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Vesel N, Iseli C, Guex N, Lemopoulos A, Blokesch M. DNA modifications impact natural transformation of Acinetobacter baumannii. Nucleic Acids Res 2023; 51:5661-5677. [PMID: 37178001 PMCID: PMC10287943 DOI: 10.1093/nar/gkad377] [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: 02/09/2023] [Revised: 04/22/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Acinetobacter baumannii is a dangerous nosocomial pathogen, especially due to its ability to rapidly acquire new genetic traits, including antibiotic resistance genes (ARG). In A. baumannii, natural competence for transformation, one of the primary modes of horizontal gene transfer (HGT), is thought to contribute to ARG acquisition and has therefore been intensively studied. However, knowledge regarding the potential role of epigenetic DNA modification(s) on this process remains lacking. Here, we demonstrate that the methylome pattern of diverse A. baumannii strains differs substantially and that these epigenetic marks influence the fate of transforming DNA. Specifically, we describe a methylome-dependent phenomenon that impacts intra- and inter-species DNA exchange by the competent A. baumannii strain A118. We go on to identify and characterize an A118-specific restriction-modification (RM) system that impairs transformation when the incoming DNA lacks a specific methylation signature. Collectively, our work contributes towards a more holistic understanding of HGT in this organism and may also aid future endeavors towards tackling the spread of novel ARGs. In particular, our results suggest that DNA exchanges between bacteria that share similar epigenomes are favored and could therefore guide future research into identifying the reservoir(s) of dangerous genetic traits for this multi-drug resistant pathogen.
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Affiliation(s)
- Nina Vesel
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Christian Iseli
- Bioinformatics Competence Center, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Bioinformatics Competence Center, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Nicolas Guex
- Bioinformatics Competence Center, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Bioinformatics Competence Center, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Alexandre Lemopoulos
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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2
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Kamat A, Badrinarayanan A. SOS-independent bacterial DNA damage responses: diverse mechanisms, unifying function. Curr Opin Microbiol 2023; 73:102323. [PMID: 37148591 DOI: 10.1016/j.mib.2023.102323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/23/2023] [Accepted: 04/06/2023] [Indexed: 05/08/2023]
Abstract
Cells across domains of life have dedicated pathways to sense and respond to DNA damage. These responses are broadly termed as DNA damage responses (DDRs). In bacteria, the best studied DDR is the Save our Soul (SOS) response. More recently, several SOS-independent DDRs have also been discovered. Studies further report diversity in the types of repair proteins present across bacterial species as well as differences in their mechanisms of action. Although the primary function of DDRs is preservation of genome integrity, the diverse organization, conservation, and function of bacterial DDRs raises important questions about how genome error correction mechanisms could influence or be influenced by the genomes that encode them. In this review, we discuss recent insights on three SOS-independent bacterial DDRs. We consider open questions in our understanding of how diversity in response and repair mechanisms is generated, and how action of these pathways is regulated in cells to ensure maintenance of genome integrity.
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Affiliation(s)
- Aditya Kamat
- National Centre for Biological Sciences (TIFR), Bengaluru 560065, India
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3
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Cheng YY, Chen Z, Cao X, Ross TD, Falbel TG, Burton BM, Venturelli OS. Programming bacteria for multiplexed DNA detection. Nat Commun 2023; 14:2001. [PMID: 37037805 PMCID: PMC10086068 DOI: 10.1038/s41467-023-37582-x] [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: 02/13/2023] [Accepted: 03/23/2023] [Indexed: 04/12/2023] Open
Abstract
DNA is a universal and programmable signal of living organisms. Here we develop cell-based DNA sensors by engineering the naturally competent bacterium Bacillus subtilis (B. subtilis) to detect specific DNA sequences in the environment. The DNA sensor strains can identify diverse bacterial species including major human pathogens with high specificity. Multiplexed detection of genomic DNA from different species in complex samples can be achieved by coupling the sensing mechanism to orthogonal fluorescent reporters. We also demonstrate that the DNA sensors can detect the presence of species in the complex samples without requiring DNA extraction. The modularity of the living cell-based DNA-sensing mechanism and simple detection procedure could enable programmable DNA sensing for a wide range of applications.
