1
|
Pei X, Lei Y, Zhang H. Transcriptional regulators of secondary metabolite biosynthesis in Streptomyces. World J Microbiol Biotechnol 2024; 40:156. [PMID: 38587708 DOI: 10.1007/s11274-024-03968-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/25/2024] [Indexed: 04/09/2024]
Abstract
In the post-genome era, great progress has been made in metabolic engineering using recombinant DNA technology to enhance the production of high-value products by Streptomyces. With the development of microbial genome sequencing techniques and bioinformatic tools, a growing number of secondary metabolite (SM) biosynthetic gene clusters in Streptomyces and their biosynthetic logics have been uncovered and elucidated. In order to increase our knowledge about transcriptional regulators in SM of Streptomyces, this review firstly makes a comprehensive summary of the characterized factors involved in enhancing SM production and awakening SM biosynthesis. Future perspectives on transcriptional regulator engineering for new SM biosynthesis by Streptomyces are also provided.
Collapse
Affiliation(s)
- Xinwei Pei
- School of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Yunyun Lei
- School of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Huawei Zhang
- School of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, China.
| |
Collapse
|
2
|
Tomás-Gallardo L, Cabrera JJ, Mesa S. Surface Plasmon Resonance as a Tool to Elucidate the Molecular Determinants of Key Transcriptional Regulators Controlling Rhizobial Lifestyles. Methods Mol Biol 2024; 2751:145-163. [PMID: 38265715 DOI: 10.1007/978-1-0716-3617-6_10] [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] [Indexed: 01/25/2024]
Abstract
Bacteria must be provided with a battery of tools integrated into regulatory networks, in order to respond and, consequently, adapt their physiology to changing environments. Within these networks, transcription factors finely orchestrate the expression of genes in response to a variety of signals, by recognizing specific DNA sequences at their promoter regions. Rhizobia are host-interacting soil bacteria that face severe changes to adapt their physiology from free-living conditions to the nitrogen-fixing endosymbiotic state inside root nodules associated with leguminous plants. One of these cues is the low partial pressure of oxygen within root nodules.Surface plasmon resonance (SPR) constitutes a technique that allows to measure molecular interactions dynamics at real time by detecting changes in the refractive index of a surface. Here, we implemented the SPR methodology to analyze the discriminatory determinants of transcription factors for specific interaction with their target genes. We focused on FixK2, a CRP/FNR-type protein with a central role in the complex oxygen-responsive regulatory network in the soybean endosymbiont Bradyrhizobium diazoefficiens. Our study unveiled relevant residues for protein-DNA interaction as well as allowed us to monitor kinetics and stability protein-DNA complex. We believe that this approach can be employed for the characterization of other relevant transcription factors which can assist to the better understanding of the adaptation of bacteria with agronomic or human interest to their different modes of life.
Collapse
Affiliation(s)
- Laura Tomás-Gallardo
- Proteomics and Biochemistry Unit, Andalusian Centre for Developmental Biology, CSIC-Junta de Andalucía-Pablo de Olavide University, Seville, Spain.
| | - Juan J Cabrera
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, Granada, Spain
| | - Socorro Mesa
- Department of Soil and Plant Microbiology, Estación Experimental del Zaidín, CSIC, Granada, Spain
| |
Collapse
|
3
|
Ke N, Kumka JE, Fang M, Weaver B, Burstyn JN, Bauer CE. RedB, a Member of the CRP/FNR Family, Functions as a Transcriptional Redox Brake. Microbiol Spectr 2022; 10:e0235322. [PMID: 36106751 PMCID: PMC9603854 DOI: 10.1128/spectrum.02353-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/25/2022] [Indexed: 01/04/2023] Open
Abstract
Phylogenetic and sequence similarity network analyses of the CRP (cyclic AMP receptor protein)/FNR (fumarate and nitrate reductase regulatory protein) family of transcription factors indicate the presence of numerous subgroups, many of which have not been analyzed. Five homologs of the CRP/FNR family are present in the Rhodobacter capsulatus genome. One is a member of a broadly disseminated, previously uncharacterized CRP/FNR family subgroup encoded by the gene rcc01561. In this study, we utilize mutational disruption, transcriptome sequencing (RNA-seq), and chromatin immunoprecipitation sequencing (ChIP-seq) to determine the role of RCC01561 in regulating R. capsulatus physiology. This analysis shows that a mutant strain disrupted for rcc01561 exhibits altered expression of 451 genes anaerobically. A detailed analysis of the affected loci shows that RCC01561 represses photosynthesis and favors catabolism over anabolism and the use of the Entner-Doudoroff shunt and glycolysis over that of the tricarboxylic acid (TCA) cycle to limit NADH and ATP formation. This newly characterized CRP/FNR family member with a predominant role in reducing the production of reducing potential and ATP is given the nomenclature RedB as it functions as an energy and redox brake. Beyond limiting energy production, RedB also represses the expression of numerous genes involved in protein synthesis, including those involved in translation initiation, tRNA synthesis and charging, and amino acid biosynthesis. IMPORTANCE CRP and FNR are well-characterized members of the CRP/FNR family of regulatory proteins that function to maximize cellular energy production. In this study, we identify several new subgroups of the CRP/FNR family, many of which have not yet been characterized. Using Rhodobacter capsulatus as a model, we have mutationally disrupted the gene rcc01561, which codes for a transcription factor that is a member of a unique subgroup of the CRP/FNR family. Transcriptomic analysis shows that the disruption of rcc01561 leads to the altered expression of 451 genes anaerobically. Analysis of these regulated genes indicates that RCC01561 has a novel role in limiting cellular energy production. To our knowledge, this is first example of a member of the CRP/FNR family that functions as a brake on cellular energy production.
