1
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Wiegand T, Hoffmann FT, Walker MWG, Tang S, Richard E, Le HC, Meers C, Sternberg SH. TnpB homologues exapted from transposons are RNA-guided transcription factors. Nature 2024:10.1038/s41586-024-07598-4. [PMID: 38926585 DOI: 10.1038/s41586-024-07598-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 05/23/2024] [Indexed: 06/28/2024]
Abstract
Transposon-encoded tnpB and iscB genes encode RNA-guided DNA nucleases that promote their own selfish spread through targeted DNA cleavage and homologous recombination1-4. These widespread gene families were repeatedly domesticated over evolutionary timescales, leading to the emergence of diverse CRISPR-associated nucleases including Cas9 and Cas12 (refs. 5,6). We set out to test the hypothesis that TnpB nucleases may have also been repurposed for novel, unexpected functions other than CRISPR-Cas adaptive immunity. Here, using phylogenetics, structural predictions, comparative genomics and functional assays, we uncover multiple independent genesis events of programmable transcription factors, which we name TnpB-like nuclease-dead repressors (TldRs). These proteins use naturally occurring guide RNAs to specifically target conserved promoter regions of the genome, leading to potent gene repression in a mechanism akin to CRISPR interference technologies invented by humans7. Focusing on a TldR clade found broadly in Enterobacteriaceae, we discover that bacteriophages exploit the combined action of TldR and an adjacently encoded phage gene to alter the expression and composition of the host flagellar assembly, a transformation with the potential to impact motility8, phage susceptibility9, and host immunity10. Collectively, this work showcases the diverse molecular innovations that were enabled through repeated exaptation of transposon-encoded genes, and reveals the evolutionary trajectory of diverse RNA-guided transcription factors.
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Affiliation(s)
- Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Florian T Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Matt W G Walker
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Egill Richard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Hoang C Le
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
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2
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Ganguly C, Rostami S, Long K, Aribam SD, Rajan R. Unity among the diverse RNA-guided CRISPR-Cas interference mechanisms. J Biol Chem 2024; 300:107295. [PMID: 38641067 PMCID: PMC11127173 DOI: 10.1016/j.jbc.2024.107295] [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: 06/24/2023] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 04/21/2024] Open
Abstract
CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated) systems are adaptive immune systems that protect bacteria and archaea from invading mobile genetic elements (MGEs). The Cas protein-CRISPR RNA (crRNA) complex uses complementarity of the crRNA "guide" region to specifically recognize the invader genome. CRISPR effectors that perform targeted destruction of the foreign genome have emerged independently as multi-subunit protein complexes (Class 1 systems) and as single multi-domain proteins (Class 2). These different CRISPR-Cas systems can cleave RNA, DNA, and protein in an RNA-guided manner to eliminate the invader, and in some cases, they initiate programmed cell death/dormancy. The versatile mechanisms of the different CRISPR-Cas systems to target and destroy nucleic acids have been adapted to develop various programmable-RNA-guided tools and have revolutionized the development of fast, accurate, and accessible genomic applications. In this review, we present the structure and interference mechanisms of different CRISPR-Cas systems and an analysis of their unified features. The three types of Class 1 systems (I, III, and IV) have a conserved right-handed helical filamentous structure that provides a backbone for sequence-specific targeting while using unique proteins with distinct mechanisms to destroy the invader. Similarly, all three Class 2 types (II, V, and VI) have a bilobed architecture that binds the RNA-DNA/RNA hybrid and uses different nuclease domains to cleave invading MGEs. Additionally, we highlight the mechanistic similarities of CRISPR-Cas enzymes with other RNA-cleaving enzymes and briefly present the evolutionary routes of the different CRISPR-Cas systems.
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Affiliation(s)
- Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Saadi Rostami
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Kole Long
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Swarmistha Devi Aribam
- 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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3
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Yeh HY, Cox NA, Hinton A, Berrang ME. Detection and Distribution of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) in Campylobacter jejuni Isolates from Chicken Livers. J Food Prot 2024; 87:100250. [PMID: 38382707 DOI: 10.1016/j.jfp.2024.100250] [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: 08/23/2022] [Revised: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
Campylobacter jejuni is the leading foodborne bacterial pathogen that causes human gastroenteritis worldwide linked to the consumption of undercooked broiler livers. Application of bacteriophages during poultry production has been used as an alternative approach to reduce contamination of poultry meat by Campylobacter. To make this approach effective, understanding the presence of the bacteriophage sequences in the CRISPR spacers in C. jejuni is critical as they may confer bacterial resistance to bacteriophage treatment. Therefore, in this study, we explored the distribution of the CRISPR arrays from 178 C. jejuni isolated from chicken livers between January and July 2018. Genomic DNA of C. jejuni isolates was extracted, and CRISPR type 1 sequences were amplified by PCR. Amplicons were purified and sequenced by the Sanger dideoxy sequencing method. Direct repeats (DRs) and spacers of CRISPR sequences were identified using the CRISPRFinder program. Further, spacer sequences were submitted to the CRISPRTarget to identify potential homology to bacteriophage types. Even though CRISPR-Cas is reportedly not an active system in Campylobacter, a total of 155 (87%) C. jejuni isolates were found to harbor CRISPR sequences; one type of DR was identified in all 155 isolates. The CRISPR loci lengths ranged from 97 to 431 nucleotides. The numbers of spacers ranged from one to six. A total of 371 spacer sequences were identified in the 155 isolates that could be grouped into 51 distinctive individual sequences. Further comparison of these 51 spacer sequences with those in databases showed that most spacer sequences were homologous to Campylobacter bacteriophage DA10. The results of our study provide important information relative to the development of an effective bacteriophage treatment to mitigate Campylobacter during poultry production.
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Affiliation(s)
- Hung-Yueh Yeh
- U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, 950 College Station Road, Athens, GA 30605-2720, USA.
| | - Nelson A Cox
- U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, 950 College Station Road, Athens, GA 30605-2720, USA
| | - Arthur Hinton
- U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, 950 College Station Road, Athens, GA 30605-2720, USA
| | - Mark E Berrang
- U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, 950 College Station Road, Athens, GA 30605-2720, USA
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4
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Wimmer F, Englert F, Wandera KG, Alkhnbashi O, Collins S, Backofen R, Beisel C. Interrogating two extensively self-targeting Type I CRISPR-Cas systems in Xanthomonas albilineans reveals distinct anti-CRISPR proteins that block DNA degradation. Nucleic Acids Res 2024; 52:769-783. [PMID: 38015466 PMCID: PMC10810201 DOI: 10.1093/nar/gkad1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023] Open
Abstract
CRISPR-Cas systems store fragments of invader DNA as spacers to recognize and clear those same invaders in the future. Spacers can also be acquired from the host's genomic DNA, leading to lethal self-targeting. While self-targeting can be circumvented through different mechanisms, natural examples remain poorly explored. Here, we investigate extensive self-targeting by two CRISPR-Cas systems encoding 24 self-targeting spacers in the plant pathogen Xanthomonas albilineans. We show that the native I-C and I-F1 systems are actively expressed and that CRISPR RNAs are properly processed. When expressed in Escherichia coli, each Cascade complex binds its PAM-flanked DNA target to block transcription, while the addition of Cas3 paired with genome targeting induces cell killing. While exploring how X. albilineans survives self-targeting, we predicted putative anti-CRISPR proteins (Acrs) encoded within the bacterium's genome. Screening of identified candidates with cell-free transcription-translation systems and in E. coli revealed two Acrs, which we named AcrIC11 and AcrIF12Xal, that inhibit the activity of Cas3 but not Cascade of the respective system. While AcrF12Xal is homologous to AcrIF12, AcrIC11 shares sequence and structural homology with the anti-restriction protein KlcA. These findings help explain tolerance of self-targeting through two CRISPR-Cas systems and expand the known suite of DNA degradation-inhibiting Acrs.
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Affiliation(s)
- Franziska Wimmer
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Frank Englert
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Katharina G Wandera
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Omer S Alkhnbashi
- Information and Computer Science Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Intelligent Secure Systems (IRC-ISS), King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
| | - Scott P Collins
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
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5
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Wiegand T, Hoffmann FT, Walker MWG, Tang S, Richard E, Le HC, Meers C, Sternberg SH. Emergence of RNA-guided transcription factors via domestication of transposon-encoded TnpB nucleases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569447. [PMID: 38076855 PMCID: PMC10705468 DOI: 10.1101/2023.11.30.569447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Transposon-encoded tnpB genes encode RNA-guided DNA nucleases that promote their own selfish spread through targeted DNA cleavage and homologous recombination1-4. This widespread gene family was repeatedly domesticated over evolutionary timescales, leading to the emergence of diverse CRISPR-associated nucleases including Cas9 and Cas125,6. We set out to test the hypothesis that TnpB nucleases may have also been repurposed for novel, unexpected functions other than CRISPR-Cas. Here, using phylogenetics, structural predictions, comparative genomics, and functional assays, we uncover multiple instances of programmable transcription factors that we name TnpB-like nuclease-dead repressors (TldR). These proteins employ naturally occurring guide RNAs to specifically target conserved promoter regions of the genome, leading to potent gene repression in a mechanism akin to CRISPRi technologies invented by humans7. Focusing on a TldR clade found broadly in Enterobacteriaceae, we discover that bacteriophages exploit the combined action of TldR and an adjacently encoded phage gene to alter the expression and composition of the host flagellar assembly, a transformation with the potential to impact motility8, phage susceptibility9, and host immunity10. Collectively, this work showcases the diverse molecular innovations that were enabled through repeated exaptation of genes encoded by transposable elements, and reveals that RNA-guided transcription factors emerged long before the development of dCas9-based editors.
