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Leucine-Responsive Regulatory Protein in Acetic Acid Bacteria Is Stable and Functions at a Wide Range of Intracellular pH Levels. J Bacteriol 2021; 203:e0016221. [PMID: 34228496 DOI: 10.1128/jb.00162-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acetic acid bacteria grow while producing acetic acid, resulting in acidification of the culture. Limited reports elucidate the effect of changes in intracellular pH on transcriptional factors. In the present study, the intracellular pH of Komagataeibacter europaeus was monitored with a pH-sensitive green fluorescent protein, showing that the intracellular pH decreased from 6.3 to 4.7 accompanied by acetic acid production during cell growth. The leucine-responsive regulatory protein of K. europaeus (KeLrp) was used as a model to examine pH-dependent effects, and its properties were compared with those of the Escherichia coli ortholog (EcLrp) at different pH levels. The DNA-binding activities of EcLrp and KeLrp with the target DNA (Ec-ilvI and Ke-ilvI) were examined by gel mobility shift assays under various pH conditions. EcLrp showed the highest affinity with the target at pH 8.0 (Kd [dissociation constant], 0.7 μM), decreasing to a minimum of 3.4 μM at pH 4.0. Conversely, KeLrp did not show significant differences in binding affinity between pH 4 and 7 (Kd, 1.0 to 1.5 μM), and the highest affinity was at pH 5.0 (Kd, 1.0 μM). Circular dichroism spectroscopy revealed that the α-helical content of KeLrp was the highest at pH 5.0 (49%) and was almost unchanged while being maintained at >45% over a range of pH levels examined, while that of EcLrp decreased from its maximum (49% at pH 7.0) to its minimum (36% at pH 4.0). These data indicate that KeLrp is stable and functions over a wide range of intracellular pH levels. IMPORTANCE Lrp is a highly conserved transcriptional regulator found in bacteria and archaea and regulates transcriptions of various genes. The intracellular pH of acetic acid bacteria (AAB) changes accompanied by acetic acid production during cell growth. The Lrp of AAB K. europaeus (KeLrp) was structurally stable over a wide range of pH and maintained DNA-binding activity even at low pH compared with Lrp from E. coli living in a neutral environment. An in vitro experiment showed DNA-binding activity of KeLrp to the target varied with changes in pH. In AAB, change of the intracellular pH during a cell growth would be an important trigger in controlling the activity of Lrp in vivo.
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Ziegler CA, Freddolino PL. The leucine-responsive regulatory proteins/feast-famine regulatory proteins: an ancient and complex class of transcriptional regulators in bacteria and archaea. Crit Rev Biochem Mol Biol 2021; 56:373-400. [PMID: 34151666 DOI: 10.1080/10409238.2021.1925215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Since the discovery of the Escherichia coli leucine-responsive regulatory protein (Lrp) almost 50 years ago, hundreds of Lrp homologs have been discovered, occurring in 45% of sequenced bacteria and almost all sequenced archaea. Lrp-like proteins are often referred to as the feast/famine regulatory proteins (FFRPs), reflecting their common regulatory roles. Acting as either global or local transcriptional regulators, FFRPs detect the environmental nutritional status by sensing small effector molecules (usually amino acids) and regulate the expression of genes involved in metabolism, virulence, motility, nutrient transport, stress tolerance, and antibiotic resistance to implement appropriate behaviors for the specific ecological niche of each organism. Despite FFRPs' complexity, a significant role in gene regulation, and prevalence throughout prokaryotes, the last comprehensive review on this family of proteins was published about a decade ago. In this review, we integrate recent notable findings regarding E. coli Lrp and other FFRPs across bacteria and archaea with previous observations to synthesize a more complete view on the mechanistic details and biological roles of this ancient class of transcription factors.
