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Liang Z, Zheng K, Xie G, Luo X, Li H. Sugar Utilization-Associated Food-Grade Selection Markers in Lactic Acid Bacteria and Yeast. Pol J Microbiol 2024; 73:3-10. [PMID: 38437472 PMCID: PMC10911659 DOI: 10.33073/pjm-2024-011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/27/2024] [Indexed: 03/06/2024] Open
Abstract
This comprehensive review explores the development of food-grade selection markers in lactic acid bacteria and yeast; some of their strains are precisely defined as safe microorganisms and are crucial in the food industry. Lactic acid bacteria, known for their ability to ferment carbohydrates into lactic acid, provide essential nutrients and contribute to immune responses. With its strong fermentation capabilities and rich nutritional profile, yeast finds use in various food products. Genetic engineering in these microorganisms has grown rapidly, enabling the expression of enzymes and secondary products for food production. However, the focus is on ensuring safety, necessitating food-grade selection markers. Traditional antibiotic and heavy metal resistance selection markers pose environmental and health risks, prompting the search for safer alternatives. Complementary selection markers, such as sugar utilization markers, offer a promising solution. These markers use carbohydrates as carbon sources for growth and are associated with the natural metabolism of lactic acid bacteria and yeast. This review discusses the use of specific sugars, such as lactose, melibiose, sucrose, D-xylose, glucosamine, and N-acetylglucosamine, as selection markers, highlighting their advantages and limitations. In summary, this review underscores the importance of food-grade selection markers in genetic engineering and offers insights into their applications, benefits, and challenges, providing valuable information for researchers in the field of food microbiology and biotechnology.
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Affiliation(s)
- Zhiwen Liang
- School of Life and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Ke Zheng
- School of Life and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Guifeng Xie
- Guangzhou MEIZHONG Biotechnology Co., Ltd, Guangzhou, China
| | - Xiongsheng Luo
- Guangzhou MEIZHONG Biotechnology Co., Ltd, Guangzhou, China
| | - Huangjin Li
- School of Life and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
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2
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Jaworska K, Konarska J, Gomza P, Rożen P, Nieckarz M, Krawczyk-Balska A, Brzostek K, Raczkowska A. Interplay between the RNA Chaperone Hfq, Small RNAs and Transcriptional Regulator OmpR Modulates Iron Homeostasis in the Enteropathogen Yersinia enterocolitica. Int J Mol Sci 2023; 24:11157. [PMID: 37446335 DOI: 10.3390/ijms241311157] [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: 06/19/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Iron is both essential for and potentially toxic to bacteria, so the precise maintenance of iron homeostasis is necessary for their survival. Our previous study indicated that in the human enteropathogen Yersinia enterocolitica, the regulator OmpR directly controls the transcription of the fur, fecA and fepA genes, encoding the ferric uptake repressor and two transporters of ferric siderophores, respectively. This study was undertaken to determine the significance of the RNA chaperone Hfq and the small RNAs OmrA and RyhB1 in the post-transcriptional control of the expression of these OmpR targets. We show that Hfq silences fur, fecA and fepA expression post-transcriptionally and negatively affects the production of FLAG-tagged Fur, FecA and FepA proteins. In addition, we found that the fur gene is under the negative control of the sRNA RyhB1, while fecA and fepA are negatively regulated by the sRNA OmrA. Finally, our data revealed that the role of OmrA results from a complex interplay of transcriptional and post-transcriptional effects in the feedback circuit between the regulator OmpR and the sRNA OmrA. Thus, the expression of fur, fecA and fepA is subject to complex transcriptional and post-transcriptional regulation in order to maintain iron homeostasis in Y. enterocolitica.
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Affiliation(s)
- Karolina Jaworska
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Julia Konarska
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Patrycja Gomza
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Paula Rożen
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Marta Nieckarz
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Agata Krawczyk-Balska
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Katarzyna Brzostek
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Adrianna Raczkowska
- Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
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Gu Y, Zhang B, Tian J, Li L, He Y. Physiology, quorum sensing, and proteomics of lactic acid bacteria were affected by Saccharomyces cerevisiae YE4. Food Res Int 2023; 166:112612. [PMID: 36914328 DOI: 10.1016/j.foodres.2023.112612] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 02/25/2023]
Abstract
The interaction mode between lactic acid bacteria (LAB) and yeast in a fermentation system directly determines the quality of the products, thus understanding their mode of interaction can improve product quality. The present study investigated the effects of Saccharomyces cerevisiae YE4 on LAB from the perspectives of physiology, quorum sensing (QS), and proteomics. The presence of S. cerevisiae YE4 slowed down the growth of Enterococcus faecium 8-3 but had no significant effect on acid production or biofilm formation. S. cerevisiae YE4 significantly reduced the activity of autoinducer-2 at 19 h in E. faecium 8-3 and at 7-13 h in Lactobacillus fermentum 2-1. Expression of the QS-related genes luxS and pfs was also inhibited at 7 h. Moreover, a total of 107 E. faecium 8-3 proteins differed significantly in coculture with S. cerevisiae YE4-these proteins are involved in metabolic pathways including biosynthesis of secondary metabolites; biosynthesis of amino acids; alanine, aspartate, and glutamate metabolism; fatty acid metabolism; and fatty acid biosynthesis. Among them, proteins involved in cell adhesion, cell wall formation, two-component systems, and ABC transporters were detected. Therefore, S. cerevisiae YE4 might affect the physiological metabolism of E. faecium 8-3 by affecting cell adhesion, cell wall formation, and cell-cell interactions.
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Affiliation(s)
- Yue Gu
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Baojun Zhang
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Jianjun Tian
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China
| | - Lijie Li
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China.
| | - Yinfeng He
- College of Food Science and Engineering, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, Inner Mongolia 010018, China.
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Mahendran G, Jayasinghe OT, Thavakumaran D, Arachchilage GM, Silva GN. Key players in regulatory RNA realm of bacteria. Biochem Biophys Rep 2022; 30:101276. [PMID: 35592614 PMCID: PMC9111926 DOI: 10.1016/j.bbrep.2022.101276] [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: 02/10/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022] Open
Abstract
Precise regulation of gene expression is crucial for living cells to adapt for survival in diverse environmental conditions. Among the common cellular regulatory mechanisms, RNA-based regulators play a key role in all domains of life. Discovery of regulatory RNAs have made a paradigm shift in molecular biology as many regulatory functions of RNA have been identified beyond its canonical roles as messenger, ribosomal and transfer RNA. In the complex regulatory RNA network, riboswitches, small RNAs, and RNA thermometers can be identified as some of the key players. Herein, we review the discovery, mechanism, and potential therapeutic use of these classes of regulatory RNAs mainly found in bacteria. Being highly adaptive organisms that inhabit a broad range of ecological niches, bacteria have adopted tight and rapid-responding gene regulation mechanisms. This review aims to highlight how bacteria utilize versatile RNA structures and sequences to build a sophisticated gene regulation network. The three major classes of prokaryotic ncRNAs and their characterized mechanisms of operation in gene regulation. sRNAs emerging as major players in global gene regulatory networks. Riboswitch mediated gene control mechanisms through on/off switches in response to ligand binding. RNA thermo sensors for temperature-dependent gene expression. Therapeutic importance of ncRNAs and computational approaches involved in the discovery of ncRNAs.
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Affiliation(s)
- Gowthami Mahendran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Oshadhi T. Jayasinghe
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Dhanushika Thavakumaran
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Department of Chemistry and Biochemistry, University of Notre Dame, IN, 46556, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, 06520-8103, USA
- PTC Therapeutics Inc, South Plainfield, NJ, 07080, USA
| | - Gayathri N. Silva
- Department of Chemistry, University of Colombo, Colombo, Sri Lanka
- Corresponding author.
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Uridine diphosphate N-acetylglucosamine orchestrates the interaction of GlmR with either YvcJ or GlmS in Bacillus subtilis. Sci Rep 2020; 10:15938. [PMID: 32994436 PMCID: PMC7525490 DOI: 10.1038/s41598-020-72854-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/05/2020] [Indexed: 02/07/2023] Open
Abstract
In bacteria, glucosamine-6-phosphate (GlcN6P) synthase, GlmS, is an enzyme required for the synthesis of Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), a precursor of peptidoglycan. In Bacillus subtilis, an UDP-GlcNAc binding protein, GlmR (formerly YvcK), essential for growth on non-glycolytic carbon sources, has been proposed to stimulate GlmS activity; this activation could be antagonized by UDP-GlcNAc. Using purified proteins, we demonstrate that GlmR directly stimulates GlmS activity and the presence of UDP-GlcNAc (at concentrations above 0.1 mM) prevents this regulation. We also showed that YvcJ, whose gene is associated with yvcK (glmR), interacts with GlmR in an UDP-GlcNAc dependent manner. Strains producing GlmR variants unable to interact with YvcJ show decreased transformation efficiency similar to that of a yvcJ null mutant. We therefore propose that, depending on the intracellular concentration of UDP-GlcNAc, GlmR interacts with either YvcJ or GlmS. When UDP-GlcNAc concentration is high, this UDP-sugar binds to YvcJ and to GlmR, blocking the stimulation of GlmS activity and driving the interaction between GlmR and YvcJ to probably regulate the cellular role of the latter. When the UDP-GlcNAc level is low, GlmR does not interact with YvcJ and thus does not regulate its cellular role but interacts with GlmS to stimulate its activity.
