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Åberg A, Gideonsson P, Bhat A, Ghosh P, Arnqvist A. Molecular insights into the fine-tuning of pH-dependent ArsR-mediated regulation of the SabA adhesin in Helicobacter pylori. Nucleic Acids Res 2024; 52:5572-5595. [PMID: 38499492 PMCID: PMC11162790 DOI: 10.1093/nar/gkae188] [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: 12/20/2023] [Revised: 02/28/2024] [Accepted: 03/12/2024] [Indexed: 03/20/2024] Open
Abstract
Adaptation to variations in pH is crucial for the ability of Helicobacter pylori to persist in the human stomach. The acid responsive two-component system ArsRS, constitutes the global regulon that responds to acidic conditions, but molecular details of how transcription is affected by the ArsR response regulator remains poorly understood. Using a combination of DNA-binding studies, in vitro transcription assays, and H. pylori mutants, we demonstrate that phosphorylated ArsR (ArsR-P) forms an active protein complex that binds DNA with high specificity in order to affect transcription. Our data showed that DNA topology is key for DNA binding. We found that AT-rich DNA sequences direct ArsR-P to specific sites and that DNA-bending proteins are important for the effect of ArsR-P on transcription regulation. The repression of sabA transcription is mediated by ArsR-P with the support of Hup and is affected by simple sequence repeats located upstream of the sabA promoter. Here stochastic events clearly contribute to the fine-tuning of pH-dependent gene regulation. Our results reveal important molecular aspects for how ArsR-P acts to repress transcription in response to acidic conditions. Such transcriptional control likely mediates shifts in bacterial positioning in the gastric mucus layer.
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Affiliation(s)
- Anna Åberg
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Pär Gideonsson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Abhayprasad Bhat
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Prachetash Ghosh
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Anna Arnqvist
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
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2
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Al-Wahaibi ASM, Upstill-Goddard RC, Burgess JG. Isolation and Staining Reveal the Presence of Extracellular DNA in Marine Gel Particles. Gels 2023; 9:gels9030251. [PMID: 36975700 PMCID: PMC10048003 DOI: 10.3390/gels9030251] [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: 02/22/2023] [Revised: 03/07/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Marine gel particles (MGP) are amorphous hydrogel exudates from bacteria and microalgae that are ubiquitous in the oceans, but their biochemical composition and function are poorly understood. While dynamic ecological interactions between marine microorganisms and MGPs may result in the secretion and mixing of bacterial extracellular polymeric substances (EPS) such as nucleic acids, compositional studies currently are limited to the identification of acidic polysaccharides and proteins in transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP). Previous studies targeted MGPs isolated by filtration. We developed a new way of isolating MGPs from seawater in liquid suspension and applied it to identify extracellular DNA (eDNA) in North Sea surface seawater. Seawater was filtered onto polycarbonate (PC) filters with gentle vacuum filtration, and then the filtered particles were gently resuspended in a smaller volume of sterile seawater. The resulting MGPs ranged in size from 0.4 to 100 µm in diameter. eDNA was detected by fluorescent microscopy using YOYO-1 (for eDNA), with Nile red (targeting cell membranes) as a counterstain. TOTO-3 was also used to stain eDNA, with ConA to localise glycoproteins and SYTO-9 for the live/dead staining of cells. Confocal laser scanning microscopy (CLSM) revealed the presence of proteins and polysaccharides. We found eDNA to be universally associated with MGPs. To further elucidate the role of eDNA, we established a model experimental MGP system using bacterial EPS from Pseudoalteromonas atlantica that also contained eDNA. Our results clearly demonstrate the occurrence of eDNA in MGPs, and should aid furthering our understanding of the micro-scale dynamics and fate of MGPs that underly the large-scale processes of carbon cycling and sedimentation in the ocean.
