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Fernandez NL, Simmons LA. Two distinct regulatory systems control pulcherrimin biosynthesis in Bacillus subtilis. PLoS Genet 2024; 20:e1011283. [PMID: 38753885 PMCID: PMC11135676 DOI: 10.1371/journal.pgen.1011283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/29/2024] [Accepted: 05/03/2024] [Indexed: 05/18/2024] Open
Abstract
Regulation of transcription is a fundamental process that allows bacteria to respond to external stimuli with appropriate timing and magnitude of response. In the soil bacterium Bacillus subtilis, transcriptional regulation is at the core of developmental processes needed for cell survival. Gene expression in cells transitioning from exponential phase to stationary phase is under the control of a group of transcription factors called transition state regulators (TSRs). TSRs influence numerous developmental processes including the decision between biofilm formation and motility, genetic competence, and sporulation, but the extent to which TSRs influence bacterial physiology remains to be fully elucidated. Here, we demonstrate two TSRs, ScoC and AbrB, along with the MarR-family transcription factor PchR negatively regulate production of the iron chelator pulcherrimin in B. subtilis. Genetic analysis of the relationship between the three transcription factors indicate that all are necessary to limit pulcherrimin production during exponential phase and influence the rate and total amount of pulcherrimin produced. Similarly, expression of the pulcherrimin biosynthesis gene yvmC was found to be under control of ScoC, AbrB, and PchR and correlated with the amount of pulcherrimin produced by each background. Lastly, our in vitro data indicate a weak direct role for ScoC in controlling pulcherrimin production along with AbrB and PchR. The layered regulation by two distinct regulatory systems underscores the important role for pulcherrimin in B. subtilis physiology.
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Affiliation(s)
- Nicolas L. Fernandez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lyle A. Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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2
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Fernandez NL, Simmons LA. Two Distinct Regulatory Systems Control Pulcherrimin Biosynthesis in Bacillus subtilis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.574033. [PMID: 38260623 PMCID: PMC10802322 DOI: 10.1101/2024.01.03.574033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Regulation of transcription is a fundamental process that allows bacteria to respond to external stimuli with appropriate timing and magnitude of response. In the soil bacterium Bacillus subtilis, transcriptional regulation is at the core of developmental processes needed for cell survival. Gene expression in cells transitioning from exponential phase to stationary phase is under the control of a group of transcription factors called transition state regulators (TSRs). TSRs influence numerous developmental processes including the decision between biofilm formation and motility, genetic competence, and sporulation, but the extent to which TSRs influence bacterial physiology remains to be fully elucidated. Here, we demonstrate two TSRs, ScoC and AbrB, along with the MerR-family transcription factor PchR negatively regulate production of the iron chelator pulcherrimin in B. subtilis. Genetic analysis of the relationship between the three transcription factors indicate that all are necessary to limit pulcherrimin production during exponential phase and influence the rate and total amount of pulcherrimin produced. Similarly, expression of the pulcherrimin biosynthesis gene yvmC was found to be under control of ScoC, AbrB, and PchR and correlated with the amount of pulcherrimin produced by each background. Lastly, our in vitro data indicate a weak direct role for ScoC in controlling pulcherrimin production along with AbrB and PchR. The layered regulation by two distinct regulatory systems underscores the important, and somewhat enigmatic, role for pulcherrimin in B. subtilis physiology.
