1
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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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2
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Schwarz TS, Schreiber SS, Marchfelder A. CRISPR Interference as a Tool to Repress Gene Expression in Haloferax volcanii. Methods Mol Biol 2022; 2522:57-85. [PMID: 36125743 DOI: 10.1007/978-1-0716-2445-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
To date, a plethora of tools for molecular biology have been developed on the basis of the CRISPR-Cas system. Almost all use the class 2 systems since here the setup is the simplest with only one protein and one guide RNA, allowing for easy transfer to and expression in other organisms. However, the CRISPR-Cas components harnessed for applications are derived from mesophilic bacteria and are not optimal for use in extremophilic archaea.Here, we describe the application of an endogenous CRISPR-Cas system as a tool for silencing gene expression in a halophilic archaeon. Haloferax volcanii has a CRISPR-Cas system of subtype I-B, which can be easily used to repress the transcription of endogenous genes, allowing to study the effects of their depletion. This article gives a step-by-step introduction on how to use the implemented system for any gene of interest in Haloferax volcanii. The concept of CRISPRi described here for Haloferax can be transferred to any other archaeon, that is genetically tractable and has an endogenous CRISPR-Cas I systems.
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3
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Guzmán NM, Esquerra-Ruvira B, Mojica FJM. Digging into the lesser-known aspects of CRISPR biology. Int Microbiol 2021; 24:473-498. [PMID: 34487299 PMCID: PMC8616872 DOI: 10.1007/s10123-021-00208-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/26/2022]
Abstract
A long time has passed since regularly interspaced DNA repeats were discovered in prokaryotes. Today, those enigmatic repetitive elements termed clustered regularly interspaced short palindromic repeats (CRISPR) are acknowledged as an emblematic part of multicomponent CRISPR-Cas (CRISPR associated) systems. These systems are involved in a variety of roles in bacteria and archaea, notably, that of conferring protection against transmissible genetic elements through an adaptive immune-like response. This review summarises the present knowledge on the diversity, molecular mechanisms and biology of CRISPR-Cas. We pay special attention to the most recent findings related to the determinants and consequences of CRISPR-Cas activity. Research on the basic features of these systems illustrates how instrumental the study of prokaryotes is for understanding biology in general, ultimately providing valuable tools for diverse fields and fuelling research beyond the mainstream.
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Affiliation(s)
- Noemí M Guzmán
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Belén Esquerra-Ruvira
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Francisco J M Mojica
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain. .,Instituto Multidisciplinar para el Estudio del Medio, Universidad de Alicante, Alicante, Spain.
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4
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Abstract
Transcriptional regulators that integrate cellular and environmental signals to control cell division are well known in bacteria and eukaryotes, but their existence is poorly understood in archaea. We identified a conserved gene (cdrS) that encodes a small protein and is highly transcribed in the model archaeon Haloferax volcanii. The cdrS gene could not be deleted, but CRISPR interference (CRISPRi)-mediated repression of the cdrS gene caused slow growth and cell division defects and changed the expression of multiple genes and their products associated with cell division, protein degradation, and metabolism. Consistent with this complex regulatory network, overexpression of cdrS inhibited cell division, whereas overexpression of the operon encoding both CdrS and a tubulin-like cell division protein (FtsZ2) stimulated division. Chromatin immunoprecipitation-DNA sequencing (ChIP-Seq) identified 18 DNA-binding sites of the CdrS protein, including one upstream of the promoter for a cell division gene, ftsZ1, and another upstream of the essential gene dacZ, encoding diadenylate cyclase involved in c-di-AMP signaling, which is implicated in the regulation of cell division. These findings suggest that CdrS is a transcription factor that plays a central role in a regulatory network coordinating metabolism and cell division. IMPORTANCE Cell division is a central mechanism of life and is essential for growth and development. Members of the Bacteria and Eukarya have different mechanisms for cell division, which have been studied in detail. In contrast, cell division in members of the Archaea is still understudied, and its regulation is poorly understood. Interestingly, different cell division machineries appear in members of the Archaea, with the Euryarchaeota using a cell division apparatus based on the tubulin-like cytoskeletal protein FtsZ, as in bacteria. Here, we identify the small protein CdrS as essential for survival and a central regulator of cell division in the euryarchaeon Haloferax volcanii. CdrS also appears to coordinate other cellular pathways, including synthesis of signaling molecules and protein degradation. Our results show that CdrS plays a sophisticated role in cell division, including regulation of numerous associated genes. These findings are expected to initiate investigations into conditional regulation of division in archaea.
