1
|
Qiao J, Borriss R, Sun K, Zhang R, Chen X, Liu Y, Liu Y. Research advances in the identification of regulatory mechanisms of surfactin production by Bacillus: a review. Microb Cell Fact 2024; 23:100. [PMID: 38566071 PMCID: PMC10988940 DOI: 10.1186/s12934-024-02372-7] [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: 11/16/2023] [Accepted: 03/18/2024] [Indexed: 04/04/2024] Open
Abstract
Surfactin is a cyclic hexalipopeptide compound, nonribosomal synthesized by representatives of the Bacillus subtilis species complex which includes B. subtilis group and its closely related species, such as B. subtilis subsp subtilis, B. subtilis subsp spizizenii, B. subtilis subsp inaquosorum, B. atrophaeus, B. amyloliquefaciens, B. velezensis (Steinke mSystems 6: e00057, 2021) It functions as a biosurfactant and signaling molecule and has antibacterial, antiviral, antitumor, and plant disease resistance properties. The Bacillus lipopeptides play an important role in agriculture, oil recovery, cosmetics, food processing and pharmaceuticals, but the natural yield of surfactin synthesized by Bacillus is low. This paper reviews the regulatory pathways and mechanisms that affect surfactin synthesis and release, highlighting the regulatory genes involved in the transcription of the srfAA-AD operon. The several ways to enhance surfactin production, such as governing expression of the genes involved in synthesis and regulation of surfactin synthesis and transport, removal of competitive pathways, optimization of media, and fermentation conditions were commented. This review will provide a theoretical platform for the systematic genetic modification of high-yielding strains of surfactin.
Collapse
Affiliation(s)
- Junqing Qiao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China
| | - Rainer Borriss
- Institute of Biology, Humboldt University Berlin, Berlin, Germany.
| | - Kai Sun
- College of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Rongsheng Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China
| | - Xijun Chen
- College of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Youzhou Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China.
| | - Yongfeng Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China.
| |
Collapse
|
2
|
Xia L, Wen J. Available strategies for improving the biosynthesis of surfactin: a review. Crit Rev Biotechnol 2023; 43:1111-1128. [PMID: 36001039 DOI: 10.1080/07388551.2022.2095252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/04/2022] [Indexed: 11/03/2022]
Abstract
Surfactin is an excellent biosurfactant with a wide range of application prospects in many industrial fields. However, its low productivity and high cost have largely limited its commercial applications. In this review, the pathways for surfactin synthesis in Bacillus strains are summarized and discussed. Further, the latest strategies for improving surfactin production, including: medium optimization, genome engineering methods (rational genetic engineering, genome reduction, and genome shuffling), heterologous synthesis, and the use of synthetic biology combined with metabolic engineering approaches to construct high-quality artificial cells for surfactin production using xylose, are described. Finally, the prospects for improving surfactin synthesis are discussed in detail.
Collapse
Affiliation(s)
- Li Xia
- Key Laboratory of Systems Bioengineering, Ministry of Education, Department of Biological Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
- National Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, People's Republic of China
- Frontier Science Center of the Ministry of Education, Tianjin University, Tianjin, People's Republic of China
| | - Jianping Wen
- Key Laboratory of Systems Bioengineering, Ministry of Education, Department of Biological Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China
- National Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin, People's Republic of China
- Frontier Science Center of the Ministry of Education, Tianjin University, Tianjin, People's Republic of China
| |
Collapse
|
3
|
Pilz M, Cavelius P, Qoura F, Awad D, Brück T. Lipopeptides development in cosmetics and pharmaceutical applications: A comprehensive review. Biotechnol Adv 2023; 67:108210. [PMID: 37460047 DOI: 10.1016/j.biotechadv.2023.108210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 07/05/2023] [Accepted: 07/09/2023] [Indexed: 07/25/2023]
Abstract
Lipopeptides are surface active, natural products of bacteria, fungi and green-blue algae origin, having diverse structures and functionalities. In analogy, a number of chemical synthesis techniques generated new designer lipopeptides with desirable features and functions. Lipopetides are self-assembly guided, supramolecular compounds which have the capacity of high-density presentation of the functional epitopes at the surface of the nanostructures. This feature contributes to their successful application in several industry sectors, including food, feed, personal care, and pharmaceutics. In this comprehensive review, the novel class of ribosomally synthesized lipopeptides is introduced alongside the more commonly occuring non-ribosomal lipopeptides. We highlight key representatives of the most researched as well as recently described lipopeptide families, with emphasis on structural features, self-assembly and associated functions. The common biological, chemical and hybrid production routes of lipopeptides, including prominent analogues and derivatives are also discussed. Furthermore, genetic engineering strategies aimed at increasing lipopeptide yields, diversity and biological activity are summarized and exemplified. With respect to application, this work mainly details the potential of lipopeptides in personal care and cosmetics industry as cleansing agents, moisturizer, anti-aging/anti-wrinkling, skin whitening and preservative agents as well as the pharmaceutical industry as anitimicrobial agents, vaccines, immunotherapy, and cancer drugs. Given that this review addresses human applications, we conclude on the topic of safety of lipopeptide formulations and their sustainable production.
Collapse
Affiliation(s)
- Melania Pilz
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Philipp Cavelius
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Farah Qoura
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Dania Awad
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany.
| | - Thomas Brück
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany.
| |
Collapse
|
4
|
Distinct Interaction Mechanism of RNAP and ResD and Distal Subsites for Transcription Activation of Nitrite Reductase in Bacillus subtilisψ. J Bacteriol 2021; 204:e0043221. [PMID: 34898263 DOI: 10.1128/jb.00432-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ResD-ResE signal transduction system plays a pivotal role in anaerobic nitrate respiration in Bacillus subtilis. The nasD operon encoding nitrite reductase is essential for nitrate respiration and is tightly controlled by the ResD response regulator. To understand the mechanism of ResD-dependent transcription activation of the nasD operon, we explored ResD-RNA polymerase (RNAP), ResD-DNA, and RNAP-DNA interactions required for nasD transcription. Full transcriptional activation requires the upstream promoter region where five molecules of ResD bind. The distal ResD-binding subsite at -87 to -84 partially overlaps a sequence similar to the consensus distal subsite of the upstream (UP) element with which the Escherichia coli C-terminal domain of the α subunit (αCTD) of RNAP interacts to stimulate transcription. We propose that interaction between αCTD and ResD at the promoter-distal site is essential for stimulating nasD transcription. Although nasD has an extended -10 promoter, it lacks a reasonable -35 element. Genetic analysis and structural simulations predicted that the absence of the -35 element might be compensated by interactions between σA and αCTD, and between αCTD and ResD at the promoter-proximal ResD-binding subsite. Thus, our work suggested that ResD likely participates in nasD transcription activation by binding to two αCTD subunits at the proximal and distal promoter sites, representing a unique configuration for transcription activation. IMPORTANCE A significant number of ResD-controlled genes have been identified and transcription regulatory pathways in which ResD participates have emerged. Nevertheless, the mechanism of how ResD activates transcription of different genes in a nucleotide sequence-specific manner has been less explored. This study suggested that among the five ResD-binding subsites in the promoter of the nasD operon, the promoter-proximal and -distal ResD-binding subsites play important roles in nasD activation by adapting different modes of protein-protein and protein-DNA interactions. The finding of a new-type of protein-promoter architecture provides insight into the understanding of transcription activation mechanisms controlled by transcription factors including the ubiquitous response regulators of two-component regulatory systems particularly in Gram-positive bacteria.
