1
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H, Elliot MA. Multifactorial genetic control and magnesium levels govern the production of a Streptomyces antibiotic with unusual cell density dependence. mSystems 2024; 9:e0136823. [PMID: 38493407 PMCID: PMC11019849 DOI: 10.1128/msystems.01368-23] [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: 12/15/2023] [Accepted: 02/15/2024] [Indexed: 03/18/2024] Open
Abstract
Streptomyces bacteria are renowned both for their antibiotic production capabilities and for their cryptic metabolic potential. Their metabolic repertoire is subject to stringent genetic control, with many of the associated biosynthetic gene clusters being repressed by the conserved nucleoid-associated protein Lsr2. In an effort to stimulate new antibiotic production in wild Streptomyces isolates, we leveraged the activity of an Lsr2 knockdown construct and successfully enhanced antibiotic production in the wild Streptomyces isolate WAC07094. We determined that this new activity stemmed from increased levels of the angucycline-like family member saquayamycin. Saquayamycin has both antibiotic and anti-cancer activities, and intriguingly, beyond Lsr2-mediated repression, we found saquayamycin production was also suppressed at high density on solid or in liquid growth media; its levels were greatest in low-density cultures. This density-dependent control was exerted at the level of the cluster-situated regulatory gene sqnR and was mediated in part through the activity of the PhoRP two-component regulatory system, where deleting phoRP led to both constitutive antibiotic production and sqnR expression. This suggests that PhoP functions to repress the expression of sqnR at high cell density. We further discovered that magnesium supplementation could alleviate this density dependence, although its action was independent of PhoP. Finally, we revealed that the nitrogen-responsive regulators GlnR and AfsQ1 could relieve the repression exerted by Lsr2 and PhoP. Intriguingly, we found that this low density-dependent production of saquayamycin was not unique to WAC07094; saquayamycin production by another wild isolate also exhibited low-density activation, suggesting that this spatial control may serve an important ecological function in their native environments.IMPORTANCEStreptomyces specialized metabolic gene clusters are subject to complex regulation, and their products are frequently not observed under standard laboratory growth conditions. For the wild Streptomyces isolate WAC07094, production of the angucycline-family compound saquayamycin is subject to a unique constellation of control factors. Notably, it is produced primarily at low cell density, in contrast to the high cell density production typical of most antibiotics. This unusual density dependence is conserved in other saquayamycin producers and is driven by the pathway-specific regulator SqnR, whose expression is influenced by both nutritional and genetic elements. Collectively, this work provides new insights into an intricate regulatory system governing antibiotic production and indicates there may be benefits to including low-density cultures in antibiotic screening platforms.
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Affiliation(s)
- Hindra
- Institute of Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Marie A. Elliot
- Institute of Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Ontario, Canada
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2
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Norris V, Kayser C, Muskhelishvili G, Konto-Ghiorghi Y. The roles of nucleoid-associated proteins and topoisomerases in chromosome structure, strand segregation, and the generation of phenotypic heterogeneity in bacteria. FEMS Microbiol Rev 2023; 47:fuac049. [PMID: 36549664 DOI: 10.1093/femsre/fuac049] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
How to adapt to a changing environment is a fundamental, recurrent problem confronting cells. One solution is for cells to organize their constituents into a limited number of spatially extended, functionally relevant, macromolecular assemblies or hyperstructures, and then to segregate these hyperstructures asymmetrically into daughter cells. This asymmetric segregation becomes a particularly powerful way of generating a coherent phenotypic diversity when the segregation of certain hyperstructures is with only one of the parental DNA strands and when this pattern of segregation continues over successive generations. Candidate hyperstructures for such asymmetric segregation in prokaryotes include those containing the nucleoid-associated proteins (NAPs) and the topoisomerases. Another solution to the problem of creating a coherent phenotypic diversity is by creating a growth-environment-dependent gradient of supercoiling generated along the replication origin-to-terminus axis of the bacterial chromosome. This gradient is modulated by transcription, NAPs, and topoisomerases. Here, we focus primarily on two topoisomerases, TopoIV and DNA gyrase in Escherichia coli, on three of its NAPs (H-NS, HU, and IHF), and on the single-stranded binding protein, SSB. We propose that the combination of supercoiling-gradient-dependent and strand-segregation-dependent topoisomerase activities result in significant differences in the supercoiling of daughter chromosomes, and hence in the phenotypes of daughter cells.