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5
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Osakabe K, Wada N, Murakami E, Miyashita N, Osakabe Y. Genome editing in mammalian cells using the CRISPR type I-D nuclease. Nucleic Acids Res 2021; 49:6347-6363. [PMID: 34076237 PMCID: PMC8216271 DOI: 10.1093/nar/gkab348] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 04/15/2021] [Accepted: 05/20/2021] [Indexed: 12/26/2022] Open
Abstract
Adoption of CRISPR-Cas systems, such as CRISPR-Cas9 and CRISPR-Cas12a, has revolutionized genome engineering in recent years; however, application of genome editing with CRISPR type I-the most abundant CRISPR system in bacteria-remains less developed. Type I systems, such as type I-E, and I-F, comprise the CRISPR-associated complex for antiviral defense ('Cascade': Cas5, Cas6, Cas7, Cas8 and the small subunit) and Cas3, which degrades the target DNA; in contrast, for the sub-type CRISPR-Cas type I-D, which lacks a typical Cas3 nuclease in its CRISPR locus, the mechanism of target DNA degradation remains unknown. Here, we found that Cas10d is a functional nuclease in the type I-D system, performing the role played by Cas3 in other CRISPR-Cas type I systems. The type I-D system can be used for targeted mutagenesis of genomic DNA in human cells, directing both bi-directional long-range deletions and short insertions/deletions. Our findings suggest the CRISPR-Cas type I-D system as a unique effector pathway in CRISPR that can be repurposed for genome engineering in eukaryotic cells.
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Affiliation(s)
- Keishi Osakabe
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Naoki Wada
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Emi Murakami
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
| | - Naoyuki Miyashita
- Department of Computational Systems Biology, Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Wakayama 649-6493, Japan
| | - Yuriko Osakabe
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Tokushima 770-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502, Japan
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6
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Schwarz TS, Berkemer SJ, Bernhart SH, Weiß M, Ferreira-Cerca S, Stadler PF, Marchfelder A. Splicing Endonuclease Is an Important Player in rRNA and tRNA Maturation in Archaea. Front Microbiol 2020; 11:594838. [PMID: 33329479 PMCID: PMC7714728 DOI: 10.3389/fmicb.2020.594838] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
In all three domains of life, tRNA genes contain introns that must be removed to yield functional tRNA. In archaea and eukarya, the first step of this process is catalyzed by a splicing endonuclease. The consensus structure recognized by the splicing endonuclease is a bulge-helix-bulge (BHB) motif which is also found in rRNA precursors. So far, a systematic analysis to identify all biological substrates of the splicing endonuclease has not been carried out. In this study, we employed CRISPRi to repress expression of the splicing endonuclease in the archaeon Haloferax volcanii to identify all substrates of this enzyme. Expression of the splicing endonuclease was reduced to 1% of its normal level, resulting in a significant extension of lag phase in H. volcanii growth. In the repression strain, 41 genes were down-regulated and 102 were up-regulated. As an additional approach in identifying new substrates of the splicing endonuclease, we isolated and sequenced circular RNAs, which identified excised introns removed from tRNA and rRNA precursors as well as from the 5' UTR of the gene HVO_1309. In vitro processing assays showed that the BHB sites in the 5' UTR of HVO_1309 and in a 16S rRNA-like precursor are processed by the recombinant splicing endonuclease. The splicing endonuclease is therefore an important player in RNA maturation in archaea.
