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Müller MC, Lemaire ON, Kurth JM, Welte CU, Wagner T. Differences in regulation mechanisms of glutamine synthetases from methanogenic archaea unveiled by structural investigations. Commun Biol 2024; 7:111. [PMID: 38243071 PMCID: PMC10799026 DOI: 10.1038/s42003-023-05726-w] [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: 06/28/2023] [Accepted: 12/19/2023] [Indexed: 01/21/2024] Open
Abstract
Glutamine synthetases (GS) catalyze the ATP-dependent ammonium assimilation, the initial step of nitrogen acquisition that must be under tight control to fit cellular needs. While their catalytic mechanisms and regulations are well-characterized in bacteria and eukaryotes, only limited knowledge exists in archaea. Here, we solved two archaeal GS structures and unveiled unexpected differences in their regulatory mechanisms. GS from Methanothermococcus thermolithotrophicus is inactive in its resting state and switched on by 2-oxoglutarate, a sensor of cellular nitrogen deficiency. The enzyme activation overlays remarkably well with the reported cellular concentration for 2-oxoglutarate. Its binding to an allosteric pocket reconfigures the active site through long-range conformational changes. The homolog from Methermicoccus shengliensis does not harbor the 2-oxoglutarate binding motif and, consequently, is 2-oxoglutarate insensitive. Instead, it is directly feedback-inhibited through glutamine recognition by the catalytic Asp50'-loop, a mechanism common to bacterial homologs, but absent in M. thermolithotrophicus due to residue substitution. Analyses of residue conservation in archaeal GS suggest that both regulations are widespread and not mutually exclusive. While the effectors and their binding sites are surprisingly different, the molecular mechanisms underlying their mode of action on GS activity operate on the same molecular determinants in the active site.
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Affiliation(s)
- Marie-Caroline Müller
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany
| | - Olivier N Lemaire
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany
| | - Julia M Kurth
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Microcosm Earth Center, Philipps-University Marburg and Max Planck Institute for Terrestrial Microbiology, Hans-Meerwein-Str. 4, 35032, Marburg, Germany
| | - Cornelia U Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Tristan Wagner
- Microbial Metabolism Research Group, Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany.
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2
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Ghandour R, Papenfort K. Small regulatory RNAs in Vibrio cholerae. MICROLIFE 2023; 4:uqad030. [PMID: 37441523 PMCID: PMC10335731 DOI: 10.1093/femsml/uqad030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023]
Abstract
Vibrio cholerae is a major human pathogen causing the diarrheal disease, cholera. Regulation of virulence in V. cholerae is a multifaceted process involving gene expression changes at the transcriptional and post-transcriptional level. Whereas various transcription factors have been reported to modulate virulence in V. cholerae, small regulatory RNAs (sRNAs) have now been established to also participate in virulence control and the regulation of virulence-associated processes, such as biofilm formation, quorum sensing, stress response, and metabolism. In most cases, these sRNAs act by base-pairing with multiple target transcripts and this process typically requires the aid of an RNA-binding protein, such as the widely conserved Hfq protein. This review article summarizes the functional roles of sRNAs in V. cholerae, their underlying mechanisms of gene expression control, and how sRNAs partner with transcription factors to modulate complex regulatory programs. In addition, we will discuss regulatory principles discovered in V. cholerae that not only apply to other Vibrio species, but further extend into the large field of RNA-mediated gene expression control in bacteria.
