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Geyman LJ, Tanner MP, Rosario-Meléndez N, Peters JM, Mandel MJ, van Kessel JC. Mobile-CRISPRi as a powerful tool for modulating Vibrio gene expression. Appl Environ Microbiol 2024:e0006524. [PMID: 38775491 DOI: 10.1128/aem.00065-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/28/2024] [Indexed: 05/25/2024] Open
Abstract
CRISPRi (Clustered Regularly Interspaced Palindromic Repeats interference) is a gene knockdown method that uses a deactivated Cas9 protein (dCas9) that binds a specific gene target locus dictated by an encoded guide RNA (sgRNA) to block transcription. Mobile-CRISPRi is a suite of modular vectors that enable CRISPRi knockdowns in diverse bacteria by integrating IPTG-inducible dcas9 and sgRNA genes into the genome using Tn7 transposition. Here, we show that the Mobile-CRISPRi system functions robustly and specifically in multiple Vibrio species: Vibrio cholerae, Vibrio fischeri, Vibrio vulnificus, Vibrio parahaemolyticus, and Vibrio campbellii. We demonstrate efficacy by targeting both essential and non-essential genes that function to produce defined, measurable phenotypes: bioluminescence, quorum sensing, cell division, and growth arrest. We anticipate that Mobile-CRISPRi will be used in Vibrio species to systematically probe gene function and essentiality in various behaviors and native environments.IMPORTANCEThe genetic manipulation of bacterial genomes is an invaluable tool in experimental microbiology. The development of CRISPRi (Clustered Regularly Interspaced Palindromic Repeats interference) tools has revolutionized genetics in many organisms, including bacteria. Here, we optimized the use of Mobile-CRISPRi in five Vibrio species, each of which has significant impacts on marine environments and organisms that include squid, shrimp, shellfish, finfish, corals, and multiple of which pose direct threats to human health. The Mobile-CRISPRi technology is easily adaptable, moveable from strain to strain, and enables researchers to selectively turn off gene expression. Our experiments demonstrate Mobile-CRISPRi is effective and robust at repressing gene expression of both essential and non-essential genes in Vibrio species.
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Affiliation(s)
- Logan J Geyman
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Madeline P Tanner
- Department of Microbiology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Natalia Rosario-Meléndez
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M Peters
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mark J Mandel
- Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Zhang Q, Alter T, Fleischmann S. Non-O1/Non-O139 Vibrio cholerae-An Underestimated Foodborne Pathogen? An Overview of Its Virulence Genes and Regulatory Systems Involved in Pathogenesis. Microorganisms 2024; 12:818. [PMID: 38674762 PMCID: PMC11052320 DOI: 10.3390/microorganisms12040818] [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: 02/29/2024] [Revised: 04/05/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
In recent years, the number of foodborne infections with non-O1 and non-O139 Vibrio cholerae (NOVC) has increased worldwide. These have ranged from sporadic infection cases to localized outbreaks. The majority of case reports describe self-limiting gastroenteritis. However, severe gastroenteritis and even cholera-like symptoms have also been described. All reported diarrheal cases can be traced back to the consumption of contaminated seafood. As climate change alters the habitats and distribution patterns of aquatic bacteria, there is a possibility that the number of infections and outbreaks caused by Vibrio spp. will further increase, especially in countries where raw or undercooked seafood is consumed or clean drinking water is lacking. Against this background, this review article focuses on a possible infection pathway and how NOVC can survive in the human host after oral ingestion, colonize intestinal epithelial cells, express virulence factors causing diarrhea, and is excreted by the human host to return to the environment.
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Affiliation(s)
| | | | - Susanne Fleischmann
- Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, Königsweg 69, 14163 Berlin, Germany; (Q.Z.); (T.A.)