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Affiliation(s)
| | - Sarah J Berkemer
- Bioinformatics, Department of Computer Science, Leipzig University, Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany.,Competence Center for Scalable Data Services and Solutions, Leipzig University, Leipzig, Germany
| | - Stephan H Bernhart
- Bioinformatics, Department of Computer Science, Leipzig University, Leipzig, Germany.,Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Matthias Weiß
- Regensburg Center for Biochemistry, Biochemistry III - Institute of Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Regensburg Center for Biochemistry, Biochemistry III - Institute of Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Peter F Stadler
- Bioinformatics, Department of Computer Science, Leipzig University, Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany.,Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Research Center for Civilization Diseases, Leipzig University, Leipzig, Germany.,Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia.,Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.,Center for RNA in Technology and Health, University of Copenhagen, Frederiksberg, Denmark.,Santa Fe Institute, Santa Fe, NM, United States
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7
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Stachler AE, Wörtz J, Alkhnbashi OS, Turgeman-Grott I, Smith R, Allers T, Backofen R, Gophna U, Marchfelder A. Adaptation induced by self-targeting in a type I-B CRISPR-Cas system. J Biol Chem 2020; 295:13502-13515. [PMID: 32723866 PMCID: PMC7521656 DOI: 10.1074/jbc.ra120.014030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/15/2020] [Indexed: 11/06/2022] Open
Abstract
Haloferax volcanii is, to our knowledge, the only prokaryote known to tolerate CRISPR-Cas-mediated damage to its genome in the WT background; the resulting cleavage of the genome is repaired by homologous recombination restoring the WT version. In mutant Haloferax strains with enhanced self-targeting, cell fitness decreases and microhomology-mediated end joining becomes active, generating deletions in the targeted gene. Here we use self-targeting to investigate adaptation in H. volcanii CRISPR-Cas type I-B. We show that self-targeting and genome breakage events that are induced by self-targeting, such as those catalyzed by active transposases, can generate DNA fragments that are used by the CRISPR-Cas adaptation machinery for integration into the CRISPR loci. Low cellular concentrations of self-targeting crRNAs resulted in acquisition of large numbers of spacers originating from the entire genomic DNA. In contrast, high concentrations of self-targeting crRNAs resulted in lower acquisition that was mostly centered on the targeting site. Furthermore, we observed naïve spacer acquisition at a low level in WT Haloferax cells and with higher efficiency upon overexpression of the Cas proteins Cas1, Cas2, and Cas4. Taken together, these findings indicate that naïve adaptation is a regulated process in H. volcanii that operates at low basal levels and is induced by DNA breaks.
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Affiliation(s)
| | | | - Omer S Alkhnbashi
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Israela Turgeman-Grott
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Rachel Smith
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Uri Gophna
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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8
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Zheng Y, Han J, Wang B, Hu X, Li R, Shen W, Ma X, Ma L, Yi L, Yang S, Peng W. Characterization and repurposing of the endogenous Type I-F CRISPR-Cas system of Zymomonas mobilis for genome engineering. Nucleic Acids Res 2020; 47:11461-11475. [PMID: 31647102 PMCID: PMC6868425 DOI: 10.1093/nar/gkz940] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/05/2019] [Accepted: 10/09/2019] [Indexed: 12/19/2022] Open
Abstract
Application of CRISPR-based technologies in non-model microorganisms is currently very limited. Here, we reported efficient genome engineering of an important industrial microorganism, Zymomonas mobilis, by repurposing the endogenous Type I-F CRISPR–Cas system upon its functional characterization. This toolkit included a series of genome engineering plasmids, each carrying an artificial self-targeting CRISPR and a donor DNA for the recovery of recombinants. Through this toolkit, various genome engineering purposes were efficiently achieved, including knockout of ZMO0038 (100% efficiency), cas2/3 (100%), and a genomic fragment of >10 kb (50%), replacement of cas2/3 with mCherry gene (100%), in situ nucleotide substitution (100%) and His-tagging of ZMO0038 (100%), and multiplex gene deletion (18.75%) upon optimal donor size determination. Additionally, the Type I-F system was further applied for CRISPRi upon Cas2/3 depletion, which has been demonstrated to successfully silence the chromosomally integrated mCherry gene with its fluorescence intensity reduced by up to 88%. Moreover, we demonstrated that genome engineering efficiency could be improved under a restriction–modification (R–M) deficient background, suggesting the perturbance of genome editing by other co-existing DNA targeting modules such as the R–M system. This study might shed light on exploiting and improving CRISPR–Cas systems in other microorganisms for genome editing and metabolic engineering practices.
