1
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Wang S, Yang R, Song M, Li J, Zhou Y, Dai C, Song T. Current understanding of the role of DDX21 in orchestrating gene expression in health and diseases. Life Sci 2024; 349:122716. [PMID: 38762067 DOI: 10.1016/j.lfs.2024.122716] [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: 01/30/2024] [Revised: 04/30/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
RNA helicases are involved in almost all biological events, and the DDXs family is one of the largest subfamilies of RNA helicases. Recently, studies have reported that RNA helicase DDX21 is involved in several biological events, specifically in orchestrating gene expression. Hence, in this review, we provide a comprehensive overview of the function of DDX21 in health and diseases. In the genome, DDX21 contributes to genome stability by promoting DNA damage repair and resolving R-loops. It also facilitates transcriptional regulation by directly binding to promoter regions, interacting with transcription factors, and enhancing transcription through non-coding RNA. Moreover, DDX21 is involved in various RNA metabolism such as RNA processing, translation, and decay. Interestingly, the activity and function of DDX21 are regulated by post-translational modifications, which affect the localization and degradation of DDX21. Except for its role of RNA helicase, DDX21 also acts as a non-enzymatic function in unwinding RNA, regulating transcriptional modifications and promoting transcription. Next, we discuss the potential application of DDX21 as a clinical predictor for diseases, which may facilitate providing novel pharmacological targets for molecular therapy.
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Affiliation(s)
- Shaoshuai Wang
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ruiqi Yang
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mengzhen Song
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jia Li
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; City of Hope Medical Center, Duarte, CA 91010, USA; Division of Stem Cell Biology Research, Department of Developmental and Stem Cell Biology, Beckman Research Institute of City of Hope, 1500 E. Duarte Rd, Duarte, CA 91010, USA
| | - Yanrong Zhou
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Chen Dai
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan 430030, China.
| | - Tongxing Song
- College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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2
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Yang S, Winstone L, Mondal S, Wu Y. Helicases in R-loop Formation and Resolution. J Biol Chem 2023; 299:105307. [PMID: 37778731 PMCID: PMC10641170 DOI: 10.1016/j.jbc.2023.105307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/21/2023] [Accepted: 09/23/2023] [Indexed: 10/03/2023] Open
Abstract
With the development and wide usage of CRISPR technology, the presence of R-loop structures, which consist of an RNA-DNA hybrid and a displaced single-strand (ss) DNA, has become well accepted. R-loop structures have been implicated in a variety of circumstances and play critical roles in the metabolism of nucleic acid and relevant biological processes, including transcription, DNA repair, and telomere maintenance. Helicases are enzymes that use an ATP-driven motor force to unwind double-strand (ds) DNA, dsRNA, or RNA-DNA hybrids. Additionally, certain helicases have strand-annealing activity. Thus, helicases possess unique positions for R-loop biogenesis: they utilize their strand-annealing activity to promote the hybridization of RNA to DNA, leading to the formation of R-loops; conversely, they utilize their unwinding activity to separate RNA-DNA hybrids and resolve R-loops. Indeed, numerous helicases such as senataxin (SETX), Aquarius (AQR), WRN, BLM, RTEL1, PIF1, FANCM, ATRX (alpha-thalassemia/mental retardation, X-linked), CasDinG, and several DEAD/H-box proteins are reported to resolve R-loops; while other helicases, such as Cas3 and UPF1, are reported to stimulate R-loop formation. Moreover, helicases like DDX1, DDX17, and DHX9 have been identified in both R-loop formation and resolution. In this review, we will summarize the latest understandings regarding the roles of helicases in R-loop metabolism. Additionally, we will highlight challenges associated with drug discovery in the context of targeting these R-loop helicases.
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Affiliation(s)
- Shizhuo Yang
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lacey Winstone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Sohaumn Mondal
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yuliang Wu
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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3
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A Tryptophan 'Gate' in the CRISPR-Cas3 Nuclease Controls ssDNA Entry into the Nuclease Site, That When Removed Results in Nuclease Hyperactivity. Int J Mol Sci 2021; 22:ijms22062848. [PMID: 33799639 PMCID: PMC8001533 DOI: 10.3390/ijms22062848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022] Open
Abstract
Cas3 is a ssDNA-targeting nuclease-helicase essential for class 1 prokaryotic CRISPR immunity systems, which has been utilized for genome editing in human cells. Cas3-DNA crystal structures show that ssDNA follows a pathway from helicase domains into a HD-nuclease active site, requiring protein conformational flexibility during DNA translocation. In genetic studies, we had noted that the efficacy of Cas3 in CRISPR immunity was drastically reduced when temperature was increased from 30 °C to 37 °C, caused by an unknown mechanism. Here, using E. coli Cas3 proteins, we show that reduced nuclease activity at higher temperature corresponds with measurable changes in protein structure. This effect of temperature on Cas3 was alleviated by changing a single highly conserved tryptophan residue (Trp-406) into an alanine. This Cas3W406A protein is a hyperactive nuclease that functions independently from temperature and from the interference effector module Cascade. Trp-406 is situated at the interface of Cas3 HD and RecA1 domains that is important for maneuvering DNA into the nuclease active site. Molecular dynamics simulations based on the experimental data showed temperature-induced changes in positioning of Trp-406 that either blocked or cleared the ssDNA pathway. We propose that Trp-406 forms a 'gate' for controlling Cas3 nuclease activity via access of ssDNA to the nuclease active site. The effect of temperature in these experiments may indicate allosteric control of Cas3 nuclease activity caused by changes in protein conformations. The hyperactive Cas3W406A protein may offer improved Cas3-based genetic editing in human cells.
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4
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Mechanistic insights into Lhr helicase function in DNA repair. Biochem J 2021; 477:2935-2947. [PMID: 32706021 PMCID: PMC7437997 DOI: 10.1042/bcj20200379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/23/2020] [Accepted: 07/23/2020] [Indexed: 12/16/2022]
Abstract
The DNA helicase Large helicase-related (Lhr) is present throughout archaea, including in the Asgard and Nanoarchaea, and has homologues in bacteria and eukaryotes. It is thought to function in DNA repair but in a context that is not known. Our data show that archaeal Lhr preferentially targets DNA replication fork structures. In a genetic assay, expression of archaeal Lhr gave a phenotype identical to the replication-coupled DNA repair enzymes Hel308 and RecQ. Purified archaeal Lhr preferentially unwound model forked DNA substrates compared with DNA duplexes, flaps and Holliday junctions, and unwound them with directionality. Single-molecule FRET measurements showed that binding of Lhr to a DNA fork causes ATP-independent distortion and base-pair melting at, or close to, the fork branchpoint. ATP-dependent directional translocation of Lhr resulted in fork DNA unwinding through the ‘parental’ DNA strands. Interaction of Lhr with replication forks in vivo and in vitro suggests that it contributes to DNA repair at stalled or broken DNA replication.
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5
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Garrett S, Shiimori M, Watts EA, Clark L, Graveley BR, Terns MP. Primed CRISPR DNA uptake in Pyrococcus furiosus. Nucleic Acids Res 2020; 48:6120-6135. [PMID: 32421777 PMCID: PMC7293040 DOI: 10.1093/nar/gkaa381] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 04/15/2020] [Accepted: 05/11/2020] [Indexed: 12/19/2022] Open
Abstract
CRISPR-Cas adaptive immune systems are used by prokaryotes to defend against invaders like viruses and other mobile genetic elements. Immune memories are stored in the form of 'spacers' which are short DNA sequences that are captured from invaders and added to the CRISPR array during a process called 'adaptation'. Spacers are transcribed and the resulting CRISPR (cr)RNAs assemble with different Cas proteins to form effector complexes that recognize matching nucleic acid and destroy it ('interference'). Adaptation can be 'naïve', i.e. independent of any existing spacer matches, or it can be 'primed', i.e. spurred by the crRNA-mediated detection of a complete or partial match to an invader sequence. Here we show that primed adaptation occurs in Pyrococcus furiosus. Although P. furiosus has three distinct CRISPR-Cas interference systems (I-B, I-A and III-B), only the I-B system and Cas3 were necessary for priming. Cas4, which is important for selection and processing of new spacers in naïve adaptation, was also essential for priming. Loss of either the I-B effector proteins or Cas3 reduced naïve adaptation. However, when Cas3 and all crRNP genes were deleted, uptake of correctly processed spacers was observed, indicating that none of these interference proteins are necessary for naïve adaptation.
