1
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Qu S, Dai H. Conjugated STING agonists. MOLECULAR THERAPY. NUCLEIC ACIDS 2025; 36:102530. [PMID: 40291379 PMCID: PMC12032345 DOI: 10.1016/j.omtn.2025.102530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/30/2025]
Abstract
An innate immune system is the first line of defense and prevents the host from infection and attacks the invading pathogens. Stimulator of interferon genes (STING) plays a vital role in the innate immune system. STING activation by STING agonists leads to phosphorylation of TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3) with the release of type I interferons and proinflammatory cytokines, further promoting the adaptive immune response and activating T cells by increased antigen presentation. Natural STING agonist cyclic dinucleotides (CDNs) encounter many defects such as high polarity by negative charges, low stability and circulative half-life, off-target systemic toxicity, and low response efficacy in clinical trials. To overcome these challenges, massive efforts have addressed chemical modifications of CDNs, development of non-CDN STING agonists, and delivery of these STING agonists either by conjugation or liposomes/nanoparticles. Considering there have been a great number of reports regarding nanosystem-aided delivery, here, we examine the development of STING agonists, especially for non-CDNs and their delivery specifically by conjugation strategy, with a focus on the STING agonists in clinical trials and current challenges of their potential in cancer immunotherapy.
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Affiliation(s)
- Shuhao Qu
- School of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, China
| | - Hong Dai
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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2
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Chaudhury SN, Jespersen NE, Hennelly SP, Sanbonmatsu KY. Regulatory helix plays a key role in genetic ON-OFF switching for the 2'-deoxyguanosine sensing mRNA element. J Biol Chem 2025:110282. [PMID: 40412519 DOI: 10.1016/j.jbc.2025.110282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2024] [Revised: 05/09/2025] [Accepted: 05/20/2025] [Indexed: 05/27/2025] Open
Abstract
Transcriptional riboswitches, noncoding mRNA elements that operate in cis to regulate gene expression, have a promising potential in medicine, synthetic biology and directed evolution. They bind to cellular metabolites or metal ions with high specificity, leading to conformational rearrangements that facilitate the activation or premature termination of transcription for downstream genes. This elegant mechanism for feedback regulation of metabolic pathways has been identified in prokaryotes and a few in eukaryotes. Our chemical probing of the 2'-deoxyguanosine (2'-dG)-sensing riboswitch demonstrates that the overall conformational state of the full-length riboswitch (dGsw-fl) is unresponsive to the 2'-dG. Although binding proceeds as expected, dGsw-fl exclusively populates an OFF state of transcriptional inhibition. We chemically probed the structure of a known dGsw transcriptional intermediate (dGsw-int) to evaluate the possibility of a cotranscriptional regulatory role. Interestingly, apo dGsw-int adopts an alternative conformation in which a stable anti-terminator helix is formed, leading to an ON state where transcription can proceed. In the presence of 2'-dG, this anti-terminator helix is destabilized to produce a conformation reminiscent of the full-length, OFF-state dGsw. Using a fluorescence quenching assay, we demonstrate that binding 2'-dG to early transcriptional intermediates can inhibit the formation of the anti-terminator helix, locking dGsw in an OFF state. These data suggest that metabolite sensing occurs during a brief window of time between the synthesis of two transcriptional intermediates. Our studies indicate that dGsw does not function as a binary ON-OFF switch, but instead fine-tunes the transcription of downstream genes during RNA synthesis using key intermediates.
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Affiliation(s)
- Susmit Narayan Chaudhury
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
| | - Nathan Edward Jespersen
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
| | - Scott P Hennelly
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, United States; New Mexico Consortium, Los Alamos, NM 87544, United States.
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3
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Xiao W, Liu G, Chen T, Zhang Y, Ke A, Cai R, Lu C. Escherichia coli yybP-ykoY Riboswitch as a Tandem Riboswitch Regulated by Mn 2+ and pH. ACS Chem Biol 2025; 20:1010-1019. [PMID: 40252020 DOI: 10.1021/acschembio.4c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2025]
Abstract
The Escherichiacoli yybP-ykoY riboswitch regulates mntP and alx gene expression on the translation level. It contains two tandem domains regulated by Mn2+ and pH. This study investigates the tertiary structure and conformational dynamics of the E. coli yybP-ykoY riboswitch using a combination of crystallography, small-angle X-ray scattering (SAXS), and chemical probing. Our crystal structure of the aptamer domain at 3.8 Å reveals that the yybP-ykoY riboswitch aptamer domain forms a coaxial superhelix containing three helices connected by a three-way junction (3WJ), with L1 and L3 creating a pocket-like structure that binds Mg2+ and Mn2+. SHAPE probing and SAXS show that the yybP-ykoY riboswitch maintains a consistent conformation across pH conditions without Mn2+ but exhibits significant conformational changes under alkaline conditions when Mn2+ is present. These findings align with our proposed model, where Mn2+ binding induces a transition from an "OFF" to an "ON" state in alkaline conditions, while the Mn2+ remains bound to the aptamer independent of pH. This regulatory mechanism allows for more sophisticated control of gene expression, providing a finely tuned adaptive response to environmental changes.
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Affiliation(s)
- Wenwen Xiao
- College of Biological Science and Medical Engineering, Donghua University, Shanghai 201620, China
| | - Guangfeng Liu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Ting Chen
- College of Biological Science and Medical Engineering, Donghua University, Shanghai 201620, China
| | - Yunlong Zhang
- College of Biological Science and Medical Engineering, Donghua University, Shanghai 201620, China
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, United States
| | - Rujie Cai
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Changrui Lu
- College of Biological Science and Medical Engineering, Donghua University, Shanghai 201620, China
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4
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Barth KM, Hiller DA, Belem de Andrade G, Kavita K, Fernando CM, Breaker RR, Strobel SA. Decoding the Complex Functional Landscape of the ykkC Riboswitches. Biochemistry 2025; 64:1983-1995. [PMID: 40254862 DOI: 10.1021/acs.biochem.4c00787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2025]
Abstract
The ykkC class is the most diverse riboswitch class to date, recognizing structurally and chemically diverse ligands using only minor changes in sequence and structure. Structural studies have demonstrated how sequence changes correspond to altered specificity; however, they are insufficient to define the requirements for functional riboswitch specificity. Here, we report an extensive mutational analysis of the ppGpp riboswitch to investigate the functional role in transcriptional control for this variant riboswitch. Disruption of the terminator hairpin at a single base pair is sufficient to abolish nearly all function, highlighting the fine-tuning of the terminator hairpin to its corresponding aptamer domain. This fine-tuning has been observed in other riboswitches, suggesting that high levels of tunability may be a common feature of riboswitches. Additionally, mutational analysis shows that the previously reported binding site position, G93, does not necessarily correspond to PRPP-driven function as expected. Phylogenetic analysis of natural riboswitches that contain G93 revealed an additional ykkC subclass that binds to both XMP and GMP. This variant subclass is associated with genes for de novo GMP synthesis. Identification of this variant class provides further evidence for small sequence changes corresponding to altered ligand specificity.
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Affiliation(s)
- Kathryn M Barth
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, United States
| | - David A Hiller
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, United States
| | - Gabriel Belem de Andrade
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - Chrishan M Fernando
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, United States
| | - Ronald R Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, United States
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06511, United States
| | - Scott A Strobel
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, Connecticut 06516, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, United States
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5
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Ghasemi A, Yuan X, Yang CH. A novel transcriptional regulator, CdeR, modulates the type III secretion system via c-di-GMP signaling in Dickeya dadantii. Microbiol Spectr 2025; 13:e0265524. [PMID: 40042333 PMCID: PMC11960120 DOI: 10.1128/spectrum.02655-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2024] [Accepted: 02/05/2025] [Indexed: 04/03/2025] Open
Abstract
Dickeya dadantii is a bacterial pathogen that causes soft rot disease in many plant species worldwide, including temperate, subtropical, and tropical regions. This bacterium employs the type III secretion system (T3SS) to manipulate host immune responses. Although cyclic-di-GMP (c-di-GMP), a ubiquitous bacterial second messenger, negatively regulates the expression of T3SS genes in D. dadantii, the underlying mechanism remains unclear. In this study, we identified a potential transcriptional regulator, CdeR, which regulates the T3SS involving c-di-GMP. Through transposon mutagenesis, we discovered that deletion of cdeR in a gcpD mutant background restored T3SS gene expression. GcpD is a diguanylate cyclase responsible for c-di-GMP synthesis, and its deletion led to high T3SS gene expression due to low c-di-GMP. Further analysis revealed that, in the gcpD mutant background, CdeR regulates T3SS by manipulating intracellular c-di-GMP levels, involving another diguanylate cyclase, GcpL, whose expression is upregulated by CdeR. Additionally, we found that removing helical regions within the Helix-Turn-Helix DNA-binding domain of CdeR completely disrupted its regulation of the T3SS, underscoring the essential role of this domain in CdeR's functional activity. This study is the first to identify CdeR as a potential transcriptional regulator involved in T3SS regulation. Our findings provide significant insights into the regulatory mechanisms of T3SS and highlight the complex interactions between bacterial second messengers and transcriptional regulators in pathogenic bacteria.IMPORTANCEBacterial pathogens, such as Dickeya dadantii, must adapt to diverse environmental and host conditions by utilizing intricate regulatory networks to control virulence. This study identifies CdeR, a novel transcriptional regulator, as a crucial factor in modulating the expression of the type III secretion system (T3SS), a key virulence mechanism. Importantly, we show that CdeR operates in a cyclic-di-GMP (c-di-GMP)-dependent manner, linking this second messenger to T3SS regulation in D. dadantii for the first time. Our findings reveal a sophisticated interaction between c-di-GMP signaling and transcriptional regulation, highlighting how these systems collectively drive bacterial virulence. This work advances our understanding of bacterial pathogenesis and opens new avenues for developing targeted strategies to mitigate soft rot disease in crops, potentially improving agricultural productivity and plant health.
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Affiliation(s)
- Alaleh Ghasemi
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Xiaochen Yuan
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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6
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Czerniak T, Saenz JP. Effects of lipid membranes on RNA catalytic activity and stability. Biol Cell 2025; 117:e202400115. [PMID: 40012228 PMCID: PMC11865690 DOI: 10.1111/boc.202400115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2024] [Revised: 01/28/2025] [Accepted: 01/28/2025] [Indexed: 02/28/2025]
Abstract
BACKGOUND INFORMATION RNA plays crucial roles in cellular organization and metabolism, and modulating its activity is essential for maintaining cellular functions. RNA activity, involving both catalytic (ribozymes) and translation processes, is controlled via myriad mechanisms involving different binding partners such as proteins and smaller polar solutes. We previously reported that lipid membranes can directly interact with the artificial R3C ribozyme changing its activity, however, the effect of lipids on naturally occurring ribozymes remains unknown. RESULTS Here, we report that both catalytic activity as well as RNA integrity can be controlled by the presence of different lipid membranes. Gel-phase lipid membranes decreased the activity of hepatitis delta virus ribozyme and increased the activity of a hammerhead ribozyme. The presence of lipid liquid membrane surfaces triggered RNA degradation with greater degradation occurring in the single-stranded regions of RNA. CONCLUSION The interplay between RNA activity and stability in the presence of different lipid membranes introduces multiple possibilities, where different combinations of ribozyme and lipid membrane composition could produce different effects on activity. SIGNIFICANCE Taken together, these observations support the hypothesis that the activity of both natural and artificial RNAs can be modulated by lipid membranes which, in turn, provides a foundation for the development of novel riboswitch-like molecules, and lipid membrane-based RNA-biosensors.
