Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica
ABSTRACT The metabolic island GEI4417/4436 of Salmonella enterica serovar Typhimurium (S. Typhimurium) enables the degradation of myo-inositol (MI) as the sole carbon and energy source. The island encodes two regulatory factors, the autoregulated repressor IolR that inhibits the transcription of mos...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2024-01-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.02724-23 |
| _version_ | 1797357337743196160 |
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| author | Angela Felsl Dominik Brokatzky Carsten Kröger Ralf Heermann Thilo M. Fuchs |
| author_facet | Angela Felsl Dominik Brokatzky Carsten Kröger Ralf Heermann Thilo M. Fuchs |
| author_sort | Angela Felsl |
| collection | DOAJ |
| description | ABSTRACT The metabolic island GEI4417/4436 of Salmonella enterica serovar Typhimurium (S. Typhimurium) enables the degradation of myo-inositol (MI) as the sole carbon and energy source. The island encodes two regulatory factors, the autoregulated repressor IolR that inhibits the transcription of most iol genes in the absence of MI, and the activator ReiD that induces the expression of an iol gene operon that is not controlled by IolR. In this study, we investigated the putative role of global regulators in the control of MI utilization by S. Typhimurium. The histone-like nucleoid structuring protein H-NS is demonstrated here to interact with 16 regions of GEI4417/4436 and to silence the transcriptional activity of the promoters P reiD and P iolE , thus controlling the expression of genes initial for MI degradation. The cAMP-binding regulatory protein (CRP) is shown to bind numerous promoters in GEI4417/4436 and is required for the growth of S. Typhimurium strain 14028 in a minimal medium with MI. The binding kinetics of H-NS and CRP toward promoters of GEI4417/4436 were quantified by surface resonance spectroscopy, showing that H-NS weakly binds to promoters of initial genes and that CRP has a high affinity to promoters of all genes essential for MI utilization. Furthermore, three promoters of the metabolic island were identified here to belong to the virulon of the two-component system SsrA/SsrB of salmonellae as demonstrated by electrophoretic mobility shift assays and the use of chromosomal luciferase reporter fusions. IMPORTANCE The capacity to utilize myo-inositol (MI) as sole carbon and energy source is widespread among bacteria, among them the intestinal pathogen S. Typhimurium. This study elucidates the complex and hierarchical regulation that underlies the utilization of MI by S. Typhimurium under substrate limitation. A total of seven regulatory factors have been identified so far, allowing the pathogen an environment-dependent, efficient, and fine-tuned regulation of a metabolic property that provides growth advantages in different environments. |
| first_indexed | 2024-03-08T14:43:32Z |
| format | Article |
| id | doaj.art-0c78b602b3464bf68ea42160dd61b892 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-03-08T14:43:32Z |
| publishDate | 2024-01-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-0c78b602b3464bf68ea42160dd61b8922024-01-11T14:04:38ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972024-01-0112110.1128/spectrum.02724-23Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella entericaAngela Felsl0Dominik Brokatzky1Carsten Kröger2Ralf Heermann3Thilo M. Fuchs4Lehrstuhl für Mikrobielle Ökologie, ZIEL-Institute for Food and Health, School of Life Science, Technische Universität München , Freising, GermanyLehrstuhl für Mikrobielle Ökologie, ZIEL-Institute for Food and Health, School of Life Science, Technische Universität München , Freising, GermanyDepartment of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, University of Dublin , Dublin, IrelandJohannes Gutenberg University Mainz, Institute of Molecular Physiology (imP), Biocenter II, Microbiology and Biotechnology , Mainz, GermanyLehrstuhl für Mikrobielle Ökologie, ZIEL-Institute for Food and Health, School of Life Science, Technische Universität München , Freising, GermanyABSTRACT The metabolic island GEI4417/4436 of Salmonella enterica serovar Typhimurium (S. Typhimurium) enables the degradation of myo-inositol (MI) as the sole carbon and energy source. The island encodes two regulatory factors, the autoregulated repressor IolR that inhibits the transcription of most iol genes in the absence of MI, and the activator ReiD that induces the expression of an iol gene operon that is not controlled by IolR. In this study, we investigated the putative role of global regulators in the control of MI utilization by S. Typhimurium. The histone-like nucleoid structuring protein H-NS is demonstrated here to interact with 16 regions of GEI4417/4436 and to silence the transcriptional activity of the promoters P reiD and P iolE , thus controlling the expression of genes initial for MI degradation. The cAMP-binding regulatory protein (CRP) is shown to bind numerous promoters in GEI4417/4436 and is required for the growth of S. Typhimurium strain 14028 in a minimal medium with MI. The binding kinetics of H-NS and CRP toward promoters of GEI4417/4436 were quantified by surface resonance spectroscopy, showing that H-NS weakly binds to promoters of initial genes and that CRP has a high affinity to promoters of all genes essential for MI utilization. Furthermore, three promoters of the metabolic island were identified here to belong to the virulon of the two-component system SsrA/SsrB of salmonellae as demonstrated by electrophoretic mobility shift assays and the use of chromosomal luciferase reporter fusions. IMPORTANCE The capacity to utilize myo-inositol (MI) as sole carbon and energy source is widespread among bacteria, among them the intestinal pathogen S. Typhimurium. This study elucidates the complex and hierarchical regulation that underlies the utilization of MI by S. Typhimurium under substrate limitation. A total of seven regulatory factors have been identified so far, allowing the pathogen an environment-dependent, efficient, and fine-tuned regulation of a metabolic property that provides growth advantages in different environments.https://journals.asm.org/doi/10.1128/spectrum.02724-23myo-inositolH-NSCRPSsrA/SsrBmetabolic regulationmetabolism |
| spellingShingle | Angela Felsl Dominik Brokatzky Carsten Kröger Ralf Heermann Thilo M. Fuchs Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica Microbiology Spectrum myo-inositol H-NS CRP SsrA/SsrB metabolic regulation metabolism |
| title | Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica |
| title_full | Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica |
| title_fullStr | Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica |
| title_full_unstemmed | Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica |
| title_short | Hierarchic regulation of a metabolic pathway: H-NS, CRP, and SsrB control myo-inositol utilization by Salmonella enterica |
| title_sort | hierarchic regulation of a metabolic pathway h ns crp and ssrb control myo inositol utilization by salmonella enterica |
| topic | myo-inositol H-NS CRP SsrA/SsrB metabolic regulation metabolism |
| url | https://journals.asm.org/doi/10.1128/spectrum.02724-23 |
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