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Affiliation(s)
- Rabea Ghandour
- Friedrich Schiller University Jena, Institute of Microbiology, 07745 Jena, Germany
| | - Kai Papenfort
- Corresponding author. Institute of Microbiology, General Microbiology, Friedrich Schiller University Jena, Winzerlaer Straße 2, 07745 Jena, Germany. Tel: +49-3641-949-311; E-mail:
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3
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Comparative Transcriptomics Sheds Light on Remodeling of Gene Expression during Diazotrophy in the Thermophilic Methanogen Methanothermococcus thermolithotrophicus. mBio 2022; 13:e0244322. [PMID: 36409126 PMCID: PMC9765008 DOI: 10.1128/mbio.02443-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Some marine thermophilic methanogens are able to perform energy-consuming nitrogen fixation despite deriving only little energy from hydrogenotrophic methanogenesis. We studied this process in Methanothermococcus thermolithotrophicus DSM 2095, a methanogenic archaeon of the order Methanococcales that contributes to the nitrogen pool in some marine environments. We successfully grew this archaeon under diazotrophic conditions in both batch and fermenter cultures, reaching the highest cell density reported so far. Diazotrophic growth depended strictly on molybdenum and, in contrast to other diazotrophs, was not inhibited by tungstate or vanadium. This suggests an elaborate control of metal uptake and a specific metal recognition system for the insertion into the nitrogenase cofactor. Differential transcriptomics of M. thermolithotrophicus grown under diazotrophic conditions with ammonium-fed cultures as controls revealed upregulation of the nitrogenase machinery, including chaperones, regulators, and molybdate importers, as well as simultaneous upregulation of an ammonium transporter and a putative pathway for nitrate and nitrite utilization. The organism thus employs multiple synergistic strategies for uptake of nitrogen nutrients during the early exponential growth phase without altering transcription levels for genes involved in methanogenesis. As a counterpart, genes coding for transcription and translation processes were downregulated, highlighting the maintenance of an intricate metabolic balance to deal with energy constraints and nutrient limitations imposed by diazotrophy. This switch in the metabolic balance included unexpected processes, such as upregulation of the CRISPR-Cas system, probably caused by drastic changes in transcription levels of putative mobile and virus-like elements. IMPORTANCE The thermophilic anaerobic archaeon M. thermolithotrophicus is a particularly suitable model organism to study the coupling of methanogenesis to diazotrophy. Likewise, its capability of simultaneously reducing N2 and CO2 into NH3 and CH4 with H2 makes it a viable target for biofuel production. We optimized M. thermolithotrophicus cultivation, resulting in considerably higher cell yields and enabling the successful establishment of N2-fixing bioreactors. Improved understanding of the N2 fixation process would provide novel insights into metabolic adaptations that allow this energy-limited extremophile to thrive under diazotrophy, for instance, by investigating its physiology and uncharacterized nitrogenase. We demonstrated that diazotrophic growth of M. thermolithotrophicus is exclusively dependent on molybdenum, and complementary transcriptomics corroborated the expression of the molybdenum nitrogenase system. Further analyses of differentially expressed genes during diazotrophy across three cultivation time points revealed insights into the response to nitrogen limitation and the coordination of core metabolic processes.
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4
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Coronel-Tellez RH, Pospiech M, Barrault M, Liu W, Bordeau V, Vasnier C, Felden B, Sargueil B, Bouloc P. sRNA-controlled iron sparing response in Staphylococci. Nucleic Acids Res 2022; 50:8529-8546. [PMID: 35904807 PMCID: PMC9410917 DOI: 10.1093/nar/gkac648] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 07/06/2022] [Accepted: 07/19/2022] [Indexed: 11/14/2022] Open
Abstract
Staphylococcus aureus, a human opportunist pathogen, adjusts its metabolism to cope with iron deprivation within the host. We investigated the potential role of small non-coding RNAs (sRNAs) in dictating this process. A single sRNA, named here IsrR, emerged from a competition assay with tagged-mutant libraries as being required during iron starvation. IsrR is iron-repressed and predicted to target mRNAs expressing iron-containing enzymes. Among them, we demonstrated that IsrR down-regulates the translation of mRNAs of enzymes that catalyze anaerobic nitrate respiration. The IsrR sequence reveals three single-stranded C-rich regions (CRRs). Mutational and structural analysis indicated a differential contribution of these CRRs according to targets. We also report that IsrR is required for full lethality of S. aureus in a mouse septicemia model, underscoring its role as a major contributor to the iron-sparing response for bacterial survival during infection. IsrR is conserved among staphylococci, but it is not ortholog to the proteobacterial sRNA RyhB, nor to other characterized sRNAs down-regulating mRNAs of iron-containing enzymes. Remarkably, these distinct sRNAs regulate common targets, illustrating that RNA-based regulation provides optimal evolutionary solutions to improve bacterial fitness when iron is scarce.
