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de Araújo HL, Picinato BA, Lorenzetti APR, Muthunayake NS, Rathnayaka-Mudiyanselage IW, dos Santos NM, Schrader J, Koide T, Marques MV. The DEAD-box RNA helicase RhlB is required for efficient RNA processing at low temperature in Caulobacter. Microbiol Spectr 2023; 11:e0193423. [PMID: 37850787 PMCID: PMC10715135 DOI: 10.1128/spectrum.01934-23] [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: 05/11/2023] [Accepted: 09/12/2023] [Indexed: 10/19/2023] Open
Abstract
IMPORTANCE One of the most important control points in gene regulation is RNA stability, which determines the half-life of a transcript from its transcription until its degradation. Bacteria have evolved a sophisticated multi-enzymatic complex, the RNA degradosome, which is dedicated mostly to RNA turnover. The combined activity of RNase E and the other RNA degradosome enzymes provides an efficient pipeline for the complete degradation of RNAs. The DEAD-box RNA helicases are very often found in RNA degradosomes from phylogenetically distant bacteria, confirming their importance in unwinding structured RNA for subsequent degradation. This work showed that the absence of the RNA helicase RhlB in the free-living Alphaproteobacterium Caulobacter crescentus causes important changes in gene expression and cell physiology. These are probably due, at least in part, to inefficient RNA processing by the RNA degradosome, particularly at low-temperature conditions.
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Affiliation(s)
- Hugo L. de Araújo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Beatriz A. Picinato
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Alan P. R. Lorenzetti
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | | | - Naara M. dos Santos
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Jared Schrader
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | - Tie Koide
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marilis V. Marques
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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Structural Insights into the Dimeric Form of Bacillus subtilis RNase Y Using NMR and AlphaFold. Biomolecules 2022; 12:biom12121798. [PMID: 36551226 PMCID: PMC9775385 DOI: 10.3390/biom12121798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
RNase Y is a crucial component of genetic translation, acting as the key enzyme initiating mRNA decay in many Gram-positive bacteria. The N-terminal domain of Bacillus subtilis RNase Y (Nter-BsRNaseY) is thought to interact with various protein partners within a degradosome complex. Bioinformatics and biophysical analysis have previously shown that Nter-BsRNaseY, which is in equilibrium between a monomeric and a dimeric form, displays an elongated fold with a high content of α-helices. Using multidimensional heteronuclear NMR and AlphaFold models, here, we show that the Nter-BsRNaseY dimer is constituted of a long N-terminal parallel coiled-coil structure, linked by a turn to a C-terminal region composed of helices that display either a straight or bent conformation. The structural organization of the N-terminal domain is maintained within the AlphaFold model of the full-length RNase Y, with the turn allowing flexibility between the N- and C-terminal domains. The catalytic domain is globular, with two helices linking the KH and HD modules, followed by the C-terminal region. This latter region, with no function assigned up to now, is most likely involved in the dimerization of B. subtilis RNase Y together with the N-terminal coiled-coil structure.
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Polyribosome-Dependent Clustering of Membrane-Anchored RNA Degradosomes To Form Sites of mRNA Degradation in Escherichia coli. mBio 2021; 12:e0193221. [PMID: 34488454 PMCID: PMC8546579 DOI: 10.1128/mbio.01932-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The essential endoribonuclease RNase E, which is a component of the Escherichia coli multienzyme RNA degradosome, has a global role in RNA processing and degradation. RNase E localizes to the inner cytoplasmic membrane in small, short-lived clusters (puncta). Rifampin, which arrests transcription, inhibits RNase E clustering and increases its rate of diffusion. Here, we show that inhibition of clustering is due to the arrest of transcription using a rifampin-resistant control strain. Two components of the RNA degradosome, the 3′ exoribonuclease polynucleotide phosphorylase (PNPase) and the DEAD box RNA helicase RhlB, colocalize with RNase E in puncta. Clustering of PNPase and RhlB is inhibited by rifampin, and their diffusion rates increase, as evidenced by in vivo photobleaching measurements. Results with rifampin treatment reported here show that RNA degradosome diffusion is constrained by interaction with RNA substrate. Kasugamycin, which arrests translation initiation, inhibits formation of puncta and increases RNA degradosome diffusion rates. Since kasugamycin treatment results in continued synthesis and turnover of ribosome-free mRNA but inhibits polyribosome formation, RNA degradosome clustering is therefore polyribosome dependent. Chloramphenicol, which arrests translation elongation, results in formation of large clusters (foci) of RNA degradosomes that are distinct from puncta. Since chloramphenicol-treated ribosomes are stable, the formation of RNA degradosome foci could be part of a stress response that protects inactive polyribosomes from degradation. Our results strongly suggest that puncta are sites where translationally active polyribosomes are captured by membrane-associated RNA degradosomes. These sites could be part of a scanning process that is an initial step in mRNA degradation.