Collapse
|
5
|
Illigmann A, Thoma Y, Pan S, Reinhardt L, Brötz-Oesterhelt H. Contribution of the Clp Protease to Bacterial Survival and Mitochondrial Homoeostasis. Microb Physiol 2021; 31:260-279. [PMID: 34438398 DOI: 10.1159/000517718] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/07/2021] [Indexed: 11/19/2022]
Abstract
Fast adaptation to environmental changes ensures bacterial survival, and proteolysis represents a key cellular process in adaptation. The Clp protease system is a multi-component machinery responsible for protein homoeostasis, protein quality control, and targeted proteolysis of transcriptional regulators in prokaryotic cells and prokaryote-derived organelles of eukaryotic cells. A functional Clp protease complex consists of the tetradecameric proteolytic core ClpP and a hexameric ATP-consuming Clp-ATPase, several of which can associate with the same proteolytic core. Clp-ATPases confer substrate specificity by recognising specific degradation tags, and further selectivity is conferred by adaptor proteins, together allowing for a fine-tuned degradation process embedded in elaborate regulatory networks. This review focuses on the contribution of the Clp protease system to prokaryotic survival and summarises the current state of knowledge for exemplary bacteria in an increasing degree of interaction with eukaryotic cells. Starting from free-living bacteria as exemplified by a non-pathogenic and a pathogenic member of the Firmicutes, i.e., Bacillus subtilis and Staphylococcus aureus, respectively, we turn our attention to facultative and obligate intracellular bacterial pathogens, i.e., Mycobacterium tuberculosis, Listeria monocytogenes, and Chlamydia trachomatis, and conclude with mitochondria. Under stress conditions, the Clp protease system exerts its pivotal role in the degradation of damaged proteins and controls the timing and extent of the heat-shock response by regulatory proteolysis. Key regulators of developmental programmes like natural competence, motility, and sporulation are also under Clp proteolytic control. In many pathogenic species, the Clp system is required for the expression of virulence factors and essential for colonising the host. In accordance with its evolutionary origin, the human mitochondrial Clp protease strongly resembles its bacterial counterparts, taking a central role in protein quality control and homoeostasis, energy metabolism, and apoptosis in eukaryotic cells, and several cancer cell types depend on it for proliferation.
Collapse
Affiliation(s)
- Astrid Illigmann
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Yvonne Thoma
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Stefan Pan
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Laura Reinhardt
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Heike Brötz-Oesterhelt
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.,Cluster of Excellence Controlling Microbes to Fight Infection, University of Tübingen, Tübingen, Germany
| |
Collapse
|
6
|
Théatre A, Cano-Prieto C, Bartolini M, Laurin Y, Deleu M, Niehren J, Fida T, Gerbinet S, Alanjary M, Medema MH, Léonard A, Lins L, Arabolaza A, Gramajo H, Gross H, Jacques P. The Surfactin-Like Lipopeptides From Bacillus spp.: Natural Biodiversity and Synthetic Biology for a Broader Application Range. Front Bioeng Biotechnol 2021; 9:623701. [PMID: 33738277 PMCID: PMC7960918 DOI: 10.3389/fbioe.2021.623701] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/02/2021] [Indexed: 11/21/2022] Open
Abstract
Surfactin is a lipoheptapeptide produced by several Bacillus species and identified for the first time in 1969. At first, the biosynthesis of this remarkable biosurfactant was described in this review. The peptide moiety of the surfactin is synthesized using huge multienzymatic proteins called NonRibosomal Peptide Synthetases. This mechanism is responsible for the peptide biodiversity of the members of the surfactin family. In addition, on the fatty acid side, fifteen different isoforms (from C12 to C17) can be incorporated so increasing the number of the surfactin-like biomolecules. The review also highlights the last development in metabolic modeling and engineering and in synthetic biology to direct surfactin biosynthesis but also to generate novel derivatives. This large set of different biomolecules leads to a broad spectrum of physico-chemical properties and biological activities. The last parts of the review summarized the numerous studies related to the production processes optimization as well as the approaches developed to increase the surfactin productivity of Bacillus cells taking into account the different steps of its biosynthesis from gene transcription to surfactin degradation in the culture medium.
Collapse
Affiliation(s)
- Ariane Théatre
- Microbial Processes and Interactions, TERRA Teaching and Research Centre, Joint Research Unit BioEcoAgro, UMRt 1158, Gembloux Agro-Bio Tech, University of Liège, Avenue de la Faculté, Gembloux, Belgium
| | - Carolina Cano-Prieto
- Department of Pharmaceutical Biology, Pharmaceutical Institute, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Marco Bartolini
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias, Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Yoann Laurin
- Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Teaching and Research Centre, Joint Research Unit BioEcoAgro, UMRt 1158, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium.,Unité de Génie Enzymatique et Cellulaire UMR 7025 CNRS, Université de Picardie Jules Verne, Amiens, France
| | - Magali Deleu
- Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Teaching and Research Centre, Joint Research Unit BioEcoAgro, UMRt 1158, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium
| | - Joachim Niehren
- Inria Lille, and BioComputing Team of CRISTAL Lab (CNRS UMR 9189), Lille, France
| | - Tarik Fida
- Department of Pharmaceutical Biology, Pharmaceutical Institute, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Saïcha Gerbinet
- Chemical Engineering, Products, Environment, and Processes, University of Liège, Liège, Belgium
| | - Mohammad Alanjary
- Bioinformatics Group, Wageningen University, Wageningen, Netherlands
| | - Marnix H Medema
- Bioinformatics Group, Wageningen University, Wageningen, Netherlands
| | - Angélique Léonard
- Chemical Engineering, Products, Environment, and Processes, University of Liège, Liège, Belgium
| | - Laurence Lins
- Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Teaching and Research Centre, Joint Research Unit BioEcoAgro, UMRt 1158, Gembloux Agro-Bio Tech, Université de Liège, Gembloux, Belgium
| | - Ana Arabolaza
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias, Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo Gramajo
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias, Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Harald Gross
- Department of Pharmaceutical Biology, Pharmaceutical Institute, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Philippe Jacques
- Microbial Processes and Interactions, TERRA Teaching and Research Centre, Joint Research Unit BioEcoAgro, UMRt 1158, Gembloux Agro-Bio Tech, University of Liège, Avenue de la Faculté, Gembloux, Belgium
| |
Collapse
|
7
|
Théatre A, Hoste ACR, Rigolet A, Benneceur I, Bechet M, Ongena M, Deleu M, Jacques P. Bacillus sp.: A Remarkable Source of Bioactive Lipopeptides. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 181:123-179. [DOI: 10.1007/10_2021_182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
8
|
Wang C, Cao Y, Wang Y, Sun L, Song H. Enhancing surfactin production by using systematic CRISPRi repression to screen amino acid biosynthesis genes in Bacillus subtilis. Microb Cell Fact 2019; 18:90. [PMID: 31122258 PMCID: PMC6533722 DOI: 10.1186/s12934-019-1139-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/17/2019] [Indexed: 11/12/2022] Open
Abstract
Background Surfactin is a cyclic lipopeptide that is of great industrial use owing to its extraordinary surfactant power and antimicrobial, antiviral, and antitumor activities. Surfactin is synthesized by a condensation reaction in microbes, which uses fatty acids and four kinds of amino acids (l-glutamate, l-aspartate, l-leucine and l-valine) as precursors. Surfactin biosynthesis could be improved by increasing the supply of fatty acids; however, the effect of the regulation of amino acid metabolism on surfactin production was not yet clear. Results In this study, we aimed to improve surfactin production in B. subtilis by repressing the genes on the branch metabolic pathways of amino acid biosynthesis using CRISPRi technology. First, 20 genes were inhibited individually, resulting in 2.5- to 627-fold decreases in transcriptional level as determined by RT-qPCR. Among the 20 recombinant strains, 16 strains obtained higher surfactin titres than that produced by the parent BS168NU-Sd strain (the surfactin production of BS168NU-Sd with only dCas9 but no sgRNA expression was 0.17 g/L). In particular, the strains in which the yrpC, racE or murC genes were inhibited individually produced 0.54, 0.41, or 0.42 g/L surfactin, respectively. All three genes are related to the metabolism of l-glutamate, whose acylation is the first step in the surfactin condensation reaction. Furthermore, these three genes were repressed in combination, and the strain with co-inhibition of yrpC and racE produced 0.75 g/L surfactin, which was 4.69-fold higher than that of the parent strain. In addition, the inhibition of bkdAA and bkdAB, which are related to the metabolism of l-leucine and l-valine, not only improved surfactin production but also increased the proportion of the C14 isoform. Conclusions This study, to the best of our knowledge for the first time, systematically probed the regulatory effect of increasing the supply of amino acids on surfactin production. It provided an effective strategy and a new perspective for systematic studies on surfactin and other amino acid-derived chemicals. Electronic supplementary material The online version of this article (10.1186/s12934-019-1139-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Congya Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, People's Republic of China
| | - Yingxiu Cao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, People's Republic of China
| | - Yongping Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, People's Republic of China
| | - Liming Sun
- Petrochemical Research Institute, PetroChina Company Limited, Beijing, 102206, China
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, People's Republic of China.