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Affiliation(s)
- Sandra Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Masami Shiimori
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Elizabeth A Watts
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Landon Clark
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Michael P Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.,Department of Microbiology, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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6
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Radovčić M, Čulo A, Ivančić-Baće I. Cas3-stimulated runaway replication of modified ColE1 plasmids in Escherichia coli is temperature dependent. FEMS Microbiol Lett 2020; 366:5490330. [PMID: 31095294 DOI: 10.1093/femsle/fnz106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 05/14/2019] [Indexed: 12/15/2022] Open
Abstract
The clustered regularly interspersed short palindromic repeats (CRISPR)-Cas system constitutes an adaptive immunity system of prokaryotes against mobile genetic elements using a CRISPR RNA (crRNA)-mediated interference mechanism. In Type I CRISPR-Cas systems, crRNA guided by a Cascade complex recognises the matching target DNA and promotes an R-loop formation, RNA-DNA hybrid. The helicase-nuclease Cas3 protein is then recruited to the Cascade/R-loop complex where it nicks and degrades DNA. The Cas3 activity in CRISPR-Cas immunity is reduced in Δhns cells at 37°C for unknown reasons. Cas3 can also influence regulation of plasmid replication and promote uncontrolled ('runaway') replication of ColE1 plasmids independently of other CRISPR-Cas components, requiring only its helicase activity. In this work we wanted to test whether Cas3-stimulated uncontrolled plasmid replication is affected by the temperature in Δhns and/or ΔhtpG mutants. We found that Cas3-stimulated uncontrolled plasmid replication occurs only at 37°C, irrespective of the genotype of the analysed mutants, and dependent on Cas3 helicase function. We also found that plasmid replication was strongly reduced by the hns mutation at 30°C and that Cas3 could interfere with T4 phage replication at both incubation temperatures.
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Affiliation(s)
- Marin Radovčić
- Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Anja Čulo
- Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Ivana Ivančić-Baće
- Department of Biology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
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7
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Nimkar S, Anand B. Cas3/I-C mediated target DNA recognition and cleavage during CRISPR interference are independent of the composition and architecture of Cascade surveillance complex. Nucleic Acids Res 2020; 48:2486-2501. [PMID: 31980818 PMCID: PMC7049708 DOI: 10.1093/nar/gkz1218] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/17/2019] [Accepted: 01/22/2020] [Indexed: 12/26/2022] Open
Abstract
In type I CRISPR-Cas system, Cas3—a nuclease cum helicase—in cooperation with Cascade surveillance complex cleaves the target DNA. Unlike the Cascade/I-E, which is composed of five subunits, the Cascade/I-C is made of only three subunits lacking the CRISPR RNA processing enzyme Cas6, whose role is assumed by Cas5. How these differences in the composition and organization of Cascade subunits in type I-C influence the Cas3/I-C binding and its target cleavage mechanism is poorly understood. Here, we show that Cas3/I-C is intrinsically a single-strand specific promiscuous nuclease. Apart from the helicase domain, a constellation of highly conserved residues—which are unique to type I-C—located in the uncharacterized C-terminal domain appears to influence the nuclease activity. Recruited by Cascade/I-C, the HD nuclease of Cas3/I-C nicks the single-stranded region of the non-target strand and positions the helicase motor. Powered by ATP, the helicase motor reels in the target DNA, until it encounters the roadblock en route, which stimulates the HD nuclease. Remarkably, we show that Cas3/I-C supplants Cas3/I-E for CRISPR interference in type I-E in vivo, suggesting that the target cleavage mechanism is evolutionarily conserved between type I-C and type I-E despite the architectural difference exhibited by Cascade/I-C and Cascade/I-E.
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Affiliation(s)
- Siddharth Nimkar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - B Anand
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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8
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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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9
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Cas3 Protein-A Review of a Multi-Tasking Machine. Genes (Basel) 2020; 11:genes11020208. [PMID: 32085454 PMCID: PMC7074321 DOI: 10.3390/genes11020208] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 01/20/2023] Open
Abstract
Cas3 has essential functions in CRISPR immunity but its other activities and roles, in vitro and in cells, are less widely known. We offer a concise review of the latest understanding and questions arising from studies of Cas3 mechanism during CRISPR immunity, and highlight recent attempts at using Cas3 for genetic editing. We then spotlight involvement of Cas3 in other aspects of cell biology, for which understanding is lacking—these focus on CRISPR systems as regulators of cellular processes in addition to defense against mobile genetic elements.
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10
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Morgenthaler AB, Kinney WR, Ebmeier CC, Walsh CM, Snyder DJ, Cooper VS, Old WM, Copley SD. Mutations that improve efficiency of a weak-link enzyme are rare compared to adaptive mutations elsewhere in the genome. eLife 2019; 8:53535. [PMID: 31815667 PMCID: PMC6941894 DOI: 10.7554/elife.53535] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 12/02/2019] [Indexed: 11/13/2022] Open
Abstract
New enzymes often evolve by gene amplification and divergence. Previous experimental studies have followed the evolutionary trajectory of an amplified gene, but have not considered mutations elsewhere in the genome when fitness is limited by an evolving gene. We have evolved a strain of Escherichia coli in which a secondary promiscuous activity has been recruited to serve an essential function. The gene encoding the ‘weak-link’ enzyme amplified in all eight populations, but mutations improving the newly needed activity occurred in only one. Most adaptive mutations occurred elsewhere in the genome. Some mutations increase expression of the enzyme upstream of the weak-link enzyme, pushing material through the dysfunctional metabolic pathway. Others enhance production of a co-substrate for a downstream enzyme, thereby pulling material through the pathway. Most of these latter mutations are detrimental in wild-type E. coli, and thus would require reversion or compensation once a sufficient new activity has evolved.
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Affiliation(s)
- Andrew B Morgenthaler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, United States
| | - Wallis R Kinney
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, United States
| | - Christopher C Ebmeier
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Corinne M Walsh
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, United States.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, United States
| | - Daniel J Snyder
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Vaughn S Cooper
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, United States
| | - William M Old
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States
| | - Shelley D Copley
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, United States
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11
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Morisaka H, Yoshimi K, Okuzaki Y, Gee P, Kunihiro Y, Sonpho E, Xu H, Sasakawa N, Naito Y, Nakada S, Yamamoto T, Sano S, Hotta A, Takeda J, Mashimo T. CRISPR-Cas3 induces broad and unidirectional genome editing in human cells. Nat Commun 2019; 10:5302. [PMID: 31811138 PMCID: PMC6897959 DOI: 10.1038/s41467-019-13226-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 10/29/2019] [Indexed: 12/21/2022] Open
Abstract
Although single-component Class 2 CRISPR systems, such as type II Cas9 or type V Cas12a (Cpf1), are widely used for genome editing in eukaryotic cells, the application of multi-component Class 1 CRISPR has been less developed. Here we demonstrate that type I-E CRISPR mediates distinct DNA cleavage activity in human cells. Notably, Cas3, which possesses helicase and nuclease activity, predominantly triggered several thousand base pair deletions upstream of the 5'-ARG protospacer adjacent motif (PAM), without prominent off-target activity. This Cas3-mediated directional and broad DNA degradation can be used to introduce functional gene knockouts and knock-ins. As an example of potential therapeutic applications, we show Cas3-mediated exon-skipping of the Duchenne muscular dystrophy (DMD) gene in patient-induced pluripotent stem cells (iPSCs). These findings broaden our understanding of the Class 1 CRISPR system, which may serve as a unique genome editing tool in eukaryotic cells distinct from the Class 2 CRISPR system.
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Affiliation(s)
- Hiroyuki Morisaka
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Department of Dermatology, Kochi Medical School, Kochi University, Kochi, 783-8505, Japan
| | - Kazuto Yoshimi
- Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Institute of Experimental Animal Sciences, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Division of Animal Genetics, Laboratory Animal Research Center, Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Yuya Okuzaki
- Center for iPS Cell Research and Application (CiRA), Department of Clinical Application, Kyoto University, Kyoto, 606-8507, Japan
| | - Peter Gee
- Center for iPS Cell Research and Application (CiRA), Department of Clinical Application, Kyoto University, Kyoto, 606-8507, Japan
| | - Yayoi Kunihiro
- Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Ekasit Sonpho
- Institute of Experimental Animal Sciences, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Huaigeng Xu
- Center for iPS Cell Research and Application (CiRA), Department of Clinical Application, Kyoto University, Kyoto, 606-8507, Japan
| | - Noriko Sasakawa
- Center for iPS Cell Research and Application (CiRA), Department of Clinical Application, Kyoto University, Kyoto, 606-8507, Japan
| | - Yuki Naito
- Database Center for Life Science, Mishima, 411-8540, Japan
- National Institute of Genetics, Mishima, 411-8540, Japan
| | - Shinichiro Nakada
- Institute for Advanced Co-Creation Studies, Osaka University, Osaka, 565-0871, Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Shigetoshi Sano
- Department of Dermatology, Kochi Medical School, Kochi University, Kochi, 783-8505, Japan
| | - Akitsu Hotta
- Center for iPS Cell Research and Application (CiRA), Department of Clinical Application, Kyoto University, Kyoto, 606-8507, Japan.
| | - Junji Takeda
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
- Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan.
| | - Tomoji Mashimo
- Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
- Institute of Experimental Animal Sciences, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
- Division of Animal Genetics, Laboratory Animal Research Center, Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan.