Collapse
Affiliation(s)
- Nijia Ke
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Joseph E. Kumka
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Mingxu Fang
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| | - Brian Weaver
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Judith N. Burstyn
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Carl E. Bauer
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA
| |
Collapse
|
4
|
Parejo S, Cabrera JJ, Jiménez-Leiva A, Tomás-Gallardo L, Bedmar EJ, Gates AJ, Mesa S. Fine-Tuning Modulation of Oxidation-Mediated Posttranslational Control of Bradyrhizobium diazoefficiens FixK 2 Transcription Factor. Int J Mol Sci 2022; 23:5117. [PMID: 35563511 PMCID: PMC9104804 DOI: 10.3390/ijms23095117] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/22/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
FixK2 is a CRP/FNR-type transcription factor that plays a central role in a sophisticated regulatory network for the anoxic, microoxic and symbiotic lifestyles of the soybean endosymbiont Bradyrhizobium diazoefficiens. Aside from the balanced expression of the fixK2 gene under microoxic conditions (induced by the two-component regulatory system FixLJ and negatively auto-repressed), FixK2 activity is posttranslationally controlled by proteolysis, and by the oxidation of a singular cysteine residue (C183) near its DNA-binding domain. To simulate the permanent oxidation of FixK2, we replaced C183 for aspartic acid. Purified C183D FixK2 protein showed both low DNA binding and in vitro transcriptional activation from the promoter of the fixNOQP operon, required for respiration under symbiosis. However, in a B. diazoefficiens strain coding for C183D FixK2, expression of a fixNOQP'-'lacZ fusion was similar to that in the wild type, when both strains were grown microoxically. The C183D FixK2 encoding strain also showed a wild-type phenotype in symbiosis with soybeans, and increased fixK2 gene expression levels and FixK2 protein abundance in cells. These two latter observations, together with the global transcriptional profile of the microoxically cultured C183D FixK2 encoding strain, suggest the existence of a finely tuned regulatory strategy to counterbalance the oxidation-mediated inactivation of FixK2 in vivo.
Collapse
Affiliation(s)
- Sergio Parejo
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Juan J. Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Laura Tomás-Gallardo
- Proteomics and Biochemistry Unit, Andalusian Centre for Developmental Biology, CSIC-Pablo de Olavide University, 41013 Seville, Spain;
| | - Eulogio J. Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| | - Andrew J. Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK;
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, 18008 Granada, Spain; (S.P.); (J.J.C.); (A.J.-L.); (E.J.B.)
| |
Collapse
|
5
|
Exploring the Meta-regulon of the CRP/FNR Family of Global Transcriptional Regulators in a Partial-Nitritation Anammox Microbiome. mSystems 2021; 6:e0090621. [PMID: 34636676 PMCID: PMC8510549 DOI: 10.1128/msystems.00906-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microorganisms must respond to environmental changes to survive, often by controlling transcription initiation. Intermittent aeration during wastewater treatment presents a cyclically changing environment to which microorganisms must react. We used an intermittently aerated bioreactor performing partial nitritation and anammox (PNA) to investigate how the microbiome responds to recurring change. Meta-transcriptomic analysis revealed a dramatic disconnect between the relative DNA abundance and gene expression within the metagenome-assembled genomes (MAGs) of community members, suggesting the importance of transcriptional regulation in this microbiome. To explore how community members responded to cyclic aeration via transcriptional regulation, we searched for homologs of the catabolite repressor protein/fumarate and nitrate reductase regulatory protein (CRP/FNR) family of transcription factors (TFs) within the MAGs. Using phylogenetic analyses, evaluation of sequence conservation in important amino acid residues, and prediction of genes regulated by TFs in the MAGs, we identified homologs of the oxygen-sensing FNR in Nitrosomonas and Rhodocyclaceae, nitrogen-sensing dissimilative nitrate respiration regulator that responds to nitrogen species (DNR) in Rhodocyclaceae, and nitrogen-sensing nitrite and nitric oxide reductase regulator that responds to nitrogen species (NnrR) in Nitrospira MAGs. Our data also predict that CRP/FNR homologs in Ignavibacteria, Flavobacteriales, and Saprospiraceae MAGs sense carbon availability. In addition, a CRP/FNR homolog in a Brocadia MAG was most closely related to CRP TFs known to sense carbon sources in well-studied organisms. However, we predict that in autotrophic Brocadia, this TF most likely regulates a diverse set of functions, including a response to stress during the cyclic aerobic/anoxic conditions. Overall, this analysis allowed us to define a meta-regulon of the PNA microbiome that explains functions and interactions of the most active community members. IMPORTANCE Microbiomes are important contributors to many ecosystems, including ones where nutrient cycling is stimulated by aeration control. Optimizing cyclic aeration helps reduce energy needs and maximize microbiome performance during wastewater treatment; however, little is known about how most microbial community members respond to these alternating conditions. We defined the meta-regulon of a PNA microbiome by combining existing knowledge of how the CRP/FNR family of bacterial TFs respond to stimuli, with metatranscriptomic analyses to characterize gene expression changes during aeration cycles. Our results indicated that, for some members of the community, prior knowledge is sufficient for high-confidence assignments of TF function, whereas other community members have CRP/FNR TFs for which inferences of function are limited by lack of prior knowledge. This study provides a framework to begin elucidating meta-regulons in microbiomes, where pure cultures are not available for traditional transcriptional regulation studies. Defining the meta-regulon can help in optimizing microbiome performance.