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6
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Coussement P, Bauwens D, Peters G, Maertens J, De Mey M. Mapping and refactoring pathway control through metabolic and protein engineering: The hexosamine biosynthesis pathway. Biotechnol Adv 2020; 40:107512. [DOI: 10.1016/j.biotechadv.2020.107512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/07/2019] [Accepted: 09/30/2019] [Indexed: 01/14/2023]
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7
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A quasi-integral controller for adaptation of genetic modules to variable ribosome demand. Nat Commun 2018; 9:5415. [PMID: 30575748 PMCID: PMC6303309 DOI: 10.1038/s41467-018-07899-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 12/03/2018] [Indexed: 01/25/2023] Open
Abstract
The behavior of genetic circuits is often poorly predictable. A gene’s expression level is not only determined by the intended regulators, but also affected by changes in ribosome availability imparted by expression of other genes. Here we design a quasi-integral biomolecular feedback controller that enables the expression level of any gene of interest (GOI) to adapt to changes in available ribosomes. The feedback is implemented through a synthetic small RNA (sRNA) that silences the GOI’s mRNA, and uses orthogonal extracytoplasmic function (ECF) sigma factor to sense the GOI’s translation and to actuate sRNA transcription. Without the controller, the expression level of the GOI is reduced by 50% when a resource competitor is activated. With the controller, by contrast, gene expression level is practically unaffected by the competitor. This feedback controller allows adaptation of genetic modules to variable ribosome demand and thus aids modular construction of complicated circuits. Competition for shared cellular resources often renders genetic circuits poorly predictable. Here the authors design a biomolecular quasi-integral controller that allows gene expression to adapt to variable demand in translation resources.
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Knittel V, Vollmer I, Volk M, Dersch P. Discovering RNA-Based Regulatory Systems for Yersinia Virulence. Front Cell Infect Microbiol 2018; 8:378. [PMID: 30460205 PMCID: PMC6232918 DOI: 10.3389/fcimb.2018.00378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/05/2018] [Indexed: 12/26/2022] Open
Abstract
The genus Yersinia includes three human pathogenic species, Yersinia pestis, the causative agent of the bubonic and pneumonic plague, and enteric pathogens Y. enterocolitica and Y. pseudotuberculosis that cause a number of gut-associated diseases. Over the past years a large repertoire of RNA-based regulatory systems has been discovered in these pathogens using different RNA-seq based approaches. Among them are several conserved or species-specific RNA-binding proteins, regulatory and sensory RNAs as well as various RNA-degrading enzymes. Many of them were shown to control the expression of important virulence-relevant factors and have a very strong impact on Yersinia virulence. The precise targets, the molecular mechanism and their role for Yersinia pathogenicity is only known for a small subset of identified genus- or species-specific RNA-based control elements. However, the ongoing development of new RNA-seq based methods and data analysis methods to investigate the synthesis, composition, translation, decay, and modification of RNAs in the bacterial cell will help us to generate a more comprehensive view of Yersinia RNA biology in the near future.
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Affiliation(s)
- Vanessa Knittel
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Ines Vollmer
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Marcel Volk
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Petra Dersch
- Department of Molecular Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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9
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Durica-Mitic S, Göpel Y, Görke B. Carbohydrate Utilization in Bacteria: Making the Most Out of Sugars with the Help of Small Regulatory RNAs. Microbiol Spectr 2018; 6. [PMID: 29573258 DOI: 10.1128/microbiolspec.rwr-0013-2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Indexed: 12/11/2022] Open
Abstract
Survival of bacteria in ever-changing habitats with fluctuating nutrient supplies requires rapid adaptation of their metabolic capabilities. To this end, carbohydrate metabolism is governed by complex regulatory networks including posttranscriptional mechanisms that involve small regulatory RNAs (sRNAs) and RNA-binding proteins. sRNAs limit the response to substrate availability and set the threshold or time required for induction and repression of carbohydrate utilization systems. Carbon catabolite repression (CCR) also involves sRNAs. In Enterobacteriaceae, sRNA Spot 42 cooperates with the transcriptional regulator cyclic AMP (cAMP)-receptor protein (CRP) to repress secondary carbohydrate utilization genes when a preferred sugar is consumed. In pseudomonads, CCR operates entirely at the posttranscriptional level, involving RNA-binding protein Hfq and decoy sRNA CrcZ. Moreover, sRNAs coordinate fluxes through central carbohydrate metabolic pathways with carbohydrate availability. In Gram-negative bacteria, the interplay between RNA-binding protein CsrA and its cognate sRNAs regulates glycolysis and gluconeogenesis in response to signals derived from metabolism. Spot 42 and cAMP-CRP jointly downregulate tricarboxylic acid cycle activity when glycolytic carbon sources are ample. In addition, bacteria use sRNAs to reprogram carbohydrate metabolism in response to anaerobiosis and iron limitation. Finally, sRNAs also provide homeostasis of essential anabolic pathways, as exemplified by the hexosamine pathway providing cell envelope precursors. In this review, we discuss the manifold roles of bacterial sRNAs in regulation of carbon source uptake and utilization, substrate prioritization, and metabolism.
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Affiliation(s)
- Svetlana Durica-Mitic
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Yvonne Göpel
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
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10
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Leistra AN, Amador P, Buvanendiran A, Moon-Walker A, Contreras LM. Rational Modular RNA Engineering Based on In Vivo Profiling of Structural Accessibility. ACS Synth Biol 2017; 6:2228-2240. [PMID: 28796489 DOI: 10.1021/acssynbio.7b00185] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Bacterial small RNAs (sRNAs) have been established as powerful parts for controlling gene expression. However, development and application of engineered sRNAs has primarily focused on regulating novel synthetic targets. In this work, we demonstrate a rational modular RNA engineering approach that uses in vivo structural accessibility measurements to tune the regulatory activity of a multisubstrate sRNA for differential control of its native target network. Employing the CsrB global sRNA regulator as a model system, we use published in vivo structural accessibility data to infer the contribution of its local structures (substructures) to function and select a subset for engineering. We then modularly recombine the selected substructures, differentially representing those of presumed high or low functional contribution, to build a library of 21 CsrB variants. Using fluorescent translational reporter assays, we demonstrate that the CsrB variants achieve a 5-fold gradient of control of well-characterized Csr network targets. Interestingly, results suggest that less conserved local structures within long, multisubstrate sRNAs may represent better targets for rational engineering than their well-conserved counterparts. Lastly, mapping the impact of sRNA variants on a signature Csr network phenotype indicates the potential of this approach for tuning the activity of global sRNA regulators in the context of metabolic engineering applications.
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Affiliation(s)
- Abigail N. Leistra
- McKetta
Department of Chemical Engineering, University of Texas at Austin, 200
E. Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
| | - Paul Amador
- Microbiology
Graduate Program, University of Texas at Austin, 100 E. 24th Street
Stop A6500, Austin, Texas 78712, United States
| | - Aishwarya Buvanendiran
- Biological
Sciences Program College of Natural Sciences, University of Texas at Austin, 120 Inner Campus Drive Stop G2500, Austin, Texas 78712, United States
| | - Alex Moon-Walker
- Biological
Sciences Program College of Natural Sciences, University of Texas at Austin, 120 Inner Campus Drive Stop G2500, Austin, Texas 78712, United States
| | - Lydia M. Contreras
- McKetta
Department of Chemical Engineering, University of Texas at Austin, 200
E. Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
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11
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Bhatt S, Jenkins V, Mason E, Muche S. The Small Regulatory RNA Spot42 Inhibits Indole Biosynthesis to Negatively Regulate the Locus of Enterocyte Effacement of Enteropathogenic Escherichia coli. Microorganisms 2017; 5:microorganisms5040078. [PMID: 29194362 PMCID: PMC5748587 DOI: 10.3390/microorganisms5040078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 11/28/2017] [Accepted: 11/28/2017] [Indexed: 12/17/2022] Open
Abstract
The locus of enterocyte effacement is necessary for enteropathogenic Escherichia coli (EPEC) to form attaching and effacing (A/E) lesions. A/E lesions are characterized by intimate bacterial adherence to intestinal cells and destruction of microvilli, which leads to diarrhea. Therefore, studies interrogating the regulation of the locus of enterocyte effacement (LEE) are critical for understanding the molecular epidemiology of EPEC infections and developing interventional strategies. Hitherto, most studies have centered on protein-based regulators, whereas the role of small regulatory RNAs remains underappreciated. Previously, we identified the first sRNAs—MgrR, RyhB, and McaS—that regulate the LEE of EPEC. This study was undertaken to identify additional sRNAs that impact the LEE. Our results suggest that the catabolite-responsive sRNA, Spot42, indirectly controls the LEE by inhibiting synthesis of its inducer, indole. Spot42 base-pairs with the tnaCAB mRNA and presumably destabilizes the transcript, thereby preventing expression of the regulatory and structural proteins that are involved in the import and hydrolysis of tryptophan into indole. The absence of intracellular indole leads to reduced transcription of the LEE1-encoded master transcriptional activator Ler, thereby maintaining the LEE in its silenced state and delaying A/E lesion morphogenesis. Our results highlight the importance of riboregulators that synchronize metabolic and virulence pathways in bacterial infection.
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Affiliation(s)
- Shantanu Bhatt
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA.
| | - Valerie Jenkins
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA.
- Department of Chemistry, Saint Joseph's University, Philadelphia, PA 19131, USA.
| | - Elisabeth Mason
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA.
| | - Sarah Muche
- Department of Biology, Saint Joseph's University, Philadelphia, PA 19131, USA.
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12
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Matos RG, Casinhas J, Bárria C, dos Santos RF, Silva IJ, Arraiano CM. The Role of Ribonucleases and sRNAs in the Virulence of Foodborne Pathogens. Front Microbiol 2017; 8:910. [PMID: 28579982 PMCID: PMC5437115 DOI: 10.3389/fmicb.2017.00910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/04/2017] [Indexed: 12/02/2022] Open
Abstract
Contaminated food is the source of many severe infections in humans. Recent advances in food science have discovered new foodborne pathogens and progressed in characterizing their biology, life cycle, and infection processes. All this knowledge has been contributing to prevent food contamination, and to develop new therapeutics to treat the infections caused by these pathogens. RNA metabolism is a crucial biological process and has an enormous potential to offer new strategies to fight foodborne pathogens. In this review, we will summarize what is known about the role of bacterial ribonucleases and sRNAs in the virulence of several foodborne pathogens and how can we use that knowledge to prevent infection.
