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Pospíšil J, Schwarz M, Ziková A, Vítovská D, Hradilová M, Kolář M, Křenková A, Hubálek M, Krásný L, Vohradský J. σ E of Streptomyces coelicolor can function both as a direct activator or repressor of transcription. Commun Biol 2024; 7:46. [PMID: 38184746 PMCID: PMC10771440 DOI: 10.1038/s42003-023-05716-y] [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: 06/12/2023] [Accepted: 12/18/2023] [Indexed: 01/08/2024] Open
Abstract
σ factors are considered as positive regulators of gene expression. Here we reveal the opposite, inhibitory role of these proteins. We used a combination of molecular biology methods and computational modeling to analyze the regulatory activity of the extracytoplasmic σE factor from Streptomyces coelicolor. The direct activator/repressor function of σE was then explored by experimental analysis of selected promoter regions in vivo. Additionally, the σE interactome was defined. Taken together, the results characterize σE, its regulation, regulon, and suggest its direct inhibitory function (as a repressor) in gene expression, a phenomenon that may be common also to other σ factors and organisms.
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Affiliation(s)
- Jiří Pospíšil
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic.
| | - Marek Schwarz
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Alice Ziková
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Dragana Vítovská
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Miluše Hradilová
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Michal Kolář
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Alena Křenková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 542/2, 160 00, Prague 6, Czech Republic
| | - Martin Hubálek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 542/2, 160 00, Prague 6, Czech Republic
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Jiří Vohradský
- Laboratory of Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 142 20, Prague 4, Czech Republic.
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Hamed MB, Busche T, Simoens K, Carpentier S, Kormanec J, Van Mellaert L, Anné J, Kalinowski J, Bernaerts K, Karamanou S, Economou A. Enhanced protein secretion in reduced genome strains of Streptomyces lividans. Microb Cell Fact 2024; 23:13. [PMID: 38183102 PMCID: PMC10768272 DOI: 10.1186/s12934-023-02269-x] [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: 07/26/2023] [Accepted: 12/10/2023] [Indexed: 01/07/2024] Open
Abstract
BACKGROUND S. lividans TK24 is a popular host for the production of small molecules and the secretion of heterologous protein. Within its large genome, twenty-nine non-essential clusters direct the biosynthesis of secondary metabolites. We had previously constructed ten chassis strains, carrying deletions in various combinations of specialized metabolites biosynthetic clusters, such as those of the blue actinorhodin (act), the calcium-dependent antibiotic (cda), the undecylprodigiosin (red), the coelimycin A (cpk) and the melanin (mel) clusters, as well as the genes hrdD, encoding a non-essential sigma factor, and matAB, a locus affecting mycelial aggregation. Genome reduction was aimed at reducing carbon flow toward specialized metabolite biosynthesis to optimize the production of secreted heterologous protein. RESULTS Two of these S. lividans TK24 derived chassis strains showed ~ 15% reduction in biomass yield, 2-fold increase of their total native secretome mass yield and enhanced abundance of several secreted proteins compared to the parental strain. RNAseq and proteomic analysis of the secretome suggested that genome reduction led to cell wall and oxidative stresses and was accompanied by the up-regulation of secretory chaperones and of secDF, a Sec-pathway component. Interestingly, the amount of the secreted heterologous proteins mRFP and mTNFα, by one of these strains, was 12 and 70% higher, respectively, than that secreted by the parental strain. CONCLUSION The current study described a strategy to construct chassis strains with enhanced secretory abilities and proposed a model linking the deletion of specialized metabolite biosynthetic clusters to improved production of secreted heterologous proteins.
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Affiliation(s)
- Mohamed Belal Hamed
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Molecular Bacteriology, KU Leuven, Herestraat 49, Leuven, B-3000, Belgium
- Molecular Biology Depart, National Research Centre, Dokii, Cairo, Egypt
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
| | - Tobias Busche
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Kenneth Simoens
- Department of Chemical Engineering, Chemical and Biochemical Reactor Engineering and Safety (CREaS), KU Leuven, Leuven, B-3001, Belgium
| | - Sebastien Carpentier
- SYBIOMA, KU Leuven facility for Systems Biology Based Mass Spectrometry, Leuven, B-3000, Belgium
| | - Jan Kormanec
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, Bratislava, 84551, Slovakia
| | - Lieve Van Mellaert
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Molecular Bacteriology, KU Leuven, Herestraat 49, Leuven, B-3000, Belgium
| | - Jozef Anné
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Molecular Bacteriology, KU Leuven, Herestraat 49, Leuven, B-3000, Belgium
| | - Joern Kalinowski
- Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Kristel Bernaerts
- Department of Chemical Engineering, Chemical and Biochemical Reactor Engineering and Safety (CREaS), KU Leuven, Leuven, B-3001, Belgium
| | - Spyridoula Karamanou
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Molecular Bacteriology, KU Leuven, Herestraat 49, Leuven, B-3000, Belgium.
| | - Anastassios Economou
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Molecular Bacteriology, KU Leuven, Herestraat 49, Leuven, B-3000, Belgium
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Alshehri WA, Abulfaraj AA, Alqahtani MD, Alomran MM, Alotaibi NM, Alwutayd K, Aloufi AS, Alshehrei FM, Alabbosh KF, Alshareef SA, Ashy RA, Refai MY, Jalal RS. Abundant resistome determinants in rhizosphere soil of the wild plant Abutilon fruticosum. AMB Express 2023; 13:92. [PMID: 37646836 PMCID: PMC10469157 DOI: 10.1186/s13568-023-01597-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/18/2023] [Indexed: 09/01/2023] Open
Abstract
A metagenomic whole genome shotgun sequencing approach was used for rhizospheric soil micribiome of the wild plant Abutilon fruticosum in order to detect antibiotic resistance genes (ARGs) along with their antibiotic resistance mechanisms and to detect potential risk of these ARGs to human health upon transfer to clinical isolates. The study emphasized the potential risk to human health of such human pathogenic or commensal bacteria, being transferred via food chain or horizontally transferred to human clinical isolates. The top highly abundant rhizospheric soil non-redundant ARGs that are prevalent in bacterial human pathogens or colonizers (commensal) included mtrA, soxR, vanRO, golS, rbpA, kdpE, rpoB2, arr-1, efrA and ileS genes. Human pathogenic/colonizer bacteria existing in this soil rhizosphere included members of genera Mycobacterium, Vibrio, Klebsiella, Stenotrophomonas, Pseudomonas, Nocardia, Salmonella, Escherichia, Citrobacter, Serratia, Shigella, Cronobacter and Bifidobacterium. These bacteria belong to phyla Actinobacteria and Proteobacteria. The most highly abundant resistance mechanisms included antibiotic efflux pump, antibiotic target alteration, antibiotic target protection and antibiotic inactivation. antimicrobial resistance (AMR) families of the resistance mechanism of antibiotic efflux pump included resistance-nodulation-cell division (RND) antibiotic efflux pump (for mtrA, soxR and golS genes), major facilitator superfamily (MFS) antibiotic efflux pump (for soxR gene), the two-component regulatory kdpDE system (for kdpE gene) and ATP-binding cassette (ABC) antibiotic efflux pump (for efrA gene). AMR families of the resistance mechanism of antibiotic target alteration included glycopeptide resistance gene cluster (for vanRO gene), rifamycin-resistant beta-subunit of RNA polymerase (for rpoB2 gene) and antibiotic-resistant isoleucyl-tRNA synthetase (for ileS gene). AMR families of the resistance mechanism of antibiotic target protection included bacterial RNA polymerase-binding protein (for RbpA gene), while those of the resistance mechanism of antibiotic inactivation included rifampin ADP-ribosyltransferase (for arr-1 gene). Better agricultural and food transport practices are required especially for edible plant parts or those used in folkloric medicine.
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Affiliation(s)
- Wafa A Alshehri
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Aala A Abulfaraj
- Biological Sciences Department, College of Science & Arts, King Abdulaziz University, 21911, Rabigh, Saudi Arabia
| | - Mashael D Alqahtani
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Maryam M Alomran
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Nahaa M Alotaibi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Khairiah Alwutayd
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Abeer S Aloufi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O.Box 84428, 11671, Riyadh, Saudi Arabia
| | - Fatimah M Alshehrei
- Department of Biology, Jumum College University, Umm Al-Qura University, P.O. Box 7388, 21955, Makkah, Saudi Arabia
| | - Khulood F Alabbosh
- Department of Biology, College of Science, University of Hail, Hail, Saudi Arabia
| | - Sahar A Alshareef
- Department of Biology, College of Science and Arts at Khulis, University of Jeddah, 21921, Jeddah, Saudi Arabia
| | - Ruba A Ashy
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Mohammed Y Refai
- Department of Biochemistry, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia
| | - Rewaa S Jalal
- Department of Biology, College of Science, University of Jeddah, 21493, Jeddah, Saudi Arabia.
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Clara L, David C, Laila S, Virginie R, Marie-Joelle V. Comparative Proteomic Analysis of Transcriptional and Regulatory Proteins Abundances in S. lividans and S. coelicolor Suggests a Link between Various Stresses and Antibiotic Production. Int J Mol Sci 2022; 23:ijms232314792. [PMID: 36499130 PMCID: PMC9739823 DOI: 10.3390/ijms232314792] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/14/2022] [Accepted: 11/15/2022] [Indexed: 11/29/2022] Open
Abstract
Streptomyces coelicolor and Streptomyces lividans constitute model strains to study the regulation of antibiotics biosynthesis in Streptomyces species since these closely related strains possess the same pathways directing the biosynthesis of various antibiotics but only S. coelicolor produces them. To get a better understanding of the origin of the contrasted abilities of these strains to produce bioactive specialized metabolites, these strains were grown in conditions of phosphate limitation or proficiency and a comparative analysis of their transcriptional/regulatory proteins was carried out. The abundance of the vast majority of the 355 proteins detected greatly differed between these two strains and responded differently to phosphate availability. This study confirmed, consistently with previous studies, that S. coelicolor suffers from nitrogen stress. This stress likely triggers the degradation of the nitrogen-rich peptidoglycan cell wall in order to recycle nitrogen present in its constituents, resulting in cell wall stress. When an altered cell wall is unable to fulfill its osmo-protective function, the bacteria also suffer from osmotic stress. This study thus revealed that these three stresses are intimately linked in S. coelicolor. The aggravation of these stresses leading to an increase of antibiotic biosynthesis, the connection between these stresses, and antibiotic production are discussed.
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Affiliation(s)
- Lejeune Clara
- Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group “Energetic Metabolism of Streptomyces”, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Cornu David
- Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group “Energetic Metabolism of Streptomyces”, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Sago Laila
- Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group “Energetic Metabolism of Streptomyces”, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Redeker Virginie
- Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group “Energetic Metabolism of Streptomyces”, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
- Laboratory of Neurodegenerative Diseases, Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) and Centre National de la Recherche Scientifique (CNRS), Molecular Imaging Center (MIRCen), Institut François Jacob, Université Paris-Saclay, 92260 Fontenay-aux-Roses, France
| | - Virolle Marie-Joelle
- Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group “Energetic Metabolism of Streptomyces”, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
- Correspondence:
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5
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Shami AY, Abulfaraj AA, Refai MY, Barqawi AA, Binothman N, Tashkandi MA, Baeissa HM, Baz L, Abuauf HW, Ashy RA, Jalal RS. Abundant antibiotic resistance genes in rhizobiome of the human edible Moringa oleifera medicinal plant. Front Microbiol 2022; 13:990169. [PMID: 36187977 PMCID: PMC9524394 DOI: 10.3389/fmicb.2022.990169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022] Open
Abstract
Moringa oleifera (or the miracle tree) is a wild plant species widely grown for its seed pods and leaves, and is used in traditional herbal medicine. The metagenomic whole genome shotgun sequencing (mWGS) approach was used to characterize antibiotic resistance genes (ARGs) of the rhizobiomes of this wild plant and surrounding bulk soil microbiomes and to figure out the chance and consequences for highly abundant ARGs, e.g., mtrA, golS, soxR, oleC, novA, kdpE, vanRO, parY, and rbpA, to horizontally transfer to human gut pathogens via mobile genetic elements (MGEs). The results indicated that abundance of these ARGs, except for golS, was higher in rhizosphere of M. oleifera than that in bulk soil microbiome with no signs of emerging new soil ARGs in either soil type. The most highly abundant metabolic processes of the most abundant ARGs were previously detected in members of phyla Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Firmicutes. These processes refer to three resistance mechanisms namely antibiotic efflux pump, antibiotic target alteration and antibiotic target protection. Antibiotic efflux mechanism included resistance-nodulation-cell division (RND), ATP-binding cassette (ABC), and major facilitator superfamily (MFS) antibiotics pumps as well as the two-component regulatory kdpDE system. Antibiotic target alteration included glycopeptide resistance gene cluster (vanRO), aminocoumarin resistance parY, and aminocoumarin self-resistance parY. While, antibiotic target protection mechanism included RbpA bacterial RNA polymerase (rpoB)-binding protein. The study supports the claim of the possible horizontal transfer of these ARGs to human gut and emergence of new multidrug resistant clinical isolates. Thus, careful agricultural practices are required especially for plants used in circles of human nutrition industry or in traditional medicine.