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Affiliation(s)
- Aisha S M Al-Wahaibi
- Centre of Excellence in Marine Biotechnology, Sultan Qaboos University, P.O. Box 50, Muscat 123, Oman
| | - Robert C Upstill-Goddard
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - J Grant Burgess
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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3
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The Colorectal Cancer Microbiota Alter Their Transcriptome To Adapt to the Acidity, Reactive Oxygen Species, and Metabolite Availability of Gut Microenvironments. mSphere 2023; 8:e0062722. [PMID: 36847536 PMCID: PMC10117117 DOI: 10.1128/msphere.00627-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
The gut microbiome is implicated in the pathology of colorectal cancer (CRC). However, the mechanisms by which the microbiota actively contribute to disease onset and progression remain elusive. In this pilot study, we sequenced fecal metatranscriptomes of 10 non-CRC and 10 CRC patient gut microbiomes and conducted differential gene expression analyses to assess any changed functionality in disease. We report that oxidative stress responses were the dominant activity across cohorts, an overlooked protective housekeeping role of the human gut microbiome. However, expression of hydrogen peroxide and nitric oxide-scavenging genes was diminished and augmented, respectively, positing that these regulated microbial responses have implications for CRC pathology. CRC microbes enhanced expression of genes for host colonization, biofilm formation, genetic exchange, virulence determinants, antibiotic, and acid resistances. Moreover, microbes promoted transcription of genes involved in metabolism of several beneficial metabolites, suggesting their contribution to patient metabolite deficiencies previously solely attributed to tumor cells. We showed in vitro that expression of genes involved in amino acid-dependent acid resistance mechanisms of meta-gut Escherichia coli responded differently to acid, salt, and oxidative pressures under aerobic conditions. These responses were mostly dictated by the host health status of origin of the microbiota, suggesting their exposure to fundamentally different gut conditions. These findings for the first time highlight mechanisms by which the gut microbiota can either protect against or drive colorectal cancer and provide insights into the cancerous gut environment that drives functional characteristics of the microbiome. IMPORTANCE The human gut microbiota has the genetic potential to drive colorectal cancer onset and progression; however, the expression of this genetic potential during the disease has not been investigated. We found that microbial expression of genes that detoxify DNA-damaging reactive oxygen species, which drive colorectal cancer, is compromised in cancer. We observed a greater activation of expression of genes involved in virulence, host colonization, exchange of genetic material, metabolite utilization, defense against antibiotics, and environmental pressures. Culturing gut Escherichia coli of cancerous and noncancerous metamicrobiota revealed different regulatory responses of amino acid-dependent acid resistance mechanisms in a health-dependent manner under environmental acid, oxidative, and osmotic pressures. Here, for the first time, we demonstrate that the activity of microbial genomes is regulated by the health status of the gut in vivo and in vitro and provides new insights for shifts in microbial gene expression in colorectal cancer.
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4
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Choudhary E, Sharma R, Pal P, Agarwal N. Deciphering the Proteomic Landscape of Mycobacterium tuberculosis in Response to Acid and Oxidative Stresses. ACS OMEGA 2022; 7:26749-26766. [PMID: 35936415 PMCID: PMC9352160 DOI: 10.1021/acsomega.2c03092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
The fundamental to the pathogenicity of Mycobacterium tuberculosis (Mtb) is the modulation in the control mechanisms that play a role in sensing and counteracting the microbicidal milieu encompassing various cellular stresses inside the human host. To understand such changes, we measured the cellular proteome of Mtb subjected to different stresses using a quantitative proteomics approach. We identified defined sets of Mtb proteins that are modulated in response to acid and a sublethal dose of diamide and H2O2 treatments. Notably, proteins involved in metabolic, catalytic, and binding functions are primarily affected under these stresses. Moreover, our analysis led to the observations that during acidic stress Mtb enters into energy-saving mode simultaneously modulating the acid tolerance system, whereas under diamide and H2O2 stresses, there were prominent changes in the biosynthesis and homeostasis pathways, primarily modifying the resistance mechanism in diamide-treated bacteria while causing metabolic arrest in H2O2-treated bacilli. Overall, we delineated the adaptive mechanisms that Mtb may utilize under physiological stresses and possible overlap between the responses to these stress conditions. In addition to offering important protein signatures that can be exploited for future mechanistic studies, our study highlights the importance of proteomics in understanding complex adjustments made by the human pathogen during infection.