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Affiliation(s)
- Tanner Wiegand
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Florian T Hoffmann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Matt W G Walker
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stephen Tang
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Egill Richard
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Hoang C Le
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Chance Meers
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
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6
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Liu C, Wang R, Li J, Cheng F, Shu X, Zhao H, Xue Q, Yu H, Wu A, Wang L, Hu S, Zhang Y, Yang J, Xiang H, Li M. Widespread RNA-based cas regulation monitors crRNA abundance and anti-CRISPR proteins. Cell Host Microbe 2023; 31:1481-1493.e6. [PMID: 37659410 DOI: 10.1016/j.chom.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/04/2023] [Accepted: 08/09/2023] [Indexed: 09/04/2023]
Abstract
CRISPR RNAs (crRNAs) and Cas proteins work together to provide prokaryotes with adaptive immunity against genetic invaders like bacteriophages and plasmids. However, the coordination of crRNA production and cas expression remains poorly understood. Here, we demonstrate that widespread modulatory mini-CRISPRs encode cas-regulating RNAs (CreRs) that mediate autorepression of type I-B, I-E, and V-A Cas proteins, based on their limited complementarity to cas promoters. This autorepression not only reduces autoimmune risks but also responds to changes in the abundance of canonical crRNAs that compete with CreR for Cas proteins. Furthermore, the CreR-guided autorepression of Cas proteins can be alleviated or even subverted by diverse bacteriophage anti-CRISPR (Acr) proteins that inhibit Cas effectors, which, in turn, promotes the generation of new Cas proteins. Our findings reveal a general RNA-guided autorepression paradigm for diverse Cas effectors, shedding light on the intricate self-coordination of CRISPR-Cas and its transcriptional counterstrategy against Acr proteins.
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Affiliation(s)
- Chao Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Rui Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jie Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Feiyue Cheng
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xian Shu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Huiwei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiong Xue
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Aici Wu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Lingyun Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Plant Protection, Shandong Agricultural University, Taian, Shandong, China
| | - Sushu Hu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yihan Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; School of Life Sciences, Hebei University, Baoding, Hebei, China
| | - Jun Yang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China.
| | - Ming Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; College of Life Science, University of Chinese Academy of Sciences, Beijing, China.
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7
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Ham DT, Browne TS, Banglorewala PN, Wilson TL, Michael RK, Gloor GB, Edgell DR. A generalizable Cas9/sgRNA prediction model using machine transfer learning with small high-quality datasets. Nat Commun 2023; 14:5514. [PMID: 37679324 PMCID: PMC10485023 DOI: 10.1038/s41467-023-41143-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
The CRISPR/Cas9 nuclease from Streptococcus pyogenes (SpCas9) can be used with single guide RNAs (sgRNAs) as a sequence-specific antimicrobial agent and as a genome-engineering tool. However, current bacterial sgRNA activity models struggle with accurate predictions and do not generalize well, possibly because the underlying datasets used to train the models do not accurately measure SpCas9/sgRNA activity and cannot distinguish on-target cleavage from toxicity. Here, we solve this problem by using a two-plasmid positive selection system to generate high-quality data that more accurately reports on SpCas9/sgRNA cleavage and that separates activity from toxicity. We develop a machine learning architecture (crisprHAL) that can be trained on existing datasets, that shows marked improvements in sgRNA activity prediction accuracy when transfer learning is used with small amounts of high-quality data, and that can generalize predictions to different bacteria. The crisprHAL model recapitulates known SpCas9/sgRNA-target DNA interactions and provides a pathway to a generalizable sgRNA bacterial activity prediction tool that will enable accurate antimicrobial and genome engineering applications.
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Affiliation(s)
- Dalton T Ham
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | - Tyler S Browne
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | - Pooja N Banglorewala
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | | | | | - Gregory B Gloor
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada.
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada.
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8
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Shmakov SA, Barth ZK, Makarova KS, Wolf Y, Brover V, Peters J, Koonin E. Widespread CRISPR-derived RNA regulatory elements in CRISPR-Cas systems. Nucleic Acids Res 2023; 51:8150-8168. [PMID: 37283088 PMCID: PMC10450183 DOI: 10.1093/nar/gkad495] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/15/2023] [Accepted: 05/25/2023] [Indexed: 06/08/2023] Open
Abstract
CRISPR-cas loci typically contain CRISPR arrays with unique spacers separating direct repeats. Spacers along with portions of adjacent repeats are transcribed and processed into CRISPR(cr) RNAs that target complementary sequences (protospacers) in mobile genetic elements, resulting in cleavage of the target DNA or RNA. Additional, standalone repeats in some CRISPR-cas loci produce distinct cr-like RNAs implicated in regulatory or other functions. We developed a computational pipeline to systematically predict crRNA-like elements by scanning for standalone repeat sequences that are conserved in closely related CRISPR-cas loci. Numerous crRNA-like elements were detected in diverse CRISPR-Cas systems, mostly, of type I, but also subtype V-A. Standalone repeats often form mini-arrays containing two repeat-like sequence separated by a spacer that is partially complementary to promoter regions of cas genes, in particular cas8, or cargo genes located within CRISPR-Cas loci, such as toxins-antitoxins. We show experimentally that a mini-array from a type I-F1 CRISPR-Cas system functions as a regulatory guide. We also identified mini-arrays in bacteriophages that could abrogate CRISPR immunity by inhibiting effector expression. Thus, recruitment of CRISPR effectors for regulatory functions via spacers with partial complementarity to the target is a common feature of diverse CRISPR-Cas systems.
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Affiliation(s)
- Sergey A Shmakov
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Zachary K Barth
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Vyacheslav Brover
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Joseph E Peters
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
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9
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Bauer R, Haider D, Grempels A, Roscher R, Mauerer S, Spellerberg B. Diversity of CRISPR-Cas type II-A systems in Streptococcus anginosus. Front Microbiol 2023; 14:1188671. [PMID: 37396379 PMCID: PMC10310304 DOI: 10.3389/fmicb.2023.1188671] [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: 03/17/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Streptococcus anginosus is a commensal Streptococcal species that is often associated with invasive bacterial infections. However, little is known about its molecular genetic background. Many Streptococcal species, including S. anginosus, harbor clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems. A CRISPR-Cas type II-A system as well as a type II-C system have been reported for this species. To characterize the CRISPR-Cas type II systems of S. anginosus in more detail, we conducted a phylogenetic analysis of Cas9 sequences from CRISPR-Cas type II systems with a special focus on streptococci and S. anginosus. In addition, a phylogenetic analysis of S. anginosus strains based on housekeeping genes included in MLST analysis, was performed. All analyzed Cas9 sequences of S. anginosus clustered with the Cas9 sequences of CRISPR type II-A systems, including the Cas9 sequences of S. anginosus strains reported to harbor a type II-C system. The Cas9 genes of the CRISPR-Cas type II-C systems of other bacterial species separated into a different cluster. Moreover, analyzing the CRISPR loci found in S. anginosus, two distinct csn2 genes could be detected, a short form showing high similarity to the canonical form of the csn2 gene present in S. pyogenes. The second CRISPR type II locus of S. anginosus contained a longer variant of csn2 with close similarities to a csn2 gene that has previously been described in Streptococcus thermophilus. Since CRISPR-Cas type II-C systems do not contain a csn2 gene, the S. anginosus strains reported to have a CRISPR-Cas type II-C system appear to carry a variation of CRISPR-Cas type II-A harboring a long variant of csn2.
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10
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. Commun Biol 2023; 6:620. [PMID: 37296208 PMCID: PMC10256743 DOI: 10.1038/s42003-023-04994-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Group B Streptococcus (GBS; S. agalactiae) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δcas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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Affiliation(s)
| | - Gideon H Hillebrand
- University of Pittsburgh School of Medicine, Program in Microbiology and Immunology, Pittsburgh, PA, USA
| | - Venkata H Bhavana
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
| | - Jordan L Elder
- The Cleveland Clinic, Clinical Laboratory Services, Cleveland, OH, USA
| | - Adonis D'Mello
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas A Hooven
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA.
- Richard King Mellon Institute for Pediatric Research, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
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11
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.24.542094. [PMID: 37292749 PMCID: PMC10245859 DOI: 10.1101/2023.05.24.542094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Group B Streptococcus (GBS; S. agalactiae ) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δ cas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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12
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Shmakov SA, Barth ZK, Makarova KS, Wolf YI, Brover V, Peters JE, Koonin EV. Widespread CRISPR repeat-like RNA regulatory elements in CRISPR-Cas systems. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.03.530964. [PMID: 37090614 PMCID: PMC10120712 DOI: 10.1101/2023.03.03.530964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
CRISPR- cas loci typically contain CRISPR arrays with unique spacers separating direct repeats. Spacers along with portions of adjacent repeats are transcribed and processed into CRISPR(cr) RNAs that target complementary sequences (protospacers) in mobile genetic elements, resulting in cleavage of the target DNA or RNA. Additional, standalone repeats in some CRISPR- cas loci produce distinct cr-like RNAs implicated in regulatory or other functions. We developed a computational pipeline to systematically predict crRNA-like elements by scanning for standalone repeat sequences that are conserved in closely related CRISPR- cas loci. Numerous crRNA-like elements were detected in diverse CRISPR-Cas systems, mostly, of type I, but also subtype V-A. Standalone repeats often form mini-arrays containing two repeat-like sequence separated by a spacer that is partially complementary to promoter regions of cas genes, in particular cas8 , or cargo genes located within CRISPR-Cas loci, such as toxins-antitoxins. We show experimentally that a mini-array from a type I-F1 CRISPR-Cas system functions as a regulatory guide. We also identified mini-arrays in bacteriophages that could abrogate CRISPR immunity by inhibiting effector expression. Thus, recruitment of CRISPR effectors for regulatory functions via spacers with partial complementarity to the target is a common feature of diverse CRISPR-Cas systems.
