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Lin W, Li D, Pan L, Li M, Tong Y. Cyanobacteria-cyanophage interactions between freshwater and marine ecosystems based on large-scale cyanophage genomic analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175201. [PMID: 39102952 DOI: 10.1016/j.scitotenv.2024.175201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 07/30/2024] [Accepted: 07/30/2024] [Indexed: 08/07/2024]
Abstract
The disparities in harmful algal blooms dynamics are largely attributed to variations in cyanobacteria populations within aquatic ecosystems. However, cyanobacteria-cyanophage interactions and their role in shaping cyanobacterial populations has been previously underappreciated. To address this knowledge gap, we isolated and sequenced 42 cyanophages from diverse water sources in China, with the majority (n = 35) originating from freshwater sources. We designated these sequences as the "Novel Cyanophage Genome sequence Collection" (NCGC). NCGC displayed notable genetic variations, with 95 % (40/42) of the sequences representing previously unidentified taxonomic ranks. By integrating NCGC with public data of cyanophages and cyanobacteria, we found evidence for more frequent historical cyanobacteria-cyanophage interactions in freshwater ecosystems. This was evidenced by a higher prevalence of prophage integrase-related genes in freshwater cyanophages (37.97 %) than marine cyanophages (7.42 %). In addition, freshwater cyanophages could infect a broader range of cyanobacteria orders (n = 4) than marine ones (n = 0). Correspondingly, freshwater cyanobacteria harbored more defense systems per million base pairs in their genomes, indicating more frequent phage infections. Evolutionary and cyanophage epidemiological studies suggest that interactions between cyanobacteria and cyanophages in freshwater and marine ecosystems are interconnected, and that brackish water can act as a transitional zone for freshwater and marine cyanophages. In conclusion, our research significantly expands the genetic information database of cyanophage, offering a wider selection of cyanophages to control harmful cyanobacterial blooms. Additionally, we represent a pioneering large-scale and comprehensive analysis of cyanobacteria and cyanophage sequencing data, and it provides theoretical guidance for the application of cyanophages in different environments.
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Affiliation(s)
- Wei Lin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Dengfeng Li
- Key Laboratory of Marine Biotechnology of Zhejiang Province, School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Lingting Pan
- Key Laboratory of Marine Biotechnology of Zhejiang Province, School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Mengzhe Li
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), Beijing University of Chemical Technology, Beijing 100029, China.
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2
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Stoltzfus MJ, Workman RE, Keith NC, Modell JW. A dynamic subpopulation of CRISPR-Cas overexpressers allows Streptococcus pyogenes to rapidly respond to phage. Nat Microbiol 2024:10.1038/s41564-024-01748-0. [PMID: 38997519 DOI: 10.1038/s41564-024-01748-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 06/03/2024] [Indexed: 07/14/2024]
Abstract
Many CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated protein) systems, which provide bacteria with adaptive immunity against phages, are transcriptionally repressed in their native hosts. How CRISPR-Cas expression is induced as needed, for example, during a bacteriophage infection, remains poorly understood. In Streptococcus pyogenes, a non-canonical guide RNA tracr-L directs Cas9 to autorepress its own promoter. Here we describe a dynamic subpopulation of cells harbouring single mutations that disrupt Cas9 binding and cause CRISPR-Cas overexpression. Cas9 actively expands this population by elevating mutation rates at the tracr-L target site. Overexpressers show higher rates of memory formation, stronger potency of old memories and a larger memory storage capacity relative to wild-type cells, which are surprisingly vulnerable to phage infection. However, in the absence of phage, CRISPR-Cas overexpression reduces fitness. We propose that CRISPR-Cas overexpressers are critical players in phage defence, enabling bacterial populations to mount rapid transcriptional responses to phage without requiring transient changes in any one cell.
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Affiliation(s)
- Marie J Stoltzfus
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rachael E Workman
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nicholas C Keith
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Joshua W Modell
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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3
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Ghaffarian S, Panahi B. Occurrence and diversity pattern of CRISPR-Cas systems in Acetobacter genus provides insights on adaptive defense mechanisms against to invasive DNAs. Front Microbiol 2024; 15:1357156. [PMID: 39056004 PMCID: PMC11270541 DOI: 10.3389/fmicb.2024.1357156] [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: 12/17/2023] [Accepted: 07/02/2024] [Indexed: 07/28/2024] Open
Abstract
The Acetobacter genus is primarily known for its significance in acetic acid production and its application in various industrial processes. This study aimed to shed light on the prevalence, diversity, and functional implications of CRISPR-Cas systems in the Acetobacter genus using a genome mining approach. The investigation analyzed the CRISPR-Cas architectures and components of 34 Acetobacter species, as well as the evolutionary strategies employed by these bacteria in response to phage invasion and foreign DNA. Furthermore, phylogenetic analysis based on CAS1 protein sequences was performed to gain insights into the evolutionary relationships among Acetobacter strains, with an emphasis on the potential of this protein for genotyping purposes. The results showed that 15 species had orphan, while20 species had complete CRISPR-Cas systems, resulting in an occurrence rate of 38% for complete systems in Acetobacter strains. The predicted complete CRISPR-Cas systems were categorized into I-C, I-F, I-E, and II-C subtypes, with subtype I-E being the most prevalent in Acetobacter. Additionally, spacer homology analysis revealed against such the dynamic interaction between Acetobacter strains and foreign invasive DNAs, emphasizing the pivotal role of CRISPR-Cas systems in defending against such invasions. Furthermore, the investigation of the secondary structures of CRISPR arrays revealed the conserved patterns within subtypes despite variations in repeat sequences. The exploration of protospacer adjacent motifs (PAMs) identified distinct recognition motifs in the flanking regions of protospacers. In conclusion, this research not only contributes to the growing body of knowledge on CRISPR-Cas systems but also establishes a foundation for future studies on the adaptive defense mechanisms of Acetobacter. The findings provide valuable insights into the intricate interplay between bacteria and phages, with implications for industrial applications and potential biotechnological advancements.
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Affiliation(s)
- Sara Ghaffarian
- Department of Cellular and Molecular Biology, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Bahman Panahi
- Department of Genomics, Branch for Northwest & West region, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education and Extension Organization (AREEO), Tabriz, Iran
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4
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Bhattacharya S, Agarwal A, Muniyappa K. Deciphering the Substrate Specificity Reveals that CRISPR-Cas12a Is a Bifunctional Enzyme with Both Endo- and Exonuclease Activities. J Mol Biol 2024; 436:168550. [PMID: 38575054 DOI: 10.1016/j.jmb.2024.168550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/06/2024]
Abstract
The class 2 CRISPR-Cas9 and CRISPR-Cas12a systems, originally described as adaptive immune systems of bacteria and archaea, have emerged as versatile tools for genome-editing, with applications in biotechnology and medicine. However, significantly less is known about their substrate specificity, but such knowledge may provide instructive insights into their off-target cleavage and previously unrecognized mechanism of action. Here, we document that the Acidaminococcus sp. Cas12a (AsCas12a) binds preferentially, and independently of crRNA, to a suite of branched DNA structures, such as the Holliday junction (HJ), replication fork and D-loops, compared with single- or double-stranded DNA, and promotes their degradation. Further, our study revealed that AsCas12a binds to the HJ, specifically at the crossover region, protects it from DNase I cleavage and renders a pair of thymine residues in the HJ homologous core hypersensitive to KMnO4 oxidation, suggesting DNA melting and/or distortion. Notably, these structural changes enabled AsCas12a to resolve HJ into nonligatable intermediates, and subsequently their complete degradation. We further demonstrate that crRNA impedes HJ cleavage by AsCas12a, and that of Lachnospiraceae bacterium Cas12a, without affecting their DNA-binding ability. We identified a separation-of-function variant, which uncouples DNA-binding and DNA cleavage activities of AsCas12a. Importantly, we found robust evidence that AsCas12a endonuclease also has 3'-to-5' and 5'-to-3' exonuclease activity, and that these two activities synergistically promote degradation of DNA, yielding di- and mononucleotides. Collectively, this study significantly advances knowledge about the substrate specificity of AsCas12a and provides important insights into the degradation of different types of DNA substrates.
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Affiliation(s)
- Supreet Bhattacharya
- Department of Biochemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Ankit Agarwal
- Department of Biochemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru 560012, India.
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5
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Bi M, Su W, Li J, Mo X. Insights into the inhibition of protospacer integration via direct interaction between Cas2 and AcrVA5. Nat Commun 2024; 15:3256. [PMID: 38627399 PMCID: PMC11021501 DOI: 10.1038/s41467-024-47713-7] [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: 04/13/2023] [Accepted: 04/10/2024] [Indexed: 04/19/2024] Open
Abstract
Spacer acquisition step in CRISPR-Cas system involves the recognition and subsequent integration of protospacer by the Cas1-Cas2 complex in CRISPR-Cas systems. Here we report an anti-CRISPR protein, AcrVA5, and reveal the mechanisms by which it strongly inhibits protospacer integration. Our biochemical data shows that the integration by Cas1-Cas2 was abrogated in the presence of AcrVA5. AcrVA5 exhibits low binding affinity towards Cas2 and acetylates Cas2 at Lys55 on the binding interface of the Cas2 and AcrVA5 N-terminal peptide complex to inhibit the Cas2-mediated endonuclease activity. Moreover, a detailed structural comparison between our crystal structure and homolog structure shows that binding of AcrVA5 to Cas2 causes steric hindrance to the neighboring protospacer resulting in the partial disassembly of the Cas1-Cas2 and protospacer complex, as demonstrated by electrophoretic mobility shift assay. Our study focuses on this mechanism of spacer acquisition inhibition and provides insights into the biology of CRISPR-Cas systems.
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Affiliation(s)
- Mingfang Bi
- College of Veterinary Medicine, Jilin University, 130062, Changchun, Jilin, China
| | - Wenjing Su
- College of Veterinary Medicine, Jilin University, 130062, Changchun, Jilin, China
| | - Jiafu Li
- College of Veterinary Medicine, Jilin University, 130062, Changchun, Jilin, China
| | - Xiaobing Mo
- College of Veterinary Medicine, Jilin University, 130062, Changchun, Jilin, China.
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, Jilin University, 130062, Changchun, Jilin, China.