| |
Collapse
|
9
|
Hu F, Liu Y, Li S. Rational strain improvement for surfactin production: enhancing the yield and generating novel structures. Microb Cell Fact 2019; 18:42. [PMID: 30819187 PMCID: PMC6394072 DOI: 10.1186/s12934-019-1089-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/18/2019] [Indexed: 01/10/2023] Open
Abstract
Surfactin, one of the most powerful microbial surfactants, is a lipopeptide-type biosurfactant which combines interesting physicochemical properties and biological activities. However, the high cost caused by its low productivity largely limits the commercial application of surfactin. Hence, many engineered bacterium have also been used to enhance surfactin biosynthesis. This review briefly summarizes the mechanism of surfactin biosynthesis, highlighting the synthesis pathway of N-terminally attached fatty acids, and outlines the main genetic engineering strategies for improving the yield and generating novel structures of surfactin, including promoter engineering, enhancing efflux systems, modifying the transcriptional regulatory genes of surfactin synthase (srfA), genomics and transcriptomics analysis, non ribosomal peptide synthetase (NRPS) domain and combinatorial biosynthesis. Finally, we discuss the future prospects of the research on surfactin.
Collapse
Affiliation(s)
- Fangxiang Hu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing, Jiangsu, China
| | - Yuyue Liu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing, Jiangsu, China
| | - Shuang Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 Puzhu South Road, Nanjing, Jiangsu, China.
| |
Collapse
|
10
|
Schäfer H, Heinz A, Sudzinová P, Voß M, Hantke I, Krásný L, Turgay K. Spx, the central regulator of the heat and oxidative stress response in B. subtilis, can repress transcription of translation-related genes. Mol Microbiol 2018; 111:514-533. [PMID: 30480837 DOI: 10.1111/mmi.14171] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2018] [Indexed: 12/19/2022]
Abstract
Spx is a Bacillus subtilis transcription factor that interacts with the alpha subunits of RNA polymerase. It can activate the thiol stress response regulon and interfere with the activation of many developmental processes. Here, we show that Spx is a central player orchestrating the heat shock response by up-regulating relevant stress response genes as revealed by comparative transcriptomic experiments. Moreover, these experiments revealed the potential of Spx to inhibit transcription of translation-related genes. By in vivo and in vitro experiments, we confirmed that Spx can inhibit transcription from rRNA. This inhibition depended mostly on UP elements and the alpha subunits of RNA polymerase. However, the concurrent up-regulation activity of stress genes by Spx, but not the inhibition of translation related genes, was essential for mediating stress response and antibiotic tolerance under the applied stress conditions. The observed inhibitory activity might be compensated in vivo by additional stress response processes interfering with translation. Nevertheless, the impact of Spx on limiting translation becomes apparent under conditions with high cellular Spx levels. Interestingly, we observed a subpopulation of stationary phase cells that contains raised Spx levels, which may contribute to growth inhibition and a persister-like behaviour of this subpopulation during outgrowth.
Collapse
Affiliation(s)
- Heinrich Schäfer
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Anja Heinz
- Institute of Biology-Microbiology, Freie Universität Berlin, Königin-Luise-Str. 12-16, D-14195, Berlin, Germany
| | - Petra Sudzinová
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague, Czech Republic
| | - Michelle Voß
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Ingo Hantke
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague, Czech Republic
| | - Kürşad Turgay
- Institute of Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
| |
Collapse
|
11
|
Wu Q, Zhi Y, Xu Y. Systematically engineering the biosynthesis of a green biosurfactant surfactin by Bacillus subtilis 168. Metab Eng 2018; 52:87-97. [PMID: 30453038 DOI: 10.1016/j.ymben.2018.11.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 11/24/2022]
Abstract
The biosynthesis of surfactin has attracted broad interest; however, there is a bottleneck in its low yield in wild strains and the ability to engineer Bacillus producers. Because the key metabolic mechanisms in the surfactin synthesis pathway remain unclear, genetic engineering approaches are all ending up with a single or a few gene modifications. The aim of this study is to develop a systematic engineering approach to improve the biosynthesis of surfactin. First, we restored surfactin biosynthetic activity by integrating a complete sfp gene into the nonproducing Bacillus subtilis 168 strain and obtained a surfactin titer of 0.4 g/l. Second, we reduced competition by deleting biofilm formation-related genes and nonribosomal peptide synthetases/polyketide synthase pathways (3.8% of the total genome), which increased the surfactin titer by 3.3-fold. Third, we improved cellular tolerance to surfactin by overexpressing potential self-resistance-associated proteins, which further increased the surfactin titer by 8.5-fold. Fourth, we increased the supply of precursor branched-chain fatty acids by engineering the branched-chain fatty acid biosynthesis pathway, resulting in an increase of the surfactin titer to 8.5 g/l (a 20.3-fold increase). Finally, due to the preference of the glycolytic pathway for cell growth, we diverted precursor acetyl-CoA away from cell growth to surfactin biosynthesis by enhancing the transcription of srfA. The final surfactin titer increased to 12.8 g/l, with a yield of 65.0 mmol/mol sucrose (42% of the theoretical yield) in the metabolically engineered strain. To the best of our knowledge, this is the highest titer and yield that has been reported. This study may pave the way for the commercial production of green surfactin. More broadly, our work presents another successful example of the modularization of metabolic pathways for improving titer and yield in biotechnological production.