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Affiliation(s)
- Nicolas L. Fernandez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Lyle A. Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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3
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Surfactin Stimulated by Pectin Molecular Patterns and Root Exudates Acts as a Key Driver of the Bacillus-Plant Mutualistic Interaction. mBio 2021; 12:e0177421. [PMID: 34724831 PMCID: PMC8561381 DOI: 10.1128/mbio.01774-21] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Bacillus velezensis is considered as a model species belonging to the so-called Bacillus subtilis complex that evolved typically to dwell in the soil rhizosphere niche and establish an intimate association with plant roots. This bacterium provides protection to its natural host against diseases and represents one of the most promising biocontrol agents. However, the molecular basis of the cross talk that this bacterium establishes with its natural host has been poorly investigated. We show here that these plant-associated bacteria have evolved a polymer-sensing system to perceive their host and that, in response, they increase the production of the surfactin-type lipopeptide. Furthermore, we demonstrate that surfactin synthesis is favored upon growth on root exudates and that this lipopeptide is a key component used by the bacterium to optimize biofilm formation, motility, and early root colonization. In this specific nutritional context, the bacterium also modulates qualitatively the pattern of surfactin homologues coproduced in planta and forms mainly variants that are the most active at triggering plant immunity. Surfactin represents a shared good as it reinforces the defensive capacity of the host. IMPORTANCE Within the plant-associated microbiome, some bacterial species are of particular interest due to the disease protective effect they provide via direct pathogen suppression and/or stimulation of host immunity. While these biocontrol mechanisms are quite well characterized, we still poorly understand the molecular basis of the cross talk these beneficial bacteria initiate with their host. Here, we show that the model species Bacillus velezensis stimulates the production of the surfactin lipopeptide upon sensing pectin as a cell surface molecular pattern and upon feeding on root exudates. Surfactin favors bacterial rhizosphere fitness on one hand and primes the plant immune system on the other hand. Our data therefore illustrate how both partners use this multifunctional compound as a unique shared good to sustain a mutualistic interaction.
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4
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Sachla AJ, Alfonso AJ, Helmann JD. A Simplified Method for CRISPR-Cas9 Engineering of Bacillus subtilis. Microbiol Spectr 2021; 9:e0075421. [PMID: 34523974 PMCID: PMC8557940 DOI: 10.1128/spectrum.00754-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/16/2021] [Indexed: 11/20/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system from Streptococcus pyogenes has been widely deployed as a tool for bacterial strain construction. Conventional CRISPR-Cas9 editing strategies require design and molecular cloning of an appropriate guide RNA (gRNA) to target genome cleavage and a repair template for introduction of the desired site-specific genome modification. Here, we present a streamlined method that leverages the existing collection of nearly 4,000 Bacillus subtilis strains (the BKE collection) with individual genes replaced by an integrated erythromycin (erm) resistance cassette. A single plasmid (pAJS23) with a gRNA targeted to erm allows cleavage of the genome at any nonessential gene and at sites nearby to many essential genes. This plasmid can be engineered to include a repair template, or the repair template can be cotransformed with the plasmid as either a PCR product or genomic DNA. We demonstrate the utility of this system for generating gene replacements, site-specific mutations, modification of intergenic regions, and introduction of gene-reporter fusions. In sum, this strategy bypasses the need for gRNA design and allows the facile transfer of mutations and genetic constructions with no requirement for intermediate cloning steps. IMPORTANCE Bacillus subtilis is a well-characterized Gram-positive model organism and a popular platform for biotechnology. Although many different CRISPR-based genome editing strategies have been developed for B. subtilis, they generally involve the design and cloning of a specific guide RNA (gRNA) and repair template for each application. By targeting the erm resistance cassette with an anti-erm gRNA, genome editing can be directed to any of nearly 4,000 gene disruptants within the existing BKE collection of strains. Repair templates can be engineered as PCR products, or specific alleles and constructions can be transformed as chromosomal DNA, thereby bypassing the need for plasmid construction. The described method is rapid and facilitates a wide range of genome manipulations.
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Affiliation(s)
- Ankita J. Sachla
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | | | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, New York, USA
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5
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Babel H, Naranjo-Meneses P, Trauth S, Schulmeister S, Malengo G, Sourjik V, Bischofs IB. Ratiometric population sensing by a pump-probe signaling system in Bacillus subtilis. Nat Commun 2020; 11:1176. [PMID: 32132526 PMCID: PMC7055314 DOI: 10.1038/s41467-020-14840-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 02/04/2020] [Indexed: 12/20/2022] Open
Abstract
Communication by means of diffusible signaling molecules facilitates higher-level organization of cellular populations. Gram-positive bacteria frequently use signaling peptides, which are either detected at the cell surface or ‘probed’ by intracellular receptors after being pumped into the cytoplasm. While the former type is used to monitor cell density, the functions of pump-probe networks are less clear. Here we show that pump-probe networks can, in principle, perform different tasks and mediate quorum-sensing, chronometric and ratiometric control. We characterize the properties of the prototypical PhrA-RapA system in Bacillus subtilis using FRET. We find that changes in extracellular PhrA concentrations are tracked rather poorly; instead, cells accumulate and strongly amplify the signal in a dose-dependent manner. This suggests that the PhrA-RapA system, and others like it, have evolved to sense changes in the composition of heterogeneous populations and infer the fraction of signal-producing cells in a mixed population to coordinate cellular behaviors. Gram-positive bacteria can release signaling peptides that are ‘probed’ by intracellular receptors after being pumped into the cytoplasm. Here, Babel et al. show that these pump-probe networks can infer the fraction of signal-producing cells in a mixed population, and do not necessarily mediate typical quorum-sensing control.