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Affiliation(s)
- Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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Ali F, Seshasayee ASN. Dynamics of genetic variation in transcription factors and its implications for the evolution of regulatory networks in Bacteria. Nucleic Acids Res 2020; 48:4100-4114. [PMID: 32182360 PMCID: PMC7192604 DOI: 10.1093/nar/gkaa162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 02/05/2020] [Accepted: 03/03/2020] [Indexed: 11/25/2022] Open
Abstract
The evolution of regulatory networks in Bacteria has largely been explained at macroevolutionary scales through lateral gene transfer and gene duplication. Transcription factors (TF) have been found to be less conserved across species than their target genes (TG). This would be expected if TFs accumulate mutations faster than TGs. This hypothesis is supported by several lab evolution studies which found TFs, especially global regulators, to be frequently mutated. Despite these studies, the contribution of point mutations in TFs to the evolution of regulatory network is poorly understood. We tested if TFs show greater genetic variation than their TGs using whole-genome sequencing data from a large collection of Escherichia coli isolates. TFs were less diverse than their TGs across natural isolates, with TFs of large regulons being more conserved. In contrast, TFs showed higher mutation frequency in adaptive laboratory evolution experiments. However, over long-term laboratory evolution spanning 60 000 generations, mutation frequency in TFs gradually declined after a rapid initial burst. Extrapolating the dynamics of genetic variation from long-term laboratory evolution to natural populations, we propose that point mutations, conferring large-scale gene expression changes, may drive the early stages of adaptation but gene regulation is subjected to stronger purifying selection post adaptation.
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Affiliation(s)
- Farhan Ali
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, Karnataka 560065, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Aswin Sai Narain Seshasayee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, Karnataka 560065, India
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The ilvGMEDA Operon Is Regulated by Transcription Attenuation in Vibrio alginolyticus ZJ-T. Appl Environ Microbiol 2019; 85:AEM.00880-19. [PMID: 31324637 DOI: 10.1128/aem.00880-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/16/2019] [Indexed: 11/20/2022] Open
Abstract
Bacteria synthesize amino acids according to their availability in the environment or, in the case of pathogens, within the host. We explored the regulation of the biosynthesis of branched-chain amino acids (BCAAs) (l-leucine, l-valine, and l-isoleucine) in Vibrio alginolyticus, a marine fish and shellfish pathogen and an emerging opportunistic human pathogen. In this species, the ilvGMEDA operon encodes the main pathway for biosynthesis of BCAAs. Its upstream regulatory region shows no sequence similarity to the corresponding region in Escherichia coli or other Enterobacteriaceae, and yet we show that this operon is regulated by transcription attenuation. The translation of a BCAA-rich peptide encoded upstream of the structural genes provides an adaptive response similar to the E. coli canonical model. This study of a nonmodel Gram-negative organism highlights the mechanistic conservation of transcription attenuation despite the absence of primary sequence conservation.IMPORTANCE This study analyzes the regulation of the biosynthesis of branched-chain amino acids (leucine, valine, and isoleucine) in Vibrio alginolyticus, a marine bacterium that is pathogenic to fish and humans. The results highlight the conservation of the main regulatory mechanism with that of the enterobacterium Escherichia coli, suggesting that such a mechanism appeared early during the evolution of Gram-negative bacteria, allowing adaptation to a wide range of environments.
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Characterization and engineering of the Lrp/AsnC family regulator SACE_5717 for erythromycin overproduction in Saccharopolyspora erythraea. J Ind Microbiol Biotechnol 2019; 46:1013-1024. [PMID: 31016583 DOI: 10.1007/s10295-019-02178-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/04/2019] [Indexed: 10/27/2022]
Abstract
In this work, we found that the Lrp/AsnC family protein SACE_5717 negatively regulated erythromycin biosynthesis in S. erythraea. Disruption of SACE_5717 led to a 27% improvement in the yield of erythromycin in S. erythraea A226. SACE_5717 directly repressed its own gene expression, as well as that of the adjacent gene SACE_5716 by binding to the target sequence 5'-GAACGTTCGCCGTCACGCC-3'. The predicted LysE superfamily protein SACE_5716 directly influenced the export of lysine, histidine, threonine and glycine in S. erythraea. Arginine, tyrosine and tryptophan were characterized as the effectors of SACE_5717 by weakening the binding affinity of SACE_5717. In the industrial S. erythraea WB strain, deletion of SACE_5717 (WBΔSACE_5717) increased erythromycin yield by 20%, and by 36% when SACE_5716 was overexpressed in WBΔSACE_5717 (WBΔSACE_5717/5716). In large-scale 5-L fermentation experiment, erythromycin yield in the engineered strain WBΔSACE_5717/5716 reached 4686 mg/L, a 41% enhancement over 3323 mg/L of the parent WB strain.