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Affiliation(s)
- Eira Choudhary
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Symbiosis
School of Biomedical Sciences, Symbiosis
International (Deemed University), Pune412115, Maharashtra, India
| | - Rishabh Sharma
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
| | - Pramila Pal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Jawaharlal
Nehru University, New
Mehrauli Road, New Delhi110067, India
| | - Nisheeth Agarwal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
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5
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Agarwal N, Nagar N, Raj R, Kumar D, Poluri KM. Conserved Apical Proline Regulating the Structure and DNA Binding Properties of Helicobacter pylori Histone-like DNA Binding Protein (Hup). ACS OMEGA 2022; 7:15231-15246. [PMID: 35572751 PMCID: PMC9089689 DOI: 10.1021/acsomega.2c01754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Prokaryotic cells lack a proper dedicated nuclear arrangement machinery. A set of proteins known as nucleoid associated proteins (NAPs) perform opening and closure of nucleic acids, behest cellular requirement. Among these, a special class of proteins analogous to eukaryotic histones popularly known as histone-like (HU) DNA binding proteins facilitate the nucleic acid folding/compaction thereby regulating gene architecture and gene regulation. DNA compaction and DNA protection in Helicobacter pylori is performed by HU protein (Hup). To dissect and galvanize the role of proline residue in the binding of Hup with DNA, the structure-dynamics-functional relationship of Hup-P64A variant was analyzed. NMR and biophysical studies evidenced that Hup-P64A protein attenuated DNA-binding and induced structural/stability changes in the DNA binding domain (DBD). Moreover, molecular dynamics simulations and 15N relaxation studies established the reduced conformational dynamics of P64A protein. This comprehensive study dissected the exclusive role of evolutionarily conserved apical proline residue in regulating the structure and DNA binding of Hup protein as P64 is presumed to be involved in the external leverage mechanism responsible for DNA bending and packaging, as proline rings wedge into the DNA backbone through intercalation besides their significant role in DNA binding.
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Affiliation(s)
- Nipanshu Agarwal
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Nupur Nagar
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Ritu Raj
- Centre
of Biomedical Research, SGPGIMS Campus, Lucknow-226014, India
| | - Dinesh Kumar
- Centre
of Biomedical Research, SGPGIMS Campus, Lucknow-226014, India
| | - Krishna Mohan Poluri
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
- Centre
for Nanotechnology, Indian Institute of
Technology Roorkee, Roorkee-247667, Uttarakhand, India
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6
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Pal P, Modi M, Ravichandran S, Yennamalli RM, Priyadarshini R. DNA-Binding Properties of YbaB, a Putative Nucleoid-Associated Protein From Caulobacter crescentus. Front Microbiol 2021; 12:733344. [PMID: 34777284 PMCID: PMC8581549 DOI: 10.3389/fmicb.2021.733344] [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: 06/30/2021] [Accepted: 09/22/2021] [Indexed: 11/30/2022] Open
Abstract
Nucleoid-associated proteins (NAPs) or histone-like proteins (HLPs) are DNA-binding proteins present in bacteria that play an important role in nucleoid architecture and gene regulation. NAPs affect bacterial nucleoid organization via DNA bending, bridging, or forming aggregates. EbfC is a nucleoid-associated protein identified first in Borrelia burgdorferi, belonging to YbaB/EbfC family of NAPs capable of binding and altering DNA conformation. YbaB, an ortholog of EbfC found in Escherichia coli and Haemophilus influenzae, also acts as a transcriptional regulator. YbaB has a novel tweezer-like structure and binds DNA as homodimers. The homologs of YbaB are found in almost all bacterial species, suggesting a conserved function, yet the physiological role of YbaB protein in many bacteria is not well understood. In this study, we characterized the YbaB/EbfC family DNA-binding protein in Caulobacter crescentus. C. crescentus has one YbaB/EbfC family gene annotated in the genome (YbaBCc) and it shares 41% sequence identity with YbaB/EbfC family NAPs. Computational modeling revealed tweezer-like structure of YbaBCc, a characteristic of YbaB/EbfC family of NAPs. N-terminal–CFP tagged YbaBCc localized with the nucleoid and is able to compact DNA. Unlike B. burgdorferi EbfC protein, YbaBCc protein is a non-specific DNA-binding protein in C. crescentus. Moreover, YbaBCc shields DNA against enzymatic degradation. Collectively, our findings reveal that YbaBCc is a small histone-like protein and may play a role in bacterial chromosome structuring and gene regulation in C. crescentus.
