1
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Bastet L, Korepanov AP, Jagodnik J, Grondin JP, Lamontagne AM, Guillier M, Lafontaine DA. Riboswitch and small RNAs modulate btuB translation initiation in Escherichia coli and trigger distinct mRNA regulatory mechanisms. Nucleic Acids Res 2024; 52:5852-5865. [PMID: 38742638 DOI: 10.1093/nar/gkae347] [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: 05/01/2023] [Revised: 03/19/2024] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
Small RNAs (sRNAs) and riboswitches represent distinct classes of RNA regulators that control gene expression upon sensing metabolic or environmental variations. While sRNAs and riboswitches regulate gene expression by affecting mRNA and protein levels, existing studies have been limited to the characterization of each regulatory system in isolation, suggesting that sRNAs and riboswitches target distinct mRNA populations. We report that the expression of btuB in Escherichia coli, which is regulated by an adenosylcobalamin (AdoCbl) riboswitch, is also controlled by the small RNAs OmrA and, to a lesser extent, OmrB. Strikingly, we find that the riboswitch and sRNAs reduce mRNA levels through distinct pathways. Our data show that while the riboswitch triggers Rho-dependent transcription termination, sRNAs rely on the degradosome to modulate mRNA levels. Importantly, OmrA pairs with the btuB mRNA through its central region, which is not conserved in OmrB, indicating that these two sRNAs may have specific targets in addition to their common regulon. In contrast to canonical sRNA regulation, we find that OmrA repression of btuB is lost using an mRNA binding-deficient Hfq variant. Together, our study demonstrates that riboswitch and sRNAs modulate btuB expression, providing an example of cis- and trans-acting RNA-based regulatory systems maintaining cellular homeostasis.
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Affiliation(s)
- Laurène Bastet
- Department of Biology, Faculty of Science, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Alexey P Korepanov
- Expression Génétique Microbienne, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005Paris, France
| | - Jonathan Jagodnik
- Expression Génétique Microbienne, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005Paris, France
| | - Jonathan P Grondin
- Department of Biology, Faculty of Science, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Anne-Marie Lamontagne
- Department of Biology, Faculty of Science, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Maude Guillier
- Expression Génétique Microbienne, UMR8261 CNRS, Université Paris Cité, Institut de Biologie Physico-Chimique, 75005Paris, France
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Science, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
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2
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Zhu Y, Ponath F, Cosi V, Vogel J. A global survey of small RNA interactors identifies KhpA and KhpB as major RNA-binding proteins in Fusobacterium nucleatum. Nucleic Acids Res 2024; 52:3950-3970. [PMID: 38281181 DOI: 10.1093/nar/gkae010] [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: 10/30/2023] [Revised: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 01/30/2024] Open
Abstract
The common oral microbe Fusobacterium nucleatum has recently drawn attention after it was found to colonize tumors throughout the human body. Fusobacteria are also interesting study systems for bacterial RNA biology as these early-branching species encode many small noncoding RNAs (sRNAs) but lack homologs of the common RNA-binding proteins (RBPs) CsrA, Hfq and ProQ. To search for alternate sRNA-associated RBPs in F. nucleatum, we performed a systematic mass spectrometry analysis of proteins that co-purified with 19 different sRNAs. This approach revealed strong enrichment of the KH domain proteins KhpA and KhpB with nearly all tested sRNAs, including the σE-dependent sRNA FoxI, a regulator of several envelope proteins. KhpA/B act as a dimer to bind sRNAs with low micromolar affinity and influence the stability of several of their target transcripts. Transcriptome studies combined with biochemical and genetic analyses suggest that KhpA/B have several physiological functions, including being required for ethanolamine utilization. Our RBP search and the discovery of KhpA/B as major RBPs in F. nucleatum are important first steps in identifying key players of post-transcriptional control at the root of the bacterial phylogenetic tree.
