1
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Zheng C, Liang H, Dai L, Yu J, Long C. Dissecting the CRISPR Cas1-Cas2 Protospacer Binding and Selection Mechanism by Using Molecular Dynamics Simulations. J Phys Chem B 2024; 128:3563-3574. [PMID: 38573978 DOI: 10.1021/acs.jpcb.3c07320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Cas1 and Cas2 are highly conserved proteins among the clustered regularly interspaced short palindromic repeat Cas (CRISPR-Cas) systems and play a crucial role in protospacer selection and integration. According to the double-forked CRISPR Cas1-Cas2 complex, we conducted extensive all-atom molecular dynamics simulations to investigate the protospacer DNA binding and recognition. Our findings revealed that single-point amino acid mutations in Cas1 or in Cas2 had little impact on the binding of the protospacer, both in the binding and precatalytic states. In contrast, multiple-point amino acid mutations, particularly G74A, P80L, and V89A mutations on Cas2 and Cas2' proteins (m-multiple1 system), significantly affected the protospacer binding and selection. Notably, mutations on Cas2 and Cas2' led to an increased number of hydrogen bonds (#HBs) between Cas2&Cas2' and the dsDNA in the m-multiple1 system compared with the wild-type system. And the strong electrostatic interactions between Cas1-Cas2 and the protospacer DNA (psDNA) in the m-multiple1 system again suggested the increase in the binding affinity of protospacer acquisition. Specifically, mutations in Cas2 and Cas2' can remotely make the protospacer adjacent motif complementary (PAMc) sequences better in recognition by the two active sites, while multiple mutations K211E, P202Q, P212L, R138L, V134A, A286T, P282H, and P294H on Cas1a/Cas1b&Cas1a'/Cas1b' (m-multiple2 system) decrease the #HBs and the electrostatic interactions and make the PAMc worse in recognition compared with the wild-type system.
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Affiliation(s)
- Chuanbo Zheng
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Hongqiong Liang
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Liqiang Dai
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325001, China
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, California 92697, United States
| | - Chunhong Long
- School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
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2
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Cui Y, Qu X. CRISPR-Cas systems of lactic acid bacteria and applications in food science. Biotechnol Adv 2024; 71:108323. [PMID: 38346597 DOI: 10.1016/j.biotechadv.2024.108323] [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: 08/14/2023] [Revised: 12/29/2023] [Accepted: 02/09/2024] [Indexed: 02/17/2024]
Abstract
CRISPR-Cas (Clustered regularly interspaced short palindromic repeats-CRISPR associated proteins) systems are widely distributed in lactic acid bacteria (LAB), contributing to their RNA-mediated adaptive defense immunity. The CRISPR-Cas-based genetic tools have exhibited powerful capability. It has been highly utilized in different organisms, accelerating the development of life science. The review summarized the components, adaptive immunity mechanisms, and classification of CRISPR-Cas systems; analyzed the distribution and characteristics of CRISPR-Cas system in LAB. The review focuses on the development of CRISPR-Cas-based genetic tools in LAB for providing latest development and future trend. The diverse and broad applications of CRISPR-Cas systems in food/probiotic industry are introduced. LAB harbor a plenty of CRISPR-Cas systems, which contribute to generate safer and more robust strains with increased resistance against bacteriophage and prevent the dissemination of plasmids carrying antibiotic-resistance markers. Furthermore, the CRISPR-Cas system from LAB could be used to exploit novel, flexible, programmable genome editing tools of native host and other organisms, resolving the limitation of genetic operation of some LAB species, increasing the important biological functions of probiotics, improving the adaptation of probiotics in complex environments, and inhibiting the growth of foodborne pathogens. The development of the genetic tools based on CRISPR-Cas system in LAB, especially the endogenous CRISPR-Cas system, will open new avenues for precise regulation, rational design, and flexible application of LAB.
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Affiliation(s)
- Yanhua Cui
- Department of Food Nutrition and Health, School of Medicine and Health, Harbin Institute of Technology, Harbin 150001, China.
| | - Xiaojun Qu
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin, 150010, China
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3
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Su X, Jin X, Wang Z, Duan S. Unraveling Exogenous DNA Processing in Cas4-Lacking Crispr Systems: A Novel Bypass Pathway Explored. Adv Biol (Weinh) 2024; 8:e2300454. [PMID: 38072634 DOI: 10.1002/adbi.202300454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 11/09/2023] [Indexed: 03/16/2024]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems are widely distributed adaptive immune systems found in prokaryotes. The process involves three main stages: adaptation, expression, and interference. While the adaptation stage has been extensively studied, there is still an incomplete understanding of the mechanisms underlying the capture, trimming, and integration of exogenous DNA. For instance, Cas4, a CRISPR-Cas protein with endonuclease activity, is responsible for selecting and processing protospacer adjacent motif (PAM) sequences. However, some CRISPR isoforms lack Cas4 activity, relying on other enzymes for adaptive immunity. Recently, Wang et al. presented a novel model of exogenous DNA processing in a type I-E CRISPR system lacking Cas4 in a Nature article. This model integrates protospacer processing into CRISPR arrays through fine-tuned synthases formed by DnaQ-like exonuclease (DEDDh) and Cas1-Cas2 complexes. Their study introduces a novel model, shedding new light on the evolution of CRISPR adaptive immunity. This perspective comprehensively examines the fundamental process of CRISPR adaptive immunity, detailing both the classical pathway mediated by Cas4 and the alternative pathway mediated by DEDDh. Furthermore, a thorough evaluation of Wang et al.'s work is conducted, highlighting its strengths, weaknesses, and existing research challenges.
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Affiliation(s)
- Xinming Su
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
- Department of Clinical Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
| | - Xiaoyu Jin
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
- Department of Clinical Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
| | - Zehua Wang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
- Department of Clinical Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
| | - Shiwei Duan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
- Department of Clinical Medicine, Hangzhou City University, Hangzhou, Zhejiang, 310000, China
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4
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Kong H, Yi K, Mintz RL, Wang B, Xu Y, Lao YH, Tao Y, Li M. CRISPR/Cas detection with nanodevices: moving deeper into liquid biopsy. Chem Commun (Camb) 2024; 60:2301-2319. [PMID: 38251733 DOI: 10.1039/d3cc05375j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
The emerging field of liquid biopsy has garnered significant interest in precision diagnostics, offering a non-invasive and repetitive method for analyzing bodily fluids to procure real-time diagnostic data. The precision and accuracy offered by the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (CRISPR/Cas) technology have advanced and broadened the applications of liquid biopsy. Significantly, when combined with swiftly advancing nanotechnology, CRISPR/Cas-mediated nanodevices show vast potential in precise liquid biopsy applications. However, persistent challenges are still associated with off-target effects, and the current platforms also constrain the performance of the assays. In this review, we highlight the merits of CRISPR/Cas systems in liquid biopsy, tracing the development of CRISPR/Cas systems and their current applications in disease diagnosis particularly in liquid biopsies. We also outline ongoing efforts to design nanoscale devices with improved sensing and readout capabilities, aiming to enhance the performance of CRISPR/Cas detectors in liquid biopsy. Finally, we identify the critical obstacles hindering the widespread adoption of CRISPR/Cas liquid biopsy and explore potential solutions. This feature article presents a comprehensive overview of CRISPR/Cas-mediated liquid biopsies, emphasizing the progress in integrating nanodevices to improve specificity and sensitivity. It also sheds light on future research directions in employing nanodevices for CRISPR/Cas-based liquid biopsies in the realm of precision medicine.
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Affiliation(s)
- Huimin Kong
- Laboratory of Biomaterials and Translational Medicine, Center for Nanomedicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
| | - Ke Yi
- Laboratory of Biomaterials and Translational Medicine, Center for Nanomedicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
| | - Rachel L Mintz
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Bin Wang
- Department of Infectious Diseases, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun 130061, China
| | - Yanteng Xu
- Laboratory of Biomaterials and Translational Medicine, Center for Nanomedicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
| | - Yeh-Hsing Lao
- Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, 14214, USA
| | - Yu Tao
- Laboratory of Biomaterials and Translational Medicine, Center for Nanomedicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
| | - Mingqiang Li
- Laboratory of Biomaterials and Translational Medicine, Center for Nanomedicine, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
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5
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Mojtaba Mousavi S, Alireza Hashemi S, Yari Kalashgrani M, Rahmanian V, Riazi M, Omidifar N, Hamed Althomali R, Rahman MM, Chiang WH, Gholami A. Recent Progress in Prompt Molecular Detection of Exosomes Using CRISPR/Cas and Microfluidic-Assisted Approaches Toward Smart Cancer Diagnosis and Analysis. ChemMedChem 2024; 19:e202300359. [PMID: 37916531 DOI: 10.1002/cmdc.202300359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/28/2023] [Accepted: 11/01/2023] [Indexed: 11/03/2023]
Abstract
Exosomes are essential indicators of molecular mechanisms involved in interacting with cancer cells and the tumor environment. As nanostructures based on lipids and nucleic acids, exosomes provide a communication pathway for information transfer by transporting biomolecules from the target cell to other cells. Importantly, these extracellular vesicles are released into the bloodstream by the most invasive cells, i. e., cancer cells; in this way, they could be considered a promising specific biomarker for cancer diagnosis. In this matter, CRISPR-Cas systems and microfluidic approaches could be considered practical tools for cancer diagnosis and understanding cancer biology. CRISPR-Cas systems, as a genome editing approach, provide a way to inactivate or even remove a target gene from the cell without affecting intracellular mechanisms. These practical systems provide vital information about the factors involved in cancer development that could lead to more effective cancer treatment. Meanwhile, microfluidic approaches can also significantly benefit cancer research due to their proper sensitivity, high throughput, low material consumption, low cost, and advanced spatial and temporal control. Thereby, employing CRISPR-Cas- and microfluidics-based approaches toward exosome monitoring could be considered a valuable source of information for cancer therapy and diagnosis. This review assesses the recent progress in these promising diagnosis approaches toward accurate cancer therapy and in-depth study of cancer cell behavior.
