniphila anti-phage defense protein, termed BxaP. Gene bxaP is found in loci encoding Bacteriophage Exclusion (BREX) and restriction-modification defense systems, but confers immunity independently. Our work highlights the advantage of combining protein structural features and gene co-localization information in studying host-phage interactions.
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Affiliation(s)
- Ning Duan
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Emily Hand
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Mannuku Pheko
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Shikha Sharma
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Akintunde Emiola
- Microbial Therapeutics Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
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9
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Muzyukina P, Shkaruta A, Guzman NM, Andreani J, Borges AL, Bondy-Denomy J, Maikova A, Semenova E, Severinov K, Soutourina O. Identification of an anti-CRISPR protein that inhibits the CRISPR-Cas type I-B system in Clostridioides difficile. mSphere 2023; 8:e0040123. [PMID: 38009936 PMCID: PMC10732046 DOI: 10.1128/msphere.00401-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/10/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Clostridioides difficile is the widespread anaerobic spore-forming bacterium that is a major cause of potentially lethal nosocomial infections associated with antibiotic therapy worldwide. Due to the increase in severe forms associated with a strong inflammatory response and higher recurrence rates, a current imperative is to develop synergistic and alternative treatments for C. difficile infections. In particular, phage therapy is regarded as a potential substitute for existing antimicrobial treatments. However, it faces challenges because C. difficile has highly active CRISPR-Cas immunity, which may be a specific adaptation to phage-rich and highly crowded gut environment. To overcome this defense, C. difficile phages must employ anti-CRISPR mechanisms. Here, we present the first anti-CRISPR protein that inhibits the CRISPR-Cas defense system in this pathogen. Our work offers insights into the interactions between C. difficile and its phages, paving the way for future CRISPR-based applications and development of effective phage therapy strategies combined with the engineering of virulent C. difficile infecting phages.
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Affiliation(s)
- Polina Muzyukina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Anton Shkaruta
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Noemi M. Guzman
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Jessica Andreani
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Adair L. Borges
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Anna Maikova
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ekaterina Semenova
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin Severinov
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Molecular Genetics, Kurchatov National Research Center, Moscow, Russia
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Institut Universitaire de France (IUF), Paris, France
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10
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Li YG, Kishida K, Ogawa-Kishida N, Christie PJ. Ligand-displaying Escherichia coli cells and minicells for programmable delivery of toxic payloads via type IV secretion systems. mBio 2023; 14:e0214323. [PMID: 37772866 PMCID: PMC10653926 DOI: 10.1128/mbio.02143-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/17/2023] [Indexed: 09/30/2023] Open
Abstract
IMPORTANCE The rapid emergence of drug-resistant bacteria and current low rate of antibiotic discovery emphasize the urgent need for alternative antibacterial strategies. We engineered Escherichia coli to conjugatively transfer plasmids to specific E. coli and Pseudomonas aeruginosa recipient cells through the surface display of cognate nanobody/antigen (Nb/Ag) pairs. We further engineered mobilizable plasmids to carry CRISPR/Cas9 systems (pCrispr) for the selective killing of recipient cells harboring CRISPR/Cas9 target sequences. In the assembled programmed delivery system (PDS), Nb-displaying E. coli donors with different conjugation systems and mobilizable pCrispr plasmids suppressed the growth of Ag-displaying recipient cells to significantly greater extents than unpaired recipients. We also showed that anucleate minicells armed with conjugation machines and pCrispr plasmids were highly effective in killing E. coli recipients. Together, our findings suggest that bacteria or minicells armed with PDSs may prove highly effective as an adjunct or alternative to antibiotics for antimicrobial intervention.
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Affiliation(s)
- Yang Grace Li
- Department of Microbiology and Molecular Genetics, McGovern School of Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Kouhei Kishida
- Department of Microbiology and Molecular Genetics, McGovern School of Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Natsumi Ogawa-Kishida
- Department of Microbiology and Molecular Genetics, McGovern School of Medicine, University of Texas Health Science Center, Houston, Texas, USA
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, McGovern School of Medicine, University of Texas Health Science Center, Houston, Texas, USA
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11
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Liu C, Wang R, Li J, Cheng F, Shu X, Zhao H, Xue Q, Yu H, Wu A, Wang L, Hu S, Zhang Y, Yang J, Xiang H, Li M. Widespread RNA-based cas regulation monitors crRNA abundance and anti-CRISPR proteins. Cell Host Microbe 2023; 31:1481-1493.e6. [PMID: 37659410 DOI: 10.1016/j.chom.2023.08.005] [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: 03/23/2023] [Revised: 07/04/2023] [Accepted: 08/09/2023] [Indexed: 09/04/2023]
Abstract
CRISPR RNAs (crRNAs) and Cas proteins work together to provide prokaryotes with adaptive immunity against genetic invaders like bacteriophages and plasmids. However, the coordination of crRNA production and cas expression remains poorly understood. Here, we demonstrate that widespread modulatory mini-CRISPRs encode cas-regulating RNAs (CreRs) that mediate autorepression of type I-B, I-E, and V-A Cas proteins, based on their limited complementarity to cas promoters. This autorepression not only reduces autoimmune risks but also responds to changes in the abundance of canonical crRNAs that compete with CreR for Cas proteins. Furthermore, the CreR-guided autorepression of Cas proteins can be alleviated or even subverted by diverse bacteriophage anti-CRISPR (Acr) proteins that inhibit Cas effectors, which, in turn, promotes the generation of new Cas proteins. Our findings reveal a general RNA-guided autorepression paradigm for diverse Cas effectors, shedding light on the intricate self-coordination of CRISPR-Cas and its transcriptional counterstrategy against Acr proteins.
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Affiliation(s)
- Chao Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Rui Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jie Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Feiyue Cheng
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xian Shu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Huiwei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiong Xue
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Aici Wu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Lingyun Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Plant Protection, Shandong Agricultural University, Taian, Shandong, China
| | - Sushu Hu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yihan Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; School of Life Sciences, Hebei University, Baoding, Hebei, China
| | - Jun Yang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China.
| | - Ming Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China.
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12
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Kang YJ, Kim JH, Lee GH, Ha HJ, Park YH, Hong E, Park HH. The structure of AcrIC9 revealing the putative inhibitory mechanism of AcrIC9 against the type IC CRISPR-Cas system. IUCRJ 2023; 10:624-634. [PMID: 37668219 PMCID: PMC10478522 DOI: 10.1107/s2052252523007236] [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: 04/21/2023] [Accepted: 08/17/2023] [Indexed: 09/06/2023]
Abstract
CRISPR-Cas systems are known to be part of the bacterial adaptive immune system that provides resistance against intruders such as viruses, phages and other mobile genetic elements. To combat this bacterial defense mechanism, phages encode inhibitors called Acrs (anti-CRISPR proteins) that can suppress them. AcrIC9 is the most recently identified member of the AcrIC family that inhibits the type IC CRISPR-Cas system. Here, the crystal structure of AcrIC9 from Rhodobacter capsulatus is reported, which comprises a novel fold made of three central antiparallel β-strands surrounded by three α-helixes, a structure that has not been detected before. It is also shown that AcrIC9 can form a dimer via disulfide bonds generated by the Cys69 residue. Finally, it is revealed that AcrIC9 directly binds to the type IC cascade. Analysis and comparison of its structure with structural homologs indicate that AcrIC9 belongs to DNA-mimic Acrs that directly bind to the cascade complex and hinder the target DNA from binding to the cascade.