Collapse
Affiliation(s)
- Qun Wu
- Key Laboratory of Industrial Biotechnology of Ministry of Education, State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China; Suqian Industrial Technology Research Institute of Jiangnan University, Suqian 223800, China
| | - Yan Zhi
- Key Laboratory of Industrial Biotechnology of Ministry of Education, State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yan Xu
- Key Laboratory of Industrial Biotechnology of Ministry of Education, State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
| |
Collapse
|
12
|
Exploring the Amino Acid Residue Requirements of the RNA Polymerase (RNAP) α Subunit C-Terminal Domain for Productive Interaction between Spx and RNAP of Bacillus subtilis. J Bacteriol 2017; 199:JB.00124-17. [PMID: 28484046 DOI: 10.1128/jb.00124-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/01/2017] [Indexed: 01/21/2023] Open
Abstract
Bacillus subtilis Spx is a global transcriptional regulator that is conserved among Gram-positive bacteria, in which Spx is required for preventing oxidatively induced proteotoxicity. Upon stress induction, Spx engages RNA polymerase (RNAP) through interaction with the C-terminal domain of the rpoA-encoded RNAP α subunit (αCTD). Previous mutational analysis of rpoA revealed that substitutions of Y263 in αCTD severely impaired Spx-activated transcription. Attempts to substitute alanine for αCTD R261, R268, R289, E255, E298, and K294 were unsuccessful, suggesting that these residues are essential. To determine whether these RpoA residues were required for productive Spx-RNAP interaction, we ectopically expressed the putatively lethal rpoA mutant alleles in the rpoAY263C mutant, where "Y263C" indicates the amino acid change that results from mutation of the allele. By complementation analysis, we show that Spx-bound αCTD amino acid residues are not essential for Spx-activated transcription in vivo but that R261A, E298A, and E255A mutants confer a partial defect in NaCl-stress induction of Spx-controlled genes. In addition, strains expressing rpoAE255A are defective in disulfide stress resistance and produce RNAP having a reduced affinity for Spx. The E255 residue corresponds to Escherichia coli αD259, which has been implicated in αCTD-σ70 interaction (σ70 R603, corresponding to R362 of B. subtilis σA). However, the combined rpoAE255A and sigAR362A mutations have an additive negative effect on Spx-dependent expression, suggesting the residues' differing roles in Spx-activated transcription. Our findings suggest that, while αCTD is essential for Spx-activated transcription, Spx is the primary DNA-binding determinant of the Spx-αCTD complex.IMPORTANCE Though extensively studied in Escherichia coli, the role of αCTD in activator-stimulated transcription is largely uncharacterized in Bacillus subtilis Here, we conduct phenotypic analyses of putatively lethal αCTD alanine codon substitution mutants to determine whether these residues function in specific DNA binding at the Spx-αCTD-DNA interface. Our findings suggest that multisubunit RNAP contact to Spx is optimal for activation while Spx fulfills the most stringent requirement of upstream promoter binding. Furthermore, several αCTD residues targeted for mutagenesis in this study are conserved among many bacterial species and thus insights on their function in other regulatory systems may be suggested herein.
Collapse
|
13
|
A Redox-Responsive Transcription Factor Is Critical for Pathogenesis and Aerobic Growth of Listeria monocytogenes. Infect Immun 2017; 85:IAI.00978-16. [PMID: 28193635 PMCID: PMC5400837 DOI: 10.1128/iai.00978-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/07/2017] [Indexed: 11/25/2022] Open
Abstract
Bacterial pathogens have evolved sophisticated mechanisms to sense and adapt to redox stress in nature and within the host. However, deciphering the redox environment encountered by intracellular pathogens in the mammalian cytosol is challenging, and that environment remains poorly understood. In this study, we assessed the contributions of the two redox-responsive, Spx-family transcriptional regulators to the virulence of Listeria monocytogenes, a Gram-positive facultative intracellular pathogen. Spx-family proteins are highly conserved in Firmicutes, and the L. monocytogenes genome contains two paralogues, spxA1 and spxA2. Here, we demonstrate that spxA1, but not spxA2, is required for the oxidative stress response and pathogenesis. SpxA1 function appeared to be conserved with the Bacillus subtilis homologue, and resistance to oxidative stress required the canonical CXXC redox-sensing motif. Remarkably, spxA1 was essential for aerobic growth, demonstrating that L. monocytogenes SpxA1 likely regulates a distinct set of genes. Although the ΔspxA1 mutant did not grow in the presence of oxygen in the laboratory, it was able to replicate in macrophages and colonize the spleens, but not the livers, of infected mice. These data suggest that the redox state of bacteria during infection differs significantly from that of bacteria growing in vitro. Further, the host cell cytosol may resemble an anaerobic environment, with tissue-specific variations in redox stress and oxygen concentration.
Collapse
|
14
|
Genome and transcriptome analysis of surfactin biosynthesis in Bacillus amyloliquefaciens MT45. Sci Rep 2017; 7:40976. [PMID: 28112210 PMCID: PMC5256033 DOI: 10.1038/srep40976] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/13/2016] [Indexed: 11/23/2022] Open
Abstract
Natural Bacillus isolates generate limited amounts of surfactin (<10% of their biomass), which functions as an antibiotic or signalling molecule in inter-/intra-specific interactions. However, overproduction of surfactin in Bacillus amyloliquefaciens MT45 was observed at a titre of 2.93 g/l, which is equivalent to half of the maximum biomass. To systemically unravel this efficient biosynthetic process, the genome and transcriptome of this bacterium were compared with those of B. amyloliquefaciens type strain DSM7T. MT45 possesses a smaller genome while containing more unique transporters and resistance-associated genes. Comparative transcriptome analysis revealed notable enrichment of the surfactin synthesis pathway in MT45, including central carbon metabolism and fatty acid biosynthesis to provide sufficient quantities of building precursors. Most importantly, the modular surfactin synthase overexpressed (9 to 49-fold) in MT45 compared to DSM7T suggested efficient surfactin assembly and resulted in the overproduction of surfactin. Furthermore, based on the expression trends observed in the transcriptome, there are multiple potential regulatory genes mediating the expression of surfactin synthase. Thus, the results of the present study provide new insights regarding the synthesis and regulation of surfactin in high-producing strain and enrich the genomic and transcriptomic resources available for B. amyloliquefaciens.
Collapse
|
15
|
Evidence that Oxidative Stress Induces spxA2 Transcription in Bacillus anthracis Sterne through a Mechanism Requiring SpxA1 and Positive Autoregulation. J Bacteriol 2016; 198:2902-2913. [PMID: 27501985 PMCID: PMC5055595 DOI: 10.1128/jb.00512-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/02/2016] [Indexed: 12/22/2022] Open
Abstract
Bacillus anthracis possesses two paralogs of the transcriptional regulator, Spx. SpxA1 and SpxA2 interact with RNA polymerase (RNAP) to activate the transcription of genes implicated in the prevention and alleviation of oxidative protein damage. The spxA2 gene is highly upregulated in infected macrophages, but how this is achieved is unknown. Previous studies have shown that the spxA2 gene was under negative control by the Rrf2 family repressor protein, SaiR, whose activity is sensitive to oxidative stress. These studies also suggested that spxA2 was under positive autoregulation. In the present study, we show by in vivo and in vitro analyses that spxA2 is under direct autoregulation but is also dependent on the SpxA1 paralogous protein. The deletion of either spxA1 or spxA2 reduced the diamide-inducible expression of an spxA2-lacZ construct. In vitro transcription reactions using purified B. anthracis RNAP showed that SpxA1 and SpxA2 protein stimulates transcription from a DNA fragment containing the spxA2 promoter. Ectopically positioned spxA2-lacZ fusion requires both SpxA1 and SpxA2 for expression, but the requirement for SpxA1 is partially overcome when saiR is deleted. Electrophoretic mobility shift assays showed that SpxA1 and SpxA2 enhance the affinity of RNAP for spxA2 promoter DNA and that this activity is sensitive to reductant. We hypothesize that the previously observed upregulation of spxA2 in the oxidative environment of the macrophage is at least partly due to SpxA1-mediated SaiR repressor inactivation and the positive autoregulation of spxA2 transcription. IMPORTANCE Regulators of transcription initiation are known to govern the expression of genes required for virulence in pathogenic bacterial species. Members of the Spx family of transcription factors function in control of genes required for virulence and viability in low-GC Gram-positive bacteria. In Bacillus anthracis, the spxA2 gene is highly induced in infected macrophages, which suggests an important role in the control of virulence gene expression during the anthrax disease state. We provide evidence that elevated concentrations of oxidized, active SpxA2 result from an autoregulatory positive-feedback loop driving spxA2 transcription.