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Affiliation(s)
- Parul Pal
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Malvika Modi
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Shashank Ravichandran
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - Ragothaman M Yennamalli
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
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7
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Agarwal N, Jaiswal N, Gulati K, Gangele K, Nagar N, Kumar D, Poluri KM. Molecular Insights into Conformational Heterogeneity and Enhanced Structural Integrity of Helicobacter pylori DNA Binding Protein Hup at Low pH. Biochemistry 2021; 60:3236-3252. [PMID: 34665609 DOI: 10.1021/acs.biochem.1c00395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The summarized amalgam of internal relaxation modulations and external forces like pH, temperature, and solvent conditions determine the protein structure, stability, and function. In a free-energy landscape, although conformers are arranged in vertical hierarchy, there exist several adjacent parallel sets with conformers occupying equivalent energy cleft. Such conformational states are pre-requisites for the functioning of proteins that have oscillating environmental conditions. As these conformational changes have utterly small re-arrangements, nuclear magnetic resonance (NMR) spectroscopy is unique in elucidating the structure-dynamics-stability-function relationships for such conformations. Helicobacter pylori survives and causes gastric cancer at extremely low pH also. However, least is known as to how the genome of the pathogen is protected from reactive oxygen species (ROS) scavenging in the gut at low pH under acidic stress. In the current study, biophysical characteristics of H. pylori DNA binding protein (Hup) have been elucidated at pH 2 using a combination of circular dichroism, fluorescence, NMR spectroscopy, and molecular dynamics simulations. Interestingly, the protein was found to have conserved structural features, differential backbone dynamics, enhanced stability, and DNA binding ability at low pH as well. In summary, the study suggests the partaking of Hup protein even at low pH in DNA protection for maintaining the genome integrity.
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Affiliation(s)
- Nipanshu Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nancy Jaiswal
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Khushboo Gulati
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Krishnakant Gangele
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nupur Nagar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Krishna Mohan Poluri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India.,Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
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8
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Gene Expression Analysis by Reverse Transcription Quantitative PCR. Methods Mol Biol 2021. [PMID: 33765310 DOI: 10.1007/978-1-0716-1302-3_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
The reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a rapid detection technology that allows the amplification and quantification of specific RNA transcripts. RT-qPCR has increasingly been adopted for the detection and quantification of H. pylori across a range of sample types and applications. In addition, it is widely used to monitor host gene expression in cells and tissues in response to H. pylori infection . Outlined here is a two-step protocol that can be employed to analyze gene expression in H. pylori or H. pylori-infected samples.
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9
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Jenkins J, Mantell J, Neal C, Gholinia A, Verkade P, Nobbs AH, Su B. Antibacterial effects of nanopillar surfaces are mediated by cell impedance, penetration and induction of oxidative stress. Nat Commun 2020; 11:1626. [PMID: 32242015 PMCID: PMC7118135 DOI: 10.1038/s41467-020-15471-x] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/04/2020] [Indexed: 01/02/2023] Open
Abstract
Some insects, such as dragonflies, have evolved nanoprotrusions on their wings that rupture bacteria on contact. This has inspired the design of antibacterial implant surfaces with insect-wing mimetic nanopillars made of synthetic materials. Here, we characterise the physiological and morphological effects of mimetic titanium nanopillars on bacteria. The nanopillars induce deformation and penetration of the Gram-positive and Gram-negative bacterial cell envelope, but do not rupture or lyse bacteria. They can also inhibit bacterial cell division, and trigger production of reactive oxygen species and increased abundance of oxidative stress proteins. Our results indicate that nanopillars' antibacterial activities may be mediated by oxidative stress, and do not necessarily require bacterial lysis.