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Affiliation(s)
- Yan Zhu
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg D-97080, Germany
| | - Falk Ponath
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg D-97080, Germany
| | - Valentina Cosi
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg D-97080, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg D-97080, Germany
- Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
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3
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Stibelman AY, Sariles AY, Takahashi MK. Beyond membrane permeability: A role for the small RNA MicF in regulation of chromosome replication and partitioning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.22.590647. [PMID: 38712278 PMCID: PMC11071386 DOI: 10.1101/2024.04.22.590647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Small regulatory RNAs (sRNA) have been shown to play a large role in the management of stress responses in Escherichia coli and other bacteria. sRNAs act post-transcriptionally on target mRNA through an imperfect base pairing mechanism to regulate downstream protein expression. The imperfect base pairing allows a single sRNA to bind and regulate a variety mRNA targets which can form intricate regulatory networks that connect different physiological processes for the cell's response. Upon exposure to antimicrobials and superoxide generating agents, the MicF sRNA in E. coli has been shown to regulate a small set of genes involved in the management of membrane permeability. Currently, it is unknown whether MicF acts on other processes to mediate the response to these agents. Using an sRNA interaction prediction tool, we identified genes in E. coli that are potentially regulated by MicF. Through subsequent analysis using a sfGFP-based reporter-gene fusion, we have validated two novel targets of MicF regulation: SeqA, a negative modulator of DNA replication, and ObgE, a GTPase crucial for chromosome partitioning. Importantly, the interaction between MicF and these target mRNAs is contingent upon the presence of the RNA chaperone protein, Hfq. Furthermore, our findings affirm the role of MicF's conserved 5' seed pairing region in initiating these regulatory interactions. Our study suggests that, beyond its established role in membrane permeability management, MicF exerts control over chromosome dynamics in response to distinct environmental cues, implicating a more multifaceted regulatory function in bacterial stress adaptation.
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4
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Wang N, Sheng Y, Liu Y, Guo Y, He J, Liu J. Cryo-EM structures of Mycobacterium tuberculosis polynucleotide phosphorylase suggest a potential mechanism for its RNA substrate degradation. Arch Biochem Biophys 2024; 754:109917. [PMID: 38395123 DOI: 10.1016/j.abb.2024.109917] [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: 12/09/2023] [Revised: 01/25/2024] [Accepted: 01/28/2024] [Indexed: 02/25/2024]
Abstract
As one of the oldest infectious diseases in the world, tuberculosis (TB) is the second most deadly infectious disease after COVID-19. Tuberculosis is caused by Mycobacterium tuberculosis (Mtb), which can attack various organs of the human body. Up to now, drug-resistant TB continues to be a public health threat. Pyrazinamide (PZA) is regarded as a sterilizing drug in the treatment of TB due to its distinct ability to target Mtb persisters. Previously we demonstrated that a D67N mutation in Mycobacterium tuberculosis polynucleotide phosphorylase (MtbPNPase, Rv2783c) confers resistance to PZA and Rv2783c is a potential target for PZA, but the mechanism leading to PZA resistance remains unclear. To gain further insight into the MtbPNPase, we determined the cryo-EM structures of apo Rv2783c, its mutant form and its complex with RNA. Our studies revealed the Rv2783c structure at atomic resolution and identified its enzymatic functional groups essential for its phosphorylase activities. We also investigated the molecular mechanisms underlying the resistance to PZA conferred by the mutation. Our research findings provide structural and functional insights enabling the development of new anti-tuberculosis drugs.