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Affiliation(s)
- Rute G. Matos
- Control of Gene Expression Laboratory, Instituto de Tecnologia Química e Biológica António Xavier (ITQB NOVA), Universidade NOVA de LisboaOeiras, Portugal
| | | | | | | | | | - Cecília M. Arraiano
- Control of Gene Expression Laboratory, Instituto de Tecnologia Química e Biológica António Xavier (ITQB NOVA), Universidade NOVA de LisboaOeiras, Portugal
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13
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Sugar Allocation to Metabolic Pathways is Tightly Regulated and Affects the Virulence of Streptococcus mutans. Genes (Basel) 2016; 8:genes8010011. [PMID: 28036052 PMCID: PMC5295006 DOI: 10.3390/genes8010011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/14/2016] [Accepted: 12/21/2016] [Indexed: 02/03/2023] Open
Abstract
Bacteria take up and metabolize sugar as a carbohydrate source for survival. Most bacteria can utilize many sugars, including glucose, sucrose, and galactose, as well as amino sugars, such as glucosamine and N-acetylglucosamine. After entering the cytoplasm, the sugars are mainly allocated to the glycolysis pathway (energy production) and to various bacterial component biosynthesis pathways, including the cell wall, nucleic acids and amino acids. Sugars are also utilized to produce several virulence factors, such as capsule and lipoteichoic acid. Glutamine-fructose-6-phosphate aminotransferase (GlmS) and glucosamine-6-phosphate deaminase (NagB) have crucial roles in sugar distribution to the glycolysis pathway and to cell wall biosynthesis. In Streptococcus mutans, a cariogenic pathogen, the expression levels of glmS and nagB are coordinately regulated in response to the presence or absence of amino sugars. In addition, the disruption of this regulation affects the virulence of S. mutans. The expression of nagB and glmS is regulated by NagR in S. mutans, but the precise mechanism underlying glmS regulation is not clear. In Staphylococcus aureus and Bacillus subtilis, the mRNA of glmS has ribozyme activity and undergoes self-degradation at the mRNA level. However, there is no ribozyme activity region on glmS mRNA in S. mutans. In this review article, we summarize the sugar distribution, particularly the coordinated regulation of GlmS and NagB expression, and its relationship with the virulence of S. mutans.
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14
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Yoo W, Yoon H, Seok YJ, Lee CR, Lee HH, Ryu S. Fine-tuning of amino sugar homeostasis by EIIA(Ntr) in Salmonella Typhimurium. Sci Rep 2016; 6:33055. [PMID: 27628932 PMCID: PMC5024086 DOI: 10.1038/srep33055] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
The nitrogen-metabolic phosphotransferase system, PTS(Ntr), consists of the enzymes I(Ntr), NPr and IIA(Ntr) that are encoded by ptsP, ptsO, and ptsN, respectively. Due to the proximity of ptsO and ptsN to rpoN, the PTS(Ntr) system has been postulated to be closely related with nitrogen metabolism. To define the correlation between PTS(Ntr) and nitrogen metabolism, we performed ligand fishing with EIIA(Ntr) as a bait and revealed that D-glucosamine-6-phosphate synthase (GlmS) directly interacted with EIIA(Ntr). GlmS, which converts D-fructose-6-phosphate (Fru6P) into D-glucosamine-6-phosphate (GlcN6P), is a key enzyme producing amino sugars through glutamine hydrolysis. Amino sugar is an essential structural building block for bacterial peptidoglycan and LPS. We further verified that EIIA(Ntr) inhibited GlmS activity by direct interaction in a phosphorylation-state-dependent manner. EIIA(Ntr) was dephosphorylated in response to excessive nitrogen sources and was rapidly degraded by Lon protease upon amino sugar depletion. The regulation of GlmS activity by EIIA(Ntr) and the modulation of glmS translation by RapZ suggest that the genes comprising the rpoN operon play a key role in maintaining amino sugar homeostasis in response to nitrogen availability and the amino sugar concentration in the bacterial cytoplasm.
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Affiliation(s)
- Woongjae Yoo
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Korea
| | - Hyunjin Yoon
- Department of Molecular Science and Technology, Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon 16499, Korea
| | - Yeong-Jae Seok
- Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 08826, Korea
| | - Chang-Ro Lee
- Department of Biological Sciences, Myongji University, Yongin, Gyeonggido 17058, Republic of Korea
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Korea
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, and Center for Food and Bioconvergence, Seoul National University, Seoul 08826, Korea
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15
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Lu P, Wang Y, Zhang Y, Hu Y, Thompson KM, Chen S. RpoS-dependent sRNA RgsA regulates Fis and AcpP in Pseudomonas aeruginosa. Mol Microbiol 2016; 102:244-259. [PMID: 27381272 DOI: 10.1111/mmi.13458] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2016] [Indexed: 12/01/2022]
Abstract
RgsA is a phylogenetically conserved small regulatory RNA (sRNA) in Pseudomonas species. This sRNA has been shown to be directly controlled by the major stationary phase and stress sigma factor σS (RpoS), and also indirectly regulated by the GacS/GacA two-component system. However, the role and the regulatory targets of this sRNA remain unclear. Here, two direct regulatory targets of RgsA, the mRNAs coding for the global transcriptional regulator Fis and the acyl carrier protein AcpP, were identified in P. aeruginosa. RgsA downregulates the synthesis of Fis and AcpP by base-pairing, and this regulation requires the RNA chaperone protein Hfq. Alignment of RgsA homologs in Pseudomonas revealed a conserved core region, which is strictly required for RgsA target recognition. Specifically, RgsA inhibits fis expression via an 11 + 11 bp RNA duplex, whereas this interaction region is not sufficient for repression and the 35 nt downstream region is also required. Interestingly, two functional start codons initiate fis mRNA translation and both are repressed by RgsA. Furthermore, deletion of rgsA significantly increased swarming motility in P. aeruginosa. Together, this study suggests a novel regulatory role of sRNA in which the versatile transcriptional regulator Fis and the stress regulator RpoS are connected by RgsA.
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Affiliation(s)
- Pei Lu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yifei Wang
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yong Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yangbo Hu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University, Washington, DC, 20059, USA
| | - 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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16
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Mechanisms of Evolutionary Innovation Point to Genetic Control Logic as the Key Difference Between Prokaryotes and Eukaryotes. J Mol Evol 2015. [PMID: 26208881 DOI: 10.1007/s00239-015-9688-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The evolution of life from the simplest, original form to complex, intelligent animal life occurred through a number of key innovations. Here we present a new tool to analyze these key innovations by proposing that the process of evolutionary innovation may follow one of three underlying processes, namely a Random Walk, a Critical Path, or a Many Paths process, and in some instances may also constitute a "Pull-up the Ladder" event. Our analysis is based on the occurrence of function in modern biology, rather than specific structure or mechanism. A function in modern biology may be classified in this way either on the basis of its evolution or the basis of its modern mechanism. Characterizing key innovations in this way helps identify the likelihood that an innovation could arise. In this paper, we describe the classification, and methods to classify functional features of modern organisms into these three classes based on the analysis of how a function is implemented in modern biology. We present the application of our categorization to the evolution of eukaryotic gene control. We use this approach to support the argument that there are few, and possibly no basic chemical differences between the functional constituents of the machinery of gene control between eukaryotes, bacteria and archaea. This suggests that the difference between eukaryotes and prokaryotes that allows the former to develop the complex genetic architecture seen in animals and plants is something other than their chemistry. We tentatively identify the difference as a difference in control logic, that prokaryotic genes are by default 'on' and eukaryotic genes are by default 'off.' The Many Paths evolutionary process suggests that, from a 'default off' starting point, the evolution of the genetic complexity of higher eukaryotes is a high probability event.
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17
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Patenge N, Pappesch R, Khani A, Kreikemeyer B. Genome-wide analyses of small non-coding RNAs in streptococci. Front Genet 2015; 6:189. [PMID: 26042151 PMCID: PMC4438229 DOI: 10.3389/fgene.2015.00189] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/08/2015] [Indexed: 01/01/2023] Open
Abstract
Streptococci represent a diverse group of Gram-positive bacteria, which colonize a wide range of hosts among animals and humans. Streptococcal species occur as commensal as well as pathogenic organisms. Many of the pathogenic species can cause severe, invasive infections in their hosts leading to a high morbidity and mortality. The consequence is a tremendous suffering on the part of men and livestock besides the significant financial burden in the agricultural and healthcare sectors. An environmentally stimulated and tightly controlled expression of virulence factor genes is of fundamental importance for streptococcal pathogenicity. Bacterial small non-coding RNAs (sRNAs) modulate the expression of genes involved in stress response, sugar metabolism, surface composition, and other properties that are related to bacterial virulence. Even though the regulatory character is shared by this class of RNAs, variation on the molecular level results in a high diversity of functional mechanisms. The knowledge about the role of sRNAs in streptococci is still limited, but in recent years, genome-wide screens for sRNAs have been conducted in an increasing number of species. Bioinformatics prediction approaches have been employed as well as expression analyses by classical array techniques or next generation sequencing. This review will give an overview of whole genome screens for sRNAs in streptococci with a focus on describing the different methods and comparing their outcome considering sRNA conservation among species, functional similarities, and relevance for streptococcal infection.
