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Saunier M, Fortier LC, Soutourina O. RNA-based regulation in bacteria-phage interactions. Anaerobe 2024; 87:102851. [PMID: 38583547 DOI: 10.1016/j.anaerobe.2024.102851] [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: 12/31/2023] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Interactions of bacteria with their viruses named bacteriophages or phages shape the bacterial genome evolution and contribute to the diversity of phages. RNAs have emerged as key components of several anti-phage defense systems in bacteria including CRISPR-Cas, toxin-antitoxin and abortive infection. Frequent association with mobile genetic elements and interplay between different anti-phage defense systems are largely discussed. Newly discovered defense systems such as retrons and CBASS include RNA components. RNAs also perform their well-recognized regulatory roles in crossroad of phage-bacteria regulatory networks. Both regulatory and defensive function can be sometimes attributed to the same RNA molecules including CRISPR RNAs. This review presents the recent advances on the role of RNAs in the bacteria-phage interactions with a particular focus on clostridial species including an important human pathogen, Clostridioides difficile.
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Affiliation(s)
- Marion Saunier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Institut Universitaire de France (IUF), Paris, France.
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2
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Zheng L, Shen J, Chen R, Hu Y, Zhao W, Leung ELH, Dai L. Genome engineering of the human gut microbiome. J Genet Genomics 2024; 51:479-491. [PMID: 38218395 DOI: 10.1016/j.jgg.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/15/2024]
Abstract
The human gut microbiome, a complex ecosystem, significantly influences host health, impacting crucial aspects such as metabolism and immunity. To enhance our comprehension and control of the molecular mechanisms orchestrating the intricate interplay between gut commensal bacteria and human health, the exploration of genome engineering for gut microbes is a promising frontier. Nevertheless, the complexities and diversities inherent in the gut microbiome pose substantial challenges to the development of effective genome engineering tools for human gut microbes. In this comprehensive review, we provide an overview of the current progress and challenges in genome engineering of human gut commensal bacteria, whether executed in vitro or in situ. A specific focus is directed towards the advancements and prospects in cargo DNA delivery and high-throughput techniques. Additionally, we elucidate the immense potential of genome engineering methods to enhance our understanding of the human gut microbiome and engineer the microorganisms to enhance human health.
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Affiliation(s)
- Linggang Zheng
- Dr Neher's Biophysics Laboratory for Innovative Drug Discovery/State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macau 999078, China; CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Juntao Shen
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Ruiyue Chen
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yucan Hu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Zhao
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Elaine Lai-Han Leung
- Cancer Center, Faculty of Health Science, University of Macau, Macau 999078, China; MOE Frontiers Science Center for Precision Oncology, University of Macau, Macau 999078, China.
| | - Lei Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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3
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Brehm JN, Sorg JA. Theophylline-based control of repA on a Clostridioides difficile plasmid for use in allelic exchange. Anaerobe 2024; 88:102858. [PMID: 38692475 DOI: 10.1016/j.anaerobe.2024.102858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
Historically, mutagenesis in the non-model enteropathogenic bacterium Clostridioides difficile has been challenging. Developing a versatile and reliable method of generating targeted mutations in C. difficile is important to further our understanding of its pathogenesis. Some of the most common targeted mutagenesis systems rely on allelic exchange mediated by either uracil auxotrophy combined with a toxic uracil precursor, a toxin/anti-toxin system, group II introns, or CRISPR/Cas mutagenesis. However, each of these methods suffers from its own issues. Here, we develop and test an allelic exchange strategy which better facilitates screening for integration and selecting for excision than previous systems. This is achieved by controlling plasmid replication with a theophylline-dependent riboswitch cloned upstream of repA, the gene whose product controls plasmid replication. This allows efficient mutant generation, can be performed in a wild-type strain of C. difficile, does not have the off-target effects inherent to group II introns, and alleviates the problem of testing multiple gRNA targets in CRISPR mutagenesis.
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Affiliation(s)
- Joshua N Brehm
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA.
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4
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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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5
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Xu Z, Chen S, Wu W, Wen Y, Cao H. Type I CRISPR-Cas-mediated microbial gene editing and regulation. AIMS Microbiol 2023; 9:780-800. [PMID: 38173969 PMCID: PMC10758571 DOI: 10.3934/microbiol.2023040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/03/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
There are six major types of CRISPR-Cas systems that provide adaptive immunity in bacteria and archaea against invasive genetic elements. The discovery of CRISPR-Cas systems has revolutionized the field of genetics in many organisms. In the past few years, exploitations of the most abundant class 1 type I CRISPR-Cas systems have revealed their great potential and distinct advantages to achieve gene editing and regulation in diverse microorganisms in spite of their complicated structures. The widespread and diversified type I CRISPR-Cas systems are becoming increasingly attractive for the development of new biotechnological tools, especially in genetically recalcitrant microbial strains. In this review article, we comprehensively summarize recent advancements in microbial gene editing and regulation by utilizing type I CRISPR-Cas systems. Importantly, to expand the microbial host range of type I CRISPR-Cas-based applications, these structurally complicated systems have been improved as transferable gene-editing tools with efficient delivery methods for stable expression of CRISPR-Cas elements, as well as convenient gene-regulation tools with the prevention of DNA cleavage by obviating deletion or mutation of the Cas3 nuclease. We envision that type I CRISPR-Cas systems will largely expand the biotechnological toolbox for microbes with medical, environmental and industrial importance.
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Affiliation(s)
- Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Shuzhen Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Weiyan Wu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Yongqi Wen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China
| | - Huiluo Cao
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
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6
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Godana EA, Yang Q, Zhang X, Zhao L, Wang K, Dhanasekaran S, Mehari TG, Zhang H. Biotechnological and Biocontrol Approaches for Mitigating Postharvest Diseases Caused by Fungal Pathogens and Their Mycotoxins in Fruits: A Review. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:17584-17596. [PMID: 37938803 DOI: 10.1021/acs.jafc.3c06448] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Postharvest diseases caused by fungal pathogens are significant contributors to the postharvest losses of fruits. Moreover, some fungal pathogens produce mycotoxins, which further compromise the safety and quality of fruits. In this review, the potential of biotechnological and biocontrol approaches for mitigating postharvest diseases and mycotoxins in fruits is explored. The review begins by discussing the impact of postharvest diseases on fruit quality and postharvest losses. Next, it provides an overview of major postharvest diseases caused by fungal pathogens. Subsequently, it delves into the role of biotechnological approaches in controlling these diseases. The review also explored the application of biocontrol agents, such as antagonistic yeasts, bacteria, and fungi, which can suppress pathogen growth. Furthermore, future trends and challenges in these two approaches are discussed in detail. Overall, this review can provide insights into promising biotechnological and biocontrol strategies for managing postharvest diseases and mycotoxins in fruits.