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Ciaccia PN, Ramachandran R, Chattoraj DK. A Requirement for Global Transcription Factor Lrp in Licensing Replication of Vibrio cholerae Chromosome 2. Front Microbiol 2018; 9:2103. [PMID: 30250457 PMCID: PMC6139311 DOI: 10.3389/fmicb.2018.02103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/20/2018] [Indexed: 12/28/2022] Open
Abstract
The human pathogen, Vibrio cholerae, belongs to the 10% of bacteria in which the genome is divided. Each of its two chromosomes, like bacterial chromosomes in general, replicates from a unique origin at fixed times in the cell cycle. Chr1 initiates first, and upon duplication of a site in Chr1, crtS, Chr2 replication initiates. Recent in vivo experiments demonstrate that crtS binds the Chr2-specific initiator RctB and promotes its initiator activity by remodeling it. Compared to the well-defined RctB binding sites in the Chr2 origin, crtS is an order of magnitude longer, suggesting that other factors can bind to it. We developed an in vivo screen to identify additional crtS-binding proteins and identified the global transcription factor, Lrp, as one such protein. Studies in vivo and in vitro indicate that Lrp binds to crtS and facilitates RctB binding to crtS. Chr2 replication is severely defective in the absence of Lrp, indicative of a critical role of the transcription factor in licensing Chr2 replication. Since Lrp responds to stresses such as nutrient limitation, its interaction with RctB presumably sensitizes Chr2 replication to the physiological state of the cell.
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Affiliation(s)
| | - Revathy Ramachandran
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
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Liu J, Li J, Dong H, Chen Y, Wang Y, Wu H, Li C, Weaver DT, Zhang L, Zhang B. Characterization of an Lrp/AsnC family regulator SCO3361, controlling actinorhodin production and morphological development in Streptomyces coelicolor. Appl Microbiol Biotechnol 2017; 101:5773-5783. [DOI: 10.1007/s00253-017-8339-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/06/2017] [Accepted: 05/09/2017] [Indexed: 10/19/2022]
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Liu J, Chen Y, Wang W, Ren M, Wu P, Wang Y, Li C, Zhang L, Wu H, Weaver DT, Zhang B. Engineering of an Lrp family regulator SACE_Lrp improves erythromycin production in Saccharopolyspora erythraea. Metab Eng 2017; 39:29-37. [DOI: 10.1016/j.ymben.2016.10.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/05/2016] [Accepted: 10/25/2016] [Indexed: 01/09/2023]
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Abstract
Proteus mirabilis is a Gram-negative bacterium and is well known for its ability to robustly swarm across surfaces in a striking bulls'-eye pattern. Clinically, this organism is most frequently a pathogen of the urinary tract, particularly in patients undergoing long-term catheterization. This review covers P. mirabilis with a focus on urinary tract infections (UTI), including disease models, vaccine development efforts, and clinical perspectives. Flagella-mediated motility, both swimming and swarming, is a central facet of this organism. The regulation of this complex process and its contribution to virulence is discussed, along with the type VI-secretion system-dependent intra-strain competition, which occurs during swarming. P. mirabilis uses a diverse set of virulence factors to access and colonize the host urinary tract, including urease and stone formation, fimbriae and other adhesins, iron and zinc acquisition, proteases and toxins, biofilm formation, and regulation of pathogenesis. While significant advances in this field have been made, challenges remain to combatting complicated UTI and deciphering P. mirabilis pathogenesis.