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Affiliation(s)
- Na Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China; State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
| | - Yanan Sheng
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China; State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Yutong Liu
- Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Yaoting Guo
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Jun He
- Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Jinsong Liu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China; State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China; Guangdong Provincial Key Laboratory of Biocomputing, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
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5
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Małecka EM, Woodson SA. RNA compaction and iterative scanning for small RNA targets by the Hfq chaperone. Nat Commun 2024; 15:2069. [PMID: 38453956 PMCID: PMC10920880 DOI: 10.1038/s41467-024-46316-6] [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: 10/24/2023] [Accepted: 02/18/2024] [Indexed: 03/09/2024] Open
Abstract
RNA-guided enzymes must quickly search a vast sequence space for their targets. This search is aided by chaperones such as Hfq, a protein that mediates regulation by bacterial small RNAs (sRNAs). How RNA binding proteins enhance this search is little known. Using single-molecule Förster resonance energy transfer, we show that E. coli Hfq performs a one-dimensional scan in which compaction of the target RNA delivers sRNAs to sites distant from the location of Hfq recruitment. We also show that Hfq can transfer an sRNA between different target sites in a single mRNA, favoring the most stable duplex. We propose that compaction and segmental transfer, combined with repeated cycles of base pairing, enable the kinetic selection of optimal sRNA targets. Finally, we show that RNA compaction and sRNA transfer require conserved arginine patches. We suggest that arginine patches are a widespread strategy for enabling the movement of RNA across protein surfaces.
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Affiliation(s)
- Ewelina M Małecka
- Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St.,5, Baltimore, MD, 21218, USA.
- Laboratory of Single-Molecule Biophysics, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, Warsaw, 02-109, Poland.
| | - Sarah A Woodson
- Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St.,5, Baltimore, MD, 21218, USA.
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6
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Bárria C, Athayde D, Hernandez G, Fonseca L, Casinhas J, Cordeiro TN, Archer M, Arraiano CM, Brito JA, Matos RG. Structure and function of Campylobacter jejuni polynucleotide phosphorylase (PNPase): Insights into the role of this RNase in pathogenicity. Biochimie 2024; 216:56-70. [PMID: 37806617 DOI: 10.1016/j.biochi.2023.10.006] [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: 07/24/2023] [Revised: 09/29/2023] [Accepted: 10/06/2023] [Indexed: 10/10/2023]
Abstract
Ribonucleases are in charge of the processing, degradation and quality control of all cellular transcripts, which makes them crucial factors in RNA regulation. This post-transcriptional regulation allows bacteria to promptly react to different stress conditions and growth phase transitions, and also to produce the required virulence factors in pathogenic bacteria. Campylobacter jejuni is the main responsible for human gastroenteritis in the world. In this foodborne pathogen, exoribonuclease PNPase (CjPNP) is essential for low-temperature cell survival, affects the synthesis of proteins involved in virulence and has an important role in swimming, cell adhesion/invasion ability, and chick colonization. Here we report the crystallographic structure of CjPNP, complemented with SAXS, which confirms the characteristic doughnut-shaped trimeric arrangement and evaluates domain arrangement and flexibility. Mutations in highly conserved residues were constructed to access their role in RNA degradation and polymerization. Surprisingly, we found two mutations that altered CjPNP into a protein that is only capable of degrading RNA even in conditions that favour polymerization. These findings will be important to develop new strategies to combat C. jejuni infections.
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Affiliation(s)
- Cátia Bárria
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Diogo Athayde
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Guillem Hernandez
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Leonor Fonseca
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Jorge Casinhas
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Tiago N Cordeiro
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Margarida Archer
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Cecília M Arraiano
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - José A Brito
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
| | - Rute G Matos
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Avenida da República, 2780-157, Oeiras, Portugal.