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Affiliation(s)
- Rodrigo H Coronel-Tellez
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) 91198, Gif-sur-Yvette, France
| | - Mateusz Pospiech
- CNRS UMR 8038, CitCoM, Université Paris Cité 75006, Paris, France
| | - Maxime Barrault
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) 91198, Gif-sur-Yvette, France
| | - Wenfeng Liu
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) 91198, Gif-sur-Yvette, France
| | - Valérie Bordeau
- Université de Rennes 1, BRM (Bacterial regulatory RNAs and Medicine) UMR_S 1230 35000, Rennes, France
| | | | - Brice Felden
- Université de Rennes 1, BRM (Bacterial regulatory RNAs and Medicine) UMR_S 1230 35000, Rennes, France
| | - Bruno Sargueil
- CNRS UMR 8038, CitCoM, Université Paris Cité 75006, Paris, France
| | - Philippe Bouloc
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) 91198, Gif-sur-Yvette, France
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5
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Han Y, Li C, Yan Y, Lin M, Ke X, Zhang Y, Zhan Y. Post-transcriptional control of bacterial nitrogen metabolism by regulatory noncoding RNAs. World J Microbiol Biotechnol 2022; 38:126. [PMID: 35666348 PMCID: PMC9170634 DOI: 10.1007/s11274-022-03287-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/12/2022] [Indexed: 12/04/2022]
Abstract
Nitrogen metabolism is the most basic process of material and energy metabolism in living organisms, and processes involving the uptake and use of different nitrogen sources are usually tightly regulated at the transcriptional and post-transcriptional levels. Bacterial regulatory noncoding RNAs are novel post-transcriptional regulators that repress or activate the expression of target genes through complementarily pairing with target mRNAs; therefore, these noncoding RNAs play an important regulatory role in many physiological processes, such as bacterial substance metabolism and stress response. In recent years, a study found that noncoding RNAs play a vital role in the post-transcriptional regulation of nitrogen metabolism, which is currently a hot topic in the study of bacterial nitrogen metabolism regulation. In this review, we present an overview of recent advances that increase our understanding on the regulatory roles of bacterial noncoding RNAs and describe in detail how noncoding RNAs regulate biological nitrogen fixation and nitrogen metabolic engineering. Furthermore, our goal is to lay a theoretical foundation for better understanding the molecular mechanisms in bacteria that are involved in environmental adaptations and metabolically-engineered genetic modifications.
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Affiliation(s)
- Yueyue Han
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chao Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongliang Yan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Min Lin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiubin Ke
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yunhua Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China. .,School of Resources and Environment, Anhui Agricultural University, Hefei, China.
| | - Yuhua Zhan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
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6
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Hagberg KL, Price JP, Yurgel SN, Kahn ML. The Sinorhizobium meliloti Nitrogen Stress Response Changes Radically in the Face of Concurrent Phosphate Stress. Front Microbiol 2022; 13:800146. [PMID: 35154051 PMCID: PMC8829014 DOI: 10.3389/fmicb.2022.800146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Abstract
Expression of hundreds of S. meliloti genes changed more than two-fold in response to either nitrogen or phosphate limitation. When these two stresses were applied together, stress responsive gene expression shifted dramatically. In particular, the nitrogen stress response in the presence of phosphate stress had only 30 of about 350 genes in common with the 280 genes that responded to nitrogen stress with adequate phosphate. Expression of sRNAs was also altered in response to these stresses. 82% of genes that responded to nitrogen stress also responded to phosphate stress, including 20 sRNAs. A subset of these sRNAs is known to be chaperoned by the RNA binding protein, Hfq. Hfq had previously been shown to influence about a third of the genes that responded to both nitrogen and phosphate stresses. Phosphate limitation influenced changes in gene expression more than nitrogen limitation and, when both stresses were present, phosphate stress sometimes reversed the direction of some of the changes induced by nitrogen stress. These nutrient stress responses are therefore context dependent.