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Affiliation(s)
- Yu-Yu Cheng
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Zhengyi Chen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Xinyun Cao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Tyler D Ross
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Tanya G Falbel
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Briana M Burton
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ophelia S Venturelli
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
- Department of Chemical & Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
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4
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Minhas V, Domenech A, Synefiaridou D, Straume D, Brendel M, Cebrero G, Liu X, Costa C, Baldry M, Sirard JC, Perez C, Gisch N, Hammerschmidt S, Håvarstein LS, Veening JW. Competence remodels the pneumococcal cell wall exposing key surface virulence factors that mediate increased host adherence. PLoS Biol 2023; 21:e3001990. [PMID: 36716340 PMCID: PMC9910801 DOI: 10.1371/journal.pbio.3001990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 02/09/2023] [Accepted: 01/04/2023] [Indexed: 02/01/2023] Open
Abstract
Competence development in the human pathogen Streptococcus pneumoniae controls several features such as genetic transformation, biofilm formation, and virulence. Competent bacteria produce so-called "fratricins" such as CbpD that kill noncompetent siblings by cleaving peptidoglycan (PGN). CbpD is a choline-binding protein (CBP) that binds to phosphorylcholine residues found on wall and lipoteichoic acids (WTA and LTA) that together with PGN are major constituents of the pneumococcal cell wall. Competent pneumococci are protected against fratricide by producing the immunity protein ComM. How competence and fratricide contribute to virulence is unknown. Here, using a genome-wide CRISPRi-seq screen, we show that genes involved in teichoic acid (TA) biosynthesis are essential during competence. We demonstrate that LytR is the major enzyme mediating the final step in WTA formation, and that, together with ComM, is essential for immunity against CbpD. Importantly, we show that key virulence factors PspA and PspC become more surface-exposed at midcell during competence, in a CbpD-dependent manner. Together, our work supports a model in which activation of competence is crucial for host adherence by increased surface exposure of its various CBPs.
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Affiliation(s)
- Vikrant Minhas
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland
| | - Arnau Domenech
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland
| | - Dimitra Synefiaridou
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland
| | - Daniel Straume
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Max Brendel
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, Universität Greifswald, Greifswald, Germany
| | | | - Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland,Guangdong Key Laboratory for Genome Stability and Human Disease Prevention, Department of Pharmacology, International Cancer Center, Shenzhen University Health Science Center, Shenzhen, China
| | - Charlotte Costa
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Mara Baldry
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Jean-Claude Sirard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, Universität Greifswald, Greifswald, Germany
| | - Leiv Sigve Håvarstein
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway,* E-mail: (LSH); (J-WV)
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland,* E-mail: (LSH); (J-WV)
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5
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The Helicobacter pylori UvrC Nuclease Is Essential for Chromosomal Microimports after Natural Transformation. mBio 2022; 13:e0181122. [PMID: 35876509 PMCID: PMC9426483 DOI: 10.1128/mbio.01811-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterial carcinogenic pathogen that infects the stomachs of half of the human population. It is a natural mutator due to a deficient DNA mismatch repair pathway and is naturally competent for transformation. As a result, it is one of the most genetically diverse human bacterial pathogens. The length of chromosomal imports in H. pylori follows an unusual bimodal distribution consisting of macroimports with a mean length of 1,645 bp and microimports with a mean length of 28 bp. The mechanisms responsible for this import pattern were unknown. Here, we used a high-throughput whole-genome transformation assay to elucidate the role of nucleotide excision repair pathway (NER) components on import length distribution. The data show that the integration of microimports depended on the activity of the UvrC endonuclease, while none of the other components of the NER pathway was required. Using H. pylori site-directed mutants, we showed that the widely conserved UvrC nuclease active sites, while essential for protection from UV light, one of the canonical NER functions, are not required for generation of microimports. A quantitative analysis of recombination patterns based on over 1,000 imports from over 200 sequenced recombinant genomes showed that microimports occur frequently within clusters of multiple imports, strongly suggesting they derive from a single strand invasion event. We propose a hypothetical model of homologous recombination in H. pylori, involving a novel function of UvrC, that reconciles the available experimental data about recombination patterns in H. pylori. IMPORTANCE Helicobacter pylori is one of the most common and genetically diverse human bacterial pathogens. It is responsible for chronic gastritis and represents the main risk factor for gastric cancer. In H. pylori, DNA fragments can be imported by recombination during natural transformation. The length of those fragments determines how many potentially beneficial or deleterious alleles are acquired and thus influences adaptation to the gastric niche. Here, we used a transformation assay to examine imported fragments across the chromosome. We show that UvrC, an endonuclease involved in DNA repair, is responsible for the specific integration of short DNA fragments. This suggests that short and long fragments are imported through distinct recombination pathways. We also show that short fragments are frequently clustered with longer fragments, suggesting that both pathways may be mechanistically linked. These findings provide a novel basis to explain how H. pylori can fine-tune the genetic diversity acquired by transformation.