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Affiliation(s)
- Tomasz Czerniak
- B CUBE Center for Molecular BioengineeringTechnische Universität DresdenDresdenGermany
| | - James P. Saenz
- B CUBE Center for Molecular BioengineeringTechnische Universität DresdenDresdenGermany
- Faculty of MedicineTechnische Universität DresdenDresdenGermany
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7
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Shin JY, Choi SR, An SY, Bang KM, Song HK, Suh JY, Kim NK. Deciphering ligand and metal ion dependent intricate folding landscape of Vc2 c-di-GMP riboswitch aptamer. Nucleic Acids Res 2025; 53:gkae1296. [PMID: 39777471 PMCID: PMC11705072 DOI: 10.1093/nar/gkae1296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 12/01/2024] [Accepted: 12/26/2024] [Indexed: 01/11/2025] Open
Abstract
Riboswitches are RNAs that recognize ligands and regulate gene expression. They are typically located in the untranslated region of bacterial messenger RNA and consist of an aptamer and an expression platform. In this study, we examine the folding pathway of the Vc2 (Vibrio cholerae) riboswitch aptamer domain, which targets the bacterial secondary messenger cyclic-di-GMP. We demonstrated by nuclear magnetic resonance (NMR) and isothermal titration calorimetry that the stable folding of the Vc2 riboswitch requires an adequate supply of Mg2+, Na+ and K+ ions. We found that Mg2+ has a crucial role in the pre-folding of the aptamer, while K+ is essential for establishing the long-range G-C interactions and stabilizing the ligand binding pocket. Precise imino proton assignments revealed the progressive folding of the aptamer. The results indicate that the P2 helix consists of weaker and more dynamic base pairs compared to the P1b helix, allowing the rearrangement of the base pairs in the P2 helix during the folding process required for effective ligand recognition. This study provides a profound understanding riboswitch architecture and dynamics at the atomic level under physiological conditions as well as structural information on apo-state RNA.
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Affiliation(s)
- Ji-Yeon Shin
- Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea
- Department of Life Sciences, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Seo-Ree Choi
- Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - So Young An
- Department of Agriculture Biotechnology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Kyeong-Mi Bang
- Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea
- Department of Life Sciences, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Jeong-Yong Suh
- Department of Agriculture Biotechnology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Nak-Kyoon Kim
- Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea
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8
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Shin JH, Cuevas LM, Roy R, Bonilla SL, Al-Hashimi H, Greenleaf WJ, Herschlag D. Exploring the energetic and conformational properties of the sequence space connecting naturally occurring RNA tetraloop receptor motifs. RNA (NEW YORK, N.Y.) 2024; 30:1646-1659. [PMID: 39362695 PMCID: PMC11571812 DOI: 10.1261/rna.080039.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 09/18/2024] [Indexed: 10/05/2024]
Abstract
Folded RNAs contain tertiary contact motifs whose structures and energetics are conserved across different RNAs. The transferable properties of RNA motifs simplify the RNA folding problem, but measuring energetic and conformational properties of many motifs remains a challenge. Here, we use a high-throughput thermodynamic approach to investigate how sequence changes alter the binding properties of naturally occurring motifs, the GAAA tetraloop • tetraloop receptor (TLR) interactions. We measured the binding energies and conformational preferences of TLR sequences that span mutational pathways from the canonical 11ntR to two other natural TLRs, the IC3R and Vc2R. While the IC3R and Vc2R share highly similar energetic and conformational properties, the landscapes that map the sequence changes for their conversion from the 11ntR to changes in these properties differ dramatically. Differences in the energetic landscapes stem from the mutations needed to convert the 11ntR to the IC3R and Vc2R rather than a difference in the intrinsic energetic architectures of these TLRs. The conformational landscapes feature several nonnative TLR variants with conformational preferences that differ from both the initial and final TLRs; these species represent potential branching points along the multidimensional sequence space to sequences with greater fitness in other RNA contexts with alternative conformational preferences. Our high-throughput, quantitative approach reveals the complex nature of sequence-fitness landscapes and leads to models for their molecular origins. Systematic and quantitative molecular approaches provide critical insights into understanding the evolution of natural RNAs as they traverse complex landscapes in response to selective pressures.
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Affiliation(s)
- John H Shin
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
| | - Lena M Cuevas
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, USA
| | - Rohit Roy
- Center for Genomic and Computational Biology, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Steve L Bonilla
- Laboratory of RNA Structural Biology and Biophysics, The Rockefeller University, New York, New York 10065, USA
| | - Hashim Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA
| | - William J Greenleaf
- Department of Genetics, Stanford University, Stanford, California 94305, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
- Chan Zuckerberg Biohub, San Francisco, California 94158, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
- Chem-H Institute, Stanford University, Stanford, California 94305, USA
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9
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Samir S, Elshereef AA, Alva V, Hahn J, Dubnau D, Galperin MY, Selim KA. ComFB, a new widespread family of c-di-NMP receptor proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.11.10.622515. [PMID: 39574629 PMCID: PMC11581024 DOI: 10.1101/2024.11.10.622515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2024]
Abstract
Cyclic dimeric GMP (c-di-GMP) is a widespread bacterial second messenger that controls a variety of cellular functions, including protein and polysaccharide secretion, motility, cell division, cell development, and biofilm formation, and contributes to the virulence of some important bacterial pathogens. While the genes for diguanylate cyclases and c-di-GMP hydrolases (active or mutated) can be easily identified in microbial genomes, the list of c-di-GMP receptor domains is quite limited, and only two of them, PliZ and MshEN, are found across multiple bacterial phyla. Recently, a new c-di-GMP receptor protein, named CdgR or ComFB, has been identified in cyanobacteria and shown to regulate their cell size and, more recently, natural competence. Sequence and structural analysis indicated that CdgR is part of a widespread ComFB protein family, named after the "late competence development protein ComFB" from Bacillus subtilis. This prompted the suggestion that ComFB and ComFB-like proteins could also be c-di-GMP receptors. Indeed, we revealed that ComFB proteins from Gram-positive B. subtilis and Thermoanaerobacter brockii were able to bind c-di-GMP with high-affinity. The ability to bind c-di-GMP was also demonstrated for the ComFB proteins from clinically relevant Gram-negative bacteria Vibrio cholerae and Treponema denticola. These observations indicate that the ComFB family serves as yet another widespread family of bacterial c-di-GMP receptors. Incidentally, some ComFB proteins were also capable of c-di-AMP binding, identifying them as a unique family of c-di-NMP receptor proteins. The overexpression of comFB in B. subtilis, combined with an elevated concentration of c-di-GMP, suppressed motility, attesting to the biological relevance of ComFB as a c-di-GMP binding protein.
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Affiliation(s)
- Sherihan Samir
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence “Controlling Microbes to Fight Infections”, Eberhard Karls University of Tübingen, 72076 Tübingen, Germany
| | - Abdalla A. Elshereef
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence “Controlling Microbes to Fight Infections”, Eberhard Karls University of Tübingen, 72076 Tübingen, Germany
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, Germany
| | - Jeanette Hahn
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, New Jersey, USA
| | - David Dubnau
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, New Jersey, USA
| | - Michael Y. Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Khaled A. Selim
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence “Controlling Microbes to Fight Infections”, Eberhard Karls University of Tübingen, 72076 Tübingen, Germany
- Institute of Phototroph Microbiology, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
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10
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Ouyang Z, Zhao H, Zhao M, Yang Y, Zhao J. Type IV pili are involved in phenotypes associated with Clostridioides difficile pathogenesis. Crit Rev Microbiol 2024; 50:1011-1019. [PMID: 37452617 DOI: 10.1080/1040841x.2023.2235002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/23/2023] [Accepted: 07/05/2023] [Indexed: 07/18/2023]
Abstract
Clostridioides difficile is a Gram-positive, spore-forming, rod-shaped, obligate anaerobe that is the leading cause of antibiotic-associated diarrhea. Type IV pili (T4P) are elongated appendages on the surface of C. difficile that are polymerized from many pilin proteins. T4P play an important role in C. difficile adherence and particularly in its persistence in the host intestine. Recent studies have shown that T4P promote C. difficile aggregation, surface motility, and biofilm formation, which may enhance its pathogenicity. Additionally, the second messenger cyclic diguanylate increases pilA1 transcript abundance, indirectly promoting T4P-mediated aggregation, surface motility, and biofilm formation of C. difficile. This review summarizes recent advances in C. difficile T4P research and the physiological activities of T4P in the context of C. difficile pathogenesis.
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Affiliation(s)
- Zirou Ouyang
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang City, Hebei Province, China
| | - Hanlin Zhao
- Department of Medical Laboratory, Hebei North University, Zhangjiakou, Hebei Province, China
| | - Min Zhao
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang City, Hebei Province, China
| | - Yaxuan Yang
- School of Public Health, The University of Queensland, Brisbane, Queensland, Australia
| | - Jianhong Zhao
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang City, Hebei Province, China
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11
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Badilla Lobo A, Soutourina O, Peltier J. The current riboswitch landscape in Clostridioides difficile. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001508. [PMID: 39405103 PMCID: PMC11477304 DOI: 10.1099/mic.0.001508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Accepted: 09/26/2024] [Indexed: 10/19/2024]
Abstract
Riboswitches are 5' RNA regulatory elements that are capable of binding to various ligands, such as small metabolites, ions and tRNAs, leading to conformational changes and affecting gene transcription or translation. They are widespread in bacteria and frequently control genes that are essential for the survival or virulence of major pathogens. As a result, they represent promising targets for the development of new antimicrobial treatments. Clostridioides difficile, a leading cause of antibiotic-associated nosocomial diarrhoea in adults, possesses numerous riboswitches in its genome. Accumulating knowledge of riboswitch-based regulatory mechanisms provides insights into the potential therapeutic targets for treating C. difficile infections. This review offers an in-depth examination of the current state of knowledge regarding riboswitch-mediated regulation in C. difficile, highlighting their importance in bacterial adaptability and pathogenicity. Particular attention is given to the ligand specificity and function of known riboswitches in this bacterium. The review also discusses the recent progress that has been made in the development of riboswitch-targeting compounds as potential treatments for C. difficile infections. Future research directions are proposed, emphasizing the need for detailed structural and functional analyses of riboswitches to fully harness their regulatory capabilities for developing new antimicrobial strategies.
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Affiliation(s)
- Adriana Badilla Lobo
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Johann Peltier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
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12
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Mwangi MN, Yonkunas MJ, Ageeli AA, McGovern-Gooch KR, Yilmaz S, Baird NJ. A Newly Identified Peripheral Duplex Anchors and Stabilizes the MALAT1 Triplex. Biochemistry 2024; 63:2280-2292. [PMID: 39190685 PMCID: PMC11411715 DOI: 10.1021/acs.biochem.4c00156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 08/19/2024] [Accepted: 08/19/2024] [Indexed: 08/29/2024]
Abstract
The accumulation of the 8-kb oncogenic long noncoding MALAT1 RNA in cells is dependent on the presence of a protective triple helix structure at the 3' terminus. While recent studies have examined the functional importance of numerous base triples within the triplex and its immediately adjacent base pairs, the functional importance of peripheral duplex elements has not been thoroughly investigated. To investigate the functional importance of a peripheral linker region that was previously described as unstructured, we employed a variety of assays including thermal melting, protection from exonucleolytic degradation by RNase R, small-angle X-ray scattering, biochemical ligation and binding assays, and computational modeling. Our results demonstrate the presence of a duplex within this linker that enhances the functional stability of the triplex in vitro, despite its location more than 40 Å from the 3' terminus. We present a full-length model of the MALAT1 triple helix-containing RNA having an extended rod-like structure and comprising 33 layers of coaxial stacking interactions. Taken together with recent research on a homologous triplex, our results demonstrate that peripheral elements anchor and stabilize triplexes in vitro. Such peripheral elements may also contribute to the formation and stability of some triple helices in vivo.