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Rasal TA, Mallery CP, Brockley MW, Brown LC, Paczkowski JE, van Kessel JC. Ligand binding determines proteolytic stability of Vibrio LuxR/HapR quorum sensing transcription factors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.15.580527. [PMID: 38405947 PMCID: PMC10888775 DOI: 10.1101/2024.02.15.580527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
In Vibrio species, quorum sensing signaling culminates in the production of a TetR-type master transcription factor collectively called the LuxR/HapR family, which regulates genes required for colonization and infection of host organisms. These proteins possess a solvent accessible putative ligand binding pocket. However, a native ligand has not been identified, and the role of ligand binding in LuxR/HapR function in Vibrionaceae is unknown. To probe the role of the ligand binding pocket, we utilize the small molecule thiophenesulfonamide inhibitor PTSP (3- p henyl-1-( t hiophen-2-yl s ulfonyl)-1 H - p yrazole) that we previously showed targets LuxR/HapR proteins. Amino acid conservation in the ligand binding pocket determines the specificity and efficacy of PTSP inhibition across Vibrio species. Here, we used structure-function analyses to identify PTSP-interacting residues in the ligand binding pocket of SmcR - the Vibrio vulnificus LuxR/HapR homolog - that are required for PTSP inhibition of SmcR activity in vivo . Forward genetic screening combined with X-ray crystallography structural determination of SmcR bound to PTSP identified substitutions at eight residues that were sufficient to reduce or eliminate PTSP-mediated SmcR inhibition. Small-angle X-ray scattering and computational modeling determined that PTSP drives allosteric unfolding at the N-terminal DNA binding domain. We discovered that SmcR is degraded by the ClpAP protease in the presence of PTSP in vivo ; substitution of key PTSP-interacting residues stabilized or increased SmcR levels in the cell. This mechanism of inhibition is observed for all thiophenesulfonamide compounds tested and against other Vibrio species. We conclude that thiophenesulfonamides specifically bind in the ligand binding pocket of LuxR/HapR proteins, promoting protein degradation and thereby suppressing downstream gene expression, implicating ligand binding as a mediator of LuxR/HapR protein stability and function to govern virulence gene expression in Vibrio pathogens. SIGNIFICANCE LuxR/HapR proteins were discovered in the 1990s as central regulators of quorum sensing gene expression and later discovered to be conserved in all studied Vibrio species. LuxR/HapR homologs regulate a wide range of genes involved in pathogenesis, including but not limited to genes involved in biofilm production and toxin secretion. As archetypal members of the broad class of TetR-type transcription factors, each LuxR/HapR protein has a predicted ligand binding pocket. However, no ligand has been identified for LuxR/HapR proteins that control their function as regulators. Here, we used LuxR/HapR-specific chemical inhibitors to determine that ligand binding drives proteolytic degradation in vivo , the first demonstration of LuxR/HapR function connected to ligand binding for this historical protein family.
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Simpson CA, Celentano Z, McKinlay JB, Nadell CD, van Kessel JC. Bacterial quorum sensing controls carbon metabolism to optimize growth in changing environmental conditions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.21.576522. [PMID: 38328067 PMCID: PMC10849521 DOI: 10.1101/2024.01.21.576522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Bacteria sense population density via the cell-cell communication system called quorum sensing (QS). Some QS-regulated phenotypes ( e.g. , secreted enzymes, chelators), are public goods exploitable by cells that stop producing them. We uncovered a phenomenon in which Vibrio cells optimize expression of the methionine and tetrahydrofolate (THF) synthesis genes via QS. Strains that are genetically 'locked' at high cell density grow slowly in minimal glucose media and suppressor mutants accumulate via inactivating-mutations in metF (methylenetetrahydrofolate reductase) and luxR (the master QS transcriptional regulator). Methionine/THF synthesis genes are repressed at low cell density when glucose is plentiful and are de-repressed by LuxR at high cell density as glucose becomes limiting. In mixed cultures, QS mutant strains initially co-exist with wild-type, but as glucose is depleted, wild-type outcompetes the QS mutants. Thus, QS regulation of methionine/THF synthesis is a fitness benefit that links private and public goods within the QS regulon, preventing accumulation of QS-defective mutants.
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Geyman L, Tanner M, Rosario-Melendez N, Peters J, Mandel MJ, van Kessel JC. Mobile-CRISPRi as a powerful tool for modulating Vibrio gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.575898. [PMID: 38293084 PMCID: PMC10827217 DOI: 10.1101/2024.01.17.575898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
CRISPRi (Clustered Regularly Interspaced Palindromic Repeats interference) is a gene knockdown method that uses a deactivated Cas9 protein (dCas9) that binds a specific gene target locus dictated by an encoded guide RNA (sgRNA) to block transcription. Mobile-CRISPRi is a suite of modular vectors that enable CRISPRi knockdowns in diverse bacteria by integrating IPTG-inducible dcas9 and sgRNA genes into the genome using Tn 7 transposition. Here, we show that the Mobile-CRISPRi system functions robustly and specifically in multiple Vibrio species: Vibrio cholerae, Vibrio fischeri, Vibrio vulnificus, Vibrio parahaemolyticus , and Vibrio campbellii . We demonstrate efficacy by targeting both essential and non-essential genes that function to produce defined, measurable phenotypes: bioluminescence, quorum sensing, cell division, and growth arrest. We anticipate that Mobile-CRISPRi will be used in Vibrio species to systematically probe gene function and essentiality in various behaviors and native environments.