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Affiliation(s)
- Seyyed Mojtaba Mousavi
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City, 106335, Taiwan
| | - Seyyed Alireza Hashemi
- Health Policy Research Center, Health Institute, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Vahid Rahmanian
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, Lodz, 90-363, Poland
| | - Mohsen Riazi
- Biotechnology Research Center, Shiraz University of Medical Science, Shiraz, 71468-64685, Iran
| | - Navid Omidifar
- Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Mohammed M Rahman
- Center of Excellence for Advanced Materials Research (CEAMR) & Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
| | - Wei-Hung Chiang
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City, 106335, Taiwan
| | - Ahmad Gholami
- Biotechnology Research Center, Shiraz University of Medical Science, Shiraz, 71468-64685, Iran
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6
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Tang D, Jia T, Luo Y, Mou B, Cheng J, Qi S, Yao S, Su Z, Yu Y, Chen Q. DnaQ mediates directional spacer acquisition in the CRISPR-Cas system by a time-dependent mechanism. Innovation (N Y) 2023; 4:100495. [PMID: 37663930 PMCID: PMC10470216 DOI: 10.1016/j.xinn.2023.100495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/06/2023] [Indexed: 09/05/2023] Open
Abstract
In the spacer acquisition stage of CRISPR-Cas immunity, spacer orientation and protospacer adjacent motif (PAM) removal are two prerequisites for functional spacer integration. Cas4 has been implicated in both processing the prespacer and determining the spacer orientation. In Cas4-lacking systems, host 3'-5' DnaQ family exonucleases were recently reported to play a Cas4-like role. However, the molecular details of DnaQ functions remain elusive. Here, we characterized the spacer acquisition of the adaptation module of the Streptococcus thermophilus type I-E system, in which a DnaQ domain naturally fuses with Cas2. We presented X-ray crystal structures and cryo-electron microscopy structures of this adaptation module. Our biochemical data showed that DnaQ trimmed PAM-containing and PAM-deficient overhangs with different efficiencies. Based on these results, we proposed a time-dependent model for DnaQ-mediated spacer acquisition to elucidate PAM removal and spacer orientation determination in Cas4-lacking CRISPR-Cas systems.
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Affiliation(s)
- Dongmei Tang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tingting Jia
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yongbo Luo
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Biqin Mou
- Precision Medicine Center, Precision Medicine Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jie Cheng
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shaohua Yao
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhaoming Su
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yamei Yu
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qiang Chen
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China
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7
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Dhingra Y, Sashital DG. Cas4/1 dual nuclease activities enable prespacer maturation and directional integration in a type I-G CRISPR-Cas system. J Biol Chem 2023; 299:105178. [PMID: 37607619 PMCID: PMC10504553 DOI: 10.1016/j.jbc.2023.105178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/12/2023] [Accepted: 08/15/2023] [Indexed: 08/24/2023] Open
Abstract
CRISPR-Cas adaptive immune systems uptake short "spacer" sequences from foreign DNA and incorporate them into the host genome to serve as templates for CRISPR RNAs that guide interference against future infections. Adaptation in CRISPR systems is mediated by Cas1-Cas2 complexes that catalyze integration of prespacer substrates into the CRISPR array. Many DNA targeting systems also require Cas4 endonucleases for functional spacer acquisition. Cas4 selects prespacers containing a protospacer adjacent motif (PAM) and removes the PAM prior to integration, both of which are required to ensure host immunization. Cas1 has also been shown to function as a nuclease in some systems, but a role for this nuclease activity in adaptation has not been demonstrated. We identified a type I-G Cas4/1 fusion with a nucleolytically active Cas1 domain that can directly participate in prespacer processing. The Cas1 domain is both an integrase and a sequence-independent nuclease that cleaves the non-PAM end of a prespacer, generating optimal overhang lengths that enable integration at the leader side. The Cas4 domain sequence specifically cleaves the PAM end of the prespacer, ensuring integration of the PAM end at the spacer side. The two domains have varying metal ion requirements. While Cas4 activity is Mn2+ dependent, Cas1 preferentially uses Mg2+ over Mn2+. The dual nuclease activity of Cas4/1 eliminates the need for additional factors in prespacer processing making the adaptation module self-reliant for prespacer maturation and directional integration.
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Affiliation(s)
- Yukti Dhingra
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Dipali G Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, Iowa, USA.
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8
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Wang JY, Tuck OT, Skopintsev P, Soczek KM, Li G, Al-Shayeb B, Zhou J, Doudna JA. Genome expansion by a CRISPR trimmer-integrase. Nature 2023:10.1038/s41586-023-06178-2. [PMID: 37316664 DOI: 10.1038/s41586-023-06178-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 05/08/2023] [Indexed: 06/16/2023]
Abstract
CRISPR-Cas adaptive immune systems capture DNA fragments from invading mobile genetic elements and integrate them into the host genome to provide a template for RNA-guided immunity1. CRISPR systems maintain genome integrity and avoid autoimmunity by distinguishing between self and non-self, a process for which the CRISPR/Cas1-Cas2 integrase is necessary but not sufficient2-5. In some microorganisms, the Cas4 endonuclease assists CRISPR adaptation6,7, but many CRISPR-Cas systems lack Cas48. Here we show here that an elegant alternative pathway in a type I-E system uses an internal DnaQ-like exonuclease (DEDDh) to select and process DNA for integration using the protospacer adjacent motif (PAM). The natural Cas1-Cas2/exonuclease fusion (trimmer-integrase) catalyses coordinated DNA capture, trimming and integration. Five cryo-electron microscopy structures of the CRISPR trimmer-integrase, visualized both before and during DNA integration, show how asymmetric processing generates size-defined, PAM-containing substrates. Before genome integration, the PAM sequence is released by Cas1 and cleaved by the exonuclease, marking inserted DNA as self and preventing aberrant CRISPR targeting of the host. Together, these data support a model in which CRISPR systems lacking Cas4 use fused or recruited9,10 exonucleases for faithful acquisition of new CRISPR immune sequences.
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Affiliation(s)
- Joy Y Wang
- Department of Chemistry, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Owen T Tuck
- Department of Chemistry, University of California, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Petr Skopintsev
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
| | - Katarzyna M Soczek
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA
| | - Gary Li
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, CA, USA
| | - Basem Al-Shayeb
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Julia Zhou
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Jennifer A Doudna
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, USA.
- Department of Bioengineering, University of California, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Gladstone Institutes, University of California, San Francisco, CA, USA.
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9
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Dhingra Y, Sashital DG. Cas4/1 dual nuclease activities enable prespacer maturation and directional integration in a type I-G CRISPR-Cas system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543779. [PMID: 37333257 PMCID: PMC10274657 DOI: 10.1101/2023.06.05.543779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
CRISPR-Cas adaptive immune systems uptake short 'spacer' sequences from foreign DNA and incorporate them into the host genome to serve as templates for crRNAs that guide interference against future infections. Adaptation in CRISPR systems is mediated by Cas1-Cas2 complexes that catalyze integration of prespacer substrates into the CRISPR array. Many DNA targeting systems also require Cas4 endonucleases for functional spacer acquisition. Cas4 selects prespacers containing a protospacer adjacent motif (PAM) and removes the PAM prior to integration, both of which are required to ensure host immunization. Cas1 has also been shown to function as a nuclease in some systems, but a role for this nuclease activity in adaptation has not been demonstrated. We identified a type I-G Cas4/1 fusion with a nucleolytically active Cas1 domain that can directly participate in prespacer processing. The Cas1 domain is both an integrase and a sequence-independent nuclease that cleaves the non-PAM end of a prespacer, generating optimal overhang lengths that enable integration at the leader side. The Cas4 domain sequence-specifically cleaves the PAM end of the prespacer, ensuring integration of the PAM end at the spacer side. The two domains have varying metal ion requirements. While Cas4 activity is Mn 2+ dependent, Cas1 preferentially uses Mg 2+ over Mn 2+ . The dual nuclease activity of Cas4/1 eliminates the need for additional factors in prespacer processing, making the adaptation module self-reliant for prespacer maturation and directional integration.
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Affiliation(s)
- Yukti Dhingra
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA, USA
| | - Dipali G. Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA, USA
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10
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Faure G, Saito M, Benler S, Peng I, Wolf YI, Strecker J, Altae-Tran H, Neumann E, Li D, Makarova KS, Macrae RK, Koonin EV, Zhang F. Modularity and diversity of target selectors in Tn7 transposons. Mol Cell 2023:S1097-2765(23)00367-2. [PMID: 37267947 DOI: 10.1016/j.molcel.2023.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/17/2023] [Accepted: 05/09/2023] [Indexed: 06/04/2023]
Abstract
To spread, transposons must integrate into target sites without disruption of essential genes while avoiding host defense systems. Tn7-like transposons employ multiple mechanisms for target-site selection, including protein-guided targeting and, in CRISPR-associated transposons (CASTs), RNA-guided targeting. Combining phylogenomic and structural analyses, we conducted a broad survey of target selectors, revealing diverse mechanisms used by Tn7 to recognize target sites, including previously uncharacterized target-selector proteins found in newly discovered transposable elements (TEs). We experimentally characterized a CAST I-D system and a Tn6022-like transposon that uses TnsF, which contains an inactivated tyrosine recombinase domain, to target the comM gene. Additionally, we identified a non-Tn7 transposon, Tsy, encoding a homolog of TnsF with an active tyrosine recombinase domain, which we show also inserts into comM. Our findings show that Tn7 transposons employ modular architecture and co-opt target selectors from various sources to optimize target selection and drive transposon spread.
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Affiliation(s)
- Guilhem Faure
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Makoto Saito
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sean Benler
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Iris Peng
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Jonathan Strecker
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Han Altae-Tran
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Edwin Neumann
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - David Li
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Rhiannon K Macrae
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA.
| | - Feng Zhang
- Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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11
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Zhang F, Neik TX, Thomas WJW, Batley J. CRISPR-Based Genome Editing Tools: An Accelerator in Crop Breeding for a Changing Future. Int J Mol Sci 2023; 24:ijms24108623. [PMID: 37239967 DOI: 10.3390/ijms24108623] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Genome editing is an important strategy to maintain global food security and achieve sustainable agricultural development. Among all genome editing tools, CRISPR-Cas is currently the most prevalent and offers the most promise. In this review, we summarize the development of CRISPR-Cas systems, outline their classification and distinctive features, delineate their natural mechanisms in plant genome editing and exemplify the applications in plant research. Both classical and recently discovered CRISPR-Cas systems are included, detailing the class, type, structures and functions of each. We conclude by highlighting the challenges that come with CRISPR-Cas and offer suggestions on how to tackle them. We believe the gene editing toolbox will be greatly enriched, providing new avenues for a more efficient and precise breeding of climate-resilient crops.