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Affiliation(s)
- Esa Abiso Godana
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Qiya Yang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Xiaoyun Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Lina Zhao
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Kaili Wang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | - Solairaj Dhanasekaran
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
| | | | - Hongyin Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
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7
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Garvey M. Foodborne Clostridioides Species: Pathogenicity, Virulence and Biocontrol Options. Microorganisms 2023; 11:2483. [PMID: 37894141 PMCID: PMC10609181 DOI: 10.3390/microorganisms11102483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/22/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Clostridioides species possess many virulence factors and alarming levels of muti-drug resistance which make them a significant risk to public health safety and a causative agent of livestock disease. Clostridioides result in serious systemic and gastrointestinal diseases such as myonecrosis, colitis, food poisoning and gastroenteritis. As foodborne pathogens, Clostridioides species are associated with significant incidences of morbidity and mortality where the application of broad-spectrum antibiotics predisposes patients to virulent Clostridioides colonisation. As part of the One Health approach, there is an urgent need to eliminate the use of antibiotics in food production to safeguard animals, humans and the environment. Alternative options are warranted to control foodborne pathogens at all stages of food production. Antimicrobial peptides and bacteriophages have demonstrated efficacy against Clostridioides species and may offer antimicrobial biocontrol options. The bacteriocin nisin, for example, has been implemented as a biopreservative for the control of Listeria, Staphylococcus and Clostridia species in food. Bacteriophage preparations have also gained recognition for the antibacterial action against highly virulent bacterial species including foodborne pathogens. Studies are warranted to mitigate the formulation and administration limitations associated with the application of such antimicrobials as biocontrol strategies. This review outlines foodborne Clostridioides species, their virulence factors, and potential biocontrol options for application in food production.
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Affiliation(s)
- Mary Garvey
- Department of Life Science, Atlantic Technological University, Ash Lane, F91 YW50 Sligo, Ireland;
- Centre for Precision Engineering, Materials and Manufacturing Research (PEM), Atlantic Technological University, F91 YW50 Sligo, Ireland
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8
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Dong Q, Lin H, Allen MM, Garneau JR, Sia JK, Smith RC, Haro F, McMillen T, Pope RL, Metcalfe C, Burgo V, Woodson C, Dylla N, Kohout C, Sundararajan A, Snitkin ES, Young VB, Fortier LC, Kamboj M, Pamer EG. Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile. Cell Rep 2023; 42:112861. [PMID: 37523264 PMCID: PMC10627504 DOI: 10.1016/j.celrep.2023.112861] [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: 01/23/2023] [Revised: 05/01/2023] [Accepted: 07/07/2023] [Indexed: 08/02/2023] Open
Abstract
Clostridioides difficile produces toxins that damage the colonic epithelium, causing colitis. Variation in disease severity is poorly understood and has been attributed to host factors and virulence differences between C. difficile strains. We test 23 epidemic ST1 C. difficile clinical isolates for their virulence in mice. All isolates encode a complete Tcd pathogenicity locus and achieve similar colonization densities. However, disease severity varies from lethal to avirulent infections. Genomic analysis of avirulent isolates reveals a 69-bp deletion in the cdtR gene, which encodes a response regulator for binary toxin expression. Deleting the 69-bp sequence in virulent R20291 strain renders it avirulent in mice with reduced toxin gene transcription. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile isolates without reducing colonization and persistence. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.
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Affiliation(s)
- Qiwen Dong
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA.
| | - Huaiying Lin
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Marie-Maude Allen
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Julian R Garneau
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Jonathan K Sia
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rita C Smith
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Fidel Haro
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Tracy McMillen
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rosemary L Pope
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
| | - Carolyn Metcalfe
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Victoria Burgo
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Che Woodson
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Nicholas Dylla
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Claire Kohout
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | | | - Evan S Snitkin
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent B Young
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Mini Kamboj
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Eric G Pamer
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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9
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Shangguan Q, White MF. Repurposing the atypical type I-G CRISPR system for bacterial genome engineering. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001373. [PMID: 37526970 PMCID: PMC10482374 DOI: 10.1099/mic.0.001373] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/18/2023] [Indexed: 08/02/2023]
Abstract
The CRISPR-Cas system functions as a prokaryotic immune system and is highly diverse, with six major types and numerous sub-types. The most abundant are type I CRISPR systems, which utilize a multi-subunit effector, Cascade, and a CRISPR RNA (crRNA) to detect invading DNA species. Detection leads to DNA loading of the Cas3 helicase-nuclease, leading to long-range deletions in the targeted DNA, thus providing immunity against mobile genetic elements (MGE). Here, we focus on the type I-G system, a streamlined, 4-subunit complex with an atypical Cas3 enzyme. We demonstrate that Cas3 helicase activity is not essential for immunity against MGE in vivo and explore applications of the Thioalkalivibrio sulfidiphilus Cascade effector for genome engineering in Escherichia coli. Long-range, bidirectional deletions were observed when the lacZ gene was targeted. Deactivation of the Cas3 helicase activity dramatically altered the types of deletions observed, with small deletions flanked by direct repeats that are suggestive of microhomology mediated end joining. When donor DNA templates were present, both the wild-type and helicase-deficient systems promoted homology-directed repair (HDR), with the latter system providing improvements in editing efficiency, suggesting that a single nick in the target site may promote HDR in E. coli using the type I-G system. These findings open the way for further application of the type I-G CRISPR systems in genome engineering.