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12
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Medina-Aparicio L, Dávila S, Rebollar-Flores JE, Calva E, Hernández-Lucas I. The CRISPR-Cas system in Enterobacteriaceae. Pathog Dis 2018; 76:4794941. [PMID: 29325038 DOI: 10.1093/femspd/fty002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/08/2018] [Indexed: 12/20/2022] Open
Abstract
In nature, microorganisms are constantly exposed to multiple viral infections and thus have developed many strategies to survive phage attack and invasion by foreign DNA. One of such strategies is the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) bacterial immunological system. This defense mechanism is widespread in prokaryotes including several families such as Enterobacteriaceae. Much knowledge about the CRISPR-Cas system has been generated, including its biological functions, transcriptional regulation, distribution, utility as a molecular marker and as a tool for specific genome editing. This review focuses on these aspects and describes the state of the art of the CRISPR-Cas system in the Enterobacteriaceae bacterial family.
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Affiliation(s)
- Liliana Medina-Aparicio
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México
| | - Sonia Dávila
- Centro de Investigación en Dinámica Celular, Universidad Autónoma del Estado de Morelos, Av. Universidad No. 1001, Cuernavaca, Morelos 62209, México
| | - Javier E Rebollar-Flores
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México
| | - Edmundo Calva
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México
| | - Ismael Hernández-Lucas
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, México
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13
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Giant viruses as protein-coated amoeban mitochondria? Virus Res 2018; 253:77-86. [DOI: 10.1016/j.virusres.2018.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 01/18/2023]
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14
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Beyond Native Cas9: Manipulating Genomic Information and Function. Trends Biotechnol 2017; 35:983-996. [DOI: 10.1016/j.tibtech.2017.06.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/22/2017] [Accepted: 06/08/2017] [Indexed: 02/07/2023]
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15
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Tiruveedula GSS, Wangikar PP. Gene essentiality, conservation index and co-evolution of genes in cyanobacteria. PLoS One 2017; 12:e0178565. [PMID: 28594867 PMCID: PMC5464585 DOI: 10.1371/journal.pone.0178565] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/15/2017] [Indexed: 11/18/2022] Open
Abstract
Cyanobacteria, a group of photosynthetic prokaryotes, dominate the earth with ~ 1015 g wet biomass. Despite diversity in habitats and an ancient origin, cyanobacterial phylum has retained a significant core genome. Cyanobacteria are being explored for direct conversion of solar energy and carbon dioxide into biofuels. For this, efficient cyanobacterial strains will need to be designed via metabolic engineering. This will require identification of target knockouts to channelize the flow of carbon toward the product of interest while minimizing deletions of essential genes. We propose "Gene Conservation Index" (GCI) as a quick measure to predict gene essentiality in cyanobacteria. GCI is based on phylogenetic profile of a gene constructed with a reduced dataset of cyanobacterial genomes. GCI is the percentage of organism clusters in which the query gene is present in the reduced dataset. Of the 750 genes deemed to be essential in the experimental study on S. elongatus PCC 7942, we found 494 to be conserved across the phylum which largely comprise of the essential metabolic pathways. On the contrary, the conserved but non-essential genes broadly comprise of genes required under stress conditions. Exceptions to this rule include genes such as the glycogen synthesis and degradation enzymes, deoxyribose-phosphate aldolase (DERA), glucose-6-phosphate 1-dehydrogenase (zwf) and fructose-1,6-bisphosphatase class1, which are conserved but non-essential. While the essential genes are to be avoided during gene knockout studies as potentially lethal deletions, the non-essential but conserved set of genes could be interesting targets for metabolic engineering. Further, we identify clusters of co-evolving genes (CCG), which provide insights that may be useful in annotation. Principal component analysis (PCA) plots of the CCGs are demonstrated as data visualization tools that are complementary to the conventional heatmaps. Our dataset consists of phylogenetic profiles for 23,643 non-redundant cyanobacterial genes. We believe that the data and the analysis presented here will be a great resource to the scientific community interested in cyanobacteria.
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Affiliation(s)
- Gopi Siva Sai Tiruveedula
- Department of Chemical Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore, India
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Pramod P. Wangikar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
- DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai, India
- Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
- * E-mail:
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16
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Easy regulation of metabolic flux in Escherichia coli using an endogenous type I-E CRISPR-Cas system. Microb Cell Fact 2016; 15:195. [PMID: 27842593 PMCID: PMC5109708 DOI: 10.1186/s12934-016-0594-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/06/2016] [Indexed: 12/26/2022] Open
Abstract
Background Clustered regularly interspaced short palindromic repeats interference (CRISPRi) is a recently developed powerful tool for gene regulation. In Escherichia coli, the type I CRISPR system expressed endogenously shall be easy for internal regulation without causing metabolic burden in compared with the widely used type II system, which expressed dCas9 as an additional plasmid. Results By knocking out cas3 and activating the expression of CRISPR-associated complex for antiviral defense (Cascade), we constructed a native CRISPRi system in E. coli. Downregulation of the target gene from 6 to 82% was demonstrated using green fluorescent protein. Regulation of the citrate synthase gene (gltA) in the TCA cycle affected host metabolism. The effect of metabolic flux regulation was demonstrated by the poly-3-hydroxbutyrate (PHB) accumulation in vivo. Conclusion By regulating native gltA in E. coli using an engineered endogenous type I-E CRISPR system, we redirected metabolic flux from the central metabolic pathway to the PHB synthesis pathway. This study demonstrated that the endogenous type I-E CRISPR-Cas system is an easy and effective method for regulating internal metabolic pathways, which is useful for product synthesis. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0594-4) contains supplementary material, which is available to authorized users.
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17
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Abstract
Hybridization of RNA to its template DNA strand during transcription induces formation of R-loops-RNA:DNA hybrids with unpaired non-template DNA strands. Although unresolved R-loops can be detrimental, some R-loops contribute to regulation of chromatin structure. Consequently, R-loops help regulate gene expression and play important roles in numerous cellular processes.
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Affiliation(s)
- Thomas G Fazzio
- a Department of Molecular, Cell, and Cancer Biology , University of Massachusetts Medical School , Worcester , MA , USA.,b Program in Molecular Medicine , University of Massachusetts Medical School , Worcester , MA , USA
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18
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Elmore J, Deighan T, Westpheling J, Terns RM, Terns MP. DNA targeting by the type I-G and type I-A CRISPR-Cas systems of Pyrococcus furiosus. Nucleic Acids Res 2015; 43:10353-63. [PMID: 26519471 PMCID: PMC4666368 DOI: 10.1093/nar/gkv1140] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/16/2015] [Indexed: 12/26/2022] Open
Abstract
CRISPR–Cas systems silence plasmids and viruses in prokaryotes. CRISPR–Cas effector complexes contain CRISPR RNAs (crRNAs) that include sequences captured from invaders and direct CRISPR-associated (Cas) proteins to destroy corresponding invader nucleic acids. Pyrococcus furiosus (Pfu) harbors three CRISPR–Cas immune systems: a Cst (Type I-G) system with an associated Cmr (Type III-B) module at one locus, and a partial Csa (Type I-A) module (lacking known invader sequence acquisition and crRNA processing genes) at another locus. The Pfu Cmr complex cleaves complementary target RNAs, and Csa systems have been shown to target DNA, while the mechanism by which Cst complexes silence invaders is unknown. In this study, we investigated the function of the Cst as well as Csa system in Pfu strains harboring a single CRISPR–Cas system. Plasmid transformation assays revealed that the Cst and Csa systems both function by DNA silencing and utilize similar flanking sequence information (PAMs) to identify invader DNA. Silencing by each system specifically requires its associated Cas3 nuclease. crRNAs from the 7 shared CRISPR loci in Pfu are processed for use by all 3 effector complexes, and Northern analysis revealed that individual effector complexes dictate the profile of mature crRNA species that is generated.