Collapse
|
6
|
Sousa EH, Carepo MS, Moura JJ. Nitrate-nitrite fate and oxygen sensing in dormant Mycobacterium tuberculosis: A bioinorganic approach highlighting the importance of transition metals. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
|
7
|
Singh R, Ranaivoarisoa TO, Gupta D, Bai W, Bose A. Genetic Redundancy in Iron and Manganese Transport in the Metabolically Versatile Bacterium Rhodopseudomonas palustris TIE-1. Appl Environ Microbiol 2020; 86:e01057-20. [PMID: 32503905 PMCID: PMC7414945 DOI: 10.1128/aem.01057-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 05/31/2020] [Indexed: 12/24/2022] Open
Abstract
The purple nonsulfur bacterium Rhodopseudomonas palustris TIE-1 can produce useful biochemicals such as bioplastics and biobutanol. Production of such biochemicals requires intracellular electron availability, which is governed by the availability and the transport of essential metals such as iron (Fe). Because of the distinct chemical properties of ferrous [Fe(II)] and ferric iron [Fe(III)], different systems are required for their transport and storage in bacteria. Although Fe(III) transport systems are well characterized, we know much less about Fe(II) transport systems except for the FeoAB system. Iron transporters can also import manganese (Mn). We studied Fe and Mn transport by five putative Fe transporters in TIE-1 under metal-replete, metal-depleted, oxic, and anoxic conditions. We observed that by overexpressing feoAB, efeU, and nramp1AB, the intracellular concentrations of Fe and Mn can be enhanced in TIE-1 under oxic and anoxic conditions, respectively. The deletion of a single gene/operon does not attenuate Fe or Mn uptake in TIE-1 regardless of the growth conditions used. This indicates that genetically dissimilar yet functionally redundant Fe transporters in TIE-1 can complement each other. Relative gene expression analysis shows that feoAB and efeU are expressed during Fe and Mn depletion under both oxic and anoxic conditions. The promoters of these transporter genes contain a combination of Fur and Fnr boxes, suggesting that their expression is regulated by both Fe and oxygen availability. The findings from this study will help us modulate intracellular Fe and Mn concentrations, ultimately improving TIE-1's ability to produce desirable biomolecules.IMPORTANCERhodopseudomonas palustris TIE-1 is a metabolically versatile bacterium that can use various electron donors, including Fe(II) and poised electrodes, for photoautotrophic growth. TIE-1 can produce useful biomolecules, such as biofuels and bioplastics, under various growth conditions. Production of such reduced biomolecules is controlled by intracellular electron availability, which, in turn, is mediated by various iron-containing proteins in the cell. Several putative Fe transporters exist in TIE-1's genome. Some of these transporters can also transport Mn, part of several important cellular enzymes. Therefore, understanding the ability to transport and respond to various levels of Fe and Mn under different conditions is important to improve TIE-1's ability to produce useful biomolecules. Our data suggest that by overexpressing Fe transporter genes via plasmid-based expression, we can increase the import of Fe and Mn in TIE-1. Future work will leverage these data to improve TIE-1 as an attractive microbial chassis and future biotechnological workhorse.
Collapse
Affiliation(s)
- Rajesh Singh
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Dinesh Gupta
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Wei Bai
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| |
Collapse
|
8
|
Rova M, Hellberg Lindqvist M, Goetelen T, Blomqvist S, Nilsson T. Heterologous expression of the gene for chlorite dismutase from Ideonella dechloratans is induced by an FNR-type transcription factor. Microbiologyopen 2020; 9:e1049. [PMID: 32319739 PMCID: PMC7349173 DOI: 10.1002/mbo3.1049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 01/30/2023] Open
Abstract
Regulation of the expression of the gene for chlorite dismutase (cld), located on the chlorate reduction composite transposon of the chlorate reducer Ideonella dechloratans, was studied. A 200 bp upstream sequence of the cld gene, and mutated and truncated versions thereof, was used in a reporter system in Escherichia coli. It was found that a sequence within this upstream region, which is nearly identical to the canonical FNR-binding sequence of E. coli, is necessary for anaerobic induction of the reporter gene. Anaerobic induction was regained in an FNR-deficient strain of E. coli when supplemented either with the fnr gene from E. coli or with a candidate fnr gene cloned from I. dechloratans. In vivo transcription of the suggested fnr gene of I. dechloratans was demonstrated by qRT-PCR. Based on these results, the cld promoter of I. dechloratans is suggested to be a class II-activated promoter regulated by an FNR-type protein of I. dechloratans. No fnr-type genes have been found on the chlorate reduction composite transposon of I. dechloratans, making anaerobic upregulation of the cld gene after a gene transfer event dependent on the presence of an fnr-type gene in the recipient.
Collapse
Affiliation(s)
- Maria Rova
- Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden
| | | | - Thijs Goetelen
- Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden
| | - Shady Blomqvist
- Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden
| | - Thomas Nilsson
- Department of Engineering and Chemical Sciences, Karlstad University, Karlstad, Sweden
| |
Collapse
|
9
|
Willemin MS, Vingerhoets M, Holliger C, Maillard J. Hybrid Transcriptional Regulators for the Screening of Target DNA Motifs in Organohalide-Respiring Bacteria. Front Microbiol 2020; 11:310. [PMID: 32194528 PMCID: PMC7062800 DOI: 10.3389/fmicb.2020.00310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
The bioremediation of persistent organohalide molecules under anoxic conditions mostly relies on the bacterial process called organohalide respiration (OHR). Organohalide-respiring bacteria (OHRB) are phylogenetically diverse anaerobic bacteria that share the capacity to use organohalides as terminal electron acceptors in an energy-conserving process. The reductive dehalogenase (rdh) gene clusters encode for proteins specialized in the respiration of one or a limited number of organohalides. One particular OHRB may harbor up to several dozens of rdh gene clusters suggesting a wide potential for bioremediation. To avoid wasting energy in producing unnecessary proteins, rdh gene clusters often include a transcriptional regulator. In organohalide-respiring Firmicutes, RdhK is a dedicated transcriptional regulator of OHR and represents a subfamily of proteins among the CRP/FNR superfamily of regulators. RdhK proteins are composed of an effector-binding domain (EBD) which recognizes a given organohalide and subsequently controls the interaction of its C-terminal DNA-binding domain (DBD) with a DNA motif (referred to as dehalobox, or DB) located in the promoter region of the target rdh genes. The two binding partners (i.e. an organohalide molecule and a DB sequence) of RdhK proteins are interdependent which impairs the exploration of OHR regulatory networks. Here, we propose a strategy relying on hybrid proteins to efficiently screen the DNA target of a single RdhK protein without prior knowledge on its effector. To demonstrate the potential of the method, two hybrids with alternative fusion points were designed based on RdhK6 EBD and RdhK1 DBD from Desulfitobacterium hafniense. Electrophoretic mobility shift assay was performed with purified hybrids along with the parental proteins and their binding properties were further tested in vivo through a β-galactosidase reporter assay. Along with revealing new RdhK6 features, we show that both hybrids resulted in active regulatory proteins with distinct binding patterns. While Hybrid A was less specific for the DNA motif, Hybrid B successfully mimicked the binding behavior of the parental proteins and thus represents a promising template for the design of new RdhK hybrids to screen yet uncharacterized RdhK proteins and also possibly other members of the CRP/FNR superfamily.