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Affiliation(s)
- Yong Jun Kang
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Ju Hyeong Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Gwan Hee Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Young-Hoon Park
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Eunmi Hong
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
- Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
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13
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Li YG, Kishida K, Ogawa-Kishida N, Christie PJ. Ligand-Displaying E. coli Cells and Minicells for Programmable Delivery of Toxic Payloads via Type IV Secretion Systems. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.11.553016. [PMID: 37609324 PMCID: PMC10441419 DOI: 10.1101/2023.08.11.553016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Bacterial type IV secretion systems (T4SSs) are highly versatile macromolecular translocators and offer great potential for deployment as delivery systems for therapeutic intervention. One major T4SS subfamily, the conjugation machines, are well-adapted for delivery of DNA cargoes of interest to other bacteria or eukaryotic cells, but generally exhibit modest transfer frequencies and lack specificity for target cells. Here, we tested the efficacy of a surface-displayed nanobody/antigen (Nb/Ag) pairing system to enhance the conjugative transfer of IncN (pKM101), IncF (F/pOX38), or IncP (RP4) plasmids, or of mobilizable plasmids including those encoding CRISPR/Cas9 systems (pCrispr), to targeted recipient cells. Escherichia coli donors displaying Nb's transferred plasmids to E. coli and Pseudomonas aeruginosa recipients displaying the cognate Ag's at significantly higher frequencies than to recipients lacking Ag's. Nb/Ag pairing functionally substituted for the surface adhesin activities of F-encoded TraN and pKM101-encoded Pep, although not conjugative pili or VirB5-like adhesins. Nb/Ag pairing further elevated the killing effects accompanying delivery of pCrispr plasmids to E. coli and P. aeruginosa transconjugants bearing CRISPR/Cas9 target sequences. Finally, we determined that anucleate E. coli minicells, which are clinically safer delivery vectors than intact cells, transferred self-transmissible and mobilizable plasmids to E. coli and P. aeruginosa cells. Minicell-mediated mobilization of pCrispr plasmids to E. coli recipients elicited significant killing of transconjugants, although Nb/Ag pairing did not enhance conjugation frequencies or killing. Together, our findings establish the potential for deployment of bacteria or minicells as Programmed Delivery Systems (PDSs) for suppression of targeted bacterial species in infection settings. IMPORTANCE The rapid emergence of drug-resistant bacteria and current low rate of antibiotic discovery emphasize an urgent need for alternative antibacterial strategies. We engineered Escherichia coli to conjugatively transfer plasmids to specific E. coli and Pseudomonas aeruginosa recipient cells through surface display of cognate nanobody/antigen (Nb/Ag) pairs. We further engineered mobilizable plasmids to carry CRISPR/Cas9 systems (pCrispr) for selective killing of recipient cells harboring CRISPR/Cas9 target sequences. In the assembled Programmed Delivery System (PDS), Nb-displaying E. coli donors with different conjugation systems and mobilizable pCrispr plasmids suppressed growth of Ag-displaying recipient cells to significantly greater extents than unpaired recipients. We also showed that anucleate minicells armed with conjugation machines and pCrispr plasmids were highly effective in killing of E. coli recipients. Together, our findings suggest that bacteria or minicells armed with PDSs may prove highly effective as an adjunct or alternative to antibiotics for antimicrobial intervention.
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Affiliation(s)
- Yang Grace Li
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, McGovern School of Medicine, Fannin St, Houston, Texas 77030
| | - Kouhei Kishida
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, McGovern School of Medicine, Fannin St, Houston, Texas 77030
- Current address: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aobaku, Sendai, 980-8577, Japan
| | - Natsumi Ogawa-Kishida
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, McGovern School of Medicine, Fannin St, Houston, Texas 77030
- Current address: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aobaku, Sendai, 980-8577, Japan
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, McGovern School of Medicine, Fannin St, Houston, Texas 77030
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14
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Hu C, Myers MT, Zhou X, Hou Z, Lozen ML, Zhang Y, Ke A. Exploiting Activation and Inactivation Mechanisms in Type I-C CRISPR-Cas3 for Genome Editing Applications. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.05.552134. [PMID: 37577534 PMCID: PMC10418205 DOI: 10.1101/2023.08.05.552134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Type I CRISPR-Cas systems utilize the RNA-guided Cascade complex to identify matching DNA targets, and the nuclease-helicase Cas3 to degrade them. Among seven subtypes, Type I-C is compact in size and highly active in creating large-sized genome deletions in human cells. Here we use four cryo-electron microscopy snapshots to define its RNA-guided DNA binding and cleavage mechanisms in high resolution. The non-target DNA strand (NTS) is accommodated by I-C Cascade in a continuous binding groove along the juxtaposed Cas11 subunits. Binding of Cas3 further traps a flexible bulge in NTS, enabling efficient NTS nicking. We identified two anti-CRISPR proteins AcrIC8 and AcrIC9, that strongly inhibit N. lactamica I-C function. Structural analysis showed that AcrIC8 inhibits PAM recognition through direct competition, whereas AcrIC9 achieves so through allosteric inhibition. Both Acrs potently inhibit I-C-mediated genome editing and transcriptional modulation in human cells, providing the first off-switches for controllable Type I CRISPR genome engineering.
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Mayorga-Ramos A, Zúñiga-Miranda J, Carrera-Pacheco SE, Barba-Ostria C, Guamán LP. CRISPR-Cas-Based Antimicrobials: Design, Challenges, and Bacterial Mechanisms of Resistance. ACS Infect Dis 2023; 9:1283-1302. [PMID: 37347230 PMCID: PMC10353011 DOI: 10.1021/acsinfecdis.2c00649] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Indexed: 06/23/2023]
Abstract
The emergence of antibiotic-resistant bacterial strains is a source of public health concern across the globe. As the discovery of new conventional antibiotics has stalled significantly over the past decade, there is an urgency to develop novel approaches to address drug resistance in infectious diseases. The use of a CRISPR-Cas-based system for the precise elimination of targeted bacterial populations holds promise as an innovative approach for new antimicrobial agent design. The CRISPR-Cas targeting system is celebrated for its high versatility and specificity, offering an excellent opportunity to fight antibiotic resistance in pathogens by selectively inactivating genes involved in antibiotic resistance, biofilm formation, pathogenicity, virulence, or bacterial viability. The CRISPR-Cas strategy can enact antimicrobial effects by two approaches: inactivation of chromosomal genes or curing of plasmids encoding antibiotic resistance. In this Review, we provide an overview of the main CRISPR-Cas systems utilized for the creation of these antimicrobials, as well as highlighting promising studies in the field. We also offer a detailed discussion about the most commonly used mechanisms for CRISPR-Cas delivery: bacteriophages, nanoparticles, and conjugative plasmids. Lastly, we address possible mechanisms of interference that should be considered during the intelligent design of these novel approaches.
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Affiliation(s)
- Arianna Mayorga-Ramos
- Centro
de Investigación Biomédica (CENBIO), Facultad de Ciencias
de la Salud Eugenio Espejo, Universidad
UTE, Quito 170527, Ecuador
| | - Johana Zúñiga-Miranda
- Centro
de Investigación Biomédica (CENBIO), Facultad de Ciencias
de la Salud Eugenio Espejo, Universidad
UTE, Quito 170527, Ecuador
| | - Saskya E. Carrera-Pacheco
- Centro
de Investigación Biomédica (CENBIO), Facultad de Ciencias
de la Salud Eugenio Espejo, Universidad
UTE, Quito 170527, Ecuador
| | - Carlos Barba-Ostria
- Escuela
de Medicina, Colegio de Ciencias de la Salud Quito, Universidad San Francisco de Quito USFQ, Quito 170902, Ecuador
| | - Linda P. Guamán
- Centro
de Investigación Biomédica (CENBIO), Facultad de Ciencias
de la Salud Eugenio Espejo, Universidad
UTE, Quito 170527, Ecuador
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Parra-Sánchez Á, Antequera-Zambrano L, Martínez-Navarrete G, Zorrilla-Muñoz V, Paz JL, Alvarado YJ, González-Paz L, Fernández E. Comparative Analysis of CRISPR-Cas Systems in Pseudomonas Genomes. Genes (Basel) 2023; 14:1337. [PMID: 37510242 PMCID: PMC10379622 DOI: 10.3390/genes14071337] [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: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
Pseudomonas is a bacterial genus with some saprophytic species from land and others associated with opportunistic infections in humans and animals. Factors such as pathogenicity or metabolic aspects have been related to CRISPR-Cas, and in silico studies into it have focused more on the clinical and non-environmental setting. This work aimed to perform an in silico analysis of the CRISPR-Cas systems present in Pseudomonas genomes. It analyzed 275 complete genomic sequences of Pseudomonas taken from the NCBI database. CRISPR loci were obtained from CRISPRdb. The genes associated with CRISPR (cas) and CAS proteins, and the origin and diversity of spacer sequences, were identified and compared by BLAST. The presence of self-targeting sequences, PAMs, and the conservation of DRs were visualized using WebLogo 3.6. The CRISPR-like RNA secondary structure prediction was analyzed using RNAFold and MFold. CRISPR structures were identified in 19.6% of Pseudomonas species. In all, 113 typical CRISPR arrays with 18 putative cas were found, as were 2050 spacers, of which 52% showed homology to bacteriophages, 26% to chromosomes, and 22% to plasmids. No potential self-targeting was detected within the CRISPR array. All the found DRs can form thermodynamically stable secondary RNA structures. The comparison of the CRISPR/Cas system can help understand the environmental adaptability of each evolutionary lineage of clinically and environmentally relevant species, providing data support for bacterial typing, traceability, analysis, and exploration of unconventional CRISPR.