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Affiliation(s)
- J Jenkins
- Bristol Dental School, University of Bristol, Bristol, UK
| | - J Mantell
- School of Biochemistry, University of Bristol, Bristol, UK
| | - C Neal
- School of Biochemistry, University of Bristol, Bristol, UK
| | - A Gholinia
- School of Materials Science, University of Manchester, Manchester, UK
| | - P Verkade
- School of Biochemistry, University of Bristol, Bristol, UK
| | - A H Nobbs
- Bristol Dental School, University of Bristol, Bristol, UK.
| | - B Su
- Bristol Dental School, University of Bristol, Bristol, UK.
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10
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Pepe S, Scarlato V, Roncarati D. The Helicobacter pylori HspR-Modulator CbpA Is a Multifunctional Heat-Shock Protein. Microorganisms 2020; 8:microorganisms8020251. [PMID: 32069975 PMCID: PMC7074700 DOI: 10.3390/microorganisms8020251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/31/2020] [Accepted: 02/11/2020] [Indexed: 12/24/2022] Open
Abstract
The medically important human pathogen Helicobacter pylori relies on a collection of highly conserved heat-shock and chaperone proteins to preserve the integrity of cellular polypeptides and to control their homeostasis in response to external stress and changing environmental conditions. Among this set of chaperones, the CbpA protein has been shown to play a regulatory role in heat-shock gene regulation by directly interacting with the master stress-responsive repressor HspR. Apart from this regulatory role, little is known so far about CbpA functional activities. Using biochemistry and molecular biology approaches, we have started the in vitro functional characterization of H. pylori CbpA. Specifically, we show that CbpA is a multifunctional protein, being able to bind DNA and to stimulate the ATPase activity of the major chaperone DnaK. In addition, we report a preliminary observation suggesting that CbpA DNA-binding activity can be affected by the direct interaction with the heat-shock master repressor HspR, supporting the hypothesis of a reciprocal crosstalk between these two proteins. Thus, our work defines novel functions for H. pylori CbpA and stimulates further studies aimed at the comprehension of the complex regulatory interplay among chaperones and heat-shock transcriptional regulators.
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Affiliation(s)
| | - Vincenzo Scarlato
- Correspondence: (V.S.); (D.R.); Tel.: +39-051-2094204 (V.S.); +39-051-2099320 (D.R.)
| | - Davide Roncarati
- Correspondence: (V.S.); (D.R.); Tel.: +39-051-2094204 (V.S.); +39-051-2099320 (D.R.)
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11
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Guan Z, Wang Y, Gao L, Zhang W, Lu X. Effects of the histone-like protein HU on cellulose degradation and biofilm formation of Cytophaga hutchinsonii. Appl Microbiol Biotechnol 2018; 102:6593-6611. [PMID: 29876607 DOI: 10.1007/s00253-018-9071-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/26/2018] [Accepted: 04/29/2018] [Indexed: 01/23/2023]
Abstract
Cytophaga hutchinsonii, belonging to Bacteroidetes, is speculated to use a novel cell-contact mode to digest cellulose. In this study, we identified a histone-like protein HU, CHU_2750, in C. hutchinsonii, whose transcription could be induced by crystalline but not amorphous cellulose. We constructed a CHU_2750-deleted mutant and expressed CHU_2750 in Escherichia coli to study the gene's functions. Our results showed that although the deletion of CHU_2750 was not lethal to C. hutchinsonii, the mutant displayed an abnormal filamentous morphology, loose nucleoid, and obvious defects in the degradation of crystalline cellulose and cell motility. Further study indicated that the mutant displayed significantly decreased cell surface and intracellular endoglucanase activities but with β-glucosidase activities similar to the wild-type strain. Analyses by real-time quantitative PCR revealed that the transcription levels of many genes involved in cellulose degradation and/or cell motility were significantly downregulated in the mutant. In addition, we found that CHU_2750 was important for biofilm formation of C. hutchinsonii. The main extracellular components of the biofilm were analyzed, and the results showed that the mutant yielded significantly less exopolysaccharide but more extracellular DNA and protein than the wild-type strain. Collectively, our findings demonstrated that CHU_2750 is important for cellulose degradation, cell motility, and biofilm formation of C. hutchinsonii by modulating transcription of certain related genes, and it is the first identified transcriptional regulator in these processes of C. hutchinsonii. Our study shed more light on the mechanisms of cellulose degradation, cell motility, and biofilm formation by C. hutchinsonii.