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6
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López-Beltrán A, Botelho J, Iranzo J. Dynamics of CRISPR-mediated virus-host interactions in the human gut microbiome. THE ISME JOURNAL 2024; 18:wrae134. [PMID: 39023219 PMCID: PMC11307328 DOI: 10.1093/ismejo/wrae134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 06/07/2024] [Accepted: 07/17/2024] [Indexed: 07/20/2024]
Abstract
Arms races between mobile genetic elements and prokaryotic hosts are major drivers of ecological and evolutionary change in microbial communities. Prokaryotic defense systems such as CRISPR-Cas have the potential to regulate microbiome composition by modifying the interactions among bacteria, plasmids, and phages. Here, we used longitudinal metagenomic data from 130 healthy and diseased individuals to study how the interplay of genetic parasites and CRISPR-Cas immunity reflects on the dynamics and composition of the human gut microbiome. Based on the coordinated study of 80 000 CRISPR-Cas loci and their targets, we show that CRISPR-Cas immunity effectively modulates bacteriophage abundances in the gut. Acquisition of CRISPR-Cas immunity typically leads to a decrease in the abundance of lytic phages but does not necessarily cause their complete disappearance. Much smaller effects are observed for lysogenic phages and plasmids. Conversely, phage-CRISPR interactions shape bacterial microdiversity by producing weak selective sweeps that benefit immune host lineages. We also show that distal (and chronologically older) regions of CRISPR arrays are enriched in spacers that are potentially functional and target crass-like phages and local prophages. This suggests that exposure to reactivated prophages and other endemic viruses is a major selective pressure in the gut microbiome that drives the maintenance of long-lasting immune memory.
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Affiliation(s)
- Adrián López-Beltrán
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Parque Científico y Tecnológico UPM, Campus de Montegancedo, 28223, Madrid, Spain
| | - João Botelho
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Parque Científico y Tecnológico UPM, Campus de Montegancedo, 28223, Madrid, Spain
| | - Jaime Iranzo
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Torrejón a Ajalvir Km 4, 28850, Torrejón de Ardoz, Madrid, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Campus Río Ebro, 50018, Zaragoza, Spain
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7
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Santiago-Frangos A, Henriques WS, Wiegand T, Gauvin CC, Buyukyoruk M, Graham AB, Wilkinson RA, Triem L, Neselu K, Eng ET, Lander GC, Wiedenheft B. Structure reveals why genome folding is necessary for site-specific integration of foreign DNA into CRISPR arrays. Nat Struct Mol Biol 2023; 30:1675-1685. [PMID: 37710013 PMCID: PMC10872659 DOI: 10.1038/s41594-023-01097-2] [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: 03/22/2023] [Accepted: 08/15/2023] [Indexed: 09/16/2023]
Abstract
Bacteria and archaea acquire resistance to viruses and plasmids by integrating fragments of foreign DNA into the first repeat of a CRISPR array. However, the mechanism of site-specific integration remains poorly understood. Here, we determine a 560-kDa integration complex structure that explains how Pseudomonas aeruginosa Cas (Cas1-Cas2/3) and non-Cas proteins (for example, integration host factor) fold 150 base pairs of host DNA into a U-shaped bend and a loop that protrude from Cas1-2/3 at right angles. The U-shaped bend traps foreign DNA on one face of the Cas1-2/3 integrase, while the loop places the first CRISPR repeat in the Cas1 active site. Both Cas3 proteins rotate 100 degrees to expose DNA-binding sites on either side of the Cas2 homodimer, which each bind an inverted repeat motif in the leader. Leader sequence motifs direct Cas1-2/3-mediated integration to diverse repeat sequences that have a 5'-GT. Collectively, this work reveals new DNA-binding surfaces on Cas2 that are critical for DNA folding and site-specific delivery of foreign DNA.
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Affiliation(s)
| | - William S Henriques
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Tanner Wiegand
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Colin C Gauvin
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
- Thermal Biology Institute, Montana State University, Bozeman, MT, USA
| | - Murat Buyukyoruk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Ava B Graham
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Royce A Wilkinson
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Lenny Triem
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Kasahun Neselu
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, New York, NY, USA
| | - Edward T Eng
- Simons Electron Microscopy Center, National Resource for Automated Molecular Microscopy, New York Structural Biology Center, New York, NY, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
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8
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Watts EA, Garrett SC, Catchpole RJ, Clark LM, Sanders TJ, Marshall CJ, Wenck BR, Vickerman RL, Santangelo TJ, Fuchs R, Robb B, Olson S, Graveley BR, Terns MP. Histones direct site-specific CRISPR spacer acquisition in model archaeon. Nat Microbiol 2023; 8:1682-1694. [PMID: 37550505 PMCID: PMC10823912 DOI: 10.1038/s41564-023-01446-3] [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: 10/27/2022] [Accepted: 07/11/2023] [Indexed: 08/09/2023]
Abstract
CRISPR-Cas systems provide heritable immunity against viruses and other mobile genetic elements by incorporating fragments of invader DNA into the host CRISPR array as spacers. Integration of new spacers is localized to the 5' end of the array, and in certain Gram-negative Bacteria this polarized localization is accomplished by the integration host factor. For most other Bacteria and Archaea, the mechanism for 5' end localization is unknown. Here we show that archaeal histones play a key role in directing integration of CRISPR spacers. In Pyrococcus furiosus, deletion of either histone A or B impairs integration. In vitro, purified histones are sufficient to direct integration to the 5' end of the CRISPR array. Archaeal histone tetramers and bacterial integration host factor induce similar U-turn bends in bound DNA. These findings indicate a co-evolution of CRISPR arrays with chromosomal DNA binding proteins and a widespread role for binding and bending of DNA to facilitate accurate spacer integration.
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9
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Mikkelsen K, Bowring JZ, Ng YK, Svanberg Frisinger F, Maglegaard JK, Li Q, Sieber RN, Petersen A, Andersen PS, Rostøl JT, Høyland-Kroghsbo NM, Ingmer H. An Endogenous Staphylococcus aureus CRISPR-Cas System Limits Phage Proliferation and Is Efficiently Excised from the Genome as Part of the SCC mec Cassette. Microbiol Spectr 2023; 11:e0127723. [PMID: 37404143 PMCID: PMC10434264 DOI: 10.1128/spectrum.01277-23] [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: 03/28/2023] [Accepted: 06/11/2023] [Indexed: 07/06/2023] Open
Abstract
CRISPR-Cas is an adaptive immune system that allows bacteria to inactivate mobile genetic elements. Approximately 50% of bacteria harbor CRISPR-Cas; however, in the human pathogen Staphylococcus aureus, CRISPR-Cas loci are less common and often studied in heterologous systems. We analyzed the prevalence of CRISPR-Cas in genomes of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in Denmark. Only 2.9% of the strains carried CRISPR-Cas systems, but for strains of sequence type ST630, over half were positive. All CRISPR-Cas loci were type III-A and located within the staphylococcal cassette chromosome mec (SCCmec) type V(5C2&5), conferring β-lactam resistance. Curiously, only 23 different CRISPR spacers were identified in 69 CRISPR-Cas positive strains, and almost identical SCCmec cassettes, CRISPR arrays, and cas genes are present in staphylococcal species other than S. aureus, suggesting that these were transferred horizontally. For the ST630 strain 110900, we demonstrate that the SCCmec cassette containing CRISPR-Cas is excised from the chromosome at high frequency. However, the cassette was not transferable under the conditions investigated. One of the CRISPR spacers targets a late gene in the lytic bacteriophage phiIPLA-RODI, and we show that the system protects against phage infection by reducing phage burst size. However, CRISPR-Cas can be overloaded or circumvented by CRISPR escape mutants. Our results imply that the endogenous type III-A CRISPR-Cas system in S. aureus is active against targeted phages, albeit with low efficacy. This suggests that native S. aureus CRISPR-Cas offers only partial immunity and in nature may work in tandem with other defense systems. IMPORTANCE CRISPR-Cas is an adaptive immune system protecting bacteria and archaea against mobile genetic elements such as phages. In strains of Staphylococcus aureus, CRISPR-Cas is rare, but when present, it is located within the SCCmec element, which encodes resistance to methicillin and other β-lactam antibiotics. We show that the element is excisable, suggesting that the CRISPR-Cas locus is transferable. In support of this, we found almost identical CRISPR-Cas-carrying SCCmec elements in different species of non-S. aureus staphylococci, indicating that the system is mobile but only rarely acquires new spacers in S. aureus. Additionally, we show that in its endogenous form, the S. aureus CRISPR-Cas is active but inefficient against lytic phages that can overload the system or form escape mutants. Thus, we propose that CRISPR-Cas in S. aureus offers only partial immunity in native systems and so may work with other defense systems to prevent phage-mediated killing.
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Affiliation(s)
- Kasper Mikkelsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Janine Zara Bowring
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yong Kai Ng
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | | | | | - Qiuchun Li
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Raphael N. Sieber
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Andreas Petersen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Paal Skytt Andersen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Jakob T. Rostøl
- Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Nina Molin Høyland-Kroghsbo
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Kenney CT, Marraffini LA. Rarely acquired type II-A CRISPR-Cas spacers mediate anti-viral immunity through the targeting of a non-canonical PAM sequence. Nucleic Acids Res 2023; 51:7438-7450. [PMID: 37293964 PMCID: PMC10415147 DOI: 10.1093/nar/gkad501] [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: 12/23/2022] [Revised: 05/23/2023] [Accepted: 06/07/2023] [Indexed: 06/10/2023] Open
Abstract
The Streptococcus pyogenes type II-A CRISPR-Cas systems provides adaptive immunity through the acquisition of short DNA sequences from invading viral genomes, called spacers. Spacers are transcribed into short RNA guides that match regions of the viral genome followed by a conserved NGG DNA motif, known as the PAM. These RNA guides, in turn, are used by the Cas9 nuclease to find and destroy complementary DNA targets within the viral genome. While most of the spacers present in bacterial populations that survive phage infection target protospacers flanked by NGG sequences, there is a small fraction that target non-canonical PAMs. Whether these spacers originate through accidental acquisition of phage sequences and/or provide efficient defense is unknown. Here we found that many of them match phage target regions flanked by an NAGG PAM. Despite being scarcely present in bacterial populations, NAGG spacers provide substantial immunity in vivo and generate RNA guides that support robust DNA cleavage by Cas9 in vitro; with both activities comparable to spacers that target sequences followed by the canonical AGG PAM. In contrast, acquisition experiments showed that NAGG spacers are acquired at very low frequencies. We therefore conclude that discrimination against these sequences occurs during immunization of the host. Our results reveal unexpected differences in PAM recognition during the spacer acquisition and targeting stages of the type II-A CRISPR-Cas immune response.