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Affiliation(s)
- Ángel Parra-Sánchez
- Genetics and Molecular Biology Laboratory, Biology Department, Faculty of Sciences, University of Zulia, Maracaibo 4001, Venezuela
- Neuroprosthesis and Visual Rehabilitation Laboratory, Bioengineering Institute, University Miguel Hernández of Elche, 03202 Elche, Spain
| | - Laura Antequera-Zambrano
- Genetics and Molecular Biology Laboratory, Biology Department, Faculty of Sciences, University of Zulia, Maracaibo 4001, Venezuela
| | - Gema Martínez-Navarrete
- Neuroprosthesis and Visual Rehabilitation Laboratory, Bioengineering Institute, University Miguel Hernández of Elche, 03202 Elche, Spain
| | - Vanessa Zorrilla-Muñoz
- Bioengineering Institute, University Miguel Hernández of Elche, 03202 Elche, Spain
- University Institute on Gender Studies, University Carlos III of Madrid, Getafe, 28903 Madrid, Spain
| | - José Luis Paz
- Academic Department of Inorganic Chemistry, Faculty of Chemistry and Chemical Engineering, National University of San Marcos, Lima 15081, Peru
| | - Ysaias J Alvarado
- Laboratory of Theoretical and Experimental Biophysical Chemistry (LQBTE), Center for Molecular Biomedicine (CBM), Venezuelan Institute for Scientific Research (IVIC), Maracaibo 4001, Venezuela
| | - Lenin González-Paz
- Genetics and Molecular Biology Laboratory, Biology Department, Faculty of Sciences, University of Zulia, Maracaibo 4001, Venezuela
- Laboratory of Biocomputing (LB), Center for Molecular Biomedicine (CBM), Venezuelan Institute for Scientific Research (IVIC), Maracaibo 4001, Venezuela
| | - Eduardo Fernández
- Neuroprosthesis and Visual Rehabilitation Laboratory, Bioengineering Institute, University Miguel Hernández of Elche, 03202 Elche, Spain
- Biomedical Research Network Center (CIBER-BBN), 28029 Madrid, Spain
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Choudhary N, Tandi D, Verma RK, Yadav VK, Dhingra N, Ghosh T, Choudhary M, Gaur RK, Abdellatif MH, Gacem A, Eltayeb LB, Alqahtani MS, Yadav KK, Jeon BH. A comprehensive appraisal of mechanism of anti-CRISPR proteins: an advanced genome editor to amend the CRISPR gene editing. FRONTIERS IN PLANT SCIENCE 2023; 14:1164461. [PMID: 37426982 PMCID: PMC10328345 DOI: 10.3389/fpls.2023.1164461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 05/23/2023] [Indexed: 07/11/2023]
Abstract
The development of precise and controlled CRISPR-Cas tools has been made possible by the discovery of protein inhibitors of CRISPR-Cas systems, called anti-CRISPRs (Acrs). The Acr protein has the ability to control off-targeted mutations and impede Cas protein-editing operations. Acr can help with selective breeding, which could help plants and animals improve their valuable features. In this review, the Acr protein-based inhibitory mechanisms that have been adopted by several Acrs, such as (a) the interruption of CRISPR-Cas complex assembly, (b) interference with target DNA binding, (c) blocking of target DNA/RNA cleavage, and (d) enzymatic modification or degradation of signalling molecules, were discussed. In addition, this review emphasizes the applications of Acr proteins in the plant research.
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Affiliation(s)
- Nisha Choudhary
- Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Dipty Tandi
- Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Rakesh Kumar Verma
- Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Virendra Kumar Yadav
- Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Naveen Dhingra
- Department of Agriculture, Medi-Caps University, Indore, Madhya Pradesh, India
| | - Tathagata Ghosh
- Department of Arts, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Mahima Choudhary
- Department of Biosciences, School of Liberal Arts and Sciences, Mody University of Science and Technology, Lakshmangarh, Rajasthan, India
| | - Rajarshi K. Gaur
- Department of Biotechnology, Deen Dayal Upadhyaya (D.D.U.) Gorakhpur University, Gorakhpur, Uttar Pradesh, India
| | - Magda H. Abdellatif
- Department of Chemistry, College of Sciences, Taif University, Taif, Saudi Arabia
| | - Amel Gacem
- Department of Physics, Faculty of Sciences, University 20 Août 1955, Skikda, Algeria
| | - Lienda Bashier Eltayeb
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin AbdulAziz University-Al-Kharj, Riyadh, Saudi Arabia
| | - Mohammed S. Alqahtani
- Radiological Sciences Department, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
- Research Center for Advanced Materials Sciences (RCAMS), King Khalid University, Abha, Saudi Arabia
| | - Krishna Kumar Yadav
- Faculty of Science and Technology, Madhyanchal Professional University, Ratibad, India
- Environmental and Atmospheric Sciences Research Group, Scientific Research Center, Al-Ayen University, Thi-Qar, Nasiriyah, Iraq
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, Republic of Korea
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18
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Yang B, Khatri M, Zheng J, Deogun J, Yin Y. Genome mining for anti-CRISPR operons using machine learning. Bioinformatics 2023; 39:btad309. [PMID: 37158576 PMCID: PMC10196667 DOI: 10.1093/bioinformatics/btad309] [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: 01/24/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023] Open
Abstract
MOTIVATION Encoded by (pro-)viruses, anti-CRISPR (Acr) proteins inhibit the CRISPR-Cas immune system of their prokaryotic hosts. As a result, Acr proteins can be employed to develop more controllable CRISPR-Cas genome editing tools. Recent studies revealed that known acr genes often coexist with other acr genes and with phage structural genes within the same operon. For example, we found that 47 of 98 known acr genes (or their homologs) co-exist in the same operons. None of the current Acr prediction tools have considered this important genomic context feature. We have developed a new software tool AOminer to facilitate the improved discovery of new Acrs by fully exploiting the genomic context of known acr genes and their homologs. RESULTS AOminer is the first machine learning based tool focused on the discovery of Acr operons (AOs). A two-state HMM (hidden Markov model) was trained to learn the conserved genomic context of operons that contain known acr genes or their homologs, and the learnt features could distinguish AOs and non-AOs. AOminer allows automated mining for potential AOs from query genomes or operons. AOminer outperformed all existing Acr prediction tools with an accuracy = 0.85. AOminer will facilitate the discovery of novel anti-CRISPR operons. AVAILABILITY AND IMPLEMENTATION The webserver is available at: http://aca.unl.edu/AOminer/AOminer_APP/. The python program is at: https://github.com/boweny920/AOminer.
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Affiliation(s)
- Bowen Yang
- Department of Food Science and Technology, Nebraska Food for Health Center, University of Nebraska—Lincoln, Lincoln, NE 68508, United States
| | - Minal Khatri
- School of Computing, University of Nebraska, Lincoln, NE 68588, United States
| | - Jinfang Zheng
- Department of Food Science and Technology, Nebraska Food for Health Center, University of Nebraska—Lincoln, Lincoln, NE 68508, United States
| | - Jitender Deogun
- School of Computing, University of Nebraska, Lincoln, NE 68588, United States
| | - Yanbin Yin
- Department of Food Science and Technology, Nebraska Food for Health Center, University of Nebraska—Lincoln, Lincoln, NE 68508, United States
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19
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Wang C, Sun Z, Hu Y, Li D, Guo Q, Wang M. A Novel Anti-CRISPR AcrIE9.2 Is Associated with Dissemination of blaKPC Plasmids in Klebsiella pneumoniae Sequence Type 15. Antimicrob Agents Chemother 2023; 67:e0154722. [PMID: 36976005 PMCID: PMC10112057 DOI: 10.1128/aac.01547-22] [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: 11/18/2022] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
Sequence type (ST) 15 has become an emerging clone of carbapenem-resistant Klebsiella pneumoniae in which type I-E* CRISPR-Cas usually exists, indicating that the CRISPR-Cas system may not be able to block the transfer of blaKPC plasmids. The purpose of this study was to explore the mechanisms underlying dissemination of blaKPC plasmids in K. pneumoniae ST15. The type I-E* CRISPR-Cas system was present in 98.0% of 612 nonduplicate K. pneumoniae ST15 strains (88 clinical isolates and 524 from the NCBI database). Twelve ST15 clinical isolates were completely sequenced, and self-targeted protospacers were found on blaKPC plasmids flanked by a protospacer adjacent motif (PAM) of AAT in 11 isolates. The type I-E* CRISPR-Cas system was cloned from a clinical isolate and expressed in Escherichia coli BL21(DE3). In BL21(DE3) harboring the CRISPR system, the transformation efficiency of protospacer-bearing plasmids with a PAM of AAT was reduced by 96.2% compared to the empty vector, indicating that the type I-E* CRISPR-Cas system impeded blaKPC plasmid transfer. BLAST for known anti-CRISPR (Acr) amino acid sequences uncovered a novel AcrIE9-like protein with 40.5% to 44.6% sequence identity with AcrIE9 designated AcrIE9.2, which was present in 90.1% (146 of 162) of ST15 strains carrying both blaKPC and the CRISPR-Cas system. When AcrIE9.2 was cloned and expressed in a ST15 clinical isolate, the conjugation frequency of a CRISPR-targeted blaKPC plasmid was increased from 3.96 × 10-6 to 2.01 × 10-4 compared to the AcrIE9.2 absent strain. In conclusion, AcrIE9.2 may be associated with the dissemination of blaKPC in ST15 by repressing CRISPR-Cas activity.