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Affiliation(s)
| | | | | | | | - Sevde Yilmaz
- Department of Chemistry &
Biochemistry, Saint Joseph’s University, 600 S. 43rd Street, Philadelphia, Pennsylvania 19104, United States
| | - Nathan J. Baird
- Department of Chemistry &
Biochemistry, Saint Joseph’s University, 600 S. 43rd Street, Philadelphia, Pennsylvania 19104, United States
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13
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Ouyang Z, Zhao M, Li J, Zhang Y, Zhao J. Cyclic diguanylate differentially regulates the expression of virulence factors and pathogenesis-related phenotypes in Clostridioides difficile. Microbiol Res 2024; 286:127811. [PMID: 38909416 DOI: 10.1016/j.micres.2024.127811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 06/03/2024] [Accepted: 06/12/2024] [Indexed: 06/25/2024]
Abstract
Clostridioides difficile infection (CDI) caused by toxigenic C. difficile is the leading cause of antimicrobial and healthcare-associated diarrhea. The pathogenicity of C. difficile relies on the synergistic effect of multiple virulence factors, including spores, flagella, type IV pili (T4P), toxins, and biofilm. Spores enable survival and transmission of C. difficile, while adhesion factors such as flagella and T4P allow C. difficile to colonize and persist in the host intestine. Subsequently, C. difficile produces the toxins TcdA and TcdB, causing pseudomembranous colitis and other C. difficile-associated diseases; adhesion factors bind to the extracellular matrix to form biofilm, allowing C. difficile to evade drug and immune system attack and cause recurrent infection. Cyclic diguanylate (c-di-GMP) is a near-ubiquitous second messenger that extensively regulates morphology, the expression of virulence factors, and multiple physiological processes in C. difficile. In this review, we summarize current knowledge of how c-di-GMP differentially regulates the expression of virulence factors and pathogenesis-related phenotypes in C. difficile. We highlight that C. difficile spore formation and expression of toxin and flagella genes are inhibited at high intracellular levels of c-di-GMP, while T4P biosynthesis, cell aggregation, and biofilm formation are induced. Recent studies have enhanced our understanding of the c-di-GMP signaling networks in C. difficile and provided insights for the development of c-di-GMP-dependent strategies against CDI.
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Affiliation(s)
- Zirou Ouyang
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Min Zhao
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Jiayiren Li
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yulian Zhang
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Jianhong Zhao
- Hebei Provincial Center for Clinical Laboratories, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
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14
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Liu L, Luo D, Zhang Y, Liu D, Yin K, Tang Q, Chou SH, He J. Characterization of the dual regulation by a c-di-GMP riboswitch Bc1 with a long expression platform from Bacillus thuringiensis. Microbiol Spectr 2024; 12:e0045024. [PMID: 38819160 PMCID: PMC11218506 DOI: 10.1128/spectrum.00450-24] [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: 02/19/2024] [Accepted: 04/29/2024] [Indexed: 06/01/2024] Open
Abstract
A riboswitch generally regulates the expression of its downstream genes through conformational change in its expression platform (EP) upon ligand binding. The cyclic diguanosine monophosphate (c-di-GMP) class I riboswitch Bc1 is widespread and conserved among Bacillus cereus group species. In this study, we revealed that Bc1 has a long EP with two typical ρ-independent terminator sequences 28 bp apart. The upstream terminator T1 is dominant in vitro, while downstream terminator T2 is more efficient in vivo. Through mutation analysis, we elucidated that Bc1 exerts a rare and incoherent "transcription-translation" dual regulation with T2 playing a crucial role. However, we found that Bc1 did not respond to c-di-GMP under in vitro transcription conditions, and the expressions of downstream genes did not change with fluctuation in intracellular c-di-GMP concentration. To explore this puzzle, we conducted SHAPE-MaP and confirmed the interaction of Bc1 with c-di-GMP. This shows that as c-di-GMP concentration increases, T1 unfolds but T2 remains almost intact and functional. The presence of T2 masks the effect of T1 unwinding, resulting in no response of Bc1 to c-di-GMP. The high Shannon entropy values of EP region imply the potential alternative structures of Bc1. We also found that zinc uptake regulator can specifically bind to the dual terminator coding sequence and slightly trigger the response of Bc1 to c-di-GMP. This work will shed light on the dual-regulation riboswitch and enrich our understanding of the RNA world.IMPORTANCEIn nature, riboswitches are involved in a variety of metabolic regulation, most of which preferentially regulate transcription termination or translation initiation of downstream genes in specific ways. Alternatively, the same or different riboswitches can exist in tandem to enhance regulatory effects or respond to multiple ligands. However, many putative conserved riboswitches have not yet been experimentally validated. Here, we found that the c-di-GMP riboswitch Bc1 with a long EP could form a dual terminator and exhibit non-canonical and incoherent "transcription-translation" dual regulation. Besides, zinc uptake regulator specifically bound to the coding sequence of the Bc1 EP and slightly mediated the action of Bc1. The application of SHAPE-MaP to the dual regulation mechanism of Bc1 may establish the foundation for future studies of such complex untranslated regions in other bacterial genomes.
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Affiliation(s)
- Lu Liu
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dehua Luo
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yongji Zhang
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dingqi Liu
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Kang Yin
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qing Tang
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jin He
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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15
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Xiao W, Liu G, Chen T, Zhang Y, Lu C. Bifidobacterium bifidum SAM-VI Riboswitch Conformation Change Requires Peripheral Helix Formation. Biomolecules 2024; 14:742. [PMID: 39062457 PMCID: PMC11274715 DOI: 10.3390/biom14070742] [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: 05/11/2024] [Revised: 06/10/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
The Bifidobacterium bifidum SAM-VI riboswitch undergoes dynamic conformational changes that modulate downstream gene expression. Traditional structural methods such as crystallography capture the bound conformation at high resolution, and additional efforts would reveal details from the dynamic transition. Here, we revealed a transcription-dependent conformation model for Bifidobacterium bifidum SAM-VI riboswitch. In this study, we combine small-angle X-ray scattering, chemical probing, and isothermal titration calorimetry to unveil the ligand-binding properties and conformational changes of the Bifidobacterium bifidum SAM-VI riboswitch and its variants. Our results suggest that the SAM-VI riboswitch contains a pre-organized ligand-binding pocket and stabilizes into the bound conformation upon binding to SAM. Whether the P1 stem formed and variations in length critically influence the conformational dynamics of the SAM-VI riboswitch. Our study provides the basis for artificially engineering the riboswitch by manipulating its peripheral sequences without modifying the SAM-binding core.
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Affiliation(s)
- Wenwen Xiao
- College of Biological and Medical Engineering, Donghua University, Shanghai 201620, China; (W.X.); (T.C.); (Y.Z.)
| | - Guangfeng Liu
- National Center for Protein Science Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China;
| | - Ting Chen
- College of Biological and Medical Engineering, Donghua University, Shanghai 201620, China; (W.X.); (T.C.); (Y.Z.)
| | - Yunlong Zhang
- College of Biological and Medical Engineering, Donghua University, Shanghai 201620, China; (W.X.); (T.C.); (Y.Z.)
| | - Changrui Lu
- College of Biological and Medical Engineering, Donghua University, Shanghai 201620, China; (W.X.); (T.C.); (Y.Z.)
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16
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Saunier M, Fortier LC, Soutourina O. RNA-based regulation in bacteria-phage interactions. Anaerobe 2024; 87:102851. [PMID: 38583547 DOI: 10.1016/j.anaerobe.2024.102851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Interactions of bacteria with their viruses named bacteriophages or phages shape the bacterial genome evolution and contribute to the diversity of phages. RNAs have emerged as key components of several anti-phage defense systems in bacteria including CRISPR-Cas, toxin-antitoxin and abortive infection. Frequent association with mobile genetic elements and interplay between different anti-phage defense systems are largely discussed. Newly discovered defense systems such as retrons and CBASS include RNA components. RNAs also perform their well-recognized regulatory roles in crossroad of phage-bacteria regulatory networks. Both regulatory and defensive function can be sometimes attributed to the same RNA molecules including CRISPR RNAs. This review presents the recent advances on the role of RNAs in the bacteria-phage interactions with a particular focus on clostridial species including an important human pathogen, Clostridioides difficile.
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Affiliation(s)
- Marion Saunier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France; Institut Universitaire de France (IUF), Paris, France.
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17
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Ednacot EMQ, Nabhani A, Dinh DM, Morehouse BR. Pharmacological potential of cyclic nucleotide signaling in immunity. Pharmacol Ther 2024; 258:108653. [PMID: 38679204 DOI: 10.1016/j.pharmthera.2024.108653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 03/16/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
Cyclic nucleotides are important signaling molecules that play many critical physiological roles including controlling cell fate and development, regulation of metabolic processes, and responding to changes in the environment. Cyclic nucleotides are also pivotal regulators in immune signaling, orchestrating intricate processes that maintain homeostasis and defend against pathogenic threats. This review provides a comprehensive examination of the pharmacological potential of cyclic nucleotide signaling pathways within the realm of immunity. Beginning with an overview of the fundamental roles of cAMP and cGMP as ubiquitous second messengers, this review delves into the complexities of their involvement in immune responses. Special attention is given to the challenges associated with modulating these signaling pathways for therapeutic purposes, emphasizing the necessity for achieving cell-type specificity to avert unintended consequences. A major focus of the review is on the recent paradigm-shifting discoveries regarding specialized cyclic nucleotide signals in the innate immune system, notably the cGAS-STING pathway. The significance of cyclic dinucleotides, exemplified by 2'3'-cGAMP, in controlling immune responses against pathogens and cancer, is explored. The evolutionarily conserved nature of cyclic dinucleotides as antiviral agents, spanning across diverse organisms, underscores their potential as targets for innovative immunotherapies. Findings from the last several years have revealed a striking diversity of novel bacterial cyclic nucleotide second messengers which are involved in antiviral responses. Knowledge of the existence and precise identity of these molecules coupled with accurate descriptions of their associated immune defense pathways will be essential to the future development of novel antibacterial therapeutic strategies. The insights presented herein may help researchers navigate the evolving landscape of immunopharmacology as it pertains to cyclic nucleotides and point toward new avenues or lines of thinking about development of therapeutics against the pathways they regulate.
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Affiliation(s)
- Eirene Marie Q Ednacot
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Ali Nabhani
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - David M Dinh
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Benjamin R Morehouse
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA; Institute for Immunology, University of California Irvine, Irvine, CA 92697, USA; Center for Virus Research, University of California Irvine, Irvine, CA 92697, USA.
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18
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Singh RN, Sani RK. Genome-Wide Computational Prediction and Analysis of Noncoding RNAs in Oleidesulfovibrio alaskensis G20. Microorganisms 2024; 12:960. [PMID: 38792789 PMCID: PMC11124144 DOI: 10.3390/microorganisms12050960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Noncoding RNAs (ncRNAs) play key roles in the regulation of important pathways, including cellular growth, stress management, signaling, and biofilm formation. Sulfate-reducing bacteria (SRB) contribute to huge economic losses causing microbial-induced corrosion through biofilms on metal surfaces. To effectively combat the challenges posed by SRB, it is essential to understand their molecular mechanisms of biofilm formation. This study aimed to identify ncRNAs in the genome of a model SRB, Oleidesulfovibrio alaskensis G20 (OA G20). Three in silico approaches revealed genome-wide distribution of 37 ncRNAs excluding tRNAs in the OA G20. These ncRNAs belonged to 18 different Rfam families. This study identified riboswitches, sRNAs, RNP, and SRP. The analysis revealed that these ncRNAs could play key roles in the regulation of several pathways of biosynthesis and transport involved in biofilm formation by OA G20. Three sRNAs, Pseudomonas P10, Hammerhead type II, and sX4, which were found in OA G20, are rare and their roles have not been determined in SRB. These results suggest that applying various computational methods could enrich the results and lead to the discovery of additional novel ncRNAs, which could lead to understanding the "rules of life of OA G20" during biofilm formation.