Collapse
|
16
|
Molière N, Hoßmann J, Schäfer H, Turgay K. Role of Hsp100/Clp Protease Complexes in Controlling the Regulation of Motility in Bacillus subtilis. Front Microbiol 2016; 7:315. [PMID: 27014237 PMCID: PMC4793158 DOI: 10.3389/fmicb.2016.00315] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/29/2016] [Indexed: 11/16/2022] Open
Abstract
The Hsp100/Clp protease complexes of Bacillus subtilis ClpXP and ClpCP are involved in the control of many interconnected developmental and stress response regulatory networks, including competence, redox stress response, and motility. Here we analyzed the role of regulatory proteolysis by ClpXP and ClpCP in motility development. We have demonstrated that ClpXP acts on the regulation of motility by controlling the levels of the oxidative and heat stress regulator Spx. We obtained evidence that upon oxidative stress Spx not only induces the thiol stress response, but also transiently represses the transcription of flagellar genes. Furthermore, we observed that in addition to the known impact of ClpCP via the ComK/FlgM-dependent pathway, ClpCP also affects flagellar gene expression via modulating the activity and levels of the global regulator DegU-P. This adds another layer to the intricate involvement of Clp mediated regulatory proteolysis in different gene expression programs, which may allow to integrate and coordinate different signals for a better-adjusted response to the changing environment of B. subtilis cells.
Collapse
Affiliation(s)
- Noël Molière
- Naturwissenschaftliche Fakultät, Institut für Mikrobiologie, Leibniz Universität HannoverHannover, Germany; Institut für Biologie-Mikrobiologie, Freie Universität BerlinBerlin, Germany
| | - Jörn Hoßmann
- Institut für Biologie-Mikrobiologie, Freie Universität Berlin Berlin, Germany
| | - Heinrich Schäfer
- Naturwissenschaftliche Fakultät, Institut für Mikrobiologie, Leibniz Universität Hannover Hannover, Germany
| | - Kürşad Turgay
- Naturwissenschaftliche Fakultät, Institut für Mikrobiologie, Leibniz Universität HannoverHannover, Germany; Institut für Biologie-Mikrobiologie, Freie Universität BerlinBerlin, Germany
| |
Collapse
|
17
|
Murayama S, Ishikawa S, Chumsakul O, Ogasawara N, Oshima T. The Role of α-CTD in the Genome-Wide Transcriptional Regulation of the Bacillus subtilis Cells. PLoS One 2015; 10:e0131588. [PMID: 26154296 PMCID: PMC4495994 DOI: 10.1371/journal.pone.0131588] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 06/02/2015] [Indexed: 11/22/2022] Open
Abstract
The amino acid sequence of the RNA polymerase (RNAP) α-subunit is well conserved throughout the Eubacteria. Its C-terminal domain (α-CTD) is important for the transcriptional regulation of specific promoters in both Escherichia coli and Bacillus subtilis, through interactions with transcription factors and/or a DNA element called the "UP element". However, there is only limited information regarding the α-CTD regulated genes in B. subtilis and the importance of this subunit in the transcriptional regulation of B. subtilis. Here, we established strains and the growth conditions in which the α-subunit of RNAP was replaced with a C-terminally truncated version. Transcriptomic and ChAP-chip analyses revealed that α-CTD deficiency reduced the transcription and RNAP binding of genes related to the utilization of secondary carbon sources, transition state responses, and ribosome synthesis. In E. coli, it is known that α-CTD also contributes to the expression of genes related to the utilization of secondary carbon sources and ribosome synthesis. Our results suggest that the biological importance of α-CTD is conserved in B. subtilis and E. coli, but that its specific roles have diversified between these two bacteria.
Collapse
Affiliation(s)
- Satohiko Murayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Shu Ishikawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Onuma Chumsakul
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Naotake Ogasawara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| |
Collapse
|
18
|
Residue substitutions near the redox center of Bacillus subtilis Spx affect RNA polymerase interaction, redox control, and Spx-DNA contact at a conserved cis-acting element. J Bacteriol 2013; 195:3967-78. [PMID: 23813734 DOI: 10.1128/jb.00645-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Spx, a member of the ArsC protein family, is a regulatory factor that interacts with RNA polymerase (RNAP). It is highly conserved in Gram-positive bacteria and controls transcription on a genome-wide scale in response to oxidative stress. The structural requirements for RNAP interaction and promoter DNA recognition by Spx were examined through mutational analysis. Residues near the CxxC redox disulfide center of Spx functioned in RNAP α subunit interaction and in promoter DNA binding. R60E and C10A mutants were shown previously to confer defects in transcriptional activation, but both were able to interact with RNAP. R92, which is conserved in ArsC-family proteins, is likely involved in redox control of Spx, as the C10A mutation, which blocks disulfide formation, was epistatic to the R92A mutation. The R91A mutation reduced transcriptional activation and repression, suggesting a defect in RNAP interaction, which was confirmed by interaction assays using an epitope-tagged mutant protein. Protein-DNA cross-linking detected contact between RNAP-bound Spx and the AGCA element at −44 that is conserved in Spx-controlled genes. This interaction caused repositioning of the RNAP σA subunit from a −35-like element upstream of the trxB (thioredoxin reductase) promoter to positions −36 and −11 of the core promoter. The study shows that RNAP-bound Spx contacts a conserved upstream promoter sequence element when bound to RNAP.
Collapse
|
19
|
SOS response activation and competence development are antagonistic mechanisms in Streptococcus thermophilus. J Bacteriol 2012. [PMID: 23204467 DOI: 10.1128/jb.01605-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus includes species that either contain or lack the LexA-like repressor (HdiR) of the classical SOS response. In Streptococcus pneumoniae, a species which belongs to the latter group, SOS response inducers (e.g., mitomycin C [Mc] and fluoroquinolones) were shown to induce natural transformation, leading to the hypothesis that DNA damage-induced competence could contribute to genomic plasticity and stress resistance. Using reporter strains and microarray experiments, we investigated the impact of the SOS response inducers mitomycin C and norfloxacin and the role of HdiR on competence development in Streptococcus thermophilus. We show that both the addition of SOS response inducers and HdiR inactivation have a dual effect, i.e., induction of the expression of SOS genes and reduction of transformability. Reduction of transformability results from two different mechanisms, since HdiR inactivation has no major effect on the expression of competence (com) genes, while mitomycin C downregulates the expression of early and late com genes in a dose-dependent manner. The downregulation of com genes by mitomycin C was shown to take place at the level of the activation of the ComRS signaling system by an unknown mechanism. Conversely, we show that a ComX-deficient strain is more resistant to mitomycin C and norfloxacin in a viability plate assay, which indicates that competence development negatively affects the resistance of S. thermophilus to DNA-damaging agents. Altogether, our results strongly suggest that SOS response activation and competence development are antagonistic processes in S. thermophilus.
Collapse
|
20
|
Rochat T, Nicolas P, Delumeau O, Rabatinová A, Korelusová J, Leduc A, Bessières P, Dervyn E, Krásny L, Noirot P. Genome-wide identification of genes directly regulated by the pleiotropic transcription factor Spx in Bacillus subtilis. Nucleic Acids Res 2012; 40:9571-83. [PMID: 22904090 PMCID: PMC3479203 DOI: 10.1093/nar/gks755] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The transcriptional regulator Spx plays a key role in maintaining the redox homeostasis of Bacillus subtilis cells exposed to disulfide stress. Defects in Spx were previously shown to lead to differential expression of numerous genes but direct and indirect regulatory effects could not be distinguished. Here we identified 283 discrete chromosomal sites potentially bound by the Spx–RNA polymerase (Spx–RNAP) complex using chromatin immunoprecipitation of Spx. Three quarters of these sites were located near Sigma(A)-dependent promoters, and upon diamide treatment, the fraction of the Spx–RNAP complex increased in parallel with the number and occupancy of DNA sites. Correlation of Spx–RNAP-binding sites with gene differential expression in wild-type and Δspx strains exposed or not to diamide revealed that 144 transcription units comprising 275 genes were potentially under direct Spx regulation. Spx-controlled promoters exhibited an extended −35 box in which nucleotide composition at the −43/−44 positions strongly correlated with observed activation. In vitro transcription confirmed activation by oxidized Spx of seven newly identified promoters, of which one was also activated by reduced Spx. Our study globally characterized the Spx regulatory network, revealing its role in the basal expression of some genes and its complex interplay with other stress responses.