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Affiliation(s)
- Chuning Wang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
| | - Zhewei Sun
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
| | - Yiyi Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
| | - Dan Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
| | - Qinglan Guo
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
| | - Minggui Wang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Key Laboratory of Clinical Pharmacology of Antibiotics, National Heath Commission of the People’s Republic of China, Shanghai, China
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20
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Forsberg KJ. Anti-CRISPR Discovery: Using Magnets to Find Needles in Haystacks. J Mol Biol 2023; 435:167952. [PMID: 36638909 PMCID: PMC10073268 DOI: 10.1016/j.jmb.2023.167952] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
CRISPR-Cas immune systems in bacteria and archaea protect against viral infection, which has spurred viruses to develop dedicated inhibitors of these systems called anti-CRISPRs (Acrs). Like most host-virus arms races, many diverse examples of these immune and counter-immune proteins are encoded by the genomes of bacteria, archaea, and their viruses. For the case of Acrs, it is almost certain that just a small minority of nature's true diversity has been described. In this review, I discuss the various approaches used to identify these Acrs and speculate on the future for Acr discovery. Because Acrs can determine infection outcomes in nature and regulate CRISPR-Cas activities in applied settings, they have a dual importance to both host-virus conflicts and emerging biotechnologies. Thus, revealing the largely hidden world of Acrs should provide important lessons in microbiology that have the potential to ripple far beyond the field.
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Affiliation(s)
- Kevin J Forsberg
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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21
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Botelho J, Tüffers L, Fuss J, Buchholz F, Utpatel C, Klockgether J, Niemann S, Tümmler B, Schulenburg H. Phylogroup-specific variation shapes the clustering of antimicrobial resistance genes and defence systems across regions of genome plasticity in Pseudomonas aeruginosa. EBioMedicine 2023; 90:104532. [PMID: 36958270 PMCID: PMC10053402 DOI: 10.1016/j.ebiom.2023.104532] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 03/02/2023] [Accepted: 03/07/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Pseudomonas aeruginosa is an opportunistic pathogen consisting of three phylogroups (hereafter named A, B, and C). Here, we assessed phylogroup-specific evolutionary dynamics across available and also new P. aeruginosa genomes. METHODS In this genomic analysis, we first generated new genome assemblies for 18 strains of the major P. aeruginosa clone type (mPact) panel, comprising a phylogenetically diverse collection of clinical and environmental isolates for this species. Thereafter, we combined these new genomes with 1991 publicly available P. aeruginosa genomes for a phylogenomic and comparative analysis. We specifically explored to what extent antimicrobial resistance (AMR) genes, defence systems, and virulence genes vary in their distribution across regions of genome plasticity (RGPs) and "masked" (RGP-free) genomes, and to what extent this variation differs among the phylogroups. FINDINGS We found that members of phylogroup B possess larger genomes, contribute a comparatively larger number of pangenome families, and show lower abundance of CRISPR-Cas systems. Furthermore, AMR and defence systems are pervasive in RGPs and integrative and conjugative/mobilizable elements (ICEs/IMEs) from phylogroups A and B, and the abundance of these cargo genes is often significantly correlated. Moreover, inter- and intra-phylogroup interactions occur at the accessory genome level, suggesting frequent recombination events. Finally, we provide here the mPact panel of diverse P. aeruginosa strains that may serve as a valuable reference for functional analyses. INTERPRETATION Altogether, our results highlight distinct pangenome characteristics of the P. aeruginosa phylogroups, which are possibly influenced by variation in the abundance of CRISPR-Cas systems and are shaped by the differential distribution of other defence systems and AMR genes. FUNDING German Science Foundation, Max-Planck Society, Leibniz ScienceCampus Evolutionary Medicine of the Lung, BMBF program Medical Infection Genomics, Kiel Life Science Postdoc Award.
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Affiliation(s)
- João Botelho
- Antibiotic Resistance Group, Max-Planck Institute for Evolutionary Biology, Plön, Germany; Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany.
| | - Leif Tüffers
- Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany; Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Janina Fuss
- Institute of Clinical Molecular Biology, Christian Albrechts University and University Hospital Schleswig-Holstein, Kiel, Germany
| | - Florian Buchholz
- Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany
| | - Christian Utpatel
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Jens Klockgether
- Clinic for Paediatric Pneumology, Allergology, and Neonatology, Hannover Medical School (MHH), Hannover, Germany
| | - Stefan Niemann
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany; German Center for Infection Research, Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Burkhard Tümmler
- Clinic for Paediatric Pneumology, Allergology, and Neonatology, Hannover Medical School (MHH), Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hannover Medical School, Hannover, Germany
| | - Hinrich Schulenburg
- Antibiotic Resistance Group, Max-Planck Institute for Evolutionary Biology, Plön, Germany; Evolutionary Ecology and Genetics, University of Kiel, Kiel, Germany.
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22
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O'Brien RE, Bravo JPK, Ramos D, Hibshman GN, Wright JT, Taylor DW. Structural snapshots of R-loop formation by a type I-C CRISPR Cascade. Mol Cell 2023; 83:746-758.e5. [PMID: 36805026 PMCID: PMC10026943 DOI: 10.1016/j.molcel.2023.01.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/12/2022] [Accepted: 01/26/2023] [Indexed: 02/18/2023]
Abstract
Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various stages of double-stranded (ds)DNA target capture, revealing mechanisms that underpin PAM recognition and Cascade allosteric activation. We uncover an interesting mechanism of non-target strand (NTS) DNA stabilization via stacking interactions with the "belly" subunits, securing the NTS in place. This "molecular seatbelt" mechanism facilitates efficient R-loop formation and prevents dsDNA reannealing. Additionally, we provide structural insights into how two anti-CRISPR (Acr) proteins utilize distinct strategies to achieve a shared mechanism of type I-C Cascade inhibition by blocking PAM scanning. These observations form a structural basis for directional R-loop formation and reveal how different Acr proteins have converged upon common molecular mechanisms to efficiently shut down CRISPR immunity.
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Affiliation(s)
- Roisin E O'Brien
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX 78712, USA
| | - Jack P K Bravo
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Delisa Ramos
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Grace N Hibshman
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX 78712, USA
| | - Jacquelyn T Wright
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX 78712, USA
| | - David W Taylor
- Interdisciplinary Life Sciences Graduate Programs, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA; LIVESTRONG Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA.
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23
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Goh YX, Wang M, Hou XP, He Y, Ou HY. Analysis of CRISPR-Cas Loci and their Targets in Levilactobacillus brevis. Interdiscip Sci 2023:10.1007/s12539-023-00555-1. [PMID: 36849628 DOI: 10.1007/s12539-023-00555-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 03/01/2023]
Abstract
The CRISPR‒Cas system acts as a bacterial defense mechanism by conferring adaptive immunity and limiting genetic reshuffling. However, under adverse environmental hazards, bacteria can employ their CRISPR‒Cas system to exchange genes that are vital for adaptation and survival. Levilactobacillus brevis is a lactic acid bacterium with great potential for commercial purposes because it can be genetically manipulated to enhance its functionality and nutritional value. Nevertheless, the CRISPR‒Cas system might interfere with the genetic modification process. Additionally, little is known about the CRISPR‒Cas system in this industrially important microorganism. Here, we investigate the prevalence, diversity, and targets of CRISPR‒Cas systems in the genus Levilactobacillus, further focusing on complete genomes of L. brevis. Using the CRISPRCasFinder webserver, we identified 801 putative CRISPR-Cas systems in the genus Levilactobacillus. Further investigation focusing on the complete genomes of L. brevis revealed 54 putative CRISPR-Cas systems. Of these, 46 were orphan CRISPRs, and eight were CRISPR‒Cas systems. The type II-A CRISPR‒Cas system is the most common in Levilactobacillus and L. brevis complete genomes. Analysis of the spacer's target showed that the CRISPR‒Cas systems of L. brevis mainly target the enterococcal plasmids. Comparative analysis of putative CRISPR-Cas loci in Levilactobacillus brevis.