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Affiliation(s)
- Claire T Kenney
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA
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11
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Amundson KK, Roux S, Shelton JL, Wilkins MJ. Long-term CRISPR locus dynamics and stable host-virus co-existence in subsurface fractured shales. Curr Biol 2023; 33:3125-3135.e4. [PMID: 37402375 DOI: 10.1016/j.cub.2023.06.033] [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: 03/08/2023] [Revised: 05/18/2023] [Accepted: 06/12/2023] [Indexed: 07/06/2023]
Abstract
Viruses are the most ubiquitous biological entities on Earth. Even so, elucidating the impact of viruses on microbial communities and associated ecosystem processes often requires identification of unambiguous host-virus linkages-an undeniable challenge in many ecosystems. Subsurface fractured shales present a unique opportunity to first make these strong linkages via spacers in CRISPR-Cas arrays and subsequently reveal complex long-term host-virus dynamics. Here, we sampled two replicated sets of fractured shale wells for nearly 800 days, resulting in 78 metagenomes from temporal sampling of six wells in the Denver-Julesburg Basin (Colorado, USA). At the community level, there was strong evidence for CRISPR-Cas defense systems being used through time and likely in response to viral interactions. Within our host genomes, represented by 202 unique MAGs, we also saw that CRISPR-Cas systems were widely encoded. Together, spacers from host CRISPR loci facilitated 2,110 CRISPR-based viral linkages across 90 host MAGs spanning 25 phyla. We observed less redundancy in host-viral linkages and fewer spacers associated with hosts from the older, more established wells, possibly reflecting enrichment of more beneficial spacers through time. Leveraging temporal patterns of host-virus linkages across differing well ages, we report how host-virus co-existence dynamics develop and converge through time, possibly reflecting selection for viruses that can evade host CRISPR-Cas systems. Together, our findings shed light on the complexities of host-virus interactions as well as long-term dynamics of CRISPR-Cas defense among diverse microbial populations.
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Affiliation(s)
- Kaela K Amundson
- Colorado State University, Department of Soil & Crop Sciences, 301 University Ave., Fort Collins, CO 80523, USA.
| | - Simon Roux
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Jenna L Shelton
- United States Geological Survey, 12201 Sunrise Valley Dr., Reston, VA 20192, USA
| | - Michael J Wilkins
- Colorado State University, Department of Soil & Crop Sciences, 301 University Ave., Fort Collins, CO 80523, USA
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12
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Collins AJ, Whitaker RJ. CRISPR Comparison Toolkit: Rapid Identification, Visualization, and Analysis of CRISPR Array Diversity. CRISPR J 2023; 6:386-400. [PMID: 37459160 PMCID: PMC10457644 DOI: 10.1089/crispr.2022.0080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 05/23/2023] [Indexed: 08/19/2023] Open
Abstract
CRISPR-Cas systems provide immunity against mobile genetic elements (MGEs) through sequence-specific targeting by spacer sequences encoded in CRISPR arrays. Spacers are highly variable between microbial strains and can be acquired rapidly, making them well suited for use in strain typing of closely related organisms. However, no tools are currently available to automate the process of reconstructing strain histories using CRISPR spacers. We therefore developed the CRISPR Comparison Toolkit (CCTK) to enable analyses of array relationships. The CCTK includes tools to identify arrays, analyze relationships between arrays using CRISPRdiff and CRISPRtree, and predict targets of spacers. CRISPRdiff visualizes arrays and highlights the similarities between them. CRISPRtree infers a phylogenetic tree from array relationships and presents a hypothesis of the evolutionary history of the arrays. The CCTK unifies several CRISPR analysis tools into a single command line application, including the first tool to infer phylogenies from array relationships.
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Affiliation(s)
- Alan J. Collins
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA and University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Rachel J. Whitaker
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA and University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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13
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Silva AMA, Luz ACO, Xavier KVM, Barros MPS, Alves HB, Batista MVA, Leal-Balbino TC. Analysis of CRISPR/Cas Genetic Structure, Spacer Content and Molecular Epidemiology in Brazilian Acinetobacter baumannii Clinical Isolates. Pathogens 2023; 12:764. [PMID: 37375454 DOI: 10.3390/pathogens12060764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/08/2023] [Accepted: 05/11/2023] [Indexed: 06/29/2023] Open
Abstract
CRISPR/Cas is a molecular mechanism to prevent predatory viruses from invading bacteria via the insertion of small viral sequences (spacers) in its repetitive locus. The nature of spacer incorporation and the viral origins of spacers provide an overview of the genetic evolution of bacteria, their natural viral predators, and the mechanisms that prokaryotes may use to protect themselves, or to acquire mobile genetic elements such as plasmids. Here, we report on the CRISPR/Cas genetic structure, its spacer content, and strain epidemiology through MLST and CRISPR typing in Acinetobacter baumannii, an opportunistic pathogen intimately related to hospital infections and antimicrobial resistance. Results show distinct genetic characteristics, such as polymorphisms specific to ancestor direct repeats, a well-defined degenerate repeat, and a conserved leader sequence, as well as showing most spacers as targeting bacteriophages, and several self-targeting spacers, directed at prophages. There was a particular relationship between CRISPR/Cas and CC113 in the study of Brazilian isolates, and CRISPR-related typing techniques are interesting for subtyping strains with the same MLST profile. We want to emphasize the significance of descriptive genetic research on CRISPR loci, and we argue that spacer or CRISPR typing are helpful for small-scale investigations, preferably in conjunction with other molecular typing techniques such as MLST.
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Affiliation(s)
- Adrianne M A Silva
- Departamento de Microbiologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife CEP 50740-465, Pernambuco, Brazil
| | - Ana C O Luz
- Departamento de Microbiologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife CEP 50740-465, Pernambuco, Brazil
| | - Keyla V M Xavier
- Departamento de Microbiologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife CEP 50740-465, Pernambuco, Brazil
| | - Maria P S Barros
- Laboratório de Bioprocessos, Centro de Tecnologias Estratégicas do Nordeste, Recife CEP 50740-545, Pernambuco, Brazil
| | - Hirisleide B Alves
- Departamento de Microbiologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife CEP 50740-465, Pernambuco, Brazil
| | - Marcus V A Batista
- Laboratório de Genética Molecular e Biotecnologia, Centro de Ciências Biológicas e da Saúde-CCBS, Universidade Federal de Sergipe, Aracaju CEP 49060-108, Sergipe, Brazil
| | - Tereza C Leal-Balbino
- Departamento de Microbiologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife CEP 50740-465, Pernambuco, Brazil
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14
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Rasmussen TS, Koefoed AK, Deng L, Muhammed MK, Rousseau GM, Kot W, Sprotte S, Neve H, Franz CMAP, Hansen AK, Vogensen FK, Moineau S, Nielsen DS. CRISPR-Cas provides limited phage immunity to a prevalent gut bacterium in gnotobiotic mice. THE ISME JOURNAL 2023; 17:432-442. [PMID: 36631688 PMCID: PMC9938214 DOI: 10.1038/s41396-023-01358-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023]
Abstract
Many bacteria and archaea harbor the adaptive CRISPR-Cas system, which stores small nucleotide fragments from previous invasions of nucleic acids via viruses or plasmids. This molecular archive blocks further invaders carrying identical or similar nucleotide sequences. However, few of these systems have been confirmed experimentally to be active in gut bacteria. Here, we demonstrate experimentally that the type I-C CRISPR-Cas system of the prevalent gut bacterium Eggerthella lenta can specifically target and cleave foreign DNA in vitro by using a plasmid transformation assay. We also show that the CRISPR-Cas system acquires new immunities (spacers) from the genome of a virulent E. lenta phage using traditional phage assays in vitro but also in vivo using gnotobiotic (GB) mice. Both high phage titer and an increased number of spacer acquisition events were observed when E. lenta was exposed to a low multiplicity of infection in vitro, and three phage genes were found to contain protospacer hotspots. Fewer new spacer acquisitions were detected in vivo than in vitro. Longitudinal analysis of phage-bacteria interactions showed sustained coexistence in the gut of GB mice, with phage abundance being approximately one log higher than the bacteria. Our findings show that while the type I-C CRISPR-Cas system is active in vitro and in vivo, a highly virulent phage in vitro was still able to co-exist with its bacterial host in vivo. Taken altogether, our results suggest that the CRISPR-Cas defense system of E. lenta provides only partial immunity in the gut.
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Affiliation(s)
- Torben Sølbeck Rasmussen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark.
| | - Anna Kirstine Koefoed
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Ling Deng
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Musemma K Muhammed
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Geneviève M Rousseau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de 1enie, Université Laval, Québec, QC, G1V 0A6, Canada
- Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Witold Kot
- Section of Microbial Ecology and Biotechnology, Department of Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg, Denmark
| | - Sabrina Sprotte
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Charles M A P Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103, Kiel, Germany
| | - Axel Kornerup Hansen
- Section of Experimental Animal Models, Department of Veterinary and Animal Sciences, University of Copenhagen, 1871, Frederiksberg, Denmark
| | - Finn Kvist Vogensen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark
| | - Sylvain Moineau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de 1enie, Université Laval, Québec, QC, G1V 0A6, Canada
- Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
- Félix d'Hérelle Reference Center for Bacterial Viruses, Faculté de médecine dentaire, Université Laval, Québec, QC, G1V 0A6, Canada
| | - Dennis Sandris Nielsen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of Science, University of Copenhagen, 1958, Frederiksberg, Denmark.
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15
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Flusche T, Rajan R. Molecular Details of DNA Integration by CRISPR-Associated Proteins During Adaptation in Bacteria and Archaea. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1414:27-43. [PMID: 35852729 DOI: 10.1007/5584_2022_730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins constitute an adaptive immune system in bacteria and archaea, where immunological memory is retained in the CRISPR locus as short pieces of the intruding nucleic acid, termed spacers. The adaptation to new infections occurs through the integration of a new spacer into the CRISPR array. For immune protection, spacers are transcribed into CRISPR RNAs (crRNA) that are used to guide the effector nuclease of the system in sequence-dependent target cleavage. Spacers originate as a prespacer from either DNA or RNA depending on the CRISPR-Cas system being observed, and the nearly universal Cas proteins, Cas1 and Cas2, insert the prespacer into the CRISPR locus during adaptation in all systems that contain them. The mechanism of site-specific prespacer integration varies across CRISPR classes and types, and distinct differences can even be found within the same subtype. In this review, the current knowledge on the mechanisms of prespacer integration in type II-A CRISPR-Cas systems will be described. Comparisons of the currently characterized type II-A systems show that distinct mechanisms exist within different members of this subtype and are correlated to sequence-specific interactions of Cas proteins and the DNA elements present in the CRISPR array. These observations indicate that nature has fine-tuned the mechanistic details while performing the basic step of DNA integration by Cas proteins, which offers unique advantages to develop Cas1-Cas2-based biotechnology.
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Affiliation(s)
- Tamara Flusche
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, USA
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK, USA.
