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Besrour-Aouam N, de Los Rios V, Hernández-Alcántara AM, Mohedano ML, Najjari A, López P, Ouzari HI. Proteomic and in silico analyses of dextran synthesis influence on Leuconostoc lactis AV1n adaptation to temperature change. Front Microbiol 2023; 13:1077375. [PMID: 36713162 PMCID: PMC9875047 DOI: 10.3389/fmicb.2022.1077375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023] Open
Abstract
Leuconostoc lactis is found in vegetables, fruits, and meat and is used by the food industry in the preparation of dairy products, wines, and sugars. We have previously demonstrated that the dextransucrase of Lc. lactis (DsrLL) AV1n produces a high-molecular-weight dextran from sucrose, indicating its potential use as a dextran-forming starter culture. We have also shown that this bacterium was able to produce 10-fold higher levels of dextran at 20°C than at 37°C, at the former temperature accompanied by an increase in dsrLL gene expression. However, the general physiological response of Lc. lactis AV1n to cold temperature in the presence of sucrose, leading to increased production of dextran, has not been yet investigated. Therefore, we have used a quantitative proteomics approach to investigate the cold temperature-induced changes in the proteomic profile of this strain in comparison to its proteomic response at 37°C. In total, 337 proteins were found to be differentially expressed at the applied significance criteria (adjusted p-value ≤ 0.05, FDR 5%, and with a fold-change ≥ 1.5 or ≤ 0.67) with 204 proteins overexpressed, among which 13% were involved in protein as well as cell wall, and envelope component biosynthesis including DsrLL. Proteins implicated in cold stress were expressed at a high level at 20°C and possibly play a role in the upregulation of DsrLL, allowing the efficient synthesis of the protein essential for its adaptation to cold. Post-transcriptional regulation of DsrLL expression also seems to take place through the interplay of exonucleases and endonucleases overexpressed at 20°C, which would influence the half-life of the dsrLL transcript. Furthermore, the mechanism of cold resistance of Lc. lactis AV1n seems to be also based on energy saving through a decrease in growth rate mediated by a decrease in carbohydrate metabolism and its orientation toward the production pathways for storage molecules. Thus, this better understanding of the responses to low temperature and mechanisms for environmental adaptation of Lc. lactis could be exploited for industrial use of strains belonging to this species.
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Affiliation(s)
- Norhane Besrour-Aouam
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain,Laboratoire Microorganismes et Biomolécules Actives (LR03ES03), Faculté des Sciences de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Vivian de Los Rios
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | | | - Mᵃ Luz Mohedano
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | - Afef Najjari
- Laboratoire Microorganismes et Biomolécules Actives (LR03ES03), Faculté des Sciences de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Paloma López
- Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain,*Correspondence: Paloma López,
| | - Hadda-Imene Ouzari
- Laboratoire Microorganismes et Biomolécules Actives (LR03ES03), Faculté des Sciences de Tunis, Université Tunis El Manar, Tunis, Tunisia,Hadda-Imene Ouzari,
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2
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Li G, Kuijer HNJ, Yang X, Liu H, Shen C, Shi J, Betts N, Tucker MR, Liang W, Waugh R, Burton RA, Zhang D. MADS1 maintains barley spike morphology at high ambient temperatures. NATURE PLANTS 2021; 7:1093-1107. [PMID: 34183784 DOI: 10.1038/s41477-021-00957-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 06/02/2021] [Indexed: 05/05/2023]
Abstract
Temperature stresses affect plant phenotypic diversity. The developmental stability of the inflorescence, required for reproductive success, is tightly regulated by the interplay of genetic and environmental factors. However, the mechanisms underpinning how plant inflorescence architecture responds to temperature are largely unknown. We demonstrate that the barley SEPALLATA MADS-box protein HvMADS1 is responsible for maintaining an unbranched spike architecture at high temperatures, while the loss-of-function mutant forms a branched inflorescence-like structure. HvMADS1 exhibits increased binding to target promoters via A-tract CArG-box motifs, which change conformation with temperature. Target genes for high-temperature-dependent HvMADS1 activation are predominantly associated with inflorescence differentiation and phytohormone signalling. HvMADS1 directly regulates the cytokinin-degrading enzyme HvCKX3 to integrate temperature response and cytokinin homeostasis, which is required to repress meristem cell cycle/division. Our findings reveal a mechanism by which genetic factors direct plant thermomorphogenesis, extending the recognized role of plant MADS-box proteins in floral development.
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Affiliation(s)
- Gang Li
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia.