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Affiliation(s)
- Heiko Babel
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Pablo Naranjo-Meneses
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Stephanie Trauth
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Sonja Schulmeister
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Gabriele Malengo
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.,LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch Str. 16, 35043, Marburg, Germany
| | - Victor Sourjik
- Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.,LOEWE Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch Str. 16, 35043, Marburg, Germany
| | - Ilka B Bischofs
- BioQuant Center of the University of Heidelberg, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany. .,Center for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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6
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Lytvynenko I, Paternoga H, Thrun A, Balke A, Müller TA, Chiang CH, Nagler K, Tsaprailis G, Anders S, Bischofs I, Maupin-Furlow JA, Spahn CMT, Joazeiro CAP. Alanine Tails Signal Proteolysis in Bacterial Ribosome-Associated Quality Control. Cell 2019; 178:76-90.e22. [PMID: 31155236 DOI: 10.1016/j.cell.2019.05.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/11/2019] [Accepted: 04/30/2019] [Indexed: 11/19/2022]
Abstract
In ribosome-associated quality control (RQC), Rqc2/NEMF closely supports the E3 ligase Ltn1/listerin in promoting ubiquitylation and degradation of aberrant nascent-chains obstructing large (60S) ribosomal subunits-products of ribosome stalling during translation. However, while Ltn1 is eukaryote-specific, Rqc2 homologs are also found in bacteria and archaea; whether prokaryotic Rqc2 has an RQC-related function has remained unknown. Here, we show that, as in eukaryotes, a bacterial Rqc2 homolog (RqcH) recognizes obstructed 50S subunits and promotes nascent-chain proteolysis. Unexpectedly, RqcH marks nascent-chains for degradation in a direct manner, by appending C-terminal poly-alanine tails that act as degrons recognized by the ClpXP protease. Furthermore, RqcH acts redundantly with tmRNA/ssrA and protects cells against translational and environmental stresses. Our results uncover a proteolytic-tagging mechanism with implications toward the function of related modifications in eukaryotes and suggest that RQC was already active in the last universal common ancestor (LUCA) to help cope with incomplete translation.
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Affiliation(s)
- Iryna Lytvynenko
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Helge Paternoga
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Anna Thrun
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Annika Balke
- Institut für Medizinische Physik und Biophysik, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Tina A Müller
- Department of Molecular Medicine, Scripps Research, Jupiter, FL 33458, USA
| | - Christina H Chiang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA 92037, USA
| | - Katja Nagler
- BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | | | - Simon Anders
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Ilka Bischofs
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science and Genetics Institute, University of Florida, Gainesville, FL 32611, USA
| | - Christian M T Spahn
- Institut für Medizinische Physik und Biophysik, Charité - Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Claudio A P Joazeiro
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Department of Molecular Medicine, Scripps Research, Jupiter, FL 33458, USA.