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Affiliation(s)
- Sergey A. Shmakov
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Zachary K. Barth
- Department of Microbiology, Cornell University, Ithaca, NY 14853
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Yuri I. Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Vyacheslav Brover
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
| | - Joseph E. Peters
- Department of Microbiology, Cornell University, Ithaca, NY 14853
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
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13
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Nie M, Dong Y, Cao Q, Zhao D, Ji S, Huang H, Jiang M, Liu G, Liu Y. CRISPR Contributes to Adhesion, Invasion, and Biofilm Formation in Streptococcus agalactiae by Repressing Capsular Polysaccharide Production. Microbiol Spectr 2022; 10:e0211321. [PMID: 35861526 PMCID: PMC9430516 DOI: 10.1128/spectrum.02113-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 07/03/2022] [Indexed: 12/03/2022] Open
Abstract
The clustered regularly interspaced palindromic repeat (CRISPR)-associated (Cas) system functions classically as a prokaryotic defense system against invading mobile genetic elements, such as phages, plasmids, and viruses. Our previous study revealed that CRISPR deletion caused increased transcription of capsular polysaccharide (CPS) synthesis-related genes and severely attenuated virulence in the hypervirulent piscine Streptococcus agalactiae strain GD201008-001. Here, we found that CRISPR deficiency resulted in reduced adhesion, invasion, and biofilm formation abilities in this strain by upregulating the production of CPS. However, enhanced CPS production was not responsible for the attenuated phenotype of the ΔCRISPR mutant. RNA degradation assays indicated that inhibited transcription of the cps operon by CRISPR RNA (crRNA) was not due to the base pairing of the crRNA with the cps mRNA but to the repression of the promoter activity of cpsA, which is a putative transcriptional regulator of the capsule locus. IMPORTANCE Beyond protection from invading nucleic acids, CRISPR-Cas systems have been shown to have an important role in regulating bacterial endogenous genes. In this study, we demonstrate that crRNA inhibits the transcription of the cps operon by repressing the activity of promoter PcpsA, leading to increases in the abilities of adhesion, invasion, and biofilm formation in S. agalactiae. This study highlights the regulatory role of crRNA in bacterial physiology and provides a new explanation for the mechanism of crRNA-mediated endogenous gene regulation in S. agalactiae.
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Affiliation(s)
- Meng Nie
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Qing Cao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Dan Zhao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Shuting Ji
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Hao Huang
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Mingguo Jiang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Guangjin Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
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14
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Cheng F, Wu A, Liu C, Cao X, Wang R, Shu X, Wang L, Zhang Y, Xiang H, Li M. The toxin-antitoxin RNA guards of CRISPR-Cas evolved high specificity through repeat degeneration. Nucleic Acids Res 2022; 50:9442-9452. [PMID: 36018812 PMCID: PMC9458426 DOI: 10.1093/nar/gkac712] [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] [Received: 06/28/2022] [Revised: 07/30/2022] [Accepted: 08/10/2022] [Indexed: 12/24/2022] Open
Abstract
Recent discovery of ectopic repeats (outside CRISPR arrays) provided unprecedented insights into the nondefense roles of CRISPR-Cas. A striking example is the addiction module CreTA (CRISPR-regulated toxin-antitoxins), where one or two (in most cases) ectopic repeats produce CRISPR-resembling antitoxic (CreA) RNAs that direct the CRISPR effector Cascade to transcriptionally repress a toxic RNA (CreT). Here, we demonstrated that CreTA repeats are extensively degenerated in sequence, with the first repeat (ψR1) being more diverged than the second one (ψR2). As a result, such addiction modules become highly specific to their physically-linked CRISPR-Cas loci, and in most cases, CreA could not harness a heterologous CRISPR-Cas to suppress its cognate toxin. We further disclosed that this specificity primarily derives from the degeneration of ψR1, and could generally be altered by modifying this repeat element. We also showed that the degenerated repeats of CreTA were insusceptible to recombination and thus more stable compared to a typical CRISPR array, which could be exploited to develop highly stable CRISPR-based tools. These data illustrated that repeat degeneration (a common feature of ectopic repeats) improves the stability and specificity of CreTA in protecting CRISPR-Cas, which could have contributed to the widespread occurrence and deep diversification of CRISPR systems.
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Affiliation(s)
| | | | | | - Xifeng Cao
- School of life Sciences, Hebei University, Baoding, Hebei, China
| | - Rui Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xian Shu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Lingyun Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China,College of Plant Protection, Shandong Agricultural University, Taian, Shandong, China
| | - Yihan Zhang
- School of life Sciences, Hebei University, Baoding, Hebei, China,CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hua Xiang
- Correspondence may also be addressed to Hua Xiang.
| | - Ming Li
- To whom correspondence should be addressed. Tel: +86 10 64807064; Fax: +86 10 64807064;
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15
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Wu Q, Cui L, Liu Y, Li R, Dai M, Xia Z, Wu M. CRISPR-Cas systems target endogenous genes to impact bacterial physiology and alter mammalian immune responses. MOLECULAR BIOMEDICINE 2022; 3:22. [PMID: 35854035 PMCID: PMC9296731 DOI: 10.1186/s43556-022-00084-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/25/2022] [Indexed: 11/26/2022] Open
Abstract
CRISPR-Cas systems are an immune defense mechanism that is widespread in archaea and bacteria against invasive phages or foreign genetic elements. In the last decade, CRISPR-Cas systems have been a leading gene-editing tool for agriculture (plant engineering), biotechnology, and human health (e.g., diagnosis and treatment of cancers and genetic diseases), benefitted from unprecedented discoveries of basic bacterial research. However, the functional complexity of CRISPR systems is far beyond the original scope of immune defense. CRISPR-Cas systems are implicated in influencing the expression of physiology and virulence genes and subsequently altering the formation of bacterial biofilm, drug resistance, invasive potency as well as bacterial own physiological characteristics. Moreover, increasing evidence supports that bacterial CRISPR-Cas systems might intriguingly influence mammalian immune responses through targeting endogenous genes, especially those relating to virulence; however, unfortunately, their underlying mechanisms are largely unclear. Nevertheless, the interaction between bacterial CRISPR-Cas systems and eukaryotic cells is complex with numerous mysteries that necessitate further investigation efforts. Here, we summarize the non-canonical functions of CRISPR-Cas that potentially impact bacterial physiology, pathogenicity, antimicrobial resistance, and thereby altering the courses of mammalian immune responses.
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Affiliation(s)
- Qun Wu
- Department of Pediatrics, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Department of Biomedical Sciences, School of Medicine and Health Sciences University of North Dakota, Grand Forks, North Dakota, 58203-9037, USA
| | - Luqing Cui
- Department of Biomedical Sciences, School of Medicine and Health Sciences University of North Dakota, Grand Forks, North Dakota, 58203-9037, USA
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, 430070, P. R. China
| | - Yingying Liu
- Department of Biomedical Sciences, School of Medicine and Health Sciences University of North Dakota, Grand Forks, North Dakota, 58203-9037, USA
| | - Rongpeng Li
- Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province, School of Life Sciences, Jiangsu Normal University, Xuzhou, 221116, China
| | - Menghong Dai
- The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, 430070, P. R. China.
| | - Zhenwei Xia
- Department of Pediatrics, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Min Wu
- Department of Biomedical Sciences, School of Medicine and Health Sciences University of North Dakota, Grand Forks, North Dakota, 58203-9037, USA.
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16
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Huang CJ, Adler BA, Doudna JA. A naturally DNase-free CRISPR-Cas12c enzyme silences gene expression. Mol Cell 2022; 82:2148-2160.e4. [PMID: 35659325 DOI: 10.1016/j.molcel.2022.04.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/14/2022] [Accepted: 04/14/2022] [Indexed: 12/26/2022]
Abstract
Used widely for genome editing, CRISPR-Cas enzymes provide RNA-guided immunity to microbes by targeting foreign nucleic acids for cleavage. We show here that the native activity of CRISPR-Cas12c protects bacteria from phage infection by binding to DNA targets without cleaving them, revealing that antiviral interference can be accomplished without chemical attack on the invader or general metabolic disruption in the host. Biochemical experiments demonstrate that Cas12c is a site-specific ribonuclease capable of generating mature CRISPR RNAs (crRNAs) from precursor transcripts. Furthermore, we find that crRNA maturation is essential for Cas12c-mediated DNA targeting. These crRNAs direct double-stranded DNA binding by Cas12c using a mechanism that precludes DNA cutting. Nevertheless, Cas12c represses transcription and can defend bacteria against lytic bacteriophage infection when targeting an essential phage gene. Together, these results show that Cas12c employs targeted DNA binding to provide antiviral immunity in bacteria, providing a native DNase-free pathway for transient antiviral immunity.