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Affiliation(s)
- Ram Nageena Singh
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD 57701, USA;
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota Mines, Rapid City, SD 57701, USA
| | - Rajesh K. Sani
- Department of Chemical and Biological Engineering, South Dakota Mines, Rapid City, SD 57701, USA;
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota Mines, Rapid City, SD 57701, USA
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota Mines, Rapid City, SD 57701, USA
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19
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Akatsu Y, Mutsuro-Aoki H, Tamura K. Development of Allosteric Ribozymes for ATP and l-Histidine Based on the R3C Ligase Ribozyme. Life (Basel) 2024; 14:520. [PMID: 38672790 PMCID: PMC11051094 DOI: 10.3390/life14040520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
During the evolution of the RNA, short RNAs are thought to have joined together to form long RNAs, enhancing their function as ribozymes. Previously, the artificial R3C ligase ribozyme (73 nucleotides) was successfully reduced to 46 nucleotides; however, its activity decreased significantly. Therefore, we aimed to develop allosteric ribozymes, whose activities could be regulated by effector compounds, based on the reduced R3C ligase ribozyme (R3C-A). Among the variants prepared by fusing an ATP-binding aptamer RNA with R3C-A, one mutant showed increased ligation activity in an ATP-dependent manner. Melting temperature measurements of the two RNA mutants suggested that the region around the aptamer site was stabilized by the addition of ATP. This resulted in a suitable conformation for the reaction at the ligation site. Another ribozyme was prepared by fusing R3C-A with a l-histidine-binding aptamer RNA, and the ligase activity increased with increasing l-histidine concentrations. Both ATP and l-histidine play prominent roles in current molecular biology and the interaction of RNAs and these molecules could be a key step in the evolution of the world of RNAs. Our results suggest promise in the development of general allosteric ribozymes that are independent of the type of effector molecule and provide important clues to the evolution of the RNA world.
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Affiliation(s)
- Yuna Akatsu
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; (Y.A.); (H.M.-A.)
| | - Hiromi Mutsuro-Aoki
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; (Y.A.); (H.M.-A.)
| | - Koji Tamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; (Y.A.); (H.M.-A.)
- Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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20
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Warren Norris MAH, Plaskon DM, Tamayo R. Phase Variation of Flagella and Toxins in Clostridioides difficile is Mediated by Selective Rho-dependent Termination. J Mol Biol 2024; 436:168456. [PMID: 38278436 PMCID: PMC10942720 DOI: 10.1016/j.jmb.2024.168456] [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: 10/26/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
Clostridioides difficile is an intestinal pathogen that exhibits phase variation of flagella and toxins through inversion of the flagellar (flg) switch controlling flagellar and toxin gene expression. The transcription termination factor Rho preferentially inhibits swimming motility of bacteria with the 'flg-OFF' switch sequence. How C. difficile Rho mediates this selectivity was unknown. C. difficile Rho contains an N-terminal insertion domain (NID) which is found in a subset of Rho orthologues and confers diverse functions. Here we determined how Rho distinguishes between flg-ON and -OFF mRNAs and the roles of the NID and other domains of C. difficile Rho. Using in vitro ATPase assays, we determined that Rho specifically binds a region containing the left inverted repeat of the flg switch, but only of flg-OFF mRNA, indicating that differential termination is mediated by selective Rho binding. Using a suite of in vivo and in vitro assays in C. difficile, we determined that the NID is essential for Rho termination of flg-OFF mRNA, likely by influencing the ability to form stable hexamers, and the RNA binding domain is critical for flg-OFF specific termination. This work gives insight into the novel mechanism by which Rho interacts with flg mRNA to mediate phase variation of flagella and toxins in C. difficile and broadens our understanding of Rho-mediated termination in an organism with an AT-rich genome.
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Affiliation(s)
- Mercedes A H Warren Norris
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Dylan M Plaskon
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA.
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21
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Liu C, Shi R, Jensen MS, Zhu J, Liu J, Liu X, Sun D, Liu W. The global regulation of c-di-GMP and cAMP in bacteria. MLIFE 2024; 3:42-56. [PMID: 38827514 PMCID: PMC11139211 DOI: 10.1002/mlf2.12104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/16/2023] [Accepted: 10/09/2023] [Indexed: 06/04/2024]
Abstract
Nucleotide second messengers are highly versatile signaling molecules that regulate a variety of key biological processes in bacteria. The best-studied examples are cyclic AMP (cAMP) and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which both act as global regulators. Global regulatory frameworks of c-di-GMP and cAMP in bacteria show several parallels but also significant variances. In this review, we illustrate the global regulatory models of the two nucleotide second messengers, compare the different regulatory frameworks between c-di-GMP and cAMP, and discuss the mechanisms and physiological significance of cross-regulation between c-di-GMP and cAMP. c-di-GMP responds to numerous signals dependent on a great number of metabolic enzymes, and it regulates various signal transduction pathways through its huge number of effectors with varying activities. In contrast, due to the limited quantity, the cAMP metabolic enzymes and its major effector are regulated at different levels by diverse signals. cAMP performs its global regulatory function primarily by controlling the transcription of a large number of genes via cAMP receptor protein (CRP) in most bacteria. This review can help us understand how bacteria use the two typical nucleotide second messengers to effectively coordinate and integrate various physiological processes, providing theoretical guidelines for future research.
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Affiliation(s)
- Cong Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Rui Shi
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Marcus S. Jensen
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Jingrong Zhu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Jiawen Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Xiaobo Liu
- Key Laboratory of Metabolic Engineering and Biosynthesis Technology, Ministry of Industry and Information TechnologyNanjing University of Science and TechnologyNanjingChina
| | - Di Sun
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Weijie Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
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22
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Barth KM, Hiller DA, Strobel SA. The Impact of Second-Shell Nucleotides on Ligand Specificity in Cyclic Dinucleotide Riboswitches. Biochemistry 2024:10.1021/acs.biochem.3c00586. [PMID: 38329042 PMCID: PMC11306416 DOI: 10.1021/acs.biochem.3c00586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Ligand specificity is an essential requirement for all riboswitches. Some variant riboswitches utilize a common structural motif, yet through subtle sequence differences, they are able to selectively respond to different small molecule ligands and regulate downstream gene expression. These variants discriminate between structurally and chemically similar ligands. Crystal structures provide insight into how specificity is achieved. However, ligand specificity cannot always be explained solely by nucleotides in direct contact with the ligand. The cyclic dinucleotide variant family contains two classes, cyclic-di-GMP and cyclic-AMP-GMP riboswitches, that were distinguished based on the identity of a single nucleotide in contact with the ligand. Here we report a variant riboswitch with a mutation at a second ligand-contacting position that is promiscuous for both cyclic-di-GMP and cyclic-AMP-GMP despite a predicted preference for cyclic-AMP-GMP. A high-throughput mutational analysis, SMARTT, was used to quantitatively assess thousands of sites in the first- and second-shells of ligand contact for impacts on ligand specificity and promiscuity. In addition to nucleotides in direct ligand contact, nucleotides more distal from the binding site, within the J1/2 linker and the terminator helix, were identified that impact ligand specificity. These findings provide an example of how nucleotides outside the ligand binding pocket influence the riboswitch specificity. Moreover, these distal nucleotides could be used to predict promiscuous sequences.
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Affiliation(s)
- Kathryn M. Barth
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT 06516, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - David A. Hiller
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT 06516, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Scott A. Strobel
- Institute of Biomolecular Design and Discovery, Yale University, West Haven, CT 06516, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
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23
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Vuotto C, Donelli G, Buckley A, Chilton C. Clostridioides difficile Biofilm. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1435:249-272. [PMID: 38175479 DOI: 10.1007/978-3-031-42108-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Clostridioides difficile infection (CDI), previously Clostridium difficile infection, is a symptomatic infection of the large intestine caused by the spore-forming anaerobic, gram-positive bacterium Clostridioides difficile. CDI is an important healthcare-associated disease worldwide, characterized by high levels of recurrence, morbidity, and mortality. CDI is observed at a higher rate in immunocompromised patients after antimicrobial therapy, with antibiotics disrupting the commensal microbiota and promoting C. difficile colonization of the gastrointestinal tract.A rise in clinical isolates resistant to multiple antibiotics and the reduced susceptibility to the most commonly used antibiotic molecules have made the treatment of CDI more complicated, allowing the persistence of C. difficile in the intestinal environment.Gut colonization and biofilm formation have been suggested to contribute to the pathogenesis and persistence of C. difficile. In fact, biofilm growth is considered as a serious threat because of the related antimicrobial tolerance that makes antibiotic therapy often ineffective. This is the reason why the involvement of C. difficile biofilm in the pathogenesis and recurrence of CDI is attracting more and more interest, and the mechanisms underlying biofilm formation of C. difficile as well as the role of biofilm in CDI are increasingly being studied by researchers in the field.Findings on C. difficile biofilm, possible implications in CDI pathogenesis and treatment, efficacy of currently available antibiotics in treating biofilm-forming C. difficile strains, and some antimicrobial alternatives under investigation will be discussed here.
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Affiliation(s)
- Claudia Vuotto
- Microbial Biofilm Laboratory, IRCCS Fondazione Santa Lucia, Rome, Italy.
| | | | - Anthony Buckley
- Microbiome and Nutritional Sciences Group, School of Food Science & Nutrition, University of Leeds, Leeds, UK
| | - Caroline Chilton
- Healthcare Associated Infection Research Group, Section of Molecular Gastroenterology, Leeds Institute for Medical Research at St James, University of Leeds, Leeds, UK
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Hamal Dhakal S, Kavita K, Panchapakesan SSS, Roth A, Breaker RR. 8-oxoguanine riboswitches in bacteria detect and respond to oxidative DNA damage. Proc Natl Acad Sci U S A 2023; 120:e2307854120. [PMID: 37748066 PMCID: PMC10556655 DOI: 10.1073/pnas.2307854120] [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: 05/10/2023] [Accepted: 08/25/2023] [Indexed: 09/27/2023] Open
Abstract
Riboswitches rely on structured aptamer domains to selectively sense their target ligands and regulate gene expression. However, some riboswitch aptamers in bacteria carry mutations in their otherwise strictly conserved binding pockets that change ligand specificities. The aptamer domain of a riboswitch class originally found to selectively sense guanine forms a three-stem junction that has since been observed to exploit numerous alterations in its ligand-binding pocket. These rare variants have modified their ligand specificities to sense other purines or purine derivatives, including adenine, 2'-deoxyguanosine (three classes), and xanthine. Herein, we report the characteristics of a rare variant that is narrowly distributed in the Paenibacillaceae family of bacteria. Known representatives are always associated with genes encoding 8-oxoguanine deaminase. As predicted from this gene association, these variant riboswitches tightly bind 8-oxoguanine (8-oxoG), strongly discriminate against other purine derivatives, and function as genetic "ON" switches. Following exposure of cells to certain oxidative stresses, a representative 8-oxoG riboswitch activates gene expression, likely caused by the accumulation of 8-oxoG due to oxidative damage to G nucleobases in DNA, RNA, and the nucleotide pool. Furthermore, an engineered version of the variant aptamer was prepared that exhibits specificity for 8-oxoadenine, further demonstrating that RNA aptamers can acquire mutations that expand their ability to detect and respond to oxidative damage.