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Affiliation(s)
- Nadja Patenge
- Institute of Medical Microbiology, Virology, Hygiene and Bacteriology, Rostock University Medical Center Rostock, Germany
| | - Roberto Pappesch
- Institute of Medical Microbiology, Virology, Hygiene and Bacteriology, Rostock University Medical Center Rostock, Germany
| | - Afsaneh Khani
- Institute of Medical Microbiology, Virology, Hygiene and Bacteriology, Rostock University Medical Center Rostock, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology, Hygiene and Bacteriology, Rostock University Medical Center Rostock, Germany
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18
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19
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Moye ZD, Zeng L, Burne RA. Fueling the caries process: carbohydrate metabolism and gene regulation by Streptococcus mutans. J Oral Microbiol 2014; 6:24878. [PMID: 25317251 PMCID: PMC4157138 DOI: 10.3402/jom.v6.24878] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 11/17/2022] Open
Abstract
The nature of the oral cavity and host behaviors has mandated that the oral microbiota evolve mechanisms for coping with environmental fluctuations, especially changes in the type and availability of carbohydrates. In the case of human dental caries, the presence of excess carbohydrates is often responsible for altering the local environment to be more favorable for species associated with the initiation and progression of disease, including Streptococcus mutans. Some of the earliest endeavors to understand how cariogenic species respond to environmental perturbations were carried out using chemostat cultivation, which provides fine control over culture conditions and bacterial behaviors. The development of genome-scale methodologies has allowed for the combination of sophisticated cultivation technologies with genome-level analysis to more thoroughly probe how bacterial pathogens respond to environmental stimuli. Recent investigations in S. mutans and other closely related streptococci have begun to reveal that carbohydrate metabolism can drastically impact pathogenic potential and highlight the important influence that nutrient acquisition has on the success of pathogens; inside and outside of the oral cavity. Collectively, research into pathogenic streptococci, which have evolved in close association with the human host, has begun to unveil the essential nature of careful orchestration of carbohydrate acquisition and catabolism to allow the organisms to persist and, when conditions allow, initiate or worsen disease.
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Affiliation(s)
- Zachary D Moye
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Lin Zeng
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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20
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Uptake and metabolism of N-acetylglucosamine and glucosamine by Streptococcus mutans. Appl Environ Microbiol 2014; 80:5053-67. [PMID: 24928869 DOI: 10.1128/aem.00820-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucosamine and N-acetylglucosamine are among the most abundant sugars on the planet, and their introduction into the oral cavity via the diet and host secretions, and through bacterial biosynthesis, provides oral biofilm bacteria with a source of carbon, nitrogen, and energy. In this study, we demonstrated that the dental caries pathogen Streptococcus mutans possesses an inducible system for the metabolism of N-acetylglucosamine and glucosamine. These amino sugars are transported by the phosphoenolpyruvate:sugar phosphotransferase system (PTS), with the glucose/mannose enzyme II permease encoded by manLMN playing a dominant role. Additionally, a previously uncharacterized gene product encoded downstream of the manLMN operon, ManO, was shown to influence the efficiency of uptake and growth on N-acetylglucosamine and, to a lesser extent, glucosamine. A transcriptional regulator, designated NagR, was able to bind the promoter regions in vitro, and repress the expression in vivo, of the nagA and nagB genes, encoding N-acetylglucosamine-6-phosphate deacetylase and glucosamine-6-phosphate deaminase, respectively. The binding activity of NagR could be inhibited by glucosamine-6-phosphate in vitro. Importantly, in contrast to the case with certain other Firmicutes, the gene for de novo synthesis of glucosamine-6-phosphate in S. mutans, glmS, was also shown to be regulated by NagR, and NagR could bind the glmS promoter region in vitro. Finally, metabolism of these amino sugars by S. mutans resulted in the production of significant quantities of ammonia, which can neutralize cytoplasmic pH and increase acid tolerance, thus contributing to enhanced persistence and pathogenic potential.
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22
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Lu P, Zhang Y, Hu Y, Francis MS, Chen S. A cis-encoded sRNA controls the expression of fabH2 in Yersinia. FEBS Lett 2014; 588:1961-6. [PMID: 24735725 DOI: 10.1016/j.febslet.2014.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/10/2014] [Accepted: 04/03/2014] [Indexed: 11/16/2022]
Abstract
YsrH is a novel cis-encoded sRNA located on the opposite strand to fabH2, which is essential for fatty acid biosynthesis in bacteria. In this study, YsrH-mediated regulation of fabH2 expression was investigated in Yersinia pseudotuberculosis. Constitutive and inducible over-expression of YsrH decreased the mRNA level of fabH2, while expression of downstream fabD and fabG remained unaffected. Polynucleotide phosphorylase (PNPase) also played an important role in this regulation process by mediating YsrH decay in the exponential phase. Thus, our data defines a cis-encoded sRNA that regulates fatty acid synthesis via a regulatory mechanism also involving PNPase.
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Affiliation(s)
- Pei Lu
- Key Laboratory of Etiology and Biosafety for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Yong Zhang
- Key Laboratory of Etiology and Biosafety for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Yangbo Hu
- Key Laboratory of Etiology and Biosafety for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Matthew S Francis
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå, Sweden
| | - Shiyun Chen
- Key Laboratory of Etiology and Biosafety for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
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23
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Göpel Y, Khan MA, Görke B. Ménage à trois: post-transcriptional control of the key enzyme for cell envelope synthesis by a base-pairing small RNA, an RNase adaptor protein, and a small RNA mimic. RNA Biol 2014; 11:433-42. [PMID: 24667238 PMCID: PMC4152352 DOI: 10.4161/rna.28301] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In Escherichia coli, small RNAs GlmY and GlmZ feedback control synthesis of glucosamine-6-phosphate (GlcN6P) synthase GlmS, a key enzyme required for synthesis of the cell envelope. Both small RNAs are highly similar, but only GlmZ is able to activate the glmS mRNA by base-pairing. Abundance of GlmZ is controlled at the level of decay by RNase adaptor protein RapZ. RapZ binds and targets GlmZ to degradation by RNase E via protein–protein interaction. GlmY activates glmS indirectly by protecting GlmZ from degradation. Upon GlcN6P depletion, GlmY accumulates and sequesters RapZ in an RNA mimicry mechanism, thus acting as an anti-adaptor. As a result, this regulatory circuit adjusts synthesis of GlmS to the level of its enzymatic product, thereby mediating GlcN6P homeostasis. The interplay of RNase adaptor proteins and anti-adaptors provides an elegant means how globally acting RNases can be re-programmed to cleave a specific transcript in response to a cognate stimulus.
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Affiliation(s)
- Yvonne Göpel
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
| | - Muna A Khan
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
| | - Boris Görke
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
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24
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Nguyen AN, Jacq A. Small RNAs in the Vibrionaceae: an ocean still to be explored. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:381-92. [PMID: 24458378 DOI: 10.1002/wrna.1218] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 12/13/2013] [Accepted: 12/16/2013] [Indexed: 11/09/2022]
Abstract
In bacteria, the discovery of noncoding small RNAs (sRNAs) as modulators of gene expression in response to environmental signals has brought new insights into bacterial gene regulation, including control of pathogenicity. The Vibrionaceae constitute a family of marine bacteria of which many are responsible for infections affecting not only humans, such as Vibrio cholerae but also fish and marine invertebrates, representing the major cause of mortality in farmed marine species. They are able to colonize many habitats, existing as planktonic forms, in biofilms or associated with various hosts. This high adaptability is linked to their capacity to generate genetic diversity, in part through lateral gene transfer, but also by varying gene expression control. In the recent years, several major studies have illustrated the importance of small regulatory sRNAs in the Vibrionaceae for the control of pathogenicity and adaptation to environment and nutrient sources such as chitin, especially in V. cholerae and Vibrio harveyi. The existence of a complex regulatory network controlled by quorum sensing has been demonstrated in which sRNAs play central roles. This review covers major advances made in the discovery and elucidation of functions of Vibrionaceae sRNAs within the last 10 years.
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Affiliation(s)
- An Ngoc Nguyen
- Institut de Génétique et Microbiologie, UMR 8621 CNRS-Université Paris-Sud, 91405 Orsay Cedex, France
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25
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Carlson-Banning KM, Chou A, Liu Z, Hamill RJ, Song Y, Zechiedrich L. Toward repurposing ciclopirox as an antibiotic against drug-resistant Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae. PLoS One 2013; 8:e69646. [PMID: 23936064 PMCID: PMC3720592 DOI: 10.1371/journal.pone.0069646] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/12/2013] [Indexed: 12/27/2022] Open
Abstract
Antibiotic-resistant infections caused by gram-negative bacteria are a major healthcare concern. Repurposing drugs circumvents the time and money limitations associated with developing new antimicrobial agents needed to combat these antibiotic-resistant infections. Here we identified the off-patent antifungal agent, ciclopirox, as a candidate to repurpose for antibiotic use. To test the efficacy of ciclopirox against antibiotic-resistant pathogens, we used a curated collection of Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae clinical isolates that are representative of known antibiotic resistance phenotypes. We found that ciclopirox, at 5–15 µg/ml concentrations, inhibited bacterial growth regardless of the antibiotic resistance status. At these same concentrations, ciclopirox reduced growth of Pseudomonas aeruginosa clinical isolates, but some of these pathogens required higher ciclopirox concentrations to completely block growth. To determine how ciclopirox inhibits bacterial growth, we performed an overexpression screen in E. coli. This screen revealed that galE, which encodes UDP-glucose 4-epimerase, rescued bacterial growth at otherwise restrictive ciclopirox concentrations. We found that ciclopirox does not inhibit epimerization of UDP-galactose by purified E. coli GalE; however, ΔgalU, ΔgalE, ΔrfaI, or ΔrfaB mutant strains all have lower ciclopirox minimum inhibitory concentrations than the parent strain. The galU, galE, rfaI, and rfaB genes all encode enzymes that use UDP-galactose or UDP-glucose for galactose metabolism and lipopolysaccharide (LPS) biosynthesis. Indeed, we found that ciclopirox altered LPS composition of an E. coli clinical isolate. Taken together, our data demonstrate that ciclopirox affects galactose metabolism and LPS biosynthesis, two pathways important for bacterial growth and virulence. The lack of any reported fungal resistance to ciclopirox in over twenty years of use in the clinic, its excellent safety profiles, novel target(s), and efficacy, make ciclopirox a promising potential antimicrobial agent to use against multidrug-resistant problematic gram-negative pathogens.