Collapse
|
21
|
Evidence that a single monomer of Spx can productively interact with RNA polymerase in Bacillus subtilis. J Bacteriol 2012; 194:1697-707. [PMID: 22307755 DOI: 10.1128/jb.06660-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spx activates transcription initiation in Bacillus subtilis by directly interacting with the C-terminal domain of the RNA polymerase (RNAP) holoenzyme α subunit, which generates a complex that recognizes the promoter regions of genes within the Spx regulon. Many Gram-positive species possess multiple paralogs of Spx, suggesting that two paralogous forms of Spx could simultaneously contact RNAP. The composition of Spx/RNAP was examined in vitro using an Spx variant (SpxΔCHA) bearing a 12-amino-acid deletion of the C terminus (SpxΔC) and a hemagglutinin (HA) epitope tag and Spxc-Myc, a full-length Spx with a C-terminal myelocytomatosis oncoprotein (c-Myc) epitope tag. All Spx/RNAP complexes bearing deletion or C-terminal-tagged variants were transcriptionally active in vivo and in vitro. Reaction mixtures containing SpxΔCHA and Spxc-Myc combined with RNAP were applied to either anti-HA or anti-c-Myc affinity columns. Eluted fractions contained RNAP with only one of the epitope-tagged Spx derivatives. The resin-bound RNAP complex bearing a single epitope-tagged Spx derivative was transcriptionally active. In vivo production of SpxΔC and SpxΔCHA followed by anti-HA affinity column chromatography of a cleared lysate resulted in retrieval of Spx/RNAP with only the SpxΔCHA derivative. Binding reactions that combined active Spxc-Myc, inactive Spx(R60E)ΔCHA, and RNAP, when applied to the anti-HA affinity column, yielded only inactive Spx(R60E)ΔCHA/RNAP complexes. The results strongly argue for a model in which a single Spx monomer engages RNAP to generate an active transcriptional complex.
Collapse
|
22
|
YjbH-enhanced proteolysis of Spx by ClpXP in Bacillus subtilis is inhibited by the small protein YirB (YuzO). J Bacteriol 2011; 193:2133-40. [PMID: 21378193 DOI: 10.1128/jb.01350-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Spx protein of Bacillus subtilis is a global regulator of the oxidative stress response. Spx concentration is controlled at the level of proteolysis by the ATP-dependent protease ClpXP and a substrate-binding protein, YjbH, which interacts with Spx. A yeast two-hybrid screen was carried out using yjbH as bait to uncover additional substrates or regulators of YjbH activity. Of the several genes identified in the screen, one encoded a small protein, YirB (YuzO), which elevated Spx concentration and activity in vivo when overproduced from an isopropyl-β-D-thiogalactopyranoside (IPTG)-inducible yirB construct. Pulldown experiments using extracts of B. subtilis cells producing a His-tagged YirB showed that native YjbH interacts with YirB in B. subtilis. Pulldown experiments using affinity-tagged Spx showed that YirB inhibited YjbH interaction with Spx. In vitro, YjbH-mediated proteolysis of Spx by ClpXP was inhibited by YirB. The activity of YirB is similar to that of the antiadaptor proteins that were previously shown to reduce proteolysis of a specific ClpXP substrate by interacting with a substrate-binding protein.
Collapse
|
23
|
Nakano MM, Lin A, Zuber CS, Newberry KJ, Brennan RG, Zuber P. Promoter recognition by a complex of Spx and the C-terminal domain of the RNA polymerase alpha subunit. PLoS One 2010; 5:e8664. [PMID: 20084284 PMCID: PMC2801614 DOI: 10.1371/journal.pone.0008664] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 12/19/2009] [Indexed: 12/20/2022] Open
Abstract
Background Spx, an ArsC (arsenate reductase) family member, is a global transcriptional regulator of the microbial stress response and is highly conserved amongst Gram-positive bacteria. Bacillus subtilis Spx protein exerts positive and negative control of transcription through its interaction with the C-terminal domain of the RNA polymerase (RNAP) α subunit (αCTD). Spx activates trxA (thioredoxin) and trxB (thioredoxin reductase) in response to thiol stress, and bears an N-terminal C10XXC13 redox disulfide center that is oxidized in active Spx. Methodology/Principal Findings The structure of mutant SpxC10S showed a change in the conformation of helix α4. Amino acid substitutions R60E and K62E within and adjacent to helix α4 conferred defects in Spx-activated transcription but not Spx-dependent repression. Electrophoretic mobility-shift assays showed αCTD interaction with trxB promoter DNA, but addition of Spx generated a supershifted complex that was disrupted in the presence of reductant (DTT). Interaction of αCTD/Spx complex with promoter DNA required the cis-acting elements -45AGCA-42 and -34AGCG-31 of the trxB promoter. The SpxG52R mutant, defective in αCTD binding, did not interact with the αCTD-trxB complex. SpxR60E not only failed to complex with αCTD-trxB, but also disrupted αCTD-trxB DNA interaction. Conclusions/Significance The results show that Spx and αCTD form a complex that recognizes the promoter DNA of an Spx-controlled gene. A conformational change during oxidation of Spx to the disulfide form likely alters the structure of Spx α helix α4, which contains residues that function in transcriptional activation and αCTD/Spx-promoter interaction. The results suggest that one of these residues, R60 of the α4 region of oxidized Spx, functions in αCTD/Spx-promoter contact but not in αCTD interaction.
Collapse
Affiliation(s)
- Michiko M. Nakano
- Department of Science & Engineering, School of Medicine, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Ann Lin
- Department of Science & Engineering, School of Medicine, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Cole S. Zuber
- Department of Science & Engineering, School of Medicine, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Kate J. Newberry
- Department of Biochemistry and Molecular Biology, University of Texas, M. D. Anderson Cancer Center, Texas, United States of America
| | - Richard G. Brennan
- Department of Biochemistry and Molecular Biology, University of Texas, M. D. Anderson Cancer Center, Texas, United States of America
| | - Peter Zuber
- Department of Science & Engineering, School of Medicine, Oregon Health & Science University, Beaverton, Oregon, United States of America
- * E-mail:
| |
Collapse
|
24
|
Licht A, Brantl S. The transcriptional repressor CcpN from Bacillus subtilis uses different repression mechanisms at different promoters. J Biol Chem 2009; 284:30032-8. [PMID: 19726675 DOI: 10.1074/jbc.m109.033076] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CcpN, a transcriptional repressor from Bacillus subtilis that is responsible for the carbon catabolite repression of three genes, has been characterized in detail in the past 4 years. However, nothing is known about the actual repression mechanism as yet. Here, we present a detailed study on how CcpN exerts its repression effect at its three known target promoters of the genes sr1, pckA, and gapB. Using gel shift assays under non-repressive and repressive conditions, we showed that CcpN and RNA polymerase can bind simultaneously and that CcpN does not prevent RNA polymerase (RNAP) binding to the promoter. Furthermore, we investigated the effect of CcpN on open complex formation and demonstrate that CcpN also does not act at this step of transcription initiation at the sr1 and pckA and presumably at the gapB promoter. Investigation of abortive transcript synthesis revealed that CcpN acts differently at the three promoters: At the sr1 and pckA promoter, promoter clearance is impeded by CcpN, whereas synthesis of abortive transcripts is repressed at the gapB promoter. Eventually, we demonstrated with Far Western blots and co-elution experiments that CcpN is able to interact with the RNAP alpha-subunit, which completes the picture of the requirements for the repressive action of CcpN. On the basis of the presented results, we propose a new working model for CcpN action.