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Affiliation(s)
- Kelly L. Hagberg
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Jason P. Price
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Svetlana N. Yurgel
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- Department of Plant, Food and Environmental Sciences, Dalhousie University, Truro, NS, Canada
| | - Michael L. Kahn
- School of Molecular Biosciences, Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
- *Correspondence: Michael L. Kahn,
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7
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Miyakoshi M, Morita T, Kobayashi A, Berger A, Takahashi H, Gotoh Y, Hayashi T, Tanaka K. Glutamine synthetase mRNA releases sRNA from its 3'UTR to regulate carbon/nitrogen metabolic balance in Enterobacteriaceae. eLife 2022; 11:82411. [PMID: 36440827 PMCID: PMC9731577 DOI: 10.7554/elife.82411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/27/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamine synthetase (GS) is the key enzyme of nitrogen assimilation induced under nitrogen limiting conditions. The carbon skeleton of glutamate and glutamine, 2-oxoglutarate, is supplied from the TCA cycle, but how this metabolic flow is controlled in response to nitrogen availability remains unknown. We show that the expression of the E1o component of 2-oxoglutarate dehydrogenase, SucA, is repressed under nitrogen limitation in Salmonella enterica and Escherichia coli. The repression is exerted at the post-transcriptional level by an Hfq-dependent sRNA GlnZ generated from the 3'UTR of the GS-encoding glnA mRNA. Enterobacterial GlnZ variants contain a conserved seed sequence and primarily regulate sucA through base-pairing far upstream of the translation initiation region. During growth on glutamine as the nitrogen source, the glnA 3'UTR deletion mutants expressed SucA at higher levels than the S. enterica and E. coli wild-type strains, respectively. In E. coli, the transcriptional regulator Nac also participates in the repression of sucA. Lastly, this study clarifies that the release of GlnZ from the glnA mRNA by RNase E is essential for the post-transcriptional regulation of sucA. Thus, the mRNA coordinates the two independent functions to balance the supply and demand of the fundamental metabolites.
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Affiliation(s)
- Masatoshi Miyakoshi
- Department of Infection Biology, Faculty of Medicine, University of TsukubaTsukubaJapan,Transborder Medical Research Center, University of TsukubaTsukubaJapan,International Joint Degree Master’s Program in Agro-Biomedical Science in Food and Health (GIP-TRIAD), University of TsukubaTsukubaJapan
| | - Teppei Morita
- Institute for Advanced Biosciences, Keio UniversityTsuruokaJapan,Graduate School of Media and Governance, Keio UniversityFujisawaJapan
| | - Asaki Kobayashi
- Transborder Medical Research Center, University of TsukubaTsukubaJapan
| | - Anna Berger
- International Joint Degree Master’s Program in Agro-Biomedical Science in Food and Health (GIP-TRIAD), University of TsukubaTsukubaJapan
| | | | - Yasuhiro Gotoh
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu UniversityFukuokaJapan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu UniversityFukuokaJapan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of TechnologyYokohamaJapan
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8
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Durand S, Guillier M. Transcriptional and Post-transcriptional Control of the Nitrate Respiration in Bacteria. Front Mol Biosci 2021; 8:667758. [PMID: 34026838 PMCID: PMC8139620 DOI: 10.3389/fmolb.2021.667758] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/29/2021] [Indexed: 12/02/2022] Open
Abstract
In oxygen (O2) limiting environments, numerous aerobic bacteria have the ability to shift from aerobic to anaerobic respiration to release energy. This process requires alternative electron acceptor to replace O2 such as nitrate (NO3 -), which has the next best reduction potential after O2. Depending on the organism, nitrate respiration involves different enzymes to convert NO3 - to ammonium (NH4 +) or dinitrogen (N2). The expression of these enzymes is tightly controlled by transcription factors (TFs). More recently, bacterial small regulatory RNAs (sRNAs), which are important regulators of the rapid adaptation of microorganisms to extremely diverse environments, have also been shown to control the expression of genes encoding enzymes or TFs related to nitrate respiration. In turn, these TFs control the synthesis of multiple sRNAs. These results suggest that sRNAs play a central role in the control of these metabolic pathways. Here we review the complex interplay between the transcriptional and the post-transcriptional regulators to efficiently control the respiration on nitrate.