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Affiliation(s)
- Yanli Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Jiamei Han
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Baiyang Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Xiaoyun Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Runxia Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Wei Shen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Xiangdong Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Lixin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Li Yi
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
| | - Wenfang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Engineering Research Center for Bio-enzyme Catalysis, Environmental Microbial Technology Center of Hubei Province, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, School of Life Sciences, Hubei University, Wuhan 430062, P.R. China
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9
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Zheng Y, Li J, Wang B, Han J, Hao Y, Wang S, Ma X, Yang S, Ma L, Yi L, Peng W. Endogenous Type I CRISPR-Cas: From Foreign DNA Defense to Prokaryotic Engineering. Front Bioeng Biotechnol 2020; 8:62. [PMID: 32195227 PMCID: PMC7064716 DOI: 10.3389/fbioe.2020.00062] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/24/2020] [Indexed: 12/18/2022] Open
Abstract
Establishment of production platforms through prokaryotic engineering in microbial organisms would be one of the most efficient means for chemicals, protein, and biofuels production. Despite the fact that CRISPR (clustered regularly interspaced short palindromic repeats)–based technologies have readily emerged as powerful and versatile tools for genetic manipulations, their applications are generally limited in prokaryotes, possibly owing to the large size and severe cytotoxicity of the heterogeneous Cas (CRISPR-associated) effector. Nevertheless, the rich natural occurrence of CRISPR-Cas systems in many bacteria and most archaea holds great potential for endogenous CRISPR-based prokaryotic engineering. The endogenous CRISPR-Cas systems, with type I systems that constitute the most abundant and diverse group, would be repurposed as genetic manipulation tools once they are identified and characterized as functional in their native hosts. This article reviews the major progress made in understanding the mechanisms of invading DNA immunity by type I CRISPR-Cas and summarizes the practical applications of endogenous type I CRISPR-based toolkits for prokaryotic engineering.
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Affiliation(s)
- Yanli Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Jie Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Baiyang Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Jiamei Han
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Yile Hao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Shengchen Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Xiangdong Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Lixin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Li Yi
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
| | - Wenfang Peng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, China
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10
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Behler J, Hess WR. Approaches to study CRISPR RNA biogenesis and the key players involved. Methods 2020; 172:12-26. [PMID: 31325492 DOI: 10.1016/j.ymeth.2019.07.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/29/2019] [Accepted: 07/15/2019] [Indexed: 12/26/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins provide an inheritable and adaptive immune system against phages and foreign genetic elements in many bacteria and archaea. The three stages of CRISPR-Cas immunity comprise adaptation, CRISPR RNA (crRNA) biogenesis and interference. The maturation of the pre-crRNA into mature crRNAs, short guide RNAs that target invading nucleic acids, is crucial for the functionality of CRISPR-Cas defense systems. Mature crRNAs assemble with Cas proteins into the ribonucleoprotein (RNP) effector complex and guide the Cas nucleases to the cognate foreign DNA or RNA target. Experimental approaches to characterize these crRNAs, the specific steps toward their maturation and the involved factors, include RNA-seq analyses, enzyme assays, methods such as cryo-electron microscopy, the crystallization of proteins, or UV-induced protein-RNA crosslinking coupled to mass spectrometry analysis. Complex and multiple interactions exist between CRISPR-cas-encoded specific riboendonucleases such as Cas6, Cas5d and Csf5, endonucleases with dual functions in maturation and interference such as the enzymes of the Cas12 and Cas13 families, and nucleases belonging to the cell's degradosome such as RNase E, PNPase and RNase J, both in the maturation as well as in interference. The results of these studies have yielded a picture of unprecedented diversity of sequences, enzymes and biochemical mechanisms.
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Affiliation(s)
- Juliane Behler
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany; University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104 Freiburg, Germany.