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Affiliation(s)
- Qilin Shangguan
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, UK
| | - Malcolm F. White
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, UK
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10
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Poulalier-Delavelle M, Baker JP, Millard J, Winzer K, Minton NP. Endogenous CRISPR/Cas systems for genome engineering in the acetogens Acetobacterium woodii and Clostridium autoethanogenum. Front Bioeng Biotechnol 2023; 11:1213236. [PMID: 37425362 PMCID: PMC10328091 DOI: 10.3389/fbioe.2023.1213236] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Acetogenic bacteria can play a major role in achieving Net Zero through their ability to convert CO2 into industrially relevant chemicals and fuels. Full exploitation of this potential will be reliant on effective metabolic engineering tools, such as those based on the Streptococcus pyogenes CRISPR/Cas9 system. However, attempts to introduce cas9-containing vectors into Acetobacterium woodii were unsuccessful, most likely as a consequence of Cas9 nuclease toxicity and the presence of a recognition site for an endogenous A. woodii restriction-modification (R-M) system in the cas9 gene. As an alternative, this study aims to facilitate the exploitation of CRISPR/Cas endogenous systems as genome engineering tools. Accordingly, a Python script was developed to automate the prediction of protospacer adjacent motif (PAM) sequences and used to identify PAM candidates of the A. woodii Type I-B CRISPR/Cas system. The identified PAMs and the native leader sequence were characterized in vivo by interference assay and RT-qPCR, respectively. Expression of synthetic CRISPR arrays, consisting of the native leader sequence, direct repeats, and adequate spacer, along with an editing template for homologous recombination, successfully led to the creation of 300 bp and 354 bp in-frame deletions of pyrE and pheA, respectively. To further validate the method, a 3.2 kb deletion of hsdR1 was also generated, as well as the knock-in of the fluorescence-activating and absorption-shifting tag (FAST) reporter gene at the pheA locus. Homology arm length, cell density, and the amount of DNA used for transformation were found to significantly impact editing efficiencies. The devised workflow was subsequently applied to the Type I-B CRISPR/Cas system of Clostridium autoethanogenum, enabling the generation of a 561 bp in-frame deletion of pyrE with 100% editing efficiency. This is the first report of genome engineering of both A. woodii and C. autoethanogenum using their endogenous CRISPR/Cas systems.
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Affiliation(s)
| | | | | | | | - Nigel P. Minton
- *Correspondence: Margaux Poulalier-Delavelle, ; Nigel P. Minton,
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11
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Fuchs M, Lamm-Schmidt V, Lenče T, Sulzer J, Bublitz A, Wackenreuter J, Gerovac M, Strowig T, Faber F. A network of small RNAs regulates sporulation initiation in Clostridioides difficile. EMBO J 2023:e112858. [PMID: 37140366 DOI: 10.15252/embj.2022112858] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 05/05/2023] Open
Abstract
The obligate anaerobic, enteric pathogen Clostridioides difficile persists in the intestinal tract by forming antibiotic-resistant endospores that contribute to relapsing and recurrent infections. Despite the importance of sporulation for C. difficile pathogenesis, environmental cues and molecular mechanisms that regulate sporulation initiation remain ill-defined. Here, by using RIL-seq to globally capture the Hfq-dependent RNA-RNA interactome, we discovered a network of small RNAs that bind to mRNAs encoding sporulation-related genes. We show that two of these small RNAs, SpoX and SpoY, regulate translation of the master regulator of sporulation, Spo0A, in an opposing manner, which ultimately leads to altered sporulation rates. Infection of antibiotic-treated mice with SpoX and SpoY deletion mutants revealed a global effect on gut colonization and intestinal sporulation. Our work uncovers an elaborate RNA-RNA interactome controlling the physiology and virulence of C. difficile and identifies a complex post-transcriptional layer in the regulation of spore formation in this important human pathogen.
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Affiliation(s)
- Manuela Fuchs
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Vanessa Lamm-Schmidt
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Tina Lenče
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Johannes Sulzer
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Arne Bublitz
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Janet Wackenreuter
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
| | - Milan Gerovac
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
| | - Till Strowig
- Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
- German Center for Infection Research (DZIF), Hannover-Braunschweig, Germany
| | - Franziska Faber
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), Julius-Maximilians-University of Würzburg (JMU), Würzburg, Germany
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12
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Rashid SJ, Nale JY, Millard AD, Clokie MRJ. Novel ribotype/sequence type associations and diverse CRISPR-Cas systems in environmental Clostridioides difficile strains from northern Iraq. FEMS Microbiol Lett 2023; 370:fnad091. [PMID: 37723612 PMCID: PMC10806358 DOI: 10.1093/femsle/fnad091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 07/27/2023] [Accepted: 09/15/2023] [Indexed: 09/20/2023] Open
Abstract
The environment is a natural reservoir of Clostridioides difficile, and here, we aimed to isolate the pathogen from seven locations in northern Iraq. Four of the sites yielded thirty-one isolates (ten from soils, twenty-one from sediments), which together represent ribotypes (RTs) 001 (five), 010 (five), 011 (two), 035 (two), 091 (eight), and 604 (nine). Twenty-five of the isolates (∼81%) are non-toxigenic, while six (∼19%) encode the toxin A and B genes. The genomes of eleven selected isolates represent six sequence types (STs): ST-3 (two), ST-15 (one), ST-107 (five), ST-137 (one), ST-177 (one), and ST-181 (one). Five novel RT/ST associations: RT011/ST-137, RT035/ST-107, RT091/ST-107, RT604/ST-177, and RT604/ST-181 were identified, and the first three are linked to RTs previously uncharacterized by multilocus sequence typing (MLST). Nine of the genomes belong to Clade 1, and two are closely related to the cryptic C-I clade. Diverse multiple prophages and CRISPR-Cas systems (class 1 subtype I-B1 and class 2 type V CRISPR-Cas systems) with spacers identical to other C. difficile phages and plasmids were detected in the genomes. Our data show the broader diversity that exists within environmental C. difficile strains from a much less studied location and their potential role in the evolution and emergence of new strains.