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Affiliation(s)
- Fangning Zhang
- College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Ting Xiang Neik
- School of Biosciences, University of Nottingham Malaysia, Semenyih 43500, Malaysia
| | - William J W Thomas
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Jacqueline Batley
- School of Biological Sciences, Institute of Agriculture, University of Western Australia, Perth, WA 6009, Australia
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12
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McBride TM, Cameron SC, Fineran PC, Fagerlund RD. The biology and type I/III hybrid nature of type I-D CRISPR-Cas systems. Biochem J 2023; 480:471-488. [PMID: 37052300 DOI: 10.1042/bcj20220073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 04/14/2023]
Abstract
Prokaryotes have adaptive defence mechanisms that protect them from mobile genetic elements and viral infection. One defence mechanism is called CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins). There are six different types of CRISPR-Cas systems and multiple subtypes that vary in composition and mode of action. Type I and III CRISPR-Cas systems utilise multi-protein complexes, which differ in structure, nucleic acid binding and cleaving preference. The type I-D system is a chimera of type I and III systems. Recently, there has been a burst of research on the type I-D CRISPR-Cas system. Here, we review the mechanism, evolution and biotechnological applications of the type I-D CRISPR-Cas system.
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Affiliation(s)
- Tess M McBride
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Shaharn C Cameron
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Robert D Fagerlund
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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13
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Fang L, Yang L, Han M, Xu H, Ding W, Dong X. CRISPR-cas technology: A key approach for SARS-CoV-2 detection. Front Bioeng Biotechnol 2023; 11:1158672. [PMID: 37214290 PMCID: PMC10198440 DOI: 10.3389/fbioe.2023.1158672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 03/31/2023] [Indexed: 05/24/2023] Open
Abstract
The CRISPR (Clustered Regularly Spaced Short Palindromic Repeats) system was first discovered in prokaryotes as a unique immune mechanism to clear foreign nucleic acids. It has been rapidly and extensively used in basic and applied research owing to its strong ability of gene editing, regulation and detection in eukaryotes. Hererin in this article, we reviewed the biology, mechanisms and relevance of CRISPR-Cas technology and its applications in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis. CRISPR-Cas nucleic acid detection tools include CRISPR-Cas9, CRISPR-Cas12, CRISPR-Cas13, CRISPR-Cas14, CRISPR nucleic acid amplification detection technology, and CRISPR colorimetric readout detection system. The above CRISPR technologies have been applied to the nucleic acid detection, including SARS-CoV-2 detection. Common nucleic acid detection based on CRISPR derivation technology include SHERLOCK, DETECTR, and STOPCovid. CRISPR-Cas biosensing technology has been widely applied to point-of-care testing (POCT) by targeting recognition of both DNA molecules and RNA Molecules.
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Affiliation(s)
- Lijuan Fang
- Department of Laboratory Medicine, Hangzhou Ninth People’s Hospital, Hangzhou, Zhejiang Province, China
| | - Lusen Yang
- Department of Laboratory Medicine, Hangzhou Ninth People’s Hospital, Hangzhou, Zhejiang Province, China
| | - Mingyue Han
- Department of Laboratory Medicine, Hangzhou Ninth People’s Hospital, Hangzhou, Zhejiang Province, China
| | - Huimei Xu
- Department of Laboratory Medicine, Hangzhou Ninth People’s Hospital, Hangzhou, Zhejiang Province, China
| | - Wenshuai Ding
- Department of Laboratory Medicine, Hangzhou Ninth People’s Hospital, Hangzhou, Zhejiang Province, China
| | - Xuejun Dong
- Medical Laboratory, Zhejiang University Shaoxing Hospital, Shaoxing, China
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14
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Rasmussen TS, Koefoed AK, Deng L, Muhammed MK, Rousseau GM, Kot W, Sprotte S, Neve H, Franz CMAP, Hansen AK, Vogensen FK, Moineau S, Nielsen DS. CRISPR-Cas provides limited phage immunity to a prevalent gut bacterium in gnotobiotic mice. THE ISME JOURNAL 2023; 17:432-442. [PMID: 36631688 PMCID: PMC9938214 DOI: 10.1038/s41396-023-01358-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023]
Abstract
Many bacteria and archaea harbor the adaptive CRISPR-Cas system, which stores small nucleotide fragments from previous invasions of nucleic acids via viruses or plasmids. This molecular archive blocks further invaders carrying identical or similar nucleotide sequences. However, few of these systems have been confirmed experimentally to be active in gut bacteria. Here, we demonstrate experimentally that the type I-C CRISPR-Cas system of the prevalent gut bacterium Eggerthella lenta can specifically target and cleave foreign DNA in vitro by using a plasmid transformation assay. We also show that the CRISPR-Cas system acquires new immunities (spacers) from the genome of a virulent E. lenta phage using traditional phage assays in vitro but also in vivo using gnotobiotic (GB) mice. Both high phage titer and an increased number of spacer acquisition events were observed when E. lenta was exposed to a low multiplicity of infection in vitro, and three phage genes were found to contain protospacer hotspots. Fewer new spacer acquisitions were detected in vivo than in vitro. Longitudinal analysis of phage-bacteria interactions showed sustained coexistence in the gut of GB mice, with phage abundance being approximately one log higher than the bacteria. Our findings show that while the type I-C CRISPR-Cas system is active in vitro and in vivo, a highly virulent phage in vitro was still able to co-exist with its bacterial host in vivo. Taken altogether, our results suggest that the CRISPR-Cas defense system of E. lenta provides only partial immunity in the gut.
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Affiliation(s)
- Torben Sølbeck Rasmussen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark.
| | - Anna Kirstine Koefoed
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Ling Deng
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Musemma K Muhammed
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Geneviève M Rousseau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de 1enie, Université Laval, Québec, QC, G1V 0A6, Canada
- Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Witold Kot
- Section of Microbial Ecology and Biotechnology, Department of Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg, Denmark
| | - Sabrina Sprotte
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Charles M A P Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Axel Kornerup Hansen
- Section of Experimental Animal Models, Department of Veterinary and Animal Sciences, University of Copenhagen, 1871, Frederiksberg, Denmark
| | - Finn Kvist Vogensen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Sylvain Moineau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de 1enie, Université Laval, Québec, QC, G1V 0A6, Canada
- Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
- Félix d'Hérelle Reference Center for Bacterial Viruses, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Dennis Sandris Nielsen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark.
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15
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Hsieh SC, Peters JE. Discovery and characterization of novel type I-D CRISPR-guided transposons identified among diverse Tn7-like elements in cyanobacteria. Nucleic Acids Res 2023; 51:765-782. [PMID: 36537206 PMCID: PMC9881144 DOI: 10.1093/nar/gkac1216] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
CRISPR-Cas defense systems have been naturally coopted for guide RNA-directed transposition by Tn7 family bacterial transposons. We find cyanobacterial genomes are rich in Tn7-like elements, including most of the known guide RNA-directed transposons, the type V-K, I-B1, and I-B2 CRISPR-Cas based systems. We discovered and characterized an example of a type I-D CRISPR-Cas system which was naturally coopted for guide RNA-directed transposition. Multiple novel adaptations were found specific to the I-D subtype, including natural inactivation of the Cas10 nuclease. The type I-D CRISPR-Cas transposition system showed flexibility in guide RNA length requirements and could be engineered to function with ribozyme-based self-processing guide RNAs removing the requirement for Cas6 in the heterologous system. The type I-D CRISPR-Cas transposon also has naturally fused transposase proteins that are functional for cut-and-paste transposition. Multiple attributes of the type I-D system offer unique possibilities for future work in gene editing. Our bioinformatic analysis also revealed a broader understanding of the evolution of Tn7-like elements. Extensive swapping of targeting systems was identified among Tn7-like elements in cyanobacteria and multiple examples of convergent evolution, including systems targeting integration into genes required for natural transformation.
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Affiliation(s)
- Shan-Chi Hsieh
- Department of Microbiology, Cornell University, Ithaca, NY 14853 USA
| | - Joseph E Peters
- Department of Microbiology, Cornell University, Ithaca, NY 14853 USA
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16
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Smaruj P, Kieliszek M. Casposons - silent heroes of the CRISPR-Cas systems evolutionary history. EXCLI JOURNAL 2023; 22:70-83. [PMID: 36814855 PMCID: PMC9939771 DOI: 10.17179/excli2022-5581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/19/2022] [Indexed: 02/24/2023]
Abstract
Many archaeal and bacterial organisms possess an adaptive immunity system known as CRISPR-Cas. Its role is to recognize and degrade foreign DNA showing high similarity to repeats within the CRISPR array. In recent years computational techniques have been used to identify cas1 genes that are not associated with CRISPR systems, named cas1-solo. Often, cas1-solo genes are present in a conserved neighborhood of PolB-like polymerase genes, which is a characteristic feature of self-synthesizing, eukaryotic transposons of the Polinton class. Nearly all cas1-polB genomic islands are flanked by terminal inverted repeats and direct repeats which correspond to target site duplications. Considering the patchy taxonomic distribution of the identified islands in archaeal and bacterial genomes, they were characterized as a new superfamily of mobile genetic elements and called casposons. Here, we review recent experiments on casposons' mobility and discuss their discovery, classification, and evolutionary relationship with the CRISPR-Cas systems.