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Affiliation(s)
- Joshua Elmore
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Trace Deighan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Jan Westpheling
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Rebecca M Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Michael P Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA Department of Genetics, University of Georgia, Athens, GA 30602, USA Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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19
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Guo Y, Kragelund BB, White MF, Peng X. Functional Characterization of a Conserved Archaeal Viral Operon Revealing Single-Stranded DNA Binding, Annealing and Nuclease Activities. J Mol Biol 2015; 427:2179-91. [DOI: 10.1016/j.jmb.2015.03.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 11/15/2022]
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20
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Charpentier E, Richter H, van der Oost J, White MF. Biogenesis pathways of RNA guides in archaeal and bacterial CRISPR-Cas adaptive immunity. FEMS Microbiol Rev 2015; 39:428-41. [PMID: 25994611 PMCID: PMC5965381 DOI: 10.1093/femsre/fuv023] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2015] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas is an RNA-mediated adaptive immune system that defends bacteria and archaea against mobile genetic elements. Short mature CRISPR RNAs (crRNAs) are key elements in the interference step of the immune pathway. A CRISPR array composed of a series of repeats interspaced by spacer sequences acquired from invading mobile genomes is transcribed as a precursor crRNA (pre-crRNA) molecule. This pre-crRNA undergoes one or two maturation steps to generate the mature crRNAs that guide CRISPR-associated (Cas) protein(s) to cognate invading genomes for their destruction. Different types of CRISPR-Cas systems have evolved distinct crRNA biogenesis pathways that implicate highly sophisticated processing mechanisms. In Types I and III CRISPR-Cas systems, a specific endoribonuclease of the Cas6 family, either standalone or in a complex with other Cas proteins, cleaves the pre-crRNA within the repeat regions. In Type II systems, the trans-acting small RNA (tracrRNA) base pairs with each repeat of the pre-crRNA to form a dual-RNA that is cleaved by the housekeeping RNase III in the presence of the protein Cas9. In this review, we present a detailed comparative analysis of pre-crRNA recognition and cleavage mechanisms involved in the biogenesis of guide crRNAs in the three CRISPR-Cas types. This review presents a detailed comparative analysis of pre-crRNA recognition and cleavage mechanisms involved in the biogenesis of guide crRNAs in the different bacterial and archaeal CRISPR-Cas immune systems.
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Affiliation(s)
- Emmanuelle Charpentier
- Helmholtz Centre for Infection Research, Department of Regulation in Infection Biology, Braunschweig 38124, Germany The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå 90187, Sweden Hannover Medical School, Hannover 30625, Germany
| | - Hagen Richter
- Helmholtz Centre for Infection Research, Department of Regulation in Infection Biology, Braunschweig 38124, Germany
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Wageningen 6703 HB, the Netherlands
| | - Malcolm F White
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, UK
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21
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Minias AE, Brzostek AM, Korycka- Machala M, Dziadek B, Minias P, Rajagopalan M, Madiraju M, Dziadek J. RNase HI Is Essential for Survival of Mycobacterium smegmatis. PLoS One 2015; 10:e0126260. [PMID: 25965344 PMCID: PMC4429107 DOI: 10.1371/journal.pone.0126260] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/31/2015] [Indexed: 12/21/2022] Open
Abstract
RNases H are involved in the removal of RNA from RNA/DNA hybrids. Type I RNases H are thought to recognize and cleave the RNA/DNA duplex when at least four ribonucleotides are present. Here we investigated the importance of RNase H type I encoding genes for model organism Mycobacterium smegmatis. By performing gene replacement through homologous recombination, we demonstrate that each of the two presumable RNase H type I encoding genes, rnhA and MSMEG4305, can be removed from M. smegmatis genome without affecting the growth rate of the mutant. Further, we demonstrate that deletion of both RNases H type I encoding genes in M. smegmatis leads to synthetic lethality. Finally, we question the possibility of existence of RNase HI related alternative mode of initiation of DNA replication in M. smegmatis, the process initially discovered in Escherichia coli. We suspect that synthetic lethality of double mutant lacking RNases H type I is caused by formation of R-loops leading to collapse of replication forks. We report Mycobacterium smegmatis as the first bacterial species, where function of RNase H type I has been found essential.
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Affiliation(s)
- Alina E. Minias
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
- * E-mail: (AM); (JD)
| | - Anna M. Brzostek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | | | - Bozena Dziadek
- Department of Immunoparasitology, University of Lodz, Lodz, Poland
| | - Piotr Minias
- Department of Teacher Training and Biodiversity Studies, University of Lodz, Lodz, Poland
| | - Malini Rajagopalan
- Department of Microbiology, University of Texas Health Center at Tyler, Tyler, Texas, United States of America
| | - Murty Madiraju
- Department of Microbiology, University of Texas Health Center at Tyler, Tyler, Texas, United States of America
| | - Jaroslaw Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
- * E-mail: (AM); (JD)
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22
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Molecular insights into DNA interference by CRISPR-associated nuclease-helicase Cas3. Proc Natl Acad Sci U S A 2014; 111:16359-64. [PMID: 25368186 DOI: 10.1073/pnas.1410806111] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mobile genetic elements in bacteria are neutralized by a system based on clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins. Type I CRISPR-Cas systems use a "Cascade" ribonucleoprotein complex to guide RNA specifically to complementary sequence in invader double-stranded DNA (dsDNA), a process called "interference." After target recognition by Cascade, formation of an R-loop triggers recruitment of a Cas3 nuclease-helicase, completing the interference process by destroying the invader dsDNA. To elucidate the molecular mechanism of CRISPR interference, we analyzed crystal structures of Cas3 from the bacterium Thermobaculum terrenum, with and without a bound ATP analog. The structures reveal a histidine-aspartate (HD)-type nuclease domain fused to superfamily-2 (SF2) helicase domains and a distinct C-terminal domain. Binding of ATP analog at the interface of the SF2 helicase RecA-like domains rearranges a motif V with implications for the enzyme mechanism. The HD-nucleolytic site contains two metal ions that are positioned at the end of a proposed nucleic acid-binding tunnel running through the SF2 helicase structure. This structural alignment suggests a mechanism for 3' to 5' nucleolytic processing of the displaced strand of invader DNA that is coordinated with ATP-dependent 3' to 5' translocation of Cas3 along DNA. In agreement with biochemical studies, the presented Cas3 structures reveal important mechanistic details on the neutralization of genetic invaders by type I CRISPR-Cas systems.
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23
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Yang CD, Chen YH, Huang HY, Huang HD, Tseng CP. CRP represses the CRISPR/Cas system in Escherichia coli: evidence that endogenous CRISPR spacers impede phage P1 replication. Mol Microbiol 2014; 92:1072-91. [PMID: 24720807 DOI: 10.1111/mmi.12614] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2014] [Indexed: 12/26/2022]
Abstract
The CRISPR/Cas system is an important aspect in bacterial immunology. The anti-phage activity of the CRISPR system has been established using synthetic CRISPR spacers, but in vivo studies of endogenous CRISPR spacers are relatively scarce. Here, we showed that bacteriophage P1 titre in Escherichia coli decreased in the glucose-containing medium compared with that in the absence of glucose. This glucose effect of E. coli against phage P1 infection disappeared in cse3 deletion mutants. The effect on the susceptibility to phage P1 was associated with cAMP receptor protein (CRP)-mediated repression of cas genes transcription and crRNA maturation. Analysis of the regulatory element in the cse1 promoter region revealed a novel CRP binding site, which overlapped with a LeuO binding site. Furthermore, the limited sequence identity between endogenous spacers and the phage P1 genome was necessary and sufficient for CRISPR-mediated repression of phage P1 replication. Trans-expression of the third and seventh spacers in the CRISPR I region or third and sixth spacers in the CRISPR II region effectively reduced phage P1 titres in the CRISPR deletion mutants. These results demonstrate a novel regulatory mechanism for cas repression by CRP and provide evidence that endogenous spacers can repress phage P1 replication in E. coli.