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Affiliation(s)
- Kimberly M. Carlson-Banning
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrew Chou
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Zhen Liu
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard J. Hamill
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Michael E. DeBakey VA Medical Center, Houston, Texas, United States of America
| | - Yongcheng Song
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lynn Zechiedrich
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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26
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Fu Y, Deiorio-Haggar K, Anthony J, Meyer MM. Most RNAs regulating ribosomal protein biosynthesis in Escherichia coli are narrowly distributed to Gammaproteobacteria. Nucleic Acids Res 2013; 41:3491-503. [PMID: 23396277 PMCID: PMC3616713 DOI: 10.1093/nar/gkt055] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/02/2013] [Accepted: 01/10/2013] [Indexed: 01/30/2023] Open
Abstract
In Escherichia coli, 12 distinct RNA structures within the transcripts encoding ribosomal proteins interact with specific ribosomal proteins to allow autogenous regulation of expression from large multi-gene operons, thus coordinating ribosomal protein biosynthesis across multiple operons. However, these RNA structures are typically not represented in the RNA Families Database or annotated in genomic sequences databases, and their phylogenetic distribution is largely unknown. To investigate the extent to which these RNA structures are conserved across eubacterial phyla, we created multiple sequence alignments representing 10 of these messenger RNA (mRNA) structures in E. coli. We find that while three RNA structures are widely distributed across many phyla of bacteria, seven of the RNAs are narrowly distributed to a few orders of Gammaproteobacteria. To experimentally validate our computational predictions, we biochemically confirmed dual L1-binding sites identified in many Firmicute species. This work reveals that RNA-based regulation of ribosomal protein biosynthesis is used in nearly all eubacterial phyla, but the specific RNA structures that regulate ribosomal protein biosynthesis in E. coli are narrowly distributed. These results highlight the limits of our knowledge regarding ribosomal protein biosynthesis regulation outside of E. coli, and the potential for alternative RNA structures responsible for regulating ribosomal proteins in other eubacteria.
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Affiliation(s)
| | | | | | - Michelle M. Meyer
- Department of Biology, Boston College, 140 Commonwealth Ave. Chestnut Hill, MA 02467, USA
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27
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Resch M, Göpel Y, Görke B, Ficner R. Crystallization and preliminary X-ray diffraction analysis of YhbJ from Escherichia coli, a key protein involved in the GlmYZ sRNA regulatory cascade. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:109-14. [PMID: 23385747 PMCID: PMC3564608 DOI: 10.1107/s1744309112048622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/26/2012] [Indexed: 11/10/2022]
Abstract
The protein YhbJ from Escherichia coli was previously reported to be involved in the regulation of glucosamine-6-phosphate synthase (GlmS) synthesis. YhbJ controls a regulatory cascade composed of the two small RNAs GlmY and GlmZ, which in turn regulate GlmS synthesis. For structural characterization, YhbJ was cloned, expressed and purified to homogeneity by Strep-tag affinity chromatography and size-exclusion chromatography. Multi-angle laser light-scattering analysis revealed its homotrimeric state in solution. The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 91.62, c = 352.82 Å for space group P321 and a = b = 92.72, c = 156.75 Å for one of the enantiomorphic space groups P3(1) or P3(2). Preliminary analysis of the diffraction data suggests the presence of approximately three to seven molecules per asymmetric unit. Owing to the lack of a suitable homologous model, structure determination by means of MIR and MAD methods is required.
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Affiliation(s)
- Marcus Resch
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Yvonne Göpel
- Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
| | - Boris Görke
- Abteilung für Allgemeine Mikrobiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
| | - Ralf Ficner
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
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28
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Gelderman G, Contreras LM. Discovery of posttranscriptional regulatory RNAs using next generation sequencing technologies. Methods Mol Biol 2013; 985:269-95. [PMID: 23417809 DOI: 10.1007/978-1-62703-299-5_14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Next generation sequencing (NGS) has revolutionized the way by which we engineer metabolism by radically altering the path to genome-wide inquiries. This is due to the fact that NGS approaches offer several powerful advantages over traditional methods that include the ability to fully sequence hundreds to thousands of genes in a single experiment and simultaneously detect homozygous and heterozygous deletions, alterations in gene copy number, insertions, translocations, and exome-wide substitutions that include "hot-spot mutations." This chapter describes the use of these technologies as a sequencing technique for transcriptome analysis and discovery of regulatory RNA elements in the context of three main platforms: Illumina HiSeq, 454 pyrosequencing, and SOLiD sequencing. Specifically, this chapter focuses on the use of Illumina HiSeq, since it is the most widely used platform for RNA discovery and transcriptome analysis. Regulatory RNAs have now been found in all branches of life. In bacteria, noncoding small RNAs (sRNAs) are involved in highly sophisticated regulatory circuits that include quorum sensing, carbon metabolism, stress responses, and virulence (Gorke and Vogel, Gene Dev 22:2914-2925, 2008; Gottesman, Trends Genet 21:399-404, 2005; Romby et al., Curr Opin Microbiol 9:229-236, 2006). Further characterization of the underlying regulation of gene expression remains poorly understood given that it is estimated that over 60% of all predicted genes remain hypothetical and the 5' and 3' untranslated regions are unknown for more than 90% of the genes (Siegel et al., Trends Parasitol 27:434-441, 2011). Importantly, manipulation of the posttranscriptional regulation that occurs at the level of RNA stability and export, trans-splicing, polyadenylation, protein translation, and protein stability via untranslated regions (Clayton, EMBO J 21:1881-1888, 2002; Haile and Papadopoulou, Curr Opin Microbiol 10:569-577, 2007) could be highly beneficial to metabolic engineering.
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Affiliation(s)
- Grant Gelderman
- Department of Chemical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA
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Maes A, Gracia C, Bréchemier D, Hamman P, Chatre E, Lemelle L, Bertin PN, Hajnsdorf E. Role of polyadenylation in regulation of the flagella cascade and motility in Escherichia coli. Biochimie 2012; 95:410-8. [PMID: 23123524 DOI: 10.1016/j.biochi.2012.10.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 10/15/2012] [Indexed: 12/15/2022]
Abstract
Polyadenylation is recognized as part of a surveillance machinery for eliminating defective RNA molecules in eukaryotes and prokaryotes. Escherichia coli strains, deficient in poly(A)polymerase I (PAP I), expressed less flagellin compared to wild-type strains. Because flagellin synthesis is a late step in the flagellar biosynthesis pathway, we assessed the role of PAP I in this cascade and in flagella function. Transcription of flhDC, fliA, and fliC was decreased in the PAP I mutant. These results provide evidence that polyadenylation positively controls the expression of genes belonging to the flagellar biosynthesis pathway and that this effect is mediated through the FlhDC master regulator. However, the downshift in flagella gene expression in the mutant strain did not provoke any noticeable defects in the synthesis of flagella, in biofilm formation and in swimming speed although there was a reduction in motility on soft agar. Our data support an alternative hypothesis that the reduced motility of the mutant resulted from an alteration of the cell membrane composition caused in part by the higher level of GlmS (Glucosamine-6P synthase) which accumulates in the mutant. In agreement with this hypothesis the mutant is more sensitive to hydrophobic agents and antibiotics and in particular to vancomycin. We propose that PAP I participates in the ability of the bacteria to adapt to and survive detrimental conditions by constantly monitoring and adjusting to its environment.
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Affiliation(s)
- Alexandre Maes
- CNRS UPR9073, associated with University Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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Patenge N, Billion A, Raasch P, Normann J, Wisniewska-Kucper A, Retey J, Boisguérin V, Hartsch T, Hain T, Kreikemeyer B. Identification of novel growth phase- and media-dependent small non-coding RNAs in Streptococcus pyogenes M49 using intergenic tiling arrays. BMC Genomics 2012; 13:550. [PMID: 23062031 PMCID: PMC3542284 DOI: 10.1186/1471-2164-13-550] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/10/2012] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Small non-coding RNAs (sRNAs) have attracted attention as a new class of gene regulators in both eukaryotes and bacteria. Genome-wide screening methods have been successfully applied in Gram-negative bacteria to identify sRNA regulators. Many sRNAs are well characterized, including their target mRNAs and mode of action. In comparison, little is known about sRNAs in Gram-positive pathogens. In this study, we identified novel sRNAs in the exclusively human pathogen Streptococcus pyogenes M49 (Group A Streptococcus, GAS M49), employing a whole genome intergenic tiling array approach. GAS is an important pathogen that causes diseases ranging from mild superficial infections of the skin and mucous membranes of the naso-pharynx, to severe toxic and invasive diseases. RESULTS We identified 55 putative sRNAs in GAS M49 that were expressed during growth. Of these, 42 were novel. Some of the newly-identified sRNAs belonged to one of the common non-coding RNA families described in the Rfam database. Comparison of the results of our screen with the outcome of two recently published bioinformatics tools showed a low level of overlap between putative sRNA genes. Previously, 40 potential sRNAs have been reported to be expressed in a GAS M1T1 serotype, as detected by a whole genome intergenic tiling array approach. Our screen detected 12 putative sRNA genes that were expressed in both strains. Twenty sRNA candidates appeared to be regulated in a medium-dependent fashion, while eight sRNA genes were regulated throughout growth in chemically defined medium. Expression of candidate genes was verified by reverse transcriptase-qPCR. For a subset of sRNAs, the transcriptional start was determined by 5' rapid amplification of cDNA ends-PCR (RACE-PCR) analysis. CONCLUSIONS In accord with the results of previous studies, we found little overlap between different screening methods, which underlines the fact that a comprehensive analysis of sRNAs expressed by a given organism requires the complementary use of different methods and the investigation of several environmental conditions. Despite a high conservation of sRNA genes within streptococci, the expression of sRNAs appears to be strain specific.