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Affiliation(s)
- Ashwag Y. Shami
- Department of Biology, College of Sciences, Princess Nourah bint Abdulrahman University, Riyadh 11617, Saudi Arabia
| | - Aala A. Abulfaraj
- Biological Sciences Department, College of Science and Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia
| | - Mohammed Y. Refai
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Aminah A. Barqawi
- Department of Chemistry, Al-Leith University College, Umm Al Qura University, Makkah, Saudi Arabia
| | - Najat Binothman
- Department of Chemistry, College of Sciences and Arts, King Abdulaziz University, Rabigh, Saudi Arabia
| | - Manal A. Tashkandi
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Hanadi M. Baeissa
- Department of Biochemistry, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Lina Baz
- Department of Biochemistry, Faculty of Science—King Abdulaziz University, Jeddah, Saudi Arabia
| | - Haneen W. Abuauf
- Department of Biology, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Ruba A. Ashy
- Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Rewaa S. Jalal
- Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia
- *Correspondence: Rewaa S. Jalal,
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6
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Otani H, Mouncey NJ. RIViT-seq enables systematic identification of regulons of transcriptional machineries. Nat Commun 2022; 13:3502. [PMID: 35715393 PMCID: PMC9205884 DOI: 10.1038/s41467-022-31191-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 06/06/2022] [Indexed: 11/08/2022] Open
Abstract
Transcriptional regulation is a critical process to ensure expression of genes necessary for growth and survival in diverse environments. Transcription is mediated by multiple transcription factors including activators, repressors and sigma factors. Accurate computational prediction of the regulon of target genes for transcription factors is difficult and experimental identification is laborious and not scalable. Here, we demonstrate regulon identification by in vitro transcription-sequencing (RIViT-seq) that enables systematic identification of regulons of transcription factors by combining an in vitro transcription assay and RNA-sequencing. Using this technology, target genes of 11 sigma factors were identified in Streptomyces coelicolor A3(2). The RIViT-seq data expands the transcriptional regulatory network in this bacterium, discovering regulatory cascades and crosstalk between sigma factors. Implementation of RIViT-seq with other transcription factors and in other organisms will improve our understanding of transcriptional regulatory networks across biology.
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Affiliation(s)
- Hiroshi Otani
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Nigel J Mouncey
- US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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7
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Bednarz B, Millan-Oropeza A, Kotowska M, Świat M, Quispe Haro JJ, Henry C, Pawlik K. Coelimycin Synthesis Activatory Proteins Are Key Regulators of Specialized Metabolism and Precursor Flux in Streptomyces coelicolor A3(2). Front Microbiol 2021; 12:616050. [PMID: 33897632 PMCID: PMC8062868 DOI: 10.3389/fmicb.2021.616050] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 03/17/2021] [Indexed: 11/24/2022] Open
Abstract
Many microbial specialized metabolites are industrially relevant agents but also serve as signaling molecules in intra-species and even inter-kingdom interactions. In the antibiotic-producing Streptomyces, members of the SARP (Streptomyces antibiotic regulatory proteins) family of regulators are often encoded within biosynthetic gene clusters and serve as their direct activators. Coelimycin is the earliest, colored specialized metabolite synthesized in the life cycle of the model organism Streptomyces coelicolor A3(2). Deletion of its two SARP activators cpkO and cpkN abolished coelimycin synthesis and resulted in dramatic changes in the production of the later, stationary-phase antibiotics. The underlying mechanisms of these phenotypes were deregulation of precursor flux and quorum sensing, as shown by label-free, bottom-up shotgun proteomics. Detailed profiling of promoter activities demonstrated that CpkO is the upper-level cluster activator that induces CpkN, while CpkN activates type II thioesterase ScoT, necessary for coelimycin synthesis. What is more, we show that cpkN is regulated by quorum sensing gamma-butyrolactone receptor ScbR.
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Affiliation(s)
- Bartosz Bednarz
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Aaron Millan-Oropeza
- PAPPSO, Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Magdalena Kotowska
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Michał Świat
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Juan J Quispe Haro
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Céline Henry
- PAPPSO, Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Krzysztof Pawlik
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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8
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Dou Y, Rutanhira H, Schormann N, Deivanayagam C, Fletcher HM. PG1659 functions as anti-sigma factor to extracytoplasmic function sigma factor RpoE in Porphyromonas gingivalis W83. Mol Oral Microbiol 2021; 36:80-91. [PMID: 33377315 DOI: 10.1111/omi.12329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022]
Abstract
Anti-sigma factors play a critical role in regulating the expression of sigma factors in response to environmental stress signals. PG1659 is cotranscribed with an upstream gene PG1660 (rpoE), which encodes for a sigma factor that plays an important role in oxidative stress resistance and the virulence regulatory network of P. gingivalis. PG1659, which is annotated as a hypothetical gene, is evaluated in this study. PG1659, composed of 130 amino acids, is predicted to be transmembrane protein with a single calcium (Ca2+ ) binding site. In P. gingivalis FLL358 (ΔPG1659::ermF), the rpoE gene was highly upregulated compared to the wild-type W83 strain. RpoE-induced genes were also upregulated in the PG1659-defective isogenic mutant. Both protein-protein pull-down and bacterial two-hybrid assays revealed that the PG1659 protein could interact with/bind RpoE. The N-terminal domain of PG1659, representing the cytoplasmic fragment of the protein, is critical for interaction with RpoE. In the presence of PG1659, the initiation of transcription by the RpoE sigma factor was inhibited. Taken together, our data suggest that PG1659 is an anti-sigma factor which plays an important regulatory role in the modulation of the sigma factor RpoE in P. gingivalis.
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Affiliation(s)
- Yuetan Dou
- Department of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Hiel Rutanhira
- Department of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Norbert Schormann
- Department of Biochemistry and Molecular Genetics, School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Champion Deivanayagam
- Department of Biochemistry and Molecular Genetics, School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hansel M Fletcher
- Department of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA, USA
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9
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Vishwakarma RK, Brodolin K. The σ Subunit-Remodeling Factors: An Emerging Paradigms of Transcription Regulation. Front Microbiol 2020; 11:1798. [PMID: 32849409 PMCID: PMC7403470 DOI: 10.3389/fmicb.2020.01798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/09/2020] [Indexed: 11/13/2022] Open
Abstract
Transcription initiation is a key checkpoint and highly regulated step of gene expression. The sigma (σ) subunit of RNA polymerase (RNAP) controls all transcription initiation steps, from recognition of the -10/-35 promoter elements, upon formation of the closed promoter complex (RPc), to stabilization of the open promoter complex (RPo) and stimulation of the primary steps in RNA synthesis. The canonical mechanism to regulate σ activity upon transcription initiation relies on activators that recognize specific DNA motifs and recruit RNAP to promoters. This mini-review describes an emerging group of transcriptional regulators that form a complex with σ or/and RNAP prior to promoter binding, remodel the σ subunit conformation, and thus modify RNAP activity. Such strategy is widely used by bacteriophages to appropriate the host RNAP. Recent findings on RNAP-binding protein A (RbpA) from Mycobacterium tuberculosis and Crl from Escherichia coli suggest that activator-driven changes in σ conformation can be a widespread regulatory mechanism in bacteria.
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Affiliation(s)
- Rishi Kishore Vishwakarma
- Institut de Recherche en Infectiologie de Montpellier, CNRS, Université de Montpellier, Montpellier, France
| | - Konstantin Brodolin
- Institut de Recherche en Infectiologie de Montpellier, CNRS, Université de Montpellier, Montpellier, France
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10
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Schäfer H, Beckert B, Frese CK, Steinchen W, Nuss AM, Beckstette M, Hantke I, Driller K, Sudzinová P, Krásný L, Kaever V, Dersch P, Bange G, Wilson DN, Turgay K. The alarmones (p)ppGpp are part of the heat shock response of Bacillus subtilis. PLoS Genet 2020; 16:e1008275. [PMID: 32176689 PMCID: PMC7098656 DOI: 10.1371/journal.pgen.1008275] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 03/26/2020] [Accepted: 02/26/2020] [Indexed: 11/24/2022] Open
Abstract
Bacillus subtilis cells are well suited to study how bacteria sense and adapt to proteotoxic stress such as heat, since temperature fluctuations are a major challenge to soil-dwelling bacteria. Here, we show that the alarmones (p)ppGpp, well known second messengers of nutrient starvation, are also involved in the heat stress response as well as the development of thermo-resistance. Upon heat-shock, intracellular levels of (p)ppGpp rise in a rapid but transient manner. The heat-induced (p)ppGpp is primarily produced by the ribosome-associated alarmone synthetase Rel, while the small alarmone synthetases RelP and RelQ seem not to be involved. Furthermore, our study shows that the generated (p)ppGpp pulse primarily acts at the level of translation, and only specific genes are regulated at the transcriptional level. These include the down-regulation of some translation-related genes and the up-regulation of hpf, encoding the ribosome-protecting hibernation-promoting factor. In addition, the alarmones appear to interact with the activity of the stress transcription factor Spx during heat stress. Taken together, our study suggests that (p)ppGpp modulates the translational capacity at elevated temperatures and thereby allows B. subtilis cells to respond to proteotoxic stress, not only by raising the cellular repair capacity, but also by decreasing translation to concurrently reduce the protein load on the cellular protein quality control system.
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Affiliation(s)
- Heinrich Schäfer
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | - Bertrand Beckert
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | | | - Wieland Steinchen
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Marburg, Germany
| | - Aaron M. Nuss
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Beckstette
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ingo Hantke
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
| | | | - Petra Sudzinová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Volkhard Kaever
- Hannover Medical School, Research Core Unit Metabolomics, Hannover, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute of Infectiology, University of Münster, Münster, Germany
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Marburg, Germany
| | - Daniel N. Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Kürşad Turgay
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
- Max Planck Unit for the Science of Pathogens, Berlin, Germany
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11
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Pinto D, da Fonseca RR. Evolution of the extracytoplasmic function σ factor protein family. NAR Genom Bioinform 2020; 2:lqz026. [PMID: 33575573 PMCID: PMC7671368 DOI: 10.1093/nargab/lqz026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/04/2019] [Accepted: 12/19/2019] [Indexed: 12/18/2022] Open
Abstract
Understanding transcription has been a central goal of the scientific community for decades. However, much is still unknown, especially concerning how it is regulated. In bacteria, a single DNA-directed RNA-polymerase performs the whole of transcription. It contains multiple subunits, among which the σ factor that confers promoter specificity. Besides the housekeeping σ factor, bacteria encode several alternative σ factors. The most abundant and diverse family of alternative σ factors, the extracytoplasmic function (ECF) family, regulates transcription of genes associated with stressful scenarios, making them key elements of adaptation to specific environmental changes. Despite this, the evolutionary history of ECF σ factors has never been investigated. Here, we report on our analysis of thousands of members of this family. We show that single events are in the origin of alternative modes of regulation of ECF σ factor activity that require partner proteins, but that multiple events resulted in acquisition of regulatory extensions. Moreover, in Bacteroidetes there is a recent duplication of an ecologically relevant gene cluster that includes an ECF σ factor, whereas in Planctomycetes duplication generates distinct C-terminal extensions after fortuitous insertion of the duplicated σ factor. At last, we also demonstrate horizontal transfer of ECF σ factors between soil bacteria.