Collapse
Affiliation(s)
- Mathilde Stéphanie Willemin
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Marie Vingerhoets
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christof Holliger
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Maillard
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| |
Collapse
|
10
|
Batista MB, Chandra G, Monteiro RA, de Souza EM, Dixon R. Hierarchical interactions between Fnr orthologs allows fine-tuning of transcription in response to oxygen in Herbaspirillum seropedicae. Nucleic Acids Res 2019. [PMID: 29529262 PMCID: PMC5934665 DOI: 10.1093/nar/gky142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bacteria adjust the composition of their electron transport chain (ETC) to efficiently adapt to oxygen gradients. This involves differential expression of various ETC components to optimize energy generation. In Herbaspirillum seropedicae, reprogramming of gene expression in response to oxygen availability is controlled at the transcriptional level by three Fnr orthologs. Here, we characterised Fnr regulons using a combination of RNA-Seq and ChIP-Seq analysis. We found that Fnr1 and Fnr3 directly regulate discrete groups of promoters (Groups I and II, respectively), and that a third group (Group III) is co-regulated by both transcription factors. Comparison of DNA binding motifs between the three promoter groups suggests Group III promoters are potentially co-activated by Fnr3–Fnr1 heterodimers. Specific interaction between Fnr1 and Fnr3, detected in two-hybrid assays, was dependent on conserved residues in their dimerization interfaces, indicative of heterodimer formation in vivo. The requirements for co-activation of the fnr1 promoter, belonging to Group III, suggest either sequential activation by Fnr3 and Fnr1 homodimers or the involvement of Fnr3–Fnr1 heterodimers. Analysis of Fnr proteins with swapped activation domains provides evidence that co-activation by Fnr1 and Fnr3 at Group III promoters optimises interactions with RNA polymerase to fine-tune transcription in response to prevailing oxygen concentrations.
Collapse
Affiliation(s)
- Marcelo Bueno Batista
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Rose Adele Monteiro
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, P.O. Box 19046, Curitiba, PR 81531-990, Brazil
| | - Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, P.O. Box 19046, Curitiba, PR 81531-990, Brazil
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| |
Collapse
|
11
|
Ranganathan S, Cheung J, Cassidy M, Ginter C, Pata JD, McDonough KA. Novel structural features drive DNA binding properties of Cmr, a CRP family protein in TB complex mycobacteria. Nucleic Acids Res 2019; 46:403-420. [PMID: 29165665 PMCID: PMC5758884 DOI: 10.1093/nar/gkx1148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) encodes two CRP/FNR family transcription factors (TF) that contribute to virulence, Cmr (Rv1675c) and CRPMt (Rv3676). Prior studies identified distinct chromosomal binding profiles for each TF despite their recognizing overlapping DNA motifs. The present study shows that Cmr binding specificity is determined by discriminator nucleotides at motif positions 4 and 13. X-ray crystallography and targeted mutational analyses identified an arginine-rich loop that expands Cmr’s DNA interactions beyond the classical helix-turn-helix contacts common to all CRP/FNR family members and facilitates binding to imperfect DNA sequences. Cmr binding to DNA results in a pronounced asymmetric bending of the DNA and its high level of cooperativity is consistent with DNA-facilitated dimerization. A unique N-terminal extension inserts between the DNA binding and dimerization domains, partially occluding the site where the canonical cAMP binding pocket is found. However, an unstructured region of this N-terminus may help modulate Cmr activity in response to cellular signals. Cmr’s multiple levels of DNA interaction likely enhance its ability to integrate diverse gene regulatory signals, while its novel structural features establish Cmr as an atypical CRP/FNR family member.
Collapse
Affiliation(s)
- Sridevi Ranganathan
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, NY 12201, USA
| | - Jonah Cheung
- New York Structural Biology Center, New York, NY 10027, USA
| | | | | | - Janice D Pata
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, NY 12201, USA.,Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| | - Kathleen A McDonough
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany, NY 12201, USA.,Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| |
Collapse
|
12
|
Orb-weaving spider Araneus ventricosus genome elucidates the spidroin gene catalogue. Sci Rep 2019; 9:8380. [PMID: 31182776 PMCID: PMC6557832 DOI: 10.1038/s41598-019-44775-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/22/2019] [Indexed: 02/02/2023] Open
Abstract
Members of the family Araneidae are common orb-weaving spiders, and they produce several types of silks throughout their behaviors and lives, from reproduction to foraging. Egg sac, prey capture thread, or dragline silk possesses characteristic mechanical properties, and its variability makes it a highly attractive material for ecological, evolutional, and industrial fields. However, the complete set of constituents of silks produced by a single species is still unclear, and novel spidroin genes as well as other proteins are still being found. Here, we present the first genome in genus Araneus together with the full set of spidroin genes with unamplified long reads and confirmed with transcriptome of the silk glands and proteome analysis of the dragline silk. The catalogue includes the first full length sequence of a paralog of major ampullate spidroin MaSp3, and several spider silk-constituting elements designated SpiCE. Family-wide phylogenomic analysis of Araneidae suggests the relatively recent acquisition of these genes, and multiple-omics analyses demonstrate that these proteins are critical components in the abdominal spidroin gland and dragline silk, contributing to the outstanding mechanical properties of silk in this group of species.
Collapse
|
13
|
Abstract
Organohalide respiration (OHR) is an anaerobic metabolism by which bacteria conserve energy with the use of halogenated compounds as terminal electron acceptors. Genes involved in OHR are organized in reductive dehalogenase (rdh) gene clusters and can be found in relatively high copy numbers in the genomes of organohalide-respiring bacteria (OHRB). The minimal rdh gene set is composed by rdhA and rdhB, encoding the catalytic enzyme involved in reductive dehalogenation and its putative membrane anchor, respectively. In this chapter, we present the major findings concerning the regulatory strategies developed by OHRB to control the expression of the rdh gene clusters. The first section focuses on the description of regulation patterns obtained from targeted transcriptional analyses, and from transcriptomic and proteomic studies, while the second section offers a detailed overview of the biochemically characterized OHR regulatory proteins identified so far. Depending on OHRB, transcriptional regulators belonging to three different protein families are found in the direct vicinity of rdh gene clusters, suggesting that they activate the transcription of their cognate gene cluster. In this chapter, strong emphasis was laid on the family of CRP/FNR-type RdhK regulators which belong to members of the genera Dehalobacter and Desulfitobacterium. Whereas only chlorophenols have been identified as effectors for RdhK regulators, the protein sequence diversity suggests a broader organohalide spectrum. Thus, effector identification of new regulators offers a promising alternative to elucidate the substrates of yet uncharacterized reductive dehalogenases. Future work investigating the possible cross-talk between OHR regulators and their possible use as biosensors is discussed.