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7
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Mahipant G, Kato J, Kataoka N, Vangnai AS. An alternative genome-integrated method for undomesticated Bacillus subtilis and related species. J GEN APPL MICROBIOL 2019; 65:96-105. [PMID: 30487367 DOI: 10.2323/jgam.2018.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Given their applicability in genetic engineering, undomesticated Bacillus strains are extensively used as non-natural hosts for chemical production due to their high tolerance of toxic substrates or products. However, they are difficult to genomically modify due to their low transformation efficiencies. In this study, the Bacillus-E. coli shuttle vector pHY300PLK, which is widely used in gram-positive bacteria, was adopted for genome integration in organic solvent-tolerant Bacillus isolates. The Bacillus-replicative vector was used to deliver homologous recombinant DNA and propagate itself inside the host cell, increasing the likelihood of genome integration of the recombinant DNA. Then, the unintegrated vectors were cured by cell cultivation in antibiotic-free medium with facilitation of nickel ions. The developed protocol was successfully demonstrated and validated by the disruption of amyE gene in B. subtilis 168. With an improved clonal selection protocol, the probability of clonal selection of the amyE::cat genome-integrated mutants was increased up to 42.0 ± 10.2%. Genome integration in undomesticated, organic solvent tolerant Bacillus strains was also successfully demonstrated with amyE as well as proB gene creating the gene-disrupted mutants with the corresponding phenotype and genotype. Not only was this technique effectively applied to several strains of undomesticated B. subtilis, but it was also successfully applied to B. cereus. This study validates the possibility of the application of Bacillus-replicative vector as well as the developed protocol in a variety of genome modification of undomesticated Bacillus species.
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Affiliation(s)
- Gumpanat Mahipant
- Biological Sciences Program, Faculty of Science, Chulalongkorn University.,Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University
| | - Junichi Kato
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University
| | - Naoya Kataoka
- Division of Agricultural Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University
| | - Alisa S Vangnai
- Biocatalyst and Environmental Biotechnology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University.,Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University
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8
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Mutlu A, Trauth S, Ziesack M, Nagler K, Bergeest JP, Rohr K, Becker N, Höfer T, Bischofs IB. Phenotypic memory in Bacillus subtilis links dormancy entry and exit by a spore quantity-quality tradeoff. Nat Commun 2018; 9:69. [PMID: 29302032 PMCID: PMC5754360 DOI: 10.1038/s41467-017-02477-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/04/2017] [Indexed: 12/15/2022] Open
Abstract
Some bacteria, such as Bacillus subtilis, withstand starvation by forming dormant spores that revive when nutrients become available. Although sporulation and spore revival jointly determine survival in fluctuating environments, the relationship between them has been unclear. Here we show that these two processes are linked by a phenotypic “memory” that arises from a carry-over of molecules from the vegetative cell into the spore. By imaging life histories of individual B. subtilis cells using fluorescent reporters, we demonstrate that sporulation timing controls nutrient-induced spore revival. Alanine dehydrogenase contributes to spore memory and controls alanine-induced outgrowth, thereby coupling a spore’s revival capacity to the gene expression and growth history of its progenitors. A theoretical analysis, and experiments with signaling mutants exhibiting altered sporulation timing, support the hypothesis that such an intrinsically generated memory leads to a tradeoff between spore quantity and spore quality, which could drive the emergence of complex microbial traits. Bacillus subtilis withstands starvation by forming dormant spores that revive when nutrients become available. Here, Mutlu et al. show that sporulation timing controls spore revival through a phenotypic ‘memory’ that arises from the carry-over of a metabolic enzyme from the vegetative cell into the spore.