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Affiliation(s)
- Siddhartha Hamal Dhakal
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
| | - Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
| | | | - Adam Roth
- HHMI, Yale University, New Haven, CT06511-8103
| | - Ronald R. Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511-8103
- HHMI, Yale University, New Haven, CT06511-8103
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT06511-8103
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Khan F, Jeong GJ, Tabassum N, Kim YM. Functional diversity of c-di-GMP receptors in prokaryotic and eukaryotic systems. Cell Commun Signal 2023; 21:259. [PMID: 37749602 PMCID: PMC10519070 DOI: 10.1186/s12964-023-01263-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/09/2023] [Indexed: 09/27/2023] Open
Abstract
Cyclic bis-(3', 5')-dimeric guanosine monophosphate (c-di-GMP) is ubiquitous in many bacterial species, where it functions as a nucleotide-based secondary messenger and is a vital regulator of numerous biological processes. Due to its ubiquity, most bacterial species possess a wide range of downstream receptors that has a binding affinity to c-di-GMP and elicit output responses. In eukaryotes, several enzymes and riboswitches operate as receptors that interact with c-di-GMP and transduce cellular or environmental signals. This review examines the functional variety of receptors in prokaryotic and eukaryotic systems that exhibit distinct biological responses after interacting with c-di-GMP. Evolutionary relationships and similarities in distance among the c-di-GMP receptors in various bacterial species were evaluated to understand their specificities. Furthermore, residues of receptors involved in c-di-GMP binding are summarized. This review facilitates the understanding of how distinct receptors from different origins bind c-di-GMP equally well, yet fulfill diverse biological roles at the interspecies, intraspecies, and interkingdom levels. Furthermore, it also highlights c-di-GMP receptors as potential therapeutic targets, particularly those found in pathogenic microorganisms. Video Abstract.
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Affiliation(s)
- Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Young-Mog Kim
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
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Xu J, Hou J, Ding M, Wang Z, Chen T. Riboswitches, from cognition to transformation. Synth Syst Biotechnol 2023; 8:357-370. [PMID: 37325181 PMCID: PMC10265488 DOI: 10.1016/j.synbio.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/20/2023] [Accepted: 05/25/2023] [Indexed: 06/17/2023] Open
Abstract
Riboswitches are functional RNA elements that regulate gene expression by directly detecting metabolites. Twenty years have passed since it was first discovered, researches on riboswitches are becoming increasingly standardized and refined, which could significantly promote people's cognition of RNA function as well. Here, we focus on some representative orphan riboswitches, enumerate the structural and functional transformation and artificial design of riboswitches including the coupling with ribozymes, hoping to attain a comprehensive understanding of riboswitch research.
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Affiliation(s)
- Jingdong Xu
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
- Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, 300350, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300350, China
| | - Junyuan Hou
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
- Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, 300350, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300350, China
| | - Mengnan Ding
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
- Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, 300350, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300350, China
| | - Zhiwen Wang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
- Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, 300350, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300350, China
| | - Tao Chen
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
- Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, 300350, China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300350, China
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27
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Fekete FJ, Marotta NJ, Liu X, Weinert EE. An O 2-sensing diguanylate cyclase broadly affects the aerobic transcriptome in the phytopathogen Pectobacterium carotovorum. Front Microbiol 2023; 14:1134742. [PMID: 37485529 PMCID: PMC10360401 DOI: 10.3389/fmicb.2023.1134742] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 06/26/2023] [Indexed: 07/25/2023] Open
Abstract
Pectobacterium carotovorum is an important plant pathogen responsible for the destruction of crops through bacterial soft rot, which is modulated by oxygen (O2) concentration. A soluble globin coupled sensor protein, Pcc DgcO (also referred to as PccGCS) is one way through which P. carotovorum senses oxygen. DgcO contains a diguanylate cyclase output domain producing c-di-GMP. Synthesis of the bacterial second messenger c-di-GMP is increased upon oxygen binding to the sensory globin domain. This work seeks to understand regulation of function by DgcO at the transcript level. RNA sequencing and differential expression analysis revealed that the deletion of DgcO only affects transcript levels in cells grown under aerobic conditions. Differential expression analysis showed that DgcO deletion alters transcript levels for metal transporters. These results, followed by inductively coupled plasma-mass spectrometry showing decreased concentrations of six biologically relevant metals upon DgcO deletion, provide evidence that a globin coupled sensor can affect cellular metal content. These findings improve the understanding of the transcript level control of O2-dependent phenotypes in an important phytopathogen and establish a basis for further studies on c-di-GMP-dependent functions in P. carotovorum.
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Affiliation(s)
- Florian J. Fekete
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, United States
| | - Nick J. Marotta
- Graduate Program in Molecular, Cellular, and Integrative Biosciences, Penn State University, University Park, PA, United States
| | - Xuanyu Liu
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, United States
| | - Emily E. Weinert
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, United States
- Department of Chemistry, Penn State University, University Park, PA, United States
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28
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Ni P, Zhao Y, Zhou X, Liu Z, Huang Z, Ni Z, Sun Q, Zong Y. Efficient and versatile multiplex prime editing in hexaploid wheat. Genome Biol 2023; 24:156. [PMID: 37386475 PMCID: PMC10308706 DOI: 10.1186/s13059-023-02990-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 06/15/2023] [Indexed: 07/01/2023] Open
Abstract
Prime editing is limited by low efficiency in plants. Here, we develop an upgraded engineered plant prime editor in hexaploid wheat, ePPEplus, by introducing a V223A substitution into reverse transcriptase in the ePPEmax* architecture. ePPEplus enhances the efficiency by an average 33.0-fold and 6.4-fold compared to the original PPE and ePPE, respectively. Importantly, a robust multiplex prime editing platform is established for simultaneous editing of four to ten genes in protoplasts and up to eight genes in regenerated wheat plants at frequencies up to 74.5%, thus expanding the applicability of prime editors for stacking of multiple agronomic traits.
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Affiliation(s)
- Pei Ni
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yidi Zhao
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Ximeng Zhou
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zehua Liu
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhengwei Huang
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhongfu Ni
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yuan Zong
- Frontiers Science Center for Molecular Design Breeding (MOE), Key Laboratory of Crop Heterosis and Utilization (MOE), and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
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29
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Römling U, Cao LY, Bai FW. Evolution of cyclic di-GMP signalling on a short and long term time scale. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001354. [PMID: 37384391 PMCID: PMC10333796 DOI: 10.1099/mic.0.001354] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023]
Abstract
Diversifying radiation of domain families within specific lineages of life indicates the importance of their functionality for the organisms. The foundation for the diversifying radiation of the cyclic di-GMP signalling network that occurred within the bacterial kingdom is most likely based in the outmost adaptability, flexibility and plasticity of the system. Integrative sensing of multiple diverse extra- and intracellular signals is made possible by the N-terminal sensory domains of the modular cyclic di-GMP turnover proteins, mutations in the protein scaffolds and subsequent signal reception by diverse receptors, which eventually rewires opposite host-associated as well as environmental life styles including parallel regulated target outputs. Natural, laboratory and microcosm derived microbial variants often with an altered multicellular biofilm behaviour as reading output demonstrated single amino acid substitutions to substantially alter catalytic activity including substrate specificity. Truncations and domain swapping of cyclic di-GMP signalling genes and horizontal gene transfer suggest rewiring of the network. Presence of cyclic di-GMP signalling genes on horizontally transferable elements in particular observed in extreme acidophilic bacteria indicates that cyclic di-GMP signalling and biofilm components are under selective pressure in these types of environments. On a short and long term evolutionary scale, within a species and in families within bacterial orders, respectively, the cyclic di-GMP signalling network can also rapidly disappear. To investigate variability of the cyclic di-GMP signalling system on various levels will give clues about evolutionary forces and discover novel physiological and metabolic pathways affected by this intriguing second messenger signalling system.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
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Junkermeier EH, Hengge R. Local signaling enhances output specificity of bacterial c-di-GMP signaling networks. MICROLIFE 2023; 4:uqad026. [PMID: 37251514 PMCID: PMC10211494 DOI: 10.1093/femsml/uqad026] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/31/2023]
Abstract
For many years the surprising multiplicity, signal input diversity, and output specificity of c-di-GMP signaling proteins has intrigued researchers studying bacterial second messengers. How can several signaling pathways act in parallel to produce specific outputs despite relying on the same diffusible second messenger maintained at a certain global cellular concentration? Such high specificity and flexibility arise from combining modes of local and global c-di-GMP signaling in complex signaling networks. Local c-di-GMP signaling can be experimentally shown by three criteria being met: (i) highly specific knockout phenotypes for particular c-di-GMP-related enzymes, (ii) actual cellular c-di-GMP levels that remain unchanged by such mutations and/or below the Kd's of the relevant c-di-GMP-binding effectors, and (iii) direct interactions between the signaling proteins involved. Here, we discuss the rationale behind these criteria and present well-studied examples of local c-di-GMP signaling in Escherichia coli and Pseudomonas. Relatively simple systems just colocalize a local source and/or a local sink for c-di-GMP, i.e. a diguanylate cyclase (DGC) and/or a specific phosphodiesterase (PDE), respectively, with a c-di-GMP-binding effector/target system. More complex systems also make use of regulatory protein interactions, e.g. when a "trigger PDE" responds to locally provided c-di-GMP, and thereby serves as a c-di-GMP-sensing effector that directly controls a target's activity, or when a c-di-GMP-binding effector recruits and directly activates its own "private" DGC. Finally, we provide an outlook into how cells can combine local and global signaling modes of c-di-GMP and possibly integrate those into other signaling nucleotides networks.
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Affiliation(s)
- Eike H Junkermeier
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Philippstr. 13 – Haus 22, 10115 Berlin, Germany
| | - Regine Hengge
- Corresponding author. Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Philippstr. 13 – Haus 22, 10115 Berlin, Germany. Tel: +49-30-2093-49686; Fax: +49-30-2093-49682; E-mail:
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31
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Chandra H, Sorg JA, Hassett DJ, Sun X. Regulatory transcription factors of Clostridioides difficile pathogenesis with a focus on toxin regulation. Crit Rev Microbiol 2023; 49:334-349. [PMID: 35389761 PMCID: PMC11209739 DOI: 10.1080/1040841x.2022.2054307] [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: 05/11/2021] [Revised: 02/26/2022] [Accepted: 03/14/2022] [Indexed: 11/03/2022]
Abstract
Clostridioides difficile (CD), a nosocomial gut pathogen, produces two major exotoxins, TcdA and TcdB, which disrupt the gut epithelial barrier and induce inflammatory/immune responses, leading to symptoms ranging from mild diarrhoea to pseudomembranous colitis and potentially to death. The expression of toxins is regulated by various transcription factors (TFs) which are induced in response to CD physiological life stages, nutritional availability, and host environment. This review summarises our current understanding on the regulation of toxin expression by TFs that interconnect with pathways of flagellar synthesis, quorum sensing, motility, biofilm formation, sporulation, and phase variation. The pleiotropic roles of some key TFs suggest that toxin production is tightly linked to other cellular processes of the CD physiology.