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Affiliation(s)
- Srwa J Rashid
- Medical Laboratory Technology Department, Koya Technical Institute, Erbil Polytechnic University, Erbil, Kurdistan, Iraq
| | - Janet Y Nale
- Centre for Epidemiology and Planetary Health, Scotland’s Rural College, Inverness IV2 5NA, UK
| | - Andrew D Millard
- Department of Genetics and Genome Biology, College of Life Sciences, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Martha R J Clokie
- Department of Genetics and Genome Biology, College of Life Sciences, University of Leicester, University Road, Leicester LE1 7RH, UK
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13
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Make It Less difficile: Understanding Genetic Evolution and Global Spread of Clostridioides difficile. Genes (Basel) 2022; 13:genes13122200. [PMID: 36553467 PMCID: PMC9778335 DOI: 10.3390/genes13122200] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Clostridioides difficile is an obligate anaerobic pathogen among the most common causes of healthcare-associated infections. It poses a global threat due to the clinical outcomes of infection and resistance to antibiotics recommended by international guidelines for its eradication. In particular, C. difficile infection can lead to fulminant colitis associated with shock, hypotension, megacolon, and, in severe cases, death. It is therefore of the utmost urgency to fully characterize this pathogen and better understand its spread, in order to reduce infection rates and improve therapy success. This review aims to provide a state-of-the-art overview of the genetic variation of C. difficile, with particular regard to pathogenic genes and the correlation with clinical issues of its infection. We also summarize the current typing techniques and, based on them, the global distribution of the most common ribotypes. Finally, we discuss genomic surveillance actions and new genetic engineering strategies as future perspectives to make it less difficile.
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14
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LeBlanc N, Charles TC. Bacterial genome reductions: Tools, applications, and challenges. Front Genome Ed 2022; 4:957289. [PMID: 36120530 PMCID: PMC9473318 DOI: 10.3389/fgeed.2022.957289] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/29/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial cells are widely used to produce value-added products due to their versatility, ease of manipulation, and the abundance of genome engineering tools. However, the efficiency of producing these desired biomolecules is often hindered by the cells’ own metabolism, genetic instability, and the toxicity of the product. To overcome these challenges, genome reductions have been performed, making strains with the potential of serving as chassis for downstream applications. Here we review the current technologies that enable the design and construction of such reduced-genome bacteria as well as the challenges that limit their assembly and applicability. While genomic reductions have shown improvement of many cellular characteristics, a major challenge still exists in constructing these cells efficiently and rapidly. Computational tools have been created in attempts at minimizing the time needed to design these organisms, but gaps still exist in modelling these reductions in silico. Genomic reductions are a promising avenue for improving the production of value-added products, constructing chassis cells, and for uncovering cellular function but are currently limited by their time-consuming construction methods. With improvements to and the creation of novel genome editing tools and in silico models, these approaches could be combined to expedite this process and create more streamlined and efficient cell factories.
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Affiliation(s)
- Nicole LeBlanc
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
- *Correspondence: Nicole LeBlanc,
| | - Trevor C. Charles
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
- Metagenom Bio Life Science Inc., Waterloo, ON, Canada
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15
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Exploiting the Type I-B CRISPR Genome Editing System in Thermoanaerobacterium aotearoense SCUT27 and Engineering the Strain for Enhanced Ethanol Production. Appl Environ Microbiol 2022; 88:e0075122. [PMID: 35862665 PMCID: PMC9361813 DOI: 10.1128/aem.00751-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Thermoanaerobacterium aotearoense strain SCUT27 is a potential industrial biofuel-producing strain because of its broad substrate spectrum, especially the ability to co-use glucose and xylose. The bottleneck hindering the development of strain SCUT27 is the lack of selective markers for polygene manipulation in this thermophilic bacterium. In this study, the endogenous type I-B clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system was developed for multiplex genome editing of strain SCUT27. The protospacer-adjacent motif was identified by in silico analysis and verified with orotidine-5'-phosphate decarboxylase (pyrF) or lactate dehydrogenase (ldh) as the editing target. The type I-B CRISPR/Cas system was functional in strain SCUT27 with 58.3% to 100% editing efficiency. A multiplex genome editing method based on thymidine kinase (tdk) as a negative selection marker was developed, and strain SCUT27/Δtdk/Δldh/ΔargR, in which ldh and the arginine repressor (argR) were knocked out successively, was successfully obtained. Strain SCUT27/Δtdk/Δldh/ΔargR exhibited prominent advantages over wild-type SCUT27 in ethanol production, with significantly improved ability to metabolize xylose. IMPORTANCE Thermophilic microbes have attracted great attention as potential candidates for production of biofuels and chemicals from lignocellulose because of their thermal tolerance and wide substrate spectra. The ability to edit multiple genes using the native type I-B CRISPR/Cas system would speed up engineering of Thermoanaerobacterium aotearoense strain SCUT27 for higher ethanol production from lignocellulosic hydrolysates. Here, we produced a mutant strain, T. aotearoense SCUT27/Δtdk/Δldh/ΔargR, using the native CRISPR/Cas system. The engineered strain showed satisfactory performance with improved ethanol productivity from various lignocellulosic hydrolysates. Our data lay the foundations for development of this thermophilic microbe into an excellent ethanol producer using lignocellulosic hydrolysates. The methods described here may also provide a reference to develop multigene editing methods for other microorganisms.
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16
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Prakash A, Kumar M. Transcriptional analysis of CRISPR I-B arrays of Leptospira interrogans serovar Lai and its processing by Cas6. Front Microbiol 2022; 13:960559. [PMID: 35966677 PMCID: PMC9372919 DOI: 10.3389/fmicb.2022.960559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022] Open
Abstract
In the genome of various Leptospira interrogans serovars, the subtype I-B locus of CRISPR-Cas possesses either one or multiple CRISPR arrays. In silico database (CRISPRCasdb) for predicting CRISPR-Cas reveals seven CRISPR arrays in L. interrogans serovar Lai positioned between the two independent cas-operons. Here, we present the redefined repeat-spacer boundaries of the CRISPR subtype I-B locus of serovar Lai. Such refinement of boundaries of arrays in serovar Lai was done after comparison with the characterized array of another serovar Copenhageni and the manual analysis of CRISPR flanking sequences. Using the reverse transcription-PCR (RT-PCR), we account that the seven CRISPR are transcriptionally active in serovar Lai. Our RT-PCR and quantitative real-time PCR analysis of transcripts in serovar Lai indicated that seven CRISPR of subtype I-B transcribe together as a single precursor unit. Moreover, the cleavage of the two miniature pre-crRNA of the subtype I-B by Cas6 demonstrates the biogenesis of the expected size of mature crRNA essential for the guided interference of foreign DNA. This study features insight into transcription direction and the crRNA biogenesis in serovar Lai essential for RNA-mediated interference of invading nucleic acids.