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Affiliation(s)
- Ying-Xian Goh
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, Qingdao, 266100, China.,State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Meng Wang
- State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xiao-Ping Hou
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, Qingdao, 266100, China
| | - Yang He
- State Key Laboratory of Biological Fermentation Engineering of Beer, Tsingtao Brewery Co. Ltd, Qingdao, 266100, China.
| | - Hong-Yu Ou
- State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
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24
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Yin P, Zhang Y, Yang L, Feng Y. Non-canonical inhibition strategies and structural basis of anti-CRISPR proteins targeting type I CRISPR-Cas systems. J Mol Biol 2023; 435:167996. [PMID: 36754343 DOI: 10.1016/j.jmb.2023.167996] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/10/2023] [Accepted: 01/30/2023] [Indexed: 02/08/2023]
Abstract
Mobile genetic elements (MGEs) such as bacteriophages and their host prokaryotes are trapped in an eternal battle against each other. To cope with foreign infection, bacteria and archaea have evolved multiple immune strategies, out of which CRISPR-Cas system is up to now the only discovered adaptive system in prokaryotes. Despite the fact that CRISPR-Cas system provides powerful and delicate protection against MGEs, MGEs have also evolved anti-CRISPR proteins (Acrs) to counteract the CRISPR-Cas immune defenses. To date, 46 families of Acrs targeting type I CRISPR-Cas system have been characterized, out of which structure information of 21 families have provided insights on their inhibition strategies. Here, we review the non-canonical inhibition strategies adopted by Acrs targeting type I CRISPR-Cas systems based on their structure information by incorporating the most recent advances in this field, and discuss our current understanding and future perspectives. The delicate interplay between type I CRISPR-Cas systems and their Acrs provides us with important insights into the ongoing fierce arms race between prokaryotic hosts and their predators.
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Affiliation(s)
- Peipei Yin
- Jiangxi Provincial Key Laboratory of Natural Active Pharmaceutical Constituents, College of Chemical and Biological Engineering, Yichun University, Yichun 336000, China
| | - Yi Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lingguang Yang
- Jiangxi Provincial Key Laboratory of Natural Active Pharmaceutical Constituents, College of Chemical and Biological Engineering, Yichun University, Yichun 336000, China
| | - Yue Feng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing Key Laboratory of Bioprocess, State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
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25
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Puxty RJ, Millard AD. Functional ecology of bacteriophages in the environment. Curr Opin Microbiol 2023; 71:102245. [PMID: 36512900 DOI: 10.1016/j.mib.2022.102245] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/12/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
Bacteriophages are as ubiquitous as their bacterial hosts and often more abundant. Understanding how bacteriophages control their bacterial host populations requires a number of different approaches. Bacteriophages can control bacterial populations through lysis, drive evolution of bacterial immunity systems through infection, provide a conduit for horizontal gene transfer and alter host metabolism by carriage of auxiliary metabolic genes. Understanding and quantifying how bacteriophages drive these processes, requires both technological developments to take measurements in situ, and laboratory-based studies to understand mechanisms. Technological advances have allowed quantification of the number of infected cells in situ, revealing far-lower levels than expected. Understanding how observations in laboratory conditions relate to what occurs in the environment, and experimental confirmation of the predicted function of phage genes from observations in environmental omics data, remains challenging.
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Affiliation(s)
- Richard J Puxty
- University of Warwick, School of Life Sciences, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
| | - Andrew D Millard
- University of Leicester, Dept of Genetics and Genome Biology, University Road, Leicester, United Kingdom.
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26
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Ecology and evolution of phages encoding anti-CRISPR proteins. J Mol Biol 2023; 435:167974. [PMID: 36690071 DOI: 10.1016/j.jmb.2023.167974] [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: 10/27/2022] [Revised: 01/11/2023] [Accepted: 01/14/2023] [Indexed: 01/21/2023]
Abstract
CRISPR-Cas are prokaryotic defence systems that provide protection against invasion by mobile genetic elements (MGE), including bacteriophages. MGE can overcome CRISPR-Cas defences by encoding anti-CRISPR (Acr) proteins. These proteins are produced in the early stages of the infection and inhibit the CRISPR-Cas machinery to allow phage replication. While research on Acr has mainly focused on their discovery, structure and mode of action, and their applications in biotechnology, the impact of Acr on the ecology of MGE as well as on the coevolution with their bacterial hosts only begins to be unravelled. In this review, we summarise our current understanding on the distribution of anti-CRISPR genes in MGE, the ecology of phages encoding Acr, and their coevolution with bacterial defence mechanisms. We highlight the need to use more diverse and complex experimental models to better understand the impact of anti-CRISPR in MGE-host interactions.
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27
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Strathdee SA, Hatfull GF, Mutalik VK, Schooley RT. Phage therapy: From biological mechanisms to future directions. Cell 2023; 186:17-31. [PMID: 36608652 PMCID: PMC9827498 DOI: 10.1016/j.cell.2022.11.017] [Citation(s) in RCA: 140] [Impact Index Per Article: 140.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/01/2022] [Accepted: 11/16/2022] [Indexed: 01/07/2023]
Abstract
Increasing antimicrobial resistance rates have revitalized bacteriophage (phage) research, the natural predators of bacteria discovered over 100 years ago. In order to use phages therapeutically, they should (1) preferably be lytic, (2) kill the bacterial host efficiently, and (3) be fully characterized to exclude side effects. Developing therapeutic phages takes a coordinated effort of multiple stakeholders. Herein, we review the state of the art in phage therapy, covering biological mechanisms, clinical applications, remaining challenges, and future directions involving naturally occurring and genetically modified or synthetic phages.
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Affiliation(s)
- Steffanie A Strathdee
- Center for Innovative Phage Applications and Therapeutics, Division of Infectious Disease and Global Public Health, University of California, San Diego, La Jolla, CA 92093-0507, USA.
| | - Graham F Hatfull
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Vivek K Mutalik
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Robert T Schooley
- Center for Innovative Phage Applications and Therapeutics, Division of Infectious Disease and Global Public Health, University of California, San Diego, La Jolla, CA 92093-0507, USA
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28
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Botelho J, Cazares A, Schulenburg H. The ESKAPE mobilome contributes to the spread of antimicrobial resistance and CRISPR-mediated conflict between mobile genetic elements. Nucleic Acids Res 2023; 51:236-252. [PMID: 36610752 PMCID: PMC9841420 DOI: 10.1093/nar/gkac1220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 01/09/2023] Open
Abstract
Mobile genetic elements (MGEs) mediate the shuffling of genes among organisms. They contribute to the spread of virulence and antibiotic resistance (AMR) genes in human pathogens, such as the particularly problematic group of ESKAPE pathogens. Here, we performed the first systematic analysis of MGEs, including plasmids, prophages, and integrative and conjugative/mobilizable elements (ICEs/IMEs), across all ESKAPE pathogens. We found that different MGE types are asymmetrically distributed across these pathogens, and that most horizontal gene transfer (HGT) events are restricted by phylum or genus. We show that the MGEs proteome is involved in diverse functional processes and distinguish widespread proteins within the ESKAPE context. Moreover, anti-CRISPRs and AMR genes are overrepresented in the ESKAPE mobilome. Our results also underscore species-specific trends shaping the number of MGEs, AMR, and virulence genes across pairs of conspecific ESKAPE genomes with and without CRISPR-Cas systems. Finally, we observed that CRISPR spacers found on prophages, ICEs/IMEs, and plasmids have different targeting biases: while plasmid and prophage CRISPRs almost exclusively target other plasmids and prophages, respectively, ICEs/IMEs CRISPRs preferentially target prophages. Overall, our study highlights the general importance of the ESKAPE mobilome in contributing to the spread of AMR and mediating conflict among MGEs.
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Affiliation(s)
- João Botelho
- To whom correspondence should be addressed. Tel: +49 431 880 4143;
| | - Adrian Cazares
- EMBL’s European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK,Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Hinrich Schulenburg
- Antibiotic Resistance Evolution Group, Max Planck Institute for Evolutionary Biology, Plön, Germany,Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian Albrechts University, Kiel, Germany
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29
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Kudryavtseva AA, Cséfalvay E, Gnuchikh EY, Yanovskaya DD, Skutel MA, Isaev AB, Bazhenov SV, Utkina AA, Manukhov IV. Broadness and specificity: ArdB, ArdA, and Ocr against various restriction-modification systems. Front Microbiol 2023; 14:1133144. [PMID: 37138625 PMCID: PMC10149784 DOI: 10.3389/fmicb.2023.1133144] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 03/10/2023] [Indexed: 05/05/2023] Open
Abstract
ArdB, ArdA, and Ocr proteins inhibit the endonuclease activity of the type I restriction-modification enzymes (RMI). In this study, we evaluated the ability of ArdB, ArdA, and Ocr to inhibit different subtypes of Escherichia coli RMI systems (IA, IB, and IC) as well as two Bacillus licheniformis RMI systems. Furthermore we explored, the antirestriction activity of ArdA, ArdB, and Ocr against a type III restriction-modification system (RMIII) EcoPI and BREX. We found that DNA-mimic proteins, ArdA and Ocr exhibit different inhibition activity, depending on which RM system tested. This effect might be linked to the DNA mimicry nature of these proteins. In theory, DNA-mimic might competitively inhibit any DNA-binding proteins; however, the efficiency of inhibition depend on the ability to imitate the recognition site in DNA or its preferred conformation. In contrast, ArdB protein with an undescribed mechanism of action, demonstrated greater versatility against various RMI systems and provided similar antirestriction efficiency regardless of the recognition site. However, ArdB protein could not affect restriction systems that are radically different from the RMI such as BREX or RMIII. Thus, we assume that the structure of DNA-mimic proteins allows for selective inhibition of any DNA-binding proteins depending on the recognition site. In contrast, ArdB-like proteins inhibit RMI systems independently of the DNA recognition site.