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Affiliation(s)
- Vic Norris
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Clara Kayser
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Georgi Muskhelishvili
- Agricultural University of Georgia, School of Natural Sciences, 0159 Tbilisi, Georgia
| | - Yoan Konto-Ghiorghi
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
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3
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Getz LJ, Brown JM, Sobot L, Chow A, Mahendrarajah J, Thomas N. Attenuation of a DNA cruciform by a conserved regulator directs T3SS1 mediated virulence in Vibrio parahaemolyticus. Nucleic Acids Res 2023; 51:6156-6171. [PMID: 37158250 PMCID: PMC10325908 DOI: 10.1093/nar/gkad370] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/23/2023] [Accepted: 04/27/2023] [Indexed: 05/10/2023] Open
Abstract
Pathogenic Vibrio species account for 3-5 million annual life-threatening human infections. Virulence is driven by bacterial hemolysin and toxin gene expression often positively regulated by the winged helix-turn-helix (wHTH) HlyU transcriptional regulator family and silenced by histone-like nucleoid structural protein (H-NS). In the case of Vibrio parahaemolyticus, HlyU is required for virulence gene expression associated with type 3 Secretion System-1 (T3SS1) although its mechanism of action is not understood. Here, we provide evidence for DNA cruciform attenuation mediated by HlyU binding to support concomitant virulence gene expression. Genetic and biochemical experiments revealed that upon HlyU mediated DNA cruciform attenuation, an intergenic cryptic promoter became accessible allowing for exsA mRNA expression and initiation of an ExsA autoactivation feedback loop at a separate ExsA-dependent promoter. Using a heterologous E. coli expression system, we reconstituted the dual promoter elements which revealed that HlyU binding and DNA cruciform attenuation were strictly required to initiate the ExsA autoactivation loop. The data indicate that HlyU acts to attenuate a transcriptional repressive DNA cruciform to support T3SS1 virulence gene expression and reveals a non-canonical extricating gene regulation mechanism in pathogenic Vibrio species.
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Affiliation(s)
- Landon J Getz
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
| | - Justin M Brown
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
| | - Lauren Sobot
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
| | - Alexandra Chow
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
| | - Jastina Mahendrarajah
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
- Department of Medicine, Faculty of Medicine, Dalhousie University. Halifax, NS, Canada
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4
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Erkelens AM, Qin L, van Erp B, Miguel-Arribas A, Abia D, Keek HGJ, Markus D, Cajili MKM, Schwab S, Meijer WJJ, Dame R. The B. subtilis Rok protein is an atypical H-NS-like protein irresponsive to physico-chemical cues. Nucleic Acids Res 2022; 50:12166-12185. [PMID: 36408910 PMCID: PMC9757077 DOI: 10.1093/nar/gkac1064] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 10/20/2022] [Accepted: 10/26/2022] [Indexed: 11/22/2022] Open
Abstract
Nucleoid-associated proteins (NAPs) play a central role in chromosome organization and environment-responsive transcription regulation. The Bacillus subtilis-encoded NAP Rok binds preferentially AT-rich regions of the genome, which often contain genes of foreign origin that are silenced by Rok binding. Additionally, Rok plays a role in chromosome architecture by binding in genomic clusters and promoting chromosomal loop formation. Based on this, Rok was proposed to be a functional homolog of E. coli H-NS. However, it is largely unclear how Rok binds DNA, how it represses transcription and whether Rok mediates environment-responsive gene regulation. Here, we investigated Rok's DNA binding properties and the effects of physico-chemical conditions thereon. We demonstrate that Rok is a DNA bridging protein similar to prototypical H-NS-like proteins. However, unlike these proteins, the DNA bridging ability of Rok is not affected by changes in physico-chemical conditions. The DNA binding properties of the Rok interaction partner sRok are affected by salt concentration. This suggests that in a minority of Bacillus strains Rok activity can be modulated by sRok, and thus respond indirectly to environmental stimuli. Despite several functional similarities, the absence of a direct response to physico-chemical changes establishes Rok as disparate member of the H-NS family.