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Affiliation(s)
- Daniela Pinto
- Technische Universität Dresden, Institute of Microbiology, Zellescher Weg 20b, 01217 Dresden, Germany
| | - Rute R da Fonseca
- Center for Macroecology, Evolution and Climate (CMEC), GLOBE Institute, University of Copenhagen, 1350 Copenhagen K, Denmark
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12
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Boyaci H, Saecker RM, Campbell EA. Transcription initiation in mycobacteria: a biophysical perspective. Transcription 2019; 11:53-65. [PMID: 31880185 DOI: 10.1080/21541264.2019.1707612] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Recent biophysical studies of mycobacterial transcription have shed new light on this fundamental process in a group of bacteria that includes deadly pathogens such as Mycobacterium tuberculosis (Mtb), Mycobacterium abscessus (Mab), Mycobacterium leprae (Mlp), as well as the nonpathogenic Mycobacterium smegmatis (Msm). Most of the research has focused on Mtb, the causative agent of tuberculosis (TB), which remains one of the top ten causes of death globally. The enzyme RNA polymerase (RNAP) is responsible for all bacterial transcription and is a target for one of the crucial antibiotics used for TB treatment, rifampicin (Rif). Here, we summarize recent biophysical studies of mycobacterial RNAP that have advanced our understanding of the basic process of transcription, have revealed novel paradigms for regulation, and thus have provided critical information required for developing new antibiotics against this deadly disease.
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Affiliation(s)
- Hande Boyaci
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
| | - Ruth M Saecker
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University , New York, NY, USA
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13
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Šmídová K, Ziková A, Pospíšil J, Schwarz M, Bobek J, Vohradsky J. DNA mapping and kinetic modeling of the HrdB regulon in Streptomyces coelicolor. Nucleic Acids Res 2019; 47:621-633. [PMID: 30371884 PMCID: PMC6344877 DOI: 10.1093/nar/gky1018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/11/2018] [Indexed: 02/06/2023] Open
Abstract
HrdB in streptomycetes is a principal sigma factor whose deletion is lethal. This is also the reason why its regulon has not been investigated so far. To overcome experimental obstacles, for investigating the HrdB regulon, we constructed a strain whose HrdB protein was tagged by an HA epitope. ChIP-seq experiment, done in 3 repeats, identified 2137 protein-coding genes organized in 337 operons, 75 small RNAs, 62 tRNAs, 6 rRNAs and 3 miscellaneous RNAs. Subsequent kinetic modeling of regulation of protein-coding genes with HrdB alone and with a complex of HrdB and a transcriptional cofactor RbpA, using gene expression time series, identified 1694 genes that were under their direct control. When using the HrdB-RbpA complex in the model, an increase of the model fidelity was found for 322 genes. Functional analysis revealed that HrdB controls the majority of gene groups essential for the primary metabolism and the vegetative growth. Particularly, almost all ribosomal protein-coding genes were found in the HrdB regulon. Analysis of promoter binding sites revealed binding motif at the -10 region and suggested the possible role of mono- or di-nucleotides upstream of the -10 element.
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Affiliation(s)
- Klára Šmídová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czechia
- First Faculty of Medicine, Institute of Immunology and Microbiology, Charles University, 12800 Prague, Czechia
| | - Alice Ziková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czechia
| | - Jiří Pospíšil
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czechia
| | - Marek Schwarz
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czechia
| | - Jan Bobek
- First Faculty of Medicine, Institute of Immunology and Microbiology, Charles University, 12800 Prague, Czechia
- Chemistry Department, Faculty of Science, J. E. Purkinje University, 40096 Ústí nad Labem, Czechia
| | - Jiri Vohradsky
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 14220 Prague, Czechia
- To whom correspondence should be addressed. Tel: +420 241 062 513;
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14
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Abstract
This year marks the 50th anniversary of the discovery of σ70 as a protein factor that was needed for bacterial RNA polymerase to accurately transcribe a promoter in vitro. It was 25 years later that the Group IV alternative σs were described as a distinct family of proteins related to σ70 . In the intervening time, there has been an ever-growing list of Group IV σs, numbers of genes they transcribe, insight into the diverse suite of processes they control, and appreciation for their impact on bacterial lifestyles. This work summarizes knowledge of the Rhodobacter sphaeroides σE -ChrR pair, a member of the ECF11 subfamily of Group IV alternative σs, in protecting cells from the reactive oxygen species, singlet oxygen. It describes lessons learned from analyzing ChrR, a zinc-dependent anti-σ factor, that are generally applicable to Group IV σs and relevant to the response to single oxygen. This MicroReview also illustrates insights into stress responses in this and other bacteria that have been acquired by analyzing or modeling the activity of the σE -ChrR across the bacterial phylogeny.
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Affiliation(s)
- Timothy J. Donohue
- Bacteriology Department, Great Lakes Bioenergy Research CenterWisconsin Energy Institute, University of Wisconsin‐MadisonMadisonWI53726USA
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15
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Park JH, Lee JH, Roe JH. SigR, a hub of multilayered regulation of redox and antibiotic stress responses. Mol Microbiol 2019; 112:420-431. [PMID: 31269533 DOI: 10.1111/mmi.14341] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2019] [Indexed: 02/01/2023]
Abstract
Signal-specific activation of alternative sigma factors redirects RNA polymerase to induce transcription of distinct sets of genes conferring protection against the damage the signal and the related stresses incur. In Streptomyces coelicolor, σR (SigR), a member of ECF12 subfamily of Group IV sigma factors, responds to thiol-perturbing signals such as oxidants and electrophiles, as well as to translation-blocking antibiotics. Oxidants and electrophiles interact with and inactivate the zinc-containing anti-sigma factor, RsrA, via disulfide bond formation or alkylation of reactive cysteines, subsequently releasing σR for target gene induction. Translation-blocking antibiotics induce the synthesis of σR , via the WhiB-like transcription factor, WblC/WhiB7. Signal transduction via RsrA produces a dramatic transient response that involves positive feedback to produce more SigR as an unstable isoform σ R ' and negative feedbacks to degrade σ R ' , and reduce oxidized RsrA that subsequently sequester σR and σ R ' . Antibiotic stress brings about a prolonged response by increasing stable σR levels. The third negative feedback, which occurs via IF3, lowers the translation efficiency of the sigRp1 transcript that utilizes a non-canonical start codon. σR is a global regulator that directly activates > 100 transcription units in S. coelicolor, including genes for thiol homeostasis, protein quality control, sulfur metabolism, ribosome modulation and DNA repair. Close homologues in Actinobacteria, such as σH in Mycobacteria and Corynebacteria, show high conservation of the signal transduction pathways and target genes, thus reflecting the robustness of this type of regulation in response to redox and antibiotic stresses.
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Affiliation(s)
- Joo-Hong Park
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Ju-Hyung Lee
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Jung-Hye Roe
- School of Biological Sciences, and Institute of Microbiology, College of Natural Sciences, Seoul National University, Seoul, Korea
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16
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Bucca G, Pothi R, Hesketh A, Möller-Levet C, Hodgson DA, Laing EE, Stewart GR, Smith CP. Translational control plays an important role in the adaptive heat-shock response of Streptomyces coelicolor. Nucleic Acids Res 2019; 46:5692-5703. [PMID: 29746664 PMCID: PMC6009599 DOI: 10.1093/nar/gky335] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 04/18/2018] [Indexed: 12/29/2022] Open
Abstract
Stress-induced adaptations require multiple levels of regulation in all organisms to repair cellular damage. In the present study we evaluated the genome-wide transcriptional and translational changes following heat stress exposure in the soil-dwelling model actinomycete bacterium, Streptomyces coelicolor. The combined analysis revealed an unprecedented level of translational control of gene expression, deduced through polysome profiling, in addition to transcriptional changes. Our data show little correlation between the transcriptome and ‘translatome’; while an obvious downward trend in genome wide transcription was observed, polysome associated transcripts following heat-shock showed an opposite upward trend. A handful of key protein players, including the major molecular chaperones and proteases were highly induced at both the transcriptional and translational level following heat-shock, a phenomenon known as ‘potentiation’. Many other transcripts encoding cold-shock proteins, ABC-transporter systems, multiple transcription factors were more highly polysome-associated following heat stress; interestingly, these protein families were not induced at the transcriptional level and therefore were not previously identified as part of the stress response. Thus, stress coping mechanisms at the level of gene expression in this bacterium go well beyond the induction of a relatively small number of molecular chaperones and proteases in order to ensure cellular survival at non-physiological temperatures.
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Affiliation(s)
- Giselda Bucca
- School of Pharmacy and Biomolecular Sciences, University of Brighton, UK
| | - Radhika Pothi
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, UK
| | - Andrew Hesketh
- School of Pharmacy and Biomolecular Sciences, University of Brighton, UK
| | - Carla Möller-Levet
- Bioinformatics facility, Faculty of Health and Medical Sciences, University of Surrey, UK
| | | | - Emma E Laing
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, UK
| | - Graham R Stewart
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, UK
| | - Colin P Smith
- School of Pharmacy and Biomolecular Sciences, University of Brighton, UK
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17
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Pinto D, Liu Q, Mascher T. ECF σ factors with regulatory extensions: the one-component systems of the σ universe. Mol Microbiol 2019; 112:399-409. [PMID: 31175685 DOI: 10.1111/mmi.14323] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2019] [Indexed: 12/18/2022]
Abstract
The σ subunit of the bacterial RNA polymerase determines promoter specificity. The extracytoplasmic function σ factors (ECFs) represent the most abundant and diverse group of alternative σ factors and are present in the vast majority of bacterial genomes. Typically, ECFs are regulated by anti-σ factors that sequester their cognate ECFs, thereby preventing their interaction with the RNA polymerase. Beyond these ECF paradigms, a number of distinct modes of regulation have been proposed and experimentally investigated. Regulatory extensions represent one such alternative mechanism of ECF regulation that can be found in 18 phylogenetically distinct ECF groups. Here, the σ factors contain additional domains that are fused to the ECF core domains and are involved in stimulus perception and modulation of σ factor activity. We will summarize the current state of knowledge on regulating ECF activity by C-terminal extensions. We will also discuss newly identified ECF groups containing either N- or C-terminal extensions and propose possible mechanisms by which these extensions have been generated and affect ECF σ factor activity. Based on their modular architecture and the resulting physical connection between stimulus perception and transcriptional output, these ECFs are analogous to one-component systems, the primary mechanism of bacterial signal transduction.
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Affiliation(s)
- Daniela Pinto
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany
| | - Qiang Liu
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany.,Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01217, Dresden, Germany
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18
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Lonetto MA, Donohue TJ, Gross CA, Buttner MJ. Discovery of the extracytoplasmic function σ factors. Mol Microbiol 2019; 112:348-355. [PMID: 31115926 DOI: 10.1111/mmi.14307] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2019] [Indexed: 12/14/2022]
Abstract
This special issue of Molecular Microbiology marks the 25th anniversary of the discovery of the extracytoplasmic function (ECF) σ factors, proteins that subsequently emerged as the largest group of alternative σ factors and one of the three major pillars of signal transduction in bacteria, alongside one- and two-component systems. A single bacterial genome can encode > 100 ECF σ factors, and combined with their cognate anti-σ factors, they represent a modular design that primarily functions in transmembrane signal transduction. Here, we first describe the immediate events that led to the 1994 publication in the Proceeding of the National Academy of Sciences USA, and then set them in the broader context of key events in the history of σ biology research.
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Affiliation(s)
- Michael A Lonetto
- Department of Informatics, Novartis Institutes for BioMedical Research, Cambridge, MA, 02139, USA
| | - Timothy J Donohue
- Department of Bacteriology, Wisconsin Energy Institute, University of Wisconsin, Madison, WI, 53706, USA
| | - Carol A Gross
- Department of Microbiology and Immunology and Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Mark J Buttner
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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19
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Tran NT, Huang X, Hong HJ, Bush MJ, Chandra G, Pinto D, Bibb MJ, Hutchings MI, Mascher T, Buttner MJ. Defining the regulon of genes controlled by σ E , a key regulator of the cell envelope stress response in Streptomyces coelicolor. Mol Microbiol 2019; 112:461-481. [PMID: 30907454 PMCID: PMC6767563 DOI: 10.1111/mmi.14250] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2019] [Indexed: 01/01/2023]
Abstract
The extracytoplasmic function (ECF) σ factor, σE , is a key regulator of the cell envelope stress response in Streptomyces coelicolor. Although its role in maintaining cell wall integrity has been known for over a decade, a comprehensive analysis of the genes under its control has not been undertaken. Here, using a combination of chromatin immunoprecipitation-sequencing (ChIP-seq), microarray transcriptional profiling and bioinformatic analysis, we attempt to define the σE regulon. Approximately half of the genes identified encode proteins implicated in cell envelope function. Seventeen novel targets were validated by S1 nuclease mapping or in vitro transcription, establishing a σE -binding consensus. Subsequently, we used bioinformatic analysis to look for conservation of the σE target promoters identified in S. coelicolor across 19 Streptomyces species. Key proteins under σE control across the genus include the actin homolog MreB, three penicillin-binding proteins, two L,D-transpeptidases, a LytR-CpsA-Psr-family protein predicted to be involved in cell wall teichoic acid deposition and a predicted MprF protein, which adds lysyl groups to phosphatidylglycerol to neutralize membrane surface charge. Taken together, these analyses provide biological insight into the σE -mediated cell envelope stress response in the genus Streptomyces.