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17
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Genomic and epigenetic landscapes drive CRISPR-based genome editing in Bifidobacterium. Proc Natl Acad Sci U S A 2022; 119:e2205068119. [PMID: 35857876 PMCID: PMC9335239 DOI: 10.1073/pnas.2205068119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Bifidobacterium is a commensal bacterial genus ubiquitous in the human gastrointestinal tract, which is associated with a range of health benefits. The advent of CRISPR-based genome editing technologies provides opportunities to investigate the genetics of important bacteria and transcend the lack of genetic tools in bifidobacteria to study the basis for their health-promoting attributes. Here, we repurpose the endogenous type I-G CRISPR-Cas system and adopt an exogenous CRISPR base editor for genome engineering in B. animalis subsp. lactis, demonstrating that both genomic and epigenetic contexts drive editing outcomes across strains. We reprogrammed the endogenous type I-G system to screen for naturally occurring large deletions up to 27 kb and to generate a 500-bp deletion in tetW to abolish tetracycline resistance. A CRISPR-cytosine base editor was optimized to install C•G-to-T•A amber mutations to resensitize multiple B. lactis strains to tetracycline. Remarkably, we uncovered epigenetic patterns that are distributed unevenly among B. lactis strains, despite their genomic homogeneity, that may contribute to editing efficiency variability. Insights were also expanded to Bifidobacterium longum subsp. infantis to emphasize the broad relevance of these findings. This study highlights the need to develop individualized CRISPR-based genome engineering approaches for distinct bacterial strains and opens avenues for engineering of next generation probiotics.
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18
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Jiang D, Zhang D, Li S, Liang Y, Zhang Q, Qin X, Gao J, Qiu J. Highly efficient genome editing in Xanthomonas oryzae pv. oryzae through repurposing the endogenous type I-C CRISPR-Cas system. MOLECULAR PLANT PATHOLOGY 2022; 23:583-594. [PMID: 34954876 PMCID: PMC8916207 DOI: 10.1111/mpp.13178] [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] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/25/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Efficient and modular genome editing technologies that manipulate the genome of bacterial pathogens will facilitate the study of pathogenesis mechanisms. However, such methods are yet to be established for Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight. We identified a single type I-C CRISPR-Cas system in the Xoo genome and leveraged this endogenous defence system for high-efficiency genome editing in Xoo. Specifically, we developed plasmid components carrying a mini-CRISPR array, donor DNA, and a phage-derived recombination system to enable the efficient and programmable genome editing of precise deletions, insertions, base substitutions, and gene replacements. Furthermore, the type I-C CRISPR-Cas system of Xoo cleaves target DNA unidirectionally, and this can be harnessed to generate large genomic deletions up to 212 kb efficiently. Therefore, the genome-editing strategy we have developed can serve as an excellent tool for functional genomics of Xoo, and should also be applicable to other CRISPR-harbouring bacterial plant pathogens.
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Affiliation(s)
- Dandan Jiang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic InteractionsUniversity of Chinese Academy of SciencesBeijingChina
| | - Dandan Zhang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Shengnan Li
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Yueting Liang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic InteractionsUniversity of Chinese Academy of SciencesBeijingChina
| | - Qianwei Zhang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic InteractionsUniversity of Chinese Academy of SciencesBeijingChina
| | - Xu Qin
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic InteractionsUniversity of Chinese Academy of SciencesBeijingChina
| | - Jinlan Gao
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Jin‐Long Qiu
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Biotic InteractionsUniversity of Chinese Academy of SciencesBeijingChina
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19
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Clostridioides difficile - phage relationship the RNA way. Curr Opin Microbiol 2021; 66:1-10. [PMID: 34922145 DOI: 10.1016/j.mib.2021.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/06/2021] [Accepted: 11/28/2021] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile (formerly Clostridium difficile)-associated diarrhea is currently the most frequently occurring nosocomial diarrhea worldwide. During its infection cycle this pathogen needs to survive in phage-rich gut communities. Recent data strongly suggest that regulatory RNAs control gene expression in C. difficile and many of these RNAs appear to modulate C. difficile-phage interactions. Of the 200 regulatory RNAs identified by deep sequencing and targeted approaches, many function as antitoxins within type I toxin-antitoxin modules and CRISPR RNAs for anti-phage defenses. In this review, we discuss recent insights into the role of RNAs in modulating interactions between C. difficile and phages in light of intriguing data in other prokaryotes.