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Affiliation(s)
- Chi-Dung Yang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, 300, Taiwan
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24
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Molecular mechanisms of CRISPR-mediated microbial immunity. Cell Mol Life Sci 2014; 71:449-65. [PMID: 23959171 PMCID: PMC3890593 DOI: 10.1007/s00018-013-1438-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/21/2013] [Accepted: 07/24/2013] [Indexed: 12/15/2022]
Abstract
Bacteriophages (phages) infect bacteria in order to replicate and burst out of the host, killing the cell, when reproduction is completed. Thus, from a bacterial perspective, phages pose a persistent lethal threat to bacterial populations. Not surprisingly, bacteria evolved multiple defense barriers to interfere with nearly every step of phage life cycles. Phages respond to this selection pressure by counter-evolving their genomes to evade bacterial resistance. The antagonistic interaction between bacteria and rapidly diversifying viruses promotes the evolution and dissemination of bacteriophage-resistance mechanisms in bacteria. Recently, an adaptive microbial immune system, named clustered regularly interspaced short palindromic repeats (CRISPR) and which provides acquired immunity against viruses and plasmids, has been identified. Unlike the restriction–modification anti-phage barrier that subjects to cleavage any foreign DNA lacking a protective methyl-tag in the target site, the CRISPR–Cas systems are invader-specific, adaptive, and heritable. In this review, we focus on the molecular mechanisms of interference/immunity provided by different CRISPR–Cas systems.
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25
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Ramia NF, Tang L, Cocozaki AI, Li H. Staphylococcus epidermidis Csm1 is a 3'-5' exonuclease. Nucleic Acids Res 2013; 42:1129-38. [PMID: 24121684 PMCID: PMC3902914 DOI: 10.1093/nar/gkt914] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) offer an adaptive immune system that protects bacteria and archaea from nucleic acid invaders through an RNA-mediated nucleic acid cleavage mechanism. Our knowledge of nucleic acid cleavage mechanisms is limited to three examples of widely different ribonucleoprotein particles that target either DNA or RNA. Staphylococcus epidermidis belongs to the Type III-A CRISPR system and has been shown to interfere with invading DNA in vivo. The Type III-A CRISPR system is characterized by the presence of Csm1, a member of Cas10 family of proteins, that has a permuted histidine–aspartate domain and a nucleotidyl cyclase-like domain, both of which contain sequence features characteristic of nucleases. In this work, we show in vitro that a recombinant S. epidermidis Csm1 cleaves single-stranded DNA and RNA exonucleolytically in the 3′–5′ direction. We further showed that both cleavage activities are divalent-metal-dependent and reside in the GGDD motif of the cyclase-like domain. Our data suggest that Csm1 may work in the context of an effector complex to degrade invading DNA and participate in CRISPR RNA maturation.
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Affiliation(s)
- Nancy F Ramia
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA and Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
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26
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Abstract
CRISPR (cluster of regularly interspaced palindromic repeats) is a prokaryotic adaptive defence system, providing immunity against mobile genetic elements such as viruses. Genomically encoded crRNA (CRISPR RNA) is used by Cas (CRISPR-associated) proteins to target and subsequently degrade nucleic acids of invading entities in a sequence-dependent manner. The process is known as ‘interference’. In the present review we cover recent progress on the structural biology of the CRISPR/Cas system, focusing on the Cas proteins and complexes that catalyse crRNA biogenesis and interference. Structural studies have helped in the elucidation of key mechanisms, including the recognition and cleavage of crRNA by the Cas6 and Cas5 proteins, where remarkable diversity at the level of both substrate recognition and catalysis has become apparent. The RNA-binding RAMP (repeat-associated mysterious protein) domain is present in the Cas5, Cas6, Cas7 and Cmr3 protein families and RAMP-like domains are found in Cas2 and Cas10. Structural analysis has also revealed an evolutionary link between the small subunits of the type I and type III-B interference complexes. Future studies of the interference complexes and their constituent components will transform our understanding of the system.
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27
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Mulepati S, Bailey S. In vitro reconstitution of an Escherichia coli RNA-guided immune system reveals unidirectional, ATP-dependent degradation of DNA target. J Biol Chem 2013; 288:22184-92. [PMID: 23760266 DOI: 10.1074/jbc.m113.472233] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many prokaryotes utilize small RNA transcribed from clustered, regularly interspaced, short palindromic repeats (CRISPRs) to protect themselves from foreign genetic elements, such as phage and plasmids. In Escherichia coli, this small RNA is packaged into a surveillance complex (Cascade) that uses the RNA sequence to direct binding to invasive DNA. Once bound, Cascade recruits the Cas3 nuclease-helicase, which then proceeds to progressively degrade the invading DNA. Here, using individually purified Cascade and Cas3 from E. coli, we reconstitute CRISPR-mediated plasmid degradation in vitro. Analysis of this reconstituted assay suggests that Cascade recruits Cas3 to a single-stranded region of the DNA target exposed by Cascade binding. Cas3 then nicks the exposed DNA. Recruitment and nicking is stimulated by the presence, but not hydrolysis, of ATP. Following nicking and powered by ATP hydrolysis, the concerted actions of the helicase and nuclease domains of Cas3 proceed to unwind and degrade the entire DNA target in a unidirectional manner.
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Affiliation(s)
- Sabin Mulepati
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
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28
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Ivančić-Baće I, Radovčić M, Bočkor L, Howard JL, Bolt EL. Cas3 stimulates runaway replication of a ColE1 plasmid in Escherichia coli and antagonises RNaseHI. RNA Biol 2013; 10:770-8. [PMID: 23406879 PMCID: PMC3737335 DOI: 10.4161/rna.23876] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/31/2013] [Accepted: 02/04/2013] [Indexed: 12/25/2022] Open
Abstract
Cas3 nuclease-helicase is part of CRISPR immunity systems in many bacteria and archaea. In type I CRISPR, Cas3 nuclease degrades invader DNA that has been base-paired to crRNA as an R-loop within a "Cascade" complex. An R-loop is a DNA-RNA hybrid that includes a displaced single-strand DNA loop. Purified Cas3 from E. coli and the archaeon M. thermautrophicus can process R-loops without DNA/RNA sequence specificity and without Cascade. This has potential to affect other aspects of microbial biology that involve R-loops. Regulatory RNAs and host cell proteins modulate replication of ColE1 plasmids (e.g., pUC) from R-loop primers. We observed that Cas3 could override endogenous control of a ColE1 replicon, stimulating uncontrolled ("runaway") replication and resulting in much higher plasmid yields. This effect was absent when using helicase-defective Cas3 (Cas3 (K320L) ) or a non-ColE1 plasmid, and was dependent on RNaseHI. Cas3 also promoted formation of plasmid multimers or concatemers, a phenotype consistent with deregulated ColE1 replication and typical of cells lacking RNaseHI. These effects of Cas3 on ColE1 plasmids are inconsistent with it unwinding R-loops in vivo, at least in this assay. We discuss a model of how Cas3 might be able to regulate RNA molecules in vivo, unless it is targeted to CRISPR defense by Cascade, or kept in check by RecG and RNaseHI.
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Affiliation(s)
- Ivana Ivančić-Baće
- Faculty of Science; Department of Molecular Biology; University of Zagreb; Zagreb, Croatia
| | - Marin Radovčić
- Faculty of Science; Department of Molecular Biology; University of Zagreb; Zagreb, Croatia
| | - Luka Bočkor
- Faculty of Science; Department of Molecular Biology; University of Zagreb; Zagreb, Croatia
| | | | - Edward L. Bolt
- School of Biomedical Sciences, University of Nottingham, Nottingham UK
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29
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Nickel L, Weidenbach K, Jäger D, Backofen R, Lange SJ, Heidrich N, Schmitz RA. Two CRISPR-Cas systems in Methanosarcina mazei strain Gö1 display common processing features despite belonging to different types I and III. RNA Biol 2013; 10:779-91. [PMID: 23619576 DOI: 10.4161/rna.23928] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) system represents a highly adaptive and heritable defense system against foreign nucleic acids in bacteria and archaea. We analyzed the two CRISPR-Cas systems in Methanosarcina mazei strain Gö1. Although belonging to different subtypes (I-B and III-B), the leaders and repeats of both loci are nearly identical. Also, despite many point mutations in each array, a common hairpin motif was identified in the repeats by a bioinformatics analysis and in vitro structural probing. The expression and maturation of CRISPR-derived RNAs (crRNAs) were studied in vitro and in vivo. Both respective potential Cas6b-type endonucleases were purified and their activity tested in vitro. Each protein showed significant activity and could cleave both repeats at the same processing site. Cas6b of subtype III-B, however, was significantly more efficient in its cleavage activity compared with Cas6b of subtype I-B. Northern blot and differential RNAseq analyses were performed to investigate in vivo transcription and maturation of crRNAs, revealing generally very low expression of both systems, whereas significant induction at high NaCl concentrations was observed. crRNAs derived proximal to the leader were generally more abundant than distal ones and in vivo processing sites were clarified for both loci, confirming the previously well-established 8 nt 5' repeat tags. The 3'-ends were more diverse, but generally ended in a prefix of the following repeat sequence (3'-tag). The analysis further revealed a 5'-hydroxy and 3'-phosphate termini architecture of small crRNAs specific for cleavage products of Cas6 endonucleases from type I-E and I-F and type III-B.