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Oliveira RA, Cabral V, Torcato I, Xavier KB. Deciphering the quorum-sensing lexicon of the gut microbiota. Cell Host Microbe 2023; 31:500-512. [PMID: 37054672 DOI: 10.1016/j.chom.2023.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The enduring coexistence between the gut microbiota and the host has led to a symbiotic relationship that benefits both parties. In this complex, multispecies environment, bacteria can communicate through chemical molecules to sense and respond to the chemical, physical, and ecological properties of the surrounding environment. One of the best-studied cell-to-cell communication mechanisms is quorum sensing. Chemical signaling through quorum sensing is involved in regulating the bacterial group behaviors, often required for host colonization. However, most microbial-host interactions regulated by quorum sensing are studied in pathogens. Here, we will focus on the latest reports on the emerging studies of quorum sensing in the gut microbiota symbionts and on group behaviors adopted by these bacteria to colonize the mammalian gut. Moreover, we address the challenges and approaches to uncover molecule-mediated communication mechanisms, which will allow us to unravel the processes that drive the establishment of gut microbiota.
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Affiliation(s)
| | - Vitor Cabral
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Inês Torcato
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
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Miller Conrad LC, Perez LJ. A Geneticist Transcribing the Chemical Language of Bacteria. Isr J Chem 2022. [DOI: 10.1002/ijch.202200079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
| | - Lark J. Perez
- Department of Chemistry & Biochemistry Rowan University 201 Mullica Hill Rd Glassboro NJ 08028 USA
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Simpson CA, Petersen BD, Haas NW, Geyman LJ, Lee AH, Podicheti R, Pepin R, Brown LC, Rusch DB, Manzella MP, Papenfort K, van Kessel JC. The quorum-sensing systems of Vibrio campbellii DS40M4 and BB120 are genetically and functionally distinct. Environ Microbiol 2021; 23:5412-5432. [PMID: 33998118 PMCID: PMC8458232 DOI: 10.1111/1462-2920.15602] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 05/13/2021] [Indexed: 11/28/2022]
Abstract
Vibrio campbellii BB120 (previously classified as Vibrio harveyi) is a fundamental model strain for studying quorum sensing in vibrios. A phylogenetic evaluation of sequenced Vibrio strains in Genbank revealed that BB120 is closely related to the environmental isolate V. campbellii DS40M4. We exploited DS40M4's competence for exogenous DNA uptake to rapidly generate greater than 30 isogenic strains with deletions of genes encoding BB120 quorum-sensing system homologues. Our results show that the quorum-sensing circuit of DS40M4 is distinct from BB120 in three ways: (i) DS40M4 does not produce an acyl homoserine lactone autoinducer but encodes an active orphan LuxN receptor, (ii) the quorum regulatory small RNAs (Qrrs) are not solely regulated by autoinducer signalling through the response regulator LuxO and (iii) the DS40M4 quorum-sensing regulon is much smaller than BB120 (~100 genes vs. ~400 genes, respectively). Using comparative genomics to expand our understanding of quorum-sensing circuit diversity, we observe that conservation of LuxM/LuxN proteins differs widely both between and within Vibrio species. These strains are also phenotypically distinct: DS40M4 exhibits stronger interbacterial cell killing, whereas BB120 forms more robust biofilms and is bioluminescent. These results underscore the need to examine wild isolates for a broader view of bacterial diversity in the marine ecosystem.
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Affiliation(s)
| | | | - Nicholas W Haas
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Logan J Geyman
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Aimee H Lee
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Ram Podicheti
- Centre for Genomics and Bioinformatics, Indiana University, Bloomington, IN, USA
| | - Robert Pepin
- Mass Spectrometry Facility, Indiana University, Bloomington, IN, USA
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Laura C Brown
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - Douglas B Rusch
- Centre for Genomics and Bioinformatics, Indiana University, Bloomington, IN, USA
| | | | - Kai Papenfort
- Friedrich Schiller University, Institute of Microbiology, Jena, Germany
- Microverse Cluster, Friedrich Schiller University Jena, Jena, Germany
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Wale KR, Cottam C, Connolly JP, Roe AJ. Transcriptional and metabolic regulation of EHEC and Citrobacter rodentium pathogenesis. Curr Opin Microbiol 2021; 63:70-75. [PMID: 34224961 DOI: 10.1016/j.mib.2021.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/04/2021] [Accepted: 06/16/2021] [Indexed: 11/24/2022]
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) is a gastrointestinal pathogen that colonizes the colonic epithelium of humans and ruminants using a Type Three Secretion System (T3SS). This system is indispensable for disease and is regulated in response to a plethora of host and microbiota derived signals. The murine pathogen, Citrobacter rodentium, has become an instrumental tool in studying EHEC infection mechanisms in vivo, given its natural ability to infect mice and reliance on the same colonisation machinery. Here, we provide a review of the most recent advancements in EHEC infection biology, focusing on transcriptional regulation of the T3SS in response to physiologically relevant signals and how colonisation impacts on the metabolic micro-environment of the host niche. We pay particular attention to studies that have employed the C. rodentium model for elucidation of such mechanisms in vivo.
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Affiliation(s)
- Kabo R Wale
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Curtis Cottam
- Newcastle University Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
| | - James Pr Connolly
- Newcastle University Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK
| | - Andrew J Roe
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
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