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20
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Maikova A, Boudry P, Shiriaeva A, Vasileva A, Boutserin A, Medvedeva S, Semenova E, Severinov K, Soutourina O. Protospacer-Adjacent Motif Specificity during Clostridioides difficile Type I-B CRISPR-Cas Interference and Adaptation. mBio 2021; 12:e0213621. [PMID: 34425703 PMCID: PMC8406132 DOI: 10.1128/mbio.02136-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems provide prokaryotes with efficient protection against foreign nucleic acid invaders. We have recently demonstrated the defensive interference function of a CRISPR-Cas system from Clostridioides (Clostridium) difficile, a major human enteropathogen, and showed that it could be harnessed for efficient genome editing in this bacterium. However, molecular details are still missing on CRISPR-Cas function for adaptation and sequence requirements for both interference and new spacer acquisition in this pathogen. Despite accumulating knowledge on the individual CRISPR-Cas systems in various prokaryotes, no data are available on the adaptation process in bacterial type I-B CRISPR-Cas systems. Here, we report the first experimental evidence that the C. difficile type I-B CRISPR-Cas system acquires new spacers upon overexpression of its adaptation module. The majority of new spacers are derived from a plasmid expressing Cas proteins required for adaptation or from regions of the C. difficile genome where generation of free DNA termini is expected. Results from protospacer-adjacent motif (PAM) library experiments and plasmid conjugation efficiency assays indicate that C. difficile CRISPR-Cas requires the YCN consensus PAM for efficient interference. We revealed a functional link between the adaptation and interference machineries, since newly adapted spacers are derived from sequences associated with a CCN PAM, which fits the interference consensus. The definition of functional PAMs and establishment of relative activity levels of each of the multiple C. difficile CRISPR arrays in present study are necessary for further CRISPR-based biotechnological and medical applications involving this organism. IMPORTANCE CRISPR-Cas systems provide prokaryotes with adaptive immunity for defense against foreign nucleic acid invaders, such as viruses or phages and plasmids. The CRISPR-Cas systems are highly diverse, and detailed studies of individual CRISPR-Cas subtypes are important for our understanding of various aspects of microbial adaptation strategies and for the potential applications. The significance of our work is in providing the first experimental evidence for type I-B CRISPR-Cas system adaptation in the emerging human enteropathogen Clostridioides difficile. This bacterium needs to survive in phage-rich gut communities, and its active CRISPR-Cas system might provide efficient antiphage defense by acquiring new spacers that constitute memory for further invader elimination. Our study also reveals a functional link between the adaptation and interference CRISPR machineries. The definition of all possible functional trinucleotide motifs upstream protospacers within foreign nucleic acid sequences is important for CRISPR-based genome editing in this pathogen and for developing new drugs against C. difficile infections.
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Affiliation(s)
- Anna Maikova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Pierre Boudry
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anna Shiriaeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Aleksandra Vasileva
- Institute of Gene Biology, Centre for Precision Genome Editing and Genetic Technologies for Biomedicine, Russian Academy of Sciences, Moscow, Russia
| | - Anaïs Boutserin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Sofia Medvedeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ekaterina Semenova
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin Severinov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Molecular Genetics, Russian Academy of Sciences, 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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21
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Monteford J, Bilverstone TW, Ingle P, Philip S, Kuehne SA, Minton NP. What's a SNP between friends: The lineage of Clostridioides difficile R20291 can effect research outcomes. Anaerobe 2021; 71:102422. [PMID: 34343672 PMCID: PMC8556159 DOI: 10.1016/j.anaerobe.2021.102422] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022]
Abstract
Clostridioides difficile R20291 is the most studied PCR-Ribotype 027 isolate. The two predominant lineages of this hypervirulent strain, however, exhibit substantive phenotypic differences and possess genomes that differ by a small number of nucleotide changes. It is important that the source of R20291 is taken into account in research outcomes. Two phenotypically distinct lineages of C. difficile R20291 are in circulation. Affected are gene transfer, motility, sporulation, biofilm and toxin production. The differences are due to a small number of single nucleotide genomic changes. These findings underline the importance of appropriately maintaining stock cultures. The source of R20291 should be stated in any investigation.
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Affiliation(s)
- Jorge Monteford
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Terry W Bilverstone
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK; NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, NG7 2RD, UK
| | - Patrick Ingle
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK; NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sheryl Philip
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK; Biocatalysts Limited, Unit 1, Cefn Coed, Parc Nantgarw, Cardiff, CF15 7QQ, UK
| | - Sarah A Kuehne
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK; Oral Microbiology Group, School of Dentistry and Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, B5 7EG, UK
| | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Biodiscovery Institute, The University of Nottingham, Nottingham, NG7 2RD, UK; NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, NG7 2RD, UK.
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22
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Joseph RC, Kelley SQ, Kim NM, Sandoval NR. Metabolic Engineering and the Synthetic Biology Toolbox for
Clostridium. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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An RNA-centric global view of Clostridioides difficile reveals broad activity of Hfq in a clinically important gram-positive bacterium. Proc Natl Acad Sci U S A 2021; 118:2103579118. [PMID: 34131082 PMCID: PMC8237595 DOI: 10.1073/pnas.2103579118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The gram-positive human pathogen Clostridioides difficile has emerged as the leading cause of antibiotic-associated diarrhea. However, little is known about the bacterium's transcriptome architecture and mechanisms of posttranscriptional control. Here, we have applied transcription start site and termination mapping to generate a single-nucleotide-resolution RNA map of C. difficile 5' and 3' untranslated regions, operon structures, and noncoding regulators, including 42 sRNAs. Our results indicate functionality of many conserved riboswitches and predict cis-regulatory RNA elements upstream of multidrug resistance (MDR)-type ATP-binding cassette (ABC) transporters and transcriptional regulators. Despite growing evidence for a role of Hfq in RNA-based gene regulation in C. difficile, the functions of Hfq-based posttranscriptional regulatory networks in gram-positive pathogens remain controversial. Using Hfq immunoprecipitation followed by sequencing of bound RNA species (RIP-seq), we identify a large cohort of transcripts bound by Hfq and show that absence of Hfq affects transcript stabilities and steady-state levels. We demonstrate sRNA expression during intestinal colonization by C. difficile and identify infection-related signals impacting its expression. As a proof of concept, we show that the utilization of the abundant intestinal metabolite ethanolamine is regulated by the Hfq-dependent sRNA CDIF630nc_085. Overall, our study lays the foundation for understanding clostridial riboregulation with implications for the infection process and provides evidence for a global role of Hfq in posttranscriptional regulation in a gram-positive bacterium.
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24
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Fackler N, Heijstra BD, Rasor BJ, Brown H, Martin J, Ni Z, Shebek KM, Rosin RR, Simpson SD, Tyo KE, Giannone RJ, Hettich RL, Tschaplinski TJ, Leang C, Brown SD, Jewett MC, Köpke M. Stepping on the Gas to a Circular Economy: Accelerating Development of Carbon-Negative Chemical Production from Gas Fermentation. Annu Rev Chem Biomol Eng 2021; 12:439-470. [PMID: 33872517 DOI: 10.1146/annurev-chembioeng-120120-021122] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Owing to rising levels of greenhouse gases in our atmosphere and oceans, climate change poses significant environmental, economic, and social challenges globally. Technologies that enable carbon capture and conversion of greenhouse gases into useful products will help mitigate climate change by enabling a new circular carbon economy. Gas fermentation usingcarbon-fixing microorganisms offers an economically viable and scalable solution with unique feedstock and product flexibility that has been commercialized recently. We review the state of the art of gas fermentation and discuss opportunities to accelerate future development and rollout. We discuss the current commercial process for conversion of waste gases to ethanol, including the underlying biology, challenges in process scale-up, and progress on genetic tool development and metabolic engineering to expand the product spectrum. We emphasize key enabling technologies to accelerate strain development for acetogens and other nonmodel organisms.