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Affiliation(s)
- Sylvain Durand
- CNRS, UMR 8261, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Maude Guillier
- CNRS, UMR 8261, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
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9
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Steinberg R, Koch HG. The largely unexplored biology of small proteins in pro- and eukaryotes. FEBS J 2021; 288:7002-7024. [PMID: 33780127 DOI: 10.1111/febs.15845] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/29/2022]
Abstract
The large abundance of small open reading frames (smORFs) in prokaryotic and eukaryotic genomes and the plethora of smORF-encoded small proteins became only apparent with the constant advancements in bioinformatic, genomic, proteomic, and biochemical tools. Small proteins are typically defined as proteins of < 50 amino acids in prokaryotes and of less than 100 amino acids in eukaryotes, and their importance for cell physiology and cellular adaptation is only beginning to emerge. In contrast to antimicrobial peptides, which are secreted by prokaryotic and eukaryotic cells for combatting pathogens and competitors, small proteins act within the producing cell mainly by stabilizing protein assemblies and by modifying the activity of larger proteins. Production of small proteins is frequently linked to stress conditions or environmental changes, and therefore, cells seem to use small proteins as intracellular modifiers for adjusting cell metabolism to different intra- and extracellular cues. However, the size of small proteins imposes a major challenge for the cellular machinery required for protein folding and intracellular trafficking and recent data indicate that small proteins can engage distinct trafficking pathways. In the current review, we describe the diversity of small proteins in prokaryotes and eukaryotes, highlight distinct and common features, and illustrate how they are handled by the protein trafficking machineries in prokaryotic and eukaryotic cells. Finally, we also discuss future topics of research on this fascinating but largely unexplored group of proteins.
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Affiliation(s)
- Ruth Steinberg
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
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10
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Sun X, Li R, Wan G, Peng W, Lin S, Deng Z, Liang R. Spot 42 RNA regulates putrescine catabolism in Escherichia coli by controlling the expression of puuE at the post-transcription level. J Microbiol 2021; 59:175-185. [PMID: 33527317 DOI: 10.1007/s12275-021-0421-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/16/2020] [Accepted: 12/11/2020] [Indexed: 10/22/2022]
Abstract
Putrescine, a typical polyamine compound important for cell growth and stress resistance, can be utilized as an energy source. However, the regulation of its catabolism is unclear. Here the small RNA (sRNA) Spot 42, an essential regulator of carbon catabolite repression (CCR), was confirmed to participate in the post-transcriptional regulation of putrescine catabolism in Escherichia coli. Its encoding gene spf exclusively exists in the γ-proteobacteria and contains specific binding sites to the 5'-untranslated regions of the puuE gene, which encodes transaminase in the glutamylated putrescine pathway of putrescine catabolism converting γ-aminobutyrate (GABA) into succinate semialdehyde (SSA). The transcription of the spf gene was induced by glucose, inhibited by putrescine, and unaffected by PuuR, the repressor of puu genes. Excess Spot 42 repressed the expression of PuuE significantly in an antisense mechanism through the direct and specific base-pairing between the 51`-57 nt of Spot 42 and the 5'-UTR of puuE. Interestingly, Spot 42 mainly influenced the stability of the puuCBE transcript. This work revealed the regulatory role of Spot 42 in putrescine catabolism, in the switch between favorable and non-favorable carbon source utilization, and in the balance of metabolism of carbon and nitrogen sources.