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16
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A pyrF-Based Efficient Genetic Manipulation Platform in Acinetobacter baumannii To Explore the Vital DNA Components of Adaptive Immunity for I-F CRISPR-Cas. Microbiol Spectr 2022; 10:e0195722. [PMID: 36047802 PMCID: PMC9602844 DOI: 10.1128/spectrum.01957-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii is an important pathogenic bacterium with multidrug resistance which causes infections with high mortality rates. In-depth genetic analysis of A. baumannii virulence and drug-resistant genes is highly desirable. In this study, we utilized the conserved pyrF-flanking fragment to rapidly generate uracil auxotrophy hosts with pyrF deleted in model and clinical A. baumannii strains and then introduced the pyrF gene as the selectable and counterselectable marker to establish a series of gene manipulation vectors. For gene deletion with the suicide pyrF-based plasmid, the second-crossover colonies screened with the pyrF/5-fluoroorotic acid (5-FOA) system were obtained more quickly and efficiently than those screened with the sacB/sucrose system. By using the replicative plasmid, the recognized protospacer-adjacent motif (PAM) bias for type I-F CRISPR was experimentally revealed in A. baumannii AYE. Interestingly, interference recognized only the PAM-CC sequence, whereas adaptation priming tolerates 4 PAM sequences. Furthermore, we also performed a rapid and extensive modification of the I-F CRISPR-Cas elements and revealed that the role of double-nucleotide sequence mutants at the end of the repeat could be critical during both CRISPR interference and priming; we also found strong biases for A and demonstrated that adaptation could tolerate certain sequence and size variations of the leader in A. baumannii. In conclusion, this pyrF-based genetic manipulation system was readily applicable and efficient for exploring the genetic characteristics of A. baumannii. IMPORTANCE In this study, we developed the widely applicable and efficient pyrF-based selection and counterselection system in A. baumannii for gene manipulation. In most cases, this pyrF/5-FOA genetic manipulation system was very effective and enabled us to obtain marker-free mutants in a very short period of time. Utilizing this system and the separate mechanism of interference and/or primed adaptation, our experiments revealed some recognition mechanism differences for the key DNA elements of PAM, leader, and repeat in the priming adaptation process of the I-F CRISPR-Cas systems of A. baumannii, which provided some new and original insights for the study of the molecular mechanisms of these processes and laid a foundation for further studies.
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17
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DNA Motifs and an Accessory CRISPR Factor Determine Cas1 Binding and Integration Activity in Sulfolobus islandicus. Int J Mol Sci 2022; 23:ijms231710178. [PMID: 36077578 PMCID: PMC9456107 DOI: 10.3390/ijms231710178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
CRISPR-Cas systems empower prokaryotes with adaptive immunity against invasive mobile genetic elements. At the first step of CRISPR immunity adaptation, short DNA fragments from the invaders are integrated into CRISPR arrays at the leader-proximal end. To date, the mechanism of recognition of the leader-proximal end remains largely unknown. Here, in the Sulfolobus islandicus subtype I-A system, we show that mutations destroying the proximal region reduce CRISPR adaptation in vivo. We identify that a stem-loop structure is present on the leader-proximal end, and we demonstrate that Cas1 preferentially binds the stem-loop structure in vitro. Moreover, we demonstrate that the integrase activity of Cas1 is modulated by interacting with a CRISPR-associated factor Csa3a. When translocated to the CRISPR array, the Csa3a-Cas1 complex is separated by Csa3a binding to the leader-distal motif and Cas1 binding to the leader-proximal end. Mutation at the leader-distal motif reduces CRISPR adaptation efficiency, further confirming the in vivo function of leader-distal motif. Together, our results suggest a general model for binding of Cas1 protein to a leader motif and modulation of integrase activity by an accessory factor.
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18
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Lam TJ, Mortensen K, Ye Y. Diversity and dynamics of the CRISPR-Cas systems associated with Bacteroides fragilis in human population. BMC Genomics 2022; 23:573. [PMID: 35953824 PMCID: PMC9367070 DOI: 10.1186/s12864-022-08770-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 07/15/2022] [Indexed: 11/22/2022] Open
Abstract
Background CRISPR-Cas (clustered regularly interspaced short palindromic repeats—CRISPR-associated proteins) systems are adaptive immune systems commonly found in prokaryotes that provide sequence-specific defense against invading mobile genetic elements (MGEs). The memory of these immunological encounters are stored in CRISPR arrays, where spacer sequences record the identity and history of past invaders. Analyzing such CRISPR arrays provide insights into the dynamics of CRISPR-Cas systems and the adaptation of their host bacteria to rapidly changing environments such as the human gut. Results In this study, we utilized 601 publicly available Bacteroides fragilis genome isolates from 12 healthy individuals, 6 of which include longitudinal observations, and 222 available B. fragilis reference genomes to update the understanding of B. fragilis CRISPR-Cas dynamics and their differential activities. Analysis of longitudinal genomic data showed that some CRISPR array structures remained relatively stable over time whereas others involved radical spacer acquisition during some periods, and diverse CRISPR arrays (associated with multiple isolates) co-existed in the same individuals with some persisted over time. Furthermore, features of CRISPR adaptation, evolution, and microdynamics were highlighted through an analysis of host-MGE network, such as modules of multiple MGEs and hosts, reflecting complex interactions between B. fragilis and its invaders mediated through the CRISPR-Cas systems. Conclusions We made available of all annotated CRISPR-Cas systems and their target MGEs, and their interaction network as a web resource at https://omics.informatics.indiana.edu/CRISPRone/Bfragilis. We anticipate it will become an important resource for studying of B. fragilis, its CRISPR-Cas systems, and its interaction with mobile genetic elements providing insights into evolutionary dynamics that may shape the species virulence and lead to its pathogenicity. Supplementary Information The online version contains supplementary material available at (10.1186/s12864-022-08770-8).
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Affiliation(s)
- Tony J Lam
- School of Informatics, Computing and Engineering, Indiana University, Bloomington, IN, USA
| | - Kate Mortensen
- School of Informatics, Computing and Engineering, Indiana University, Bloomington, IN, USA
| | - Yuzhen Ye
- School of Informatics, Computing and Engineering, Indiana University, Bloomington, IN, USA.
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19
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Spacer prioritization in CRISPR-Cas9 immunity is enabled by the leader RNA. Nat Microbiol 2022; 7:530-541. [PMID: 35314780 PMCID: PMC7612570 DOI: 10.1038/s41564-022-01074-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 02/01/2022] [Indexed: 11/08/2022]
Abstract
CRISPR-Cas systems store fragments of foreign DNA called spacers as immunological recordings used to combat future infections. Of the many spacers stored in a CRISPR array, the newest spacers are known to be prioritized for immune defense. However, the underlying mechanism remains unclear. Here we show that the leader region upstream of CRISPR arrays in CRISPR-Cas9 systems enhances CRISPR RNA (crRNA) processing from the newest spacer, prioritizing defense against the matching invader. Using the CRISPR-Cas9 system from Streptococcus pyogenes as a model, we found that the transcribed leader interacts with the conserved repeats bordering the newest spacer. The resulting interaction promotes tracrRNA hybridization with the second repeat, accelerating crRNA processing. Accordingly, disrupting this structure reduces the abundance of the associated crRNA and immune defense against targeted plasmids and bacteriophages. Beyond the S. pyogenes system, bioinformatics analyses revealed that leader-repeat structures appear across CRISPR-Cas9 systems. CRISPR-Cas systems thus possess an RNA-based mechanism to prioritize defense against the most recently encountered invaders.
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20
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Lee H, Sashital DG. Creating memories: molecular mechanisms of CRISPR adaptation. Trends Biochem Sci 2022; 47:464-476. [DOI: 10.1016/j.tibs.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/22/2022]
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21
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Fordjour E, Mensah EO, Hao Y, Yang Y, Liu X, Li Y, Liu CL, Bai Z. Toward improved terpenoids biosynthesis: strategies to enhance the capabilities of cell factories. BIORESOUR BIOPROCESS 2022; 9:6. [PMID: 38647812 PMCID: PMC10992668 DOI: 10.1186/s40643-022-00493-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/04/2022] [Indexed: 02/22/2023] Open
Abstract
Terpenoids form the most diversified class of natural products, which have gained application in the pharmaceutical, food, transportation, and fine and bulk chemical industries. Extraction from naturally occurring sources does not meet industrial demands, whereas chemical synthesis is often associated with poor enantio-selectivity, harsh working conditions, and environmental pollutions. Microbial cell factories come as a suitable replacement. However, designing efficient microbial platforms for isoprenoid synthesis is often a challenging task. This has to do with the cytotoxic effects of pathway intermediates and some end products, instability of expressed pathways, as well as high enzyme promiscuity. Also, the low enzymatic activity of some terpene synthases and prenyltransferases, and the lack of an efficient throughput system to screen improved high-performing strains are bottlenecks in strain development. Metabolic engineering and synthetic biology seek to overcome these issues through the provision of effective synthetic tools. This review sought to provide an in-depth description of novel strategies for improving cell factory performance. We focused on improving transcriptional and translational efficiencies through static and dynamic regulatory elements, enzyme engineering and high-throughput screening strategies, cellular function enhancement through chromosomal integration, metabolite tolerance, and modularization of pathways.
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Affiliation(s)
- Eric Fordjour
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Emmanuel Osei Mensah
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Yunpeng Hao
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Yankun Yang
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Xiuxia Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Ye Li
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China
| | - Chun-Li Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China.
| | - Zhonghu Bai
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Jiangsu Provincial Research Centre for Bioactive Product Processing Technology, Jiangnan University, Wuxi, China.
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22
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Pursey E, Dimitriu T, Paganelli FL, Westra ER, van Houte S. CRISPR-Cas is associated with fewer antibiotic resistance genes in bacterial pathogens. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200464. [PMID: 34839714 PMCID: PMC8628084 DOI: 10.1098/rstb.2020.0464] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/21/2021] [Indexed: 01/19/2023] Open
Abstract
The acquisition of antibiotic resistance (ABR) genes via horizontal gene transfer (HGT) is a key driver of the rise in multidrug resistance amongst bacterial pathogens. Bacterial defence systems per definition restrict the influx of foreign genetic material, and may therefore limit the acquisition of ABR. CRISPR-Cas adaptive immune systems are one of the most prevalent defences in bacteria, found in roughly half of bacterial genomes, but it has remained unclear if and how much they contribute to restricting the spread of ABR. We analysed approximately 40 000 whole genomes comprising the full RefSeq dataset for 11 species of clinically important genera of human pathogens, including Enterococcus, Staphylococcus, Acinetobacter and Pseudomonas. We modelled the association between CRISPR-Cas and indicators of HGT, and found that pathogens with a CRISPR-Cas system were less likely to carry ABR genes than those lacking this defence system. Analysis of the mobile genetic elements (MGEs) targeted by CRISPR-Cas supports a model where this host defence system blocks important vectors of ABR. These results suggest a potential 'immunocompromised' state for multidrug-resistant strains that may be exploited in tailored interventions that rely on MGEs, such as phages or phagemids, to treat infections caused by bacterial pathogens. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
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Affiliation(s)
- Elizabeth Pursey
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Tatiana Dimitriu
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Fernanda L. Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Edze R. Westra
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
| | - Stineke van Houte
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, Cornwall, UK
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23
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Bui LM, Thi Thu Phung H, Ho Thi TT, Singh V, Maurya R, Khambhati K, Wu CC, Uddin MJ, Trung DM, Chu DT. Recent findings and applications of biomedical engineering for COVID-19 diagnosis: a critical review. Bioengineered 2021; 12:8594-8613. [PMID: 34607509 PMCID: PMC8806999 DOI: 10.1080/21655979.2021.1987821] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/28/2021] [Indexed: 12/23/2022] Open
Abstract
COVID-19 is one of the most severe global health crises that humanity has ever faced. Researchers have restlessly focused on developing solutions for monitoring and tracing the viral culprit, SARS-CoV-2, as vital steps to break the chain of infection. Even though biomedical engineering (BME) is considered a rising field of medical sciences, it has demonstrated its pivotal role in nurturing the maturation of COVID-19 diagnostic technologies. Within a very short period of time, BME research applied to COVID-19 diagnosis has advanced with ever-increasing knowledge and inventions, especially in adapting available virus detection technologies into clinical practice and exploiting the power of interdisciplinary research to design novel diagnostic tools or improve the detection efficiency. To assist the development of BME in COVID-19 diagnosis, this review highlights the most recent diagnostic approaches and evaluates the potential of each research direction in the context of the pandemic.