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Affiliation(s)
- Ngat T Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Xiaoluo Huang
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.,Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Hee-Jeon Hong
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Daniela Pinto
- Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Maureen J Bibb
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Matthew I Hutchings
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Thorsten Mascher
- Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Mark J Buttner
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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20
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Bush MJ. The actinobacterial WhiB-like (Wbl) family of transcription factors. Mol Microbiol 2018; 110:663-676. [PMID: 30179278 PMCID: PMC6282962 DOI: 10.1111/mmi.14117] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 02/06/2023]
Abstract
The WhiB‐like (Wbl) family of proteins are exclusively found in Actinobacteria. Wbls have been shown to play key roles in virulence and antibiotic resistance in Mycobacteria and Corynebacteria, reflecting their importance during infection by the human pathogens Mycobacterium tuberculosis, Mycobacterium leprae and Corynebacterium diphtheriae. In the antibiotic‐producing Streptomyces, several Wbls have important roles in the regulation of morphological differentiation, including WhiB, a protein that controls the initiation of sporulation septation and the founding member of the Wbl family. In recent years, genome sequencing has revealed the prevalence of Wbl paralogues in species throughout the Actinobacteria. Wbl proteins are small (generally ~80–140 residues) and each contains four invariant cysteine residues that bind an O2‐ and NO‐sensitive [4Fe–4S] cluster, raising the question as to how they can maintain distinct cellular functions within a given species. Despite their discovery over 25 years ago, the Wbl protein family has largely remained enigmatic. Here I summarise recent research in Mycobacteria, Corynebacteria and Streptomyces that sheds light on the biochemical function of Wbls as transcription factors and as potential sensors of O2 and NO. I suggest that Wbl evolution has created diversity in protein–protein interactions, [4Fe–4S] cluster‐sensitivity and the ability to bind DNA.
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Affiliation(s)
- Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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21
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Prusa J, Jensen D, Santiago-Collazo G, Pope SS, Garner AL, Miller JJ, Ruiz Manzano A, Galburt EA, Stallings CL. Domains within RbpA Serve Specific Functional Roles That Regulate the Expression of Distinct Mycobacterial Gene Subsets. J Bacteriol 2018; 200:e00690-17. [PMID: 29686140 PMCID: PMC5996690 DOI: 10.1128/jb.00690-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 04/18/2018] [Indexed: 11/20/2022] Open
Abstract
The RNA polymerase (RNAP) binding protein A (RbpA) contributes to the formation of stable RNAP-promoter open complexes (RPo) and is essential for viability in mycobacteria. Four domains have been identified in the RbpA protein, i.e., an N-terminal tail (NTT) that interacts with RNAP β' and σ subunits, a core domain (CD) that contacts the RNAP β' subunit, a basic linker (BL) that binds DNA, and a σ-interaction domain (SID) that binds group I and group II σ factors. Limited in vivo studies have been performed in mycobacteria, however, and how individual structural domains of RbpA contribute to RbpA function and mycobacterial gene expression remains mostly unknown. We investigated the roles of the RbpA structural domains in mycobacteria using a panel of rbpA mutants that target individual RbpA domains. The function of each RbpA domain was required for Mycobacterium tuberculosis viability and optimal growth in Mycobacterium smegmatis We determined that the RbpA SID is both necessary and sufficient for RbpA interaction with the RNAP, indicating that the primary functions of the NTT and CD are not solely association with the RNAP. We show that the RbpA BL and SID are required for RPo stabilization in vitro, while the NTT and CD antagonize this activity. Finally, RNA-sequencing analyses suggest that the NTT and CD broadly activate gene expression, whereas the BL and SID activate or repress gene expression in a gene-dependent manner for a subset of mycobacterial genes. Our findings highlight specific outcomes for the activities of the individual functional domains in RbpA.IMPORTANCEMycobacterium tuberculosis is the causative agent of tuberculosis and continues to be the most lethal infectious disease worldwide. Improved molecular understanding of the essential proteins involved in M. tuberculosis transcription, such as RbpA, could provide targets for much needed future therapeutic agents aimed at combatting this pathogen. In this study, we expand our understanding of RbpA by identifying the RbpA structural domains responsible for the interaction of RbpA with the RNAP and the effects of RbpA on transcription initiation and gene expression. These experiments expand our knowledge of RbpA while also broadening our understanding of bacterial transcription in general.
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Affiliation(s)
- Jerome Prusa
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Drake Jensen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gustavo Santiago-Collazo
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Steven S Pope
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ashley L Garner
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Justin J Miller
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ana Ruiz Manzano
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eric A Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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22
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Differential RNA Sequencing Implicates Sulfide as the Master Regulator of S 0 Metabolism in Chlorobaculum tepidum and Other Green Sulfur Bacteria. Appl Environ Microbiol 2018; 84:AEM.01966-17. [PMID: 29150516 DOI: 10.1128/aem.01966-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/14/2017] [Indexed: 12/23/2022] Open
Abstract
The green sulfur bacteria (Chlorobiaceae) are anaerobes that use electrons from reduced sulfur compounds (sulfide, S0, and thiosulfate) as electron donors for photoautotrophic growth. Chlorobaculum tepidum, the model system for the Chlorobiaceae, both produces and consumes extracellular S0 globules depending on the availability of sulfide in the environment. These physiological changes imply significant changes in gene regulation, which has been observed when sulfide is added to Cba. tepidum growing on thiosulfate. However, the underlying mechanisms driving these gene expression changes, i.e., the specific regulators and promoter elements involved, have not yet been defined. Here, differential RNA sequencing (dRNA-seq) was used to globally identify transcript start sites (TSS) that were present during growth on sulfide, biogenic S0, and thiosulfate as sole electron donors. TSS positions were used in combination with RNA-seq data from cultures growing on these same electron donors to identify both basal promoter elements and motifs associated with electron donor-dependent transcriptional regulation. These motifs were conserved across homologous Chlorobiaceae promoters. Two lines of evidence suggest that sulfide-mediated repression is the dominant regulatory mode in Cba. tepidum First, motifs associated with genes regulated by sulfide overlap key basal promoter elements. Second, deletion of the Cba. tepidum1277 (CT1277) gene, encoding a putative regulatory protein, leads to constitutive overexpression of the sulfide:quinone oxidoreductase CT1087 in the absence of sulfide. The results suggest that sulfide is the master regulator of sulfur metabolism in Cba. tepidum and the Chlorobiaceae Finally, the identification of basal promoter elements with differing strengths will further the development of synthetic biology in Cba. tepidum and perhaps other ChlorobiaceaeIMPORTANCE Elemental sulfur is a key intermediate in biogeochemical sulfur cycling. The photoautotrophic green sulfur bacterium Chlorobaculum tepidum either produces or consumes elemental sulfur depending on the availability of sulfide in the environment. Our results reveal transcriptional dynamics of Chlorobaculum tepidum on elemental sulfur and increase our understanding of the mechanisms of transcriptional regulation governing growth on different reduced sulfur compounds. This report identifies genes and sequence motifs that likely play significant roles in the production and consumption of elemental sulfur. Beyond this focused impact, this report paves the way for the development of synthetic biology in Chlorobaculum tepidum and other Chlorobiaceae by providing a comprehensive identification of promoter elements for control of gene expression, a key element of strain engineering.
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Sun D, Liu C, Zhu J, Liu W. Connecting Metabolic Pathways: Sigma Factors in Streptomyces spp. Front Microbiol 2017; 8:2546. [PMID: 29312231 PMCID: PMC5742136 DOI: 10.3389/fmicb.2017.02546] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/07/2017] [Indexed: 11/13/2022] Open
Abstract
The gram-positive filamentous bacterium Streptomyces is one of the largest resources for bioactive metabolites, particularly antibiotics. Antibiotic production and other metabolic processes are tightly regulated at the transcriptional level. Sigma (σ) factors are components of bacterial RNA polymerases that determine promoter specificity. In Streptomyces, σ factors also play essential roles in signal transduction and in regulatory networks, thereby assisting in their survival in complex environments. However, our current understanding of σ factors in Streptomyces is still limited. In this mini-review, we demonstrate the roles of Streptomyces σ factors, illustrating that these serve as linkers of different metabolic pathways. Further investigations on σ factors may improve our knowledge of Streptomyces physiology and benefit exploitation of Streptomyces resources.
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Affiliation(s)
- Di Sun
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Cong Liu
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Jingrong Zhu
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Weijie Liu
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
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24
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Oshone R, Ngom M, Chu F, Mansour S, Sy MO, Champion A, Tisa LS. Genomic, transcriptomic, and proteomic approaches towards understanding the molecular mechanisms of salt tolerance in Frankia strains isolated from Casuarina trees. BMC Genomics 2017; 18:633. [PMID: 28821232 PMCID: PMC5563000 DOI: 10.1186/s12864-017-4056-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/11/2017] [Indexed: 11/10/2022] Open
Abstract
Background Soil salinization is a worldwide problem that is intensifying because of the effects of climate change. An effective method for the reclamation of salt-affected soils involves initiating plant succession using fast growing, nitrogen fixing actinorhizal trees such as the Casuarina. The salt tolerance of Casuarina is enhanced by the nitrogen-fixing symbiosis that they form with the actinobacterium Frankia. Identification and molecular characterization of salt-tolerant Casuarina species and associated Frankia is imperative for the successful utilization of Casuarina trees in saline soil reclamation efforts. In this study, salt-tolerant and salt-sensitive Casuarina associated Frankia strains were identified and comparative genomics, transcriptome profiling, and proteomics were employed to elucidate the molecular mechanisms of salt and osmotic stress tolerance. Results Salt-tolerant Frankia strains (CcI6 and Allo2) that could withstand up to 1000 mM NaCl and a salt-sensitive Frankia strain (CcI3) which could withstand only up to 475 mM NaCl were identified. The remaining isolates had intermediate levels of salt tolerance with MIC values ranging from 650 mM to 750 mM. Comparative genomic analysis showed that all of the Frankia isolates from Casuarina belonged to the same species (Frankia casuarinae). Pangenome analysis revealed a high abundance of singletons among all Casuarina isolates. The two salt-tolerant strains contained 153 shared single copy genes (most of which code for hypothetical proteins) that were not found in the salt-sensitive(CcI3) and moderately salt-tolerant (CeD) strains. RNA-seq analysis of one of the two salt-tolerant strains (Frankia sp. strain CcI6) revealed hundreds of genes differentially expressed under salt and/or osmotic stress. Among the 153 genes, 7 and 7 were responsive to salt and osmotic stress, respectively. Proteomic profiling confirmed the transcriptome results and identified 19 and 8 salt and/or osmotic stress-responsive proteins in the salt-tolerant (CcI6) and the salt-sensitive (CcI3) strains, respectively. Conclusion Genetic differences between salt-tolerant and salt-sensitive Frankia strains isolated from Casuarina were identified. Transcriptome and proteome profiling of a salt-tolerant strain was used to determine molecular differences correlated with differential salt-tolerance and several candidate genes were identified. Mechanisms involving transcriptional and translational regulation, cell envelop remodeling, and previously uncharacterized proteins appear to be important for salt tolerance. Physiological and mutational analyses will further shed light on the molecular mechanism of salt tolerance in Casuarina associated Frankia isolates. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-4056-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rediet Oshone
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Rd, Durham, NH, 03824-2617, USA
| | - Mariama Ngom
- Laboratoire Mixte International Adaptation des Plantes et microorganismes associés aux Stress Environnementaux, Centre de Recherche de Bel-Air, Dakar, Sénégal.,Laboratoire Campus de Biotechnologies Végétales, Département de Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal.,Laboratoire Commun de Microbiologie Institut de Recherche pour le Développement/Institut Sénégalais de Recherches Agricoles/Université Cheikh Anta Diop, Centre de Recherche de Bel-Air, Dakar, Sénégal
| | - Feixia Chu
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Rd, Durham, NH, 03824-2617, USA
| | - Samira Mansour
- Faculty of Science, Suez Canal University, Ismalia, Egypt
| | - Mame Ourèye Sy
- Laboratoire Mixte International Adaptation des Plantes et microorganismes associés aux Stress Environnementaux, Centre de Recherche de Bel-Air, Dakar, Sénégal.,Laboratoire Campus de Biotechnologies Végétales, Département de Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Antony Champion
- Laboratoire Mixte International Adaptation des Plantes et microorganismes associés aux Stress Environnementaux, Centre de Recherche de Bel-Air, Dakar, Sénégal.,UMR DIADE, Institut de Recherche pour le Développement, Montpellier, France
| | - Louis S Tisa
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Rd, Durham, NH, 03824-2617, USA.