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Affiliation(s)
- Xin Sun
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Ruyan Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Guochen Wan
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Wanli Peng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Shuangjun Lin
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China
| | - Rubing Liang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P. R. China.
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11
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Global control of bacterial nitrogen and carbon metabolism by a PTS Ntr-regulated switch. Proc Natl Acad Sci U S A 2020; 117:10234-10245. [PMID: 32341157 DOI: 10.1073/pnas.1917471117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nitrogen-related phosphotransferase system (PTSNtr) of Rhizobium leguminosarum bv. viciae 3841 transfers phosphate from PEP via PtsP and NPr to two output regulators, ManX and PtsN. ManX controls central carbon metabolism via the tricarboxylic acid (TCA) cycle, while PtsN controls nitrogen uptake, exopolysaccharide production, and potassium homeostasis, each of which is critical for cellular adaptation and survival. Cellular nitrogen status modulates phosphorylation when glutamine, an abundant amino acid when nitrogen is available, binds to the GAF sensory domain of PtsP, preventing PtsP phosphorylation and subsequent modification of ManX and PtsN. Under nitrogen-rich, carbon-limiting conditions, unphosphorylated ManX stimulates the TCA cycle and carbon oxidation, while unphosphorylated PtsN stimulates potassium uptake. The effects are reversed with the phosphorylation of ManX and PtsN, occurring under nitrogen-limiting, carbon-rich conditions; phosphorylated PtsN triggers uptake and nitrogen metabolism, the TCA cycle and carbon oxidation are decreased, while carbon-storage polymers such as surface polysaccharide are increased. Deleting the GAF domain from PtsP makes cells "blind" to the cellular nitrogen status. PTSNtr constitutes a switch through which carbon and nitrogen metabolism are rapidly, and reversibly, regulated by protein:protein interactions. PTSNtr is widely conserved in proteobacteria, highlighting its global importance.
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12
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New proposal of nitrogen metabolism regulation by small RNAs in the extreme halophilic archaeon Haloferax mediterranei. Mol Genet Genomics 2020; 295:775-785. [DOI: 10.1007/s00438-020-01659-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/27/2020] [Indexed: 12/16/2022]
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13
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Hwang S, Chavarria NE, Hackley RK, Schmid AK, Maupin-Furlow JA. Gene Expression of Haloferax volcanii on Intermediate and Abundant Sources of Fixed Nitrogen. Int J Mol Sci 2019; 20:ijms20194784. [PMID: 31561502 PMCID: PMC6801745 DOI: 10.3390/ijms20194784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 09/20/2019] [Indexed: 12/17/2022] Open
Abstract
Haloferax volcanii, a well-developed model archaeon for genomic, transcriptomic, and proteomic analyses, can grow on a defined medium of abundant and intermediate levels of fixed nitrogen. Here we report a global profiling of gene expression of H. volcanii grown on ammonium as an abundant source of fixed nitrogen compared to l-alanine, the latter of which exemplifies an intermediate source of nitrogen that can be obtained from dead cells in natural habitats. By comparing the two growth conditions, 30 genes were found to be differentially expressed, including 16 genes associated with amino acid metabolism and transport. The gene expression profiles contributed to mapping ammonium and l-alanine usage with respect to transporters and metabolic pathways. In addition, conserved DNA motifs were identified in the putative promoter regions and transcription factors were found to be in synteny with the differentially expressed genes, leading us to propose regulons of transcriptionally co-regulated operons. This study provides insight to how H. volcanii responds to and utilizes intermediate vs. abundant sources of fixed nitrogen for growth, with implications for conserved functions in related halophilic archaea.
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Affiliation(s)
- Sungmin Hwang
- Department of Biology, Duke University, Durham, NC 27708, USA.
| | - Nikita E Chavarria
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.
| | - Rylee K Hackley
- Department of Biology, Duke University, Durham, NC 27708, USA.
- University Program in Genetics and Genomics, Duke University, Durham, NC 27708, USA.
| | - Amy K Schmid
- Department of Biology, Duke University, Durham, NC 27708, USA.