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Affiliation(s)
| | | | - Bert van Erp
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands,Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
| | - Andrés Miguel-Arribas
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - David Abia
- Bioinformatics Facility, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049 Madrid, Spain
| | - Helena G J Keek
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Dorijn Markus
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Marc K M Cajili
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands,Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
| | - Samuel Schwab
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333CC Leiden, The Netherlands,Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands,Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
| | - Wilfried J J Meijer
- Correspondence may also be addressed to Wilfried J.J. Meijer. Tel: +34 91 196 4539;
| | - Remus T Dame
- To whom correspondence should be addressed. Tel: +31 71 527 5605;
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5
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Bacterial H-NS contacts DNA at the same irregularly spaced sites in both bridged and hemi-sequestered linear filaments. iScience 2022; 25:104429. [PMID: 35669520 PMCID: PMC9162952 DOI: 10.1016/j.isci.2022.104429] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/01/2022] [Accepted: 05/13/2022] [Indexed: 11/22/2022] Open
Abstract
Gene silencing in bacteria is mediated by chromatin proteins, of which Escherichia coli H-NS is a paradigmatic example. H-NS forms nucleoprotein filaments with either one or two DNA duplexes. However, the structures, arrangements of DNA-binding domains (DBDs), and positions of DBD-DNA contacts in linear and bridged filaments are uncertain. To characterize the H-NS DBD contacts that silence transcription by RNA polymerase, we combined ·OH footprinting, molecular dynamics, statistical modeling, and DBD mapping using a chemical nuclease (Fe2+-EDTA) tethered to the DBDs (TEN-map). We find that H-NS DBDs contact DNA at indistinguishable locations in bridged or linear filaments and that the DBDs vary in orientation and position with ∼10-bp average spacing. Our results support a hemi-sequestration model of linear-to-bridged H-NS switching. Linear filaments able to inhibit only transcription initiation switch to bridged filaments able to inhibit both initiation and elongation using the same irregularly spaced DNA contacts.
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6
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Konto-Ghiorghi Y, Norris V. Hypothesis: nucleoid-associated proteins segregate with a parental DNA strand to generate coherent phenotypic diversity. Theory Biosci 2020; 140:17-25. [PMID: 33095418 DOI: 10.1007/s12064-020-00323-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/12/2020] [Indexed: 01/07/2023]
Abstract
The generation of a phenotypic diversity that is coherent across a bacterial population is a fundamental problem. We propose here that the DNA strand-specific segregation of certain nucleoid-associated proteins or NAPs results in these proteins being asymmetrically distributed to the daughter cells. We invoke a variety of mechanisms as responsible for this asymmetrical segregation including those based on differences between the leading and lagging strands, post-translational modifications, oligomerisation and association with membrane domains.
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Affiliation(s)
- Yoan Konto-Ghiorghi
- Laboratory of Microbiology Signals and Microenvironment, EA 4312, University of Rouen, 76821, Mont Saint Aignan, France
| | - Vic Norris
- Laboratory of Microbiology Signals and Microenvironment, EA 4312, University of Rouen, 76821, Mont Saint Aignan, France.
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7
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Muskhelishvili G, Forquet R, Reverchon S, Meyer S, Nasser W. Coherent Domains of Transcription Coordinate Gene Expression During Bacterial Growth and Adaptation. Microorganisms 2019; 7:microorganisms7120694. [PMID: 31847191 PMCID: PMC6956064 DOI: 10.3390/microorganisms7120694] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/28/2019] [Accepted: 12/09/2019] [Indexed: 01/07/2023] Open
Abstract
Recent studies strongly suggest that in bacteria, both the genomic pattern of DNA thermodynamic stability and the order of genes along the chromosomal origin-to-terminus axis are highly conserved and that this spatial organization plays a crucial role in coordinating genomic transcription. In this article, we explore the relationship between genomic sequence organization and transcription in the commensal bacterium Escherichia coli and the plant pathogen Dickeya. We argue that, while in E. coli the gradient of DNA thermodynamic stability and gene order along the origin-to-terminus axis represent major organizational features orchestrating temporal gene expression, the genomic sequence organization of Dickeya is more complex, demonstrating extended chromosomal domains of thermodynamically distinct DNA sequences eliciting specific transcriptional responses to various kinds of stress encountered during pathogenic growth. This feature of the Dickeya genome is likely an adaptation to the pathogenic lifestyle utilizing differences in genomic sequence organization for the selective expression of virulence traits. We propose that the coupling of DNA thermodynamic stability and genetic function provides a common organizational principle for the coordinated expression of genes during both normal and pathogenic bacterial growth.
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Affiliation(s)
| | - Raphaël Forquet
- INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, Univ. Lyon, Université Lyon 1, F-69622 Villeurbanne, France; (R.F.); (S.R.); (S.M.)
| | - Sylvie Reverchon
- INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, Univ. Lyon, Université Lyon 1, F-69622 Villeurbanne, France; (R.F.); (S.R.); (S.M.)
| | - Sam Meyer
- INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, Univ. Lyon, Université Lyon 1, F-69622 Villeurbanne, France; (R.F.); (S.R.); (S.M.)
| | - William Nasser
- INSA-Lyon, CNRS, UMR5240, Microbiologie, Adaptation, Pathogénie, Univ. Lyon, Université Lyon 1, F-69622 Villeurbanne, France; (R.F.); (S.R.); (S.M.)