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Affiliation(s)
- Harish Chandra
- Department of Environmental Microbiology, School of Environmental and Earth Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Daniel J Hassett
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Xingmin Sun
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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Hengge R, Pruteanu M, Stülke J, Tschowri N, Turgay K. Recent advances and perspectives in nucleotide second messenger signaling in bacteria. MICROLIFE 2023; 4:uqad015. [PMID: 37223732 PMCID: PMC10118264 DOI: 10.1093/femsml/uqad015] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/28/2023] [Accepted: 04/13/2023] [Indexed: 05/25/2023]
Abstract
Nucleotide second messengers act as intracellular 'secondary' signals that represent environmental or cellular cues, i.e. the 'primary' signals. As such, they are linking sensory input with regulatory output in all living cells. The amazing physiological versatility, the mechanistic diversity of second messenger synthesis, degradation, and action as well as the high level of integration of second messenger pathways and networks in prokaryotes has only recently become apparent. In these networks, specific second messengers play conserved general roles. Thus, (p)ppGpp coordinates growth and survival in response to nutrient availability and various stresses, while c-di-GMP is the nucleotide signaling molecule to orchestrate bacterial adhesion and multicellularity. c-di-AMP links osmotic balance and metabolism and that it does so even in Archaea may suggest a very early evolutionary origin of second messenger signaling. Many of the enzymes that make or break second messengers show complex sensory domain architectures, which allow multisignal integration. The multiplicity of c-di-GMP-related enzymes in many species has led to the discovery that bacterial cells are even able to use the same freely diffusible second messenger in local signaling pathways that can act in parallel without cross-talking. On the other hand, signaling pathways operating with different nucleotides can intersect in elaborate signaling networks. Apart from the small number of common signaling nucleotides that bacteria use for controlling their cellular "business," diverse nucleotides were recently found to play very specific roles in phage defense. Furthermore, these systems represent the phylogenetic ancestors of cyclic nucleotide-activated immune signaling in eukaryotes.
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Affiliation(s)
- Regine Hengge
- Corresponding author. Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Philippstr. 13 – Haus 22, 10115 Berlin, Germany. Tel: +49-30-2093-49686; Fax: +49-30-2093-49682; E-mail:
| | | | - Jörg Stülke
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Natalia Tschowri
- Institute of Microbiology, Leibniz-Universität Hannover, 30419 Hannover, Germany
| | - Kürşad Turgay
- Institute of Microbiology, Leibniz-Universität Hannover, 30419 Hannover, Germany
- Max Planck Unit for the Science of Pathogens, 10115 Berlin, Germany
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Kavita K, Breaker RR. Discovering riboswitches: the past and the future. Trends Biochem Sci 2023; 48:119-141. [PMID: 36150954 PMCID: PMC10043782 DOI: 10.1016/j.tibs.2022.08.009] [Citation(s) in RCA: 121] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 01/25/2023]
Abstract
Riboswitches are structured noncoding RNA domains used by many bacteria to monitor the concentrations of target ligands and regulate gene expression accordingly. In the past 20 years over 55 distinct classes of natural riboswitches have been discovered that selectively sense small molecules or elemental ions, and thousands more are predicted to exist. Evidence suggests that some riboswitches might be direct descendants of the RNA-based sensors and switches that were likely present in ancient organisms before the evolutionary emergence of proteins. We provide an overview of the current state of riboswitch research, focusing primarily on the discovery of riboswitches, and speculate on the major challenges facing researchers in the field.
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Affiliation(s)
- Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA.
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34
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Serrano-Gutiérrez M, Merino E. Antisense-acting riboswitches: A poorly characterized yet important model of transcriptional regulation in prokaryotic organisms. PLoS One 2023; 18:e0281744. [PMID: 36809273 PMCID: PMC9943018 DOI: 10.1371/journal.pone.0281744] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/30/2023] [Indexed: 02/23/2023] Open
Abstract
Riboswitches are RNA elements involved in regulating genes that participate in the biosynthesis or transport of essential metabolites. They are characterized by their ability to recognize their target molecules with high affinity and specificity. Riboswitches are commonly cotranscribed with their target genes and are located at the 5' end of their transcriptional units. To date, only two exceptional cases of riboswitches being situated at the 3' end and transcribing in the antisense direction of their regulated genes have been described. The first case involves a SAM riboswitch located at the 3' end of the ubiG-mccB-mccA operon in Clostridium acetobutylicum involved in converting methionine to cysteine. The second case concerns a Cobalamin riboswitch in Listeria monocytogenes that regulates the transcription factor PocR related to this organism's pathogenic process. In almost a decade since the first descriptions of antisense-acting riboswitches, no new examples have been described. In this work, we performed a computational analysis to identify new examples of antisense-acting riboswitches. We found 292 cases in which, according to the available information, we infer that the expected regulation of the riboswitch is consistent with the signaling molecule it senses and the metabolic function of the regulated gene. The metabolic implications of this novel type of regulation are thoroughly discussed.
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Affiliation(s)
- Mariela Serrano-Gutiérrez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail:
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35
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Yuan C, Sun F, Zhang J, Feng L, Tu H, Li A. Low-temperature-resistance granulation of activated sludge and the microbial responses to the granular structural stabilization. CHEMOSPHERE 2023; 311:137146. [PMID: 36347348 DOI: 10.1016/j.chemosphere.2022.137146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/14/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Completely loss of granular structural stability and reliable start-up of aerobic granular sludge (AGS) system are considered as the biggest challenges for its engineering application under seasonal temperature variation, especially extremely low temperatures. In this study, two identical sequencing batch reactors (SBR) were successfully start-up at 10 °C (R1) and 25 °C (R2), respectively, and then operated under a strategy of stepwise change of temperatures to investigate the stability of the granular sludge by examining its microbial characteristics, bis (3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), extracellular polymeric substance (EPS) and sludge physiochemical properties. The results showed that AGS formed under the low temperature preferentially secrete EPS and c-di-GMP for stable granulation and improvement of its resistance to temperature changes. Meanwhile, R1 successfully obtained aerobic granulation with high biomass concentration and superior settleability, as well as high pollutant removal performance. In comparison, R2 took a longer time for granulation and was subjected to serious disintegration of AGS. The matrix structure partially formed by filamentous bacteria during the start-up stage in R1 was one of major reasons for its own superiority beyond R2 in granulation. Slow-growing organisms such as autotrophic nitrifying and Anammox bacteria, phosphorus accumulation organisms, EPS-producing genera, and c-di-GMP pathway-dependent genera, were exclusively enriched in the R1 and resulted in higher pollutants removal efficiencies and stable structure, whereas Sphaerotilus dominated in R2 that related closely with its unstable performance. Therefore, the strategy based on the stepwise change of temperatures from extremely low temperatures may be one feasible way for the sustainable application of AGS system, which is of significance to address the challenging problems of AGS applications.
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Affiliation(s)
- Chunyan Yuan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China; Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen, 518055, People's Republic of China
| | - Feiyun Sun
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China; Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen, 518055, People's Republic of China.
| | - Jianjun Zhang
- Shenzhen Municipal Design & Research Institute Co. Ltd., People's Republic of China
| | - Liang Feng
- Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen, 518055, People's Republic of China
| | - Honghua Tu
- Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen, 518055, People's Republic of China
| | - Ang Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China.
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Autoinducer-2 and bile salts induce c-di-GMP synthesis to repress the T3SS via a T3SS chaperone. Nat Commun 2022; 13:6684. [PMID: 36335118 PMCID: PMC9637222 DOI: 10.1038/s41467-022-34607-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 10/31/2022] [Indexed: 11/07/2022] Open
Abstract
Cyclic di-GMP (c-di-GMP) transduces extracellular stimuli into intracellular responses, coordinating a plethora of important biological processes. Low levels of c-di-GMP are often associated with highly virulent behavior that depends on the type III secretion system (T3SS) effectors encoded, whereas elevated levels of c-di-GMP lead to the repression of T3SSs. However, extracellular signals that modulate c-di-GMP metabolism to control T3SSs and c-di-GMP effectors that relay environmental stimuli to changes in T3SS activity remain largely obscure. Here, we show that the quorum sensing signal autoinducer-2 (AI-2) induces c-di-GMP synthesis via a GAPES1 domain-containing diguanylate cyclase (DGC) YeaJ to repress T3SS-1 gene expression in Salmonella enterica serovar Typhimurium. YeaJ homologs capable of sensing AI-2 are present in many other species belonging to Enterobacterales. We also reveal that taurocholate and taurodeoxycholate bind to the sensory domain of the DGC YedQ to induce intracellular accumulation of c-di-GMP, thus repressing the expression of T3SS-1 genes. Further, we find that c-di-GMP negatively controls the function of T3SSs through binding to the widely conserved CesD/SycD/LcrH family of T3SS chaperones. Our results support a model in which bacteria sense changes in population density and host-derived cues to regulate c-di-GMP synthesis, thereby modulating the activity of T3SSs via a c-di-GMP-responsive T3SS chaperone.
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Elongation factor P modulates Acinetobacter baumannii physiology and virulence as a cyclic dimeric guanosine monophosphate effector. Proc Natl Acad Sci U S A 2022; 119:e2209838119. [PMID: 36191190 PMCID: PMC9564936 DOI: 10.1073/pnas.2209838119] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclic diguanosine monophosphate (c-di-GMP) is widely used by bacteria to control biological functions in response to diverse signals or cues. A previous study showed that potential c-di-GMP metabolic enzymes play a role in the regulation of biofilm formation and motility in Acinetobacter baumannii. However, it was unclear whether and how A. baumannii cells use c-di-GMP signaling to modulate biological functions. Here, we report that c-di-GMP is an important intracellular signal in the modulation of biofilm formation, motility, and virulence in A. baumannii. The intracellular level of c-di-GMP is principally controlled by the diguanylate cyclases (DGCs) A1S_1695, A1S_2506, and A1S_3296 and the phosphodiesterase (PDE) A1S_1254. Intriguingly, we revealed that A1S_2419 (an elongation factor P [EF-P]), is a novel c-di-GMP effector in A. baumannii. Response to a c-di-GMP signal boosted A1S_2419 activity to rescue ribosomes from stalling during synthesis of proteins containing consecutive prolines and thus regulate A. baumannii physiology and pathogenesis. Our study presents a unique and widely conserved effector that controls bacterial physiology and virulence by sensing the second messenger c-di-GMP.
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38
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Vikram, Mishra V, Rana A, Ahire JJ. Riboswitch-mediated regulation of riboflavin biosynthesis genes in prokaryotes. 3 Biotech 2022; 12:278. [PMID: 36275359 PMCID: PMC9474784 DOI: 10.1007/s13205-022-03348-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 09/02/2022] [Indexed: 11/01/2022] Open
Abstract
Prokaryotic organisms frequently use riboswitches to quantify intracellular metabolite concentration via high-affinity metabolite receptors. Riboswitches possess a metabolite-sensing system that controls gene regulation in a cis-acting fashion at the initiation of transcriptional/translational level by binding with a specific metabolite and controlling various biochemical pathways. Riboswitch binds with flavin mononucleotide (FMN), a phosphorylated form of riboflavin and controls gene expression involved in riboflavin biosynthesis and transport pathway. The first step of the riboflavin biosynthesis pathway is initiated by the conversion of guanine nucleotide triphosphate (GTP), which is an intermediate of the purine biosynthesis pathway. An alternative pentose phosphate pathway of riboflavin biosynthesis includes the enzymatic conversion of ribulose-5-phosphate into 3, 4 dihydroxy-2-butanone-4-phosphates by DHBP synthase. The product of ribAB interferes with both GTP cyclohydrolase II as well as DHBP synthase activities, which catalyze the cleavage of GTP and converts DHBP Ribu5P in the initial steps of both riboflavin biosynthesis branches. Riboswitches are located in the 5' untranslated region (5' UTR) of messenger RNAs and contain an aptamer domain (highly conserved in sequence) where metabolite binding leads to a conformational change in an aptamer domain, which modulate the regulation of gene expression located on bacterial mRNA. In this review, we focus on how riboswitch regulates the riboflavin biosynthesis pathway in Bacillus subtilis and Lactobacillus plantarum.