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11
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Stachler AE, Schwarz TS, Schreiber S, Marchfelder A. CRISPRi as an efficient tool for gene repression in archaea. Methods 2020; 172:76-85. [DOI: 10.1016/j.ymeth.2019.05.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/20/2019] [Accepted: 05/27/2019] [Indexed: 11/30/2022] Open
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12
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O'Connell MR. Molecular Mechanisms of RNA Targeting by Cas13-containing Type VI CRISPR-Cas Systems. J Mol Biol 2019; 431:66-87. [PMID: 29940185 DOI: 10.1016/j.jmb.2018.06.029] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022]
Abstract
Prokaryotic adaptive immune systems use Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) and CRISPR-associated (Cas) proteins for RNA-guided cleavage of foreign genetic elements. The focus of this review, Type VI CRISPR-Cas systems, contain a single protein, Cas13 (formerly C2c2) that when assembled with a CRISPR RNA (crRNA) forms a crRNA-guided RNA-targeting effector complex. Type VI CRISPR-Cas systems can be divided into four subtypes (A-D) based on Cas13 phylogeny. All Cas13 proteins studied to date possess two enzymatically distinct ribonuclease activities that are required for optimal interference. One RNase is responsible for pre-crRNA processing to form mature Type VI interference complexes, while the other RNase activity provided by the two Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) domains, is required for degradation of target-RNA during viral interference. In this review, I will compare and contrast what is known about the molecular architecture and behavior of Type VI (A-D) CRISPR-Cas13 interference complexes, how this allows them to carry out their RNA-targeting function, how Type VI accessory proteins are able to modulate Cas13 activity, and how together all of these features have led to the rapid development of a range of RNA-targeting applications. Throughout I will also discuss some of the outstanding questions regarding Cas13's molecular behavior, and its role in bacterial adaptive immunity and RNA-targeting applications.
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Affiliation(s)
- Mitchell R O'Connell
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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Maier LK, Stachler AE, Brendel J, Stoll B, Fischer S, Haas KA, Schwarz TS, Alkhnbashi OS, Sharma K, Urlaub H, Backofen R, Gophna U, Marchfelder A. The nuts and bolts of the Haloferax CRISPR-Cas system I-B. RNA Biol 2018; 16:469-480. [PMID: 29649958 PMCID: PMC6546412 DOI: 10.1080/15476286.2018.1460994] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Invading genetic elements pose a constant threat to prokaryotic survival, requiring an effective defence. Eleven years ago, the arsenal of known defence mechanisms was expanded by the discovery of the CRISPR-Cas system. Although CRISPR-Cas is present in the majority of archaea, research often focuses on bacterial models. Here, we provide a perspective based on insights gained studying CRISPR-Cas system I-B of the archaeon Haloferax volcanii. The system relies on more than 50 different crRNAs, whose stability and maintenance critically depend on the proteins Cas5 and Cas7, which bind the crRNA and form the Cascade complex. The interference machinery requires a seed sequence and can interact with multiple PAM sequences. H. volcanii stands out as the first example of an organism that can tolerate autoimmunity via the CRISPR-Cas system while maintaining a constitutively active system. In addition, the H. volcanii system was successfully developed into a tool for gene regulation.
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Affiliation(s)
| | | | | | | | | | - Karina A Haas
- a Biology II, Ulm University , Ulm , Germany.,b Microbiology and Biotechnology, Ulm University , Ulm , Germany
| | | | - Omer S Alkhnbashi
- c Freiburg Bioinformatics Group, Department of Computer Science , University of Freiburg , Georges-Köhler-Allee 106, Freiburg , Germany
| | - Kundan Sharma
- e Max Planck Institute of Biophysical Chemistry , Am Faßberg 11, Göttingen , Germany.,f Ludwig Institute for Cancer Research, University of Oxford , Oxford , United Kingdom
| | - Henning Urlaub
- e Max Planck Institute of Biophysical Chemistry , Am Faßberg 11, Göttingen , Germany.,g Institute for Clinical Chemistry, University Medical Center Göttingen , Robert Koch Straße 10, Göttingen , Germany
| | - Rolf Backofen
- c Freiburg Bioinformatics Group, Department of Computer Science , University of Freiburg , Georges-Köhler-Allee 106, Freiburg , Germany.,d Centre for Biological Signalling Studies (BIOSS), Cluster of Excellence, University of Freiburg , Germany
| | - Uri Gophna
- h School of Molecular Cell Biology & Biotechnology, George S. Wise, Faculty of Life Sciences, Tel Aviv University , Tel Aviv , Israel
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Cheng F, Gong L, Zhao D, Yang H, Zhou J, Li M, Xiang H. Harnessing the native type I-B CRISPR-Cas for genome editing in a polyploid archaeon. J Genet Genomics 2017; 44:541-548. [DOI: 10.1016/j.jgg.2017.09.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 09/18/2017] [Accepted: 09/25/2017] [Indexed: 12/26/2022]
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15