- School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang, China.
| | - Hendrik N J Kuijer
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
| | - Xiujuan Yang
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
| | - Huiran Liu
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chaoqun Shen
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jin Shi
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Natalie Betts
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
| | - Matthew R Tucker
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Robbie Waugh
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
- James Hutton Institute, Dundee, UK
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, UK
| | - Rachel A Burton
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia
| | - Dabing Zhang
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Waite Campus, Glen Osmond, South Australia, Australia.
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
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3
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Pasqua M, Grossi M, Zennaro A, Fanelli G, Micheli G, Barras F, Colonna B, Prosseda G. The Varied Role of Efflux Pumps of the MFS Family in the Interplay of Bacteria with Animal and Plant Cells. Microorganisms 2019; 7:microorganisms7090285. [PMID: 31443538 PMCID: PMC6780985 DOI: 10.3390/microorganisms7090285] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 12/20/2022] Open
Abstract
Efflux pumps represent an important and large group of transporter proteins found in all organisms. The importance of efflux pumps resides in their ability to extrude a wide range of antibiotics, resulting in the emergence of multidrug resistance in many bacteria. Besides antibiotics, multidrug efflux pumps can also extrude a large variety of compounds: Bacterial metabolites, plant-produced compounds, quorum-sensing molecules, and virulence factors. This versatility makes efflux pumps relevant players in interactions not only with other bacteria, but also with plant or animal cells. The multidrug efflux pumps belonging to the major facilitator superfamily (MFS) are widely distributed in microbial genomes and exhibit a large spectrum of substrate specificities. Multidrug MFS efflux pumps are present either as single-component transporters or as tripartite complexes. In this review, we will summarize how the multidrug MFS efflux pumps contribute to the interplay between bacteria and targeted host cells, with emphasis on their role in bacterial virulence, in the colonization of plant and animal host cells and in biofilm formation. We will also address the complexity of these interactions in the light of the underlying regulatory networks required for the effective activation of efflux pump genes.
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Affiliation(s)
- Martina Pasqua
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Milena Grossi
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Alessandro Zennaro
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Giulia Fanelli
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche (CNR), P.le A. Moro 5, 00185 Roma, Italy
| | - Frederic Barras
- Département de Microbiologie, Institut Pasteur, 75015 Paris, France
- Équipe de Recherche Labellisée (ERL) Microbiology, Centre National de la Recherche Scientifique (CNRS), 13009 Marseille, France
| | - Bianca Colonna
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy
| | - Gianni Prosseda
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Via dei Sardi 70, 00185 Rome, Italy.
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Durano D, Lukacs A, Di Felice F, Micheli G, Camilloni G. A novel role for Nhp6 proteins in histone gene regulation in Saccharomyces cerevisiae. Int J Biochem Cell Biol 2017; 83:76-83. [DOI: 10.1016/j.biocel.2016.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 10/20/2022]
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One Gene and Two Proteins: a Leaderless mRNA Supports the Translation of a Shorter Form of the Shigella VirF Regulator. mBio 2016; 7:mBio.01860-16. [PMID: 27834204 PMCID: PMC5101355 DOI: 10.1128/mbio.01860-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
VirF, an AraC-like activator, is required to trigger a regulatory cascade that initiates the invasive program of Shigella spp., the etiological agents of bacillary dysentery in humans. VirF expression is activated upon entry into the host and depends on many environmental signals. Here, we show that the virF mRNA is translated into two proteins, the major form, VirF30 (30 kDa), and the shorter VirF21 (21 kDa), lacking the N-terminal segment. By site-specific mutagenesis and toeprint analysis, we identified the translation start sites of VirF30 and VirF21 and showed that the two different forms of VirF arise from differential translation. Interestingly, in vitro and in vivo translation experiments showed that VirF21 is also translated from a leaderless mRNA (llmRNA) whose 5′ end is at position +309/+310, only 1 or 2 nucleotides upstream of the ATG84 start codon of VirF21. The llmRNA is transcribed from a gene-internal promoter, which we identified here. Functional analysis revealed that while VirF30 is responsible for activation of the virulence system, VirF21 negatively autoregulates virF expression itself. Since VirF21 modulates the intracellular VirF levels, this suggests that transcription of the llmRNA might occur when the onset of the virulence program is not required. We speculate that environmental cues, like stress conditions, may promote changes in virF mRNA transcription and preferential translation of llmRNA. Shigella spp. are a major cause of dysentery in humans. In bacteria of this genus, the activation of the invasive program involves a multitude of signals that act on all layers of the gene regulatory hierarchy. By controlling the essential genes for host cell invasion, VirF is the key regulator of the switch from the noninvasive to the invasive phenotype. Here, we show that the Shigella virF gene encodes two proteins of different sizes, VirF30 and VirF21, that are functionally distinct. The major form, VirF30, activates the genes necessary for virulence, whereas the minor VirF21, which shares the C-terminal two-thirds of VirF30, negatively autoregulates virF expression itself. VirF21 is transcribed from a newly identified gene-internal promoter and, moreover, is translated from an unusual leaderless mRNA. The identification of a new player in regulation adds complexity to the regulation of the Shigella invasive process and may help development of new therapies for shigellosis.