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7
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Sneideris T, Erkamp NA, Ausserwöger H, Saar KL, Welsh TJ, Qian D, Katsuya-Gaviria K, Johncock MLLY, Krainer G, Borodavka A, Knowles TPJ. Targeting nucleic acid phase transitions as a mechanism of action for antimicrobial peptides. Nat Commun 2023; 14:7170. [PMID: 37935659 PMCID: PMC10630377 DOI: 10.1038/s41467-023-42374-4] [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: 01/18/2023] [Accepted: 10/10/2023] [Indexed: 11/09/2023] Open
Abstract
Antimicrobial peptides (AMPs), which combat bacterial infections by disrupting the bacterial cell membrane or interacting with intracellular targets, are naturally produced by a number of different organisms, and are increasingly also explored as therapeutics. However, the mechanisms by which AMPs act on intracellular targets are not well understood. Using machine learning-based sequence analysis, we identified a significant number of AMPs that have a strong tendency to form liquid-like condensates in the presence of nucleic acids through phase separation. We demonstrate that this phase separation propensity is linked to the effectiveness of the AMPs in inhibiting transcription and translation in vitro, as well as their ability to compact nucleic acids and form clusters with bacterial nucleic acids in bacterial cells. These results suggest that the AMP-driven compaction of nucleic acids and modulation of their phase transitions constitute a previously unrecognised mechanism by which AMPs exert their antibacterial effects. The development of antimicrobials that target nucleic acid phase transitions may become an attractive route to finding effective and long-lasting antibiotics.
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Affiliation(s)
- Tomas Sneideris
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Nadia A Erkamp
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Hannes Ausserwöger
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Kadi L Saar
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Timothy J Welsh
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Daoyuan Qian
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Kai Katsuya-Gaviria
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
| | - Margaret L L Y Johncock
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Georg Krainer
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK
| | - Alexander Borodavka
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK.
| | - Tuomas P J Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Ave, Cambridge, UK.
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8
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Falchi FA, Forti F, Carnelli C, Genco A, Pizzoccheri R, Manzari C, Pavesi G, Briani F. Human PNPase causes RNA stabilization and accumulation of R-loops in the Escherichia coli model system. Sci Rep 2023; 13:11771. [PMID: 37479726 PMCID: PMC10362022 DOI: 10.1038/s41598-023-38924-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/17/2023] [Indexed: 07/23/2023] Open
Abstract
Polyribonucleotide phosphorylase (PNPase) is a phosphorolytic RNA exonuclease highly conserved throughout evolution. In Escherichia coli, PNPase controls complex phenotypic traits like biofilm formation and growth at low temperature. In human cells, PNPase is located in mitochondria, where it is implicated in the RNA import from the cytoplasm, the mitochondrial RNA degradation and the processing of R-loops, namely stable RNA-DNA hybrids displacing a DNA strand. In this work, we show that the human PNPase (hPNPase) expressed in E. coli causes oxidative stress, SOS response activation and R-loops accumulation. Hundreds of E. coli RNAs are stabilized in presence of hPNPase, whereas only few transcripts are destabilized. Moreover, phenotypic traits typical of E. coli strains lacking PNPase are strengthened in presence of the human enzyme. We discuss the hypothesis that hPNPase expressed in E. coli may bind, but not degrade, the RNA, in agreement with previous in vitro data showing that phosphate concentrations in the range of those found in the bacterial cytoplasm and, more relevant, in the mitochondria, inhibit its activity.
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Affiliation(s)
- Federica A Falchi
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Francesca Forti
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Cristina Carnelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Aurelia Genco
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Roberto Pizzoccheri
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy
| | - Caterina Manzari
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari "Aldo Moro", 70121, Bari, Italy
| | - Giulio Pavesi
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy.
| | - Federica Briani
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133, Milan, Italy.