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Affiliation(s)
- Paulina Smaruj
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, United States of America,College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 02-097 Warsaw, Poland,*To whom correspondence should be addressed: Paulina Smaruj, Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, United States of America, E-mail:
| | - Marek Kieliszek
- Department of Food Biotechnology and Microbiology, Institute of Food Sciences, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159 C, 02-776 Warsaw, Poland
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17
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Flusche T, Rajan R. Molecular Details of DNA Integration by CRISPR-Associated Proteins During Adaptation in Bacteria and Archaea. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1414:27-43. [PMID: 35852729 DOI: 10.1007/5584_2022_730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins constitute an adaptive immune system in bacteria and archaea, where immunological memory is retained in the CRISPR locus as short pieces of the intruding nucleic acid, termed spacers. The adaptation to new infections occurs through the integration of a new spacer into the CRISPR array. For immune protection, spacers are transcribed into CRISPR RNAs (crRNA) that are used to guide the effector nuclease of the system in sequence-dependent target cleavage. Spacers originate as a prespacer from either DNA or RNA depending on the CRISPR-Cas system being observed, and the nearly universal Cas proteins, Cas1 and Cas2, insert the prespacer into the CRISPR locus during adaptation in all systems that contain them. The mechanism of site-specific prespacer integration varies across CRISPR classes and types, and distinct differences can even be found within the same subtype. In this review, the current knowledge on the mechanisms of prespacer integration in type II-A CRISPR-Cas systems will be described. Comparisons of the currently characterized type II-A systems show that distinct mechanisms exist within different members of this subtype and are correlated to sequence-specific interactions of Cas proteins and the DNA elements present in the CRISPR array. These observations indicate that nature has fine-tuned the mechanistic details while performing the basic step of DNA integration by Cas proteins, which offers unique advantages to develop Cas1-Cas2-based biotechnology.
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Affiliation(s)
- Tamara Flusche
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, USA
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, USA.
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18
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Dhingra Y, Suresh SK, Juneja P, Sashital DG. PAM binding ensures orientational integration during Cas4-Cas1-Cas2-mediated CRISPR adaptation. Mol Cell 2022; 82:4353-4367.e6. [PMID: 36272411 PMCID: PMC9675710 DOI: 10.1016/j.molcel.2022.09.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/10/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022]
Abstract
Adaptation in CRISPR-Cas systems immunizes bacteria and archaea against mobile genetic elements. In many DNA-targeting systems, the Cas4-Cas1-Cas2 complex is required for selection and processing of DNA segments containing PAM sequences prior to integration of these "prespacer" substrates as spacers in the CRISPR array. We determined cryo-EM structures of the Cas4-Cas1-Cas2 adaptation complex from the type I-C system that encodes standalone Cas1 and Cas4 proteins. The structures reveal how Cas4 specifically reads out bases within the PAM sequence and how interactions with both Cas1 and Cas2 activate Cas4 endonuclease activity. The Cas4-PAM interaction ensures tight binding between the adaptation complex and the prespacer, significantly enhancing integration of the non-PAM end into the CRISPR array and ensuring correct spacer orientation. Corroborated with our biochemical results, Cas4-Cas1-Cas2 structures with substrates representing various stages of CRISPR adaptation reveal a temporally resolved mechanism for maturation and integration of functional spacers into the CRISPR array.
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Affiliation(s)
- Yukti Dhingra
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA, USA
| | - Shravanti K Suresh
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA, USA
| | - Puneet Juneja
- Cryo-EM Facility, Office of Biotechnology, Iowa State University, Ames, IA, USA
| | - Dipali G Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA, USA.
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19
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Wang JY, Pausch P, Doudna JA. Structural biology of CRISPR-Cas immunity and genome editing enzymes. Nat Rev Microbiol 2022; 20:641-656. [PMID: 35562427 DOI: 10.1038/s41579-022-00739-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2022] [Indexed: 12/20/2022]
Abstract
CRISPR-Cas systems provide resistance against foreign mobile genetic elements and have a wide range of genome editing and biotechnological applications. In this Review, we examine recent advances in understanding the molecular structures and mechanisms of enzymes comprising bacterial RNA-guided CRISPR-Cas immune systems and deployed for wide-ranging genome editing applications. We explore the adaptive and interference aspects of CRISPR-Cas function as well as open questions about the molecular mechanisms responsible for genome targeting. These structural insights reflect close evolutionary links between CRISPR-Cas systems and mobile genetic elements, including the origins and evolution of CRISPR-Cas systems from DNA transposons, retrotransposons and toxin-antitoxin modules. We discuss how the evolution and structural diversity of CRISPR-Cas systems explain their functional complexity and utility as genome editing tools.
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Affiliation(s)
- Joy Y Wang
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Patrick Pausch
- VU LSC-EMBL Partnership for Genome Editing Technologies, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
| | - Jennifer A Doudna
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA.
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA, USA.
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA.
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20
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Wu WY, Jackson SA, Almendros C, Haagsma AC, Yilmaz S, Gort G, van der Oost J, Brouns SJJ, Staals RHJ. Adaptation by Type V-A and V-B CRISPR-Cas Systems Demonstrates Conserved Protospacer Selection Mechanisms Between Diverse CRISPR-Cas Types. CRISPR J 2022; 5:536-547. [PMID: 35833800 PMCID: PMC9419969 DOI: 10.1089/crispr.2021.0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Adaptation of clustered regularly interspaced short palindromic repeats (CRISPR) arrays is a crucial process responsible for the unique, adaptive nature of CRISPR-Cas immune systems. The acquisition of new CRISPR spacers from mobile genetic elements has previously been studied for several types of CRISPR-Cas systems. In this study, we used a high-throughput sequencing approach to characterize CRISPR adaptation of the type V-A system from Francisella novicida and the type V-B system from Alicyclobacillus acidoterrestris. In contrast to other class 2 CRISPR-Cas systems, we found that for the type V-A and V-B systems, the Cas12 nucleases are dispensable for spacer acquisition, with only Cas1 and Cas2 (type V-A) or Cas4/1 and Cas2 (type V-B) being necessary and sufficient. Whereas the catalytic activity of Cas4 is not essential for adaptation, Cas4 activity is required for correct protospacer adjacent motif selection in both systems and for prespacer trimming in type V-A. In addition, we provide evidence for acquisition of RecBCD-produced DNA fragments by both systems, but with spacers derived from foreign DNA being incorporated preferentially over those derived from the host chromosome. Our work shows that several spacer acquisition mechanisms are conserved between diverse CRISPR-Cas systems, but also highlights unexpected nuances between similar systems that generally contribute to a bias of gaining immunity against invading genetic elements.
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Affiliation(s)
- Wen Y Wu
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cristóbal Almendros
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Anna C Haagsma
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Suzan Yilmaz
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Gerrit Gort
- Biometris, Wageningen University and Research, Wageningen, The Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands.,Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Raymond H J Staals
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
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21
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Erdrich SH, Sharma V, Schurr U, Arsova B, Frunzke J. Isolation of Novel Xanthomonas Phages Infecting the Plant Pathogens X. translucens and X. campestris. Viruses 2022; 14:v14071449. [PMID: 35891434 PMCID: PMC9316219 DOI: 10.3390/v14071449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 12/18/2022] Open
Abstract
The genus of Xanthomonas contains many well-known plant pathogens with the ability to infect some of the most important crop plants, thereby causing significant economic damage. Unfortunately, classical pest-control strategies are neither particularly efficient nor sustainable and we are, therefore, in demand of alternatives. Here, we present the isolation and characterization of seven novel phages infecting the plant-pathogenic species Xanthomonas translucens and Xanthomonas campestris. Transmission electron microscopy revealed that all phages show a siphovirion morphology. The analysis of genome sequences and plaque morphologies are in agreement with a lytic lifestyle of the phages making them suitable candidates for biocontrol. Moreover, three of the isolated phages form the new genus “Shirevirus”. All seven phages belong to four distinct clusters underpinning their phylogenetic diversity. Altogether, this study presents the first characterized isolates for the plant pathogen X. translucens and expands the number of available phages for plant biocontrol.
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Affiliation(s)
- Sebastian H. Erdrich
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Vikas Sharma
- Institute of Bio- and Geosciences, Department for Biotechnology (IBG-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Ulrich Schurr
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Borjana Arsova
- Institute of Bio- and Geosciences, Department for Plant Sciences (IBG-2), Forschungszentrum Jülich, 52425 Jülich, Germany; (S.H.E.); (U.S.); (B.A.)
| | - Julia Frunzke
- Institute of Bio- and Geosciences, Department for Biotechnology (IBG-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
- Correspondence: ; Tel.: +49-2461-615430
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22
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Structural rearrangements allow nucleic acid discrimination by type I-D Cascade. Nat Commun 2022; 13:2829. [PMID: 35595728 PMCID: PMC9123187 DOI: 10.1038/s41467-022-30402-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/27/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems are adaptive immune systems that protect prokaryotes from foreign nucleic acids, such as bacteriophages. Two of the most prevalent CRISPR-Cas systems include type I and type III. Interestingly, the type I-D interference proteins contain characteristic features of both type I and type III systems. Here, we present the structures of type I-D Cascade bound to both a double-stranded (ds)DNA and a single-stranded (ss)RNA target at 2.9 and 3.1 Å, respectively. We show that type I-D Cascade is capable of specifically binding ssRNA and reveal how PAM recognition of dsDNA targets initiates long-range structural rearrangements that likely primes Cas10d for Cas3′ binding and subsequent non-target strand DNA cleavage. These structures allow us to model how binding of the anti-CRISPR protein AcrID1 likely blocks target dsDNA binding via competitive inhibition of the DNA substrate engagement with the Cas10d active site. This work elucidates the unique mechanisms used by type I-D Cascade for discrimination of single-stranded and double stranded targets. Thus, our data supports a model for the hybrid nature of this complex with features of type III and type I systems. I-D CRISPR-Cascade can target both single-stranded and double-stranded nucleic acids. Here, Schwartz et. al determine these structures and reveal large-scale rearrangements that allow for target discrimination and destruction.
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Zhang X, An X. Adaptation by Type III CRISPR-Cas Systems: Breakthrough Findings and Open Questions. Front Microbiol 2022; 13:876174. [PMID: 35495695 PMCID: PMC9048733 DOI: 10.3389/fmicb.2022.876174] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/03/2022] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems acquire heritable defense memory against invading nucleic acids through adaptation. Type III CRISPR-Cas systems have unique and intriguing features of defense and are important in method development for Genetics research. We started to understand the common and unique properties of type III CRISPR-Cas adaptation in recent years. This review summarizes our knowledge regarding CRISPR-Cas adaptation with the emphasis on type III systems and discusses open questions for type III adaptation studies.