- University Program in Genetics and Genomics, Duke University, Durham, NC 27708, USA.
- Center for Genomics and Computational Biology, Duke University, Duke University, Durham, NC 27708, USA.
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA.
- Genetics Institute, University of Florida, Gainesville, FL 32611, USA.
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Kliemt J, Jaschinski K, Soppa J. A Haloarchaeal Small Regulatory RNA (sRNA) Is Essential for Rapid Adaptation to Phosphate Starvation Conditions. Front Microbiol 2019; 10:1219. [PMID: 31231327 PMCID: PMC6560208 DOI: 10.3389/fmicb.2019.01219] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/15/2019] [Indexed: 11/26/2022] Open
Abstract
The haloarchaeon Haloferax volcanii contains nearly 2800 small non-coding RNAs (sRNAs). One intergenic sRNA, sRNA132, was chosen for a detailed characterization. A deletion mutant had a growth defect and thus underscored the importance of sRNA132. A microarray analysis identified the transcript of an operon for a phosphate-specific ABC transporter as a putative target of sRNA132. Both the sRNA132 and the operon transcript accumulated under low phosphate concentrations, indicating a positive regulatory role of sRNA132. A kinetic analysis revealed that sRNA132 is essential shortly after the onset of phosphate starvation, while other regulatory processes take over after several hours. Comparison of the transcriptomes of wild-type and the sRNA132 gene deletion mutant 30 min after the onset of phosphate starvation revealed that sRNA132 controls a regulon of about 40 genes. Remarkably, the regulon included a second operon for a phosphate-specific ABC transporter, which also depended on sRNA132 for rapid induction in the absence of phosphate. Competitive growth experiments of the wild-type and ABC transporter operon deletion mutants underscored the importance of both transporters for growth at low phosphate concentrations. Northern blot analyses of four additional members of the sRNA132 regulon verified that all four transcripts depended on sRNA132 for rapid regulation after the onset of phosphate starvation. Importantly, this is the first example for the transient importance of a sRNA for any archaeal and bacterial species. In addition, this study unraveled the first sRNA regulon for haloarchaea.
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Affiliation(s)
- Jana Kliemt
- Biocentre, Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Katharina Jaschinski
- Biocentre, Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Jörg Soppa
- Biocentre, Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt, Germany
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Bolay P, Muro-Pastor MI, Florencio FJ, Klähn S. The Distinctive Regulation of Cyanobacterial Glutamine Synthetase. Life (Basel) 2018; 8:E52. [PMID: 30373240 PMCID: PMC6316151 DOI: 10.3390/life8040052] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 12/02/2022] Open
Abstract
Glutamine synthetase (GS) features prominently in bacterial nitrogen assimilation as it catalyzes the entry of bioavailable nitrogen in form of ammonium into cellular metabolism. The classic example, the comprehensively characterized GS of enterobacteria, is subject to exquisite regulation at multiple levels, among them gene expression regulation to control GS abundance, as well as feedback inhibition and covalent modifications to control enzyme activity. Intriguingly, the GS of the ecologically important clade of cyanobacteria features fundamentally different regulatory systems to those of most prokaryotes. These include the interaction with small proteins, the so-called inactivating factors (IFs) that inhibit GS linearly with their abundance. In addition to this protein interaction-based regulation of GS activity, cyanobacteria use alternative elements to control the synthesis of GS and IFs at the transcriptional level. Moreover, cyanobacteria evolved unique RNA-based regulatory mechanisms such as glutamine riboswitches to tightly tune IF abundance. In this review, we aim to outline the current knowledge on the distinctive features of the cyanobacterial GS encompassing the overall control of its activity, sensing the nitrogen status, transcriptional and post-transcriptional regulation, as well as strain-specific differences.
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Affiliation(s)
- Paul Bolay
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Permoserstrasse 15, D-04318 Leipzig, Germany.
| | - M Isabel Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
| | - Stephan Klähn
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Permoserstrasse 15, D-04318 Leipzig, Germany.
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