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Affiliation(s)
- Lisa Nickel
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, Germany
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Chylinski K, Le Rhun A, Charpentier E. The tracrRNA and Cas9 families of type II CRISPR-Cas immunity systems. RNA Biol 2013; 10:726-37. [PMID: 23563642 PMCID: PMC3737331 DOI: 10.4161/rna.24321] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
CRISPR-Cas is a rapidly evolving RNA-mediated adaptive immune system that protects bacteria and archaea against mobile genetic elements. The system relies on the activity of short mature CRISPR RNAs (crRNAs) that guide Cas protein(s) to silence invading nucleic acids. A set of CRISPR-Cas, type II, requires a trans-activating small RNA, tracrRNA, for maturation of precursor crRNA (pre-crRNA) and interference with invading sequences. Following co-processing of tracrRNA and pre-crRNA by RNase III, dual-tracrRNA:crRNA guides the CRISPR-associated endonuclease Cas9 (Csn1) to cleave site-specifically cognate target DNA. Here, we screened available genomes for type II CRISPR-Cas loci by searching for Cas9 orthologs. We analyzed 75 representative loci, and for 56 of them we predicted novel tracrRNA orthologs. Our analysis demonstrates a high diversity in cas operon architecture and position of the tracrRNA gene within CRISPR-Cas loci. We observed a correlation between locus heterogeneity and Cas9 sequence diversity, resulting in the identification of various type II CRISPR-Cas subgroups. We validated the expression and co-processing of predicted tracrRNAs and pre-crRNAs by RNA sequencing in five bacterial species. This study reveals tracrRNA family as an atypical, small RNA family with no obvious conservation of structure, sequence or localization within type II CRISPR-Cas loci. The tracrRNA family is however characterized by the conserved feature to base-pair to cognate pre-crRNA repeats, an essential function for crRNA maturation and DNA silencing by dual-RNA:Cas9. The large panel of tracrRNA and Cas9 ortholog sequences should constitute a useful database to improve the design of RNA-programmable Cas9 as genome editing tool.
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Affiliation(s)
- Krzysztof Chylinski
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
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Barrangou R. CRISPR-Cas systems and RNA-guided interference. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:267-78. [DOI: 10.1002/wrna.1159] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Dieterich C, Stadler PF. Computational biology of RNA interactions. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:107-20. [PMID: 23139167 DOI: 10.1002/wrna.1147] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The biodiversity of the RNA world has been underestimated for decades. RNA molecules are key building blocks, sensors, and regulators of modern cells. The biological function of RNA molecules cannot be separated from their ability to bind to and interact with a wide space of chemical species, including small molecules, nucleic acids, and proteins. Computational chemists, physicists, and biologists have developed a rich tool set for modeling and predicting RNA interactions. These interactions are to some extent determined by the binding conformation of the RNA molecule. RNA binding conformations are approximated with often acceptable accuracy by sequence and secondary structure motifs. Secondary structure ensembles of a given RNA molecule can be efficiently computed in many relevant situations by employing a standard energy model for base pair interactions and dynamic programming techniques. The case of bi-molecular RNA-RNA interactions can be seen as an extension of this approach. However, unbiased transcriptome-wide scans for local RNA-RNA interactions are computationally challenging yet become efficient if the binding motif/mode is known and other external information can be used to confine the search space. Computational methods are less developed for proteins and small molecules, which bind to RNA with very high specificity. Binding descriptors of proteins are usually determined by in vitro high-throughput assays (e.g., microarrays or sequencing). Intriguingly, recent experimental advances, which are mostly based on light-induced cross-linking of binding partners, render in vivo binding patterns accessible yet require new computational methods for careful data interpretation. The grand challenge is to model the in vivo situation where a complex interplay of RNA binders competes for the same target RNA molecule. Evidently, bioinformaticians are just catching up with the impressive pace of these developments.
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Affiliation(s)
- Christoph Dieterich
- Berlin Institute for Medical Systems Biology, Max Delbrück Centre for Molecular Medicine, Robert-Rössle-Straße 10, Berlin, Germany.
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Fineran PC, Charpentier E. Memory of viral infections by CRISPR-Cas adaptive immune systems: acquisition of new information. Virology 2012; 434:202-9. [PMID: 23123013 DOI: 10.1016/j.virol.2012.10.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 02/08/2023]
Abstract
Multiple organisms face the threat of viral infections. To combat phage invasion, bacteria and archaea have evolved an adaptive mechanism of protection against exogenic mobile genetic elements, called CRISPR-Cas. In this defense strategy, phage infection is memorized via acquisition of a short invader sequence, called a spacer, into the CRISPR locus of the host genome. Upon repeated infection, the 'vaccinated' host expresses the spacer as a precursor RNA, which is processed into a mature CRISPR RNA (crRNA) that guides an endonuclease to the matching invader for its ultimate destruction. Recent efforts have uncovered molecular details underlying the crRNA biogenesis and interference steps. However, until recently the step of adaptation had remained largely uninvestigated. In this minireview, we focus on recent publications that have begun to reveal molecular insights into the adaptive step of CRISPR-Cas immunity, which is required for the development of the heritable memory of the host against viruses.
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Affiliation(s)
- Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
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Function and regulation of clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR associated (Cas) systems. Viruses 2012. [PMID: 23202464 PMCID: PMC3497052 DOI: 10.3390/v4102291] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Phages are the most abundant biological entities on earth and pose a constant challenge to their bacterial hosts. Thus, bacteria have evolved numerous 'innate' mechanisms of defense against phage, such as abortive infection or restriction/modification systems. In contrast, the clustered regularly interspaced short palindromic repeats (CRISPR) systems provide acquired, yet heritable, sequence-specific 'adaptive' immunity against phage and other horizontally-acquired elements, such as plasmids. Resistance is acquired following viral infection or plasmid uptake when a short sequence of the foreign genome is added to the CRISPR array. CRISPRs are then transcribed and processed, generally by CRISPR associated (Cas) proteins, into short interfering RNAs (crRNAs), which form part of a ribonucleoprotein complex. This complex guides the crRNA to the complementary invading nucleic acid and targets this for degradation. Recently, there have been rapid advances in our understanding of CRISPR/Cas systems. In this review, we will present the current model(s) of the molecular events involved in both the acquisition of immunity and interference stages and will also address recent progress in our knowledge of the regulation of CRISPR/Cas systems.
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Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E. A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity. SCIENCE (NEW YORK, N.Y.) 2012. [PMID: 22745249 DOI: 10.1126/science.1225829.] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide bacteria and archaea with adaptive immunity against viruses and plasmids by using CRISPR RNAs (crRNAs) to guide the silencing of invading nucleic acids. We show here that in a subset of these systems, the mature crRNA that is base-paired to trans-activating crRNA (tracrRNA) forms a two-RNA structure that directs the CRISPR-associated protein Cas9 to introduce double-stranded (ds) breaks in target DNA. At sites complementary to the crRNA-guide sequence, the Cas9 HNH nuclease domain cleaves the complementary strand, whereas the Cas9 RuvC-like domain cleaves the noncomplementary strand. The dual-tracrRNA:crRNA, when engineered as a single RNA chimera, also directs sequence-specific Cas9 dsDNA cleavage. Our study reveals a family of endonucleases that use dual-RNAs for site-specific DNA cleavage and highlights the potential to exploit the system for RNA-programmable genome editing.
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Affiliation(s)
- Martin Jinek
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
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Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E. A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity. Science 2012; 337:816-21. [PMID: 22745249 PMCID: PMC6286148 DOI: 10.1126/science.1225829] [Citation(s) in RCA: 10083] [Impact Index Per Article: 840.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide bacteria and archaea with adaptive immunity against viruses and plasmids by using CRISPR RNAs (crRNAs) to guide the silencing of invading nucleic acids. We show here that in a subset of these systems, the mature crRNA that is base-paired to trans-activating crRNA (tracrRNA) forms a two-RNA structure that directs the CRISPR-associated protein Cas9 to introduce double-stranded (ds) breaks in target DNA. At sites complementary to the crRNA-guide sequence, the Cas9 HNH nuclease domain cleaves the complementary strand, whereas the Cas9 RuvC-like domain cleaves the noncomplementary strand. The dual-tracrRNA:crRNA, when engineered as a single RNA chimera, also directs sequence-specific Cas9 dsDNA cleavage. Our study reveals a family of endonucleases that use dual-RNAs for site-specific DNA cleavage and highlights the potential to exploit the system for RNA-programmable genome editing.