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Affiliation(s)
- Xinfu Zhang
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, GA, United States
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- *Correspondence: Xinfu Zhang,
| | - Xinmin An
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Research Center of Tree breeding and Ecological Remediation, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- Xinmin An,
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24
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Lee H, Sashital DG. Creating memories: molecular mechanisms of CRISPR adaptation. Trends Biochem Sci 2022; 47:464-476. [DOI: 10.1016/j.tibs.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/22/2022]
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Dixit B, Prakash A, Kumar P, Gogoi P, Kumar M. The core Cas1 protein of CRISPR-Cas I-B in Leptospira shows metal-tunable nuclease activity. CURRENT RESEARCH IN MICROBIAL SCIENCES 2021; 2:100059. [PMID: 34841349 PMCID: PMC8610301 DOI: 10.1016/j.crmicr.2021.100059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/09/2021] [Accepted: 08/15/2021] [Indexed: 12/26/2022] Open
Abstract
Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 is the causative agent of leptospirosis in animals and humans. This organism carries a functional cas1 gene classified under CRISPR-Cas I-B. In this study, using various nuclease assays and bioinformatics analysis, we report that the recombinant Cas1 (LinCas1) possesses metal-ion dependent DNase activity, which is inhibited upon substitution or chelation of metal-ion and/or interaction with recombinant Cas2 (LinCas2) of L. interrogans. Model of LinCas1 structure shows a shorter N-terminal domain unlike other Cas1 orthologs reported to date. The C-terminal domain of LinCas1 contains conserved divalent-metal binding residues (Glu108, His176, and Glu191) and the mutation of these residues leads to abolition in DNase activity. Immunoassay using anti-LinCas2 demonstrates that LinCas1 interacts with LinCas2 and attains a saturation point. Moreover, the nuclease activity of the LinCas1-Cas2 mixture on ds-DNA displayed a reduction in activity compared to the pure core LinCas proteins under in vitro condition. The DNase activity for LinCas1 is consistent with a role for this protein in the recognition/cleavage of foreign DNA and integration of foreign DNA as spacer into the CRISPR array.
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Affiliation(s)
- Bhuvan Dixit
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Aman Prakash
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Pankaj Kumar
- Division of Livestock and Fisheries Management, ICAR Research Complex for Eastern Region, Patna, Bihar 800014, India
| | - Prerana Gogoi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Manish Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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Le Gratiet T, Le Marechal C, Devaere M, Chemaly M, Woudstra C. Exploration of the Diversity of Clustered Regularly Interspaced Short Palindromic Repeats-Cas Systems in Clostridium novyi sensu lato. Front Microbiol 2021; 12:711413. [PMID: 34589070 PMCID: PMC8473940 DOI: 10.3389/fmicb.2021.711413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
Classified as the genospecies Clostridium novyi sensu lato and distributed into four lineages (I-IV), Clostridium botulinum (group III), Clostridium novyi, and Clostridium haemolyticum are clostridial pathogens that cause animal diseases. Clostridium novyi sensu lato contains a large mobilome consisting of plasmids and circular bacteriophages. Here, we explored clustered regularly interspaced short palindromic repeats (CRISPR) arrays and their associated proteins (Cas) to shed light on the link between evolution of CRISPR-Cas systems and the plasmid and phage composition in a study of 58 Clostridium novyi sensu lato genomes. In 55 of these genomes, types I-B (complete or partial), I-D, II-C, III-B, III-D, or V-U CRISPR-Cas systems were detected in chromosomes as well as in mobile genetic elements (MGEs). Type I-B predominated (67.2%) and was the only CRISPR type detected in the Ia, III, and IV genomic lineages. Putative type V-U CRISPR Cas14a genes were detected in two different cases: next to partial type-IB CRISPR loci on the phage encoding the botulinum neurotoxin (BoNT) in lineage Ia and in 12 lineage II genomes, as part of a putative integrative element related to a phage-inducible chromosomal island (PICI). In the putative PICI, Cas14a was associated with CRISPR arrays and restriction modification (RM) systems as part of an accessory locus. This is the first time a PICI containing such locus has been detected in C. botulinum. Mobilome composition and dynamics were also investigated based on the contents of the CRISPR arrays and the study of spacers. A large proportion of identified protospacers (20.2%) originated from Clostridium novyi sensu lato (p1_Cst, p4_BKT015925, p6_Cst, CWou-2020a, p1_BKT015925, and p2_BKT015925), confirming active exchanges within this genospecies and the key importance of specific MGEs in Clostridium novyi sensu lato.
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Affiliation(s)
- Thibault Le Gratiet
- Hygiene and Quality of Poultry and Pig Products Unit, ANSES, French Agency for Food, Environmental and Occupational Health Safety, Ploufragan, France.,UFR of Life Sciences and Environment, University of Rennes, Rennes, France
| | - Caroline Le Marechal
- Hygiene and Quality of Poultry and Pig Products Unit, ANSES, French Agency for Food, Environmental and Occupational Health Safety, Ploufragan, France
| | - Marie Devaere
- Hygiene and Quality of Poultry and Pig Products Unit, ANSES, French Agency for Food, Environmental and Occupational Health Safety, Ploufragan, France
| | - Marianne Chemaly
- Hygiene and Quality of Poultry and Pig Products Unit, ANSES, French Agency for Food, Environmental and Occupational Health Safety, Ploufragan, France
| | - Cédric Woudstra
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
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Mechanism for Cas4-assisted directional spacer acquisition in CRISPR-Cas. Nature 2021; 598:515-520. [PMID: 34588691 PMCID: PMC9164213 DOI: 10.1038/s41586-021-03951-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 08/25/2021] [Indexed: 02/08/2023]
Abstract
Prokaryotes adapt to challenges from mobile genetic elements by integrating spacers derived from foreign DNA in the CRISPR array1. Spacer insertion is carried out by the Cas1-Cas2 integrase complex2-4. A substantial fraction of CRISPR-Cas systems use a Fe-S cluster containing Cas4 nuclease to ensure that spacers are acquired from DNA flanked by a protospacer adjacent motif (PAM)5,6 and inserted into the CRISPR array unidirectionally, so that the transcribed CRISPR RNA can guide target searching in a PAM-dependent manner. Here we provide a high-resolution mechanistic explanation for the Cas4-assisted PAM selection, spacer biogenesis and directional integration by type I-G CRISPR in Geobacter sulfurreducens, in which Cas4 is naturally fused with Cas1, forming Cas4/Cas1. During biogenesis, only DNA duplexes possessing a PAM-embedded 3'-overhang trigger Cas4/Cas1-Cas2 assembly. During this process, the PAM overhang is specifically recognized and sequestered, but is not cleaved by Cas4. This 'molecular constipation' prevents the PAM-side prespacer from participating in integration. Lacking such sequestration, the non-PAM overhang is trimmed by host nucleases and integrated to the leader-side CRISPR repeat. Half-integration subsequently triggers PAM cleavage and Cas4 dissociation, allowing spacer-side integration. Overall, the intricate molecular interaction between Cas4 and Cas1-Cas2 selects PAM-containing prespacers for integration and couples the timing of PAM processing with the stepwise integration to establish directionality.
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28
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Vink JNA, Baijens JHL, Brouns SJJ. PAM-repeat associations and spacer selection preferences in single and co-occurring CRISPR-Cas systems. Genome Biol 2021; 22:281. [PMID: 34593010 PMCID: PMC8482600 DOI: 10.1186/s13059-021-02495-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/09/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The adaptive CRISPR-Cas immune system stores sequences from past invaders as spacers in CRISPR arrays and thereby provides direct evidence that links invaders to hosts. Mapping CRISPR spacers has revealed many aspects of CRISPR-Cas biology, including target requirements such as the protospacer adjacent motif (PAM). However, studies have so far been limited by a low number of mapped spacers in the database. RESULTS By using vast metagenomic sequence databases, we map approximately one-third of more than 200,000 unique CRISPR spacers from a variety of microbes and derive a catalog of more than two hundred unique PAM sequences associated with specific CRISPR-Cas subtypes. These PAMs are further used to correctly assign the orientation of CRISPR arrays, revealing conserved patterns between the last nucleotides of the CRISPR repeat and PAM. We could also deduce CRISPR-Cas subtype-specific preferences for targeting either template or coding strand of open reading frames. While some DNA-targeting systems (type I-E and type II systems) prefer the template strand and avoid mRNA, other DNA- and RNA-targeting systems (types I-A and I-B and type III systems) prefer the coding strand and mRNA. In addition, we find large-scale evidence that both CRISPR-Cas adaptation machinery and CRISPR arrays are shared between different CRISPR-Cas systems. This could lead to simultaneous DNA and RNA targeting of invaders, which may be effective at combating mobile genetic invaders. CONCLUSIONS This study has broad implications for our understanding of how CRISPR-Cas systems work in a wide range of organisms for which only the genome sequence is known.
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Affiliation(s)
- Jochem N A Vink
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Jan H L Baijens
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands.
- Kavli Institute of Nanoscience, Delft, The Netherlands.
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29
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Guzmán NM, Esquerra-Ruvira B, Mojica FJM. Digging into the lesser-known aspects of CRISPR biology. Int Microbiol 2021; 24:473-498. [PMID: 34487299 PMCID: PMC8616872 DOI: 10.1007/s10123-021-00208-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/26/2022]
Abstract
A long time has passed since regularly interspaced DNA repeats were discovered in prokaryotes. Today, those enigmatic repetitive elements termed clustered regularly interspaced short palindromic repeats (CRISPR) are acknowledged as an emblematic part of multicomponent CRISPR-Cas (CRISPR associated) systems. These systems are involved in a variety of roles in bacteria and archaea, notably, that of conferring protection against transmissible genetic elements through an adaptive immune-like response. This review summarises the present knowledge on the diversity, molecular mechanisms and biology of CRISPR-Cas. We pay special attention to the most recent findings related to the determinants and consequences of CRISPR-Cas activity. Research on the basic features of these systems illustrates how instrumental the study of prokaryotes is for understanding biology in general, ultimately providing valuable tools for diverse fields and fuelling research beyond the mainstream.