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Di Martino ML, Falconi M, Micheli G, Colonna B, Prosseda G. The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle. Front Mol Biosci 2016; 3:61. [PMID: 27747215 PMCID: PMC5041530 DOI: 10.3389/fmolb.2016.00061] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/15/2016] [Indexed: 12/20/2022] Open
Abstract
Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis.
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Affiliation(s)
- Maria Letizia Di Martino
- Dipartimento di Biologia e Biotecnologie C. Darwin, Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma Roma, Italy
| | - Maurizio Falconi
- Laboratorio di Genetica Molecolare e dei Microrganismi, Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino Camerino, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia Molecolari, Consilglio Nazionale Delle Richerche Roma, Italy
| | - Bianca Colonna
- Dipartimento di Biologia e Biotecnologie C. Darwin, Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma Roma, Italy
| | - Gianni Prosseda
- Dipartimento di Biologia e Biotecnologie C. Darwin, Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza Università di Roma Roma, Italy
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7
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Leuzzi A, Di Martino ML, Campilongo R, Falconi M, Barbagallo M, Marcocci L, Pietrangeli P, Casalino M, Grossi M, Micheli G, Colonna B, Prosseda G. Multifactor Regulation of the MdtJI Polyamine Transporter in Shigella. PLoS One 2015; 10:e0136744. [PMID: 26313003 PMCID: PMC4636849 DOI: 10.1371/journal.pone.0136744] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/06/2015] [Indexed: 01/19/2023] Open
Abstract
The polyamine profile of Shigella, the etiological agent of bacillary dysentery in humans, differs markedly from that of E. coli, its innocuous commensal ancestor. Pathoadaptive mutations such as the loss of cadaverine and the increase of spermidine favour the full expression of the virulent phenotype of Shigella. Spermidine levels affect the expression of the MdtJI complex, a recently identified efflux pump belonging to the small multi-drug resistance family of transporters. In the present study, we have addressed the regulation of the mdtJI operon in Shigella by asking which factors influence its expression as compared to E. coli. In particular, after identifying the mdtJI promoter by primer extension analysis, in vivo transcription assays and gel-retardation experiments were carried out to get insight on the silencing of mdtJI in E. coli. The results indicate that H-NS, a major nucleoid protein, plays a key role in repressing the mdtJI operon by direct binding to the regulatory region. In the Shigella background mdtJI expression is increased by the high levels of spermidine typically found in this microorganism and by VirF, the plasmid-encoded regulator of the Shigella virulence regulatory cascade. We also show that the expression of mdtJI is stimulated by bile components. Functional analyses reveal that MdtJI is able to promote the excretion of putrescine, the spermidine precursor. This leads us to consider the MdtJI complex as a possible safety valve allowing Shigella to maintain spermidine to a level optimally suited to survival within infected macrophages and, at the same time, prevent toxicity due to spermidine over-accumulation.