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Affiliation(s)
- Carolyn J Huang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Benjamin A Adler
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA; California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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17
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Kurihara N, Nakagawa R, Hirano H, Okazaki S, Tomita A, Kobayashi K, Kusakizako T, Nishizawa T, Yamashita K, Scott DA, Nishimasu H, Nureki O. Structure of the type V-C CRISPR-Cas effector enzyme. Mol Cell 2022; 82:1865-1877.e4. [PMID: 35366394 PMCID: PMC9522604 DOI: 10.1016/j.molcel.2022.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 12/27/2021] [Accepted: 02/28/2022] [Indexed: 01/02/2023]
Abstract
RNA-guided CRISPR-Cas nucleases are widely used as versatile genome-engineering tools. Recent studies identified functionally divergent type V Cas12 family enzymes. Among them, Cas12c2 binds a CRISPR RNA (crRNA) and a trans-activating crRNA (tracrRNA) and recognizes double-stranded DNA targets with a short TN PAM. Here, we report the cryo-electron microscopy structures of the Cas12c2-guide RNA binary complex and the Cas12c2-guide RNA-target DNA ternary complex. The structures revealed that the crRNA and tracrRNA form an unexpected X-junction architecture, and that Cas12c2 recognizes a single T nucleotide in the PAM through specific hydrogen-bonding interactions with two arginine residues. Furthermore, our biochemical analyses indicated that Cas12c2 processes its precursor crRNA to a mature crRNA using the RuvC catalytic site through a unique mechanism. Collectively, our findings improve the mechanistic understanding of diverse type V CRISPR-Cas effectors.
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Affiliation(s)
- Nina Kurihara
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryoya Nakagawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hisato Hirano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sae Okazaki
- Structural Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kan Kobayashi
- PeptiDream Inc., 3-25-23 Tonomachi, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture 210-0821, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomohiro Nishizawa
- Graduate School of Medical Life Science, Yokohama City University, Yokohama 230-0045, Japan
| | - Keitaro Yamashita
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | | | - Hiroshi Nishimasu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Structural Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan; Inamori Research Institute for Science, 620 Suiginya-cho, Shimogyo-ku, Kyoto 600-8411, Japan.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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18
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van Riet J, Saha C, Strepis N, Brouwer RWW, Martens-Uzunova ES, van de Geer WS, Swagemakers SMA, Stubbs A, Halimi Y, Voogd S, Tanmoy AM, Komor MA, Hoogstrate Y, Janssen B, Fijneman RJA, Niknafs YS, Chinnaiyan AM, van IJcken WFJ, van der Spek PJ, Jenster G, Louwen R. CRISPRs in the human genome are differentially expressed between malignant and normal adjacent to tumor tissue. Commun Biol 2022; 5:338. [PMID: 35396392 PMCID: PMC8993844 DOI: 10.1038/s42003-022-03249-4] [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] [Received: 11/18/2020] [Accepted: 03/09/2022] [Indexed: 11/09/2022] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) have been identified in bacteria, archaea and mitochondria of plants, but not in eukaryotes. Here, we report the discovery of 12,572 putative CRISPRs randomly distributed across the human chromosomes, which we termed hCRISPRs. By using available transcriptome datasets, we demonstrate that hCRISPRs are distinctively expressed as small non-coding RNAs (sncRNAs) in cell lines and human tissues. Moreover, expression patterns thereof enabled us to distinguish normal from malignant tissues. In prostate cancer, we confirmed the differential hCRISPR expression between normal adjacent and malignant primary prostate tissue by RT-qPCR and demonstrate that the SHERLOCK and DETECTR dipstick tools are suitable to detect these sncRNAs. We anticipate that the discovery of CRISPRs in the human genome can be further exploited for diagnostic purposes in cancer and other medical conditions, which certainly will lead to the development of point-of-care tests based on the differential expression of the hCRISPRs. CRISPR elements in the human genome are expressed in both healthy tissues and tumors but with distinct patterns, representing a potential biomarker for cancer.
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Affiliation(s)
- Job van Riet
- Department of Urology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands.,Cancer Computational Biology Center, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands.,Department of Medical Oncology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Chinmoy Saha
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Nikolaos Strepis
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Rutger W W Brouwer
- Center for Biomics, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Elena S Martens-Uzunova
- Department of Urology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Wesley S van de Geer
- Cancer Computational Biology Center, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands.,Department of Medical Oncology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Sigrid M A Swagemakers
- Clinical Bioinformatics, Department of Pathology, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Andrew Stubbs
- Clinical Bioinformatics, Department of Pathology, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Yassir Halimi
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Sanne Voogd
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Arif Mohammad Tanmoy
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands.,Child Health Research Foundation, 23/2 SEL Huq Skypark, Block-B, Khilji Rd, Dhaka, 1207, Bangladesh
| | - Malgorzata A Komor
- Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, Netherlands.,Oncoproteomics Laboratory, Department of Medical Oncology, VU University Medical Center, Amsterdam, Netherlands
| | - Youri Hoogstrate
- Department of Neurology, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | | | - Remond J A Fijneman
- Translational Gastrointestinal Oncology, Department of Pathology, Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Yashar S Niknafs
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Arul M Chinnaiyan
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | - Peter J van der Spek
- Clinical Bioinformatics, Department of Pathology, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Guido Jenster
- Department of Urology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Rogier Louwen
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, Rotterdam, Netherlands.
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19
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Yuan C, Li P, Qing C, Kou Z, Wang H. Different Regulatory Strategies of Arsenite Oxidation by Two Isolated Thermus tengchongensis Strains From Hot Springs. Front Microbiol 2022; 13:817891. [PMID: 35359718 PMCID: PMC8963470 DOI: 10.3389/fmicb.2022.817891] [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] [Received: 11/18/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Arsenic is a ubiquitous constituent in geothermal fluids. Thermophiles represented by Thermus play vital roles in its transformation in geothermal fluids. In this study, two Thermus tengchongensis strains, named as 15Y and 15W, were isolated from arsenic-rich geothermal springs and found different arsenite oxidation behaviors with different oxidation strategies. Arsenite oxidation of both strains occurred at different growth stages, and two enzyme-catalyzed reaction kinetic models were observed. The arsenite oxidase of Thermus strain 15W performed better oxidation activity, exhibiting typical Michaelis–Menten kinetics. The kinetic parameter of arsenite oxidation in whole cell showed a Vmax of 18.48 μM min–1 and KM of 343 μM. Both of them possessed the arsenite oxidase-coding genes aioB and aioA. However, the expression of gene aioBA was constitutive in strain 15W, whereas it was induced by arsenite in strain 15Y. Furthermore, strain 15Y harbored an intact aio operon including the regulatory gene of the ArsR family, whereas a genetic inversion of an around 128-kbp fragment produced the inactivation of this regulator in strain 15W, leading to the constitutive expression of aioBA genes. This study provides a valuable insight into the adaption of thermophiles to extreme environments.
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Affiliation(s)
- Changguo Yuan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China
| | - Ping Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China
- *Correspondence: Ping Li,
| | - Chun Qing
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China
| | - Zhu Kou
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China
| | - Helin Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China University of Geosciences, Wuhan, China
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20
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Klompe SE, Jaber N, Beh LY, Mohabir JT, Bernheim A, Sternberg SH. Evolutionary and mechanistic diversity of Type I-F CRISPR-associated transposons. Mol Cell 2022; 82:616-628.e5. [PMID: 35051352 PMCID: PMC8849592 DOI: 10.1016/j.molcel.2021.12.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/20/2021] [Accepted: 12/16/2021] [Indexed: 02/05/2023]
Abstract
Canonical CRISPR-Cas systems utilize RNA-guided nucleases for targeted cleavage of foreign nucleic acids, whereas some nuclease-deficient CRISPR-Cas complexes have been repurposed to direct the insertion of Tn7-like transposons. Here, we established a bioinformatic and experimental pipeline to comprehensively explore the diversity of Type I-F CRISPR-associated transposons. We report DNA integration for 20 systems and identify a highly active subset that exhibits complete orthogonality in transposon DNA mobilization. We reveal the modular nature of CRISPR-associated transposons by exploring the horizontal acquisition of targeting modules and by characterizing a system that encodes both a programmable, RNA-dependent pathway, and a fixed, RNA-independent pathway. Finally, we analyzed transposon-encoded cargo genes and found the striking presence of anti-phage defense systems, suggesting a role in transmitting innate immunity between bacteria. Collectively, this study substantially advances our biological understanding of CRISPR-associated transposon function and expands the suite of RNA-guided transposases for programmable, large-scale genome engineering.
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MESH Headings
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- CRISPR-Cas Systems
- Clustered Regularly Interspaced Short Palindromic Repeats
- DNA Transposable Elements/genetics
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- Escherichia coli/genetics
- Escherichia coli/immunology
- Escherichia coli/metabolism
- Evolution, Molecular
- Gene Editing
- Gene Expression Regulation, Bacterial
- Genetic Variation
- Immunity, Innate
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- Transposases/genetics
- Transposases/metabolism
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Affiliation(s)
- Sanne E Klompe
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Nora Jaber
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Leslie Y Beh
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Jason T Mohabir
- Department of Computer Science, Columbia University, New York, NY 10027, USA
| | - Aude Bernheim
- French National Institute of Health and Medical Research (INSERM), University of Paris, Paris, France
| | - Samuel H Sternberg
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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21
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Alternative functions of CRISPR-Cas systems in the evolutionary arms race. Nat Rev Microbiol 2022; 20:351-364. [PMID: 34992260 DOI: 10.1038/s41579-021-00663-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2021] [Indexed: 12/14/2022]
Abstract
CRISPR-Cas systems of bacteria and archaea comprise chromosomal loci with typical repetitive clusters and associated genes encoding a range of Cas proteins. Adaptation of CRISPR arrays occurs when virus-derived and plasmid-derived sequences are integrated as new CRISPR spacers. Cas proteins use CRISPR-derived RNA guides to specifically recognize and cleave nucleic acids of invading mobile genetic elements. Apart from this role as an adaptive immune system, some CRISPR-associated nucleases are hijacked by mobile genetic elements: viruses use them to attack their prokaryotic hosts, and transposons have adopted CRISPR systems for guided transposition. In addition, some CRISPR-Cas systems control the expression of genes involved in bacterial physiology and virulence. Moreover, pathogenic bacteria may use their Cas nuclease activity indirectly to evade the human immune system or directly to invade the nucleus and damage the chromosomal DNA of infected human cells. Thus, the evolutionary arms race has led to the expansion of exciting variations in CRISPR mechanisms and functionalities. In this Review, we explore the latest insights into the diverse functions of CRISPR-Cas systems beyond adaptive immunity and discuss the implications for the development of CRISPR-based applications.