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Bauer JS, Fillinger S, Förstner K, Herbig A, Jones AC, Flinspach K, Sharma C, Gross H, Nieselt K, Apel AK. dRNA-seq transcriptional profiling of the FK506 biosynthetic gene cluster in Streptomyces tsukubaensis NRRL18488 and general analysis of the transcriptome. RNA Biol 2017; 14:1617-1626. [PMID: 28665778 DOI: 10.1080/15476286.2017.1341020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
FK506 (tacrolimus) is a valuable immunosuppressant produced by several Streptomyces strains. In the genome of the wild type producer Streptomyces tsukubaensis NRRL18488, FK506 biosynthesis is encoded by a gene cluster that spans 83.5 (kb). A whole transcriptome differential shotgun sequencing (dRNA-seq) of S. tsukubaensis was performed to analyze transcription at 2 different time points; before and during active FK506 production. In total, 8,914 transcription start sites were identified in either condition, which enabled precise determination of the 5'-UTR length of the corresponding transcripts as well as the identification of 2 consensus sequence motifs in the promoter regions. The transcription start sites of all gene operons within the FK506 cluster were identified, including 3 examples of leaderless RNA transcripts. These data provide detailed insight into the transcription of the FK506 biosynthetic gene cluster to support future regulatory studies, genetic manipulation, and industrial production.
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Affiliation(s)
- Judith S Bauer
- a Pharmaceutical Institute, Department of Pharmaceutical Biology , University of Tübingen , Tübingen , Germany.,b German Centre for Infection Research (DZIF), Partner Site Tübingen , Tübingen , Germany
| | - Sven Fillinger
- c Integrative Transcriptomics, Center for Bioinformatics Tübingen, University of Tübingen , Germany
| | - Konrad Förstner
- e Research Center for Infectious Diseases , University of Würzburg , Würzburg , Germany , Core Unit Systems Medicine , Institute for Molecular Infection Biology, University of Würzburg , Würzburg , Germany
| | - Alexander Herbig
- d Max Planck Institute for the Science of Human History , Jena , Germany
| | - Adam C Jones
- a Pharmaceutical Institute, Department of Pharmaceutical Biology , University of Tübingen , Tübingen , Germany
| | - Katrin Flinspach
- a Pharmaceutical Institute, Department of Pharmaceutical Biology , University of Tübingen , Tübingen , Germany
| | - Cynthia Sharma
- e Research Center for Infectious Diseases , University of Würzburg , Würzburg , Germany , Core Unit Systems Medicine , Institute for Molecular Infection Biology, University of Würzburg , Würzburg , Germany
| | - Harald Gross
- a Pharmaceutical Institute, Department of Pharmaceutical Biology , University of Tübingen , Tübingen , Germany.,b German Centre for Infection Research (DZIF), Partner Site Tübingen , Tübingen , Germany
| | - Kay Nieselt
- c Integrative Transcriptomics, Center for Bioinformatics Tübingen, University of Tübingen , Germany
| | - Alexander K Apel
- a Pharmaceutical Institute, Department of Pharmaceutical Biology , University of Tübingen , Tübingen , Germany.,b German Centre for Infection Research (DZIF), Partner Site Tübingen , Tübingen , Germany
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Translational Control of the SigR-Directed Oxidative Stress Response in Streptomyces via IF3-Mediated Repression of a Noncanonical GTC Start Codon. mBio 2017; 8:mBio.00815-17. [PMID: 28611250 PMCID: PMC5472188 DOI: 10.1128/mbio.00815-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The major oxidative stress response in Streptomyces is controlled by the sigma factor SigR and its cognate antisigma factor RsrA, and SigR activity is tightly controlled through multiple mechanisms at both the transcriptional and posttranslational levels. Here we show that sigR has a highly unusual GTC start codon and that this leads to another level of SigR regulation, in which SigR translation is repressed by translation initiation factor 3 (IF3). Changing the GTC to a canonical start codon causes SigR to be overproduced relative to RsrA, resulting in unregulated and constitutive expression of the SigR regulon. Similarly, introducing IF3* mutations that impair its ability to repress SigR translation has the same effect. Thus, the noncanonical GTC sigR start codon and its repression by IF3 are critical for the correct and proper functioning of the oxidative stress regulatory system. sigR and rsrA are cotranscribed and translationally coupled, and it had therefore been assumed that SigR and RsrA are produced in stoichiometric amounts. Here we show that RsrA can be transcribed and translated independently of SigR, present evidence that RsrA is normally produced in excess of SigR, and describe the factors that determine SigR-RsrA stoichiometry. In all sigma factor-antisigma factor regulatory switches, the relative abundance of the two proteins is critical to the proper functioning of the system. Many sigma-antisigma operons are cotranscribed and translationally coupled, leading to a generic assumption that the sigma and antisigma factors are produced in a fixed 1:1 ratio. In the case of sigR-rsrA, we show instead that the antisigma factor is produced in excess over the sigma factor, providing a buffer to prevent spurious release of sigma activity. This excess arises in part because sigR has an extremely rare noncanonical GTC start codon, and as a result, SigR translation initiation is repressed by IF3. This finding highlights the potential significance of noncanonical start codons, very few of which have been characterized experimentally. It also emphasizes the limitations of predicting start codons using bioinformatic approaches, which rely heavily on the assumption that ATG, GTG, and TTG are the only permissible start codons.
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27
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Structural insights into the regulation of Bacillus subtilis SigW activity by anti-sigma RsiW. PLoS One 2017; 12:e0174284. [PMID: 28319136 PMCID: PMC5358783 DOI: 10.1371/journal.pone.0174284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/06/2017] [Indexed: 11/19/2022] Open
Abstract
Bacillus subtilis SigW is localized to the cell membrane and is inactivated by the tight interaction with anti-sigma RsiW under normal growth conditions. Whereas SigW is discharged from RsiW binding and thus initiates the transcription of its regulon under diverse stress conditions such as antibiotics and alkaline shock. The release and activation of SigW in response to extracytoplasmic signals is induced by the regulated intramembrane proteolysis of RsiW. As a ZAS (Zinc-containing anti-sigma) family protein, RsiW has a CHCC zinc binding motif, which implies that its anti-sigma activity may be regulated by the state of zinc coordination in addition to the proteolytic cleavage of RsiW. To understand the regulation mode of SigW activity by RsiW, we determined the crystal structures of SigW in complex with the cytoplasmic domain of RsiW, and compared the conformation of the CHCC motif in the reduced/zinc binding and the oxidized states. The structures revealed that RsiW inhibits the promoter binding of SigW by interacting with the surface groove of SigW. The interaction between SigW and RsiW is not disrupted by the oxidation of the CHCC motif in RsiW, suggesting that SigW activity might not be regulated by the zinc coordination states of the CHCC motif.
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28
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Esteban-Torres M, Reverón I, Plaza-Vinuesa L, de las Rivas B, Muñoz R, López de Felipe F. Transcriptional Reprogramming at Genome-Scale of Lactobacillus plantarum WCFS1 in Response to Olive Oil Challenge. Front Microbiol 2017; 8:244. [PMID: 28261192 PMCID: PMC5313477 DOI: 10.3389/fmicb.2017.00244] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/03/2017] [Indexed: 12/16/2022] Open
Abstract
Dietary fats may exert selective pressures on Lactobacillus species, however, knowledge on the mechanisms of adaptation to fat stress in these organisms is still fragmentary. This study was undertaken to gain insight into the mechanisms of adaptation of Lactobacillus plantarum WCFS1 to olive oil challenge by whole genome transcriptional profiling using DNA microarrays. A set of 230 genes were differentially expressed by L. plantarum WCFS1 to respond to this vegetable oil. This response involved elements typical of the stringent response, as indicated by the induction of genes involved in stress-related pathways and downregulation of genes related to processes associated with rapid growth. A set of genes involved in the transport and metabolism of compatible solutes were downregulated, indicating that this organism does not require osmoprotective mechanisms in presence of olive oil. The fatty acid biosynthetic pathway was thoroughly downregulated at the transcriptional level, which coincided with a diminished expression of genes controlled by this pathway in other organisms and that are required for the respiratory function, pyruvate dehydrogenase activity, RNA processing and cell size setting. Finally, a set of genes involved in host-cell signaling by L. plantarum were differentially regulated indicating that olive oil can influence the expression of metabolic traits involved in the crosstalk between this bacterium and the host.
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Affiliation(s)
| | | | | | | | | | - Félix López de Felipe
- Laboratorio de Biotecnología Bacteriana, Instituto de Ciencia y Tecnología de los Alimentos y Nutrición – Consejo Superior de Investigaciones CientificasMadrid, Spain
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29
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Tardu M, Bulut S, Kavakli IH. MerR and ChrR mediate blue light induced photo-oxidative stress response at the transcriptional level in Vibrio cholerae. Sci Rep 2017; 7:40817. [PMID: 28098242 PMCID: PMC5241685 DOI: 10.1038/srep40817] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/09/2016] [Indexed: 12/14/2022] Open
Abstract
Blue light (BL) is a major environmental factor that affects the physiology, behavior, and infectivity of bacteria as it contributes to the generation of reactive oxygen species (ROS) while increasing photo-oxidative stress in cells. However, precise photo-oxidative response mechanism in non-phototrophic bacteria is yet to be elucidated. In this study, we investigated the effect of BL in Vibrio cholerae by using genetics and transcriptome profiling. Genome-wide analysis revealed that transcription of 6.3% of V. cholerae genes were regulated by BL. We further showed that BL enhances ROS production, which is generated through the oxidative phosphorylation. To understand signaling mechanisms, we generated several knockouts and analyzed their transcriptome under BL exposure. Studies with a double-knockout confirm an anti-sigma factor (ChrR) and putative metalloregulatory-like protein (MerR) are responsible for the genome-wide regulation to BL response in V. cholerae. Collectively, these results demonstrate that MerR-like proteins, in addition to ChrR, are required for V. cholerae to mount an appropriate response against photo-oxidative stress induced by BL. Outside its natural host, V. cholerae can survive for extended periods in natural aquatic environments. Therefore, the regulation of light response for V. cholerae may be a critical cellular process for its survival in these environments.
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Affiliation(s)
- Mehmet Tardu
- Computational Science and Engineering, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, Turkey
| | - Selma Bulut
- Chemical and Biological Engineering, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, Turkey
| | - Ibrahim Halil Kavakli
- Computational Science and Engineering, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, Turkey.,Chemical and Biological Engineering, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, Turkey.,Molecular Biology and Genetics, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, Turkey
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30
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Davis MC, Kesthely CA, Franklin EA, MacLellan SR. The essential activities of the bacterial sigma factor. Can J Microbiol 2016; 63:89-99. [PMID: 28117604 DOI: 10.1139/cjm-2016-0576] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Transcription is the first and most heavily regulated step in gene expression. Sigma (σ) factors are general transcription factors that reversibly bind RNA polymerase (RNAP) and mediate transcription of all genes in bacteria. σ Factors play 3 major roles in the RNA synthesis initiation process: they (i) target RNAP holoenzyme to specific promoters, (ii) melt a region of double-stranded promoter DNA and stabilize it as a single-stranded open complex, and (iii) interact with other DNA-binding transcription factors to contribute complexity to gene expression regulation schemes. Recent structural studies have demonstrated that when σ factors bind promoter DNA, they capture 1 or more nucleotides that are flipped out of the helical DNA stack and this stabilizes the promoter open-complex intermediate that is required for the initiation of RNA synthesis. This review describes the structure and function of the σ70 family of σ proteins and the essential roles they play in the transcription process.