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Unoarumhi Y, Blumenthal RM, Matson JS. Evolution of a global regulator: Lrp in four orders of γ-Proteobacteria. BMC Evol Biol 2016; 16:111. [PMID: 27206730 PMCID: PMC4875751 DOI: 10.1186/s12862-016-0685-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/12/2016] [Indexed: 11/11/2022] Open
Abstract
Background Bacterial global regulators each regulate the expression of several hundred genes. In Escherichia coli, the top seven global regulators together control over half of all genes. Leucine-responsive regulatory protein (Lrp) is one of these top seven global regulators. Lrp orthologs are very widely distributed, among both Bacteria and Archaea. Surprisingly, even within the phylum γ-Proteobacteria (which includes E. coli), Lrp is a global regulator in some orders and a local regulator in others. This raises questions about the evolution of Lrp and, more broadly, of global regulators. Results We examined Lrp sequences from four bacterial orders of the γ-Proteobacteria using phylogenetic and Logo analyses. The orders studied were Enterobacteriales and Vibrionales, in which Lrp plays a global role in tested species; Pasteurellales, in which Lrp is a local regulator in the tested species; and Alteromonadales, an order closely related to the other three but in which Lrp has not yet been studied. For comparison, we analyzed the Lrp paralog AsnC, which in all tested cases is a local regulator. The Lrp and AsnC phylogenetic clusters each divided, as expected, into subclusters representing the Enterobacteriales, Vibrionales, and Pasteuralles. However the Alteromonadales did not yield coherent clusters for either Lrp or AsnC. Logo analysis revealed signatures associated with globally- vs. locally- acting Lrp orthologs, providing testable hypotheses for which portions of Lrp are responsible for a global vs. local role. These candidate regions include both ends of the Lrp polypeptide but not, interestingly, the highly-conserved helix-turn-helix motif responsible for DNA sequence specificity. Conclusions Lrp and AsnC have conserved sequence signatures that allow their unambiguous annotation, at least in γ-Proteobacteria. Among Lrp orthologs, specific residues correlated with global vs. local regulatory roles, and can now be tested to determine which are functionally relevant and which simply reflect divergence. In the Alteromonadales, it appears that there are different subgroups of Lrp orthologs, one of which may act globally while the other may act locally. These results suggest experiments to improve our understanding of the evolution of bacterial global regulators. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0685-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yvette Unoarumhi
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.,Program in Bioinformatics and Proteomics/Genomics, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.,Program in Bioinformatics and Proteomics/Genomics, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Jyl S Matson
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.
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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: 48] [Impact Index Per Article: 6.0] [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.
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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
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Chen C, Li Y, Hu J, Dong X, Wang X. Metabolic engineering of Corynebacterium glutamicum ATCC13869 for l-valine production. Metab Eng 2015; 29:66-75. [DOI: 10.1016/j.ymben.2015.03.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 11/28/2022]
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Mahdi LK, Deihimi T, Zamansani F, Fruzangohar M, Adelson DL, Paton JC, Ogunniyi AD, Ebrahimie E. A functional genomics catalogue of activated transcription factors during pathogenesis of pneumococcal disease. BMC Genomics 2014; 15:769. [PMID: 25196724 PMCID: PMC4171566 DOI: 10.1186/1471-2164-15-769] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/03/2014] [Indexed: 11/11/2022] Open
Abstract
Background Streptococcus pneumoniae (the pneumococcus) is the world’s foremost microbial pathogen, killing more people each year than HIV, TB or malaria. The capacity to penetrate deeper host tissues contributes substantially to the ability of this organism to cause disease. Here we investigated, for the first time, functional genomics modulation of 3 pneumococcal strains (serotype 2 [D39], serotype 4 [WCH43] and serotype 6A [WCH16]) during transition from the nasopharynx to lungs to blood and to brain of mice at both promoter and domain activation levels. Results We found 7 highly activated transcription factors (TFs) [argR, codY, hup, rpoD, rr02, scrR and smrC] capable of binding to a large number of up-regulated genes, potentially constituting the regulatory backbone of pneumococcal pathogenesis. Strain D39 showed a distinct profile in employing a large number of TFs during blood infection. Interestingly, the same highly activated TFs used by D39 in blood are also used by WCH16 and WCH43 during brain infection. This indicates that different pneumococcal strains might activate a similar set of TFs and regulatory elements depending on the final site of infection. Hierarchical clustering analysis showed that all the highly activated TFs, except rpoD, clustered together with a high level of similarity in all 3 strains, which might suggest redundancy in the regulatory roles of these TFs during infection. Discriminant function analysis of the TFs in various niches highlights differential regulatory backgrounds of the 3 strains, and pathogenesis data confirms codY as the most significant predictor discriminating between these strains in various niches, particularly in the blood. Moreover, the predicted TF and domain activation profiles of the 3 strains correspond with their distinct pathogenicity characteristics. Conclusions Our findings suggest that the pneumococcus changes the short binding sites in the promoter regions of genes in a niche-specific manner to enhance its ability to disseminate from one host niche to another. This study provides a framework for an improved understanding of the dynamics of pneumococcal pathogenesis, and opens a new avenue into similar investigations in other pathogenic bacteria. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-769) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Abiodun D Ogunniyi
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia.