Collapse
Affiliation(s)
- Andreas Licht
- Arbeitsgruppe Bakteriengenetik, Friedrich-Schiller-Universität, 07743 Jena, Germany.
| | | |
Collapse
|
25
|
Turlan C, Prudhomme M, Fichant G, Martin B, Gutierrez C. SpxA1, a novel transcriptional regulator involved in X-state (competence) development in Streptococcus pneumoniae. Mol Microbiol 2009; 73:492-506. [PMID: 19627499 DOI: 10.1111/j.1365-2958.2009.06789.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Streptococcus pneumoniae is a naturally transformable human pathogen. Genome and phylogenetic analyses uncovered two Spx-like global transcriptional regulators, SpxA1 and SpxA2, encoded by S. pneumoniae. spxA1 and spxA2 are not essential, but their simultaneous inactivation is lethal. SpxA1 represses transcription of the early competence operon comCDE and thereby negatively regulates the initiation of the X-state (competence). The molecular basis of this repression could be similar to that of SpxA of Bacillus subtilis, involving a specific interaction with the alpha subunit of RNA polymerase. S. pneumoniae lacks an SOS-like stress response and the X-state is proposed to be a general stress response mechanism in this species. In light of this, SpxA1-dependent repression could act to sense environmental or metabolic stresses and prevent launching of the X-state in the absence of stress.
Collapse
Affiliation(s)
- Catherine Turlan
- Université de Toulouse, UPS, Laboratoire de Microbiologie et Génétique Moléculaire, F31000 Toulouse, France
| | | | | | | | | |
Collapse
|
26
|
Activation of the promoter of the fengycin synthetase operon by the UP element. J Bacteriol 2009; 191:4615-23. [PMID: 19447911 DOI: 10.1128/jb.00255-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis F29-3 produces an antifungal peptidic antibiotic that is synthesized nonribosomally by fengycin synthetases. Our previous work established that the promoter of the fengycin synthetase operon is located 86 nucleotides upstream of the translational initiation codon of fenC. This investigation involved transcriptional fusions with a DNA fragment that contains the region between positions -105 and +80 and determined that deleting the region between positions -55 and -42 reduces the promoter activity by 64.5%. Transcriptional fusions in the B. subtilis DB2 chromosome also indicated that mutating the sequence markedly reduces the promoter activity. An in vitro transcription analysis confirmed that the transcription is inefficient when the sequence in this region is mutated. Electrophoretic mobility shift and footprinting analyses demonstrated that the C-terminal domain of the RNA polymerase alpha subunit binds to the region between positions -55 and -39. These results indicated that the sequence is an UP element. Finally, this UP element is critical for the production of fengycin, since mutating the UP sequence in the chromosome of B. subtilis F29-3 reduces the transcription of the fen operon by 85% and prevents the cells from producing enough fengycin to suppress the germination of Paecilomyces variotii spores on agar plates.
Collapse
|
27
|
The YjbH protein of Bacillus subtilis enhances ClpXP-catalyzed proteolysis of Spx. J Bacteriol 2008; 191:1268-77. [PMID: 19074380 DOI: 10.1128/jb.01289-08] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The global transcriptional regulator Spx of Bacillus subtilis is controlled at several levels of the gene expression process. It is maintained at low concentrations during unperturbed growth by the ATP-dependent protease ClpXP. Under disulfide stress, Spx concentration increases due in part to a reduction in ClpXP-catalyzed proteolysis. Recent studies of Larsson and coworkers (Mol. Microbiol. 66:669-684, 2007) implicated the product of the yjbH gene as being necessary for the proteolytic control of Spx. In the present study, yeast two-hybrid analysis and protein-protein cross-linking showed that Spx interacts with YjbH. YjbH protein was shown to enhance the proteolysis of Spx in reaction mixtures containing ClpXP protease but not ClpCP protease. An N-terminal truncated form of YjbH with a deletion of residues 1 to 24 (YjbH(Delta1-24)) showed no proteolysis enhancement activity. YjbH is specific for Spx as it did not accelerate proteolysis of the ClpXP substrate green fluorescent protein (GFP)-SsrA, a GFP derivative with a C-terminal SsrA tag that is recognized by ClpXP. Using inductively coupled plasma atomic emission spectroscopy and 4-(2-pyridylazo) resorcinol release experiments, YjbH was found to contain zinc atoms. Zinc analysis of YjbH(Delta1-24) revealed that the N-terminal histidine-rich region is indispensable for the coordination of at least one Zn atom. A Zn atom coordinated by the N-terminal region was rapidly released from the protein upon treatment with a strong oxidant. In conclusion, YjbH is proposed to be an adaptor for ClpXP-catalyzed Spx degradation, and a model of YjbH redox control involving Zn dissociation is presented.
Collapse
|
28
|
Reyes DY, Zuber P. Activation of transcription initiation by Spx: formation of transcription complex and identification of a Cis-acting element required for transcriptional activation. Mol Microbiol 2008; 69:765-79. [PMID: 18687074 DOI: 10.1111/j.1365-2958.2008.06330.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The Spx protein of Bacillus subtilis interacts with RNA polymerase (RNAP) to activate transcription initiation in response to thiol-oxidative stress. Protein-DNA cross-linking analysis of reactions containing RNAP, Spx and trxA (thioredoxin) or trxB (thioredoxin reductase) promoter DNA was undertaken to uncover the organization of the Spx-activated transcription initiation complex. Spx induced contact between the RNAP sigma(A) subunit and the -10 promoter sequence of trxA and B, and contact of the betabeta' subunits with core promoter DNA. No Spx-DNA contact was detected. Spx mutants, Spx(C10A) and Spx(G52R.), or RNAP alpha C-terminal domain mutants that impair productive Spx-RNAP interaction did not induce heightened sigma and betabeta' contact with the core promoter. Deletion analysis and the activity of hybrid promoter constructs having upstream trxB DNA fused at positions -31, -36 and -41 of the srf (surfactin synthetase) promoter indicated that a cis-acting site between -50 and -36 was required for Spx activity. Mutations at -43 and -44 of trxB abolished Spx-dependent transcription and Spx-induced cross-linking between the sigma subunit and the -10 region. These data are consistent with a model that Spx activation requires contact between the Spx/RNAP complex and upstream promoter DNA, which allows Spx-induced engagement of the sigma and large subunits with the core promoter.
Collapse
Affiliation(s)
- Dindo Y Reyes
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, 20000 NW Walker Rd., Beaverton, OR 97006, USA.
| | | |
Collapse
|
29
|
Reder A, Höper D, Weinberg C, Gerth U, Fraunholz M, Hecker M. The Spx paralogue MgsR (YqgZ) controls a subregulon within the general stress response ofBacillus subtilis. Mol Microbiol 2008; 69:1104-20. [DOI: 10.1111/j.1365-2958.2008.06332.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
30
|
Griffith KL, Grossman AD. A degenerate tripartite DNA-binding site required for activation of ComA-dependent quorum response gene expression in Bacillus subtilis. J Mol Biol 2008; 381:261-75. [PMID: 18585392 DOI: 10.1016/j.jmb.2008.06.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 06/09/2008] [Accepted: 06/11/2008] [Indexed: 11/20/2022]
Abstract
In Bacillus subtilis, the transcription factor ComA activates several biological processes in response to increasing population density. Extracellular peptide signaling is used to coordinate the activity of ComA with population density. At low culture densities, when the concentration of signaling peptides is lowest, ComA is largely inactive. At higher densities, when the concentration of signaling peptides is higher, ComA is active and activates the transcription of at least nine operons involved in the development of competence and in the production of degradative enzymes and antibiotics. We found that ComA binds a degenerate tripartite sequence consisting of three DNA-binding determinants or "recognition elements." Mutational analyses showed that all three recognition elements are required for transcription activation in vivo and for specific DNA binding by ComA in vitro. Degeneracy of the recognition elements in the ComA-binding site is an important regulatory feature for coordinating transcription with population density (i.e., promoters containing an optimized binding site have high activity at low culture density and are no longer regulated in the normal-density-dependent manner). We found that purified ComA forms a dimer in solution, and we propose a model for how two dimers of ComA bind to an odd number of DNA-binding determinants to activate transcription of target genes. This DNA-protein architecture for transcription activation appears to be conserved for ComA homologs in other Bacillus species.