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Affiliation(s)
- Zhiwei Guan
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China.,School of Life Science, Qilu Normal University, Jinan, 250200, China
| | - Ying Wang
- Central Laboratory, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, 223300, China
| | - Lijuan Gao
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China
| | - Weican Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China
| | - Xuemei Lu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China.
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12
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Álvarez A, Toledo H. The histone-like protein HU has a role in gene expression during the acid adaptation response in Helicobacter pylori. Helicobacter 2017; 22. [PMID: 28244177 DOI: 10.1111/hel.12381] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Gastritis, ulcers, and gastric malignancy have been linked to human gastric epithelial colonization by Helicobacter pylori. Characterization of the mechanisms by which H. pylori adapts to the human stomach environment is of crucial importance to understand H. pylori pathogenesis. MATERIAL AND METHODS In an effort to extend our knowledge of these mechanisms, we used proteomic analysis and qRT-PCR to characterize the role of the histone-like protein HU in the response of H. pylori to low pH. RESULTS Proteomic analysis revealed that genes involved in chemotaxis, oxidative stress, or metabolism are under control of the HU protein. Also, expression of the virulence factors Ggt and NapA is affected by the null mutation of hup gene both at neutral and acid pH, as evidenced by qRT-PCR analysis. CONCLUSIONS Those results showed that H. pylori gene expression is altered by shift to low pH, thus confirming that acid exposure leads to profound changes in genomic expression, and suggest that the HU protein is a regulator that may help the bacterium adapt to the acid stress. In accordance with previous reports, we found that the HU protein participates in gene expression regulation when the microorganism is exposed to acid stress. Such transcriptional regulation underlies protein accumulation in the H. pylori cell.
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Affiliation(s)
- Alhejandra Álvarez
- Laboratory of Molecular Microbiology, Department of Molecular and Cellular Biology, Faculty of Medicine, ICBM, University of Chile, Santiago, Chile
| | - Héctor Toledo
- Laboratory of Molecular Microbiology, Department of Molecular and Cellular Biology, Faculty of Medicine, ICBM, University of Chile, Santiago, Chile
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13
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De la Cruz MA, Ares MA, von Bargen K, Panunzi LG, Martínez-Cruz J, Valdez-Salazar HA, Jiménez-Galicia C, Torres J. Gene Expression Profiling of Transcription Factors of Helicobacter pylori under Different Environmental Conditions. Front Microbiol 2017; 8:615. [PMID: 28443084 PMCID: PMC5385360 DOI: 10.3389/fmicb.2017.00615] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterium that colonizes the human gastric mucosa and causes peptic ulcers and gastric carcinoma. H. pylori strain 26695 has a small genome (1.67 Mb), which codes for few known transcriptional regulators that control bacterial metabolism and virulence. We analyzed by qRT-PCR the expression of 16 transcriptional regulators in H. pylori 26695, including the three sigma factors under different environmental conditions. When bacteria were exposed to acidic pH, urea, nickel, or iron, the sigma factors were differentially expressed with a particularly strong induction of fliA. The regulatory genes hrcA, hup, and crdR were highly induced in the presence of urea, nickel, and iron. In terms of biofilm formation fliA, flgR, hp1021, fur, nikR, and crdR were induced in sessile bacteria. Transcriptional expression levels of rpoD, flgR, hspR, hp1043, and cheY were increased in contact with AGS epithelial cells. Kanamycin, chloramphenicol, and tetracycline increased or decreased expression of regulatory genes, showing that these antibiotics affect the transcription of H. pylori. Our data indicate that environmental cues which may be present in the human stomach modulate H. pylori transcription.