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Affiliation(s)
- Le Minh Bui
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
- Department of Biology, Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Huong Thi Thu Phung
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
| | - Thuy-Tien Ho Thi
- Center for Biomedicine and Community Health, International School, Vietnam National University, Hanoi, Vietnam
| | - Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Mehsana, Gujarat, India
| | - Rupesh Maurya
- Department of Biosciences, School of Science, Indrashil University, Mehsana, Gujarat, India
| | - Khushal Khambhati
- Department of Biosciences, School of Science, Indrashil University, Mehsana, Gujarat, India
| | - Chia-Ching Wu
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Md Jamal Uddin
- ABEx Bio-Research Center, East Azampur, Dhaka, Bangladesh
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea
| | - Do Minh Trung
- Institute of Biomedicine and Pharmacy, Vietnam Military Medical University, Hanoi, Vietnam
| | - Dinh Toi Chu
- Center for Biomedicine and Community Health, International School, Vietnam National University, Hanoi, Vietnam
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Prophage integration into CRISPR loci enables evasion of antiviral immunity in Streptococcus pyogenes. Nat Microbiol 2021; 6:1516-1525. [PMID: 34819640 DOI: 10.1038/s41564-021-00996-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022]
Abstract
CRISPR loci are composed of short DNA repeats separated by sequences, known as spacers, that match the genomes of invaders such as phages and plasmids. Spacers are transcribed and processed to generate RNA guides used by CRISPR-associated nucleases to recognize and destroy the complementary nucleic acids of invaders. To counteract this defence, phages can produce small proteins that inhibit these nucleases, termed anti-CRISPRs (Acrs). Here we demonstrate that the ΦAP1.1 temperate phage utilizes an alternative approach to antagonize the type II-A CRISPR response in Streptococcus pyogenes. Immediately after infection, this phage expresses a small anti-CRISPR protein, AcrIIA23, that prevents Cas9 function, allowing ΦAP1.1 to integrate into the direct repeats of the CRISPR locus, neutralizing immunity. However, acrIIA23 is not transcribed during lysogeny and phage integration/excision cycles can result in the deletion and/or transduction of spacers, enabling a complex modulation of the type II-A CRISPR immune response. A bioinformatic search identified prophages integrated not only in the CRISPR repeats, but also the cas genes, of diverse bacterial species, suggesting that prophage disruption of the CRISPR-cas locus is a recurrent mechanism to counteract immunity.
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25
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Li Y, Mikkelsen K, Lluch I Grané O, Wang Z, Tang Y, Jiao X, Ingmer H, Høyland-Kroghsbo NM, Li Q. Functional Characterization of Type III-A CRISPR-Cas in a Clinical Human Methicillin-R Staphylococcus aureus Strain. CRISPR J 2021; 4:686-698. [PMID: 34558981 DOI: 10.1089/crispr.2021.0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
CRISPR with its cas genes is an adaptive immune system that protects prokaryotes against foreign genetic elements. The type III-A CRISPR-Cas system is rarely found in Staphylococcus aureus, and little is known about its function in S. aureus. Here, we describe the genome characteristics of the clinical methicillin-resistant S. aureus (MRSA) strain TZ0912, carrying a type III-A CRISPR-Cas system. Phylogenetic analysis of 35 reported CRISPR-Cas-positive S. aureus strains revealed that the CRISPR-Cas system is prevalent in CC8 clones (10/35) and is located in the staphylococcal cassette chromosome mec (SCCmec) V, which confers methicillin resistance. Plasmid transformation and phage infection assays reveal that the type III-A CRISPR-Cas system protects TZ0912 against foreign DNA with sequence homology to the spacers located in the CRISPR array. We observed that the CRISPR-Cas immune system could effectively protect MRSA against phage attacks in both liquid culture and solid medium. In accordance with previous reports, using RNA-seq analysis and plasmid transformation assays, we find that the crRNAs close to the leading sequence of the CRISPR array are more highly expressed and are more effective at directing plasmid elimination compared to the distant spacers. This study established a model for evaluating the efficiency of naive CRISPR-Cas system in MRSA against phage, which could contribute to future research on the function of CRISPR-Cas in clinical MRSA isolates and improve phage therapy against MRSA infections.
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Affiliation(s)
- Yang Li
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark
| | - Kasper Mikkelsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark; University of Copenhagen, Copenhagen, Denmark
| | - Oleguer Lluch I Grané
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark; University of Copenhagen, Copenhagen, Denmark
| | - Zhenyu Wang
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark
| | - Yuanyue Tang
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, P.R. China; and University of Copenhagen, Copenhagen, Denmark
| | - Xinan Jiao
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, P.R. China; and University of Copenhagen, Copenhagen, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark; University of Copenhagen, Copenhagen, Denmark
| | | | - Qiuchun Li
- Jiangsu Key Lab of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China, Yangzhou University, P.R. China; University of Copenhagen, Copenhagen, Denmark.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, P.R. China; and University of Copenhagen, Copenhagen, Denmark
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26
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Santiago-Frangos A, Buyukyoruk M, Wiegand T, Krishna P, Wiedenheft B. Distribution and phasing of sequence motifs that facilitate CRISPR adaptation. Curr Biol 2021; 31:3515-3524.e6. [PMID: 34174210 PMCID: PMC8552246 DOI: 10.1016/j.cub.2021.05.068] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/30/2021] [Accepted: 05/28/2021] [Indexed: 12/11/2022]
Abstract
CRISPR-associated proteins (Cas1 and Cas2) integrate foreign DNA at the "leader" end of CRISPR loci. Several CRISPR leader sequences are reported to contain a binding site for a DNA-bending protein called integration host factor (IHF). IHF-induced DNA bending kinks the leader of type I-E CRISPRs, recruiting an upstream sequence motif that helps dock Cas1-2 onto the first repeat of the CRISPR locus. To determine the prevalence of IHF-directed CRISPR adaptation, we analyzed 15,274 bacterial and archaeal CRISPR leaders. These experiments reveal multiple IHF binding sites and diverse upstream sequence motifs in a subset of the I-C, I-E, I-F, and II-C CRISPR leaders. We identify subtype-specific motifs and show that the phase of these motifs is critical for CRISPR adaptation. Collectively, this work clarifies the prevalence and mechanism(s) of IHF-dependent CRISPR adaptation and suggests that leader sequences and adaptation proteins may coevolve under the selective pressures of foreign genetic elements like plasmids or phages.
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Affiliation(s)
| | - Murat Buyukyoruk
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Tanner Wiegand
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Pushya Krishna
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA.
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27
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Pujato S, Galliani V, Irazoqui JM, Amadío A, Quiberoni A, Mercanti D. Analysis of CRISPR systems of types II-A, I-E and I-C in strains of Lacticaseibacillus. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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28
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Characterization and Analysis of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) in Pandemic and Non-Pandemic Vibrio parahaemolyticus Isolates from Seafood Sources. Microorganisms 2021; 9:microorganisms9061220. [PMID: 34199972 PMCID: PMC8226915 DOI: 10.3390/microorganisms9061220] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 11/17/2022] Open
Abstract
Vibrio parahaemolyticus is one of the significant seafood-borne pathogens causing gastroenteritis in humans. Clustered regularly interspaced short palindromic repeats (CRISPR) are commonly detected in the genomes of V. parahaemolyticus and the polymorphism of CRISPR patterns has been applied as a genetic marker for tracking its evolution. In this work, a total of 15 pandemic and 36 non-pandemic V. parahaemolyticus isolates obtained from seafood between 2000 and 2012 were characterized based on hemolytic activity, antimicrobial susceptibility, and CRISPR elements. The results showed that 15/17 of the V. parahaemolyticus seafood isolates carrying the thermostable direct hemolysin gene (tdh+) were Kanagawa phenomenon (KP) positive. The Multiple Antibiotic Resistance (MAR) index ranged between 0.1 and 0.4, and 45% of the isolates have an MAR index ≥ 0.2. A total of 19 isolates were positive for CRISPR detection, including all tdh+ trh− isolates, two of tdh− trh+, and each of tdh+ trh+ and tdh− trh−. Four spacer types (Sp1 to Sp4) were identified, and CRISPR-positive isolates had at least one type of spacer homolog to the region of Vibrio alginolyticus megaplasmid. It is of interest that a specific CRISPR profile and spacer sequence type was observed with correlations to the hemolysin genotype (tdh/trh). Thus, these provide essential data on the exposure of foreign genetic elements and indicate shared ancestry within different genotypes of V. parahaemolyticus isolates.
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Abstract
Streptococcus mutans strain P42S possesses a type II-A CRISPR-Cas system that protects against phage infection and plasmid transformation. The analysis of 293 bacteriophage-insensitive mutants (BIMs) obtained upon exposure to the virulent phage M102AD revealed the acquisition of 399 unique spacers, including several ectopic spacer acquisitions and a few cases of native spacer deletions. The acquisition of multiple spacers was also observed and appears to be mostly due to priming, which has been rarely reported for type II-A systems. Analyses of the acquired spacers indicated that 88% of them are identical to a region of the phage M102AD genome. The remaining 12% of spacers had mismatches with the phage genome, primarily at the 5′ end of the spacer, leaving the seed sequence at the 3′ end largely intact. When a high multiplicity of infection (MOI) was used in the phage challenge assays, we also observed the emergence of CRISPR BIMs that, in addition to the acquisition of new spacers, displayed a reduced phage adsorption phenotype. While CRISPR-Cas and adsorption resistance work in tandem to protect S. mutans P42S against phage M102AD, nonidentified antiviral mechanisms are also likely at play in this strain. IMPORTANCE Bacteria are under the constant threat of viral predation and have therefore developed several defense mechanisms, including CRISPR-Cas systems. While studies on the mode of action of CRISPR-Cas systems have already provided great insights into phage-bacterium interactions, still more information is needed on the biology of these systems. The additional characterization of the type II-A CRISPR-Cas system of Streptococcus mutans P42S in this study provides novel information on the spacer acquisition step, especially regarding protospacer-adjacent motif (PAM) recognition, multiple-spacer acquisition, and priming.