Collapse
|
14
|
Mettert EL, Kiley PJ. Reassessing the Structure and Function Relationship of the O 2 Sensing Transcription Factor FNR. Antioxid Redox Signal 2018; 29:1830-1840. [PMID: 28990402 PMCID: PMC6217745 DOI: 10.1089/ars.2017.7365] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE The Escherichia coli regulatory protein fumarate nitrate reduction (FNR) mediates a global transcriptional response upon O2 deprivation. Spanning nearly 40 years of research investigations, our understanding of how FNR senses and responds to O2 has considerably progressed despite a lack of structural information for most of that period. This knowledge has established the paradigm for how facultative anaerobic bacteria sense changes in O2 tension. Recent Advances: Recently, the X-ray crystal structure of Aliivibrio fischeri FNR with its [4Fe-4S] cluster cofactor was solved and has provided valuable new insight into FNR structure and function. These findings have alluded to the conformational changes that may occur to alter FNR activity in response to O2. CRITICAL ISSUES Here, we review the major features of this structure in context of previously acquired data. In doing so, we discuss additional mechanistic aspects of FNR function that warrant further investigation. FUTURE DIRECTIONS To complement the [4Fe-4S]-FNR structure, the structures of apo-FNR and FNR bound to DNA or RNA polymerase are needed. Together, these structures would elevate our understanding of how ligation of its [4Fe-4S] cluster allows FNR to regulate transcription according to the level of environmental O2.
Collapse
Affiliation(s)
- Erin L Mettert
- Department of Biomolecular Chemistry, University of Wisconsin-Madison , Madison, Wisconsin
| | - Patricia J Kiley
- Department of Biomolecular Chemistry, University of Wisconsin-Madison , Madison, Wisconsin
| |
Collapse
|
15
|
Nagata S, Imai J, Makino G, Tomita M, Kanai A. Evolutionary Analysis of HIV-1 Pol Proteins Reveals Representative Residues for Viral Subtype Differentiation. Front Microbiol 2017; 8:2151. [PMID: 29163435 PMCID: PMC5666293 DOI: 10.3389/fmicb.2017.02151] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/20/2017] [Indexed: 11/15/2022] Open
Abstract
RNA viruses have been used as model systems to understand the patterns and processes of molecular evolution because they have high mutation rates and are genetically diverse. Human immunodeficiency virus 1 (HIV-1), the etiological agent of acquired immune deficiency syndrome, is highly genetically diverse, and is classified into several groups and subtypes. However, it has been difficult to use its diverse sequences to establish the overall phylogenetic relationships of different strains or the trends in sequence conservation with the construction of phylogenetic trees. Our aims were to systematically characterize HIV-1 subtype evolution and to identify the regions responsible for HIV-1 subtype differentiation at the amino acid level in the Pol protein, which is often used to classify the HIV-1 subtypes. In this study, we systematically characterized the mutation sites in 2,052 Pol proteins from HIV-1 group M (144 subtype A; 1,528 subtype B; 380 subtype C), using sequence similarity networks. We also used spectral clustering to group the sequences based on the network graph structures. A stepwise analysis of the cluster hierarchies allowed us to estimate a possible evolutionary pathway for the Pol proteins. The subtype A sequences also clustered according to when and where the viruses were isolated, whereas both the subtype B and C sequences remained as single clusters. Because the Pol protein has several functional domains, we identified the regions that are discriminative by comparing the structures of the domain-based networks. Our results suggest that sequence changes in the RNase H domain and the reverse transcriptase (RT) connection domain are responsible for the subtype classification. By analyzing the different amino acid compositions at each site in both domain sequences, we found that a few specific amino acid residues (i.e., M357 in the RT connection domain and Q480, Y483, and L491 in the RNase H domain) represent the differences among the subtypes. These residues were located on the surface of the RT structure and in the vicinity of the amino acid sites responsible for RT enzymatic activity or function.
Collapse
Affiliation(s)
- Shohei Nagata
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.,Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan
| | - Junnosuke Imai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Gakuto Makino
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.,Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan.,Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| |
Collapse
|
16
|
Rozo ZLC, Márquez-Ortiz RA, Castro BE, Gómez NV, Escobar-Pérez J. Participation of the arcRACME protein in self-activation of the arc operon located in the arginine catabolism mobile element in pandemic clone USA300. Mem Inst Oswaldo Cruz 2017; 112:499-503. [PMID: 28591311 PMCID: PMC5452487 DOI: 10.1590/0074-02760160424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 03/04/2017] [Indexed: 11/21/2022] Open
Abstract
Staphylococcus aureus pandemic clone USA300 has, in addition to its constitutive arginine catabolism (arc) gene cluster, an arginine catabolism mobile element (ACME) carrying another such cluster, which gives this clone advantages in colonisation and infection. Gene arcR, which encodes an oxygen-sensitive transcriptional regulator, is inside ACME and downstream of the constitutive arc gene cluster, and this situation may have an impact on its activation. Different relative expression behaviours are proven here for arcRACME and the arcACME operon compared to the constitutive ones. We also show that the artificially expressed recombinant ArcRACME protein binds to the promoter region of the arcACME operon; this mechanism can be related to a positive feedback model, which may be responsible for increased anaerobic survival of the USA300 clone during infection-related processes.