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Affiliation(s)
- Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
| | | | - Leonardo G Panunzi
- CNRS UMR7280, Inserm, U1104, Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2Marseille, France
| | - Jessica Martínez-Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
| | - Hilda A Valdez-Salazar
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
| | - César Jiménez-Galicia
- Laboratorio Clínico, Unidad Médica de Alta Especialidad, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro SocialMexico City, Mexico
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Hammel M, Amlanjyoti D, Reyes FE, Chen JH, Parpana R, Tang HYH, Larabell CA, Tainer JA, Adhya S. HU multimerization shift controls nucleoid compaction. SCIENCE ADVANCES 2016; 2:e1600650. [PMID: 27482541 PMCID: PMC4966879 DOI: 10.1126/sciadv.1600650] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 06/14/2016] [Indexed: 05/05/2023]
Abstract
Molecular mechanisms controlling functional bacterial chromosome (nucleoid) compaction and organization are surprisingly enigmatic but partly depend on conserved, histone-like proteins HUαα and HUαβ and their interactions that span the nanoscale and mesoscale from protein-DNA complexes to the bacterial chromosome and nucleoid structure. We determined the crystal structures of these chromosome-associated proteins in complex with native duplex DNA. Distinct DNA binding modes of HUαα and HUαβ elucidate fundamental features of bacterial chromosome packing that regulate gene transcription. By combining crystal structures with solution x-ray scattering results, we determined architectures of HU-DNA nucleoproteins in solution under near-physiological conditions. These macromolecular conformations and interactions result in contraction at the cellular level based on in vivo imaging of native unlabeled nucleoid by soft x-ray tomography upon HUβ and ectopic HUα38 expression. Structural characterization of charge-altered HUαα-DNA complexes reveals an HU molecular switch that is suitable for condensing nucleoid and reprogramming noninvasive Escherichia coli into an invasive form. Collective findings suggest that shifts between networking and cooperative and noncooperative DNA-dependent HU multimerization control DNA compaction and supercoiling independently of cellular topoisomerase activity. By integrating x-ray crystal structures, x-ray scattering, mutational tests, and x-ray imaging that span from protein-DNA complexes to the bacterial chromosome and nucleoid structure, we show that defined dynamic HU interaction networks can promote nucleoid reorganization and transcriptional regulation as efficient general microbial mechanisms to help synchronize genetic responses to cell cycle, changing environments, and pathogenesis.
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Affiliation(s)
- Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Corresponding author. (M.H.); (J.A.T.)
| | - Dhar Amlanjyoti
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Francis E. Reyes
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jian-Hua Chen
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - Rochelle Parpana
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Henry Y. H. Tang
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Carolyn A. Larabell
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94143, USA
| | - John A. Tainer
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
- Corresponding author. (M.H.); (J.A.T.)
| | - Sankar Adhya
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Two-component system YvqEC-dependent bacterial resistance against vancomycin in Bacillus thuringiensis. Antonie van Leeuwenhoek 2015; 108:365-76. [PMID: 26025304 DOI: 10.1007/s10482-015-0489-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/19/2015] [Indexed: 02/06/2023]
Abstract
YvqEC is one of the two-component signal transduction systems that may respond to cell envelope stress and enable cells to adjust multiple cellular functions. It consists of a histidine kinase YvqE and a response regulator YvqC. In this study, we separately constructed a single gene mutant ΔyvqE and a double gene mutant ΔyvqEC in Bacillus thuringiensis BMB171 through a homing endonucleases I-SceI mediated markerless gene deletion method. We found that the deletion of either yvqE or yvqEC weakened the resistance of B. thuringiensis against vancomycin. We also identified nine operons that may be involved in the cellular metabolism regulated by YvqC. This study not only enriches our understanding of bacterial resistance mechanisms against vancomycin, but also helps investigate the functions of YvqEC.
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Bacterial histone-like proteins: roles in stress resistance. Curr Genet 2015; 61:489-92. [DOI: 10.1007/s00294-015-0478-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 01/30/2015] [Indexed: 12/16/2022]
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