Collapse
Affiliation(s)
- Kevin L Griffith
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | |
Collapse
|
31
|
Geng H, Zuber P, Nakano MM. Regulation of respiratory genes by ResD-ResE signal transduction system in Bacillus subtilis. Methods Enzymol 2008; 422:448-64. [PMID: 17628154 DOI: 10.1016/s0076-6879(06)22023-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Successful respiration in Bacillus subtilis using oxygen or nitrate as the terminal electron acceptor requires the ResD-ResE signal transduction system. Although transcription of ResDE-controlled genes is induced at the stationary phase of aerobic growth, it is induced to a higher extent upon oxygen limitation. Furthermore, maximal transcriptional activation requires not only oxygen limitation, but also nitric oxide (NO). Oxygen limitation likely results in conversion of the ResE sensor kinase activity from a phosphatase-dominant to a kinase-dominant mode. In addition, low oxygen levels promote the production and maintenance of NO during nitrate respiration, which leads to elimination of the repression exerted by the NO-sensitive transcriptional regulator NsrR. ResD, after undergoing ResE-mediated phosphorylation, interacts with the C-terminal domain of the alpha subunit of RNA polymerase to activate transcription initiation at ResDE-controlled promoters.
Collapse
Affiliation(s)
- Hao Geng
- Department of Environmental System, Oregon Health and Science University, Beaverton, Oregon, USA
| | | | | |
Collapse
|
32
|
Zhang Y, Zuber P. Requirement of the zinc-binding domain of ClpX for Spx proteolysis in Bacillus subtilis and effects of disulfide stress on ClpXP activity. J Bacteriol 2007; 189:7669-80. [PMID: 17827297 PMCID: PMC2168722 DOI: 10.1128/jb.00745-07] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spx, a transcriptional regulator of the disulfide stress response in Bacillus subtilis, is under the proteolytic control of the ATP-dependent protease ClpXP. Previous studies suggested that ClpXP activity is down-regulated in response to disulfide stress, resulting in elevated concentrations of Spx. The effect of disulfide stress on ClpXP activity was examined using the thiol-specific oxidant diamide. ClpXP-catalyzed degradation of either Spx or a green fluorescent protein derivative bearing an SsrA tag recognized by ClpXP was inhibited by diamide treatment in vitro. Spx is also a substrate for MecA/ClpCP-catalyzed proteolysis in vitro, but diamide used at the concentrations that inhibited ClpXP had little observable effect on MecA/ClpCP activity. ClpX bears a Cys4 Zn-binding domain (ZBD), which in other Zn-binding proteins is vulnerable to thiol-reactive electrophiles. Diamide treatment caused partial release of Zn from ClpX and the formation of high-molecular-weight species, as observed by electrophoresis through nonreducing gels. Reduced Spx proteolysis in vitro and elevated Spx concentration in vivo resulted when two of the Zn-coordinating Cys residues of the ClpX ZBD were changed to Ser. This was reflected in enhanced Spx activity in both transcription activation and repression in cells expressing the Cys-to-Ser mutants. ClpXP activity in vivo is reduced when cells are exposed to diamide, as shown by the enhanced stability of an SsrA-tagged protein after treatment with the oxidant. The results are consistent with the hypothesis that inhibition of ClpXP by disulfide stress is due to structural changes to the N-terminal ZBD of ClpX.
Collapse
Affiliation(s)
- Ying Zhang
- Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, 20000 NW Walker Rd., Beaverton, OR 97006, USA
| | | |
Collapse
|
33
|
Geng H, Zhu Y, Mullen K, Zuber CS, Nakano MM. Characterization of ResDE-dependent fnr transcription in Bacillus subtilis. J Bacteriol 2006; 189:1745-55. [PMID: 17189364 PMCID: PMC1855754 DOI: 10.1128/jb.01502-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ResD-ResE signal transduction system is required for transcription of genes involved in aerobic and anaerobic respiration in Bacillus subtilis. Phosphorylated ResD (ResD approximately P) interacts with target DNA to activate transcription. A strong sequence similarity was detected in promoter regions of some ResD-controlled genes including fnr and resA. Single-base substitutions in the fnr and resA promoters were performed to determine a ResD-binding sequence. DNase I footprinting analysis indicated that ResD approximately P itself does not bind to fnr, but interaction of ResD approximately P with the C-terminal domain of the alpha subunit (alphaCTD) of RNA polymerase (RNAP) facilitates cooperative binding of ResD approximately P and RNAP, thereby increasing fnr transcription initiation. Consistent with this result, amino acid substitutions in alphaCTD, such as Y263A, K267A, A269I, or N290A, sharply reduced fnr transcription in vivo, and the K267A alphaCTD protein, unlike the wild-type protein, did not increase ResD approximately P binding to the fnr promoter. Amino acid residues of alphaCTD required for ResD-dependent fnr transcription, with the exception of N290, which may interact with DNA, constitute a distinct surface, suggesting that these residues likely interact with ResD approximately P.
Collapse
Affiliation(s)
- Hao Geng
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97006, USA
| | | | | | | | | |
Collapse
|
34
|
Leelakriangsak M, Kobayashi K, Zuber P. Dual negative control of spx transcription initiation from the P3 promoter by repressors PerR and YodB in Bacillus subtilis. J Bacteriol 2006; 189:1736-44. [PMID: 17158660 PMCID: PMC1855716 DOI: 10.1128/jb.01520-06] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The spx gene encodes an RNA polymerase-binding protein that exerts negative and positive transcriptional control in response to oxidative stress in Bacillus subtilis. It resides in the yjbC-spx operon and is transcribed from at least five promoters located in the yjbC regulatory region or in the yjbC-spx intergenic region. Induction of spx transcription in response to treatment with the thiol-specific oxidant diamide is the result of transcription initiation at the P(3) promoter located upstream of the spx coding sequence. Previous studies conducted elsewhere and analyses of transcription factor mutants using transformation array technology have uncovered two transcriptional repressors, PerR and YodB, that target the cis-acting negative control elements of the P(3) promoter. Expression of an spx-bgaB fusion carrying the P(3) promoter is elevated in a yodB or perR mutant, and an additive increase in expression was observed in a yodB perR double mutant. Primer extension analysis of spx RNA shows the same additive increase in P(3) transcript levels in yodB perR mutant cells. Purified YodB and PerR repress spx transcription in vitro when wild-type spx P(3) promoter DNA was used as a template. Point mutations at positions within the P(3) promoter relieved YodB-dependent repression, while a point mutation at position +24 reduced PerR repression. DNase I footprinting analysis showed that YodB protects a region that includes the P(3) -10 and -35 regions, while PerR binds to a region downstream of the P(3) transcriptional start site. The binding of both repressors is impaired by the treatment of footprinting reactions with diamide or hydrogen peroxide. The study has uncovered a mechanism of dual negative control that relates to the oxidative stress response of gram-positive bacteria.
Collapse
Affiliation(s)
- Montira Leelakriangsak
- OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97229, USA
| | | | | |
Collapse
|