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9
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Schilder A, Görke B. Role of the 5' end phosphorylation state for small RNA stability and target RNA regulation in bacteria. Nucleic Acids Res 2023; 51:5125-5143. [PMID: 36987877 PMCID: PMC10250213 DOI: 10.1093/nar/gkad226] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/28/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
In enteric bacteria, several small RNAs (sRNAs) including MicC employ endoribonuclease RNase E to stimulate target RNA decay. A current model proposes that interaction of the sRNA 5' monophosphate (5'P) with the N-terminal sensing pocket of RNase E allosterically activates cleavage of the base-paired target in the active site. In vivo evidence supporting this model is lacking. Here, we engineered a genetic tool allowing us to generate 5' monophosphorylated sRNAs of choice in a controllable manner in the cell. Four sRNAs were tested and none performed better in target destabilization when 5' monophosphorylated. MicC retains full activity even when RNase E is defective in 5'P sensing, whereas regulation is lost upon removal of its scaffolding domain. Interestingly, sRNAs MicC and RyhB that originate with a 5' triphosphate group are dramatically destabilized when 5' monophosphorylated, but stable when in 5' triphosphorylated form. In contrast, the processing-derived sRNAs CpxQ and SroC, which carry 5'P groups naturally, are highly stable. Thus, the 5' phosphorylation state determines stability of naturally triphosphorylated sRNAs, but plays no major role for target RNA destabilization in vivo. In contrast, the RNase E C-terminal half is crucial for MicC-mediated ompD decay, suggesting that interaction with Hfq is mandatory.
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Affiliation(s)
- Alexandra Schilder
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
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10
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Wu N, Zhang Y, Zhang S, Yuan Y, Liu S, Xu T, Cui P, Zhang W, Zhang Y. Polynucleotide Phosphorylase Mediates a New Mechanism of Persister Formation in Escherichia coli. Microbiol Spectr 2023; 11:e0154622. [PMID: 36475972 PMCID: PMC9927094 DOI: 10.1128/spectrum.01546-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Despite the identification of many genes and pathways involved in the persistence phenomenon in bacteria, the mechanisms of persistence are not well understood. Here, using Escherichia coli, we identified polynucleotide phosphorylase (PNPase) as a key regulator of persister formation. We constructed the pnp knockout strain (Δpnp) and its complemented strain and exposed them to antibiotics and stress conditions. The results showed that, compared with the wild-type strain W3110, the Δpnp strain had significant defects in persistence to antibiotics and stresses, and the persistence phenotype was restored upon complementation with the pnp gene. Transcriptome sequencing (RNA-seq) analysis revealed that 242 (166 upregulated and 76 downregulated) genes were differentially expressed in the Δpnp strain compared with the W3110 strain. KEGG analysis of the upregulated genes showed that these genes were mostly mapped to metabolism and virulence pathways, of which most are positively regulated by the global regulator cyclic AMP receptor protein (CRP). Correspondingly, the transcription level of the crp gene in the Δpnp strain increased 3.22-fold in the early stationary phase. We further explored the indicators of cellular metabolism of the Δpnp strain, the phenotype of the pnp and crp double-deletion mutant, and the transcriptional activity of the crp gene. Our results indicate that PNPase controls cellular metabolism by negatively regulating the crp operon via targeting the 5'-untranslated region of the crp transcript. This study reveals a persister mechanism and provides novel targets for the development of drugs against persisters for more effective treatment. IMPORTANCE Persisters pose significant challenges for a more effective treatment of persistent infections. An improved understanding of mechanisms of persistence will provide therapeutic targets important for the development of better treatments. Since recent studies with the key tuberculosis persister drug pyrazinamide have implicated polynucleotide phosphorylase (PNPase) as a drug target, in this study, we addressed the possibility that PNPase might be involved in persistence in Escherichia coli. Our study demonstrates PNPase indeed being involved in persistence, provides a mechanism by which PNPase controls persister formation, and suggests a new therapeutic target for treating persistent bacterial infections.