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Affiliation(s)
- Vikram
- Department of Basic and Applied Sciences, National Institute of Food Technology, Entrepreneurship and Management (NIFTEM), Sonipat, Haryana India
| | - Vijendra Mishra
- Department of Basic and Applied Sciences, National Institute of Food Technology, Entrepreneurship and Management (NIFTEM), Sonipat, Haryana India
| | - Ananya Rana
- Department of Basic and Applied Sciences, National Institute of Food Technology, Entrepreneurship and Management (NIFTEM), Sonipat, Haryana India
| | - Jayesh J. Ahire
- Centre for Research and Development, Unique Biotech Ltd., Plot No. 2, Phase II, MN Park, Hyderabad, Telangana India
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Giarimoglou N, Kouvela A, Maniatis A, Papakyriakou A, Zhang J, Stamatopoulou V, Stathopoulos C. A Riboswitch-Driven Era of New Antibacterials. Antibiotics (Basel) 2022; 11:antibiotics11091243. [PMID: 36140022 PMCID: PMC9495366 DOI: 10.3390/antibiotics11091243] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/01/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022] Open
Abstract
Riboswitches are structured non-coding RNAs found in the 5′ UTR of important genes for bacterial metabolism, virulence and survival. Upon the binding of specific ligands that can vary from simple ions to complex molecules such as nucleotides and tRNAs, riboswitches change their local and global mRNA conformations to affect downstream transcription or translation. Due to their dynamic nature and central regulatory role in bacterial metabolism, riboswitches have been exploited as novel RNA-based targets for the development of new generation antibacterials that can overcome drug-resistance problems. During recent years, several important riboswitch structures from many bacterial representatives, including several prominent human pathogens, have shown that riboswitches are ideal RNA targets for new compounds that can interfere with their structure and function, exhibiting much reduced resistance over time. Most interestingly, mainstream antibiotics that target the ribosome have been shown to effectively modulate the regulatory behavior and capacity of several riboswitches, both in vivo and in vitro, emphasizing the need for more in-depth studies and biological evaluation of new antibiotics. Herein, we summarize the currently known compounds that target several main riboswitches and discuss the role of mainstream antibiotics as modulators of T-box riboswitches, in the dawn of an era of novel inhibitors that target important bacterial regulatory RNAs.
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Affiliation(s)
- Nikoleta Giarimoglou
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Adamantia Kouvela
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Alexandros Maniatis
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
| | - Athanasios Papakyriakou
- Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Ag. Paraskevi, 15341 Athens, Greece
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | | | - Constantinos Stathopoulos
- Department of Biochemistry, School of Medicine, University of Patras, 26504 Patras, Greece
- Correspondence: ; Tel.: +30-2610-997932
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40
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Pavlova N, Penchovsky R. Bioinformatics and Genomic Analyses of the Suitability of Eight Riboswitches for Antibacterial Drug Targets. Antibiotics (Basel) 2022; 11:antibiotics11091177. [PMID: 36139956 PMCID: PMC9495176 DOI: 10.3390/antibiotics11091177] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance (AR) is an acute problem that results in prolonged and debilitating illnesses. AR mortality worldwide is growing and causes a pressing need to research novel mechanisms of action and untested target molecules. This article presents in silico analyses of eight bacterial riboswitches for their suitability for antibacterial drug targets. Most bacterial riboswitches are located in the 5′-untranslated region of messenger RNAs, act as allosteric cis-acting gene control elements, and have not been found in humans before. Sensing metabolites, the riboswitches regulate the synthesis of vital cellular metabolites in various pathogenic bacteria. The analyses performed in this article represent a complete and informative genome-wide bioinformatics analysis of the adequacy of eight riboswitches as antibacterial drug targets in different pathogenic bacteria based on four criteria. Due to the ability of the riboswitch to control biosynthetic pathways and transport proteins of essential metabolites and the presence/absence of alternative biosynthetic pathways, we classified them into four groups based on their suitability for use as antibacterial drug targets guided by our in silico analyses. We concluded that some of them are promising targets for antibacterial drug discovery, such as the PreQ1, MoCo RNA, cyclic-di-GMP I, and cyclic-di-GMP II riboswitches.
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41
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Jiang D, Zeng Q, Banerjee B, Lin H, Srok J, Yu M, Yang C. The phytopathogen Dickeya dadantii 3937 cpxR locus gene participates in the regulation of virulence and the global c-di-GMP network. MOLECULAR PLANT PATHOLOGY 2022; 23:1187-1199. [PMID: 35460168 PMCID: PMC9276944 DOI: 10.1111/mpp.13219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/25/2022] [Accepted: 03/19/2022] [Indexed: 05/20/2023]
Abstract
Bacteria use signal transduction systems to sense and respond to their external environment. The two-component system CpxA/CpxR senses misfolded envelope protein stress and responds by up-regulating envelope protein factors and down-regulating virulence factors in several animal pathogens. Dickeya dadantii is a phytopathogen equipped with a type III secretion system (T3SS) for manipulating the host immune response. We found that deletion of cpxR enhanced the expression of the T3SS marker gene hrpA in a designated T3SS-inducing minimal medium (MM). In the ∆cpxR mutant, multiple T3SS and c-di-GMP regulators were also up-regulated. Subsequent analysis revealed that deletion of the phosphodiesterase gene egcpB in ∆cpxR abolished the enhanced T3SS expression. This suggested that CpxR suppresses EGcpB levels, causing low T3SS expression in MM. Furthermore, we found that the ∆cpxR mutant displayed low c-di-GMP phenotypes in biofilm formation and swimming. Increased production of cellular c-di-GMP by in trans expression of the diguanylate cyclase gene gcpA was negated in the ∆cpxR mutant. Here, we propose that CpxA/CpxR regulates T3SS expression by manipulating the c-di-GMP network, in turn modifying the multiple physiological activities involved in the response to environmental stresses in D. dadantii.
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Affiliation(s)
- Daqing Jiang
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWisconsinUSA
| | - Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew HavenConnecticutUSA
| | - Biswarup Banerjee
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWisconsinUSA
| | - Haiping Lin
- School of Forestry and BiotechnologyZhejiang Agricultural and Forestry UniversityHangzhouChina
| | - John Srok
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWisconsinUSA
| | - Manda Yu
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWisconsinUSA
| | - Ching‐Hong Yang
- Department of Biological SciencesUniversity of Wisconsin‐MilwaukeeMilwaukeeWisconsinUSA
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Shrestha P, Razvi A, Fung BL, Eichinger SJ, Visick KL. Mutational Analysis of Vibrio fischeri c-di-GMP-Modulating Genes Reveals Complex Regulation of Motility. J Bacteriol 2022; 204:e0010922. [PMID: 35758751 PMCID: PMC9295575 DOI: 10.1128/jb.00109-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/04/2022] [Indexed: 12/30/2022] Open
Abstract
The symbiont Vibrio fischeri uses motility to colonize its host. In numerous bacterial species, motility is negatively controlled by cyclic-di-GMP (c-di-GMP), which is produced by diguanylate cyclases (DGCs) with GGDEF domains and degraded by phosphodiesterases with either EAL or HD-GYP domains. To begin to decode the functions of the 50 Vibrio fischeri genes with GGDEF, EAL, and/or HD-GYP domains, we deleted each gene and assessed each mutant's migration through tryptone broth salt (TBS) soft agar medium containing or lacking magnesium (Mg) and calcium (Ca), which are known to influence V. fischeri motility. We identified 6, 13, and 16 mutants with altered migration in TBS-Mg, TBS, and TBS-Ca soft agar, respectively, a result that underscores the importance of medium conditions in assessing gene function. A biosensor-based assay revealed that Mg and Ca affected c-di-GMP levels negatively and positively, respectively; the severe decrease in c-di-GMP caused by Mg addition correlates with its strong positive impact on bacterial migration. A mutant defective for VF_0494, a homolog of V. cholerae rocS, exhibited a severe defect in migration across all conditions. Motility of a VF_1603 VF_2480 double mutant was also severely defective and could be restored by expression of "c-di-GMP-blind" alleles of master flagellar regulator flrA. Together, this work sheds light on the genes and conditions that influence c-di-GMP-mediated control over motility in V. fischeri and provides a foundation for (i) assessing roles of putative c-di-GMP-binding proteins, (ii) evaluating other c-di-GMP-dependent phenotypes in V. fischeri, (iii) uncovering potential redundancy, and (iv) deciphering signal transduction mechanisms. IMPORTANCE Critical bacterial processes, including motility, are influenced by c-di-GMP, which is controlled by environment-responsive synthetic and degradative enzymes. Because bacteria such as Vibrio fischeri use motility to colonize their hosts, understanding the roles of c-di-GMP-modulating enzymes in controlling motility has the potential to inform on microbe-host interactions. We leveraged recent advances in genetic manipulation to generate 50 mutants defective for putative c-di-GMP synthetic and degradative enzymes. We then assessed the consequences on motility, manipulating levels of magnesium and calcium, which inversely influenced motility and levels of c-di-GMP. Distinct subsets of the 50 genes were required under the different conditions. Our data thus provide needed insight into the functions of these enzymes and environmental factors that influence them.
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Affiliation(s)
| | - Ali Razvi
- Loyola University Chicago, Maywood, Illinois, USA
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43
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Reyes Ruiz LM, King KA, Agosto-Burgos C, Gamez IS, Gadda NC, Garrett EM, Tamayo R. Coordinated modulation of multiple processes through phase variation of a c-di-GMP phosphodiesterase in Clostridioides difficile. PLoS Pathog 2022; 18:e1010677. [PMID: 35789350 PMCID: PMC9286219 DOI: 10.1371/journal.ppat.1010677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 07/15/2022] [Accepted: 06/15/2022] [Indexed: 11/19/2022] Open
Abstract
The opportunistic nosocomial pathogen Clostridioides difficile exhibits phenotypic heterogeneity through phase variation, a stochastic, reversible process that modulates expression. In C. difficile, multiple sequences in the genome undergo inversion through site-specific recombination. Two such loci lie upstream of pdcB and pdcC, which encode phosphodiesterases (PDEs) that degrade the signaling molecule c-di-GMP. Numerous phenotypes are influenced by c-di-GMP in C. difficile including cell and colony morphology, motility, colonization, and virulence. In this study, we aimed to assess whether PdcB phase varies, identify the mechanism of regulation, and determine the effects on intracellular c-di-GMP levels and regulated phenotypes. We found that expression of pdcB is heterogeneous and the orientation of the invertible sequence, or ‘pdcB switch’, determines expression. The pdcB switch contains a promoter that when properly oriented promotes pdcB expression. Expression is augmented by an additional promoter upstream of the pdcB switch. Mutation of nucleotides at the site of recombination resulted in phase-locked strains with significant differences in pdcB expression. Characterization of these mutants showed that the pdcB locked-ON mutant has reduced intracellular c-di-GMP compared to the locked-OFF mutant, consistent with increased and decreased PdcB activity, respectively. These alterations in c-di-GMP had concomitant effects on multiple known c-di-GMP regulated processes, indicating that phase variation of PdcB allows C. difficile to coordinately diversify multiple phenotypes in the population to enhance survival. Phase variation is a mechanism by which many bacteria introduce phenotypic heterogeneity into a population as a bet-hedging strategy to help ensure survival under detrimental conditions. In C. difficile, the intracellular signaling molecule c-di-GMP regulates production of flagella, toxins, adhesins, and other factors that impact virulence. C. difficile encodes multiple c-di-GMP synthases and hydrolases that modulate intracellular c-di-GMPs and control these processes. Here, we show that production of a c-di-GMP hydrolytic enzyme, PdcB, undergoes phase variation in C. difficile. We generated phase-locked mutants unable to phase vary and found that PdcB affects global intracellular c-di-GMP levels, swimming and surface motility, and biofilm formation. These findings suggest that phase variation of PdcB enables C. difficile to coordinately regulate the production multiple factors by generating heterogeneity in intracellular c-di-GMP levels among bacteria in the population.