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Affiliation(s)
- Martin Jinek
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Krzysztof Chylinski
- Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, S-90187 Umeå, Sweden
| | - Ines Fonfara
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, S-90187 Umeå, Sweden
| | - Michael Hauer
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
- Present address: Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Jennifer A. Doudna
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Emmanuelle Charpentier
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, S-90187 Umeå, Sweden
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Richter H, Zoephel J, Schermuly J, Maticzka D, Backofen R, Randau L. Characterization of CRISPR RNA processing in Clostridium thermocellum and Methanococcus maripaludis. Nucleic Acids Res 2012; 40:9887-96. [PMID: 22879377 PMCID: PMC3479195 DOI: 10.1093/nar/gks737] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The CRISPR arrays found in many bacteria and most archaea are transcribed into a long precursor RNA that is processed into small clustered regularly interspaced short palindromic repeats (CRISPR) RNAs (crRNAs). These RNA molecules can contain fragments of viral genomes and mediate, together with a set of CRISPR-associated (Cas) proteins, the prokaryotic immunity against viral attacks. CRISPR/Cas systems are diverse and the Cas6 enzymes that process crRNAs vary between different subtypes. We analysed CRISPR/Cas subtype I-B and present the identification of novel Cas6 enzymes from the bacterial and archaeal model organisms Clostridium thermocellum and Methanococcus maripaludis C5. Methanococcus maripaludis Cas6b in vitro activity and specificity was determined. Two complementary catalytic histidine residues were identified. RNA-Seq analyses revealed in vivo crRNA processing sites, crRNA abundance and orientation of CRISPR transcription within these two organisms. Individual spacer sequences were identified with strong effects on transcription and processing patterns of a CRISPR cluster. These effects will need to be considered for the application of CRISPR clusters that are designed to produce synthetic crRNAs.
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Affiliation(s)
- Hagen Richter
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, D-35037 Marburg, Germany
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Abstract
MOTIVATION While there are numerous programs that can predict RNA or DNA secondary structures, a program that predicts RNA/DNA hetero-dimers is still missing. The lack of easy to use tools for predicting their structure may be in part responsible for the small number of reports of biologically relevant RNA/DNA hetero-dimers. RESULTS We present here an extension to the widely used ViennaRNA Package (Lorenz et al., 2011) for the prediction of the structure of RNA/DNA hetero-dimers. AVAILABILITY http://www.tbi.univie.ac.at/~ronny/RNA/vrna2.html CONTACT ronny@tbi.univie.ac.at, berni@bioinf.uni-leipzig.de SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Ronny Lorenz
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.
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Unwinding and rewinding: double faces of helicase? J Nucleic Acids 2012; 2012:140601. [PMID: 22888405 PMCID: PMC3409536 DOI: 10.1155/2012/140601] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 05/28/2012] [Indexed: 12/29/2022] Open
Abstract
Helicases are enzymes that use ATP-driven motor force to unwind double-stranded DNA or RNA. Recently, increasing evidence demonstrates that some helicases also possess rewinding activity—in other words, they can anneal two complementary single-stranded nucleic acids. All five members of the human RecQ helicase family, helicase PIF1, mitochondrial helicase TWINKLE, and helicase/nuclease Dna2 have been shown to possess strand-annealing activity. Moreover, two recently identified helicases—HARP and AH2 have only ATP-dependent rewinding activity. These findings not only enhance our understanding of helicase enzymes but also establish the presence of a new type of protein: annealing helicases. This paper discusses what is known about these helicases, focusing on their biochemical activity to zip and unzip double-stranded DNA and/or RNA, their possible regulation mechanisms, and biological functions.
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40
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R loops: from transcription byproducts to threats to genome stability. Mol Cell 2012; 46:115-24. [PMID: 22541554 DOI: 10.1016/j.molcel.2012.04.009] [Citation(s) in RCA: 719] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/03/2012] [Accepted: 04/06/2012] [Indexed: 12/17/2022]
Abstract
RNA:DNA hybrid structures known as R loops were thought to be rare byproducts of transcription. In the last decade, however, accumulating evidence has pointed to a new view in which R loops form more frequently, impacting transcription and threatening genome integrity as a source of chromosome fragility and a potential cause of disease. Not surprisingly, cells have evolved mechanisms to prevent cotranscriptional R loop formation. Here we discuss the factors and cellular processes that control R loop formation and the mechanisms by which R loops may influence gene expression and the integrity of the genome.
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41
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Cocozaki AI, Ramia NF, Shao Y, Hale CR, Terns RM, Terns MP, Li H. Structure of the Cmr2 subunit of the CRISPR-Cas RNA silencing complex. Structure 2012; 20:545-53. [PMID: 22405013 DOI: 10.1016/j.str.2012.01.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/10/2012] [Accepted: 01/15/2012] [Indexed: 12/26/2022]
Abstract
Cmr2 is the largest and an essential subunit of a CRISPR RNA-Cas protein complex (the Cmr complex) that cleaves foreign RNA to protect prokaryotes from invading genetic elements. Cmr2 is thought to be the catalytic subunit of the effector complex because of its N-terminal HD nuclease domain. Here, however, we report that the HD domain of Cmr2 is not required for cleavage by the complex in vitro. The 2.3Å crystal structure of Pyrococcus furiosus Cmr2 (lacking the HD domain) reveals two adenylyl cyclase-like and two α-helical domains. The adenylyl cyclase-like domains are arranged as in homodimeric adenylyl cyclases and bind ADP and divalent metals. However, mutagenesis studies show that the metal- and ADP-coordinating residues of Cmr2 are also not critical for cleavage by the complex. Our findings suggest that another component provides the catalytic function and that the essential role by Cmr2 does not require the identified ADP- or metal-binding or HD domains in vitro.
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Affiliation(s)
- Alexis I Cocozaki
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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42
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Ivančić-Baće I, Al Howard J, Bolt EL. Tuning in to interference: R-loops and cascade complexes in CRISPR immunity. J Mol Biol 2012; 422:607-616. [PMID: 22743103 DOI: 10.1016/j.jmb.2012.06.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 06/13/2012] [Accepted: 06/16/2012] [Indexed: 12/26/2022]
Abstract
Stable RNA-DNA hybrids formed by invasion of an RNA strand into duplex DNA, termed R-loops, are notorious for provoking genome instability especially when they arise during transcription. However, in some instances (DNA replication and class switch recombination), R-loops are useful so long as their existence is carefully managed to avoid them persisting. A recent flow of research papers establishes a newly discovered use for R-loops as key intermediates in a prokaryotic immune system called CRISPR (Clustered Regularly Interspersed Short Palindromic Repeats). Structures and mechanism of ribonucleoprotein complexes ("Cascades") that form CRISPR R-loops highlight precision targeting of duplex DNA that has sequence characteristics marking it as foe, enabling nucleolytic destruction of DNA and recycling the Cascade. We review these significant recent breakthroughs in understanding targeting/interference stages of CRISPR immunity and discuss questions arising, including a possible link between targeting and adaptive immunity in prokaryotes.
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Affiliation(s)
- Ivana Ivančić-Baće
- Department of Molecular Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Jamieson Al Howard
- School of Biomedical Sciences, University of Nottingham Medical School, Queens Medical Centre, Nottingham NG7 2UH, UK
| | - Edward L Bolt
- School of Biomedical Sciences, University of Nottingham Medical School, Queens Medical Centre, Nottingham NG7 2UH, UK.