- Correspondence:
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8
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Pfeifer E, Hünnefeld M, Popa O, Frunzke J. Impact of Xenogeneic Silencing on Phage-Host Interactions. J Mol Biol 2019; 431:4670-4683. [PMID: 30796986 PMCID: PMC6925973 DOI: 10.1016/j.jmb.2019.02.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/07/2019] [Accepted: 02/11/2019] [Indexed: 01/21/2023]
Abstract
Phages, viruses that prey on bacteria, are the most abundant and diverse inhabitants of the Earth. Temperate bacteriophages can integrate into the host genome and, as so-called prophages, maintain a long-term association with their host. The close relationship between host and virus has significantly shaped microbial evolution and phage elements may benefit their host by providing new functions. Nevertheless, the strong activity of phage promoters and potentially toxic gene products may impose a severe fitness burden and must be tightly controlled. In this context, xenogeneic silencing (XS) proteins, which can recognize foreign DNA elements, play an important role in the acquisition of novel genetic information and facilitate the evolution of regulatory networks. Currently known XS proteins fall into four classes (H-NS, MvaT, Rok and Lsr2) and have been shown to follow a similar mode of action by binding to AT-rich DNA and forming an oligomeric nucleoprotein complex that silences gene expression. In this review, we focus on the role of XS proteins in phage-host interactions by highlighting the important function of XS proteins in maintaining the lysogenic state and by providing examples of how phages fight back by encoding inhibitory proteins that disrupt XS functions in the host. Sequence analysis of available phage genomes revealed the presence of genes encoding Lsr2-type proteins in the genomes of phages infecting Actinobacteria. These data provide an interesting perspective for future studies to elucidate the impact of phage-encoded XS homologs on the phage life cycle and phage-host interactions.
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Affiliation(s)
- Eugen Pfeifer
- Forschungszentrum Jülich GmbH, Institute for Bio- and Geosciences 1, IBG1, 52425 Jülich, Germany.
| | - Max Hünnefeld
- Forschungszentrum Jülich GmbH, Institute for Bio- and Geosciences 1, IBG1, 52425 Jülich, Germany
| | - Ovidiu Popa
- Heinrich Heine Universität Düsseldorf, Institute for Quantitative and Theoretical Biology, 40223 Düsseldorf, Germany
| | - Julia Frunzke
- Forschungszentrum Jülich GmbH, Institute for Bio- and Geosciences 1, IBG1, 52425 Jülich, Germany.
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9
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Gehrke EJ, Zhang X, Pimentel-Elardo SM, Johnson AR, Rees CA, Jones SE, Hindra, Gehrke SS, Turvey S, Boursalie S, Hill JE, Carlson EE, Nodwell JR, Elliot MA. Silencing cryptic specialized metabolism in Streptomyces by the nucleoid-associated protein Lsr2. eLife 2019; 8:47691. [PMID: 31215866 PMCID: PMC6584129 DOI: 10.7554/elife.47691] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022] Open
Abstract
Lsr2 is a nucleoid-associated protein conserved throughout the actinobacteria, including the antibiotic-producing Streptomyces. Streptomyces species encode paralogous Lsr2 proteins (Lsr2 and Lsr2-like, or LsrL), and we show here that of the two, Lsr2 has greater functional significance. We found that Lsr2 binds AT-rich sequences throughout the chromosome, and broadly represses gene expression. Strikingly, specialized metabolic clusters were over-represented amongst its targets, and the cryptic nature of many of these clusters appears to stem from Lsr2-mediated repression. Manipulating Lsr2 activity in model species and uncharacterized isolates resulted in the production of new metabolites not seen in wild type strains. Our results suggest that the transcriptional silencing of biosynthetic clusters by Lsr2 may protect Streptomyces from the inappropriate expression of specialized metabolites, and provide global control over Streptomyces’ arsenal of signaling and antagonistic compounds.