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Affiliation(s)
- Nan Wu
- Department of Clinical Laboratory, Shanghai Stomatological Hospital, Shanghai, China
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Yumeng Zhang
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Shanshan Zhang
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Youhua Yuan
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Shuang Liu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Tao Xu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Peng Cui
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Wenhong Zhang
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Ying Zhang
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
- State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Dendooven T, Sonnleitner E, Bläsi U, Luisi BF. Translational regulation by Hfq-Crc assemblies emerges from polymorphic ribonucleoprotein folding. EMBO J 2023; 42:e111129. [PMID: 36504222 PMCID: PMC9890229 DOI: 10.15252/embj.2022111129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/25/2022] [Accepted: 11/11/2022] [Indexed: 12/14/2022] Open
Abstract
The widely occurring bacterial RNA chaperone Hfq is a key factor in the post-transcriptional control of hundreds of genes in Pseudomonas aeruginosa. How this broadly acting protein can contribute to the regulatory requirements of many different genes remains puzzling. Here, we describe cryo-EM structures of higher order assemblies formed by Hfq and its partner protein Crc on control regions of different P. aeruginosa target mRNAs. Our results show that these assemblies have mRNA-specific quaternary architectures resulting from the combination of multivalent protein-protein interfaces and recognition of patterns in the RNA sequence. The structural polymorphism of these ribonucleoprotein assemblies enables selective translational repression of many different target mRNAs. This system elucidates how highly complex regulatory pathways can evolve with a minimal economy of proteinogenic components in combination with RNA sequence and fold.
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Affiliation(s)
- Tom Dendooven
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Elisabeth Sonnleitner
- Department of Microbiology, Immunobiology and Genetics, Max Perutz LabsUniversity of ViennaViennaAustria
| | - Udo Bläsi
- Department of Microbiology, Immunobiology and Genetics, Max Perutz LabsUniversity of ViennaViennaAustria
| | - Ben F Luisi
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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12
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Target recognition by RNase E RNA-binding domain AR2 drives sRNA decay in the absence of PNPase. Proc Natl Acad Sci U S A 2022; 119:e2208022119. [PMID: 36409892 PMCID: PMC9860253 DOI: 10.1073/pnas.2208022119] [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] [Indexed: 11/22/2022] Open
Abstract
The C-terminal domain (CTD) of the major endoribonuclease RNase E not only serves as a scaffold for the central RNA decay machinery in gram-negative bacteria but also mediates coupled degradation of small regulatory RNAs (sRNAs) and their cognate target transcripts following RNA chaperone Hfq-facilitated sRNA-mRNA base pairing. Despite the crucial role of RNase E CTD in sRNA-dependent gene regulation, the contribution of particular residues within this domain in recruiting sRNAs and mRNAs upon base pairing remains unknown. We have previously shown that in Escherichia coli, the highly conserved 3'-5'-exoribonuclease polynucleotide phosphorylase (PNPase) paradoxically stabilizes sRNAs by limiting access of RNase E to Hfq-bound sRNAs and by degrading target mRNA fragments that would otherwise promote sRNA decay. Here, we report that in the absence of PNPase, the RNA-binding region AR2 in the CTD is required for RNase E to initiate degradation of the Hfq-dependent sRNAs CyaR and RyhB. Additionally, we show that introducing mutations in either hfq that disrupts target mRNA binding to Hfq or the AR2 coding region of rne impairs RNase E binding to sRNAs. Altogether, our data support a model where sRNAs are recruited via bound mRNA targets to RNase E by its AR2 domain after Hfq catalyzes sRNA-mRNA pairing. These results also support our conclusion that in a PNPase-deficient strain, more rapid decay of sRNAs occurs due to accelerated pairing with mRNA targets as a consequence of their accumulation. Our findings provide insights into the mechanisms by which sRNAs and mRNAs are regulated by RNase E.