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Affiliation(s)
- Alper Mutlu
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Stephanie Trauth
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Marika Ziesack
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Center for Molecular Biology (ZMBH), University of Heidelberg, 69120, Heidelberg, Germany
| | - Katja Nagler
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Jan-Philip Bergeest
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Institute of Pharmacy and Molecular Biotechnology (IPMB), 69120, Heidelberg, Germany.,Department of Bioinformatics and Functional Genomics, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Karl Rohr
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Institute of Pharmacy and Molecular Biotechnology (IPMB), 69120, Heidelberg, Germany.,Department of Bioinformatics and Functional Genomics, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Nils Becker
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Division of Theoretical Systems Biology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Thomas Höfer
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Division of Theoretical Systems Biology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Ilka B Bischofs
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany. .,Center for Molecular Biology (ZMBH), University of Heidelberg, 69120, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
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Willson BJ, Kovács K, Wilding-Steele T, Markus R, Winzer K, Minton NP. Production of a functional cell wall-anchored minicellulosome by recombinant Clostridium acetobutylicum ATCC 824. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:109. [PMID: 27222664 PMCID: PMC4877998 DOI: 10.1186/s13068-016-0526-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 05/10/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND The use of fossil fuels is no longer tenable. Not only are they a finite resource, their use is damaging the environment through pollution and global warming. Alternative, environmentally friendly, renewable sources of chemicals and fuels are required. To date, the focus has been on using lignocellulose as a feedstock for microbial fermentation. However, its recalcitrance to deconstruction is making the development of economic processes extremely challenging. One solution is the generation of an organism suitable for use in consolidated bioprocessing (CBP), i.e. one able to both hydrolyse lignocellulose and ferment the released sugars, and this represents an important goal for synthetic biology. We aim to use synthetic biology to develop the solventogenic bacterium C. acetobutylicum as a CBP organism through the introduction of a cellulosome, a complex of cellulolytic enzymes bound to a scaffold protein called a scaffoldin. In previous work, we were able to demonstrate the in vivo production of a C. thermocellum-derived minicellulosome by recombinant strains of C. acetobutylicum, and aim to develop on this success, addressing potential issues with the previous strategy. RESULTS The genes for the cellulosomal enzymes Cel9G, Cel48F, and Xyn10A from C. cellulolyticum were integrated into the C. acetobutylicum genome using Allele-Coupled Exchange (ACE) technology, along with a miniscaffoldin derived from C. cellulolyticum CipC. The possibility of anchoring the recombinant cellulosome to the cell surface using the native sortase system was assessed, and the cellulolytic properties of the recombinant strains were assayed via plate growth, batch fermentation and sugar release assays. CONCLUSIONS We have been able to demonstrate the synthesis and in vivo assembly of a four-component minicellulosome by recombinant C. acetobutylicum strains. Furthermore, we have been able to anchor a minicellulosome to the C. acetobutylicum cell wall by the use of the native sortase system. The recombinant strains display an improved growth phenotype on xylan and an increase in released reducing sugar from several substrates including untreated powdered wheat straw. This constitutes an important milestone towards the development of a truly cellulolytic strain suitable for CBP.
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Affiliation(s)
- Benjamin J. Willson
- />Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
| | - Katalin Kovács
- />Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
| | - Tom Wilding-Steele
- />Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
| | - Robert Markus
- />SLIM Imaging Unit, Faculty of Medicine and Health Sciences, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
| | - Klaus Winzer
- />Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
| | - Nigel P. Minton
- />Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD UK
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10
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Wolf D, Rippa V, Mobarec JC, Sauer P, Adlung L, Kolb P, Bischofs IB. The quorum-sensing regulator ComA from Bacillus subtilis activates transcription using topologically distinct DNA motifs. Nucleic Acids Res 2015; 44:2160-72. [PMID: 26582911 PMCID: PMC4797271 DOI: 10.1093/nar/gkv1242] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/30/2015] [Indexed: 11/27/2022] Open
Abstract
ComA-like transcription factors regulate the quorum response in numerous Gram-positive bacteria. ComA proteins belong to the tetrahelical helix-turn-helix superfamily of transcriptional activators, which bind as homodimers to inverted sequence repeats in the DNA. Here, we report that ComA from Bacillus subtilis recognizes a topologically distinct motif, in which the binding elements form a direct repeat. We provide in vitro and in vivo evidence that the canonical and non-canonical site play an important role in facilitating type I and type II promoter activation, respectively, by interacting with different subunits of RNA polymerase. We furthermore show that there is a variety of contexts in which the non-canonical site can occur and identify new direct target genes that are located within the integrative and conjugative element ICEBs1. We therefore suggest that ComA acts as a multifunctional transcriptional activator and provides a striking example for complexity in protein–DNA interactions that evolved in the context of quorum sensing.
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Affiliation(s)
- Diana Wolf
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Valentina Rippa
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Juan Carlos Mobarec
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Patricia Sauer
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Lorenz Adlung
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, Philipps-University Marburg, Marbacher Weg 6, 35032 Marburg, Germany
| | - Ilka B Bischofs
- Center for Molecular Biology (ZMBH) and Center for the Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), University of Heidelberg, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
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