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Affiliation(s)
- Emma J Gehrke
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Xiafei Zhang
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | | | - Andrew R Johnson
- Department of Chemistry, Indiana University, Bloomington, United States
| | - Christiaan A Rees
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Stephanie E Jones
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Hindra
- Department of Biology, McMaster University, Hamilton, Canada
| | - Sebastian S Gehrke
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Sonya Turvey
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Suzanne Boursalie
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
| | - Jane E Hill
- Geisel School of Medicine and Thayer School of Engineering, Dartmouth College, Hanover, United States
| | - Erin E Carlson
- Department of Chemistry, Indiana University, Bloomington, United States.,Department of Chemistry, University of Minnesota, Minneapolis, United States
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Marie A Elliot
- Department of Biology, McMaster University, Hamilton, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Canada
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10
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Flores-Ríos R, Quatrini R, Loyola A. Endogenous and Foreign Nucleoid-Associated Proteins of Bacteria: Occurrence, Interactions and Effects on Mobile Genetic Elements and Host's Biology. Comput Struct Biotechnol J 2019; 17:746-756. [PMID: 31303979 PMCID: PMC6606824 DOI: 10.1016/j.csbj.2019.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 02/08/2023] Open
Abstract
Mobile Genetic Elements (MGEs) are mosaics of functional gene modules of diverse evolutionary origin and are generally divergent from the hosts´ genetic background. Existing biases in base composition and codon usage of these elements` genes impose transcription and translation limitations that may affect the physical and regulatory integration of MGEs in new hosts. Stable appropriation of the foreign DNA depends on a number of host factors among which are the Nucleoid-Associated Proteins (NAPs). These small, basic, highly abundant proteins bind and bend DNA, altering its topology and folding, thereby affecting all known essential DNA metabolism related processes. Both chromosomally- (endogenous) and MGE- (foreign) encoded NAPs have been shown to exist in bacteria. While the role of host-encoded NAPs in xenogeneic silencing of both episomal (plasmids) and integrative MGEs (pathogenicity islands and prophages) is well acknowledged, less is known about the role of MGE-encoded NAPs in the foreign elements biology or their influence on the host's chromosome expression dynamics. Here we review existing literature on the topic, present examples on the positive and negative effects that endogenous and foreign NAPs exert on global transcriptional gene expression, MGE integrative and excisive recombination dynamics, persistence and transfer to suitable hosts and discuss the nature and relevance of synergistic and antagonizing higher order interactions between diverse types of NAPs.
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Affiliation(s)
| | - Raquel Quatrini
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile.,Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile
| | - Alejandra Loyola
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile
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11
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Shahul Hameed UF, Liao C, Radhakrishnan AK, Huser F, Aljedani SS, Zhao X, Momin AA, Melo FA, Guo X, Brooks C, Li Y, Cui X, Gao X, Ladbury JE, Jaremko Ł, Jaremko M, Li J, Arold ST. H-NS uses an autoinhibitory conformational switch for environment-controlled gene silencing. Nucleic Acids Res 2019; 47:2666-2680. [PMID: 30597093 PMCID: PMC6411929 DOI: 10.1093/nar/gky1299] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 12/11/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022] Open
Abstract
As an environment-dependent pleiotropic gene regulator in Gram-negative bacteria, the H-NS protein is crucial for adaptation and toxicity control of human pathogens such as Salmonella, Vibrio cholerae or enterohaemorrhagic Escherichia coli. Changes in temperature affect the capacity of H-NS to form multimers that condense DNA and restrict gene expression. However, the molecular mechanism through which H-NS senses temperature and other physiochemical parameters remains unclear and controversial. Combining structural, biophysical and computational analyses, we show that human body temperature promotes unfolding of the central dimerization domain, breaking up H-NS multimers. This unfolding event enables an autoinhibitory compact H-NS conformation that blocks DNA binding. Our integrative approach provides the molecular basis for H-NS-mediated environment-sensing and may open new avenues for the control of pathogenic multi-drug resistant bacteria.
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Affiliation(s)
- Umar F Shahul Hameed
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
| | - Chenyi Liao
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA
| | - Anand K Radhakrishnan
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
| | - Franceline Huser
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
| | - Safia S Aljedani
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
| | - Xiaochuan Zhao
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA
| | - Afaque A Momin
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
| | - Fernando A Melo
- Department of Physics (IBILCE), São Paulo State University, São José do Rio Preto, São Paulo, Brazil
| | - Xianrong Guo
- King Abdullah University of Science and Technology (KAUST), Imaging and Characterization Core Lab, Thuwal, 23955-6900, Saudi Arabia
| | - Claire Brooks
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA
| | - Yu Li
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - Xuefeng Cui
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - Xin Gao
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Computer, Electrical and Mathematical Sciences and Engineering Division (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - John E Ladbury
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Łukasz Jaremko
- King Abdullah University of Science and Technology (KAUST), Division of Biological and Environmental Sciences and Engineering, Thuwal, 23955-6900, Saudi Arabia
| | - Mariusz Jaremko
- King Abdullah University of Science and Technology (KAUST), Division of Biological and Environmental Sciences and Engineering, Thuwal, 23955-6900, Saudi Arabia
| | - Jianing Li
- Department of Chemistry, The University of Vermont, Burlington, VT 05405, USA
| | - Stefan T Arold
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, 23955-6900,Saudi Arabia
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