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A secondary structure in the 5' untranslated region of adhE mRNA required for RNase G-dependent regulation. Biosci Biotechnol Biochem 2013; 77:2473-9. [PMID: 24317071 DOI: 10.1271/bbb.130618] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Escherichia coli RNase G is involved in the degradation of several mRNAs, including adhE and eno, which encode alcohol dehydrogenase and enolase respectively. Previous research indicates that the 5' untranslated region (5'-UTR) of adhE mRNA gives RNase G-dependency to lacZ mRNA when tagged at the 5'-end, but it has not been elucidated yet how RNase G recognizes adhE mRNA. Primer extension analysis revealed that RNase G cleaved a phosphodiester bond between -19A and -18C in the 5'-UTR (the A of the start codon was defined as +1). Site-directed mutagenesis indicated that RNase G did not recognize the nucleotides at -19 and -18. Random deletion analysis indicated that the sequence from -145 to -125 was required for RNase G-dependent degradation. Secondary structure prediction and further site-directed deletion suggested that the stem-loop structure, with a bubble in the stem, is required for RNaseG-dependent degradation of adhE mRNA.
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Acetylation of the response regulator RcsB controls transcription from a small RNA promoter. J Bacteriol 2013; 195:4174-86. [PMID: 23852870 DOI: 10.1128/jb.00383-13] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nε-lysine acetylation was recently discovered on many bacterial proteins that function in diverse cellular processes. Thus, many questions remain unanswered. For example, what mechanisms regulate lysine acetylation? Does acetylation affect physiology? To help answer these questions, we studied the Escherichia coli response regulator and transcription factor RcsB, which is reported to be acetylated in vitro. To characterize RcsB acetylation, we monitored transcription from the rprA promoter, which requires RcsB. The conventional view is that RcsB is activated by phosphorylation through either the Rcs phosphorelay or acetyl phosphate. We affirmed that rprA transcription requires phosphorylated RcsB and showed that acetyl-phosphate (AcP) is a phosphoryl group donor to RcsB. However, a mutant that accumulates AcP (ackA) exhibited a reduction in rprA transcription instead of the predicted increase. rprA transcription also diminished in the cobB mutant, which lacks the only known E. coli protein deacetylase. This suggests the existence of an inhibitory mechanism that involves lysine acetylation, a supposition supported by the observation that RcsB isolated from the ackA or cobB mutant was hyperacetylated. Finally, we used a genetic approach to identify an AckA- and CobB-sensitive lysine (Lys-154) that controls RcsB activity. We propose that acetylation inhibits RcsB activity and that some of this inhibition acts through the acetylation of Lys-154.
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Yin L, Shi F, Hu X, Chen C, Wang X. Increasing l
-isoleucine production in Corynebacterium glutamicum
by overexpressing global regulator Lrp and two-component export system BrnFE. J Appl Microbiol 2013; 114:1369-77. [DOI: 10.1111/jam.12141] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/30/2012] [Accepted: 01/11/2013] [Indexed: 11/30/2022]
Affiliation(s)
- L. Yin
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi China
- Key Laboratory of Industrial Biotechnology of Ministry of Education; School of Biotechnology; Jiangnan University; Wuxi China
| | - F. Shi
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi China
| | - X. Hu
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi China
| | - C. Chen
- Key Laboratory of Industrial Biotechnology of Ministry of Education; School of Biotechnology; Jiangnan University; Wuxi China
| | - X. Wang
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi China
- Key Laboratory of Industrial Biotechnology of Ministry of Education; School of Biotechnology; Jiangnan University; Wuxi China
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Lange C, Mustafi N, Frunzke J, Kennerknecht N, Wessel M, Bott M, Wendisch VF. Lrp of Corynebacterium glutamicum controls expression of the brnFE operon encoding the export system for l-methionine and branched-chain amino acids. J Biotechnol 2012; 158:231-41. [DOI: 10.1016/j.jbiotec.2011.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/13/2011] [Accepted: 06/01/2011] [Indexed: 11/17/2022]
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The TonB3 system in the human pathogen Vibrio vulnificus is under the control of the global regulators Lrp and cyclic AMP receptor protein. J Bacteriol 2012; 194:1897-911. [PMID: 22307757 DOI: 10.1128/jb.06614-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
TonB systems transduce the proton motive force of the cytoplasmic membrane to energize substrate transport through a specific TonB-dependent transporter across the outer membrane. Vibrio vulnificus, an opportunistic marine pathogen that can cause a fatal septicemic disease in humans and eels, possesses three TonB systems. While the TonB1 and TonB2 systems are iron regulated, the TonB3 system is induced when the bacterium grows in human serum. In this work we have determined the essential roles of the leucine-responsive protein (Lrp) and cyclic AMP (cAMP) receptor protein (CRP) in the transcriptional activation of this system. Whereas Lrp shows at least four very distinctive DNA binding regions spread out from position -59 to -509, cAMP-CRP binds exclusively in a region centered at position -122.5 from the start point of the transcription. Our results suggest that both proteins bind simultaneously to the region closer to the RNA polymerase binding site. Importantly, we report that the TonB3 system is induced not only by serum but also during growth in minimal medium with glycerol as the sole carbon source and low concentrations of Casamino Acids. In addition to catabolite repression by glucose, l-leucine acts by inhibiting the binding of Lrp to the promoter region, hence preventing transcription of the TonB3 operon. Thus, this TonB system is under the direct control of two global regulators that can integrate different environmental signals (i.e., glucose starvation and the transition between "feast" and "famine"). These results shed light on new mechanisms of regulation for a TonB system that could be widespread in other organisms.