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22
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Abstract
The principal biological function of bacterial and archaeal CRISPR systems is RNA-guided adaptive immunity against viruses and other mobile genetic elements (MGEs). These systems show remarkable evolutionary plasticity and functional versatility at multiple levels, including both the defense mechanisms that lead to direct, specific elimination of the target DNA or RNA and those that cause programmed cell death (PCD) or induction of dormancy. This flexibility is also evident in the recruitment of CRISPR systems for nondefense functions. Defective CRISPR systems or individual CRISPR components have been recruited by transposons for RNA-guided transposition, by plasmids for interplasmid competition, and by viruses for antidefense and interviral conflicts. Additionally, multiple highly derived CRISPR variants of yet unknown functions have been discovered. A major route of innovation in CRISPR evolution is the repurposing of diverged repeat variants encoded outside CRISPR arrays for various structural and regulatory functions. The evolutionary plasticity and functional versatility of CRISPR systems are striking manifestations of the ubiquitous interplay between defense and “normal” cellular functions. The CRISPR systems show remarkable functional versatility beyond their principal function as an adaptive immune mechanism. This Essay discusses how derived CRISPR systems have been recruited by transposons on multiple occasions and mediate RNA-guided transposition; derived CRISPR RNAs are frequently recruited for regulatory functions.
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Affiliation(s)
- Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
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23
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Sharma S, Sharma CM. Identification of RNA Binding Partners of CRISPR-Cas Proteins in Prokaryotes Using RIP-Seq. Methods Mol Biol 2022; 2404:111-133. [PMID: 34694606 DOI: 10.1007/978-1-0716-1851-6_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
CRISPR-Cas systems consist of a complex ribonucleoprotein (RNP) machinery encoded in prokaryotic genomes to confer adaptive immunity against foreign mobile genetic elements. Of these, especially the class 2, Type II CRISPR-Cas9 RNA-guided systems with single protein effector modules have recently received much attention for their application as programmable DNA scissors that can be used for genome editing in eukaryotes. While many studies have concentrated their efforts on improving RNA-mediated DNA targeting with these Type II systems, little is known about the factors that modulate processing or binding of the CRISPR RNA (crRNA) guides and the trans-activating tracrRNA to the nuclease protein Cas9, and whether Cas9 can also potentially interact with other endogenous RNAs encoded within the host genome. Here, we describe RIP-seq as a method to globally identify the direct RNA binding partners of CRISPR-Cas RNPs using the Cas9 nuclease as an example. RIP-seq combines co-immunoprecipitation (coIP) of an epitope-tagged Cas9 followed by isolation and deep sequencing analysis of its co-purified bound RNAs. This method can not only be used to study interactions of Cas9 with its known interaction partners, crRNAs and tracrRNA in native systems, but also to reveal potential additional RNA substrates of Cas9. For example, in RIP-seq analysis of Cas9 from the foodborne pathogen Campylobacter jejuni (CjeCas9), we recently identified several endogenous RNAs bound to CjeCas9 RNP in a crRNA-dependent manner, leading to the discovery of PAM-independent RNA cleavage activity of CjeCas9 as well as non-canonical crRNAs. RIP-seq can be easily adapted to any other effector RNP of choice from other CRISPR-Cas systems, allowing for the identification of target RNAs. Deciphering novel RNA-protein interactions for CRISPR-Cas proteins within host bacterial genomes will lead to a better understanding of the molecular mechanisms and functions of these systems and enable us to use the in vivo identified interaction rules as design principles for nucleic acid-targeting applications, fitted to each nuclease of interest.
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Affiliation(s)
- Sahil Sharma
- Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
| | - Cynthia M Sharma
- Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
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24
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Yang F, Xu L, Liang L, Liang W, Li J, Lin D, Dai M, Zhou D, Li Y, Chen Y, Zhao H, Tian GB, Feng S. The Involvement of Mycobacterium Type III-A CRISPR-Cas System in Oxidative Stress. Front Microbiol 2021; 12:774492. [PMID: 34956138 PMCID: PMC8696179 DOI: 10.3389/fmicb.2021.774492] [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: 09/12/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Type I and type II CRISPR-Cas systems are employed to evade host immunity by targeting interference of bacteria’s own genes. Although Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, possesses integrated type III-A CRISPR-Cas system, its role in mycobacteria remains obscure. Here, we observed that seven cas genes (csm2∼5, cas10, cas6) were upregulated in Mycobacterium bovis BCG under oxidative stress treatment, indicating the role of type III-A CRISPR-Cas system in oxidative stress. To explore the functional role of type III-A CRISPR-Cas system, TCC (Type III-A CRISPR-Cas system, including cas6, cas10, and csm2-6) mutant was generated. Deletion of TCC results in increased sensitivity in response to hydrogen peroxide and reduced cell envelope integrity. Analysis of RNA-seq dataset revealed that TCC impacted on the oxidation-reduction process and the composition of cell wall which is essential for mycobacterial envelop integrity. Moreover, disrupting TCC led to poor intracellular survival in vivo and in vitro. Finally, we showed for the first time that TCC contributed to the regulation of regulatory T cell population, supporting a role of TCC in modulating host immunity. Our finding reveals the important role of TCC in cell envelop homeostasis. Our work also highlights type III-A CRISPR-Cas system as an important factor for intracellular survival and host immunoregulation in mycobacteria, thus may be a potential target for therapy.
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Affiliation(s)
- Fan Yang
- Department of Microbiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Lingqing Xu
- Department of Clinical Laboratory, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, China
| | - Lujie Liang
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Wanfei Liang
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Jiachen Li
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Daixi Lin
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Min Dai
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Dianrong Zhou
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yaxin Li
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Yong Chen
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Hui Zhao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Guo-Bao Tian
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
| | - Siyuan Feng
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou, China
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25
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Abstract
CRISPR-Cas adaptive immune systems in bacteria and archaea utilize short CRISPR RNAs (crRNAs) to guide sequence-specific recognition and clearance of foreign genetic material. Multiple crRNAs are stored together in a compact format called a CRISPR array that is transcribed and processed into the individual crRNAs. While the exact processing mechanisms vary widely, some CRISPR-Cas systems, including those encoding the Cas9 nuclease, rely on a trans-activating crRNA (tracrRNA). The tracrRNA was discovered in 2011 and was quickly co-opted to create single-guide RNAs as core components of CRISPR-Cas9 technologies. Since then, further studies have uncovered processes extending beyond the traditional role of tracrRNA in crRNA biogenesis, revealed Cas nucleases besides Cas9 that are dependent on tracrRNAs, and established new applications based on tracrRNA engineering. In this review, we describe the biology of the tracrRNA and how its ongoing characterization has garnered new insights into prokaryotic immune defense and enabled key technological advances.
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Affiliation(s)
- Chunyu Liao
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany;
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080 Würzburg, Germany;
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
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26
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Ratner HK, Weiss DS. crRNA complementarity shifts endogenous CRISPR-Cas systems between transcriptional repression and DNA defense. RNA Biol 2021; 18:1560-1573. [PMID: 33733999 PMCID: PMC8583161 DOI: 10.1080/15476286.2021.1878335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/10/2021] [Accepted: 01/13/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems are prokaryotic adaptive immune systems that recognize and cleave nucleic acid targets using small RNAs called CRISPR RNAs (crRNAs) to guide Cas protein(s). There is increasing evidence for the broader endogenous roles of these systems. The CRISPR-Cas9 system of Francisella novicida also represses endogenous transcription using a non-canonical small RNA (scaRNA). We examined whether the crRNAs of the native F. novicida CRISPR-Cas systems, Cas12a and Cas9, can guide transcriptional repression. Both systems repressed mRNA transcript levels when crRNA-target complementarity was limited, and led to target cleavage with extended complementarity. Using these parameters we engineered the CRISPR array of Cas12a to guide the transcriptional repression of a new and endogenous target. Since the majority of crRNA targets remain unidentified, this work suggests that a re-analysis of crRNAs for endogenous targets with limited complementarity could reveal new, diverse regulatory roles for CRISPR-Cas systems in prokaryotic biology.