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Stachler AE, Turgeman-Grott I, Shtifman-Segal E, Allers T, Marchfelder A, Gophna U. High tolerance to self-targeting of the genome by the endogenous CRISPR-Cas system in an archaeon. Nucleic Acids Res 2017; 45:5208-5216. [PMID: 28334774 PMCID: PMC5435918 DOI: 10.1093/nar/gkx150] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/01/2017] [Indexed: 12/20/2022] Open
Abstract
CRISPR-Cas systems allow bacteria and archaea to acquire sequence-specific immunity against selfish genetic elements such as viruses and plasmids, by specific degradation of invader DNA or RNA. However, this involves the risk of autoimmunity if immune memory against host DNA is mistakenly acquired. Such autoimmunity has been shown to be highly toxic in several bacteria and is believed to be one of the major costs of maintaining these defense systems. Here we generated an experimental system in which a non-essential gene, required for pigment production and the reddish colony color, is targeted by the CRISPR-Cas I-B system of the halophilic archaeon Haloferax volcanii. We show that under native conditions, where both the self-targeting and native crRNAs are expressed, self-targeting by CRISPR-Cas causes no reduction in transformation efficiency of the plasmid encoding the self-targeting crRNA. Furthermore, under such conditions, no effect on organismal growth rate or loss of the reddish colony phenotype due to mutations in the targeted region could be observed. In contrast, in cells deleted for the pre-crRNA processing gene cas6, where only the self-targeting crRNA exists as mature crRNA, self-targeting leads to moderate toxicity and the emergence of deletion mutants. Sequencing of the deletions caused by CRISPR-Cas self targeting indicated DNA repair via microhomology-mediated end joining.
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Affiliation(s)
| | - Israela Turgeman-Grott
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978-01, Israel
| | - Ella Shtifman-Segal
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978-01, Israel
| | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | | | - Uri Gophna
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978-01, Israel
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Li M, Gong L, Zhao D, Zhou J, Xiang H. The spacer size of I-B CRISPR is modulated by the terminal sequence of the protospacer. Nucleic Acids Res 2017; 45:4642-4654. [PMID: 28379481 PMCID: PMC5416893 DOI: 10.1093/nar/gkx229] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/25/2017] [Indexed: 12/29/2022] Open
Abstract
Prokaryotes memorize invader information by incorporating alien DNA as spacers into CRISPR arrays. Although the spacer size has been suggested to be predefined by the architecture of the acquisition complex, there is usually an unexpected heterogeneity. Here, we explored the causes of this heterogeneity in Haloarcula hispanica I-B CRISPR. High-throughput sequencing following adaptation assays demonstrated significant size variation among 37 957 new spacers, which appeared to be sequence-dependent. Consistently, the third nucleotide at the spacer 3΄-end (PAM-distal end) showed an evident bias for cytosine and mutating this cytosine in the protospacer sequence could change the final spacer size. In addition, slippage of the 5΄-end (PAM-end), which contributed to most of the observed PAM (protospacer adjacent motif) inaccuracy, also tended to change the spacer size. We propose that both ends of the PAM-protospacer sequence should exhibit nucleotide selectivity (with different stringencies), which fine-tunes the structural ruler, to a certain extent, to specify the spacer size.
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Affiliation(s)
- Ming Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Luyao Gong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dahe Zhao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jian Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
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RNA Targeting by Functionally Orthogonal Type VI-A CRISPR-Cas Enzymes. Mol Cell 2017; 66:373-383.e3. [PMID: 28475872 PMCID: PMC5999320 DOI: 10.1016/j.molcel.2017.04.008] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/21/2017] [Accepted: 04/10/2017] [Indexed: 12/26/2022]
Abstract
CRISPR adaptive immunity pathways protect prokaryotic cells against foreign nucleic acids using CRISPR RNA (crRNA)-guided nucleases. In type VI-A CRISPR-Cas systems, the signature protein Cas13a (formerly C2c2) contains two separate ribonuclease activities that catalyze crRNA maturation and ssRNA degradation. The Cas13a protein family occurs across different bacterial phyla and varies widely in both protein sequence and corresponding crRNA sequence conservation. Although grouped phylogenetically together, we show that the Cas13a enzyme family comprises two distinct functional groups that recognize orthogonal sets of crRNAs and possess different ssRNA cleavage specificities. These functional distinctions could not be bioinformatically predicted, suggesting more subtle co-evolution of Cas13a enzymes. Additionally, we find that Cas13a pre-crRNA processing is not essential for ssRNA cleavage, although it enhances ssRNA targeting for crRNAs encoded internally within the CRISPR array. We define two Cas13a protein subfamilies that can operate in parallel for RNA detection both in bacteria and for diagnostic applications.