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Affiliation(s)
- Nadja Patenge
- Institute of Medical Microbiology and Hospital Hygiene, University of Rostock, Schillingallee 70, 18057, Rostock, Germany
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Vinuselvi P, Kim MK, Lee SK, Ghim CM. Rewiring carbon catabolite repression for microbial cell factory. BMB Rep 2012; 45:59-70. [PMID: 22360882 DOI: 10.5483/bmbrep.2012.45.2.59] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose- based biorefinery.
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Affiliation(s)
- Parisutham Vinuselvi
- School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
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Murina VN, Nikulin AD. RNA-binding Sm-like proteins of bacteria and archaea. similarity and difference in structure and function. BIOCHEMISTRY (MOSCOW) 2012; 76:1434-49. [PMID: 22339597 DOI: 10.1134/s0006297911130050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RNA-binding proteins play a significant role in many processes of RNA metabolism, such as splicing and processing, regulation of DNA transcription and RNA translation, etc. Among the great number of RNA-binding proteins, so-called RNA-chaperones occupy an individual niche; they were named for their ability to assist RNA molecules to gain their accurate native spatial structure. When binding with RNAs, they possess the capability of altering (melting) their secondary structure, thus providing a possibility for formation of necessary intramolecular contacts between individual RNA sites for proper folding. These proteins also have an additional helper function in RNA-RNA and RNA-protein interactions. Members of such class of the RNA-binding protein family are Sm and Sm-like proteins (Sm-Like, LSm). The presence of these proteins in bacteria, archaea, and eukaryotes emphasizes their biological significance. These proteins are now attractive for researchers because of their implication in many processes associated with RNAs in bacterial and archaeal cells. This review is focused on a comparison of architecture of bacterial and archaeal LSm proteins and their interaction with different RNA molecules.
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Affiliation(s)
- V N Murina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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Lu P, Zhang Y, Li L, Hu Y, Huang L, Li Y, Rayner S, Chen S. Small non-coding RNA SraG regulates the operon YPK_1206-1205 in Yersinia pseudotuberculosis. FEMS Microbiol Lett 2012; 331:37-43. [DOI: 10.1111/j.1574-6968.2012.02548.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 11/28/2022] Open
Affiliation(s)
| | - Yong Zhang
- Key Laboratory of Agricultural and Environmental Microbiology; Wuhan Institute of Virology; The Chinese Academy of Sciences; Wuhan; China
| | | | - Yangbo Hu
- Key Laboratory of Agricultural and Environmental Microbiology; Wuhan Institute of Virology; The Chinese Academy of Sciences; Wuhan; China
| | | | | | - Simon Rayner
- Key Laboratory of Agricultural and Environmental Microbiology; Wuhan Institute of Virology; The Chinese Academy of Sciences; Wuhan; China
| | - Shiyun Chen
- Key Laboratory of Agricultural and Environmental Microbiology; Wuhan Institute of Virology; The Chinese Academy of Sciences; Wuhan; China
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Babujee L, Apodaca J, Balakrishnan V, Liss P, Kiley PJ, Charkowski AO, Glasner JD, Perna NT. Evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria. BMC Genomics 2012; 13:110. [PMID: 22439737 PMCID: PMC3349551 DOI: 10.1186/1471-2164-13-110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 03/22/2012] [Indexed: 01/31/2023] Open
Abstract
Background Dickeya dadantii and Pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of O2 concentrations found in plant and natural environments. The transcriptional response to O2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including Escherichia coli and Salmonella enterica. Knowledge of the extent of conservation of the transcriptional response across orthologous genes in more distantly related species is useful to identify rates and patterns of regulon evolution. Evolutionary events such as loss and acquisition of genes by lateral transfer events along each evolutionary branch results in lineage-specific genes, some of which may have been subsequently incorporated into the O2-responsive stimulon. Here we present a comparison of transcriptional profiles measured using densely tiled oligonucleotide arrays for two phytopathogens, Dickeya dadantii 3937 and Pectobacterium atrosepticum SCRI1043, grown to mid-log phase in MOPS minimal medium (0.1% glucose) with and without O2. Results More than 7% of the genes of each phytopathogen are differentially expressed with greater than 3-fold changes under anaerobic conditions. In addition to anaerobic metabolism genes, the O2 responsive stimulon includes a variety of virulence and pathogenicity-genes. Few of these genes overlap with orthologous genes in the anaerobic stimulon of E. coli. We define these as the conserved core, in which the transcriptional pattern as well as genetic architecture are well preserved. This conserved core includes previously described anaerobic metabolic pathways such as fermentation. Other components of the anaerobic stimulon show variation in genetic content, genome architecture and regulation. Notably formate metabolism, nitrate/nitrite metabolism, and fermentative butanediol production, differ between E. coli and the phytopathogens. Surprisingly, the overlap of the anaerobic stimulon between the phytopathogens is also relatively small considering that they are closely related, occupy similar niches and employ similar strategies to cause disease. There are cases of interesting divergences in the pattern of transcription of genes between Dickeya and Pectobacterium for virulence-associated subsystems including the type VI secretion system (T6SS), suggesting that fine-tuning of the stimulon impacts interaction with plants or competing microbes. Conclusions The small number of genes (an even smaller number if we consider operons) comprising the conserved core transcriptional response to O2 limitation demonstrates the extent of regulatory divergence prevalent in the Enterobacteriaceae. Our orthology-driven comparative transcriptomics approach indicates that the adaptive response in the eneterobacteria is a result of interaction of core (regulators) and lineage-specific (structural and regulatory) genes. Our subsystems based approach reveals that similar phenotypic outcomes are sometimes achieved by each organism using different genes and regulatory strategies.
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Affiliation(s)
- Lavanya Babujee
- Biotechnology Center, University of Wisconsin-Madison, WI, USA
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Regulatory tasks of the phosphoenolpyruvate-phosphotransferase system of Pseudomonas putida in central carbon metabolism. mBio 2012; 3:mBio.00028-12. [PMID: 22434849 PMCID: PMC3312210 DOI: 10.1128/mbio.00028-12] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Two branches of the phosphoenolpyruvate-phosphotransferase system (PTS) operate in the soil bacterium Pseudomonas putida KT2440. One branch encompasses a complete set of enzymes for fructose intake (PTSFru), while the other (N-related PTS, or PTSNtr) controls various cellular functions unrelated to the transport of carbohydrates. The potential of these two systems for regulating central carbon catabolism has been investigated by measuring the metabolic fluxes of isogenic strains bearing nonpolar mutations in PTSFru or PTSNtr genes and grown on either fructose (a PTS substrate) or glucose, the transport of which is not governed by the PTS in this bacterium. The flow of carbon from each sugar was distinctly split between the Entner-Doudoroff, pentose phosphate, and Embden-Meyerhof-Parnas pathways in a ratio that was maintained in each of the PTS mutants examined. However, strains lacking PtsN (EIIANtr) displayed significantly higher fluxes in the reactions of the pyruvate shunt, which bypasses malate dehydrogenase in the TCA cycle. This was consistent with the increased activity of the malic enzyme and the pyruvate carboxylase found in the corresponding PTS mutants. Genetic evidence suggested that such a metabolic effect of PtsN required the transfer of high-energy phosphate through the system. The EIIANtr protein of the PTSNtr thus helps adjust central metabolic fluxes to satisfy the anabolic and energetic demands of the overall cell physiology. This study demonstrates that EIIANtr influences the biochemical reactions that deliver carbon between the upper and lower central metabolic domains for the consumption of sugars by P. putida. These findings indicate that the EIIANtr protein is a key player for orchestrating the fate of carbon in various physiological destinations in this bacterium. Additionally, these results highlight the importance of the posttranslational regulation of extant enzymatic complexes for increasing the robustness of the corresponding metabolic networks.
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Kawada-Matsuo M, Mazda Y, Oogai Y, Kajiya M, Kawai T, Yamada S, Miyawaki S, Oho T, Komatsuzawa H. GlmS and NagB regulate amino sugar metabolism in opposing directions and affect Streptococcus mutans virulence. PLoS One 2012; 7:e33382. [PMID: 22438919 PMCID: PMC3306399 DOI: 10.1371/journal.pone.0033382] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 02/14/2012] [Indexed: 11/18/2022] Open
Abstract
Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB) are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.
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Affiliation(s)
- Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yusuke Mazda
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Mikihito Kajiya
- Department of Immunology, The Forsyth Institute, Boston, Massachusetts, United States of America
| | - Toshihisa Kawai
- Department of Immunology, The Forsyth Institute, Boston, Massachusetts, United States of America
| | - Sakuo Yamada
- Department of Microbiology, Kawasaki Medical School, Okayama, Japan
- Department of Clinical Nutrition, Kawasaki Medical Welfare, Okayama, Japan
| | - Shouichi Miyawaki
- Department of Orthodontics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takahiko Oho
- Department of Preventive Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- * E-mail:
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Ortega AD, Gonzalo-Asensio J, García-del Portillo F. Dynamics of Salmonella small RNA expression in non-growing bacteria located inside eukaryotic cells. RNA Biol 2012; 9:469-88. [PMID: 22336761 DOI: 10.4161/rna.19317] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Small non-coding regulatory RNAs (sRNAs) have been studied in many bacterial pathogens during infection. However, few studies have focused on how intracellular pathogens modulate sRNA expression inside eukaryotic cells. Here, we monitored expression of all known sRNAs of Salmonella enterica serovar Typhimurium (S. Typhimurium) in bacteria located inside fibroblasts, a host cell type in which this pathogen restrains growth. sRNA sequences known in S. Typhimurium and Escherichia coli were searched in the genome of S. Typhimurium virulent strain SL1344, the subject of this study. Expression of 84 distinct sRNAs was compared in extra- and intracellular bacteria. Non-proliferating intracellular bacteria upregulated six sRNAs, including IsrA, IsrG, IstR-2, RyhB-1, RyhB-2 and RseX while repressed the expression of the sRNAs DsrA, GlmZ, IsrH-1, IsrI, SraL, SroC, SsrS(6S) and RydC. Interestingly, IsrH-1 was previously reported as an sRNA induced by S. Typhimurium inside macrophages. Kinetic analyses unraveled changing expression patterns for some sRNAs along the infection. InvR and T44 expression dropped after an initial induction phase while IstR-2 was induced exclusively at late infection times (> 6 h). Studies focused on the Salmonella-specific sRNA RyhB-2 revealed that intracellular bacteria use this sRNA to regulate negatively YeaQ, a cis-encoded protein of unknown function. RyhB-2, together with RyhB-1, contributes to attenuate intracellular bacterial growth. To our knowledge, these data represent the first comprehensive study of S. Typhimurium sRNA expression in intracellular bacteria and provide the first insights into sRNAs that may direct pathogen adaptation to a non-proliferative state inside the host cell.