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Affiliation(s)
- Maria C Davis
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.,Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Christopher A Kesthely
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.,Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Emily A Franklin
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.,Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Shawn R MacLellan
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.,Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
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31
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Hu Y, Wang Z, Feng L, Chen Z, Mao C, Zhu Y, Chen S. σ(E) -dependent activation of RbpA controls transcription of the furA-katG operon in response to oxidative stress in mycobacteria. Mol Microbiol 2016; 102:107-20. [PMID: 27353316 DOI: 10.1111/mmi.13449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2016] [Indexed: 01/08/2023]
Abstract
Mycobacterium tuberculosis adopts various strategies to cope with oxidative stress during infection. Transcriptional regulators, including σ factors, make important contributions to this stress response, but how these proteins cooperate with each other is largely unknown. In this study, the role of RbpA and its cooperation with σ factors in response to oxidative stress are investigated. Knock down expression of rbpA in Mycobacterium smegmatis attenuated bacterial survival in the presence of H2 O2 . Additionally, transcription of the rbpA gene was induced by H2 O2 in a σ(E) -dependent manner. After induction, RbpA interacts with the principal sigma factor, σ(A) , to control the transcription of furA-katG operon, which encodes an H2 O2 scavenging enzyme. Moreover, this regulation is responsible for the role of σ(E) in oxidative response because bacterial survival was attenuated and transcription of the furA-katG operon was down-regulated with H2 O2 treatment in sigE deletion mutant (ΔsigE), and over-expression of RbpA in ΔsigE strain restored all of these phenotypes. Taken together, our study first illustrated a mechanism for σ(E) in response to oxidative stress through regulation of rbpA transcription. This study was also the first to demonstrate that RbpA is required for the full response to oxidative stress by cooperating with the principal σ(A) .
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Affiliation(s)
- Yangbo Hu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Zhongwei Wang
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, 10086, China
| | - Lipeng Feng
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, 10086, China
| | - Zhenkang Chen
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, 10086, China
| | - Chunyou Mao
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, 10086, China
| | - Yan Zhu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, 10086, China
| | - Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
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OsdR of Streptomyces coelicolor and the Dormancy Regulator DevR of Mycobacterium tuberculosis Control Overlapping Regulons. mSystems 2016; 1:mSystems00014-16. [PMID: 27822533 PMCID: PMC5069765 DOI: 10.1128/msystems.00014-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/29/2016] [Indexed: 11/20/2022] Open
Abstract
Dormancy is a state of growth cessation that allows bacteria to escape the host defense system and antibiotic challenge. Understanding the mechanisms that control dormancy is of key importance for the treatment of latent infections, such as those from Mycobacterium tuberculosis. In mycobacteria, dormancy is controlled by the response regulator DevR, which responds to conditions of hypoxia. Here, we show that OsdR of Streptomyces coelicolor recognizes the same regulatory element and controls a regulon that consists of genes involved in the control of stress and development. Only the core regulon in the direct vicinity of dosR and osdR is conserved between M. tuberculosis and S. coelicolor, respectively. Thus, we show how the system has diverged from allowing escape from the host defense system by mycobacteria to the control of sporulation by complex multicellular streptomycetes. This provides novel insights into how bacterial growth and development are coordinated with the environmental conditions. Two-component regulatory systems allow bacteria to respond adequately to changes in their environment. In response to a given stimulus, a sensory kinase activates its cognate response regulator via reversible phosphorylation. The response regulator DevR activates a state of dormancy under hypoxia in Mycobacterium tuberculosis, allowing this pathogen to escape the host defense system. Here, we show that OsdR (SCO0204) of the soil bacterium Streptomyces coelicolor is a functional orthologue of DevR. OsdR, when activated by the sensory kinase OsdK (SCO0203), binds upstream of the DevR-controlled dormancy genes devR, hspX, and Rv3134c of M. tuberculosis. In silico analysis of the S. coelicolor genome combined with in vitro DNA binding studies identified many binding sites in the genomic region around osdR itself and upstream of stress-related genes. This binding correlated well with transcriptomic responses, with deregulation of developmental genes and genes related to stress and hypoxia in the osdR mutant. A peak in osdR transcription in the wild-type strain at the onset of aerial growth correlated with major changes in global gene expression. Taken together, our data reveal the existence of a dormancy-related regulon in streptomycetes which plays an important role in the transcriptional control of stress- and development-related genes. IMPORTANCE Dormancy is a state of growth cessation that allows bacteria to escape the host defense system and antibiotic challenge. Understanding the mechanisms that control dormancy is of key importance for the treatment of latent infections, such as those from Mycobacterium tuberculosis. In mycobacteria, dormancy is controlled by the response regulator DevR, which responds to conditions of hypoxia. Here, we show that OsdR of Streptomyces coelicolor recognizes the same regulatory element and controls a regulon that consists of genes involved in the control of stress and development. Only the core regulon in the direct vicinity of dosR and osdR is conserved between M. tuberculosis and S. coelicolor, respectively. Thus, we show how the system has diverged from allowing escape from the host defense system by mycobacteria to the control of sporulation by complex multicellular streptomycetes. This provides novel insights into how bacterial growth and development are coordinated with the environmental conditions.
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33
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Mycobacterium tuberculosis Transcription Machinery: Ready To Respond to Host Attacks. J Bacteriol 2016; 198:1360-73. [PMID: 26883824 DOI: 10.1128/jb.00935-15] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Regulating responses to stress is critical for all bacteria, whether they are environmental, commensal, or pathogenic species. For pathogenic bacteria, successful colonization and survival in the host are dependent on adaptation to diverse conditions imposed by the host tissue architecture and the immune response. Once the bacterium senses a hostile environment, it must enact a change in physiology that contributes to the organism's survival strategy. Inappropriate responses have consequences; hence, the execution of the appropriate response is essential for survival of the bacterium in its niche. Stress responses are most often regulated at the level of gene expression and, more specifically, transcription. This minireview focuses on mechanisms of regulating transcription initiation that are required by Mycobacterium tuberculosis to respond to the arsenal of defenses imposed by the host during infection. In particular, we highlight how certain features of M. tuberculosis physiology allow this pathogen to respond swiftly and effectively to host defenses. By enacting highly integrated and coordinated gene expression changes in response to stress,M. tuberculosis is prepared for battle against the host defense and able to persist within the human population.
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Sharp JD, Singh AK, Park ST, Lyubetskaya A, Peterson MW, Gomes ALC, Potluri LP, Raman S, Galagan JE, Husson RN. Comprehensive Definition of the SigH Regulon of Mycobacterium tuberculosis Reveals Transcriptional Control of Diverse Stress Responses. PLoS One 2016; 11:e0152145. [PMID: 27003599 PMCID: PMC4803200 DOI: 10.1371/journal.pone.0152145] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/09/2016] [Indexed: 11/24/2022] Open
Abstract
Expression of SigH, one of 12 Mycobacterium tuberculosis alternative sigma factors, is induced by heat, oxidative and nitric oxide stresses. SigH activation has been shown to increase expression of several genes, including genes involved in maintaining redox equilibrium and in protein degradation. However, few of these are known to be directly regulated by SigH. The goal of this project is to comprehensively define the Mycobacterium tuberculosis genes and operons that are directly controlled by SigH in order to gain insight into the role of SigH in regulating M. tuberculosis physiology. We used ChIP-Seq to identify in vivo SigH binding sites throughout the M. tuberculosis genome, followed by quantification of SigH-dependent expression of genes linked to these sites and identification of SigH-regulated promoters. We identified 69 SigH binding sites, which are located both in intergenic regions and within annotated coding sequences in the annotated M. tuberculosis genome. 41 binding sites were linked to genes that showed greater expression following heat stress in a SigH-dependent manner. We identified several genes not previously known to be regulated by SigH, including genes involved in DNA repair, cysteine biosynthesis, translation, and genes of unknown function. Experimental and computational analysis of SigH-regulated promoter sequences within these binding sites identified strong consensus -35 and -10 promoter sequences, but with tolerance for non-consensus bases at specific positions. This comprehensive identification and validation of SigH-regulated genes demonstrates an extended SigH regulon that controls an unexpectedly broad range of stress response functions.
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Affiliation(s)
- Jared D. Sharp
- Division of Infectious Diseases, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States of America
| | - Atul K. Singh
- Division of Infectious Diseases, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States of America
| | - Sang Tae Park
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts 02118, United States of America
| | - Anna Lyubetskaya
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, United States of America
| | - Matthew W. Peterson
- Department of Microbiology, Boston University, Boston, Massachusetts 02215, United States of America
| | - Antonio L. C. Gomes
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, United States of America
| | - Lakshmi-Prasad Potluri
- Division of Infectious Diseases, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States of America
| | - Sahadevan Raman
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts 02118, United States of America
| | - James E. Galagan
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts 02118, United States of America
- Bioinformatics Program, Boston University, Boston, Massachusetts 02215, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, United States of America
- Department of Microbiology, Boston University, Boston, Massachusetts 02215, United States of America
| | - Robert N. Husson
- Division of Infectious Diseases, Boston Children’s Hospital and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States of America
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Hillion M, Antelmann H. Thiol-based redox switches in prokaryotes. Biol Chem 2016; 396:415-44. [PMID: 25720121 DOI: 10.1515/hsz-2015-0102] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/05/2015] [Indexed: 12/12/2022]
Abstract
Bacteria encounter reactive oxygen species (ROS) as a consequence of the aerobic life or as an oxidative burst of activated neutrophils during infections. In addition, bacteria are exposed to other redox-active compounds, including hypochloric acid (HOCl) and reactive electrophilic species (RES) such as quinones and aldehydes. These reactive species often target the thiol groups of cysteines in proteins and lead to thiol-disulfide switches in redox-sensing regulators to activate specific detoxification pathways and to restore the redox balance. Here, we review bacterial thiol-based redox sensors that specifically sense ROS, RES and HOCl via thiol-based mechanisms and regulate gene transcription in Gram-positive model bacteria and in human pathogens, such as Staphylococcus aureus and Mycobacterium tuberculosis. We also pay particular attention to emerging widely conserved HOCl-specific redox regulators that have been recently characterized in Escherichia coli. Different mechanisms are used to sense and respond to ROS, RES and HOCl by 1-Cys-type and 2-Cys-type thiol-based redox sensors that include versatile thiol-disulfide switches (OxyR, OhrR, HypR, YodB, NemR, RclR, Spx, RsrA/RshA) or alternative Cys phosphorylations (SarZ, MgrA, SarA), thiol-S-alkylation (QsrR), His-oxidation (PerR) and methionine oxidation (HypT). In pathogenic bacteria, these redox-sensing regulators are often important virulence regulators and required for adapation to the host immune defense.
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Liu X, Sun M, Cheng Y, Yang R, Wen Y, Chen Z, Li J. OxyR is a key regulator in response to oxidative stress in Streptomyces avermitilis. MICROBIOLOGY-SGM 2016; 162:707-716. [PMID: 26839064 DOI: 10.1099/mic.0.000251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The role of the H2O2-sensing transcriptional regulator OxyR in oxidative stress responses in Streptomyces avermitilis was investigated. An oxyR deletion mutant was more sensitive to H2O2 and tert-butyl hydroperoxide than was the WT strain, indicating that OxyR mediates the defensive system against H2O2 and organic peroxide. Evidence presented herein suggests that in cells treated with exogenous H2O2, the oxidized form of OxyR activated expression of ahpCD by binding to a palindromic sequence of the promoter region. Oxidized OxyR also induced expression of other antioxidant enzymes (KatA1, KatA2, KatA3 and OhrB1) and oxidative stress regulators (CatR, OhrR and σR). The thiol-oxidative stress regulator gene sigR was regulated at the transcription level by OxyR. We conclude that OxyR is necessary to activate transcription of sigR from the σR-dependent promoter to express an unstable larger isoform of σR during oxidative stress. In response to oxidative stress, OxyR facilitates rapid production of H2O2-scavenging enzymes to repair oxidative damage through direct regulation and cascaded regulation of CatR, OhrR and σR.