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18
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Fragmentation of the CRISPR-Cas Type I-B signature protein Cas8b. Biochim Biophys Acta Gen Subj 2017; 1861:2993-3000. [PMID: 28238733 DOI: 10.1016/j.bbagen.2017.02.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/10/2017] [Accepted: 02/16/2017] [Indexed: 01/19/2023]
Abstract
BACKGROUND CRISPR arrays are transcribed into long precursor RNA species, which are further processed into mature CRISPR RNAs (crRNAs). Cas proteins utilize these crRNAs, which contain spacer sequences that can be derived from mobile genetic elements, to mediate immunity during a reoccurring virus infection. Type I CRISPR-Cas systems are defined by the presence of different Cascade interference complexes containing large and small subunits that play major roles during target DNA selection. METHODS Here, we produce the protein and crRNA components of the Type I-B CRISPR-Cas complex of Clostridium thermocellum and Methanococcus maripaludis. The C. thermocellum Cascade complexes were reconstituted and analyzed via size-exclusion chromatography. Activity of the heterologous M. maripaludis CRISPR-Cas system was followed using phage lambda plaques assays. RESULTS The reconstituted Type-I-B Cascade complex contains Cas7, Cas5, Cas6b and the large subunit Cas8b. Cas6b can be omitted from the reconstitution protocol. The large subunit Cas8b was found to be represented by two tightly associated protein fragments and a small C-terminal Cas8b segment was identified in recombinant complexes and C. thermocellum cell lysate. CONCLUSIONS Production of Cas8b generates a small C-terminal fragment, which is suggested to fulfill the role of the missing small subunit. A heterologous, synthetic M. maripaludis Type I-B system is active in E. coli against phage lambda, highlighting a potential for genome editing using endogenous Type-I-B CRISPR-Cas machineries. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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19
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Stachler AE, Marchfelder A. Gene Repression in Haloarchaea Using the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-Cas I-B System. J Biol Chem 2016; 291:15226-42. [PMID: 27226589 PMCID: PMC4946936 DOI: 10.1074/jbc.m116.724062] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Indexed: 12/20/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system is used by bacteria and archaea to fend off foreign genetic elements. Since its discovery it has been developed into numerous applications like genome editing and regulation of transcription in eukaryotes and bacteria. For archaea currently no tools for transcriptional repression exist. Because molecular biology analyses in archaea become more and more widespread such a tool is vital for investigating the biological function of essential genes in archaea. Here we use the model archaeon Haloferax volcanii to demonstrate that its endogenous CRISPR-Cas system I-B can be harnessed to repress gene expression in archaea. Deletion of cas3 and cas6b genes results in efficient repression of transcription. crRNAs targeting the promoter region reduced transcript levels down to 8%. crRNAs targeting the reading frame have only slight impact on transcription. crRNAs that target the coding strand repress expression only down to 88%, whereas crRNAs targeting the template strand repress expression down to 8%. Repression of an essential gene results in reduction of transcription levels down to 22%. Targeting efficiencies can be enhanced by expressing a catalytically inactive Cas3 mutant. Genes can be targeted on plasmids or on the chromosome, they can be monocistronic or part of a polycistronic operon.