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Affiliation(s)
- Alvaro D Ortega
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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Patenge N, Fiedler T, Kreikemeyer B. Common regulators of virulence in streptococci. Curr Top Microbiol Immunol 2012; 368:111-53. [PMID: 23242855 DOI: 10.1007/82_2012_295] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Streptococcal species are a diverse group of bacteria which can be found in animals and humans. Their interactions with host organisms can vary from commensal to pathogenic. Many of the pathogenic species are causative agents of severe, invasive infections in their hosts, accounting for a high burden of morbidity and mortality, associated with high economic costs in industry and health care. Among them, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, and Streptococcus suis are discussed here. An environmentally stimulated and tightly controlled expression of their virulence factors is of utmost importance for their pathogenic potential. Thus, the most universal and widespread regulators from the classes of stand-alone transcriptional regulators, two-component signal transduction systems (TCS), eukaryotic-like serine/threonine kinases, and small noncoding RNAs are the topic of this chapter. The regulatory levels are reviewed with respect to function, activity, and their role in pathogenesis. Understanding of and interfering with transcriptional regulation mechanisms and networks is a promising basis for the development of novel anti-infective therapies.
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Affiliation(s)
- Nadja Patenge
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Schillingallee 70, 18057 Rostock, Germany
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From conformational chaos to robust regulation: the structure and function of the multi-enzyme RNA degradosome. Q Rev Biophys 2011; 45:105-45. [DOI: 10.1017/s003358351100014x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractThe RNA degradosome is a massive multi-enzyme assembly that occupies a nexus in RNA metabolism and post-transcriptional control of gene expression inEscherichia coliand many other bacteria. Powering RNA turnover and quality control, the degradosome serves also as a machine for processing structured RNA precursors during their maturation. The capacity to switch between destructive and processing modes involves cooperation between degradosome components and is analogous to the process of RNA surveillance in other domains of life. Recruitment of components and cellular compartmentalisation of the degradosome are mediated through small recognition domains that punctuate a natively unstructured segment within a scaffolding core. Dynamic in conformation, variable in composition and non-essential under certain laboratory conditions, the degradosome has nonetheless been maintained throughout the evolution of many bacterial species, due most likely to its diverse contributions in global cellular regulation. We describe the role of the degradosome and its components in RNA decay pathways inE. coli, and we broadly compare these pathways in other bacteria as well as archaea and eukaryotes. We discuss the modular architecture and molecular evolution of the degradosome, its roles in RNA degradation, processing and quality control surveillance, and how its activity is regulated by non-coding RNA. Parallels are drawn with analogous machinery in organisms from all life domains. Finally, we conjecture on roles of the degradosome as a regulatory hub for complex cellular processes.
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The Vibrio cholerae mannitol transporter is regulated posttranscriptionally by the MtlS small regulatory RNA. J Bacteriol 2011; 194:598-606. [PMID: 22101846 DOI: 10.1128/jb.06153-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Vibrio cholerae continues to pose a health threat in many developing nations and regions of the world struck by natural disasters. It is a pathogen that rapidly adapts to aquatic environments and the human small intestine. Small regulatory RNAs (sRNAs) may contribute to this adaptability. Specifically, the mannitol operon sRNA (MtlS sRNA; previously designated the IGR7 sRNA) is transcribed antisense to the 5' untranslated region of the mtl operon, encoding the mannitol-specific phosphotransferase system. Mannitol is a six-carbon sugar alcohol that accumulates in the human small intestine, the primary site of V. cholerae colonization. To better understand the V. cholerae mtl operon at a molecular level, we investigated mtlA expression in the presence of various carbon sources and the role of the MtlS sRNA. We observed that MtlA protein is present only in cells grown on mannitol sugar, whereas MtlS sRNA is expressed during growth on all sugars other than mannitol. In contrast, mtlA mRNA is expressed in similar amounts regardless of the carbon source used for bacterial growth. These observations suggest that the regulation of MtlA protein expression is a posttranscriptional event. We further demonstrate that MtlS sRNA overexpression repressed MtlA synthesis without affecting the stability of the messenger and that this process is largely independent of Hfq. We propose a model in which, when carbon sources other than mannitol are present, MtlS sRNA is transcribed, base pairs with the 5' untranslated region of the mtlA mRNA, occluding the ribosome binding site, and inhibits the synthesis of the mannitol-specific phosphotransferase system.
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Richards GR, Vanderpool CK. Molecular call and response: the physiology of bacterial small RNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:525-31. [PMID: 21843668 DOI: 10.1016/j.bbagrm.2011.07.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 07/21/2011] [Accepted: 07/22/2011] [Indexed: 11/30/2022]
Abstract
The vital role of bacterial small RNAs (sRNAs) in cellular regulation is now well-established. Although many diverse mechanisms by which sRNAs bring about changes in gene expression have been thoroughly described, comparatively less is known about their biological roles and effects on cell physiology. Nevertheless, for some sRNAs, insight has been gained into the intricate regulatory interplay that is required to sense external environmental and internal metabolic cues and turn them into physiological outcomes. Here, we review examples of regulation by selected sRNAs, emphasizing signals and regulators required for sRNA expression, sRNA regulatory targets, and the resulting consequences for the cell. We highlight sRNAs involved in regulation of the processes of iron homeostasis (RyhB, PrrF, and FsrA) and carbon metabolism (Spot 42, CyaR, and SgrS).
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Affiliation(s)
- Gregory R Richards
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
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Nielsen JS, Larsen MH, Lillebæk EMS, Bergholz TM, Christiansen MHG, Boor KJ, Wiedmann M, Kallipolitis BH. A small RNA controls expression of the chitinase ChiA in Listeria monocytogenes. PLoS One 2011; 6:e19019. [PMID: 21533114 PMCID: PMC3078929 DOI: 10.1371/journal.pone.0019019] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Accepted: 03/14/2011] [Indexed: 02/04/2023] Open
Abstract
In recent years, more than 60 small RNAs (sRNAs) have been identified in the gram-positive human pathogen Listeria monocytogenes, but their putative roles and mechanisms of action remain largely unknown. The sRNA LhrA was recently shown to be a post-transcriptional regulator of a single gene, lmo0850, which encodes a small protein of unknown function. LhrA controls the translation and degradation of the lmo0850 mRNA by an antisense mechanism, and it depends on the RNA chaperone Hfq for efficient binding to its target. In the present study, we sought to gain more insight into the functional role of LhrA in L. monocytogenes. To this end, we determined the effects of LhrA on global-wide gene expression. We observed that nearly 300 genes in L. monocytogenes are either positively or negatively affected by LhrA. Among these genes, we identified lmo0302 and chiA as direct targets of LhrA, thus establishing LhrA as a multiple target regulator. Lmo0302 encodes a hypothetical protein with no known function, whereas chiA encodes one of two chitinases present in L. monocytogenes. We show here that LhrA acts as a post-transcriptional regulator of lmo0302 and chiA by interfering with ribosome recruitment, and we provide evidence that both LhrA and Hfq act to down-regulate the expression of lmo0302 and chiA. Furthermore, in vitro binding experiments show that Hfq stimulates the base pairing of LhrA to chiA mRNA. Finally, we demonstrate that LhrA has a negative effect on the chitinolytic activity of L. monocytogenes. In marked contrast to this, we found that Hfq has a stimulating effect on the chitinolytic activity, suggesting that Hfq plays multiple roles in the complex regulatory pathways controlling the chitinases of L. monocytogenes.
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Affiliation(s)
- Jesper S. Nielsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Marianne Halberg Larsen
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Teresa M. Bergholz
- Department of Food Science, Cornell University, Ithaca, New York, United States of America
| | - Mie H. G. Christiansen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Kathryn J. Boor
- Department of Food Science, Cornell University, Ithaca, New York, United States of America
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, New York, United States of America
| | - Birgitte H. Kallipolitis
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- * E-mail:
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Papenfort K, Vogel J. Sweet business: Spot42 RNA networks with CRP to modulate catabolite repression. Mol Cell 2011; 41:245-6. [PMID: 21292156 DOI: 10.1016/j.molcel.2011.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Spot42 is a paradigm for small RNAs that fine-tune carbon metabolism. In this issue of Molecular Cell, Beisel and Storz (2011) reveal that this conserved RNA acts through a multioutput feedforward loop to modulate the global dynamics of sugar consumption.