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Recognition of DNA by the helix-turn-helix global regulatory protein Lrp is modulated by the amino terminus. J Bacteriol 2011; 193:3794-803. [PMID: 21642464 DOI: 10.1128/jb.00191-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The AsnC/Lrp family of regulatory proteins links bacterial and archaeal transcription patterns to metabolism. In Escherichia coli, Lrp regulates approximately 400 genes, over 200 of them directly. In earlier studies, lrp genes from Vibrio cholerae, Proteus mirabilis, and E. coli were introduced into the same E. coli background and yielded overlapping but significantly different regulons. These differences were seen despite amino acid sequence identities of 92% (Vibrio) and 98% (Proteus) to E. coli Lrp, including complete conservation of the helix-turn-helix motifs. The N-terminal region contains many of the sequence differences among these Lrp orthologs, which led us to investigate its role in Lrp function. Through the generation of hybrid proteins, we found that the N-terminal diversity is responsible for some of the differences between orthologs in terms of DNA binding (as revealed by mobility shift assays) and multimerization (as revealed by gel filtration, dynamic light scattering, and analytical ultracentrifugation). These observations indicate that the N-terminal tail plays a significant role in modulating Lrp function, similar to what is seen for a number of other regulatory proteins.
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Ferenci T, Galbiati HF, Betteridge T, Phan K, Spira B. The constancy of global regulation across a species: the concentrations of ppGpp and RpoS are strain-specific in Escherichia coli. BMC Microbiol 2011; 11:62. [PMID: 21439067 PMCID: PMC3074542 DOI: 10.1186/1471-2180-11-62] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 03/25/2011] [Indexed: 12/21/2022] Open
Abstract
Background Sigma factors and the alarmone ppGpp control the allocation of RNA polymerase to promoters under stressful conditions. Both ppGpp and the sigma factor σS (RpoS) are potentially subject to variability across the species Escherichia coli. To find out the extent of strain variation we measured the level of RpoS and ppGpp using 31 E. coli strains from the ECOR collection and one reference K-12 strain. Results Nine ECORs had highly deleterious mutations in rpoS, 12 had RpoS protein up to 7-fold above that of the reference strain MG1655 and the remainder had comparable or lower levels. Strain variation was also evident in ppGpp accumulation under carbon starvation and spoT mutations were present in several low-ppGpp strains. Three relationships between RpoS and ppGpp levels were found: isolates with zero RpoS but various ppGpp levels, strains where RpoS levels were proportional to ppGpp and a third unexpected class in which RpoS was present but not proportional to ppGpp concentration. High-RpoS and high-ppGpp strains accumulated rpoS mutations under nutrient limitation, providing a source of polymorphisms. Conclusions The ppGpp and σS variance means that the expression of genes involved in translation, stress and other traits affected by ppGpp and/or RpoS are likely to be strain-specific and suggest that influential components of regulatory networks are frequently reset by microevolution. Different strains of E. coli have different relationships between ppGpp and RpoS levels and only some exhibit a proportionality between increasing ppGpp and RpoS levels as demonstrated for E. coli K-12.