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Affiliation(s)
- Leila M. Reyes Ruiz
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Kathleen A. King
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Christian Agosto-Burgos
- Department of Pathology and Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Isabella S. Gamez
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Nicole C. Gadda
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Elizabeth M. Garrett
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Landgraf T, Völklein AE, Fürtig B, Schwalbe H. The cotranscriptional folding landscape for two cyclic di-nucleotide-sensing riboswitches with highly homologous aptamer domains acting either as ON- or OFF-switches. Nucleic Acids Res 2022; 50:6639-6655. [PMID: 35736222 PMCID: PMC9262584 DOI: 10.1093/nar/gkac514] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/03/2022] [Accepted: 06/07/2022] [Indexed: 12/24/2022] Open
Abstract
Riboswitches are gene regulatory elements located in untranslated mRNA regions. They bind inducer molecules with high affinity and specificity. Cyclic-di-nucleotide-sensing riboswitches are major regulators of genes for the environment, membranes and motility (GEMM) of bacteria. Up to now, structural probing assays or crystal structures have provided insight into the interaction between cyclic-di-nucleotides and their corresponding riboswitches. ITC analysis, NMR analysis and computational modeling allowed us to gain a detailed understanding of the gene regulation mechanisms for the Cd1 (Clostridium difficile) and for the pilM (Geobacter metallireducens) riboswitches and their respective di-nucleotides c-di-GMP and c-GAMP. Binding capability showed a 25 nucleotide (nt) long window for pilM and a 61 nt window for Cd1. Within this window, binding affinities ranged from 35 μM to 0.25 μM spanning two orders of magnitude for Cd1 and pilM showing a strong dependence on competing riboswitch folds. Experimental results were incorporated into a Markov simulation to further our understanding of the transcriptional folding pathways of riboswitches. Our model showed the ability to predict riboswitch gene regulation and its dependence on transcription speed, pausing and ligand concentration.
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Affiliation(s)
| | | | - Boris Fürtig
- Correspondence may also be addressed to Boris Fürtig.
| | - Harald Schwalbe
- To whom correspondence should be addressed. Tel: +49 69 798 29737; Fax: +49 69 798 29515;
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Teschler JK, Nadell CD, Drescher K, Yildiz FH. Mechanisms Underlying Vibrio cholerae Biofilm Formation and Dispersion. Annu Rev Microbiol 2022; 76:503-532. [PMID: 35671532 DOI: 10.1146/annurev-micro-111021-053553] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Biofilms are a widely observed growth mode in which microbial communities are spatially structured and embedded in a polymeric extracellular matrix. Here, we focus on the model bacterium Vibrio cholerae and summarize the current understanding of biofilm formation, including initial attachment, matrix components, community dynamics, social interactions, molecular regulation, and dispersal. The regulatory network that orchestrates the decision to form and disperse from biofilms coordinates various environmental inputs. These cues are integrated by several transcription factors, regulatory RNAs, and second-messenger molecules, including bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP). Through complex mechanisms, V. cholerae weighs the energetic cost of forming biofilms against the benefits of protection and social interaction that biofilms provide. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Jennifer K Teschler
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA;
| | - Carey D Nadell
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | | | - Fitnat H Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, California, USA;
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Sanbonmatsu K. Getting to the bottom of lncRNA mechanism: structure-function relationships. Mamm Genome 2022; 33:343-353. [PMID: 34642784 PMCID: PMC8509902 DOI: 10.1007/s00335-021-09924-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/28/2021] [Indexed: 12/14/2022]
Abstract
While long non-coding RNAs are known to play key roles in disease and development, relatively few structural studies have been performed for this important class of RNAs. Here, we review functional studies of long non-coding RNAs and expose the need for high-resolution 3-D structural studies, discussing the roles of long non-coding RNAs in the cell and how structure-function relationships might be used to elucidate further understanding. We then describe structural studies of other classes of RNAs using chemical probing, nuclear magnetic resonance, small-angle X-ray scattering, X-ray crystallography, and cryogenic electron microscopy (cryo-EM). Next, we review early structural studies of long non-coding RNAs to date and describe the way forward for the structural biology of long non-coding RNAs in terms of cryo-EM.
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47
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Chen Y, Lv M, Liang Z, Liu Z, Zhou J, Zhang L. Cyclic di-GMP modulates sessile-motile phenotypes and virulence in Dickeya oryzae via two PilZ domain receptors. MOLECULAR PLANT PATHOLOGY 2022; 23:870-884. [PMID: 35254732 PMCID: PMC9104268 DOI: 10.1111/mpp.13200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/23/2022] [Accepted: 02/08/2022] [Indexed: 05/03/2023]
Abstract
Dickeya oryzae is a bacterial pathogen causing the severe rice stem rot disease in China and other rice-growing countries. We showed recently that the universal bacterial second messenger c-di-GMP plays an important role in modulation of bacterial motility and pathogenicity, but the mechanism of regulation remains unknown. In this study, bioinformatics analysis of the D. oryzae EC1 genome led to the identification of two proteins, YcgR and BcsA, both of which contain a conserved c-di-GMP receptor domain, known as the PilZ-domain. By deleting all the genes encoding c-di-GMP-degrading enzymes in D. oryzae EC1, the resultant mutant 7ΔPDE with high c-di-GMP levels became nonmotile, formed hyperbiofilm, and lost the ability to colonize and invade rice seeds. These phenotypes were partially reversed by deletion of ycgR in the mutant 7ΔPDE, whereas deletion of bcsA only reversed the hyperbiofilm phenotype of mutant 7ΔPDE. Significantly, double deletion of ycgR and bcsA in mutant 7ΔPDE rescued its motility, biofilm formation, and virulence to levels of wild-type EC1. In vitro biochemical experiments and in vivo phenotypic assays further validated that YcgR and BcsA proteins are the receptors for c-di-GMP, which together play a critical role in regulating the c-di-GMP-associated functionality. The findings from this study fill a gap in our understanding of how c-di-GMP modulates bacterial motility and biofilm formation, and provide useful clues for further elucidation of sophisticated virulence regulatory mechanisms in this important plant pathogen.
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Affiliation(s)
- Yufan Chen
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
| | - Mingfa Lv
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
| | - Zhibin Liang
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
| | - Zhiqing Liu
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
| | - Jianuan Zhou
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
| | - Lian‐Hui Zhang
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
- Guangdong Province Key Laboratory of Microbial Signals and Disease ControlIntegrative Microbiology Research CenterSouth China Agricultural UniversityGuangzhouChina
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Hamal Dhakal S, Panchapakesan SSS, Slattery P, Roth A, Breaker RR. Variants of the guanine riboswitch class exhibit altered ligand specificities for xanthine, guanine, or 2'-deoxyguanosine. Proc Natl Acad Sci U S A 2022; 119:e2120246119. [PMID: 35622895 PMCID: PMC9295807 DOI: 10.1073/pnas.2120246119] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/12/2022] [Indexed: 12/30/2022] Open
Abstract
The aptamer portions of previously reported riboswitch classes that sense guanine, adenine, or 2′-deoxyguanosine are formed by a highly similar three-stem junction with distinct nucleotide sequences in the regions joining the stems. The nucleotides in these joining regions form the major features of the selective ligand-binding pocket for each aptamer. Previously, we reported the existence of additional, rare variants of the predominant guanine-sensing riboswitch class that carry nucleotide differences in the ligand-binding pocket, suggesting that these RNAs have further diversified their structures and functions. Herein, we report the discovery and analysis of three naturally occurring variants of guanine riboswitches that are narrowly distributed across Firmicutes. These RNAs were identified using comparative sequence analysis methods, which also revealed that some of the gene associations for these variants are atypical for guanine riboswitches or their previously known natural variants. Binding assays demonstrate that the newfound variant riboswitch representatives recognize xanthine, guanine, or 2′-deoxyguanosine, with the guanine class exhibiting greater discrimination against related purines than the more common guanine riboswitch class reported previously. These three additional variant classes, together with the four previously discovered riboswitch classes that employ the same three-stem junction architecture, reveal how a simple structural framework can be diversified to expand the range of purine-based ligands sensed by RNA.
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Affiliation(s)
- Siddhartha Hamal Dhakal
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103
| | | | - Paul Slattery
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103
| | - Adam Roth
- HHMI, Yale University, New Haven, CT 06520-8103
| | - Ronald R. Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103
- HHMI, Yale University, New Haven, CT 06520-8103
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103
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Diguanylate Cyclase (DGC) Implicated in the Synthesis of Multiple Bacteriocins via the Flagellar-Type III Secretion System Produced by Pectobacterium carotovorum subsp. carotovorum. Int J Mol Sci 2022; 23:ijms23105649. [PMID: 35628457 PMCID: PMC9144310 DOI: 10.3390/ijms23105649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/09/2022] [Accepted: 05/16/2022] [Indexed: 11/16/2022] Open
Abstract
The plant pathogen Pectobacterium carotovorum subsp. carotovorum (previously Erwinia carotovora subsp. carotovora) causes soft rot and stem rot diseases in a variety of crops, including Chinese cabbage, potato, and tomato. The flagellar-type III secretion systems were used by Pcc’s virulence mechanism to export proteins or bacteriocins to the outside of the cell. DGC, a virulence factor that cyclizes c-di-GMP, a common secondary signal in physiological processes and toxin control systems of many bacteria, was discovered in Pcc’s genomic DNA. The dgc gene in Pcc was blocked using the method of homologous recombination in our study. In the in vivo setting, the results demonstrated that the dgc knockout strain does not release low molecular weight bacteriocins. The bacteriocin gene (carocin S2, carocin S3, carocin S4) and the flagellar-type III secretion system genes were also unable to be transcribed by the dgc knockout strain in the transcription experiment. We also observed that the amount of bacteriocin expressed changed when the amount of L-glutamine in the environment exceeded a particular level. These data suggested that L-glutamine influenced physiological processes in Pcc strains in some way. We hypothesized a relationship between dgc and the genes involved in Pcc LMWB external export via the flagellar-type secretion system based on these findings. In this study, the current findings led us to propose a mechanism in which DGC’s cyclic di-GMP might bind to receptor proteins and positively regulate bacteriocin transcription as well as the synthesis, mobility, and transport of toxins.
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50
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Marchand B, Ponty Y, Bulteau L. Tree diet: reducing the treewidth to unlock FPT algorithms in RNA bioinformatics. Algorithms Mol Biol 2022; 17:8. [PMID: 35366923 PMCID: PMC8976393 DOI: 10.1186/s13015-022-00213-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/01/2022] [Indexed: 11/25/2022] Open
Abstract
Hard graph problems are ubiquitous in Bioinformatics, inspiring the design of specialized Fixed-Parameter Tractable algorithms, many of which rely on a combination of tree-decomposition and dynamic programming. The time/space complexities of such approaches hinge critically on low values for the treewidth tw of the input graph. In order to extend their scope of applicability, we introduce the Tree-Diet problem, i.e. the removal of a minimal set of edges such that a given tree-decomposition can be slimmed down to a prescribed treewidth \documentclass[12pt]{minimal}
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\begin{document}$$tw'$$\end{document}tw′. Our rationale is that the time gained thanks to a smaller treewidth in a parameterized algorithm compensates the extra post-processing needed to take deleted edges into account. Our core result is an FPT dynamic programming algorithm for Tree-Diet, using \documentclass[12pt]{minimal}
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\begin{document}$$2^{O(tw)}n$$\end{document}2O(tw)n time and space. We complement this result with parameterized complexity lower-bounds for stronger variants (e.g., NP-hardness when \documentclass[12pt]{minimal}
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\begin{document}$$tw'$$\end{document}tw′ or \documentclass[12pt]{minimal}
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\begin{document}$$tw-tw'$$\end{document}tw-tw′ is constant). We propose a prototype implementation for our approach which we apply on difficult instances of selected RNA-based problems: RNA design, sequence-structure alignment, and search of pseudoknotted RNAs in genomes, revealing very encouraging results. This work paves the way for a wider adoption of tree-decomposition-based algorithms in Bioinformatics.
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