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Affiliation(s)
- Kai Papenfort
- Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2, D-97080 Würzburg, Germany
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McCown PJ, Roth A, Breaker RR. An expanded collection and refined consensus model of glmS ribozymes. RNA (NEW YORK, N.Y.) 2011; 17:728-36. [PMID: 21367971 PMCID: PMC3062183 DOI: 10.1261/rna.2590811] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 01/17/2011] [Indexed: 05/21/2023]
Abstract
Self-cleaving glmS ribozymes selectively bind glucosamine-6-phosphate (GlcN6P) and use this metabolite as a cofactor to promote self-cleavage by internal phosphoester transfer. Representatives of the glmS ribozyme class are found in Gram-positive bacteria where they reside in the 5' untranslated regions (UTRs) of glmS messenger RNAs that code for the essential enzyme L-glutamine:D-fructose-6-phosphate aminotransferase. By using comparative sequence analyses, we have expanded the number of glmS ribozyme representatives from 160 to 463. All but two glmS ribozymes are present in glmS mRNAs and most exhibit striking uniformity in sequence and structure, which are features that make representatives attractive targets for antibacterial drug development. However, our discovery of rare variants broadens the consensus sequence and structure model. For example, in the Deinococcus-Thermus phylum, several structural variants exist that carry additional stems within the catalytic core and changes to the architecture of core-supporting substructures. These findings reveal that glmS ribozymes have a broader phylogenetic distribution than previously known and suggest that additional rare structural variants may remain to be discovered.
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Affiliation(s)
- Phillip J McCown
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
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Abstract
Regulatory small RNAs (sRNAs), also known as non-coding RNA, are not translated into proteins and widespread in prokaryotes and eukaryotes. sRNAs involve in multiple fundamental cellular events. They are emerging regulatory elements that are gaining momentum. Knowledge of sRNA largely originates from eukaryotes. Prokaryotic sRNAs, particularly those of pathogen are only recently explored. The main types, function, and methodology to predict pathogen sRNAs are summarized in this review. Special focus is sRNAs regulating pathogen gene expression, particularly that of Mycobacterium tuberculosis, which is hitherto the most successful pathogen afflicting mankind.
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Affiliation(s)
- Yexin Zhou
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, School of Life Sciences, Southwest University, Chongqing 400715, China
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Beich-Frandsen M, Vecerek B, Konarev PV, Sjöblom B, Kloiber K, Hämmerle H, Rajkowitsch L, Miles AJ, Kontaxis G, Wallace BA, Svergun DI, Konrat R, Bläsi U, Djinovic-Carugo K. Structural insights into the dynamics and function of the C-terminus of the E. coli RNA chaperone Hfq. Nucleic Acids Res 2011; 39:4900-15. [PMID: 21330354 PMCID: PMC3113564 DOI: 10.1093/nar/gkq1346] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The hexameric Escherichia coli RNA chaperone Hfq (Hfq(Ec)) is involved in riboregulation of target mRNAs by small trans-encoded RNAs. Hfq proteins of different bacteria comprise an evolutionarily conserved core, whereas the C-terminus is variable in length. Although the structure of the conserved core has been elucidated for several Hfq proteins, no structural information has yet been obtained for the C-terminus. Using bioinformatics, nuclear magnetic resonance spectroscopy, synchrotron radiation circular dichroism (SRCD) spectroscopy and small angle X-ray scattering we provide for the first time insights into the conformation and dynamic properties of the C-terminal extension of Hfq(Ec). These studies indicate that the C-termini are flexible and extend laterally away from the hexameric core, displaying in this way features typical of intrinsically disordered proteins that facilitate intermolecular interactions. We identified a minimal, intrinsically disordered region of the C-terminus supporting the interactions with longer RNA fragments. This minimal region together with rest of the C-terminal extension provides a flexible moiety capable of tethering long and structurally diverse RNA molecules. Furthermore, SRCD spectroscopy supported the hypothesis that RNA fragments exceeding a certain length interact with the C-termini of Hfq(Ec).
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Affiliation(s)
- Mads Beich-Frandsen
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
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Resch A, Većerek B, Palavra K, Bläsi U. Requirement of the CsdA DEAD-box helicase for low temperature riboregulation of rpoS mRNA. RNA Biol 2010; 7:796-802. [PMID: 21045550 DOI: 10.4161/rna.7.6.13768] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ribosome binding site of Escherichia coli rpoS mRNA, encoding the stationary sigma-factor RpoS, is sequestered by an inhibitory stem-loop structure (iss). Translational activation of rpoS mRNA at low temperature and during exponential growth includes Hfq-facilitated duplex formation between rpoS and the small regulatory RNA DsrA as well as a concomitant re-direction of RNAse III cleavage in the 5´-untranslated region of rpoS upon DsrA·rpoS annealing. In this way, DsrA-mediated regulation does not only activate rpoS translation by disrupting the inhibitory secondary structure but also stabilizes the rpoS transcript. Although minor structural changes by Hfq have been observed in rpoS mRNA, a prevailing question concerns unfolding of the iss in rpoS at low growth temperature. Here, we have identified the DEAD-box helicase CsdA as an ancillary factor required for low temperature activation of RpoS synthesis by DsrA. The lack of RpoS synthesis observed in the csdA mutant strain at low growth temperature could be attributed to a lack of duplex formation between rpoS and DsrA, showing that at low temperature the sole action of Hfq is not sufficient to permit DsrA·rpoS annealing. An interactome study has previously indicated an association between Hfq and CsdA. However, immunological assays did not reveal a physical interaction between Hfq and CsdA. These findings add to a model, wherein Hfq binds upstream of the rpoS iss and presents DsrA in a conformation receptive to annealing. Melting of the iss by CsdA may then permit DsrA·rpoS duplex formation, and consequently rpoS translation.
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Affiliation(s)
- Armin Resch
- Department of Microbiology, University of Vienna, Vienna, Austria
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Abstract
The glmS ribozyme is the first known example of a natural ribozyme that has evolved to require binding of an exogenous small molecule for activity. In Gram-positive bacteria, this RNA domain is part of the messenger RNA (mRNA) encoding the essential enzyme that synthesizes glucosamine-6-phosphate (GlcN6P). When present at physiologic concentration, this small molecule binds to the glmS ribozyme and uncovers a latent self-cleavage activity that ultimately leads to degradation of the mRNA. Biochemical and structural studies reveal that the RNA adopts a rigid fold stabilized by three pseudoknots and the packing of a peripheral domain against the ribozyme core. GlcN6P binding to this pre-organized RNA does not induce conformational changes; rather, the small molecule functions as a coenzyme, providing a catalytically essential amine group to the active site. The ribozyme is not a passive player, however. Active site functional groups are essential for catalysis, even in the presence of GlcN6P. In addition to being a superb experimental system with which to analyze how RNA catalysts can exploit small molecule coenzymes to broaden their chemical versatility, the presence of the glmS ribozyme in numerous pathogenic bacteria make this RNA an attractive target for the development of new antibiotics and antibacterial strategies.
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Affiliation(s)
- Adrian R Ferré-D'Amaré
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA.
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Göpel Y, Lüttmann D, Heroven AK, Reichenbach B, Dersch P, Görke B. Common and divergent features in transcriptional control of the homologous small RNAs GlmY and GlmZ in Enterobacteriaceae. Nucleic Acids Res 2010; 39:1294-309. [PMID: 20965974 PMCID: PMC3045617 DOI: 10.1093/nar/gkq986] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Small RNAs GlmY and GlmZ compose a cascade that feedback-regulates synthesis of enzyme GlmS in Enterobacteriaceae. Here, we analyzed the transcriptional regulation of glmY/glmZ from Yersinia pseudotuberculosis, Salmonella typhimurium and Escherichia coli, as representatives for other enterobacterial species, which exhibit similar promoter architectures. The GlmY and GlmZ sRNAs of Y. pseudotuberculosis are transcribed from σ54-promoters that require activation by the response regulator GlrR through binding to three conserved sites located upstream of the promoters. This also applies to glmY/glmZ of S. typhimurium and glmY of E. coli, but as a difference additional σ70-promoters overlap the σ54-promoters and initiate transcription at the same site. In contrast, E. coli glmZ is transcribed from a single σ70-promoter. Thus, transcription of glmY and glmZ is controlled by σ54 and the two-component system GlrR/GlrK (QseF/QseE) in Y. pseudotuberculosis and presumably in many other Enterobacteria. However, in a subset of species such as E. coli this relationship is partially lost in favor of σ70-dependent transcription. In addition, we show that activity of the σ54-promoter of E. coli glmY requires binding of the integration host factor to sites upstream of the promoter. Finally, evidence is provided that phosphorylation of GlrR increases its activity and thereby sRNA expression.
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Affiliation(s)
- Yvonne Göpel
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, Grisebachstrasse 8, 37077 Göttingen, Germany
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The small RNA Aar in Acinetobacter baylyi: a putative regulator of amino acid metabolism. Arch Microbiol 2010; 192:691-702. [PMID: 20559624 DOI: 10.1007/s00203-010-0592-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 05/20/2010] [Accepted: 05/24/2010] [Indexed: 10/19/2022]
Abstract
Small non-coding RNAs (sRNAs) are key players in prokaryotic metabolic circuits, allowing the cell to adapt to changing environmental conditions. Regulatory interference by sRNAs in cellular metabolism is often facilitated by the Sm-like protein Hfq. A search for novel sRNAs in A. baylyi intergenic regions was performed by a biocomputational screening. One candidate, Aar, encoded between trpS and sucD showed Hfq dependency in Northern blot analysis. Aar was expressed strongly during stationary growth phase in minimal medium; in contrast, in complex medium, strongest expression was in the exponential growth phase. Whereas over-expression of Aar in trans did not affect bacterial growth, seven mRNA targets predicted by two in silico approaches were upregulated in stationary growth phase. All seven mRNAs are involved in A. baylyi amino acid metabolism. A putative binding site for Lrp, the global regulator of branched-chain amino acids in E. coli, was observed within the aar gene. Both facts imply an Aar participation in amino acid metabolism.
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