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30
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Abstract
CRISPR-Cas systems provide bacteria and archaea with adaptive, heritable immunity against their viruses (bacteriophages and phages) and other parasitic genetic elements. CRISPR-Cas systems are highly diverse, and we are only beginning to understand their relative importance in phage defense. In this review, we will discuss when and why CRISPR-Cas immunity against phages evolves, and how this, in turn, selects for the evolution of immune evasion by phages. Finally, we will discuss our current understanding of if, and when, we observe coevolution between CRISPR-Cas systems and phages, and how this may be influenced by the mechanism of CRISPR-Cas immunity.
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31
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Garrett SC. Pruning and Tending Immune Memories: Spacer Dynamics in the CRISPR Array. Front Microbiol 2021; 12:664299. [PMID: 33868219 PMCID: PMC8047081 DOI: 10.3389/fmicb.2021.664299] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/12/2021] [Indexed: 01/22/2023] Open
Abstract
CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated genes) is a type of prokaryotic immune system that is unique in its ability to provide sequence-specific adaptive protection, which can be updated in response to new threats. CRISPR-Cas does this by storing fragments of DNA from invading genetic elements in an array interspersed with short repeats. The CRISPR array can be continuously updated through integration of new DNA fragments (termed spacers) at one end, but over time existing spacers become obsolete. To optimize immunity, spacer uptake, residency, and loss must be regulated. This mini-review summarizes what is known about how spacers are organized, maintained, and lost from CRISPR arrays.
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Affiliation(s)
- Sandra C Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT, United States
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32
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Achigar R, Scarrone M, Rousseau GM, Philippe C, Machado F, Duvós V, Campot MP, Dion MB, Shao Y, Pianzzola MJ, Moineau S. Ectopic Spacer Acquisition in Streptococcus thermophilus CRISPR3 Array. Microorganisms 2021; 9:microorganisms9030512. [PMID: 33804420 PMCID: PMC7999890 DOI: 10.3390/microorganisms9030512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
Streptococcus thermophilus relies heavily on two type II-A CRISPR-Cas systems, CRISPR1 and CRISPR3, to resist siphophage infections. One hallmark of these systems is the integration of a new spacer at the 5' end of the CRISPR arrays following phage infection. However, we have previously shown that ectopic acquisition of spacers can occur within the CRISPR1 array. Here, we present evidence of the acquisition of new spacers within the array of CRISPR3 of S. thermophilus. The analysis of randomly selected bacteriophage-insensitive mutants of the strain Uy01 obtained after phage infection, as well as the comparison with other S. thermophilus strains with similar CRISPR3 content, showed that a specific spacer within the array could be responsible for misguiding the adaptation complex. These results also indicate that while the vast majority of new spacers are added at the 5' end of the CRISPR array, ectopic spacer acquisition is a common feature of both CRISPR1 and CRISPR3 systems in S. thermophilus, and it can still provide phage resistance. Ectopic spacer acquisition also appears to have occurred naturally in some strains of Streptococcus pyogenes, suggesting that it is a general phenomenon, at least in type II-A systems.
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Affiliation(s)
- Rodrigo Achigar
- Laboratorio de Biotecnología, Facultad de Ingeniería, Universidad ORT Uruguay, Montevideo 11100, Uruguay; (R.A.); (F.M.); (V.D.); (M.P.C.)
| | - Martina Scarrone
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
| | - Geneviève M. Rousseau
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
| | - Cécile Philippe
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
| | - Felipe Machado
- Laboratorio de Biotecnología, Facultad de Ingeniería, Universidad ORT Uruguay, Montevideo 11100, Uruguay; (R.A.); (F.M.); (V.D.); (M.P.C.)
| | - Valentina Duvós
- Laboratorio de Biotecnología, Facultad de Ingeniería, Universidad ORT Uruguay, Montevideo 11100, Uruguay; (R.A.); (F.M.); (V.D.); (M.P.C.)
| | - María Pía Campot
- Laboratorio de Biotecnología, Facultad de Ingeniería, Universidad ORT Uruguay, Montevideo 11100, Uruguay; (R.A.); (F.M.); (V.D.); (M.P.C.)
| | - Moïra B. Dion
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
| | - Yuyu Shao
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
| | - María Julia Pianzzola
- Departamento de Biociencias (DEPBIO), Facultad de Química, Universidad de la República, Montevideo 11800, Uruguay;
| | - Sylvain Moineau
- Département de Biochimie, De Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V 0A6, Canada; (M.S.); (G.M.R.); (C.P.); (M.B.D.); (Y.S.)
- Groupe de Recherche en Écologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
- Félix d’Hérelle Reference Center for Bacterial Viruses, Faculté de Médecine Dentaire, Université Laval, Québec, QC G1V 0A6, Canada
- Correspondence: ; Tel.: +1-418-656-3712
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Pavlova YS, Paez-Espino D, Morozov AY, Belalov IS. Searching for fat tails in CRISPR-Cas systems: Data analysis and mathematical modeling. PLoS Comput Biol 2021; 17:e1008841. [PMID: 33770071 PMCID: PMC8026048 DOI: 10.1371/journal.pcbi.1008841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 04/07/2021] [Accepted: 03/01/2021] [Indexed: 12/28/2022] Open
Abstract
Understanding CRISPR-Cas systems-the adaptive defence mechanism that about half of bacterial species and most of archaea use to neutralise viral attacks-is important for explaining the biodiversity observed in the microbial world as well as for editing animal and plant genomes effectively. The CRISPR-Cas system learns from previous viral infections and integrates small pieces from phage genomes called spacers into the microbial genome. The resulting library of spacers collected in CRISPR arrays is then compared with the DNA of potential invaders. One of the most intriguing and least well understood questions about CRISPR-Cas systems is the distribution of spacers across the microbial population. Here, using empirical data, we show that the global distribution of spacer numbers in CRISPR arrays across multiple biomes worldwide typically exhibits scale-invariant power law behaviour, and the standard deviation is greater than the sample mean. We develop a mathematical model of spacer loss and acquisition dynamics which fits observed data from almost four thousand metagenomes well. In analogy to the classical 'rich-get-richer' mechanism of power law emergence, the rate of spacer acquisition is proportional to the CRISPR array size, which allows a small proportion of CRISPRs within the population to possess a significant number of spacers. Our study provides an alternative explanation for the rarity of all-resistant super microbes in nature and why proliferation of phages can be highly successful despite the effectiveness of CRISPR-Cas systems.
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Affiliation(s)
- Yekaterina S. Pavlova
- Mathematics Department, Palomar College, San Marcos, California, United States of America
| | - David Paez-Espino
- Department of Energy, Joint Genome Institute, Walnut Creek, California, United States of America
- Mammoth BioSciences, South San Francisco, California, United States of America
| | - Andrew Yu. Morozov
- School of Mathematics and Actuarial Science, University of Leicester, Leicester, United Kingdom
- Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
| | - Ilya S. Belalov
- Laboratory of Microbial Viruses, Winogradsky Institute of Microbiology, Research Center of Biotechnology RAS, Moscow, Russia
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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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Singh V. An introduction and use of the CRISPR-Cas systems. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 179:1-10. [PMID: 33785173 DOI: 10.1016/bs.pmbts.2020.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Clusters of regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated proteins (Cas) system (CRISPR-Cas) is a rapidly evolving field of targeted genome engineering. The type II CRISPR-Cas9 is used for genome editing of many organisms. Single guide RNA (sgRNA) can bind to Cas9 protein that can target desired sequences in presence of protospacer adjacent motif (PAM) sequences. This complex binds and generate a DSB that is repaired by NHEJ or HDR pathways, subsequently gene insertion/deletion (Indels) is generated that leads to change in the organism's genotype followed by its phenotype. In this chapter, CRISPR-mediated targeted genome editing in different lower organisms has been highlighted to promote its basic understanding to be applied for biotechnological, biomedical and therapeutic applications.
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Affiliation(s)
- Vijai Singh
- Department of Biosciences, School of Science, Indrashil University, Rajpur, Mehsana, Gujarat, India.
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36
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Van Orden MJ, Newsom S, Rajan R. CRISPR type II-A subgroups exhibit phylogenetically distinct mechanisms for prespacer insertion. J Biol Chem 2020; 295:10956-10968. [PMID: 32513871 DOI: 10.1074/jbc.ra120.013554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/04/2020] [Indexed: 12/20/2022] Open
Abstract
CRISPR-Cas is an adaptive immune system that protects prokaryotes against foreign nucleic acids. Prokaryotes gain immunity by acquiring short pieces of the invading nucleic acid termed prespacers and inserting them into their CRISPR array. In type II-A systems, Cas1 and Cas2 proteins insert prespacers always at the leader-repeat junction of the CRISPR array. Among type II-A CRISPR systems, three distinct groups (G1, G2, and G3) exist according to the extent of DNA sequence conservation at the 3' end of the leader. However, the mechanisms by which these conserved motifs interact with their cognate Cas1 and Cas2 proteins remain unclear. Here, we performed in vitro integration assays, finding that for G1 and G2, the insertion site is recognized through defined mechanisms, at least in members examined to date, whereas G3 exhibits no sequence-specific insertion. G1 first recognized a 12-bp sequence at the leader-repeat junction and performed leader-side insertion before proceeding to spacer-side insertion. G2 recognized the full repeat sequence and could perform independent leader-side or spacer-side insertions, although the leader-side insertion was faster than spacer-side. The prespacer morphology requirements for Cas1-Cas2 varied, with G1 stringently requiring a 5-nucleotide 3' overhang and G2 being able to insert many forms of prespacers with variable efficiencies. These results highlight the intricacy of protein-DNA sequence interactions within the seemingly similar type II-A integration complexes and provide mechanistic insights into prespacer insertion. These interactions can be fine-tuned to expand the Cas1-Cas2 toolset for inserting small DNAs into diverse DNA targets.