Collapse
|
17
|
Structural basis for glutathione-mediated activation of the virulence regulatory protein PrfA in Listeria. Proc Natl Acad Sci U S A 2016; 113:14733-14738. [PMID: 27930316 DOI: 10.1073/pnas.1614028114] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Infection by the human bacterial pathogen Listeria monocytogenes is mainly controlled by the positive regulatory factor A (PrfA), a member of the Crp/Fnr family of transcriptional activators. Published data suggest that PrfA requires the binding of a cofactor for full activity, and it was recently proposed that glutathione (GSH) could fulfill this function. Here we report the crystal structures of PrfA in complex with GSH and in complex with GSH and its cognate DNA, the hly operator PrfA box motif. These structures reveal the structural basis for a GSH-mediated allosteric mode of activation of PrfA in the cytosol of the host cell. The crystal structure of PrfAWT in complex only with DNA confirms that PrfAWT can adopt a DNA binding-compatible structure without binding the GSH activator molecule. By binding to PrfA in the cytosol of the host cell, GSH induces the correct fold of the HTH motifs, thus priming the PrfA protein for DNA interaction.
Collapse
|
18
|
Huang Y, Yang D, Pan G, Tang GL, Shen B. Characterization of LnmO as a pathway-specific Crp/Fnr-type positive regulator for leinamycin biosynthesis in Streptomyces atroolivaceus and its application for titer improvement. Appl Microbiol Biotechnol 2016; 100:10555-10562. [PMID: 27704182 DOI: 10.1007/s00253-016-7864-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 08/31/2016] [Accepted: 09/13/2016] [Indexed: 10/20/2022]
Abstract
The cyclic adenosine monophosphate (cAMP) receptor protein/fumarate and nitrate reductase regulatory protein (Crp/Fnr) family of transcriptional regulators are pleiotropic transcriptional regulators that control a broad range of cellular functions. Leinamycin (LNM) is a potent antitumor antibiotic produced by Streptomyces atroolivaceus S-140. We previously cloned and characterized the lnm biosynthetic gene cluster from S. atroolivaceus S-140. We here report inactivation of lnmO in S. atroolivaceus S-140 and overexpression of lnmO in the S. atroolivaceus S-140 wild-type and ∆lnmE mutant SB3033 to investigate its role in LNM biosynthesis. Bioinformatics analysis revealed LnmO as the only regulator within the lnm gene cluster, exhibiting high sequence similarity to known Crp/Fnr family regulators. The inactivation of lnmO in S. atroolivaceus S-140 completely abolished LNM production but caused no apparent morphological changes, supporting that LnmO is indispensable and specific to LNM biosynthesis. Overexpression of lnmO in S. atroolivaceus S-140 and SB3033 resulted in three- and fourfold increase in LNM and LNM E1 production, respectively, supporting that LnmO acts as a positive regulator. While all of the Crp/Fnr family regulators studied to date appeared to be pleiotropic, our results support LnmO as the first Crp/Fnr family regulator that is pathway-specific. LnmO joins the growing list of regulators that could be exploited to improve secondary metabolite production in Streptomyces. Engineered strains overproducing LNM and LNM E1 will facilitate further mechanistic studies and clinical evaluation of LNM and LNM E1 as novel anticancer drugs.
Collapse
Affiliation(s)
- Yong Huang
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA.,Xiangya International Academy of Translational Medicine, Central South University, Changsha, Hunan, 410013, China
| | - Dong Yang
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Guohui Pan
- Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Gong-Li Tang
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA.,State Key Laboratory of Bioorganic and Natural Product Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Rd, Shanghai, 200032, China
| | - Ben Shen
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA. .,Department of Chemistry, The Scripps Research Institute, Jupiter, FL, 33458, USA. .,Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL, 33458, USA. .,Natural Products Library Initiative at The Scripps Research institute, The Scripps Research Institute, Jupiter, FL, 33458, USA.
| |
Collapse
|
19
|
Kılıç S, Erill I. Assessment of transfer methods for comparative genomics of regulatory networks in bacteria. BMC Bioinformatics 2016; 17 Suppl 8:277. [PMID: 27586594 PMCID: PMC5009822 DOI: 10.1186/s12859-016-1113-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Comparative genomics can leverage the vast amount of available genomic sequences to reconstruct and analyze transcriptional regulatory networks in Bacteria, but the efficacy of this approach hinges on the ability to transfer regulatory network information from reference species to the genomes under analysis. Several methods have been proposed to transfer regulatory information between bacterial species, but the paucity and distributed nature of experimental information on bacterial transcriptional networks have prevented their systematic evaluation. Results We report the compilation of a large catalog of transcription factor-binding sites across Bacteria and its use to systematically benchmark proposed transfer methods across pairs of bacterial species. We evaluate motif- and accuracy-based metrics to assess the results of regulatory network transfer and we identify the precision-recall area-under-the-curve as the best metric for this purpose due to the large class-imbalanced nature of the problem. Methods assuming conservation of the transcription factor-binding motif (motif-based) are shown to substantially outperform those assuming conservation of regulon composition (network-based), even though their efficiency can decrease sharply with increasing phylogenetic distance. Variations of the basic motif-based transfer method do not yield significant improvements in transfer accuracy. Our results indicate that detection of a large enough number of regulated orthologs is critical for network-based transfer methods, but that relaxing orthology requirements does not improve results. Using the transcriptional regulators LexA and Fur as case examples, we also show how DNA-binding domain sequence similarity can yield confounding results as an indicator of transfer efficiency for motif-based methods. Conclusions Counter to standard practice, our evaluation of metrics to assess the efficiency of methods for regulatory network information transfer reveals that the area under precision-recall (PR) curves is a more precise and informative metric than that of receiver-operating-characteristic (ROC) curves, confirming similar findings in other class-imbalanced settings. Our systematic assessment of transfer methods reveals that simple approaches to both motif- and network-based transfer of regulatory information provide equal or better results than more elaborate methods. We also show that there are not effective predictors of transfer efficacy, substantiating the long-standing practice of manual curation in comparative genomics analyses. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1113-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sefa Kılıç
- Department of Biological Sciences, University of Maryland Baltimore County (UMBC), Baltimore, MD, 21250, USA
| | - Ivan Erill
- Department of Biological Sciences, University of Maryland Baltimore County (UMBC), Baltimore, MD, 21250, USA.