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Affiliation(s)
- Nick Fackler
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
| | | | - Blake J Rasor
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Hunter Brown
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Jacob Martin
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Zhuofu Ni
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Kevin M Shebek
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Rick R Rosin
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
| | - Séan D Simpson
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
| | - Keith E Tyo
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , ,
| | - Richard J Giannone
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA; ,
| | - Robert L Hettich
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA; ,
| | | | - Ching Leang
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
| | - Steven D Brown
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA; , , , , , , .,Robert H. Lurie Comprehensive Cancer Center and Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, USA
| | - Michael Köpke
- LanzaTech Inc., Skokie, Illinois 60077, USA; , , , , , ,
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25
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Genome Editing in Bacteria: CRISPR-Cas and Beyond. Microorganisms 2021; 9:microorganisms9040844. [PMID: 33920749 PMCID: PMC8071187 DOI: 10.3390/microorganisms9040844] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/11/2022] Open
Abstract
Genome editing in bacteria encompasses a wide array of laborious and multi-step methods such as suicide plasmids. The discovery and applications of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas based technologies have revolutionized genome editing in eukaryotic organisms due to its simplicity and programmability. Nevertheless, this system has not been as widely favored for bacterial genome editing. In this review, we summarize the main approaches and difficulties associated with CRISPR-Cas-mediated genome editing in bacteria and present some alternatives to circumvent these issues, including CRISPR nickases, Cas12a, base editors, CRISPR-associated transposases, prime-editing, endogenous CRISPR systems, and the use of pre-made ribonucleoprotein complexes of Cas proteins and guide RNAs. Finally, we also address fluorescent-protein-based methods to evaluate the efficacy of CRISPR-based systems for genome editing in bacteria. CRISPR-Cas still holds promise as a generalized genome-editing tool in bacteria and is developing further optimization for an expanded application in these organisms. This review provides a rarely offered comprehensive view of genome editing. It also aims to familiarize the microbiology community with an ever-growing genome-editing toolbox for bacteria.
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Wilding-Steele T, Ramette Q, Jacottin P, Soucaille P. Improved CRISPR/Cas9 Tools for the Rapid Metabolic Engineering of Clostridium acetobutylicum. Int J Mol Sci 2021; 22:ijms22073704. [PMID: 33918190 PMCID: PMC8037352 DOI: 10.3390/ijms22073704] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/24/2021] [Accepted: 03/31/2021] [Indexed: 11/16/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas (CRISPR-associated proteins)9 tools have revolutionized biology-several highly efficient tools have been constructed that have resulted in the ability to quickly engineer model bacteria, for example, Escherichia coli. However, the use of CRISPR/Cas9 tools has lagged behind in non-model bacteria, hampering engineering efforts. Here, we developed improved CRISPR/Cas9 tools to enable efficient rapid metabolic engineering of the industrially relevant bacterium Clostridium acetobutylicum. Previous efforts to implement a CRISPR/Cas9 system in C. acetobutylicum have been hampered by the lack of tightly controlled inducible systems along with large plasmids resulting in low transformation efficiencies. We successfully integrated the cas9 gene from Streptococcuspyogenes into the genome under control of the xylose inducible system from Clostridium difficile, which we then showed resulted in a tightly controlled system. We then optimized the length of the editing cassette, resulting in a small editing plasmid, which also contained the upp gene in order to rapidly lose the plasmid using the upp/5-fluorouracil counter-selection system. We used this system to perform individual and sequential deletions of ldhA and the ptb-buk operon.
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Affiliation(s)
- Tom Wilding-Steele
- INP, TBI, INSA, UPS, Université de Toulouse, 31400 Toulouse, France; wilding-@insa-toulouse.fr (T.W.-S.); (Q.R.); (P.J.)
- Institut National de la Recherche Agronomique (INRA), UMR 792, 31077 Toulouse, France
- Centre National de la Recherche Scientifique (CNRS), UMR 5504, 31400 Toulouse, France
| | - Quentin Ramette
- INP, TBI, INSA, UPS, Université de Toulouse, 31400 Toulouse, France; wilding-@insa-toulouse.fr (T.W.-S.); (Q.R.); (P.J.)
- Institut National de la Recherche Agronomique (INRA), UMR 792, 31077 Toulouse, France
- Centre National de la Recherche Scientifique (CNRS), UMR 5504, 31400 Toulouse, France
| | - Paul Jacottin
- INP, TBI, INSA, UPS, Université de Toulouse, 31400 Toulouse, France; wilding-@insa-toulouse.fr (T.W.-S.); (Q.R.); (P.J.)
- Institut National de la Recherche Agronomique (INRA), UMR 792, 31077 Toulouse, France
- Centre National de la Recherche Scientifique (CNRS), UMR 5504, 31400 Toulouse, France
| | - Philippe Soucaille
- INP, TBI, INSA, UPS, Université de Toulouse, 31400 Toulouse, France; wilding-@insa-toulouse.fr (T.W.-S.); (Q.R.); (P.J.)