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Affiliation(s)
- Mason J Van Orden
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Sydney Newsom
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
| | - Rakhi Rajan
- Department of Chemistry and Biochemistry, Price Family Foundation Institute of Structural Biology, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma, USA
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Abstract
CRISPR-Cas is one of the mechanisms used by bacteria to defend against viral predation. Increasing our knowledge of the biology and diversity of CRISPR-Cas systems will also improve our understanding of virus-bacterium interactions. As CRISPR-Cas systems acquiring novel immunities under laboratory conditions are rare, Streptococcus mutans strain P42S provides an alternative model to study the adaptation step, which is still the least understood step in CRISPR-Cas biology. Furthermore, the availability of a natural Cas9 protein recognizing an AT-rich PAM opens up new avenues for genome editing purposes. Streptococcus mutans and its virulent phages are important members of the human oral microbiota. S. mutans is also the primary causal agent of dental caries. To survive in this ecological niche, S. mutans must encode phage defense mechanisms, which include CRISPR-Cas systems. Here, we describe the CRISPR-Cas type II-A system of S. mutans strain P42S, which was found to display natural adaptation and interference activity in response to phage infection and plasmid transformation. Newly acquired spacers were integrated both at the 5′ end of the CRISPR locus and ectopically. In comparisons of the cas genes of P42S to those of other strains of S. mutans, cas1, cas2, and csn2 appear to be highly conserved within the species. However, more diversity was observed with cas9. While the nuclease domains of S. mutans Cas9 (SmCas9) are conserved, the C terminus of the protein, including the protospacer adjacent motif (PAM) recognition domain, is less conserved. In support of these findings, we experimentally demonstrated that the PAMs associated with SmCas9 of strain P42S are NAA and NGAA. These PAMs are different from those previously reported for the CRISPR-Cas system of the model strain S. mutans UA159. This study illustrates the diversity of CRISPR-Cas type II-A systems that can be found within the same bacterial species. IMPORTANCE CRISPR-Cas is one of the mechanisms used by bacteria to defend against viral predation. Increasing our knowledge of the biology and diversity of CRISPR-Cas systems will also improve our understanding of virus-bacterium interactions. As CRISPR-Cas systems acquiring novel immunities under laboratory conditions are rare, Streptococcus mutans strain P42S provides an alternative model to study the adaptation step, which is still the least understood step in CRISPR-Cas biology. Furthermore, the availability of a natural Cas9 protein recognizing an AT-rich PAM opens up new avenues for genome editing purposes.
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38
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Sasnauskas G, Siksnys V. CRISPR adaptation from a structural perspective. Curr Opin Struct Biol 2020; 65:17-25. [PMID: 32570107 DOI: 10.1016/j.sbi.2020.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
Bacterial CRISPR-Cas systems provide adaptive immunity against viruses and other mobile genome elements. During the adaptation step cells become immunized by insertion of short fragments of foreign DNA, termed spacers, into the genomic region called a CRISPR array. Selection, processing and insertion of new spacers is an elaborate and precisely orchestrated reaction, which relies on the Cas1-Cas2 integrase complex and accessory proteins that vary among different types of CRISPR-Cas systems. This review focuses on CRISPR adaptation from the structural perspective, with the spotlight on adaptation proteins employed by type I and type II CRISPR-Cas systems.
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Affiliation(s)
- Giedrius Sasnauskas
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania
| | - Virginijus Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio Av. 7, Vilnius 10257, Lithuania.
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39
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Abstract
CRISPR research began over 30 years ago with the incidental discovery of an unusual nucleotide arrangement in the Escherichia coli genome. It took 20 years to find the main function of CRISPR-Cas systems as an adaptive defence mechanism against invading nucleic acids, and our knowledge of their biology has steadily increased ever since. In parallel, the number of applications derived from CRISPR-Cas systems has risen spectacularly. The CRISPR-based genome editing tool is arguably the most exciting application in both basic and applied research. Lately, CRISPR-Cas research has partially shifted to the least understood aspect of its biology: the ability of CRISPR-Cas systems to acquire new immunities during the so-called adaptation step. To date, the most efficient natural system to readily acquire new spacers is the type II-A system of the gram-positive dairy bacterium Streptococcus thermophilus. The discovery of additional systems able to acquire new spacers will hopefully draw more attention to this step of CRISPR-Cas biology. This review focuses on the breakthroughs that have helped to unravel the adaptation phase and on questions that remain to be answered.
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Affiliation(s)
- Cas Mosterd
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
| | - Geneviève M Rousseau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
| | - Sylvain Moineau
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, QC G1V 0A6, Canada.,Groupe de recherche en écologie buccale, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada.,Félix d'Hérelle Reference Center for Bacterial Viruses, Faculté de médecine dentaire, Université Laval, QC G1V 0A6, Canada
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40
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Kieper SN, Almendros C, Brouns SJJ. Conserved motifs in the CRISPR leader sequence control spacer acquisition levels in Type I-D CRISPR-Cas systems. FEMS Microbiol Lett 2020; 366:5525085. [PMID: 31252430 PMCID: PMC6607411 DOI: 10.1093/femsle/fnz129] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/27/2019] [Indexed: 12/20/2022] Open
Abstract
Integrating short DNA fragments at the correct leader-repeat junction is key to successful CRISPR-Cas memory formation. The Cas1-2 proteins are responsible to carry out this process. However, the CRISPR adaptation process additionally requires a DNA element adjacent to the CRISPR array, called leader, to facilitate efficient localization of the correct integration site. In this work, we introduced the core CRISPR adaptation genes cas1 and cas2 from the Type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and assessed spacer integration efficiency. Truncation of the leader resulted in a significant reduction of spacer acquisition levels and revealed the importance of different conserved regions for CRISPR adaptation rates. We found three conserved sequence motifs in the leader of I-D CRISPR arrays that each affected spacer acquisition rates, including an integrase anchoring site. Our findings support the model in which the leader sequence is an integral part of type I-D adaptation in Synechocystis sp. acting as a localization signal for the adaptation complex to drive CRISPR adaptation at the first repeat of the CRISPR array.
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Affiliation(s)
- Sebastian N Kieper
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Cristóbal Almendros
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Stan J J Brouns
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.,Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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41
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Brandt K, Nethery MA, O'Flaherty S, Barrangou R. Genomic characterization of Lactobacillus fermentum DSM 20052. BMC Genomics 2020; 21:328. [PMID: 32349666 PMCID: PMC7191730 DOI: 10.1186/s12864-020-6740-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/16/2020] [Indexed: 12/11/2022] Open
Abstract
Background Lactobacillus fermentum, a member of the lactic acid bacteria complex, has recently garnered increased attention due to documented antagonistic properties and interest in assessing the probiotic potential of select strains that may provide human health benefits. Here, we genomically characterize L. fermentum using the type strain DSM 20052 as a canonical representative of this species. Results We determined the polished whole genome sequence of this type strain and compared it to 37 available genome sequences within this species. Results reveal genetic diversity across nine clades, with variable content encompassing mobile genetic elements, CRISPR-Cas immune systems and genomic islands, as well as numerous genome rearrangements. Interestingly, we determined a high frequency of occurrence of diverse Type I, II, and III CRISPR-Cas systems in 72% of the genomes, with a high level of strain hypervariability. Conclusions These findings provide a basis for the genetic characterization of L. fermentum strains of scientific and commercial interest. Furthermore, our study enables genomic-informed selection of strains with specific traits for commercial product formulation, and establishes a framework for the functional characterization of features of interest.
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Affiliation(s)
- Katelyn Brandt
- Functional Genomics Graduate Program, North Carolina State University, Raleigh, NC, 27695, USA.,Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Matthew A Nethery
- Functional Genomics Graduate Program, North Carolina State University, Raleigh, NC, 27695, USA.,Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sarah O'Flaherty
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | - Rodolphe Barrangou
- Functional Genomics Graduate Program, North Carolina State University, Raleigh, NC, 27695, USA. .,Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, 27695, USA.
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42
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Pinilla-Redondo R, Mayo-Muñoz D, Russel J, Garrett RA, Randau L, Sørensen SJ, Shah SA. Type IV CRISPR-Cas systems are highly diverse and involved in competition between plasmids. Nucleic Acids Res 2020; 48:2000-2012. [PMID: 31879772 PMCID: PMC7038947 DOI: 10.1093/nar/gkz1197] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/02/2019] [Accepted: 12/13/2019] [Indexed: 12/18/2022] Open
Abstract
CRISPR-Cas systems provide prokaryotes with adaptive immune functions against viruses and other genetic parasites. In contrast to all other types of CRISPR-Cas systems, type IV has remained largely overlooked. Here, we describe a previously uncharted diversity of type IV gene cassettes, primarily encoded by plasmid-like elements from diverse prokaryotic taxa. Remarkably, via a comprehensive analysis of their CRISPR spacer content, these systems were found to exhibit a strong bias towards the targeting of other plasmids. Our data indicate that the functions of type IV systems have diverged from those of other host-related CRISPR-Cas immune systems to adopt a role in mediating conflicts between plasmids. Furthermore, we find evidence for cross-talk between certain type IV and type I CRISPR-Cas systems that co-exist intracellularly, thus providing a simple answer to the enigmatic absence of type IV adaptation modules. Collectively, our results lead to the expansion and reclassification of type IV systems and provide novel insights into the biological function and evolution of these elusive systems.
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Affiliation(s)
- Rafael Pinilla-Redondo
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
- Department of Technological Educations, University College Copenhagen, Sigurdsgade 26, 2200 Copenhagen, Denmark
| | - David Mayo-Muñoz
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Jakob Russel
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Roger A Garrett
- Danish Archaea Centre, Department of Biology, University of Copenhagen, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark
| | - Lennart Randau
- Philipps-Universität Marburg, Faculty of Biology, Hans-Meerwein-Straße 6, 35032 Marburg, Germany
| | - Søren J Sørensen
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Shiraz A Shah
- Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Ledreborg Alle 34, 2820 Gentofte, Denmark
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43
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The arms race between bacteria and their phage foes. Nature 2020; 577:327-336. [PMID: 31942051 DOI: 10.1038/s41586-019-1894-8] [Citation(s) in RCA: 415] [Impact Index Per Article: 103.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/13/2019] [Indexed: 12/26/2022]
Abstract
Bacteria are under immense evolutionary pressure from their viral invaders-bacteriophages. Bacteria have evolved numerous immune mechanisms, both innate and adaptive, to cope with this pressure. The discovery and exploitation of CRISPR-Cas systems have stimulated a resurgence in the identification and characterization of anti-phage mechanisms. Bacteriophages use an extensive battery of counter-defence strategies to co-exist in the presence of these diverse phage defence mechanisms. Understanding the dynamics of the interactions between these microorganisms has implications for phage-based therapies, microbial ecology and evolution, and the development of new biotechnological tools. Here we review the spectrum of anti-phage systems and highlight their evasion by bacteriophages.