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Affiliation(s)
- Hannah K. Ratner
- Microbiology and Molecular Genetics Program, Emory University, Atlanta, GA, USA
- Emory Vaccine Center, Emory University, Atlanta, GA, USA
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - David S. Weiss
- Emory Vaccine Center, Emory University, Atlanta, GA, USA
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
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27
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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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28
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Jiao C, Sharma S, Dugar G, Peeck NL, Bischler T, Wimmer F, Yu Y, Barquist L, Schoen C, Kurzai O, Sharma CM, Beisel CL. Noncanonical crRNAs derived from host transcripts enable multiplexable RNA detection by Cas9. Science 2021; 372:941-948. [PMID: 33906967 PMCID: PMC8224270 DOI: 10.1126/science.abe7106] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 04/09/2021] [Indexed: 12/19/2022]
Abstract
CRISPR-Cas systems recognize foreign genetic material using CRISPR RNAs (crRNAs). In type II systems, a trans-activating crRNA (tracrRNA) hybridizes to crRNAs to drive their processing and utilization by Cas9. While analyzing Cas9-RNA complexes from Campylobacter jejuni, we discovered tracrRNA hybridizing to cellular RNAs, leading to formation of "noncanonical" crRNAs capable of guiding DNA targeting by Cas9. Our discovery inspired the engineering of reprogrammed tracrRNAs that link the presence of any RNA of interest to DNA targeting with different Cas9 orthologs. This capability became the basis for a multiplexable diagnostic platform termed LEOPARD (leveraging engineered tracrRNAs and on-target DNAs for parallel RNA detection). LEOPARD allowed simultaneous detection of RNAs from different viruses in one test and distinguished severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its D614G (Asp614→Gly) variant with single-base resolution in patient samples.
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Affiliation(s)
- Chunlei Jiao
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Sahil Sharma
- Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg. 97080 Würzburg, Germany
| | - Gaurav Dugar
- Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg. 97080 Würzburg, Germany
| | - Natalia L Peeck
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Thorsten Bischler
- Core Unit Systems Medicine, University of Würzburg, 97080 Würzburg, Germany
| | - Franziska Wimmer
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Yanying Yu
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
| | - Christoph Schoen
- Institute for Hygiene and Microbiology, University of Würzburg, 97080 Würzburg, Germany
| | - Oliver Kurzai
- Institute for Hygiene and Microbiology, University of Würzburg, 97080 Würzburg, Germany
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, 07745 Germany
| | - Cynthia M Sharma
- Molecular Infection Biology II, Institute of Molecular Infection Biology, University of Würzburg. 97080 Würzburg, Germany.
| | - Chase L Beisel
- Helmholtz Institute for RNA-based Infection Research (HIRI)/Helmholtz-Centre for Infection Research (HZI), 97080 Würzburg, Germany.
- Medical Faculty, University of Würzburg, 97080 Würzburg, Germany
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29
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Li M, Gong L, Cheng F, Yu H, Zhao D, Wang R, Wang T, Zhang S, Zhou J, Shmakov SA, Koonin EV, Xiang H. Toxin-antitoxin RNA pairs safeguard CRISPR-Cas systems. Science 2021; 372:372/6541/eabe5601. [PMID: 33926924 DOI: 10.1126/science.abe5601] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/29/2020] [Accepted: 03/10/2021] [Indexed: 12/18/2022]
Abstract
CRISPR-Cas systems provide RNA-guided adaptive immunity in prokaryotes. We report that the multisubunit CRISPR effector Cascade transcriptionally regulates a toxin-antitoxin RNA pair, CreTA. CreT (Cascade-repressed toxin) is a bacteriostatic RNA that sequesters the rare arginine tRNAUCU (transfer RNA with anticodon UCU). CreA is a CRISPR RNA-resembling antitoxin RNA, which requires Cas6 for maturation. The partial complementarity between CreA and the creT promoter directs Cascade to repress toxin transcription. Thus, CreA becomes antitoxic only in the presence of Cascade. In CreTA-deleted cells, cascade genes become susceptible to disruption by transposable elements. We uncover several CreTA analogs associated with diverse archaeal and bacterial CRISPR-cas loci. Thus, toxin-antitoxin RNA pairs can safeguard CRISPR immunity by making cells addicted to CRISPR-Cas, which highlights the multifunctionality of Cas proteins and the intricate mechanisms of CRISPR-Cas regulation.
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Affiliation(s)
- Ming Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China. .,CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Luyao Gong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Feiyue Cheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Dahe Zhao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Rui Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Tian Wang
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Shengjie Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Jian Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Sergey A Shmakov
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Hua Xiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China. .,College of Life Science, University of Chinese Academy of Sciences, Beijing, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
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30
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Märkle P, Maier LK, Maaß S, Hirschfeld C, Bartel J, Becher D, Voß B, Marchfelder A. A Small RNA Is Linking CRISPR-Cas and Zinc Transport. Front Mol Biosci 2021; 8:640440. [PMID: 34055875 PMCID: PMC8155600 DOI: 10.3389/fmolb.2021.640440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 03/01/2021] [Indexed: 11/13/2022] Open
Abstract
The function and mode of action of small regulatory RNAs is currently still understudied in archaea. In the halophilic archaeon Haloferax volcanii, a plethora of sRNAs have been identified; however, in-depth functional analysis is missing for most of them. We selected a small RNA (s479) from Haloferax volcanii for detailed characterization. The sRNA gene is encoded between a CRISPR RNA locus and the Cas protein gene cluster, and the s479 deletion strain is viable and was characterized in detail. Transcriptome studies of wild-type Haloferax cells and the deletion mutant revealed upregulation of six genes in the deletion strain, showing that this sRNA has a clearly defined function. Three of the six upregulated genes encode potential zinc transporter proteins (ZnuA1, ZnuB1, and ZnuC1) suggesting the involvement of s479 in the regulation of zinc transport. Upregulation of these genes in the deletion strain was confirmed by northern blot and proteome analyses. Furthermore, electrophoretic mobility shift assays demonstrate a direct interaction of s479 with the target znuC1 mRNA. Proteome comparison of wild-type and deletion strains further expanded the regulon of s479 deeply rooting this sRNA within the metabolism of H. volcanii especially the regulation of transporter abundance. Interestingly, s479 is not only encoded next to CRISPR-cas genes, but the mature s479 contains a crRNA-like 5' handle, and experiments with Cas protein deletion strains indicate maturation by Cas6 and interaction with Cas proteins. Together, this might suggest that the CRISPR-Cas system is involved in s479 function.
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Affiliation(s)
- Pascal Märkle
- Department of Biology II, Ulm University, Ulm, Germany
| | | | - Sandra Maaß
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Claudia Hirschfeld
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Jürgen Bartel
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Dörte Becher
- Department of Microbial Proteomics, Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Björn Voß
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
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31
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Steinum TM, Turgay E, Yardımcı RE, Småge SB, Karataş S. Tenacibaculum maritimum CRISPR loci analysis and evaluation of isolate spoligotyping. J Appl Microbiol 2021; 131:1848-1857. [PMID: 33905598 DOI: 10.1111/jam.15116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Indexed: 11/27/2022]
Abstract
AIMS We performed in silico analysis of CRISPRcas loci from Tenacibaculum maritimum, evaluated spoligotyping as a subtyping method and genotyped uncharacterized Turkish isolates from European sea bass by multilocus sequence typing (MLST). METHODS AND RESULTS Spoligotyping was performed with primers designed to allow amplification and sequencing of whole CRISPR-arrays from 23 T. maritimum isolates. Twenty-three completed/draft genomes were also downloaded from the NCBI database and analysed. MLST of Turkish isolates was achieved with a well-established 7-gene scheme. Tenacibaculum maritimum genomes carry a structurally complete but partially defective class II CRISPRcas locus due to known amino acid substitutions in encoded Cas9 proteins. Our spacer identification suggests that the host range of bacteriophage P2559Y and Vibrio phage nt-1 include T. maritimum and that the most recurrent infection recorded by isolates has been with Tenacibaculum phage PTm5. Thirty-eight isolates with this CRISPRcas locus belonged to 25 spoligotypes and to 24 sequence types by MLST, respectively. According to MLST, T. maritimum isolates from Turkey are most related to previously defined sequence types ST3, ST40 and ST41 isolates from Spain, Malta and France. CONCLUSIONS The evaluated spoligotyping offers discriminatory power comparable to MLST. SIGNIFICANCE AND IMPACT OF THE STUDY Spoligotyping has potential as a quick, easy and cheap tool for subtyping of T. maritimum isolates.
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Affiliation(s)
- T M Steinum
- Department of Molecular Biology and Genetics, Faculty of Sciences, Istanbul University, Istanbul, Turkey
| | - E Turgay
- Department of Aquaculture and Fish Diseases, Faculty of Aquatic Sciences, Istanbul University, Istanbul, Turkey
| | - R E Yardımcı
- Department of Aquaculture and Fish Diseases, Faculty of Aquatic Sciences, Istanbul University, Istanbul, Turkey
| | | | - S Karataş
- Department of Aquaculture and Fish Diseases, Faculty of Aquatic Sciences, Istanbul University, Istanbul, Turkey
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32
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Workman RE, Pammi T, Nguyen BTK, Graeff LW, Smith E, Sebald SM, Stoltzfus MJ, Euler CW, Modell JW. A natural single-guide RNA repurposes Cas9 to autoregulate CRISPR-Cas expression. Cell 2021; 184:675-688.e19. [PMID: 33421369 DOI: 10.1016/j.cell.2020.12.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 09/24/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022]
Abstract
CRISPR-Cas systems provide prokaryotes with acquired immunity against viruses and plasmids, but how these systems are regulated to prevent autoimmunity is poorly understood. Here, we show that in the S. pyogenes CRISPR-Cas system, a long-form transactivating CRISPR RNA (tracr-L) folds into a natural single guide that directs Cas9 to transcriptionally repress its own promoter (Pcas). Further, we demonstrate that Pcas serves as a critical regulatory node. De-repression causes a dramatic 3,000-fold increase in immunization rates against viruses; however, heightened immunity comes at the cost of increased autoimmune toxicity. Using bioinformatic analyses, we provide evidence that tracrRNA-mediated autoregulation is widespread in type II-A CRISPR-Cas systems. Collectively, we unveil a new paradigm for the intrinsic regulation of CRISPR-Cas systems by natural single guides, which may facilitate the frequent horizontal transfer of these systems into new hosts that have not yet evolved their own regulatory strategies.