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Affiliation(s)
- Adriano Leuzzi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maria Letizia Di Martino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Rosaria Campilongo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maurizio Falconi
- Laboratorio di Genetica Molecolare e dei Microrganismi, Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via Gentile III da Varano, Camerino, Italy
| | - Marialuisa Barbagallo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Lucia Marcocci
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Paola Pietrangeli
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Mariassunta Casalino
- Dipartimento di Scienze, Università Roma Tre, Viale G. Marconi 446, 00146, Roma, Italy
| | - Milena Grossi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia molecolari CNR, P.le A. Moro 5, 00185, Roma, Italy
| | - Bianca Colonna
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gianni Prosseda
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
- * E-mail:
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8
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Campilongo R, Di Martino ML, Marcocci L, Pietrangeli P, Leuzzi A, Grossi M, Casalino M, Nicoletti M, Micheli G, Colonna B, Prosseda G. Molecular and functional profiling of the polyamine content in enteroinvasive E. coli : looking into the gap between commensal E. coli and harmful Shigella. PLoS One 2014; 9:e106589. [PMID: 25192335 PMCID: PMC4156367 DOI: 10.1371/journal.pone.0106589] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 07/31/2014] [Indexed: 11/19/2022] Open
Abstract
Polyamines are small molecules associated with a wide variety of physiological functions. Bacterial pathogens have developed subtle strategies to exploit polyamines or manipulate polyamine-related processes to optimize fitness within the host. During the transition from its innocuous E. coli ancestor, Shigella, the aetiological agent of bacillary dysentery, has undergone drastic genomic rearrangements affecting the polyamine profile. A pathoadaptation process involving the speG gene and the cad operon has led to spermidine accumulation and loss of cadaverine. While a higher spermidine content promotes the survival of Shigella within infected macrophages, the lack of cadaverine boosts the pathogenic potential of the bacterium in host tissues. Enteroinvasive E. coli (EIEC) display the same pathogenicity process as Shigella, but have a higher infectious dose and a higher metabolic activity. Pathoadaption events affecting the cad locus have occurred also in EIEC, silencing cadaverine production. Since EIEC are commonly regarded as evolutionary intermediates between E. coli and Shigella, we investigated on their polyamine profile in order to better understand which changes have occurred along the path to pathogenicity. By functional and molecular analyses carried out in EIEC strains belonging to different serotypes, we show that speG has been silenced in one strain only, favouring resistance to oxidative stress conditions and survival within macrophages. At the same time, we observe that the content of spermidine and putrescine, a relevant intermediate in the synthesis of spermidine, is higher in all strains as compared to E. coli. This may represent an evolutionary response to the lack of cadaverine. Indeed, restoring cadaverine synthesis decreases the expression of the speC gene, whose product affects putrescine production. In the light of these results, we discuss the possible impact of pathoadaptation events on the evolutionary emergence of a polyamine profile favouring to the pathogenic lifestyle of Shigella and EIEC.
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Affiliation(s)
- Rosaria Campilongo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Maria Letizia Di Martino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
- Dipartimento di Scienze, Università Roma Tre, Roma, Italy
| | - Lucia Marcocci
- Dipartimento di Biochimica, Sapienza Università di Roma, Roma, Italy
| | - Paola Pietrangeli
- Dipartimento di Biochimica, Sapienza Università di Roma, Roma, Italy
| | - Adriano Leuzzi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Milena Grossi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
| | | | - Mauro Nicoletti
- Dipartimento di Scienze Sperimentali e Cliniche, Università G. D'Annunzio, Chieti, Italy
| | - Gioacchino Micheli
- Istituto di Biologia, Medicina Molecolare e NanoBiotecnologie, Consiglio Nazionale delle Ricerche, Roma, Italy
| | - Bianca Colonna
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Gianni Prosseda
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Roma, Italy
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Abstract
Bending of double-stranded DNA (dsDNA) is associated with many important biological processes such as DNA-protein recognition and DNA packaging into nucleosomes. Thermodynamics of dsDNA bending has been studied by a method called cyclization which relies on DNA ligase to covalently join short sticky ends of a dsDNA. However, ligation efficiency can be affected by many factors that are not related to dsDNA looping such as the DNA structure surrounding the joined sticky ends, and ligase can also affect the apparent looping rate through mechanisms such as nonspecific binding. Here, we show how to measure dsDNA looping kinetics without ligase by detecting transient DNA loop formation by FRET (Fluorescence Resonance Energy Transfer). dsDNA molecules are constructed using a simple PCR-based protocol with a FRET pair and a biotin linker. The looping probability density known as the J factor is extracted from the looping rate and the annealing rate between two disconnected sticky ends. By testing two dsDNAs with different intrinsic curvatures, we show that the J factor is sensitive to the intrinsic shape of the dsDNA.
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Affiliation(s)
- Tung T Le
- School of Physics, Georgia Institute of Technology
| | - Harold D Kim
- School of Physics, Georgia Institute of Technology;
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10
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Le TT, Kim HD. Measuring shape-dependent looping probability of DNA. Biophys J 2013; 104:2068-76. [PMID: 23663850 DOI: 10.1016/j.bpj.2013.03.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 03/14/2013] [Accepted: 03/18/2013] [Indexed: 01/06/2023] Open
Abstract
Recently, several studies have shown that short doubled-stranded DNA (dsDNA) loops more readily than the wormlike chain model predicts. In most of these experiments, the intrinsic bendedness of dsDNA, which in theory can dramatically influence looping dynamics, was either avoided or unaccounted for. To investigate the effect of the shape of dsDNA on looping dynamics, we characterized the shapes of several synthetic dsDNA molecules of equal length but different sequences using gel electrophoresis. We then measured their looping rates using a FRET (Förster resonance energy transfer)-based assay and extracted the looping probability density known as the J factor (jM). We also used, for comparison, several dinucleotide angular parameter sets derived from the observed electrophoretic mobility to compute the jM predicted by the wormlike chain model. Although we found a strong correlation between curvature and jM, the measured jM was higher than most dinucleotide model predictions. This result suggests that it is difficult to reconcile the looping probability with the observed gel mobility within the wormlike chain model and underscores the importance of determining the intrinsic shape of dsDNA for proper theoretical analysis.