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Affiliation(s)
- Noemí M Guzmán
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Belén Esquerra-Ruvira
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Francisco J M Mojica
- Dpto. Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain. .,Instituto Multidisciplinar para el Estudio del Medio, Universidad de Alicante, Alicante, Spain.
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30
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Liu Q, Wang S, Long J, Chen Z, Yang B, Lin F. Functional Identification of the Xanthomonas oryzae pv. oryzae Type I-C CRISPR-Cas System and Its Potential in Gene Editing Application. Front Microbiol 2021; 12:686715. [PMID: 34475857 PMCID: PMC8406640 DOI: 10.3389/fmicb.2021.686715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 07/26/2021] [Indexed: 12/19/2022] Open
Abstract
The type I clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system is one of five adaptive immune systems and exists widely in bacteria and archaea. In this study, we showed that Xanthomonas oryzae pv. oryzae (Xoo) possesses a functional CRISPR system by engineering constructs mimicking its CRISPR cassette. CRISPR array analysis showed that the TTC at the 5'-end of the target sequence is a functional protospacer-adjacent motif (PAM) of CRISPR. Guide RNA (gRNA) deletion analysis identified a minimum of 27-bp spacer that was required to ensure successful self-target killing in PXO99A strain. Mutants with deletion of individual Cas genes were constructed to analyze the effects of Cas proteins on mature CRISPR RNA (crRNA), processing intermediates and DNA interference. Results showed that depleting each of the three genes, cas5d, csd1, and csd2 inactivated the pre-crRNA processing, whereas inactivation of cas3 impaired in processing pre-crRNA. Furthermore, the Xoo CRISPR/Cas system was functional in Pseudomonas syringae pv. tomato. Collectively, our results would contribute to the functional study of CRISPR/Cas system of Xoo, and also provide a new vision on the use of bacterial endogenous systems as a convenient tool for gene editing.
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Affiliation(s)
- Qibing Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Siwei Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Juying Long
- Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Zhuoyue Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Bing Yang
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.,Donald Danforth Plant Science Center, St. Louis, MO, United States
| | - Fei Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
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31
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Maikova A, Boudry P, Shiriaeva A, Vasileva A, Boutserin A, Medvedeva S, Semenova E, Severinov K, Soutourina O. Protospacer-Adjacent Motif Specificity during Clostridioides difficile Type I-B CRISPR-Cas Interference and Adaptation. mBio 2021; 12:e0213621. [PMID: 34425703 PMCID: PMC8406132 DOI: 10.1128/mbio.02136-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems provide prokaryotes with efficient protection against foreign nucleic acid invaders. We have recently demonstrated the defensive interference function of a CRISPR-Cas system from Clostridioides (Clostridium) difficile, a major human enteropathogen, and showed that it could be harnessed for efficient genome editing in this bacterium. However, molecular details are still missing on CRISPR-Cas function for adaptation and sequence requirements for both interference and new spacer acquisition in this pathogen. Despite accumulating knowledge on the individual CRISPR-Cas systems in various prokaryotes, no data are available on the adaptation process in bacterial type I-B CRISPR-Cas systems. Here, we report the first experimental evidence that the C. difficile type I-B CRISPR-Cas system acquires new spacers upon overexpression of its adaptation module. The majority of new spacers are derived from a plasmid expressing Cas proteins required for adaptation or from regions of the C. difficile genome where generation of free DNA termini is expected. Results from protospacer-adjacent motif (PAM) library experiments and plasmid conjugation efficiency assays indicate that C. difficile CRISPR-Cas requires the YCN consensus PAM for efficient interference. We revealed a functional link between the adaptation and interference machineries, since newly adapted spacers are derived from sequences associated with a CCN PAM, which fits the interference consensus. The definition of functional PAMs and establishment of relative activity levels of each of the multiple C. difficile CRISPR arrays in present study are necessary for further CRISPR-based biotechnological and medical applications involving this organism. IMPORTANCE CRISPR-Cas systems provide prokaryotes with adaptive immunity for defense against foreign nucleic acid invaders, such as viruses or phages and plasmids. The CRISPR-Cas systems are highly diverse, and detailed studies of individual CRISPR-Cas subtypes are important for our understanding of various aspects of microbial adaptation strategies and for the potential applications. The significance of our work is in providing the first experimental evidence for type I-B CRISPR-Cas system adaptation in the emerging human enteropathogen Clostridioides difficile. This bacterium needs to survive in phage-rich gut communities, and its active CRISPR-Cas system might provide efficient antiphage defense by acquiring new spacers that constitute memory for further invader elimination. Our study also reveals a functional link between the adaptation and interference CRISPR machineries. The definition of all possible functional trinucleotide motifs upstream protospacers within foreign nucleic acid sequences is important for CRISPR-based genome editing in this pathogen and for developing new drugs against C. difficile infections.
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Affiliation(s)
- Anna Maikova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Pierre Boudry
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Anna Shiriaeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, Russia
| | - Aleksandra Vasileva
- Institute of Gene Biology, Centre for Precision Genome Editing and Genetic Technologies for Biomedicine, Russian Academy of Sciences, Moscow, Russia
| | - Anaïs Boutserin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Sofia Medvedeva
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ekaterina Semenova
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin Severinov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
- Institut Universitaire de France (IUF), Paris, France
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32
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Ma CH, Javanmardi K, Finkelstein IJ, Jayaram M. Disintegration promotes protospacer integration by the Cas1-Cas2 complex. eLife 2021; 10:65763. [PMID: 34435949 PMCID: PMC8390005 DOI: 10.7554/elife.65763] [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: 12/15/2020] [Accepted: 08/11/2021] [Indexed: 12/16/2022] Open
Abstract
‘Disintegration’—the reversal of transposon DNA integration at a target site—is regarded as an abortive off-pathway reaction. Here, we challenge this view with a biochemical investigation of the mechanism of protospacer insertion, which is mechanistically analogous to DNA transposition, by the Streptococcus pyogenes Cas1-Cas2 complex. In supercoiled target sites, the predominant outcome is the disintegration of one-ended insertions that fail to complete the second integration event. In linear target sites, one-ended insertions far outnumber complete protospacer insertions. The second insertion event is most often accompanied by the disintegration of the first, mediated either by the 3′-hydroxyl exposed during integration or by water. One-ended integration intermediates may mature into complete spacer insertions via DNA repair pathways that are also involved in transposon mobility. We propose that disintegration-promoted integration is functionally important in the adaptive phase of CRISPR-mediated bacterial immunity, and perhaps in other analogous transposition reactions.
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Affiliation(s)
- Chien-Hui Ma
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
| | - Kamyab Javanmardi
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, United States
| | - Makkuni Jayaram
- Department of Molecular Biosciences and Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, United States
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33
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Kieper SN, Almendros C, Haagsma AC, Barendregt A, Heck AJR, Brouns SJJ. Cas4-Cas1 Is a Protospacer Adjacent Motif-Processing Factor Mediating Half-Site Spacer Integration During CRISPR Adaptation. CRISPR J 2021; 4:536-548. [PMID: 34406043 DOI: 10.1089/crispr.2021.0011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The immunization of bacteria and archaea against invading viruses via CRISPR adaptation is critically reliant on the efficient capture, accurate processing, and integration of CRISPR spacers into the host genome. The adaptation proteins Cas1 and Cas2 are sufficient for successful spacer acquisition in some CRISPR-Cas systems. However, many CRISPR-Cas systems additionally require the Cas4 protein for efficient adaptation. Cas4 has been implied in the selection and processing of spacer precursors, but the detailed mechanistic understanding of how Cas4 contributes to CRISPR adaptation is lacking. Here, we biochemically reconstitute the CRISPR-Cas type I-D adaptation system and show two functionally distinct adaptation complexes: Cas4-Cas1 and Cas1-Cas2. The Cas4-Cas1 complex recognizes and cleaves protospacer adjacent motif (PAM) sequences in 3' overhangs in a sequence-specific manner, while the Cas1-Cas2 complex defines the cleavage of non-PAM sites via host-factor nucleases. Both sub-complexes are capable of mediating half-site integration, facilitating the integration of processed spacers in the correct interference-proficient orientation. We provide a model in which an asymmetric adaptation complex differentially acts on PAM- and non-PAM-containing overhangs, providing cues for the correct orientation of spacer integration.
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Affiliation(s)
- Sebastian N Kieper
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands
| | - Cristóbal Almendros
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands
| | - Anna C Haagsma
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands
| | - Arjan Barendregt
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands; and Utrecht, Netherlands.,Netherlands Proteomics Center, Utrecht, Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands; and Utrecht, Netherlands.,Netherlands Proteomics Center, Utrecht, Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands; Utrecht, Netherlands
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Taylor HN, Laderman E, Armbrust M, Hallmark T, Keiser D, Bondy-Denomy J, Jackson RN. Positioning Diverse Type IV Structures and Functions Within Class 1 CRISPR-Cas Systems. Front Microbiol 2021; 12:671522. [PMID: 34093491 PMCID: PMC8175902 DOI: 10.3389/fmicb.2021.671522] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/26/2021] [Indexed: 12/26/2022] Open
Abstract
Type IV CRISPR systems encode CRISPR associated (Cas)-like proteins that combine with small RNAs to form multi-subunit ribonucleoprotein complexes. However, the lack of Cas nucleases, integrases, and other genetic features commonly observed in most CRISPR systems has made it difficult to predict type IV mechanisms of action and biological function. Here we summarize recent bioinformatic and experimental advancements that collectively provide the first glimpses into the function of specific type IV subtypes. We also provide a bioinformatic and structural analysis of type IV-specific proteins within the context of multi-subunit (class 1) CRISPR systems, informing future studies aimed at elucidating the function of these cryptic systems.