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Affiliation(s)
| | - Anita Marchfelder
- From the Department of Biology II, Ulm University, 89069 Ulm, Germany
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20
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Semenova E, Kuznedelov K, Datsenko KA, Boudry PM, Savitskaya EE, Medvedeva S, Beloglazova N, Logacheva M, Yakunin AF, Severinov K. The Cas6e ribonuclease is not required for interference and adaptation by the E. coli type I-E CRISPR-Cas system. Nucleic Acids Res 2015; 43:6049-61. [PMID: 26013814 PMCID: PMC4499155 DOI: 10.1093/nar/gkv546] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/12/2015] [Indexed: 11/30/2022] Open
Abstract
CRISPR-Cas are small RNA-based adaptive prokaryotic immunity systems protecting cells from foreign DNA or RNA. Type I CRISPR-Cas systems are composed of a multiprotein complex (Cascade) that, when bound to CRISPR RNA (crRNA), can recognize double-stranded DNA targets and recruit the Cas3 nuclease to destroy target-containing DNA. In the Escherichia coli type I-E CRISPR-Cas system, crRNAs are generated upon transcription of CRISPR arrays consisting of multiple palindromic repeats and intervening spacers through the function of Cas6e endoribonuclease, which cleaves at specific positions of repeat sequences of the CRISPR array transcript. Cas6e is also a component of Cascade. Here, we show that when mature unit-sized crRNAs are provided in a Cas6e-independent manner by transcription termination, the CRISPR-Cas system can function without Cas6e. The results should allow facile interrogation of various targets by type I-E CRISPR-Cas system in E. coli using unit-sized crRNAs generated by transcription.
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Affiliation(s)
- Ekaterina Semenova
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Konstantin Kuznedelov
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Kirill A Datsenko
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Pierre M Boudry
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA Laboratoire Pathogenèse des Bactéries Anaérobies, Institut Pasteur, Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Ekaterina E Savitskaya
- Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia
| | - Sofia Medvedeva
- Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Natalia Beloglazova
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Maria Logacheva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Konstantin Severinov
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia Institute of Molecular Genetics, Russian Academy of Sciences, Moscow 123182, Russia Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
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Abstract
CRISPR (clustered regularly interspaced short palindromic repeat) systems provide bacteria and archaea with adaptive immunity to repel invasive genetic elements. Type I systems use 'cascade' [CRISPR-associated (Cas) complex for antiviral defence] ribonucleoprotein complexes to target invader DNA, by base pairing CRISPR RNA (crRNA) to protospacers. Cascade identifies PAMs (protospacer adjacent motifs) on invader DNA, triggering R-loop formation and subsequent DNA degradation by Cas3. Cas8 is a candidate PAM recognition factor in some cascades. We analysed Cas8 homologues from type IB CRISPR systems in archaea Haloferax volcanii (Hvo) and Methanothermobacter thermautotrophicus (Mth). Cas8 was essential for CRISPR interference in Hvo and purified Mth Cas8 protein responded to PAM sequence when binding to nucleic acids. Cas8 interacted physically with Cas5-Cas7-crRNA complex, stimulating binding to PAM containing substrates. Mutation of conserved Cas8 amino acid residues abolished interference in vivo and altered catalytic activity of Cas8 protein in vitro. This is experimental evidence that Cas8 is important for targeting Cascade to invader DNA.
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Maier LK, Dyall-Smith M, Marchfelder A. The Adaptive Immune System of Haloferax volcanii. Life (Basel) 2015; 5:521-37. [PMID: 25692903 PMCID: PMC4390866 DOI: 10.3390/life5010521] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/03/2015] [Indexed: 11/30/2022] Open
Abstract
To fight off invading genetic elements, prokaryotes have developed an elaborate defence system that is both adaptable and heritable—the CRISPR-Cas system (CRISPR is short for: clustered regularly interspaced short palindromic repeats and Cas: CRISPR associated). Comprised of proteins and multiple small RNAs, this prokaryotic defence system is present in 90% of archaeal and 40% of bacterial species, and enables foreign intruders to be eliminated in a sequence-specific manner. There are three major types (I–III) and at least 14 subtypes of this system, with only some of the subtypes having been analysed in detail, and many aspects of the defence reaction remaining to be elucidated. Few archaeal examples have so far been analysed. Here we summarize the characteristics of the CRISPR-Cas system of Haloferax volcanii, an extremely halophilic archaeon originally isolated from the Dead Sea. It carries a single CRISPR-Cas system of type I-B, with a Cascade like complex composed of Cas proteins Cas5, Cas6b and Cas7. Cas6b is essential for CRISPR RNA (crRNA) maturation but is otherwise not required for the defence reaction. A systematic search revealed that six protospacer adjacent motif (PAM) sequences are recognised by the Haloferax defence system. For successful invader recognition, a non-contiguous seed sequence of 10 base-pairs between the crRNA and the invader is required.
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Affiliation(s)
| | - Mike Dyall-Smith
- School of Biomedical Sciences, Charles Sturt University, 2650 NSW, Australia.
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