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43
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Swarts DC, Mosterd C, van Passel MWJ, Brouns SJJ. CRISPR interference directs strand specific spacer acquisition. PLoS One 2012; 7:e35888. [PMID: 22558257 PMCID: PMC3338789 DOI: 10.1371/journal.pone.0035888] [Citation(s) in RCA: 277] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 03/28/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND CRISPR/Cas is a widespread adaptive immune system in prokaryotes. This system integrates short stretches of DNA derived from invading nucleic acids into genomic CRISPR loci, which function as memory of previously encountered invaders. In Escherichia coli, transcripts of these loci are cleaved into small RNAs and utilized by the Cascade complex to bind invader DNA, which is then likely degraded by Cas3 during CRISPR interference. RESULTS We describe how a CRISPR-activated E. coli K12 is cured from a high copy number plasmid under non-selective conditions in a CRISPR-mediated way. Cured clones integrated at least one up to five anti-plasmid spacers in genomic CRISPR loci. New spacers are integrated directly downstream of the leader sequence. The spacers are non-randomly selected to target protospacers with an AAG protospacer adjacent motif, which is located directly upstream of the protospacer. A co-occurrence of PAM deviations and CRISPR repeat mutations was observed, indicating that one nucleotide from the PAM is incorporated as the last nucleotide of the repeat during integration of a new spacer. When multiple spacers were integrated in a single clone, all spacer targeted the same strand of the plasmid, implying that CRISPR interference caused by the first integrated spacer directs subsequent spacer acquisition events in a strand specific manner. CONCLUSIONS The E. coli Type I-E CRISPR/Cas system provides resistance against bacteriophage infection, but also enables removal of residing plasmids. We established that there is a positive feedback loop between active spacers in a cluster--in our case the first acquired spacer--and spacers acquired thereafter, possibly through the use of specific DNA degradation products of the CRISPR interference machinery by the CRISPR adaptation machinery. This loop enables a rapid expansion of the spacer repertoire against an actively present DNA element that is already targeted, amplifying the CRISPR interference effect.
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Affiliation(s)
- Daan C. Swarts
- Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - Cas Mosterd
- Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - Mark W. J. van Passel
- Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - Stan J. J. Brouns
- Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
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Westra ER, van Erp PBG, Künne T, Wong SP, Staals RHJ, Seegers CLC, Bollen S, Jore MM, Semenova E, Severinov K, de Vos WM, Dame RT, de Vries R, Brouns SJJ, van der Oost J. CRISPR immunity relies on the consecutive binding and degradation of negatively supercoiled invader DNA by Cascade and Cas3. Mol Cell 2012; 46:595-605. [PMID: 22521689 DOI: 10.1016/j.molcel.2012.03.018] [Citation(s) in RCA: 403] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/06/2012] [Accepted: 03/16/2012] [Indexed: 12/11/2022]
Abstract
The prokaryotic CRISPR/Cas immune system is based on genomic loci that contain incorporated sequence tags from viruses and plasmids. Using small guide RNA molecules, these sequences act as a memory to reject returning invaders. Both the Cascade ribonucleoprotein complex and the Cas3 nuclease/helicase are required for CRISPR interference in Escherichia coli, but it is unknown how natural target DNA molecules are recognized and neutralized by their combined action. Here we show that Cascade efficiently locates target sequences in negatively supercoiled DNA, but only if these are flanked by a protospacer-adjacent motif (PAM). PAM recognition by Cascade exclusively involves the crRNA-complementary DNA strand. After Cascade-mediated R loop formation, the Cse1 subunit recruits Cas3, which catalyzes nicking of target DNA through its HD-nuclease domain. The target is then progressively unwound and cleaved by the joint ATP-dependent helicase activity and Mg(2+)-dependent HD-nuclease activity of Cas3, leading to complete target DNA degradation and invader neutralization.
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Affiliation(s)
- Edze R Westra
- Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
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Characterization of the CRISPR/Cas subtype I-A system of the hyperthermophilic crenarchaeon Thermoproteus tenax. J Bacteriol 2012; 194:2491-500. [PMID: 22408157 DOI: 10.1128/jb.00206-12] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeats) elements and cas (CRISPR-associated) genes are widespread in Bacteria and Archaea. The CRISPR/Cas system operates as a defense mechanism against mobile genetic elements (i.e., viruses or plasmids). Here, we investigate seven CRISPR loci in the genome of the crenarchaeon Thermoproteus tenax that include spacers with significant similarity not only to archaeal viruses but also to T. tenax genes. The analysis of CRISPR RNA (crRNA) transcription reveals transcripts of a length between 50 and 130 nucleotides, demonstrating the processing of larger crRNA precursors. The organization of identified cas genes resembles CRISPR/Cas subtype I-A, and the core cas genes are shown to be arranged on two polycistronic transcripts: cascis (cas4, cas1/2, and csa1) and cascade (csa5, cas7, cas5a, cas3, cas3', and cas8a2). Changes in the environmental parameters such as UV-light exposure or high ionic strength modulate cas gene transcription. Two reconstitution protocols were established for the production of two discrete multipartite Cas protein complexes that correspond to their operonic gene arrangement. These data provide insights into the specialized mechanisms of an archaeal CRISPR/Cas system and allow selective functional analyses of Cas protein complexes in the future.
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46
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Abstract
Acquisition of foreign DNA can be of advantage or disadvantage to the host cell. New DNAs can increase the fitness of an organism to certain environmental conditions; however, replication and maintenance of incorporated nucleotide sequences can be a burden for the host cell. These circumstances have resulted in the development of certain cellular mechanisms limiting horizontal gene transfer, including the immune system of vertebrates or RNA interference mechanisms in eukaryotes. Also, in prokaryotes, specific systems have been characterized, which are aimed especially at limiting the invasion of bacteriophage DNA, for example, adsorption inhibition, injection blocking, restriction/modification, or abortive infection. Quite recently, another distinct mechanism limiting horizontal transfer of genetic elements has been identified in procaryotes and shown to protect microbial cells against exogenous nucleic acids of phage or plasmid origin. This system has been termed CRISPR/cas and consists of two main components: (i) the CRISPR (clustered, regularly interspaced short palindromic regions) locus and (ii) cas genes, encoding CRISPR-associated (Cas) proteins. In simplest words, the mechanism of CRISPR/cas activity is based on the active integration of small fragments (proto-spacers) of the invading DNAs (phage or plasmids) into microbial genomes, which are subsequently transcribed into short RNAs that direct the degradation of foreign invading DNA elements. In this way, the host organism acquires immunity toward mobile elements carrying matching sequences. The CRISPR/cas system is regarded as one of the earliest defense system that has evolved in prokaryotic organisms. It is inheritable, but at the same time is unstable when regarding the evolutionary scale. Comparative sequence analyses indicate that CRISPR/cas systems play an important role in the evolution of microbial genomes and their predators, bacteriophages.
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47
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Beloglazova N, Petit P, Flick R, Brown G, Savchenko A, Yakunin AF. Structure and activity of the Cas3 HD nuclease MJ0384, an effector enzyme of the CRISPR interference. EMBO J 2011; 30:4616-27. [PMID: 22009198 DOI: 10.1038/emboj.2011.377] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/22/2011] [Indexed: 12/24/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPRs) and Cas proteins represent an adaptive microbial immunity system against viruses and plasmids. Cas3 proteins have been proposed to play a key role in the CRISPR mechanism through the direct cleavage of invasive DNA. Here, we show that the Cas3 HD domain protein MJ0384 from Methanocaldococcus jannaschii cleaves endonucleolytically and exonucleolytically (3'-5') single-stranded DNAs and RNAs, as well as 3'-flaps, splayed arms, and R-loops. The degradation of branched DNA substrates by MJ0384 is stimulated by the Cas3 helicase MJ0383 and ATP. The crystal structure of MJ0384 revealed the active site with two bound metal cations and together with site-directed mutagenesis suggested a catalytic mechanism. Our studies suggest that the Cas3 HD nucleases working together with the Cas3 helicases can completely degrade invasive DNAs through the combination of endo- and exonuclease activities.
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Affiliation(s)
- Natalia Beloglazova
- Department of Chemical Engineering and Applied Chemistry, Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada
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Structure and activity of the Cas3 HD nuclease MJ0384, an effector enzyme of the CRISPR interference. EMBO J 2011. [PMID: 22009198 DOI: 10.1038/emboj.2011.377.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPRs) and Cas proteins represent an adaptive microbial immunity system against viruses and plasmids. Cas3 proteins have been proposed to play a key role in the CRISPR mechanism through the direct cleavage of invasive DNA. Here, we show that the Cas3 HD domain protein MJ0384 from Methanocaldococcus jannaschii cleaves endonucleolytically and exonucleolytically (3'-5') single-stranded DNAs and RNAs, as well as 3'-flaps, splayed arms, and R-loops. The degradation of branched DNA substrates by MJ0384 is stimulated by the Cas3 helicase MJ0383 and ATP. The crystal structure of MJ0384 revealed the active site with two bound metal cations and together with site-directed mutagenesis suggested a catalytic mechanism. Our studies suggest that the Cas3 HD nucleases working together with the Cas3 helicases can completely degrade invasive DNAs through the combination of endo- and exonuclease activities.
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