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Affiliation(s)
- Hannah N. Taylor
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Eric Laderman
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, United States
| | - Matt Armbrust
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Thomson Hallmark
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Dylan Keiser
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, United States
| | - Ryan N. Jackson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
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36
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Riediger M, Spät P, Bilger R, Voigt K, Maček B, Hess WR. Analysis of a photosynthetic cyanobacterium rich in internal membrane systems via gradient profiling by sequencing (Grad-seq). THE PLANT CELL 2021; 33:248-269. [PMID: 33793824 PMCID: PMC8136920 DOI: 10.1093/plcell/koaa017] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/12/2020] [Indexed: 05/23/2023]
Abstract
Although regulatory small RNAs have been reported in photosynthetic cyanobacteria, the lack of clear RNA chaperones involved in their regulation poses a conundrum. Here, we analyzed the full complement of cellular RNAs and proteins using gradient profiling by sequencing (Grad-seq) in Synechocystis 6803. Complexes with overlapping subunits such as the CpcG1-type versus the CpcL-type phycobilisomes or the PsaK1 versus PsaK2 photosystem I pre(complexes) could be distinguished, supporting the high quality of this approach. Clustering of the in-gradient distribution profiles followed by several additional criteria yielded a short list of potential RNA chaperones that include an YlxR homolog and a cyanobacterial homolog of the KhpA/B complex. The data suggest previously undetected complexes between accessory proteins and CRISPR-Cas systems, such as a Csx1-Csm6 ribonucleolytic defense complex. Moreover, the exclusive association of either RpoZ or 6S RNA with the core RNA polymerase complex and the existence of a reservoir of inactive sigma-antisigma complexes is suggested. The Synechocystis Grad-seq resource is available online at https://sunshine.biologie.uni-freiburg.de/GradSeqExplorer/ providing a comprehensive resource for the functional assignment of RNA-protein complexes and multisubunit protein complexes in a photosynthetic organism.
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Affiliation(s)
- Matthias Riediger
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Philipp Spät
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Raphael Bilger
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Karsten Voigt
- IT Administration, Institute of Biology 3, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Boris Maček
- Department of Quantitative Proteomics, Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
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Abstract
CRISPR-Cas systems are immune systems that protect bacteria and archaea against their viruses, bacteriophages. Immunity is achieved through the acquisition of short DNA fragments from the viral invader’s genome. CRISPR-Cas immune systems adapt to new threats by acquiring new spacers from invading nucleic acids such as phage genomes. However, some CRISPR-Cas loci lack genes necessary for spacer acquisition despite variation in spacer content between microbial strains. It has been suggested that such loci may use acquisition machinery from cooccurring CRISPR-Cas systems within the same strain. Here, following infection by a virulent phage with a double-stranded DNA (dsDNA) genome, we observed spacer acquisition in the native host Flavobacterium columnare that carries an acquisition-deficient CRISPR-Cas subtype VI-B system and a complete subtype II-C system. We show that the VI-B locus acquires spacers from both the bacterial and phage genomes, while the newly acquired II-C spacers mainly target the viral genome. Both loci preferably target the terminal end of the phage genome, with priming-like patterns around a preexisting II-C protospacer. Through gene deletion, we show that the RNA-cleaving VI-B system acquires spacers in trans using acquisition machinery from the DNA-cleaving II-C system. Our observations support the concept of cross talk between CRISPR-Cas systems and raise further questions regarding the plasticity of adaptation modules.
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38
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Wu C, Tang D, Cheng J, Hu D, Yang Z, Ma X, He H, Yao S, Fu TM, Yu Y, Chen Q. Mechanisms of spacer acquisition by sequential assembly of the adaptation module in Synechocystis. Nucleic Acids Res 2021; 49:2973-2984. [PMID: 33619565 PMCID: PMC7969031 DOI: 10.1093/nar/gkab105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 02/05/2023] Open
Abstract
CRISPR–Cas immune systems process and integrate short fragments of DNA from new invaders as spacers into the host CRISPR locus to establish molecular memory of prior infection, which is also known as adaptation in the field. Some CRISPR–Cas systems rely on Cas1 and Cas2 to complete the adaptation process, which has been characterized in a few systems. In contrast, many other CRISPR–Cas systems require an additional factor of Cas4 for efficient adaptation, the mechanism of which remains less understood. Here we present biochemical reconstitution of the Synechocystis sp. PCC6803 type I-D adaptation system, X-ray crystal structures of Cas1–Cas2–prespacer complexes, and negative stained electron microscopy structure of the Cas4–Cas1 complex. Cas4 and Cas2 compete with each other to interact with Cas1. In the absence of prespacer, Cas4 but not Cas2 assembles with Cas1 into a very stable complex for processing the prespacer. Strikingly, the Cas1-prespacer complex develops a higher binding affinity toward Cas2 to form the Cas1–Cas2–prespacer ternary complex for integration. Together, we show a two-step sequential assembly mechanism for the type I-D adaptation module of Synechocystis, in which Cas4–Cas1 and Cas1–Cas2 function as two exclusive complexes for prespacer processing, capture, and integration.
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Affiliation(s)
- Chengyong Wu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Dongmei Tang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Jie Cheng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Daojun Hu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Zejing Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Xue Ma
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Haihuai He
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Shaohua Yao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Tian-Min Fu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA.,The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
| | - Yamei Yu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
| | - Qiang Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P.R. China
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Görücü Yilmaz S. Genome editing technologies: CRISPR, LEAPER, RESTORE, ARCUT, SATI, and RESCUE. EXCLI JOURNAL 2021; 20:19-45. [PMID: 33510590 PMCID: PMC7838830 DOI: 10.17179/excli2020-3070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/10/2020] [Indexed: 12/16/2022]
Abstract
Genome editing technologies include techniques used for desired genetic modifications and allow the insertion, modification or deletion of specific DNA fragments. Recent advances in genome biology offer unprecedented promise for interdisciplinary collaboration and applications in gene editing. New genome editing technologies enable specific and efficient genome modifications. The sources that inspire these modifications and already exist in the genome are DNA degradation enzymes and DNA repair pathways. Six of these recent technologies are the clustered regularly interspaced short palindromic repeats (CRISPR), leveraging endogenous ADAR for programmable editing of RNA (LEAPER), recruiting endogenous ADAR to specific transcripts for oligonucleotide-mediated RNA editing (RESTORE), chemistry-based artificial restriction DNA cutter (ARCUT), single homology arm donor mediated intron-targeting integration (SATI), RNA editing for specific C-to-U exchange (RESCUE). These technologies are widely used from various biomedical researches to clinics, agriculture, and allow you to rearrange genomic sequences, create cell lines and animal models to solve human diseases. This review emphasizes the characteristics, superiority, limitations, also whether each technology can be used in different biological systems and the potential application of these systems in the treatment of several human diseases.
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Affiliation(s)
- Senay Görücü Yilmaz
- Department of Nutrition and Dietetics, Gaziantep University, Gaziantep, Turkey 27310
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40
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Zink IA, Wimmer E, Schleper C. Heavily Armed Ancestors: CRISPR Immunity and Applications in Archaea with a Comparative Analysis of CRISPR Types in Sulfolobales. Biomolecules 2020; 10:E1523. [PMID: 33172134 PMCID: PMC7694759 DOI: 10.3390/biom10111523] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Prokaryotes are constantly coping with attacks by viruses in their natural environments and therefore have evolved an impressive array of defense systems. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is an adaptive immune system found in the majority of archaea and about half of bacteria which stores pieces of infecting viral DNA as spacers in genomic CRISPR arrays to reuse them for specific virus destruction upon a second wave of infection. In detail, small CRISPR RNAs (crRNAs) are transcribed from CRISPR arrays and incorporated into type-specific CRISPR effector complexes which further degrade foreign nucleic acids complementary to the crRNA. This review gives an overview of CRISPR immunity to newcomers in the field and an update on CRISPR literature in archaea by comparing the functional mechanisms and abundances of the diverse CRISPR types. A bigger fraction is dedicated to the versatile and prevalent CRISPR type III systems, as tremendous progress has been made recently using archaeal models in discerning the controlled molecular mechanisms of their unique tripartite mode of action including RNA interference, DNA interference and the unique cyclic-oligoadenylate signaling that induces promiscuous RNA shredding by CARF-domain ribonucleases. The second half of the review spotlights CRISPR in archaea outlining seminal in vivo and in vitro studies in model organisms of the euryarchaeal and crenarchaeal phyla, including the application of CRISPR-Cas for genome editing and gene silencing. In the last section, a special focus is laid on members of the crenarchaeal hyperthermophilic order Sulfolobales by presenting a thorough comparative analysis about the distribution and abundance of CRISPR-Cas systems, including arrays and spacers as well as CRISPR-accessory proteins in all 53 genomes available to date. Interestingly, we find that CRISPR type III and the DNA-degrading CRISPR type I complexes co-exist in more than two thirds of these genomes. Furthermore, we identified ring nuclease candidates in all but two genomes and found that they generally co-exist with the above-mentioned CARF domain ribonucleases Csx1/Csm6. These observations, together with published literature allowed us to draft a working model of how CRISPR-Cas systems and accessory proteins cross talk to establish native CRISPR anti-virus immunity in a Sulfolobales cell.
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41
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It is unclear how important CRISPR-Cas systems are for protecting natural populations of bacteria against infections by mobile genetic elements. Proc Natl Acad Sci U S A 2020; 117:27777-27785. [PMID: 33122438 PMCID: PMC7668106 DOI: 10.1073/pnas.1915966117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Articles on CRISPR commonly open with some variant of the phrase “these short palindromic repeats and their associated endonucleases (Cas) are an adaptive immune system that exists to protect bacteria and archaea from viruses and infections with other mobile genetic elements.” There is an abundance of genomic data consistent with the hypothesis that CRISPR plays this role in natural populations of bacteria and archaea, and experimental demonstrations with a few species of bacteria and their phage and plasmids show that CRISPR-Cas systems can play this role in vitro. Not at all clear are the ubiquity, magnitude, and nature of the contribution of CRISPR-Cas systems to the ecology and evolution of natural populations of microbes and the strength of selection mediated by different types of phage and plasmids to the evolution and maintenance of CRISPR-Cas systems. In this perspective, with the aid of heuristic mathematical–computer simulation models, we explore the a priori conditions under which exposure to lytic and temperate phage and conjugative plasmids will select for and maintain CRISPR-Cas systems in populations of bacteria and archaea. We review the existing literature addressing these ecological and evolutionary questions and highlight the experimental and other evidence needed to fully understand the conditions responsible for the evolution and maintenance of CRISPR-Cas systems and the contribution of these systems to the ecology and evolution of bacteria, archaea, and the mobile genetic elements that infect them.