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44
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Hickman AB, Kailasan S, Genzor P, Haase AD, Dyda F. Casposase structure and the mechanistic link between DNA transposition and spacer acquisition by CRISPR-Cas. eLife 2020; 9:50004. [PMID: 31913120 PMCID: PMC6977970 DOI: 10.7554/elife.50004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 01/08/2020] [Indexed: 12/17/2022] Open
Abstract
Key to CRISPR-Cas adaptive immunity is maintaining an ongoing record of invading nucleic acids, a process carried out by the Cas1-Cas2 complex that integrates short segments of foreign genetic material (spacers) into the CRISPR locus. It is hypothesized that Cas1 evolved from casposases, a novel class of transposases. We show here that the Methanosarcina mazei casposase can integrate varied forms of the casposon end in vitro, and recapitulates several properties of CRISPR-Cas integrases including site-specificity. The X-ray structure of the casposase bound to DNA representing the product of integration reveals a tetramer with target DNA bound snugly between two dimers in which single-stranded casposon end binding resembles that of spacer 3'-overhangs. The differences between transposase and CRISPR-Cas integrase are largely architectural, and it appears that evolutionary change involved changes in protein-protein interactions to favor Cas2 binding over tetramerization; this in turn led to preferred integration of single spacers over two transposon ends.
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Affiliation(s)
- Alison B Hickman
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Shweta Kailasan
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Pavol Genzor
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Astrid D Haase
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Fred Dyda
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
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45
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Abstract
Many bacteria and archaea have the unique ability to heritably alter their genomes by incorporating small fragments of foreign DNA, called spacers, into CRISPR loci. Once transcribed and processed into individual CRISPR RNAs, spacer sequences guide Cas effector nucleases to destroy complementary, invading nucleic acids. Collectively, these two processes are known as the CRISPR-Cas immune response. In this Progress article, we review recent studies that have advanced our understanding of the molecular mechanisms underlying spacer acquisition and that have revealed a fundamental link between the two phases of CRISPR immunity that ensures optimal immunity from newly acquired spacers. Finally, we highlight important open questions and discuss the potential basic and applied impact of spacer acquisition research.
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Affiliation(s)
- Jon McGinn
- Laboratory of Bacteriology, The Rockefeller University, New York, NY, USA
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46
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Yoganand KN, Muralidharan M, Nimkar S, Anand B. Fidelity of prespacer capture and processing is governed by the PAM-mediated interactions of Cas1-2 adaptation complex in CRISPR-Cas type I-E system. J Biol Chem 2019; 294:20039-20053. [PMID: 31748409 PMCID: PMC6937570 DOI: 10.1074/jbc.ra119.009438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 11/18/2019] [Indexed: 12/11/2022] Open
Abstract
Prokaryotes deploy CRISPR-Cas-based RNA-guided adaptive immunity to fend off mobile genetic elements such as phages and plasmids. During CRISPR adaptation, which is the first stage of CRISPR immunity, the Cas1-2 integrase complex captures invader-derived prespacer DNA and specifically integrates it at the leader-repeat junction as spacers. For this integration, several variants of CRISPR-Cas systems use Cas4 as an indispensable nuclease for selectively processing the protospacer adjacent motif (PAM) containing prespacers to a defined length. Surprisingly, however, a few CRISPR-Cas systems, such as type I-E, are bereft of Cas4. Despite the absence of Cas4, how the prespacers show impeccable conservation for length and PAM selection in type I-E remains intriguing. Here, using in vivo and in vitro integration assays, deep sequencing, and exonuclease footprinting, we show that Cas1-2/I-E-via the type I-E-specific extended C-terminal tail of Cas1-displays intrinsic affinity for PAM containing prespacers of variable length in Escherichia coli Although Cas1-2/I-E does not prune the prespacers, its binding protects the prespacer boundaries from exonuclease action. This ensures the pruning of exposed ends by exonucleases to aptly sized substrates for integration into the CRISPR locus. In summary, our work reveals that in a few CRISPR-Cas variants, such as type I-E, the specificity of PAM selection resides with Cas1-2, whereas the prespacer processing is co-opted by cellular non-Cas exonucleases, thereby offsetting the need for Cas4.
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Affiliation(s)
- Kakimani Nagarajan Yoganand
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Manasasri Muralidharan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Siddharth Nimkar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Baskaran Anand
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
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47
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Grainy J, Garrett S, Graveley BR, P Terns M. CRISPR repeat sequences and relative spacing specify DNA integration by Pyrococcus furiosus Cas1 and Cas2. Nucleic Acids Res 2019; 47:7518-7531. [PMID: 31219587 PMCID: PMC6698737 DOI: 10.1093/nar/gkz548] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 12/26/2022] Open
Abstract
Acquiring foreign spacer DNA into the CRISPR locus is an essential primary step of the CRISPR-Cas pathway in prokaryotes for developing host immunity to mobile genetic elements. Here, we investigate spacer integration in vitro using proteins from Pyrococcus furiosus and demonstrate that Cas1 and Cas2 are sufficient to accurately integrate spacers into a minimal CRISPR locus. Using high-throughput sequencing, we identified high frequency spacer integration occurring at the same CRISPR repeat border sites utilized in vivo, as well as at several non-CRISPR plasmid sequences which share features with repeats. Analysis of non-CRISPR integration sites revealed that Cas1 and Cas2 are directed to catalyze full-site spacer integration at specific DNA stretches where guanines and/or cytosines are 30 base pairs apart and the intervening sequence harbors several positionally conserved bases. Moreover, assaying a series of CRISPR repeat mutations, followed by sequencing of the integration products, revealed that the specificity of integration is primarily directed by sequences at the leader-repeat junction as well as an adenine-rich sequence block in the mid-repeat. Together, our results indicate that P. furiosus Cas1 and Cas2 recognize multiple sequence features distributed over a 30 base pair DNA region for accurate spacer integration at the CRISPR repeat.
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Affiliation(s)
- Julie Grainy
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Sandra Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Stem Cell Institute, UConn Health, Farmington, CT 06030, USA
| | - Michael P Terns
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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48
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Kim JG, Garrett S, Wei Y, Graveley BR, Terns MP. CRISPR DNA elements controlling site-specific spacer integration and proper repeat length by a Type II CRISPR-Cas system. Nucleic Acids Res 2019; 47:8632-8648. [PMID: 31392984 PMCID: PMC6895254 DOI: 10.1093/nar/gkz677] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/19/2019] [Accepted: 07/30/2019] [Indexed: 12/26/2022] Open
Abstract
CRISPR–Cas systems provide heritable immunity against viruses by capturing short invader DNA sequences, termed spacers, and incorporating them into the CRISPR loci of the prokaryotic host genome. Here, we investigate DNA elements that control accurate spacer uptake in the type II-A CRISPR locus of Streptococcus thermophilus. We determined that purified Cas1 and Cas2 proteins catalyze spacer integration with high specificity for CRISPR repeat junctions. We show that 10 bp of the CRISPR leader sequence is critical for stimulating polarized integration preferentially at the repeat proximal to the leader. Spacer integration proceeds through a two-step transesterification reaction where the 3′ hydroxyl groups of the spacer target both repeat borders on opposite strands. The leader-proximal end of the repeat is preferentially targeted for the first site of integration through recognition of sequences spanning the leader-repeat junction. Subsequently, second-site integration at the leader-distal end of the repeat is specified by multiple determinants including a length-defining mechanism relying on a repeat element proximal to the second site of integration. Our results highlight the intrinsic ability of type II Cas1/Cas2 proteins to coordinate directional and site-specific spacer integration into the CRISPR locus to ensure precise duplication of the repeat required for CRISPR immunity.
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Affiliation(s)
- Jenny G Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Sandra Garrett
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Yunzhou Wei
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Michael P Terns
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.,Department of Microbiology, University of Georgia, Athens, GA 30602, USA.,Department of Genetics, University of Georgia, Athens, GA 30602, USA
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49
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Hu T, Cui Y, Qu X. Characterization and comparison of CRISPR Loci in Streptococcus thermophilus. Arch Microbiol 2019; 202:695-710. [PMID: 31781808 DOI: 10.1007/s00203-019-01780-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/15/2019] [Accepted: 11/20/2019] [Indexed: 12/26/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) consists of a series of regular repeat-spacer sequences. It can not only act as a natural immune system in most prokaryotes, but also be utilized as the tool of newly developed genome modification and evolutionary researches. Streptococcus thermophilus is an important model organism for the study and application of CRISPR systems. In present study, the occurrence and diversity of CRISPR-Cas systems in the genomes of S. thermophilus were investigated including 4 new sequenced strains CS5, CS9, CS18, CS20, and other 23 strains downloaded from NCBI website. 66 CRISPR/Cas systems were identified among these 27 strains and could divided into four subsystems according to the arrangement of Cas proteins, notably I-E, II-A, II-C and III-A. Overall, 26 type II-C systems, 18 type II-A systems, 13 type III-A systems, 9 type I-E systems were identified. It was mentioned that CS20 contained two type II-C systems which had not been identified in the other 26 S. thermophilus strains. Overall, 1,080 spacers were analyzed and blasted. Sequence identity searches of spacers implied that most spacers derived from partial sequences of exogenous DNA, including various bacteriophages and plasmids. Of note, a large number of novel spacers were found in this study, indicating the unique phage environment they have undergone, especially CS20 strain. In addition, the analysis of the cas1 and cas9 genes revealed the genetic relationship among CRISPR-Cas system in these strains. Furthermore, the analysis of CRISPR spacers also indicated protospacer adjacent motif (PAM) sequences. Summary of PAM sequences could lay the foundations for the application of S. thermophilus CRISPR-Cas system. Our results suggested CS5 and CS18 can be used as model strains in the research of CRISPR-Cas system, and CS20 might have greater application potential in gene editing.
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Affiliation(s)
- Tong Hu
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, People's Republic of China
| | - Yanhua Cui
- Department of Food Science and Engineering, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, People's Republic of China.
| | - Xiaojun Qu
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin, 150010, People's Republic of China
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50
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Nussenzweig PM, McGinn J, Marraffini LA. Cas9 Cleavage of Viral Genomes Primes the Acquisition of New Immunological Memories. Cell Host Microbe 2019; 26:515-526.e6. [PMID: 31585845 PMCID: PMC7558852 DOI: 10.1016/j.chom.2019.09.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023]
Abstract
Type II CRISPR-Cas systems defend prokaryotes from bacteriophage infection through the acquisition of short viral DNA sequences known as spacers, which are transcribed into short RNA guides to specify the targets of the Cas9 nuclease. To counter the potentially devastating propagation of escaper phages with mutations in the target sequences, the host population acquires many different spacers. Whether and how pre-existing spacers in type II systems affect the acquisition of new ones is unknown. Here, we demonstrate that previously acquired spacers promote additional spacer acquisition from the vicinity of the target DNA site cleaved by Cas9. Therefore, CRISPR immune cells acquire additional spacers at the same time as they destroy the infecting virus. This anticipates the rise of escapers or related viruses that could escape targeting by the first spacer acquired. Our results thus reveal Cas9's role in the generation of immunological memories.
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Affiliation(s)
- Philip M Nussenzweig
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Jon McGinn
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA.
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