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Affiliation(s)
- Thomas Ferenci
- School of Molecular and Microbial Biosciences, The University of Sydney, NSW, Australia
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Unexpected coregulator range for the global regulator Lrp of Escherichia coli and Proteus mirabilis. J Bacteriol 2010; 193:1054-64. [PMID: 21169483 DOI: 10.1128/jb.01183-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Lrp/AsnC family of transcription factors links gene regulation to metabolism in bacteria and archaea. Members of this family, collectively, respond to a wide range of amino acids as coregulators. In Escherichia coli, Lrp regulates over 200 genes directly and is well known to respond to leucine and, to a somewhat lesser extent, alanine. We focused on Lrp from Proteus mirabilis and E. coli, orthologs with 98% identity overall and identical helix-turn-helix motifs, for which a previous study nevertheless found functional differences. Sequence differences between these orthologs, within and adjacent to the amino acid-responsive RAM domain, led us to test for differential sensitivity to coregulatory amino acids. In the course of this investigation, we found, via in vivo reporter fusion assays and in vitro electrophoretic mobility shift experiments, that E. coli Lrp itself responded to a broader range of amino acids than was previously appreciated. In particular, for both the E. coli and P. mirabilis orthologs, Lrp responsiveness to methionine was similar in magnitude to that to leucine. Both Lrp orthologs are also fairly sensitive to Ile, His, and Thr. These observations suggest that Lrp ties gene expression in the Enterobacteriaceae rather extensively to physiological status, as reflected in amino acid pools. These findings also have substantial implications for attempts to model regulatory architecture from transcriptome measurements or to infer such architecture from genome sequences, and they suggest that even well-studied regulators deserve ongoing exploration.
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Morgenstein RM, Szostek B, Rather PN. Regulation of gene expression during swarmer cell differentiation in Proteus mirabilis. FEMS Microbiol Rev 2010; 34:753-63. [PMID: 20497230 DOI: 10.1111/j.1574-6976.2010.00229.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The gram-negative bacterium Proteus mirabilis can exist in either of two cell types, a vegetative cell characterized as a short rod and a highly elongated and hyperflagellated swarmer cell. This differentiation is triggered by growth on solid surfaces and multiple inputs are sensed by the cell to initiate the differentiation process. These include the inhibition of flagellar rotation, the accumulation of extracellular putrescine and O-antigen interactions with a surface. A key event in the differentiation process is the upregulation of FlhD(2)C(2), which activates the flagellar regulon and additional genes required for differentiation. There are a number of genes that influence FlhD(2)C(2) expression and the function of these genes, if known, will be discussed in this review. Additional genes that have been shown to regulate gene expression during swarming will also be reviewed. Although P. mirabilis represents an excellent system to study microbial differentiation, it is largely understudied relative to other systems. Therefore, this review will also discuss some of the unanswered questions that are central to understanding this process in P. mirabilis.
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Affiliation(s)
- Randy M Morgenstein
- Department of Microbiology and Immunology, 3001 Rollins Research Center, Emory University, Atlanta, GA 30322, USA
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Subashchandrabose S, LeVeque RM, Wagner TK, Kirkwood RN, Kiupel M, Mulks MH. Branched-chain amino acids are required for the survival and virulence of Actinobacillus pleuropneumoniae in swine. Infect Immun 2009; 77:4925-33. [PMID: 19703979 PMCID: PMC2772520 DOI: 10.1128/iai.00671-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 07/01/2009] [Accepted: 08/17/2009] [Indexed: 11/20/2022] Open
Abstract
In Actinobacillus pleuropneumoniae, which causes porcine pleuropneumonia, ilvI was identified as an in vivo-induced (ivi) gene and encodes the enzyme acetohydroxyacid synthase (AHAS) required for branched-chain amino acid (BCAA) biosynthesis. ilvI and 7 of 32 additional ivi promoters were upregulated in vitro when grown in chemically defined medium (CDM) lacking BCAA. Based on these observations, we hypothesized that BCAA would be found at limiting concentrations in pulmonary secretions and that A. pleuropneumoniae mutants unable to synthesize BCAA would be attenuated in a porcine infection model. Quantitation of free amino acids in porcine pulmonary epithelial lining fluid showed concentrations of BCAA ranging from 8 to 30 micromol/liter, which is 10 to 17% of the concentration in plasma. The expression of both ilvI and lrp, a global regulator that is required for ilvI expression, was strongly upregulated in CDM containing concentrations of BCAA similar to those found in pulmonary secretions. Deletion-disruption mutants of ilvI and lrp were both auxotrophic for BCAA in CDM and attenuated compared to wild-type A. pleuropneumoniae in competitive index experiments in a pig infection model. Wild-type A. pleuropneumoniae grew in CDM+BCAA but not in CDM-BCAA in the presence of sulfonylurea AHAS inhibitors. These results clearly demonstrate that BCAA availability is limited in the lungs and support the hypothesis that A. pleuropneumoniae, and potentially other pulmonary pathogens, uses limitation of BCAA as a cue to regulate the expression of genes required for survival and virulence. These results further suggest a potential role for AHAS inhibitors as antimicrobial agents against pulmonary pathogens.