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Affiliation(s)
- Anna A. Kudryavtseva
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- *Correspondence: Anna A. Kudryavtseva
| | - Eva Cséfalvay
- Laboratory of Structural Biology and Bioinformatics, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nové Hrady, Czechia
| | - Evgeniy Yu Gnuchikh
- Kurchatov Genomic Center, National Research Center Kurchatov Institute, Moscow, Russia
| | - Darya D. Yanovskaya
- Center of Cellular and Molecular Biology, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Mikhail A. Skutel
- Center of Cellular and Molecular Biology, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Artem B. Isaev
- Center of Cellular and Molecular Biology, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Sergey V. Bazhenov
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Laboratory for Microbiology, BIOTECH University, Moscow, Russia
- Faculty of Physics, HSE University, Moscow, Russia
| | - Anna A. Utkina
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ilya V. Manukhov
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- Laboratory for Microbiology, BIOTECH University, Moscow, Russia
- Faculty of Physics, HSE University, Moscow, Russia
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30
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de Oliveira HL, Dias GM, Neves BC. Genome sequence of Pseudomonas aeruginosa PA1-Petro—A role model of environmental adaptation and a potential biotechnological tool. Heliyon 2022; 8:e11566. [DOI: 10.1016/j.heliyon.2022.e11566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/12/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
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31
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Qin S, Liu Y, Chen Y, Hu J, Xiao W, Tang X, Li G, Lin P, Pu Q, Wu Q, Zhou C, Wang B, Gao P, Wang Z, Yan A, Nadeem K, Xia Z, Wu M. Engineered Bacteriophages Containing Anti-CRISPR Suppress Infection of Antibiotic-Resistant P. aeruginosa. Microbiol Spectr 2022; 10:e0160222. [PMID: 35972246 PMCID: PMC9602763 DOI: 10.1128/spectrum.01602-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/05/2022] [Indexed: 12/31/2022] Open
Abstract
The therapeutic use of bacteriophages (phages) provides great promise for treating multidrug-resistant (MDR) bacterial infections. However, an incomplete understanding of the interactions between phages and bacteria has negatively impacted the application of phage therapy. Here, we explored engineered anti-CRISPR (Acr) gene-containing phages (EATPs, eat Pseudomonas) by introducing Type I anti-CRISPR (AcrIF1, AcrIF2, and AcrIF3) genes into the P. aeruginosa bacteriophage DMS3/DMS3m to render the potential for blocking P. aeruginosa replication and infection. In order to achieve effective antibacterial activities along with high safety against clinically isolated MDR P. aeruginosa through an anti-CRISPR immunity mechanism in vitro and in vivo, the inhibitory concentration for EATPs was 1 × 108 PFU/mL with a multiplicity of infection value of 0.2. In addition, the EATPs significantly suppressed the antibiotic resistance caused by a highly antibiotic-resistant PA14 infection. Collectively, these findings provide evidence that engineered phages may be an alternative, viable approach by which to treat patients with an intractable bacterial infection, especially an infection by clinically MDR bacteria that are unresponsive to conventional antibiotic therapy. IMPORTANCE Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic Gram-negative bacterium that causes severe infection in immune-weakened individuals, especially patients with cystic fibrosis, burn wounds, cancer, or chronic obstructive pulmonary disease (COPD). Treating P. aeruginosa infection with conventional antibiotics is difficult due to its intrinsic multidrug resistance. Engineered bacteriophage therapeutics, acting as highly viable alternative treatments of multidrug-resistant (MDR) bacterial infections, have great potential to break through the evolutionary constraints of bacteriophages to create next-generation antimicrobials. Here, we found that engineered anti-CRISPR (Acr) gene-containing phages (EATPs, eat Pseudomonas) display effective antibacterial activities along with high safety against clinically isolated MDR P. aeruginosa through an anti-CRISPR immunity mechanism in vitro and in vivo. EATPs also significantly suppressed the antibiotic resistance caused by a highly antibiotic-resistant PA14 infection, which may provide novel insight toward developing bacteriophages to treat patients with intractable bacterial infections, especially infections by clinically MDR bacteria that are unresponsive to conventional antibiotic therapy.
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Affiliation(s)
- Shugang Qin
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Yongan Liu
- Department of Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuting Chen
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Jinrong Hu
- West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wen Xiao
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoshan Tang
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Guohong Li
- Department of Critical Care Medicine, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Ping Lin
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Qinqin Pu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Qun Wu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Chuanmin Zhou
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Biao Wang
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Pan Gao
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Zhihan Wang
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Aixin Yan
- School of Biological Sciences, The University of Hong Kong, Shatin, Hong Kong SAR
| | - Khan Nadeem
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Zhenwei Xia
- Department of Pediatrics, Ruijin Hospital affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Min Wu
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
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32
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Haudiquet M, de Sousa JM, Touchon M, Rocha EPC. Selfish, promiscuous and sometimes useful: how mobile genetic elements drive horizontal gene transfer in microbial populations. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210234. [PMID: 35989606 PMCID: PMC9393566 DOI: 10.1098/rstb.2021.0234] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Horizontal gene transfer (HGT) drives microbial adaptation but is often under the control of mobile genetic elements (MGEs) whose interests are not necessarily aligned with those of their hosts. In general, transfer is costly to the donor cell while potentially beneficial to the recipients. The diversity and plasticity of cell–MGEs interactions, and those among MGEs, result in complex evolutionary processes where the source, or even the existence of selection for maintaining a function in the genome, is often unclear. For example, MGE-driven HGT depends on cell envelope structures and defense systems, but many of these are transferred by MGEs themselves. MGEs can spur periods of intense gene transfer by increasing their own rates of horizontal transmission upon communicating, eavesdropping, or sensing the environment and the host physiology. This may result in high-frequency transfer of host genes unrelated to the MGE. Here, we review how MGEs drive HGT and how their transfer mechanisms, selective pressures and genomic traits affect gene flow, and therefore adaptation, in microbial populations. The encoding of many adaptive niche-defining microbial traits in MGEs means that intragenomic conflicts and alliances between cells and their MGEs are key to microbial functional diversification. This article is part of a discussion meeting issue ‘Genomic population structures of microbial pathogens’.
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Affiliation(s)
- Matthieu Haudiquet
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Jorge Moura de Sousa
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Marie Touchon
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
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33
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Ilyina TS. Adaptive Immunity Systems of Bacteria: Association with Self-Synthesizing Transposons, Polyfunctionality. MOLECULAR GENETICS, MICROBIOLOGY AND VIROLOGY 2022. [DOI: 10.3103/s0891416822030065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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34
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Shehreen S, Birkholz N, Fineran P, Brown C. Widespread repression of anti-CRISPR production by anti-CRISPR-associated proteins. Nucleic Acids Res 2022; 50:8615-8625. [PMID: 35947749 PMCID: PMC9410906 DOI: 10.1093/nar/gkac674] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/06/2022] [Accepted: 07/25/2022] [Indexed: 12/24/2022] Open
Abstract
Many bacteria use CRISPR-Cas systems to defend against invasive mobile genetic elements (MGEs). In response, MGEs have developed strategies to resist CRISPR-Cas, including the use of anti-CRISPR (Acr) proteins. Known acr genes may be followed in an operon by a putative regulatory Acr-associated gene (aca), suggesting the importance of regulation. Although ten families of helix-turn-helix (HTH) motif containing Aca proteins have been identified (Aca1-10), only three have been tested and shown to be transcriptional repressors of acr-aca expression. The AcrIIA1 protein (a Cas9 inhibitor) also contains a functionally similar HTH containing repressor domain. Here, we identified and analysed Aca and AcrIIA1 homologs across all bacterial genomes. Using HMM models we found aca-like genes are widely distributed in bacteria, both with and without known acr genes. The putative promoter regions of acr-aca operons were analysed and members of each family of bacterial Aca tested for regulatory function. For each Aca family, we predicted a conserved inverted repeat binding site within a core promoter. Promoters containing these sites directed reporter expression in E. coli and were repressed by the cognate Aca protein. These data demonstrate that acr repression by Aca proteins is widely conserved in nature.