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Affiliation(s)
- Rachael E Workman
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Teja Pammi
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Binh T K Nguyen
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Leonardo W Graeff
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Suzanne M Sebald
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Marie J Stoltzfus
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chad W Euler
- Department of Medical Laboratory Sciences, Hunter College, CUNY, New York, NY 10065, USA; Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Joshua W Modell
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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33
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Newsom S, Parameshwaran HP, Martin L, Rajan R. The CRISPR-Cas Mechanism for Adaptive Immunity and Alternate Bacterial Functions Fuels Diverse Biotechnologies. Front Cell Infect Microbiol 2021; 10:619763. [PMID: 33585286 PMCID: PMC7876343 DOI: 10.3389/fcimb.2020.619763] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/14/2020] [Indexed: 12/26/2022] Open
Abstract
Bacterial and archaeal CRISPR-Cas systems offer adaptive immune protection against foreign mobile genetic elements (MGEs). This function is regulated by sequence specific binding of CRISPR RNA (crRNA) to target DNA/RNA, with an additional requirement of a flanking DNA motif called the protospacer adjacent motif (PAM) in certain CRISPR systems. In this review, we discuss how the same fundamental mechanism of RNA-DNA and/or RNA-RNA complementarity is utilized by bacteria to regulate two distinct functions: to ward off intruding genetic materials and to modulate diverse physiological functions. The best documented examples of alternate functions are bacterial virulence, biofilm formation, adherence, programmed cell death, and quorum sensing. While extensive complementarity between the crRNA and the targeted DNA and/or RNA seems to constitute an efficient phage protection system, partial complementarity seems to be the key for several of the characterized alternate functions. Cas proteins are also involved in sequence-specific and non-specific RNA cleavage and control of transcriptional regulator expression, the mechanisms of which are still elusive. Over the past decade, the mechanisms of RNA-guided targeting and auxiliary functions of several Cas proteins have been transformed into powerful gene editing and biotechnological tools. We provide a synopsis of CRISPR technologies in this review. Even with the abundant mechanistic insights and biotechnology tools that are currently available, the discovery of new and diverse CRISPR types holds promise for future technological innovations, which will pave the way for precision genome medicine.
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Affiliation(s)
- Sydney Newsom
- Department of Chemistry and Biochemistry, Price Family Foundation Structural Biology Center, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, United States
| | - Hari Priya Parameshwaran
- Department of Chemistry and Biochemistry, Price Family Foundation Structural Biology Center, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, United States
| | - Lindsie Martin
- Department of Chemistry and Biochemistry, Price Family Foundation Structural Biology Center, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, United States
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Structural Biology Center, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, United States
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34
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Abstract
Bacteriophages encode diverse anti-CRISPR (Acr) proteins that inhibit CRISPR-Cas immunity during infection of their bacterial hosts. Although detailed mechanisms have been characterized for multiple Acr proteins, an understanding of their role in phage infection biology is just emerging. Here, we review recent work in this area and propose a framework of "phage autonomy" to evaluate CRISPR-immune evasion strategies. During phage infection, Acr proteins are deployed by a tightly regulated "fast on-fast off" transcriptional burst, which is necessary, but insufficient, for CRISPR-Cas inactivation. Instead of a single phage shutting down CRISPR-Cas immunity, a community of acr-carrying phages cooperate to suppress bacterial immunity, displaying low phage autonomy. Enzymatic Acr proteins with novel mechanisms have been recently revealed and are predicted to enhance phage autonomy, while phage DNA protective measures offer the highest phage autonomy observed. These varied Acr mechanisms and strengths also have unexpected impacts on the bacterial populations and competing phages.
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Affiliation(s)
- Yuping Li
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94403, USA
| | - Joseph Bondy-Denomy
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94403, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94403, USA; Innovative Genomics Institute, Berkeley, CA, USA.
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35
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Nobrega FL, Walinga H, Dutilh BE, Brouns SJJ. Prophages are associated with extensive CRISPR-Cas auto-immunity. Nucleic Acids Res 2020; 48:12074-12084. [PMID: 33219687 PMCID: PMC7708048 DOI: 10.1093/nar/gkaa1071] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems require discriminating self from non-self DNA during adaptation and interference. Yet, multiple cases have been reported of bacteria containing self-targeting spacers (STS), i.e. CRISPR spacers targeting protospacers on the same genome. STS has been suggested to reflect potential auto-immunity as an unwanted side effect of CRISPR-Cas defense, or a regulatory mechanism for gene expression. Here we investigated the incidence, distribution, and evasion of STS in over 100 000 bacterial genomes. We found STS in all CRISPR-Cas types and in one fifth of all CRISPR-carrying bacteria. Notably, up to 40% of I-B and I-F CRISPR-Cas systems contained STS. We observed that STS-containing genomes almost always carry a prophage and that STS map to prophage regions in more than half of the cases. Despite carrying STS, genetic deterioration of CRISPR-Cas systems appears to be rare, suggesting a level of escape from the potentially deleterious effects of STS by other mechanisms such as anti-CRISPR proteins and CRISPR target mutations. We propose a scenario where it is common to acquire an STS against a prophage, and this may trigger more extensive STS buildup by primed spacer acquisition in type I systems, without detrimental autoimmunity effects as mechanisms of auto-immunity evasion create tolerance to STS-targeted prophages.
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Affiliation(s)
- Franklin L Nobrega
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands
| | - Hielke Walinga
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands
| | - Bas E Dutilh
- Theoretical Biology and Bioinformatics, Science4Life, Utrecht University, Utrecht, Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, Netherlands.,Kavli Institute of Nanoscience, Delft, Netherlands
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36
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González Plaza JJ. Small RNAs as Fundamental Players in the Transference of Information During Bacterial Infectious Diseases. Front Mol Biosci 2020; 7:101. [PMID: 32613006 PMCID: PMC7308464 DOI: 10.3389/fmolb.2020.00101] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Communication shapes life on Earth. Transference of information has played a paramount role on the evolution of all living or extinct organisms since the appearance of life. Success or failure in this process will determine the prevalence or disappearance of a certain set of genes, the basis of Darwinian paradigm. Among different molecules used for transmission or reception of information, RNA plays a key role. For instance, the early precursors of life were information molecules based in primitive RNA forms. A growing field of research has focused on the contribution of small non-coding RNA forms due to its role on infectious diseases. These are short RNA species that carry out regulatory tasks in cis or trans. Small RNAs have shown their relevance in fine tuning the expression and activity of important regulators of essential genes for bacteria. Regulation of targets occurs through a plethora of mechanisms, including mRNA stabilization/destabilization, driving target mRNAs to degradation, or direct binding to regulatory proteins. Different studies have been conducted during the interplay of pathogenic bacteria with several hosts, including humans, animals, or plants. The sRNAs help the invader to quickly adapt to the change in environmental conditions when it enters in the host, or passes to a free state. The adaptation is achieved by direct targeting of the pathogen genes, or subversion of the host immune system. Pathogens trigger also an immune response in the host, which has been shown as well to be regulated by a wide range of sRNAs. This review focuses on the most recent host-pathogen interaction studies during bacterial infectious diseases, providing the perspective of the pathogen.
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Affiliation(s)
- Juan José González Plaza
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czechia
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37
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Saha C, Mohanraju P, Stubbs A, Dugar G, Hoogstrate Y, Kremers GJ, van Cappellen WA, Horst-Kreft D, Laffeber C, Lebbink JH, Bruens S, Gaskin D, Beerens D, Klunder M, Joosten R, Demmers JAA, van Gent D, Mouton JW, van der Spek PJ, van der Oost J, van Baarlen P, Louwen R. Guide-free Cas9 from pathogenic Campylobacter jejuni bacteria causes severe damage to DNA. SCIENCE ADVANCES 2020; 6:eaaz4849. [PMID: 32596446 PMCID: PMC7299616 DOI: 10.1126/sciadv.aaz4849] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 05/06/2020] [Indexed: 05/11/2023]
Abstract
CRISPR-Cas9 systems are enriched in human pathogenic bacteria and have been linked to cytotoxicity by an unknown mechanism. Here, we show that upon infection of human cells, Campylobacter jejuni secretes its Cas9 (CjeCas9) nuclease into their cytoplasm. Next, a native nuclear localization signal enables CjeCas9 nuclear entry, where it catalyzes metal-dependent nonspecific DNA cleavage leading to cell death. Compared to CjeCas9, native Cas9 of Streptococcus pyogenes (SpyCas9) is more suitable for guide-dependent editing. However, in human cells, native SpyCas9 may still cause some DNA damage, most likely because of its ssDNA cleavage activity. This side effect can be completely prevented by saturation of SpyCas9 with an appropriate guide RNA, which is only partially effective for CjeCas9. We conclude that CjeCas9 plays an active role in attacking human cells rather than in viral defense. Moreover, these unique catalytic features may therefore make CjeCas9 less suitable for genome editing applications.