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13
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Smirnov A. How global RNA-binding proteins coordinate the behaviour of RNA regulons: an information approach. Comput Struct Biotechnol J 2022; 20:6317-6338. [DOI: 10.1016/j.csbj.2022.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022] Open
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14
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How RNases Shape Mitochondrial Transcriptomes. Int J Mol Sci 2022; 23:ijms23116141. [PMID: 35682820 PMCID: PMC9181182 DOI: 10.3390/ijms23116141] [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: 05/02/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are the power houses of eukaryote cells. These endosymbiotic organelles of prokaryote origin are considered as semi-autonomous since they have retained a genome and fully functional gene expression mechanisms. These pathways are particularly interesting because they combine features inherited from the bacterial ancestor of mitochondria with characteristics that appeared during eukaryote evolution. RNA biology is thus particularly diverse in mitochondria. It involves an unexpectedly vast array of factors, some of which being universal to all mitochondria and others being specific from specific eukaryote clades. Among them, ribonucleases are particularly prominent. They play pivotal functions such as the maturation of transcript ends, RNA degradation and surveillance functions that are required to attain the pool of mature RNAs required to synthesize essential mitochondrial proteins such as respiratory chain proteins. Beyond these functions, mitochondrial ribonucleases are also involved in the maintenance and replication of mitochondrial DNA, and even possibly in the biogenesis of mitochondrial ribosomes. The diversity of mitochondrial RNases is reviewed here, showing for instance how in some cases a bacterial-type enzyme was kept in some eukaryotes, while in other clades, eukaryote specific enzymes were recruited for the same function.
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15
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Falchi FA, Pizzoccheri R, Briani F. Activity and Function in Human Cells of the Evolutionary Conserved Exonuclease Polynucleotide Phosphorylase. Int J Mol Sci 2022; 23:ijms23031652. [PMID: 35163574 PMCID: PMC8836086 DOI: 10.3390/ijms23031652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
Polynucleotide phosphorylase (PNPase) is a phosphorolytic RNA exonuclease highly conserved throughout evolution. Human PNPase (hPNPase) is located in mitochondria and is essential for mitochondrial function and homeostasis. Not surprisingly, mutations in the PNPT1 gene, encoding hPNPase, cause serious diseases. hPNPase has been implicated in a plethora of processes taking place in different cell compartments and involving other proteins, some of which physically interact with hPNPase. This paper reviews hPNPase RNA binding and catalytic activity in relation with the protein structure and in comparison, with the activity of bacterial PNPases. The functions ascribed to hPNPase in different cell compartments are discussed, highlighting the gaps that still need to be filled to understand the physiological role of this ancient protein in human cells.
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16
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Olejniczak M, Jiang X, Basczok MM, Storz G. KH domain proteins: Another family of bacterial RNA matchmakers? Mol Microbiol 2022; 117:10-19. [PMID: 34748246 PMCID: PMC8766902 DOI: 10.1111/mmi.14842] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 01/03/2023]
Abstract
In many bacteria, the stabilities and functions of small regulatory RNAs (sRNAs) that act by base pairing with target RNAs most often are dependent on Hfq or ProQ/FinO-domain proteins, two classes of RNA chaperone proteins. However, while all bacteria appear to have sRNAs, many have neither Hfq nor ProQ/FinO-domain proteins raising the question of whether another factor might act as an sRNA chaperone in these organisms. Several recent studies have reported that KH domain proteins, such as KhpA and KhpB, bind sRNAs. Here we describe what is known about the distribution, structures, RNA-binding properties, and physiologic roles of KhpA and KhpB and discuss evidence for and against these proteins serving as sRNAs chaperones.
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Affiliation(s)
- Mikolaj Olejniczak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Xiaofang Jiang
- Intramural Research Program, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Maciej M. Basczok
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institutes of Child Health and Human Development, Bethesda, MD 20892-4417, USA
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17
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Katsuya-Gaviria K, Paris G, Dendooven T, Bandyra KJ. Bacterial RNA chaperones and chaperone-like riboregulators: behind the scenes of RNA-mediated regulation of cellular metabolism. RNA Biol 2021; 19:419-436. [PMID: 35438047 PMCID: PMC9037510 DOI: 10.1080/15476286.2022.2048565] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/26/2022] [Indexed: 11/02/2022] Open
Abstract
In all domains of life, RNA chaperones safeguard and guide the fate of the cellular RNA pool. RNA chaperones comprise structurally diverse proteins that ensure proper folding, stability, and ribonuclease resistance of RNA, and they support regulatory activities mediated by RNA. RNA chaperones constitute a topologically diverse group of proteins that often present an unstructured region and bind RNA with limited nucleotide sequence preferences. In bacteria, three main proteins - Hfq, ProQ, and CsrA - have been shown to regulate numerous complex processes, including bacterial growth, stress response and virulence. Hfq and ProQ have well-studied activities as global chaperones with pleiotropic impact, while CsrA has a chaperone-like role with more defined riboregulatory function. Here, we describe relevant novel insights into their common features, including RNA binding properties, unstructured domains, and interplay with other proteins important to RNA metabolism.