| |
Collapse
|
20
|
Tsoy OV, Ravcheev DA, Čuklina J, Gelfand MS. Nitrogen Fixation and Molecular Oxygen: Comparative Genomic Reconstruction of Transcription Regulation in Alphaproteobacteria. Front Microbiol 2016; 7:1343. [PMID: 27617010 PMCID: PMC4999443 DOI: 10.3389/fmicb.2016.01343] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/15/2016] [Indexed: 11/13/2022] Open
Abstract
Biological nitrogen fixation plays a crucial role in the nitrogen cycle. An ability to fix atmospheric nitrogen, reducing it to ammonium, was described for multiple species of Bacteria and Archaea. The transcriptional regulatory network for nitrogen fixation was extensively studied in several representatives of the class Alphaproteobacteria. This regulatory network includes the activator of nitrogen fixation NifA, working in tandem with the alternative sigma-factor RpoN as well as oxygen-responsive regulatory systems, one-component regulators FnrN/FixK and two-component system FixLJ. Here we used a comparative genomics approach for in silico study of the transcriptional regulatory network in 50 genomes of Alphaproteobacteria. We extended the known regulons and proposed the scenario for the evolution of the nitrogen fixation transcriptional network. The reconstructed network substantially expands the existing knowledge of transcriptional regulation in nitrogen-fixing microorganisms and can be used for genetic experiments, metabolic reconstruction, and evolutionary analysis.
Collapse
Affiliation(s)
- Olga V Tsoy
- Research and Training Center on Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Dmitry A Ravcheev
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg Esch-sur-Alzette, Luxembourg
| | - Jelena Čuklina
- Research and Training Center on Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia; Moscow Institute of Physics and TechnologyDolgoprudny, Russia
| | - Mikhail S Gelfand
- Research and Training Center on Bioinformatics, A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia; Faculty of Bioengineering and Bioinformatics, Moscow State UniversityMoscow, Russia; Skolkovo Institute of Science and TechnologySkolkovo, Russia; Faculty of Computer Science, Higher School of EconomicsMoscow, Russia
| |
Collapse
|
21
|
Lee HJ, Gottesman S. sRNA roles in regulating transcriptional regulators: Lrp and SoxS regulation by sRNAs. Nucleic Acids Res 2016; 44:6907-23. [PMID: 27137887 PMCID: PMC5001588 DOI: 10.1093/nar/gkw358] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/21/2016] [Indexed: 11/13/2022] Open
Abstract
Post-transcriptional regulation of transcription factors contributes to regulatory circuits. We created translational reporter fusions for multiple central regulators in Escherichia coli and examined the effect of Hfq-dependent non-coding RNAs on these fusions. This approach yields an 'RNA landscape,' identifying Hfq-dependent sRNAs that regulate a given fusion. No significant sRNA regulation of crp or fnr was detected. hns was regulated only by DsrA, as previously reported. Lrp and SoxS were both found to be regulated post-transcriptionally. Lrp, ' L: eucine-responsive R: egulatory P: rotein,' regulates genes involved in amino acid biosynthesis and catabolism and other cellular functions. sRNAs DsrA, MicF and GcvB each independently downregulate the lrp translational fusion, confirming previous reports for MicF and GcvB. MicF and DsrA interact with an overlapping site early in the lrp ORF, while GcvB acts upstream at two independent sites in the long lrp leader. Surprisingly, GcvB was found to be responsible for significant downregulation of lrp after oxidative stress; MicF also contributed. SoxS, an activator of genes used to combat oxidative stress, is negatively regulated by sRNA MgrR. This study demonstrates that while not all global regulators are subject to sRNA regulation, post-transcriptional control by sRNAs allows multiple environmental signals to affect synthesis of the transcriptional regulator.
Collapse
Affiliation(s)
- Hyun-Jung Lee
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Susan Gottesman
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
22
|
Crack JC, Hutchings MI, Thomson AJ, Le Brun NE. Biochemical properties of Paracoccus denitrificans FnrP: reactions with molecular oxygen and nitric oxide. J Biol Inorg Chem 2016; 21:71-82. [PMID: 26790880 PMCID: PMC4771820 DOI: 10.1007/s00775-015-1326-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/23/2015] [Indexed: 02/04/2023]
Abstract
In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe–4S] cluster-containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe–4S] to [2Fe–2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~sixfold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer–dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe–4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers.
Collapse
Affiliation(s)
- Jason C Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Matthew I Hutchings
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew J Thomson
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| |
Collapse
|
23
|
Network-Thinking: Graphs to Analyze Microbial Complexity and Evolution. Trends Microbiol 2016; 24:224-237. [PMID: 26774999 PMCID: PMC4766943 DOI: 10.1016/j.tim.2015.12.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/02/2015] [Accepted: 12/08/2015] [Indexed: 01/23/2023]
Abstract
The tree model and tree-based methods have played a major, fruitful role in evolutionary studies. However, with the increasing realization of the quantitative and qualitative importance of reticulate evolutionary processes, affecting all levels of biological organization, complementary network-based models and methods are now flourishing, inviting evolutionary biology to experience a network-thinking era. We show how relatively recent comers in this field of study, that is, sequence-similarity networks, genome networks, and gene families–genomes bipartite graphs, already allow for a significantly enhanced usage of molecular datasets in comparative studies. Analyses of these networks provide tools for tackling a multitude of complex phenomena, including the evolution of gene transfer, composite genes and genomes, evolutionary transitions, and holobionts. Introgressive processes shape the microbial world at all levels of organisation. This reticulated evolution is increasingly studied by sequence-similarity networks. They provide an inclusive accurate multilevel framework to study the web of life. Networks enhance analyses of microbial genes, genomes, communities, and of symbiosis.
Collapse
|
24
|
Augimeri RV, Strap JL. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582. Front Microbiol 2015; 6:1459. [PMID: 26733991 PMCID: PMC4686702 DOI: 10.3389/fmicb.2015.01459] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/04/2015] [Indexed: 01/22/2023] Open
Abstract
Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature.