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Affiliation(s)
- Saadlee Shehreen
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin 9054, New Zealand,Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand,Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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35
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Lee SY, Birkholz N, Fineran PC, Park HH. Molecular basis of anti-CRISPR operon repression by Aca10. Nucleic Acids Res 2022; 50:8919-8928. [PMID: 35920325 PMCID: PMC9410881 DOI: 10.1093/nar/gkac656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/05/2022] [Accepted: 07/21/2022] [Indexed: 01/11/2023] Open
Abstract
CRISPR-Cas systems are bacterial defense systems for fighting against invaders such as bacteriophages and mobile genetic elements. To escape destruction by these bacterial immune systems, phages have co-evolved multiple anti-CRISPR (Acr) proteins, which inhibit CRISPR-Cas function. Many acr genes form an operon with genes encoding transcriptional regulators, called anti-CRISPR-associated (Aca) proteins. Aca10 is the most recently discovered Aca family that is encoded within an operon containing acrIC7 and acrIC6 in Pseudomonas citronellolis. Here, we report the high-resolution crystal structure of an Aca10 protein to unveil the molecular basis of transcriptional repressor role of Aca10 in the acrIC7-acrIC6-aca10 operon. We identified that Aca10 forms a dimer in solution, which is critical for binding specific DNA. We also showed that Aca10 directly recognizes a 21 bp palindromic sequence in the promoter of the acr operon. Finally, we revealed that R44 of Aca10 is a critical residue involved in the DNA binding, which likely results in a high degree of DNA bending.
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Affiliation(s)
- So Yeon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
| | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.,Department of Global Innovative Drugs, Graduate School of Chung-Ang University, Seoul 06974, Republic of Korea
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36
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Kang YJ, Park HH. High-resolution crystal structure of the anti-CRISPR protein AcrIC5. Biochem Biophys Res Commun 2022; 625:102-108. [DOI: 10.1016/j.bbrc.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
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37
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The resurgence of phage-based therapy in the era of increasing antibiotic resistance: from research progress to challenges and prospects. Microbiol Res 2022; 264:127155. [DOI: 10.1016/j.micres.2022.127155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 12/23/2022]
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38
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Pinilla-Redondo R, Russel J, Mayo-Muñoz D, Shah SA, Garrett RA, Nesme J, Madsen JS, Fineran PC, Sørensen SJ. CRISPR-Cas systems are widespread accessory elements across bacterial and archaeal plasmids. Nucleic Acids Res 2022; 50:4315-4328. [PMID: 34606604 DOI: 10.1093/nar/gkab859/40506127/gkab859.pdf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/08/2021] [Accepted: 10/02/2021] [Indexed: 05/27/2023] Open
Abstract
Many prokaryotes encode CRISPR-Cas systems as immune protection against mobile genetic elements (MGEs), yet a number of MGEs also harbor CRISPR-Cas components. With a few exceptions, CRISPR-Cas loci encoded on MGEs are uncharted and a comprehensive analysis of their distribution, prevalence, diversity, and function is lacking. Here, we systematically investigated CRISPR-Cas loci across the largest curated collection of natural bacterial and archaeal plasmids. CRISPR-Cas loci are widely but heterogeneously distributed across plasmids and, in comparison to host chromosomes, their mean prevalence per Mbp is higher and their distribution is distinct. Furthermore, the spacer content of plasmid CRISPRs exhibits a strong targeting bias towards other plasmids, while chromosomal arrays are enriched with virus-targeting spacers. These contrasting targeting preferences highlight the genetic independence of plasmids and suggest a major role for mediating plasmid-plasmid conflicts. Altogether, CRISPR-Cas are frequent accessory components of many plasmids, which is an overlooked phenomenon that possibly facilitates their dissemination across microbiomes.
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Affiliation(s)
- Rafael Pinilla-Redondo
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
- Department of Technological Educations, University College Copenhagen, Sigurdsgade 26, 2200 Copenhagen, Denmark
| | - Jakob Russel
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - David Mayo-Muñoz
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Shiraz A Shah
- Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Ledreborg Alle 34, 2820 Gentofte, Denmark
| | - Roger A Garrett
- Danish Archaea Centre, Department of Biology, University of Copenhagen, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Joseph Nesme
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Jonas S Madsen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bio-Protection Research Centre, University of Otago, Dunedin, New Zealand
| | - Søren J Sørensen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
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39
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Pursey E, Dimitriu T, Paganelli FL, Westra ER, van Houte S. CRISPR-Cas is associated with fewer antibiotic resistance genes in bacterial pathogens. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200464. [PMID: 34839714 PMCID: PMC8628084 DOI: 10.1098/rstb.2020.0464] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/21/2021] [Indexed: 01/19/2023] Open
Abstract
The acquisition of antibiotic resistance (ABR) genes via horizontal gene transfer (HGT) is a key driver of the rise in multidrug resistance amongst bacterial pathogens. Bacterial defence systems per definition restrict the influx of foreign genetic material, and may therefore limit the acquisition of ABR. CRISPR-Cas adaptive immune systems are one of the most prevalent defences in bacteria, found in roughly half of bacterial genomes, but it has remained unclear if and how much they contribute to restricting the spread of ABR. We analysed approximately 40 000 whole genomes comprising the full RefSeq dataset for 11 species of clinically important genera of human pathogens, including Enterococcus, Staphylococcus, Acinetobacter and Pseudomonas. We modelled the association between CRISPR-Cas and indicators of HGT, and found that pathogens with a CRISPR-Cas system were less likely to carry ABR genes than those lacking this defence system. Analysis of the mobile genetic elements (MGEs) targeted by CRISPR-Cas supports a model where this host defence system blocks important vectors of ABR. These results suggest a potential 'immunocompromised' state for multidrug-resistant strains that may be exploited in tailored interventions that rely on MGEs, such as phages or phagemids, to treat infections caused by bacterial pathogens. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
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Affiliation(s)
- Elizabeth Pursey
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Tatiana Dimitriu
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Fernanda L. Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Edze R. Westra
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Stineke van Houte
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
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40
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Rocha EPC, Bikard D. Microbial defenses against mobile genetic elements and viruses: Who defends whom from what? PLoS Biol 2022; 20:e3001514. [PMID: 35025885 PMCID: PMC8791490 DOI: 10.1371/journal.pbio.3001514] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/26/2022] [Indexed: 12/27/2022] Open
Abstract
Prokaryotes have numerous mobile genetic elements (MGEs) that mediate horizontal gene transfer (HGT) between cells. These elements can be costly, even deadly, and cells use numerous defense systems to filter, control, or inactivate them. Recent studies have shown that prophages, conjugative elements, their parasites (phage satellites and mobilizable elements), and other poorly described MGEs encode defense systems homologous to those of bacteria. These constitute a significant fraction of the repertoire of cellular defense genes. As components of MGEs, these defense systems have presumably evolved to provide them, not the cell, adaptive functions. While the interests of the host and MGEs are aligned when they face a common threat such as an infection by a virulent phage, defensive functions carried by MGEs might also play more selfish roles to fend off other antagonistic MGEs or to ensure their maintenance in the cell. MGEs are eventually lost from the surviving host genomes by mutational processes and their defense systems can be co-opted when they provide an advantage to the cell. The abundance of defense systems in MGEs thus sheds new light on the role, effect, and fate of the so-called "cellular defense systems," whereby they are not only merely microbial defensive weapons in a 2-partner arms race, but also tools of intragenomic conflict between multiple genetic elements with divergent interests that shape cell fate and gene flow at the population level.