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42
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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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43
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Ye Q, Zhao X, Liu J, Zeng Z, Zhang Z, Liu T, Li Y, Han W, Peng N. CRISPR-Associated Factor Csa3b Regulates CRISPR Adaptation and Cmr-Mediated RNA Interference in Sulfolobus islandicus. Front Microbiol 2020; 11:2038. [PMID: 32983033 PMCID: PMC7480081 DOI: 10.3389/fmicb.2020.02038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022] Open
Abstract
Acquisition of spacers confers the CRISPR–Cas system with the memory to defend against invading mobile genetic elements. We previously reported that the CRISPR-associated factor Csa3a triggers CRISPR adaptation in Sulfolobus islandicus. However, a feedback regulation of CRISPR adaptation remains unclear. Here we show that another CRISPR-associated factor, Csa3b, binds a cyclic oligoadenylate (cOA) analog (5′-CAAAA-3′) and mutation at its CARF domain, which reduces the binding affinity. Csa3b also binds the promoter of adaptation cas genes, and the cOA analog enhances their binding probably by allosteric regulation. Deletion of the csa3b gene triggers spacer acquisition from both plasmid and viral DNAs, indicating that Csa3b acted as a repressor for CRISPR adaptation. Moreover, we also find that Csa3b activates the expression of subtype cmr-α and cmr-β genes according to transcriptome data and demonstrate that Csa3b binds the promoters of cmr genes. The deletion of the csa3b gene reduces Cmr-mediated RNA interference activity, indicating that Csa3b acts as a transcriptional activator for Cmr-mediated RNA interference. In summary, our findings reveal a novel pathway for the regulation of CRISPR adaptation and CRISPR–Cmr RNA interference in S. islandicus. Our results also suggest a feedback repression of CRIPSR adaptation by the Csa3b factor and the cOA signal produced by the Cmr complex at the CRISPR interference stage.
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Affiliation(s)
- Qing Ye
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xueqiao Zhao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jilin Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhifeng Zeng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhufeng Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Tao Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yingjun Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wenyuan Han
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Nan Peng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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44
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Van Orden MJ, Newsom S, Rajan R. CRISPR type II-A subgroups exhibit phylogenetically distinct mechanisms for prespacer insertion. J Biol Chem 2020; 295:10956-10968. [PMID: 32513871 DOI: 10.1074/jbc.ra120.013554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/04/2020] [Indexed: 12/20/2022] Open
Abstract
CRISPR-Cas is an adaptive immune system that protects prokaryotes against foreign nucleic acids. Prokaryotes gain immunity by acquiring short pieces of the invading nucleic acid termed prespacers and inserting them into their CRISPR array. In type II-A systems, Cas1 and Cas2 proteins insert prespacers always at the leader-repeat junction of the CRISPR array. Among type II-A CRISPR systems, three distinct groups (G1, G2, and G3) exist according to the extent of DNA sequence conservation at the 3' end of the leader. However, the mechanisms by which these conserved motifs interact with their cognate Cas1 and Cas2 proteins remain unclear. Here, we performed in vitro integration assays, finding that for G1 and G2, the insertion site is recognized through defined mechanisms, at least in members examined to date, whereas G3 exhibits no sequence-specific insertion. G1 first recognized a 12-bp sequence at the leader-repeat junction and performed leader-side insertion before proceeding to spacer-side insertion. G2 recognized the full repeat sequence and could perform independent leader-side or spacer-side insertions, although the leader-side insertion was faster than spacer-side. The prespacer morphology requirements for Cas1-Cas2 varied, with G1 stringently requiring a 5-nucleotide 3' overhang and G2 being able to insert many forms of prespacers with variable efficiencies. These results highlight the intricacy of protein-DNA sequence interactions within the seemingly similar type II-A integration complexes and provide mechanistic insights into prespacer insertion. These interactions can be fine-tuned to expand the Cas1-Cas2 toolset for inserting small DNAs into diverse DNA targets.
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Affiliation(s)
- Mason J Van Orden
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Sydney Newsom
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
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45
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Sasnauskas G, Siksnys V. CRISPR adaptation from a structural perspective. Curr Opin Struct Biol 2020; 65:17-25. [PMID: 32570107 DOI: 10.1016/j.sbi.2020.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
Bacterial CRISPR-Cas systems provide adaptive immunity against viruses and other mobile genome elements. During the adaptation step cells become immunized by insertion of short fragments of foreign DNA, termed spacers, into the genomic region called a CRISPR array. Selection, processing and insertion of new spacers is an elaborate and precisely orchestrated reaction, which relies on the Cas1-Cas2 integrase complex and accessory proteins that vary among different types of CRISPR-Cas systems. This review focuses on CRISPR adaptation from the structural perspective, with the spotlight on adaptation proteins employed by type I and type II CRISPR-Cas systems.
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Affiliation(s)
- Giedrius Sasnauskas
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania.
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46
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Abstract
CRISPR research began over 30 years ago with the incidental discovery of an unusual nucleotide arrangement in the Escherichia coli genome. It took 20 years to find the main function of CRISPR-Cas systems as an adaptive defence mechanism against invading nucleic acids, and our knowledge of their biology has steadily increased ever since. In parallel, the number of applications derived from CRISPR-Cas systems has risen spectacularly. The CRISPR-based genome editing tool is arguably the most exciting application in both basic and applied research. Lately, CRISPR-Cas research has partially shifted to the least understood aspect of its biology: the ability of CRISPR-Cas systems to acquire new immunities during the so-called adaptation step. To date, the most efficient natural system to readily acquire new spacers is the type II-A system of the gram-positive dairy bacterium Streptococcus thermophilus. The discovery of additional systems able to acquire new spacers will hopefully draw more attention to this step of CRISPR-Cas biology. This review focuses on the breakthroughs that have helped to unravel the adaptation phase and on questions that remain to be answered.
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Affiliation(s)
- Cas Mosterd
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
| | - Geneviève M Rousseau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
| | - Sylvain Moineau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada.,Félix d'Hérelle Reference Center for Bacterial Viruses, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
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47
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Kieper SN, Almendros C, Brouns SJJ. Conserved motifs in the CRISPR leader sequence control spacer acquisition levels in Type I-D CRISPR-Cas systems. FEMS Microbiol Lett 2020; 366:5525085. [PMID: 31252430 PMCID: PMC6607411 DOI: 10.1093/femsle/fnz129] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
Integrating short DNA fragments at the correct leader-repeat junction is key to successful CRISPR-Cas memory formation. The Cas1-2 proteins are responsible to carry out this process. However, the CRISPR adaptation process additionally requires a DNA element adjacent to the CRISPR array, called leader, to facilitate efficient localization of the correct integration site. In this work, we introduced the core CRISPR adaptation genes cas1 and cas2 from the Type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and assessed spacer integration efficiency. Truncation of the leader resulted in a significant reduction of spacer acquisition levels and revealed the importance of different conserved regions for CRISPR adaptation rates. We found three conserved sequence motifs in the leader of I-D CRISPR arrays that each affected spacer acquisition rates, including an integrase anchoring site. Our findings support the model in which the leader sequence is an integral part of type I-D adaptation in Synechocystis sp. acting as a localization signal for the adaptation complex to drive CRISPR adaptation at the first repeat of the CRISPR array.
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Affiliation(s)
- Sebastian N Kieper
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Cristóbal Almendros
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Stan J J Brouns
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.,Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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48
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Real-time observation of CRISPR spacer acquisition by Cas1-Cas2 integrase. Nat Struct Mol Biol 2020; 27:489-499. [PMID: 32367067 PMCID: PMC7241818 DOI: 10.1038/s41594-020-0415-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/16/2020] [Indexed: 01/13/2023]
Abstract
Cas1 integrase associates with Cas2 to insert short DNA fragments into a CRISPR array, establishing nucleic acid memory in prokaryotes. Here we applied single-molecule FRET methods to the Enterococcus faecalis (Efa) Cas1–Cas2 system to establish a kinetic framework describing target-searching, integration, and post-synapsis events. EfaCas1–Cas2 on its own is not able to find the CRISPR repeat in the CRISPR array; it only does so after prespacer loading. The leader sequence adjacent to the repeat further stabilizes EfaCas1–Cas2 contacts, enabling leader-side integration and subsequent spacer-side integration. The resulting post-synaptic complex has a surprisingly short mean lifetime. Remarkably, transcription efficiently resolves the postsynaptic complex and we predict that this is a conserved mechanism that ensures efficient and directional spacer integration in many CRISPR systems. Overall, our study provides a complete model of spacer acquisition, which can be harnessed for DNA-based information storage and cell lineage tracing technologies.
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49
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Dhingra Y, Sashital DG. Updating the CRISPR Catalogue. CRISPR J 2020; 3:78-80. [PMID: 32315221 DOI: 10.1089/crispr.2020.29088.ydh] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Yukti Dhingra
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Dipali G Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, USA
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50
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Detection of CRISPR adaptation. Biochem Soc Trans 2020; 48:257-269. [PMID: 32010936 PMCID: PMC7054753 DOI: 10.1042/bst20190662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/26/2019] [Accepted: 01/03/2020] [Indexed: 12/12/2022]
Abstract
Prokaryotic adaptive immunity is built when short DNA fragments called spacers are acquired into CRISPR (clustered regularly interspaced short palindromic repeats) arrays. CRISPR adaptation is a multistep process which comprises selection, generation, and incorporation of prespacers into arrays. Once adapted, spacers provide immunity through the recognition of complementary nucleic acid sequences, channeling them for destruction. To prevent deleterious autoimmunity, CRISPR adaptation must therefore be a highly regulated and infrequent process, at least in the absence of genetic invaders. Over the years, ingenious methods to study CRISPR adaptation have been developed. In this paper, we discuss and compare methods that detect CRISPR adaptation and its intermediates in vivo and propose suppressing PCR as a simple modification of a popular assay to monitor spacer acquisition with increased sensitivity.
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