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6
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Gibson PS, Bexkens E, Zuber S, Cowley LA, Veening JW. The acquisition of clinically relevant amoxicillin resistance in Streptococcus pneumoniae requires ordered horizontal gene transfer of four loci. PLoS Pathog 2022; 18:e1010727. [PMID: 35877768 PMCID: PMC9352194 DOI: 10.1371/journal.ppat.1010727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/04/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
Understanding how antimicrobial resistance spreads is critical for optimal application of new treatments. In the naturally competent human pathogen Streptococcus pneumoniae, resistance to β-lactam antibiotics is mediated by recombination events in genes encoding the target proteins, resulting in reduced drug binding affinity. However, for the front-line antibiotic amoxicillin, the exact mechanism of resistance still needs to be elucidated. Through successive rounds of transformation with genomic DNA from a clinically resistant isolate, we followed amoxicillin resistance development. Using whole genome sequencing, we showed that multiple recombination events occurred at different loci during one round of transformation. We found examples of non-contiguous recombination, and demonstrated that this could occur either through multiple D-loop formation from one donor DNA molecule, or by the integration of multiple DNA fragments. We also show that the final minimum inhibitory concentration (MIC) differs depending on recipient genome, explained by differences in the extent of recombination at key loci. Finally, through back transformations of mutant alleles and fluorescently labelled penicillin (bocillin-FL) binding assays, we confirm that pbp1a, pbp2b, pbp2x, and murM are the main resistance determinants for amoxicillin resistance, and that the order of allele uptake is important for successful resistance evolution. We conclude that recombination events are complex, and that this complexity contributes to the highly diverse genotypes of amoxicillin-resistant pneumococcal isolates.
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Affiliation(s)
- Paddy S. Gibson
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Evan Bexkens
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Sylvia Zuber
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Lauren A. Cowley
- Department of Biology & Biochemistry, Milner Centre for Evolution, University of Bath, Bath, United Kingdom
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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7
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Kurushima J, Tomita H. Advances of genetic engineering in Streptococci and Enterococci. Microbiol Immunol 2022; 66:411-417. [PMID: 35703039 DOI: 10.1111/1348-0421.13015] [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: 05/01/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 11/26/2022]
Abstract
In the post-genome era, reverse genetic engineering is an indispensable methodology for experimental molecular biology to provide a deeper understanding of the principal relationship between genomic features and biological phenotypes. Technically, genetic engineering is carried out through allele replacement of a target genomic locus with a designed nucleotide sequence, so called site-directed mutagenesis. To artificially manipulate allele replacement through homologous recombination, researchers have improved various methodologies that are optimized to the bacterial species of interest. Here, we review widely used genetic engineering technologies, particularly for streptococci and enterococci, and recent advances that enable more effective and flexible manipulation. The development of genetic engineering has been promoted by synthetic biology approaches based on basic biology knowledge of horizontal gene transfer systems, such as natural conjugative transfer, natural transformation, and the CRISPR/Cas system. Therefore, this review also describes basic insights into molecular biology that underlie improvements in genetic engineering technology. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jun Kurushima
- Department of Bacteriology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan
| | - Haruyoshi Tomita
- Department of Bacteriology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan.,Laboratory of Bacterial Drug Resistance, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi-shi, Gunma, 371-8511, Japan
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8
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CRISPRi-seq for genome-wide fitness quantification in bacteria. Nat Protoc 2022; 17:252-281. [PMID: 34997243 DOI: 10.1038/s41596-021-00639-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 09/24/2021] [Indexed: 02/07/2023]
Abstract
CRISPR interference (CRISPRi) is a powerful tool to link essential and nonessential genes to specific phenotypes and to explore their functions. Here we describe a protocol for CRISPRi screenings to assess genome-wide gene fitness in a single sequencing step (CRISPRi-seq). We demonstrate the use of the protocol in Streptococcus pneumoniae, an important human pathogen; however, the protocol can easily be adapted for use in other organisms. The protocol includes a pipeline for single-guide RNA library design, workflows for pooled CRISPRi library construction, growth assays and sequencing steps, a read analysis tool (2FAST2Q) and instructions for fitness quantification. We describe how to make an IPTG-inducible system with small libraries that are easy to handle and cost-effective and overcome bottleneck issues, which can be a problem when using similar, transposon mutagenesis-based methods. Ultimately, the procedure yields a fitness score per single-guide RNA target for any given growth condition. A genome-wide screening can be finished in 1 week with a constructed library. Data analysis and follow-up confirmation experiments can be completed in another 2-3 weeks.