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Affiliation(s)
- Chinmoy Saha
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | | | - Andrew Stubbs
- Clinical Bioinformatics, Department of Pathology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Gaurav Dugar
- Institute of Molecular Infection Biology (IMIB)/Research Center for Infectious Diseases (ZINF), University of Würzburg, Würzburg, Germany
| | - Youri Hoogstrate
- Clinical Bioinformatics, Department of Pathology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Gert-Jan Kremers
- Optical Imaging Center, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | | | - Deborah Horst-Kreft
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Charlie Laffeber
- Department of Molecular Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Joyce H.G. Lebbink
- Department of Molecular Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- Department of Radiation Oncology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Serena Bruens
- Department of Molecular Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Duncan Gaskin
- Institute of Food Research, Gut Health and Food Safety Programme, Norwich Research Park, Norwich, UK
| | - Dior Beerens
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Maarten Klunder
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - Rob Joosten
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - Jeroen A. A. Demmers
- Proteomics Center, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Dik van Gent
- Department of Molecular Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Johan W. Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Peter J. van der Spek
- Clinical Bioinformatics, Department of Pathology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - Peter van Baarlen
- Host-Microbe Interactomics Group, University of Wageningen, Wageningen, Netherlands
| | - Rogier Louwen
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
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38
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Francisella novicida CRISPR-Cas Systems Can Functionally Complement Each Other in DNA Defense while Providing Target Flexibility. J Bacteriol 2020; 202:JB.00670-19. [PMID: 32284320 DOI: 10.1128/jb.00670-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/11/2020] [Indexed: 01/03/2023] Open
Abstract
CRISPR-Cas systems are prokaryotic adaptive immune systems that facilitate protection of bacteria and archaea against infection by external mobile genetic elements. The model pathogen Francisella novicida encodes a CRISPR-Cas12a (FnoCas12a) system and a CRISPR-Cas9 (FnoCas9) system, the latter of which has an additional and noncanonical function in bacterial virulence. Here, we investigated and compared the functional roles of the FnoCas12a and FnoCas9 systems in transformation inhibition and bacterial virulence. Unlike FnoCas9, FnoCas12a was not required for F. novicida virulence. However, both systems were highly effective at plasmid restriction and acted independently of each other. We further identified a critical protospacer-adjacent motif (PAM) necessary for transformation inhibition by FnoCas12a, demonstrating a greater flexibility for target identification by FnoCas12a than previously appreciated and a specificity that is distinct from that of FnoCas9. The effectors of the two systems exhibited different patterns of expression at the mRNA level, suggesting that they may confer distinct benefits to the bacterium in diverse environments. These data suggest that due to the differences between the two CRISPR-Cas systems, together they may provide F. novicida with a more comprehensive defense against foreign nucleic acids. Finally, we demonstrated that the FnoCas12a and FnoCas9 machineries could be simultaneously engineered to restrict the same nonnative target, thereby expanding the toolset for prokaryotic genome manipulation.IMPORTANCE CRISPR-Cas9 and CRISPR-Cas12a systems have been widely commandeered for genome engineering. However, they originate in prokaryotes, where they function as adaptive immune systems. The details of this activity and relationship between these systems within native host organisms have been minimally explored. The human pathogen Francisella novicida contains both of these systems, with the Cas9 system also exhibiting a second activity, modulating virulence through transcriptional regulation. We compared and contrasted the ability of these two systems to control virulence and restrict DNA within their native host bacterium, highlighting differences and similarities in these two functions. Collectively, our results indicate that these two distinct and reprogrammable endogenous systems provide F. novicida with a more comprehensive defense against mobile genetic elements.
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39
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Wimmer F, Beisel CL. CRISPR-Cas Systems and the Paradox of Self-Targeting Spacers. Front Microbiol 2020; 10:3078. [PMID: 32038537 PMCID: PMC6990116 DOI: 10.3389/fmicb.2019.03078] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas immune systems in bacteria and archaea record prior infections as spacers within each system’s CRISPR arrays. Spacers are normally derived from invasive genetic material and direct the immune system to complementary targets as part of future infections. However, not all spacers appear to be derived from foreign genetic material and instead can originate from the host genome. Their presence poses a paradox, as self-targeting spacers would be expected to induce an autoimmune response and cell death. In this review, we discuss the known frequency of self-targeting spacers in natural CRISPR-Cas systems, how these spacers can be incorporated into CRISPR arrays, and how the host can evade lethal attack. We also discuss how self-targeting spacers can become the basis for alternative functions performed by CRISPR-Cas systems that extend beyond adaptive immunity. Overall, the acquisition of genome-targeting spacers poses a substantial risk but can aid in the host’s evolution and potentially lead to or support new functionalities.
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Affiliation(s)
- Franziska Wimmer
- Helmholtz Institute for RNA-Based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Chase L Beisel
- Helmholtz Institute for RNA-Based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.,Medical Faculty, University of Würzburg, Würzburg, Germany
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40
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Milicevic O, Repac J, Bozic B, Djordjevic M, Djordjevic M. A Simple Criterion for Inferring CRISPR Array Direction. Front Microbiol 2019; 10:2054. [PMID: 31551987 PMCID: PMC6737040 DOI: 10.3389/fmicb.2019.02054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022] Open
Abstract
Inferring transcriptional direction (orientation) of the CRISPR array is essential for many applications, including systematically investigating non-canonical CRISPR/Cas functions. The standard method, CRISPRDirection (embedded within CRISPRCasFinder), fails to predict the orientation (ND predictions) for ∼37% of the classified CRISPR arrays (>2200 loci); this goes up to >70% for the II-B subtype where non-canonical functions were first experimentally discovered. Alternatively, Potential Orientation (also embedded within CRISPRCasFinder), has a much smaller frequency of ND predictions but might have significantly lower accuracy. We propose a novel simple criterion, where the CRISPR array direction is assigned according to the direction of its associated cas genes (Cas Orientation). We systematically assess the performance of the three methods (Cas Orientation, CRISPRDirection, and Potential Orientation) across all CRISPR/Cas subtypes, by a mutual crosscheck of their predictions, and by comparing them to the experimental dataset. Interestingly, CRISPRDirection agrees much better with Cas Orientation than with Potential Orientation, despite CRISPRDirection and Potential Orientation being mutually related – Potential Orientation corresponding to one of six (heterogeneous) predictors employed by CRISPRDirection – and being unrelated to Cas Orientation. We find that Cas Orientation has much higher accuracy compared to Potential Orientation and comparable accuracy to CRISPRDirection – while accurately assigning an orientation to ∼95% of the CRISPR arrays that are non-determined by CRISPRDirection. Cas Orientation is, at the same time, simple to employ, requiring only (routine for prokaryotes) the prediction of the associated protein coding gene direction.
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Affiliation(s)
- Ognjen Milicevic
- School of Medicine, University of Belgrade, Belgrade, Serbia.,Multidisciplinary Ph.D. Program in Biophysics, University of Belgrade, Belgrade, Serbia
| | - Jelena Repac
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Belgrade, Serbia
| | - Bojan Bozic
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Belgrade, Serbia
| | | | - Marko Djordjevic
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Belgrade, Serbia
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41
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Spencer BL, Deng L, Patras KA, Burcham ZM, Sanches GF, Nagao PE, Doran KS. Cas9 Contributes to Group B Streptococcal Colonization and Disease. Front Microbiol 2019; 10:1930. [PMID: 31497003 PMCID: PMC6712506 DOI: 10.3389/fmicb.2019.01930] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/05/2019] [Indexed: 12/20/2022] Open
Abstract
Group B Streptococcus (GBS) is a major opportunistic pathogen in certain adult populations, including pregnant women, and remains a leading etiologic agent of newborn disease. During pregnancy, GBS asymptomatically colonizes the vaginal tract of 20-30% of healthy women, but can be transmitted to the neonate in utero or during birth resulting in neonatal pneumonia, sepsis, meningitis, and subsequently 10-15% mortality regardless of antibiotic treatment. While various GBS virulence factors have been implicated in vaginal colonization and invasive disease, the regulation of many of these factors remains unclear. Recently, CRISPR-associated protein-9 (Cas9), an endonuclease known for its role in CRISPR/Cas immunity, has also been observed to modulate virulence in a number of bacterial pathogens. However, the role of Cas9 in GBS colonization and disease pathogenesis has not been well-studied. We performed allelic replacement of cas9 in GBS human clinical isolates of the hypervirulent sequence-type 17 strain lineage to generate isogenic Δcas9 mutants. Compared to parental strains, Δcas9 mutants were attenuated in murine models of hematogenous meningitis and vaginal colonization and exhibited significantly decreased invasion of human brain endothelium and adherence to vaginal epithelium. To determine if Cas9 alters transcription in GBS, we performed RNA-Seq analysis and found that 353 genes (>17% of the GBS genome) were differentially expressed between the parental WT and Δcas9 mutant strain. Significantly dysregulated genes included those encoding predicted virulence factors, metabolic factors, two-component systems (TCS), and factors important for cell wall formation. These findings were confirmed by qRT-PCR and suggest that Cas9 may regulate a significant portion of the GBS genome. We studied one of the TCS regulators, CiaR, that was significantly downregulated in the Δcas9 mutant strain. RNA-Seq analysis of the WT and ΔciaR strains demonstrated that almost all CiaR-regulated genes were also significantly regulated by Cas9, suggesting that Cas9 may modulate GBS gene expression through other regulators. Further we show that CiaR contributes to GBS vaginal colonization and persistence. Altogether, these data highlight the potential complexity and importance of the non-canonical function of Cas9 in GBS colonization and disease.
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Affiliation(s)
- Brady L. Spencer
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Liwen Deng
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Kathryn A. Patras
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Zachary M. Burcham
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, United States
| | - Glenda F. Sanches
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Roberto Alcântara Gomes Biology Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Prescilla E. Nagao
- Roberto Alcântara Gomes Biology Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Kelly S. Doran
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, San Diego State University, San Diego, CA, United States
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