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Affiliation(s)
- Tung T Le
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
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Muiño JM, Smaczniak C, Angenent GC, Kaufmann K, van Dijk ADJ. Structural determinants of DNA recognition by plant MADS-domain transcription factors. Nucleic Acids Res 2013; 42:2138-46. [PMID: 24275492 PMCID: PMC3936718 DOI: 10.1093/nar/gkt1172] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Plant MADS-domain transcription factors act as key regulators of many developmental processes. Despite the wealth of information that exists about these factors, the mechanisms by which they recognize their cognate DNA-binding site, called CArG-box (consensus CCW6GG), and how different MADS-domain proteins achieve DNA-binding specificity, are still largely unknown. We used information from in vivo ChIP-seq experiments, in vitro DNA-binding data and evolutionary conservation to address these important questions. We found that structural characteristics of the DNA play an important role in the DNA binding of plant MADS-domain proteins. The central region of the CArG-box largely resembles a structural motif called ‘A-tract’, which is characterized by a narrow minor groove and may assist bending of the DNA by MADS-domain proteins. Periodically spaced A-tracts outside the CArG-box suggest additional roles for this structure in the process of DNA binding of these transcription factors. Structural characteristics of the CArG-box not only play an important role in DNA-binding site recognition of MADS-domain proteins, but also partly explain differences in DNA-binding specificity of different members of this transcription factor family and their heteromeric complexes.
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Affiliation(s)
- Jose M Muiño
- Bioscience, Plant Research International, Wageningen, PO Box 619, 6700 AP, The Netherlands, Laboratory of Bioinformatics, Wageningen University, PO Box 569, 6700 AN Wageningen, The Netherlands, Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin D-14195, Germany, Laboratory of Molecular Biology, Wageningen University, Wageningen, PO Box 633, 6700 AP, The Netherlands and Biometris, Wageningen University and Research Centre, Wageningen, PO Box 100, 6700 AC, The Netherlands
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Seghezzi N, Amar P, Koebmann B, Jensen PR, Virolle MJ. The construction of a library of synthetic promoters revealed some specific features of strong Streptomyces promoters. Appl Microbiol Biotechnol 2011; 90:615-23. [PMID: 21243353 DOI: 10.1007/s00253-010-3018-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 11/12/2010] [Accepted: 11/15/2010] [Indexed: 02/01/2023]
Abstract
Streptomyces are bacteria of industrial interest whose genome contains more than 73% of bases GC. In order to define, in these GC-rich bacteria, specific sequence features of strong promoters, a library of synthetic promoters of various sequence composition was constructed in Streptomyces. To do so, the sequences located upstream, between and downstream of the -35 and -10 consensus promoter sequences were completely randomized and some variability was introduced in the -35 (position 6) and -10 (positions 3, 4 and 5) hexamers recognized by the major vegetative sigma factor HrdB. The synthetic promoters were cloned into the promoter-probe plasmid pIJ487 just upstream of the promoter-less aphII gene that confers resistance to neomycin. This synthetic promoter library was transformed into Streptomyces lividans, and the resulting transformants were screened for their ability to grow in the presence of different concentrations of neomycin (20, 50, and 100 μgml(-1)). Promoter strengths varied up to 12-fold, in small increments of activity increase, as determined by reverse transcriptase-PCR. This collection of promoters of various strengths can be useful for the fine-tuning of gene expression in genetic engineering projects. Thirty-eight promoters were sequenced, and the sequences of the 14 weakest and 14 strongest promoters were compared using the WebLogo software with small sample correction. This comparison revealed that the -10 box, the -10 extended motif as well as the spacer of the strong Streptomyces promoters are more G rich than those of the weak promoters.
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Affiliation(s)
- Nicolas Seghezzi
- Institut de Génétique et Microbiologie, UMR8621 CNRS Université Paris Sud, 91405, Orsay, France
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