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Affiliation(s)
- Kai Katsuya-Gaviria
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CambridgeCB2 1GA, UK
| | - Giulia Paris
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CambridgeCB2 1GA, UK
| | - Tom Dendooven
- Department of Structural Studies, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Katarzyna J. Bandyra
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, 02-089Warsaw, Poland
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18
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Islam MS, Bandyra KJ, Chao Y, Vogel J, Luisi BF. Impact of pseudouridylation, substrate fold, and degradosome organization on the endonuclease activity of RNase E. RNA (NEW YORK, N.Y.) 2021; 27:1339-1352. [PMID: 34341070 PMCID: PMC8522691 DOI: 10.1261/rna.078840.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
The conserved endoribonuclease RNase E dominates the dynamic landscape of RNA metabolism and underpins control mediated by small regulatory RNAs in diverse bacterial species. We explored the enzyme's hydrolytic mechanism, allosteric activation, and interplay with partner proteins in the multicomponent RNA degradosome assembly of Escherichia coli. RNase E cleaves single-stranded RNA with preference to attack the phosphate located at the 5' nucleotide preceding uracil, and we corroborate key interactions that select that base. Unexpectedly, RNase E activity is impeded strongly when the recognized uracil is isomerized to 5-ribosyluracil (pseudouridine), from which we infer the detailed geometry of the hydrolytic attack process. Kinetics analyses support models for recognition of secondary structure in substrates by RNase E and for allosteric autoregulation. The catalytic power of the enzyme is boosted when it is assembled into the multienzyme RNA degradosome, most likely as a consequence of substrate capture and presentation. Our results rationalize the origins of substrate preferences of RNase E and illuminate its catalytic mechanism, supporting the roles of allosteric domain closure and cooperation with other components of the RNA degradosome complex.
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Affiliation(s)
- Md Saiful Islam
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Katarzyna J Bandyra
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Yanjie Chao
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
- The Center for Microbes, Development and Health (CMDH), Institut Pasteur of Shanghai, Chinese Academy of Sciences, Xuhui district, Shanghai, 200031, China
| | - Jörg Vogel
- RNA Biology Group, Institute of Molecular Infection Biology, University of Würzburg, D-97080 Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080 Würzburg, Germany
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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Post-Transcriptional Control in the Regulation of Polyhydroxyalkanoates Synthesis. Life (Basel) 2021; 11:life11080853. [PMID: 34440597 PMCID: PMC8401924 DOI: 10.3390/life11080853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/15/2021] [Accepted: 08/18/2021] [Indexed: 01/08/2023] Open
Abstract
The large production of non-degradable petrol-based plastics has become a major global issue due to its environmental pollution. Biopolymers produced by microorganisms such as polyhydroxyalkanoates (PHAs) are gaining potential as a sustainable alternative, but the high cost associated with their industrial production has been a limiting factor. Post-transcriptional regulation is a key step to control gene expression in changing environments and has been reported to play a major role in numerous cellular processes. However, limited reports are available concerning the regulation of PHA accumulation in bacteria, and many essential regulatory factors still need to be identified. Here, we review studies where the synthesis of PHA has been reported to be regulated at the post-transcriptional level, and we analyze the RNA-mediated networks involved. Finally, we discuss the forthcoming research on riboregulation, synthetic, and metabolic engineering which could lead to improved strategies for PHAs synthesis in industrial production, thereby reducing the costs currently associated with this procedure.
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