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Affiliation(s)
- Sargurunathan Subashchandrabose
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
| | - Rhiannon M. LeVeque
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
| | - Trevor K. Wagner
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
| | - Roy N. Kirkwood
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
| | - Matti Kiupel
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
| | - Martha H. Mulks
- Comparative Medicine and Integrative Biology Program, Department of Microbiology and Molecular Genetics, Department of Large Animal Clinical Sciences, Department of Pathobiology and Diagnostic Investigation, Center for Microbial Pathogenesis, Michigan State University, East Lansing, Michigan 48824
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van Hijum SAFT, Medema MH, Kuipers OP. Mechanisms and evolution of control logic in prokaryotic transcriptional regulation. Microbiol Mol Biol Rev 2009; 73:481-509, Table of Contents. [PMID: 19721087 PMCID: PMC2738135 DOI: 10.1128/mmbr.00037-08] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major part of organismal complexity and versatility of prokaryotes resides in their ability to fine-tune gene expression to adequately respond to internal and external stimuli. Evolution has been very innovative in creating intricate mechanisms by which different regulatory signals operate and interact at promoters to drive gene expression. The regulation of target gene expression by transcription factors (TFs) is governed by control logic brought about by the interaction of regulators with TF binding sites (TFBSs) in cis-regulatory regions. A factor that in large part determines the strength of the response of a target to a given TF is motif stringency, the extent to which the TFBS fits the optimal TFBS sequence for a given TF. Advances in high-throughput technologies and computational genomics allow reconstruction of transcriptional regulatory networks in silico. To optimize the prediction of transcriptional regulatory networks, i.e., to separate direct regulation from indirect regulation, a thorough understanding of the control logic underlying the regulation of gene expression is required. This review summarizes the state of the art of the elements that determine the functionality of TFBSs by focusing on the molecular biological mechanisms and evolutionary origins of cis-regulatory regions.
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Affiliation(s)
- Sacha A F T van Hijum
- Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.
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Abstract
Related organisms typically respond to a given cue by altering the level or activity of orthologous transcription factors, which, paradoxically, often regulate expression of distinct gene sets. Although promoter rewiring of shared genes is primarily responsible for regulatory differences among related eukaryotic species, in bacteria, species-specific genes are often controlled by ancestral transcription factors, and regulatory circuit evolution has been further shaped by horizontal gene transfer. Modifications in transcription factors and in promoter structure also contribute to divergence in bacterial regulatory circuits.
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Balleza E, López-Bojorquez LN, Martínez-Antonio A, Resendis-Antonio O, Lozada-Chávez I, Balderas-Martínez YI, Encarnación S, Collado-Vides J. Regulation by transcription factors in bacteria: beyond description. FEMS Microbiol Rev 2009; 33:133-51. [PMID: 19076632 PMCID: PMC2704942 DOI: 10.1111/j.1574-6976.2008.00145.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Transcription is an essential step in gene expression and its understanding has been one of the major interests in molecular and cellular biology. By precisely tuning gene expression, transcriptional regulation determines the molecular machinery for developmental plasticity, homeostasis and adaptation. In this review, we transmit the main ideas or concepts behind regulation by transcription factors and give just enough examples to sustain these main ideas, thus avoiding a classical ennumeration of facts. We review recent concepts and developments: cis elements and trans regulatory factors, chromosome organization and structure, transcriptional regulatory networks (TRNs) and transcriptomics. We also summarize new important discoveries that will probably affect the direction of research in gene regulation: epigenetics and stochasticity in transcriptional regulation, synthetic circuits and plasticity and evolution of TRNs. Many of the new discoveries in gene regulation are not extensively tested with wetlab approaches. Consequently, we review this broad area in Inference of TRNs and Dynamical Models of TRNs. Finally, we have stepped backwards to trace the origins of these modern concepts, synthesizing their history in a timeline schema.
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Affiliation(s)
- Enrique Balleza
- Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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