Collapse
Affiliation(s)
| | - Janice L. Strap
- Molecular Microbial Biochemistry Laboratory, Faculty of Science, University of Ontario Institute of Technology, OshawaON, Canada
| |
Collapse
|
25
|
Hamashima K, Tomita M, Kanai A. Expansion of Noncanonical V-Arm-Containing tRNAs in Eukaryotes. Mol Biol Evol 2015; 33:530-40. [DOI: 10.1093/molbev/msv253] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
|
26
|
Hu J, Wang F, Han SB, Wu SL, Wu M, Xu XW. Genome sequence of facultatively anaerobic marine bacterium Maribacter thermophilus strain HT7-2(T). Mar Genomics 2015; 24 Pt 3:265-8. [PMID: 26342991 DOI: 10.1016/j.margen.2015.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 08/08/2015] [Accepted: 08/12/2015] [Indexed: 10/23/2022]
Abstract
Maribacter thermophilus strain HT7-2(T), isolated from Ulva prolifera collected from the intertidal zone of Qingdao sea area, China. To date, M. thermophilus strain HT7-2(T) is the only one which has been found that has a relatively higher optimum temperature compared to other Maribacter species and it is also the first strain to be described that is facultatively anaerobic while other identified strains within genus Maribacter are strictly aerobic. Meanwhile, M. thermophilus strain HT7-2(T) harbors several coding genes related to heavy metal resistance and to antibiotics, which increase the robustness of the strain. Here, we report the genome sequence and annotation of M. thermophilus strain HT7-2(T), which comprises 4,050,606 bp with G+C content of 38.93%. A total of 3585 protein coding genes, 41 tRNAs and 6rRNAs were obtained. The genome annotation may provide basic information on some special traits and pathways in this strain.
Collapse
Affiliation(s)
- Jing Hu
- College of Life Sciences, Zhejiang University, Hangzhou, PR China
| | - Fang Wang
- College of Life Sciences, Zhejiang University, Hangzhou, PR China
| | - Shuai-Bo Han
- College of Life Sciences, Zhejiang University, Hangzhou, PR China
| | - Sang-Ling Wu
- Analysis Center of Agrobiology and Environmental Sciences, Faculty of Agriculture, Life and Environment Sciences, Zhejiang University, PR China
| | - Min Wu
- College of Life Sciences, Zhejiang University, Hangzhou, PR China.
| | - Xue-Wei Xu
- Laboratory of Marine Ecosystem and Biogeochemistry, State Oceanic Administration, Hangzhou, PR China.
| |
Collapse
|
27
|
Batista MB, Wassem R, Pedrosa FDO, de Souza EM, Dixon R, Monteiro RA. Enhanced oxygen consumption in Herbaspirillum seropedicae fnr mutants leads to increased NifA mediated transcriptional activation. BMC Microbiol 2015; 15:95. [PMID: 25947294 PMCID: PMC4422417 DOI: 10.1186/s12866-015-0432-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/24/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Orthologous proteins of the Crp/Fnr family have been previously implicated in controlling expression and/or activity of the NifA transcriptional activator in some diazotrophs. This study aimed to address the role of three Fnr-like proteins from H. seropedicae SmR1 in controlling NifA activity and consequent NifA-mediated transcription activation. RESULTS The activity of NifA-dependent transcriptional fusions (nifA::lacZ and nifB::lacZ) was analysed in a series of H. seropedicae fnr deletion mutant backgrounds. We found that combined deletions in both the fnr1 and fnr3 genes lead to higher expression of both the nifA and nifB genes and also an increased level of nifH transcripts. Expression profiles of nifB under different oxygen concentrations, together with oxygen consumption measurements suggest that the triple fnr mutant has higher respiratory activity when compared to the wild type, which we believe to be responsible for greater stability of the oxygen sensitive NifA protein. This conclusion was further substantiated by measuring the levels of NifA protein and its activity in fnr deletion strains in comparison with the wild-type. CONCLUSIONS Fnr proteins are indirectly involved in controlling the activity of NifA in H. seropedicae, probably as a consequence of their influence on respiratory activity in relation to oxygen availability. Additionally we can suggest that there is some redundancy in the physiological function of the three Fnr paralogs in this organism, since altered respiration and effects on NifA activity are only observed in deletion strains lacking both fnr1 and fnr3.
Collapse
Affiliation(s)
- Marcelo Bueno Batista
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, P.O. Box 19046, Curitiba, PR, 81531-990, Brazil.
| | - Roseli Wassem
- Department of Genetics, Universidade Federal do Paraná, P.O. Box 19071, Curitiba, PR, 81531-990, Brazil.
| | - Fábio de Oliveira Pedrosa
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, P.O. Box 19046, Curitiba, PR, 81531-990, Brazil.
| | - Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, P.O. Box 19046, Curitiba, PR, 81531-990, Brazil.
| | - Ray Dixon
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK.
| | - Rose Adele Monteiro
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, P.O. Box 19046, Curitiba, PR, 81531-990, Brazil.
| |
Collapse
|
28
|
cAMP receptor protein (CRP)-mediated resistance/tolerance in bacteria: mechanism and utilization in biotechnology. Appl Microbiol Biotechnol 2015; 99:4533-43. [DOI: 10.1007/s00253-015-6587-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/31/2015] [Accepted: 04/03/2015] [Indexed: 02/05/2023]
|
29
|
Cheng S, Karkar S, Bapteste E, Yee N, Falkowski P, Bhattacharya D. Sequence similarity network reveals the imprints of major diversification events in the evolution of microbial life. Front Ecol Evol 2014. [DOI: 10.3389/fevo.2014.00072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
|
30
|
Abstract
Campylobacter jejuni is a zoonotic Gram-negative bacterial pathogen that is exposed to reactive nitrogen species, such as nitric oxide, from a variety of sources. To combat the toxic effects of this nitrosative stress, C. jejuni upregulates a small regulon under the control of the transcriptional activator NssR, which positively regulates the expression of a single-domain globin protein (Cgb) and a truncated globin protein (Ctb). Cgb has previously been shown to detoxify nitric oxide, but the role of Ctb remains contentious. As C. jejuni is amenable to genetic manipulation, and its globin proteins are easily expressed and purified, a combination of mutagenesis, complementation, transcriptomics, spectroscopic characterisation and structural analyses has been used to probe the regulation, function and structure of Cgb and Ctb. This ability to study Cgb and Ctb with such a multi-pronged approach is a valuable asset, especially since only a small fraction of known globin proteins have been functionally characterised.
Collapse
|