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Affiliation(s)
- Xingchao Liu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Meng Sun
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Yaqing Cheng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Renjun Yang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Ying Wen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Zhi Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
| | - Jilun Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China
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In Streptomyces coelicolor SigR, methionine at the -35 element interacting region 4 confers the -31'-adenine base selectivity. Biochem Biophys Res Commun 2016; 470:257-262. [PMID: 26775842 DOI: 10.1016/j.bbrc.2016.01.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/12/2016] [Indexed: 11/20/2022]
Abstract
In Gram-positive Streptomyces coelicolor A3(2), SigR (Sc σ(R)) of the group IV ECF sigma factor singly activates expression of more than 30 oxidation responsive genes. Of the two promoter-binding domains--individually called region 2 and region 4 - within Sc σ(R), we hereby report a 2.6 Å resolution structure of the -35 element interacting carboxyl-terminal region 4 (Sc σ(R)4). Structural comparison of Sc σ(R)4 with the Escherichia coli SigE (Ec σ(E)) in complex with Ec σ(E) -35 element suggested that a single residue (Sc σ(R) Met188 and Ec σ(E) Arg171) may be responsible for distinguishing the one-base pair difference of the -35 elements--Sc σ(R)(-31')ATTCC(-35') ((-31')A) vs. Ec σ(E)(-31')GTTCC(-35') ((-31')G)--by interacting with the -31'-base. Further studies using expressed Sc σ(R) indicate that the wild-type Sc σ(R) with Met188 selectively interacted with the (-31')A sequence over the (-31')G sequence, whereas a mutation of Met188 to arginine resulted in interaction with both (-31')A and (-31')G sequences. Hence, we conclude that Met188 of Sc σ(R) confers the (-31')A-selectivity in -35 element interaction by disfavoured interaction with the (-31')G base.
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Myronovskyi M, Luzhetskyy A. Native and engineered promoters in natural product discovery. Nat Prod Rep 2016; 33:1006-19. [DOI: 10.1039/c6np00002a] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transcriptional activation of biosynthetic gene clusters.
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Affiliation(s)
- Maksym Myronovskyi
- Helmholtz-Institute for Pharmaceutical Research Saarland
- 66123 Saarbrücken
- Germany
| | - Andriy Luzhetskyy
- Helmholtz-Institute for Pharmaceutical Research Saarland
- 66123 Saarbrücken
- Germany
- Department of Pharmaceutical Biotechnology
- Saarland University
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Li X, Wang J, Li S, Ji J, Wang W, Yang K. ScbR- and ScbR2-mediated signal transduction networks coordinate complex physiological responses in Streptomyces coelicolor. Sci Rep 2015; 5:14831. [PMID: 26442964 PMCID: PMC4595836 DOI: 10.1038/srep14831] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/07/2015] [Indexed: 12/21/2022] Open
Abstract
In model organism Streptomyces coelicolor, γ-butyrolactones (GBLs) and antibiotics were recognized as signalling molecules playing fundamental roles in intra- and interspecies communications. To dissect the GBL and antibiotic signalling networks systematically, the in vivo targets of their respective receptors ScbR and ScbR2 were identified on a genome scale by ChIP-seq. These identified targets encompass many that are known to play important roles in diverse cellular processes (e.g. gap1, pyk2, afsK, nagE2, cdaR, cprA, cprB, absA1, actII-orf4, redZ, atrA, rpsL and sigR), and they formed regulatory cascades, sub-networks and feedforward loops to elaborately control key metabolite processes, including primary and secondary metabolism, morphological differentiation and stress response. Moreover, interplay among ScbR, ScbR2 and other regulators revealed intricate cross talks between signalling pathways triggered by GBLs, antibiotics, nutrient availability and stress. Our work provides a global view on the specific responses that could be triggered by GBL and antibiotic signals in S. coelicolor, among which the main echo was the change of production profile of endogenous antibiotics and antibiotic signals manifested a role to enhance bacterial stress tolerance as well, shedding new light on GBL and antibiotic signalling networks widespread among streptomycetes.
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Affiliation(s)
- Xiao Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Juan Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Shanshan Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Junjie Ji
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Weishan Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Keqian Yang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
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Abstract
Bacteria live in a toxic world in which their competitors excrete hydrogen peroxide or superoxide-generating redox-cycling compounds. They protect themselves by activating regulons controlled by the OxyR, PerR, and SoxR transcription factors. OxyR and PerR sense peroxide when it oxidizes key thiolate or iron moieties, respectively; they then induce overlapping sets of proteins that defend their vulnerable metalloenzymes. An additional role for OxyR in detecting electrophilic compounds is possible. In some nonenteric bacteria, SoxR appears to control the synthesis and export of redox-cycling compounds, whereas in the enteric bacteria it defends the cell against the same agents. When these compounds oxidize its iron-sulfur cluster, SoxR induces proteins that exclude, excrete, or modify them. It also induces enzymes that defend the cell against the superoxide that such compounds make. Recent work has brought new insight into the biochemistry and physiology of these responses, and comparative studies have clarified their evolutionary histories.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, Urbana, Illinois 61801;
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41
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Kim JN, Jeong Y, Yoo JS, Roe JH, Cho BK, Kim BG. Genome-scale analysis reveals a role for NdgR in the thiol oxidative stress response in Streptomyces coelicolor. BMC Genomics 2015; 16:116. [PMID: 25766138 PMCID: PMC4340878 DOI: 10.1186/s12864-015-1311-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND NdgR is an IclR-type transcription factor that regulates leucine biosynthesis and other metabolic pathways in Streptomyces coelicolor. Recent study revealed that NdgR is one of the regulatory targets of SigR, an oxidative stress response sigma factor, suggesting that the NdgR plays an important physiological role in response to environmental stresses. Although the regulatory functions of NdgR were partly characterized, determination of its regulon is required for better understanding of the transcriptional regulatory network related with the oxidative stress response. RESULTS We determined genome-wide binding loci of NdgR by using chromatin immunoprecipitation coupled with sequencing (ChIP-seq) and explored its physiological roles. The ChIP-seq profiles revealed 19 direct binding loci with a 15-bp imperfect palindromic motif, including 34 genes in their transcription units. Most genes in branched-chain amino acid and cysteine biosynthesis pathways were involved in the NdgR regulon. We proved that ndgR is induced by SigR under the thiol oxidation, and that an ndgR mutant strain is sensitive to the thiol oxidizing agent, diamide. Through the expression test of NdgR and the target genes for NdgR under diamide treatment, regulatory motifs were suggested. Interestingly, NdgR constitutes two regulatory motifs, coherent and incoherent feed-forward loops (FFL), in order to control its regulon under the diamide treatment. Using the regulatory motifs, NdgR regulates cysteine biosynthesis in response to thiol oxidative stress, enabling cells to maintain sulfur assimilation with homeostasis under stress conditions. CONCLUSIONS Our analysis revealed that NdgR is a global transcriptional regulator involved in the regulation of branched-chain amino acids biosynthesis and sulphur assimilation. The identification of the NdgR regulon broadens our knowledge regarding complex regulatory networks governing amino acid biosynthesis in the context of stress responses in S. coelicolor.
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Affiliation(s)
- Ji-Nu Kim
- School of Chemical and Biological Engineering, Institute of Molecular Biology and Genetics, and Bioengineering Institute, Seoul National University, Seoul, Korea.
| | - Yujin Jeong
- Department of Biological Sciences and KAIST institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
| | - Ji Sun Yoo
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 151-742, Korea.
| | - Jung-Hye Roe
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 151-742, Korea.
| | - Byung-Kwan Cho
- Department of Biological Sciences and KAIST institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea.
| | - Byung-Gee Kim
- School of Chemical and Biological Engineering, Institute of Molecular Biology and Genetics, and Bioengineering Institute, Seoul National University, Seoul, Korea.
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Hnilicová J, Jirát Matějčková J, Šiková M, Pospíšil J, Halada P, Pánek J, Krásný L. Ms1, a novel sRNA interacting with the RNA polymerase core in mycobacteria. Nucleic Acids Res 2014; 42:11763-76. [PMID: 25217589 PMCID: PMC4191392 DOI: 10.1093/nar/gku793] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/19/2014] [Accepted: 08/20/2014] [Indexed: 11/12/2022] Open
Abstract
Small RNAs (sRNAs) are molecules essential for a number of regulatory processes in the bacterial cell. Here we characterize Ms1, a sRNA that is highly expressed in Mycobacterium smegmatis during stationary phase of growth. By glycerol gradient ultracentrifugation, RNA binding assay, and RNA co-immunoprecipitation, we show that Ms1 interacts with the RNA polymerase (RNAP) core that is free of the primary sigma factor (σA) or any other σ factor. This contrasts with the situation in most other species where it is 6S RNA that interacts with RNAP and this interaction requires the presence of σA. The difference in the interaction of the two types of sRNAs (Ms1 or 6S RNA) with RNAP possibly reflects the difference in the composition of the transcriptional machinery between mycobacteria and other species. Unlike Escherichia coli, stationary phase M. smegmatis cells contain relatively few RNAP molecules in complex with σA. Thus, Ms1 represents a novel type of small RNAs interacting with RNAP.
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Affiliation(s)
- Jarmila Hnilicová
- Department of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Jitka Jirát Matějčková
- Department of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Michaela Šiková
- Department of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Jiří Pospíšil
- Department of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Petr Halada
- Department of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Josef Pánek
- Department of Bioinformatics, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
| | - Libor Krásný
- Department of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic
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Hu Y, Morichaud Z, Perumal AS, Roquet-Baneres F, Brodolin K. Mycobacterium RbpA cooperates with the stress-response σB subunit of RNA polymerase in promoter DNA unwinding. Nucleic Acids Res 2014; 42:10399-408. [PMID: 25122744 PMCID: PMC4176334 DOI: 10.1093/nar/gku742] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
RbpA, a transcriptional activator that is essential for Mycobacterium tuberculosis replication and survival during antibiotic treatment, binds to RNA polymerase (RNAP) in the absence of promoter DNA. It has been hypothesized that RbpA stimulates housekeeping gene expression by promoting assembly of the σA subunit with core RNAP. Here, using a purified in vitro transcription system of M. tuberculosis, we show that RbpA functions in a promoter-dependent manner as a companion of RNAP essential for promoter DNA unwinding and formation of the catalytically active open promoter complex (RPo). Screening for RbpA activity using a full panel of the M. tuberculosis σ subunits demonstrated that RbpA targets σA and stress-response σB, but not the alternative σ subunits from the groups 3 and 4. In contrast to σA, the σB subunit activity displayed stringent dependency upon RbpA. These results suggest that RbpA-dependent control of RPo formation provides a mechanism for tuning gene expression during the switch between different physiological states, and in the stress response.
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Affiliation(s)
- Yangbo Hu
- CNRS UMR 5236 - UM1 - UM2, Centre d'études d'agents Pathogénes et Biothechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Zakia Morichaud
- CNRS UMR 5236 - UM1 - UM2, Centre d'études d'agents Pathogénes et Biothechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Ayyappasamy Sudalaiyadum Perumal
- CNRS UMR 5236 - UM1 - UM2, Centre d'études d'agents Pathogénes et Biothechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Françoise Roquet-Baneres
- CNRS UMR 5236 - UM1 - UM2, Centre d'études d'agents Pathogénes et Biothechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Konstantin Brodolin
- CNRS UMR 5236 - UM1 - UM2, Centre d'études d'agents Pathogénes et Biothechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
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Sigma S-dependent antioxidant defense protects stationary-phase Escherichia coli against the bactericidal antibiotic gentamicin. Antimicrob Agents Chemother 2014; 58:5964-75. [PMID: 25070093 DOI: 10.1128/aac.03683-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Stationary-phase bacteria are important in disease. The σ(s)-regulated general stress response helps them become resistant to disinfectants, but the role of σ(s) in bacterial antibiotic resistance has not been elucidated. Loss of σ(s) rendered stationary-phase Escherichia coli more sensitive to the bactericidal antibiotic gentamicin (Gm), and proteomic analysis suggested involvement of a weakened antioxidant defense. Use of the psfiA genetic reporter, 3'-(p-hydroxyphenyl) fluorescein (HPF) dye, and Amplex Red showed that Gm generated more reactive oxygen species (ROS) in the mutant. HPF measurements can be distorted by cell elongation, but Gm did not affect stationary-phase cell dimensions. Coadministration of the antioxidant N-acetyl cysteine (NAC) decreased drug lethality particularly in the mutant, as did Gm treatment under anaerobic conditions that prevent ROS formation. Greater oxidative stress, due to insufficient quenching of endogenous ROS and/or respiration-linked electron leakage, therefore contributed to the greater sensitivity of the mutant; infection by a uropathogenic strain in mice showed this to be the case also in vivo. Disruption of antioxidant defense by eliminating the quencher proteins, SodA/SodB and KatE/SodA, or the pentose phosphate pathway proteins, Zwf/Gnd and TalA, which provide NADPH for ROS decomposition, also generated greater oxidative stress and killing by Gm. Thus, besides its established mode of action, Gm also kills stationary-phase bacteria by generating oxidative stress, and targeting the antioxidant defense of E. coli can enhance its efficacy. Relevant aspects of the current controversy on the role of ROS in killing by bactericidal drugs of exponential-phase bacteria, which represent a different physiological state, are discussed.