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Affiliation(s)
- Eduardo P. C. Rocha
- Institut Pasteur, Université de Paris, CNRS UMR3525, Microbial Evolutionary Genomics, Paris, France
| | - David Bikard
- Institut Pasteur, Université de Paris, Synthetic Biology, Department of Microbiology, Paris, France
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41
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Picton DM, Luyten YA, Morgan RD, Nelson A, Smith DL, Dryden DTF, Hinton JCD, Blower TR. The phage defence island of a multidrug resistant plasmid uses both BREX and type IV restriction for complementary protection from viruses. Nucleic Acids Res 2021; 49:11257-11273. [PMID: 34657954 PMCID: PMC8565348 DOI: 10.1093/nar/gkab906] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 01/21/2023] Open
Abstract
Bacteria have evolved a multitude of systems to prevent invasion by bacteriophages and other mobile genetic elements. Comparative genomics suggests that genes encoding bacterial defence mechanisms are often clustered in 'defence islands', providing a concerted level of protection against a wider range of attackers. However, there is a comparative paucity of information on functional interplay between multiple defence systems. Here, we have functionally characterised a defence island from a multidrug resistant plasmid of the emerging pathogen Escherichia fergusonii. Using a suite of thirty environmentally-isolated coliphages, we demonstrate multi-layered and robust phage protection provided by a plasmid-encoded defence island that expresses both a type I BREX system and the novel GmrSD-family type IV DNA modification-dependent restriction enzyme, BrxU. We present the structure of BrxU to 2.12 Å, the first structure of the GmrSD family of enzymes, and show that BrxU can utilise all common nucleotides and a wide selection of metals to cleave a range of modified DNAs. Additionally, BrxU undergoes a multi-step reaction cycle instigated by an unexpected ATP-dependent shift from an intertwined dimer to monomers. This direct evidence that bacterial defence islands can mediate complementary layers of phage protection enhances our understanding of the ever-expanding nature of phage-bacterial interactions.
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Affiliation(s)
- David M Picton
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Yvette A Luyten
- New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | | | - Andrew Nelson
- Department of Applied Sciences, University of Northumbria, Newcastle Upon Tyne NE1 8ST, UK
| | - Darren L Smith
- Department of Applied Sciences, University of Northumbria, Newcastle Upon Tyne NE1 8ST, UK
| | - David T F Dryden
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Jay C D Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Tim R Blower
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
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42
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Pinilla-Redondo R, Russel J, Mayo-Muñoz D, Shah SA, Garrett RA, Nesme J, Madsen JS, Fineran PC, Sørensen SJ. CRISPR-Cas systems are widespread accessory elements across bacterial and archaeal plasmids. Nucleic Acids Res 2021; 50:4315-4328. [PMID: 34606604 PMCID: PMC9071438 DOI: 10.1093/nar/gkab859] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/08/2021] [Accepted: 10/02/2021] [Indexed: 12/12/2022] Open
Abstract
Many prokaryotes encode CRISPR-Cas systems as immune protection against mobile genetic elements (MGEs), yet a number of MGEs also harbor CRISPR-Cas components. With a few exceptions, CRISPR-Cas loci encoded on MGEs are uncharted and a comprehensive analysis of their distribution, prevalence, diversity, and function is lacking. Here, we systematically investigated CRISPR-Cas loci across the largest curated collection of natural bacterial and archaeal plasmids. CRISPR-Cas loci are widely but heterogeneously distributed across plasmids and, in comparison to host chromosomes, their mean prevalence per Mbp is higher and their distribution is distinct. Furthermore, the spacer content of plasmid CRISPRs exhibits a strong targeting bias towards other plasmids, while chromosomal arrays are enriched with virus-targeting spacers. These contrasting targeting preferences highlight the genetic independence of plasmids and suggest a major role for mediating plasmid-plasmid conflicts. Altogether, CRISPR-Cas are frequent accessory components of many plasmids, which is an overlooked phenomenon that possibly facilitates their dissemination across microbiomes.
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Affiliation(s)
- Rafael Pinilla-Redondo
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.,Department of Technological Educations, University College Copenhagen, Sigurdsgade 26, 2200 Copenhagen, Denmark
| | - Jakob Russel
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - David Mayo-Muñoz
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.,Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Shiraz A Shah
- Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Ledreborg Alle 34, 2820 Gentofte, Denmark
| | - Roger A Garrett
- Danish Archaea Centre, Department of Biology, University of Copenhagen, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Joseph Nesme
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Jonas S Madsen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Bio-Protection Research Centre, University of Otago, Dunedin, New Zealand
| | - Søren J Sørensen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
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43
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Baliga P, Shekar M, Tg P, Sk G. Investigation into the prevalent CRISPR-Cas systems among the Aeromonas genus. J Basic Microbiol 2021; 61:874-882. [PMID: 34486151 DOI: 10.1002/jobm.202100234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/12/2021] [Accepted: 08/21/2021] [Indexed: 01/15/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) is a prokaryotic adaptive immune system that checks invasion by mobile genetic elements through nuclease targeting. In this study, we investigated the occurrence, diversity, and features of the CRISPR system in the genus Aeromonas using bioinformatics tools. Only 13 out of 122 complete genomes (10.66%) of the genus Aeromonas from the NCBI GenBank database harbored the CRISPR system. The Type I-F system was the most prevalent CRISPR system among the Aeromonads, followed by the Type I-E system. Only one strain harbored a Type I-C CRISPR system. Among the Aeromonads, Aeromonas caviae (22.7%) and Aeromonas veronii (20%) had a higher prevalence rate of the complete CRISPR system. The analysis of direct repeat (DR) sequences showed that all could form stable RNA secondary structures. A phylogenetic tree generated for the Cas1 protein classified CRISPR subtypes into three distinct clusters. Among the 748 spacers investigated, 41.98% and 17.25% showed perfect homology to phage and plasmid sequences, respectively. Some arrays had duplicated spacers. The CRISPR loci are closely linked to antibiotic resistance genes in most strains. Collectively, our results would contribute to research on antibiotic resistance in the Aeromonas group, and provide new insights into the diversity and evolution of the CRISPR-Cas system.
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Affiliation(s)
- Pallavi Baliga
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Malathi Shekar
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Puneeth Tg
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Girisha Sk
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
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44
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Jia N, Patel DJ. Structure-based functional mechanisms and biotechnology applications of anti-CRISPR proteins. Nat Rev Mol Cell Biol 2021; 22:563-579. [PMID: 34089013 DOI: 10.1038/s41580-021-00371-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2021] [Indexed: 02/03/2023]
Abstract
CRISPR loci and Cas proteins provide adaptive immunity in prokaryotes against invading bacteriophages and plasmids. In response, bacteriophages have evolved a broad spectrum of anti-CRISPR proteins (anti-CRISPRs) to counteract and overcome this immunity pathway. Numerous anti-CRISPRs have been identified to date, which suppress single-subunit Cas effectors (in CRISPR class 2, type II, V and VI systems) and multisubunit Cascade effectors (in CRISPR class 1, type I and III systems). Crystallography and cryo-electron microscopy structural studies of anti-CRISPRs bound to effector complexes, complemented by functional experiments in vitro and in vivo, have identified four major CRISPR-Cas suppression mechanisms: inhibition of CRISPR-Cas complex assembly, blocking of target binding, prevention of target cleavage, and degradation of cyclic oligonucleotide signalling molecules. In this Review, we discuss novel mechanistic insights into anti-CRISPR function that have emerged from X-ray crystallography and cryo-electron microscopy studies, and how these structures in combination with function studies provide valuable tools for the ever-growing CRISPR-Cas biotechnology toolbox, to be used for precise and robust genome editing and other applications.
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Affiliation(s)
- Ning Jia
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA. .,Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China.
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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45
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Usher B, Birkholz N, Beck IN, Fagerlund RD, Jackson SA, Fineran PC, Blower TR. Crystal structure of the anti-CRISPR repressor Aca2. J Struct Biol 2021; 213:107752. [PMID: 34116143 PMCID: PMC8434428 DOI: 10.1016/j.jsb.2021.107752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/26/2021] [Accepted: 06/06/2021] [Indexed: 11/16/2022]
Abstract
The crystal structure of the anti-CRISPR repressor Aca2 has been solved to 1.34 Å. Aca2 contains a new dimerization domain for HTH transcriptional regulators. Aca2-like regulators are found encoded in diverse biological contexts.
Bacteria use adaptive CRISPR-Cas immune mechanisms to protect from invasion by bacteriophages and other mobile genetic elements. In response, bacteriophages and mobile genetic elements have co-evolved anti-CRISPR proteins to inhibit the bacterial defense. We and others have previously shown that anti-CRISPR associated (Aca) proteins can regulate this anti-CRISPR counter-attack. Here, we report the first structure of an Aca protein, the Aca2 DNA-binding transcriptional autorepressor from Pectobacterium carotovorum bacteriophage ZF40, determined to 1.34 Å. Aca2 presents a conserved N-terminal helix-turn-helix DNA-binding domain and a previously uncharacterized C-terminal dimerization domain. Dimerization positions the Aca2 recognition helices for insertion into the major grooves of target DNA, supporting its role in regulating anti-CRISPRs. Furthermore, database comparisons identified uncharacterized Aca2 structural homologs in pathogenic bacteria, suggesting that Aca2 represents the first characterized member of a more widespread family of transcriptional regulators.
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Affiliation(s)
- Ben Usher
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Izaak N Beck
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Robert D Fagerlund
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Bio-Protection Research Centre, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Tim R Blower
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK.
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