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9
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Zhang Y, Xu S, Yang Y, Chou SH, He J. A 'time bomb' in the human intestine-the multiple emergence and spread of antibiotic-resistant bacteria. Environ Microbiol 2021; 24:1231-1246. [PMID: 34632679 DOI: 10.1111/1462-2920.15795] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/21/2021] [Accepted: 09/28/2021] [Indexed: 11/30/2022]
Abstract
Antibiotics have a strong killing effect on bacteria and are the first choice for the prevention and treatment of bacterial infectious diseases. Therefore, they have been widely used in the medical field, animal husbandry and planting industry. However, with the massive use of antibiotics, more and more antibiotic-resistant bacteria (ARB) have emerged. Because human intestines are rich in nutrients, have suitable temperature, and are high in bacterial abundance, they can easily become a hotbed for the spread of ARB and antibiotic-resistant genes (ARGs). When opportunistic pathogenic bacteria in the intestine acquire ARGs, the infectious diseases caused by such opportunistic pathogens will become more difficult to treat, or even impossible to cure. Therefore, ARB in the human intestine are like a 'time bomb'. In this review, we discuss the sources of intestinal ARB and the transmission routes of ARGs in the human intestine from the perspective of One Health. Further, we describe various methods to prevent the emergence of ARB and inhibit the spread of ARGs in the human intestine. Finally, we may be able to overcome ARB in the human intestine using an interdisciplinary 'One Health' approach.
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Affiliation(s)
- Yuling Zhang
- State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Siyang Xu
- State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yijun Yang
- State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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10
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Harnessing CRISPR-Cas9 for Genome Editing in Streptococcus pneumoniae D39V. Appl Environ Microbiol 2021; 87:AEM.02762-20. [PMID: 33397704 PMCID: PMC8105017 DOI: 10.1128/aem.02762-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/21/2020] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is an important opportunistic human pathogen killing more than 1 million people each year. Having the availability of a system capable of easy genome editing would significantly facilitate drug discovery and efforts to identify new vaccine candidates. CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against viruses and plasmids by the detection and cleavage of invading foreign DNA. Modified versions of this system can be exploited as a biotechnological tool for precise genome editing at a targeted locus. Here, we developed a replicative plasmid that carries the CRISPR-Cas9 system for RNA-programmable genome editing by counterselection in the opportunistic human pathogen Streptococcus pneumoniae. Specifically, we demonstrate an approach for making targeted markerless gene knockouts and large genome deletions. After a precise double-stranded break (DSB) is introduced, the cells’ DNA repair mechanism of homology-directed repair (HDR) is exploited to select successful transformants. This is achieved through the transformation of a template DNA fragment that will recombine in the genome and eliminate recognition of the target of the Cas9 endonuclease. Next, the newly engineered strain can be easily cured from the plasmid, which is temperature sensitive for replication, by growing it at the nonpermissive temperature. This allows for consecutive rounds of genome editing. Using this system, we engineered a strain with three major virulence factors deleted. The approaches developed here could potentially be adapted for use with other Gram-positive bacteria. IMPORTANCEStreptococcus pneumoniae (the pneumococcus) is an important opportunistic human pathogen killing more than 1 million people each year. Having the availability of a system capable of easy genome editing would significantly facilitate drug discovery and efforts to identify new vaccine candidates. Here, we introduced an easy-to-use system to perform multiple rounds of genome editing in the pneumococcus by putting the CRISPR-Cas9 system on a temperature-sensitive replicative plasmid. The approaches used here will advance genome editing projects in this important human pathogen.
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Liu X, Kimmey JM, Matarazzo L, de Bakker V, Van Maele L, Sirard JC, Nizet V, Veening JW. Exploration of Bacterial Bottlenecks and Streptococcus pneumoniae Pathogenesis by CRISPRi-Seq. Cell Host Microbe 2020; 29:107-120.e6. [PMID: 33120116 DOI: 10.1016/j.chom.2020.10.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/27/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that causes invasive diseases, including pneumonia, with greater health risks upon influenza A virus (IAV) co-infection. To facilitate pathogenesis studies in vivo, we developed an inducible CRISPR interference system that enables genome-wide fitness testing in one sequencing step (CRISPRi-seq). We applied CRISPRi-seq to assess bottlenecks and identify pneumococcal genes important in a murine pneumonia model. A critical bottleneck occurs at 48 h with few bacteria causing systemic infection. This bottleneck is not present during IAV superinfection, facilitating identification of pneumococcal pathogenesis-related genes. Top in vivo essential genes included purA, encoding adenylsuccinate synthetase, and the cps operon required for capsule production. Surprisingly, CRISPRi-seq indicated no fitness-related role for pneumolysin during superinfection. Interestingly, although metK (encoding S-adenosylmethionine synthetase) was essential in vitro, it was dispensable in vivo. This highlights advantages of CRISPRi-seq over transposon-based genetic screens, as all genes, including essential genes, can be tested for pathogenesis potential.
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Affiliation(s)
- Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Jacqueline M Kimmey
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Laura Matarazzo
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland
| | - Laurye Van Maele
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Jean-Claude Sirard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne 1015, Switzerland.
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