- Institut National de la Recherche Agronomique (INRA), UMR 792, 31077 Toulouse, France
- Centre National de la Recherche Scientifique (CNRS), UMR 5504, 31400 Toulouse, France
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK
- Correspondence:
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Xu Z, Li Y, Li M, Xiang H, Yan A. Harnessing the type I CRISPR-Cas systems for genome editing in prokaryotes. Environ Microbiol 2020; 23:542-558. [PMID: 32510745 DOI: 10.1111/1462-2920.15116] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 12/26/2022]
Abstract
Genetic analysis is crucial to the understanding, exploitation, and control of microorganisms. The advent of CRISPR-Cas-based genome-editing techniques, particularly those mediated by the single-effector (Cas9 and Cas12a) class 2 CRISPR-Cas systems, has revolutionized the genetics in model eukaryotic organisms. However, their applications in prokaryotes are rather limited, largely owing to the exceptional diversity of DNA homeostasis in microorganisms and severe cytotoxicity of overexpressing these nuclease proteins in certain genotypes. Remarkably, CRISPR-Cas systems belonging to different classes and types are continuously identified in prokaryotic genomes and serve as a deep reservoir for expansion of the CRISPR-based genetic toolkits. ~90% of the CRISPR-Cas systems identified so far belong to the class 1 system which hinges on multi-protein effector complexes for DNA interference. Harnessing these widespread native CRISPR-Cas systems for 'built-in' genome editing represents an emerging and powerful genetic tool in prokaryotes, especially in the genetically recalcitrant non-model species and strains. In this progress review, we introduce the general workflow of this emerging editing platform and summarize its establishment in a growing number of prokaryotes by harnessing the most widespread, diverse type I CRISPR-Cas systems present in their genomes. We also discuss the various factors affecting the success and efficiency of this editing platform and the corresponding solutions.
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Affiliation(s)
- Zeling Xu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Yanran Li
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Ming Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 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
| | - Aixin Yan
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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28
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Walker JE, Lanahan AA, Zheng T, Toruno C, Lynd LR, Cameron JC, Olson DG, Eckert CA. Development of both type I-B and type II CRISPR/Cas genome editing systems in the cellulolytic bacterium Clostridium thermocellum. Metab Eng Commun 2020; 10:e00116. [PMID: 31890588 PMCID: PMC6926293 DOI: 10.1016/j.mec.2019.e00116] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/13/2019] [Accepted: 11/25/2019] [Indexed: 12/21/2022] Open
Abstract
The robust lignocellulose-solubilizing activity of C. thermocellum makes it a top candidate for consolidated bioprocessing for biofuel production. Genetic techniques for C. thermocellum have lagged behind model organisms thus limiting attempts to improve biofuel production. To improve our ability to engineer C. thermocellum, we characterized a native Type I-B and heterologous Type II Clustered Regularly-Interspaced Short Palindromic Repeat (CRISPR)/cas (CRISPR associated) systems. We repurposed the native Type I-B system for genome editing. We tested three thermophilic Cas9 variants (Type II) and found that GeoCas9, isolated from Geobacillus stearothermophilus, is active in C. thermocellum. We employed CRISPR-mediated homology directed repair to introduce a nonsense mutation into pyrF. For both editing systems, homologous recombination between the repair template and the genome appeared to be the limiting step. To overcome this limitation, we tested three novel thermophilic recombinases and demonstrated that exo/beta homologs, isolated from Acidithiobacillus caldus, are functional in C. thermocellum. For the Type I-B system an engineered strain, termed LL1586, yielded 40% genome editing efficiency at the pyrF locus and when recombineering machinery was expressed this increased to 71%. For the Type II GeoCas9 system, 12.5% genome editing efficiency was observed and when recombineering machinery was expressed, this increased to 94%. By combining the thermophilic CRISPR system (either Type I-B or Type II) with the recombinases, we developed a new tool that allows for efficient CRISPR editing. We are now poised to enable CRISPR technologies to better engineer C. thermocellum for both increased lignocellulose degradation and biofuel production.
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Key Words
- 5-FOA, 5-fluoroorotic acid
- CFU, colony forming unit
- CRISPR
- CRISPR/Cas, Clustered Regularly-Interspaced Short Palindromic Repeat/CRISPR associated
- Cas9
- Cas9n, nickase Cas9
- Clostridium thermocellum
- HDR, homology-directed repair
- HR, homologous recombination
- PAM, protospacer adjacent motif
- RNP, Cas9-sgRNA ribonucleoprotein
- Thermophilic recombineering
- Tm, thiamphenicol
- Type I–B
- sgRNA, single guide RNA
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Affiliation(s)
- Julie E. Walker
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80303, USA
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Anthony A. Lanahan
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Tianyong Zheng
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Camilo Toruno
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Lee R. Lynd
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Jeffrey C. Cameron
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80303, USA
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Department of Biochemistry, University of Colorado, Boulder, CO, 80303, USA
- National Renewable Energy Laboratory, Biosciences Center, Golden, USA
| | - Daniel G. Olson
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Carrie A. Eckert
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, 80303, USA
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
- National Renewable Energy Laboratory, Biosciences Center, Golden, USA
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Abstract
Understanding the underlying biology of pathogens is essential to develop novel treatment options. To drive this understanding, genetic tools are essential. In recent years, the genetic toolbox available to Clostridioides difficile researchers has expanded significantly but still requires the conjugal transfer of DNA from a donor strain into C. difficile. Here we describe an electroporation-based transformation protocol that was effective at introducing existing genetic tools into different C. difficile strains. An important risk factor for acquiring Clostridioides difficile infection is antibiotic use. Therefore, a detailed knowledge of the physiology and the virulence factors can help drive the development of new diagnostic tools and nonantibiotic therapeutic agents to combat these organisms. Several genetic systems are available to study C. difficile in the laboratory environment, and all rely on stably replicating or segregationally unstable plasmids. Currently, the transfer of plasmids into C. difficile can only be performed by conjugation using Escherichia coli or Bacillus subtilis as conjugal donors. Here we report a method to introduce plasmid DNA into C. difficile using electroporation and test factors that might contribute to higher transformation efficiencies: osmolyte used to stabilize weakened cells, DNA concentration, and recovery time postelectroporation. Depending on the C. difficile strain and plasmid used, this transformation protocol achieves between 20 and 200 colonies per microgram of DNA and is mostly influenced by the recovery time postelectroporation. Based on our findings, we recommend that each strain be tested for the optimum recovery time in each lab. IMPORTANCE Understanding the underlying biology of pathogens is essential to develop novel treatment options. To drive this understanding, genetic tools are essential. In recent years, the genetic toolbox available to Clostridioides difficile researchers has expanded significantly but still requires the conjugal transfer of DNA from a donor strain into C. difficile. Here we describe an electroporation-based transformation protocol that was effective at introducing existing genetic tools into different C. difficile strains.
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