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Verma AK, Chatterji D. Dual role of MsRbpA: transcription activation and rescue of transcription from the inhibitory effect of rifampicin. MICROBIOLOGY-SGM 2014; 160:2018-2029. [PMID: 24987104 DOI: 10.1099/mic.0.079186-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
MsRbpA is an RNA polymerase (RNAP) binding protein from Mycobacterium smegmatis. According to previous studies, MsRbpA rescues rifampicin-induced transcription inhibition upon binding to the RNAP. Others have shown that RbpA from Mycobacterium tuberculosis (MtbRbpA) is a transcription activator. In this study, we report that both MsRbpA and MtbRbpA activate transcription as well as rescue rifampicin-induced transcription inhibition. Transcription activation is achieved through the increased formation of closed RNAP-promoter complex as well as enhanced rate of conversion of this complex to a stable transcriptionally competent RNAP-promoter complex. When a 16 aa peptide fragment (Asp 58 to Lys 73) was deleted from MsRbpA, the resulting protein showed 1000-fold reduced binding with core RNAP. The deletion results in abolition of transcription activation and rescue of transcription from the inhibitory effect of rifampicin. Through alanine scanning of this essential region of MsRbpA, Gly 67, Val 69, Pro 70 and Pro 72 residues are identified to be important for MsRbpA function. Furthermore, we report here that the protein is indispensable for M. smegmatis, and it appears to help the organism grow in the presence of the antibiotic rifampicin.
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Affiliation(s)
- Amit Kumar Verma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka-560012, India
| | - Dipankar Chatterji
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka-560012, India
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Chandra G, Chater KF. Developmental biology of Streptomyces from the perspective of 100 actinobacterial genome sequences. FEMS Microbiol Rev 2014; 38:345-79. [PMID: 24164321 PMCID: PMC4255298 DOI: 10.1111/1574-6976.12047] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 08/06/2013] [Accepted: 08/20/2013] [Indexed: 12/22/2022] Open
Abstract
To illuminate the evolution and mechanisms of actinobacterial complexity, we evaluate the distribution and origins of known Streptomyces developmental genes and the developmental significance of actinobacteria-specific genes. As an aid, we developed the Actinoblast database of reciprocal blastp best hits between the Streptomyces coelicolor genome and more than 100 other actinobacterial genomes (http://streptomyces.org.uk/actinoblast/). We suggest that the emergence of morphological complexity was underpinned by special features of early actinobacteria, such as polar growth and the coupled participation of regulatory Wbl proteins and the redox-protecting thiol mycothiol in transducing a transient nitric oxide signal generated during physiologically stressful growth transitions. It seems that some cell growth and division proteins of early actinobacteria have acquired greater importance for sporulation of complex actinobacteria than for mycelial growth, in which septa are infrequent and not associated with complete cell separation. The acquisition of extracellular proteins with structural roles, a highly regulated extracellular protease cascade, and additional regulatory genes allowed early actinobacterial stationary phase processes to be redeployed in the emergence of aerial hyphae from mycelial mats and in the formation of spore chains. These extracellular proteins may have contributed to speciation. Simpler members of morphologically diverse clades have lost some developmental genes.
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Wei ZH, Chen H, Zhang C, Ye BC. FRET-based system for probing protein-protein interactions between σR and RsrA from Streptomyces coelicolor in response to the redox environment. PLoS One 2014; 9:e92330. [PMID: 24651617 PMCID: PMC3961337 DOI: 10.1371/journal.pone.0092330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 02/21/2014] [Indexed: 11/26/2022] Open
Abstract
Protein-protein interactions between sigma factor σ(R) and its corresponding zinc-binding anti-sigma (ZAS) protein RsrA trigger the thioredoxin system for maintaining cellular redox homeostasis in S. coelicolor. RsrA bound to zinc associates with σ(R), inhibiting its transcriptional activity in a reducing environment. During disulfide stress it forms intramolecular disulfide bonds, leading to zinc release and dissociation from σ(R), which initiates transcription to produce reductase and thioredoxin. We designed a fluorescence resonance energy transfer (FRET) based system for monitoring protein-protein interactions between σ(R) and RsrA to further understand how this redox switch regulates the thioredoxin system in S. coelicolor in response to its redox environment, especially various reactive oxygen species (ROS) derived from different metabolic pathways, and clarify the different response mechanisms between Zn-RsrA and apo-RsrA. By the use of the FRET approach described here, we showed that zinc protected thiols in RsrA and causes the σ(R)-RsrA complex to form a more compact structure. This system was also utilized to detect changes in redox status induced by ROS and diamide in real time in E. coli cells.
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Affiliation(s)
- Zi-Han Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Huan Chen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Chang Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Bang-Ce Ye
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
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Ternan NG, Jain S, Graham RLJ, McMullan G. Semiquantitative analysis of clinical heat stress in Clostridium difficile strain 630 using a GeLC/MS workflow with emPAI quantitation. PLoS One 2014; 9:e88960. [PMID: 24586458 PMCID: PMC3933415 DOI: 10.1371/journal.pone.0088960] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 01/16/2014] [Indexed: 12/11/2022] Open
Abstract
Clostridium difficile is considered to be the most frequent cause of infectious bacterial diarrhoea in hospitals worldwide yet its adaptive ability remains relatively uncharacterised. Here, we used GeLC/MS and the exponentially modified protein abundance index (emPAI) calculation to determine proteomic changes in response to a clinically relevant heat stress. Reproducibility between both biological and technical replicates was good, and a 37°C proteome of 224 proteins was complemented by a 41°C proteome of 202 proteins at a 1% false discovery rate. Overall, 236 C. difficile proteins were identified and functionally categorised, of which 178 were available for comparative purposes. A total of 65 proteins (37%) were modulated by 1.5-fold or more at 41°C compared to 37°C and we noted changes in the majority of proteins associated with amino acid metabolism, including upregulation of the reductive branch of the leucine fermentation pathway. Motility was reduced at 41°C as evidenced by a 2.7 fold decrease in the flagellar filament protein, FliC, and a global increase in proteins associated with detoxification and adaptation to atypical conditions was observed, concomitant with decreases in proteins mediating transcriptional elongation and the initiation of protein synthesis. Trigger factor was down regulated by almost 5-fold. We propose that under heat stress, titration of the GroESL and dnaJK/grpE chaperones by misfolded proteins will, in the absence of trigger factor, prevent nascent chains from emerging efficiently from the ribosome causing translational stalling and also an increase in secretion. The current work has thus allowed development of a heat stress model for the key cellular processes of protein folding and export.
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Affiliation(s)
- Nigel G. Ternan
- Northern Ireland Centre for Food and Health (NICHE), School of Biomedical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, United Kingdom
- * E-mail:
| | - Shailesh Jain
- Northern Ireland Centre for Food and Health (NICHE), School of Biomedical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, United Kingdom
| | - Robert L. J. Graham
- School of Medicine, University of Manchester, Manchester, Greater Manchester, United Kingdom
| | - Geoff McMullan
- Northern Ireland Centre for Food and Health (NICHE), School of Biomedical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, United Kingdom
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Yagüe P, Rodríguez-García A, López-García MT, Rioseras B, Martín JF, Sánchez J, Manteca A. Transcriptomic analysis of liquid non-sporulating Streptomyces coelicolor cultures demonstrates the existence of a complex differentiation comparable to that occurring in solid sporulating cultures. PLoS One 2014; 9:e86296. [PMID: 24466012 PMCID: PMC3897704 DOI: 10.1371/journal.pone.0086296] [Citation(s) in RCA: 31] [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: 10/21/2013] [Accepted: 12/12/2013] [Indexed: 11/18/2022] Open
Abstract
Streptomyces species produce many clinically relevant secondary metabolites and exhibit a complex development that includes hyphal differentiation and sporulation in solid cultures. Industrial fermentations are usually performed in liquid cultures, conditions in which Streptomyces strains generally do not sporulate, and it was traditionally assumed that no differentiation took place. The aim of this work was to compare the transcriptomes of S. coelicolor growing in liquid and solid cultures, deepening the knowledge of Streptomyces differentiation. Microarrays demonstrated that gene expression in liquid and solid cultures were comparable and data indicated that physiological differentiation was similar for both conditions. Eighty-six percent of all transcripts showed similar abundances in liquid and solid cultures, such as those involved in the biosynthesis of actinorhodin (actVA, actII-4) and undecylprodigiosin (redF); activation of secondary metabolism (absR1, ndsA); genes regulating hydrophobic cover formation (aerial mycelium) (bldB, bldC, bldM, bldN, sapA, chpC, chpD, chpE, chpH, ramA, ramC, ramS); and even some genes regulating early stages of sporulation (wblA, whiG, whiH, whiJ). The two most important differences between transcriptomes from liquid and solid cultures were: first, genes related to secondary metabolite biosynthesis (CDA, CPK, coelichelin, desferrioxamine clusters) were highly up-regulated in liquid but not in solid cultures; and second, genes involved in the final stages of hydrophobic cover/spore maturation (chpF, rdlA, whiE, sfr) were up-regulated in solid but not in liquid cultures. New information was also provided for several non-characterized genes differentially expressed in liquid and solid cultures which might be regulating, at least in part, the metabolic and developmental differences observed between liquid and solid cultures.
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Affiliation(s)
- Paula Yagüe
- Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | | | - María Teresa López-García
- Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Beatriz Rioseras
- Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Juan Francisco Martín
- Instituto de Biotecnología de León, INBIOTEC, Parque Científico de León, León, Spain
| | - Jesús Sánchez
- Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
| | - Angel Manteca
- Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, Oviedo, Spain
- * E-mail:
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Gupta N, Gupta A, Kumar S, Mishra R, Singh C, Tripathi AK. Cross-talk between cognate and noncognate RpoE sigma factors and Zn(2+)-binding anti-sigma factors regulates photooxidative stress response in Azospirillum brasilense. Antioxid Redox Signal 2014; 20:42-59. [PMID: 23725220 DOI: 10.1089/ars.2013.5314] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Azospirillum brasilense harbors two redox-sensitive Zinc-binding anti-sigma (ZAS) factors (ChrR1 and ChrR2), which negatively regulate the activity of their cognate extra-cytoplasmic function (ECF) σ factors (RpoE1 and RpoE2) by occluding their binding to the core enzyme. Both pairs of RpoE-ChrR control responses to photooxidative stress. The aim of this study was to investigate whether the two RpoE-ChrR pairs cross-talk while responding to the stress. RESULTS In silico analysis showed a high sequence similarity between ChrR1 and ChrR2 proteins, but differences in redox sensitivity. Using in silico and in vitro methods of protein-protein interaction, we have shown that both ChrR1 and ChrR2 proteins physically bind to their noncognate RpoE proteins. Restoration of the phenotypes of chrR1::Tn5 and chrR2::Km mutants related to carotenoid biosynthesis and photooxidative stress tolerance by expressing chrR1 or chrR2 provided in vivo evidence for the cross-talk. In addition, up- or down-regulation of several identical proteins by expressing chrR1 or chrR2 in the chrR1::Tn5 mutant provided another in vivo evidence for the cross-talk. INNOVATION Although multiple redox-sensitive ZAS anti-σ factors occur in some Gram-positive bacteria, no cross-talk is reported among them. We report here, for the first time, that the two ZAS anti-σ factors of A. brasilense also interact with their noncognate σ factors and affect gene expression. CONCLUSION The two redox-sensitive ZAS anti-σ factors in A. brasilense may interact with their cognate as well as noncognate ECF σ factors to play an important role in redox homeostasis by facilitating recovery from the oxidative stress.
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Affiliation(s)
- Namrata Gupta
- Faculty of Science, School of Biotechnology, Banaras Hindu University , Varanasi, India
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