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Jaso-Vera ME, Domínguez-Malfavón L, Curiel-Quesada E, García-Mena J. Dynamics of the canonical RNA degradosome components during glucose stress. Biochimie 2021; 187:67-74. [PMID: 34022290 DOI: 10.1016/j.biochi.2021.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/21/2021] [Accepted: 05/12/2021] [Indexed: 11/19/2022]
Abstract
The RNA Degradosome (RNAD) is a multi-enzyme complex, which performs important functions in post-transcriptional regulation in Escherichia coli with the assistance of regulatory sRNAs and the RNA chaperone Hfq. Although the interaction of the canonical RNAD components with RNase E has been extensively studied, the dynamic nature of the interactions in vivo remains largely unknown. In this work, we explored the rearrangements upon glucose stress using fluorescence energy transfer (hetero-FRET). Results revealed differences in the proximity of the canonical components with 1% (55.5 mM) glucose concentration, with the helicase RhlB and the glycolytic enzyme Enolase exhibiting the largest changes to the C-terminus of RNase E, followed by PNPase. We quantified ptsG mRNA decay and SgrS sRNA synthesis as they mediate bacterial adaptation to glucose stress conditions. We propose that once the mRNA degradation is completed, the RhlB, Enolase and PNPase decrease their proximity to the C-terminus of RNase E. Based on the results, we present a model where the canonical components of the RNAD coalesce when the bacteria is under glucose-6-phosphate stress and associate it with RNA decay. Our results demonstrate that FRET is a helpful tool to study conformational rearrangements in enzymatic complexes in bacteria in vivo.
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Affiliation(s)
- Marcos Emmanuel Jaso-Vera
- Departamento de Genética y Biología Molecular, Cinvestav, Unidad Zacatenco, Ciudad de México, 07360, Mexico
| | - Lilianha Domínguez-Malfavón
- Department of Biotechnology, Universidad Autónoma Metropolitana (Unidad Iztapalapa), Ciudad de México, 09340, Mexico
| | - Everardo Curiel-Quesada
- Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional (ENCB-IPN), Ciudad de México, 11340, Mexico
| | - Jaime García-Mena
- Departamento de Genética y Biología Molecular, Cinvestav, Unidad Zacatenco, Ciudad de México, 07360, Mexico.
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Ingle S, Chhabra S, Laspina D, Salvo E, Liu B, Bechhofer DH. Polynucleotide phosphorylase and RNA helicase CshA cooperate in Bacillus subtilis mRNA decay. RNA Biol 2020; 18:1692-1701. [PMID: 33323028 DOI: 10.1080/15476286.2020.1864183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Polynucleotide phosphorylase (PNPase), a 3' exoribonuclease that degrades RNA in the 3'-to-5' direction, is the major mRNA decay activity in Bacillus subtilis. PNPase is known to be inhibited in vitro by strong RNA secondary structure, and rapid mRNA turnover in vivo is thought to require an RNA helicase activity working in conjunction with PNPase. The most abundant RNA helicase in B. subtilis is CshA. We found for three small, monocistronic mRNAs that, for some RNA sequences, PNPase processivity was unimpeded even without CshA, whereas others required CshA for efficient degradation. A novel colour screen for decay of mRNA in B. subtilis was created, using mRNA encoded by the slrA gene, which is degraded from its 3' end by PNPase. A significant correlation between the predicted strength of a stem-loop structure, located in the body of the message, and PNPase processivity was observed. Northern blot analysis confirmed that PNPase processivity was greatly hindered by the internal RNA structure, and even more so in the absence of CshA. Three other B. subtilis RNA helicases did not appear to be involved in mRNA decay during vegetative growth. The results confirm the hypothesis that efficient 3' exonucleolytic decay of B. subtilis RNA depends on the combined activity of PNPase and CshA.
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Affiliation(s)
- Shakti Ingle
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
| | - Shivani Chhabra
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
| | - Denise Laspina
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
| | - Elizabeth Salvo
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
| | - Bo Liu
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
| | - David H Bechhofer
- Icahn School of Medicine at Mount Sinai, Department of Pharmacological Sciences, New York, NY, USA
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Mu R, Shinde P, Zou Z, Kreth J, Merritt J. Examining the Protein Interactome and Subcellular Localization of RNase J2 Complexes in Streptococcus mutans. Front Microbiol 2019; 10:2150. [PMID: 31620106 PMCID: PMC6759994 DOI: 10.3389/fmicb.2019.02150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/02/2019] [Indexed: 12/18/2022] Open
Abstract
Regulated RNA turnover is vital for the control of gene expression in all cellular life. In Escherichia coli, this process is largely controlled by a stable degradosome complex containing RNase E and a variety of additional enzymes. In the Firmicutes phylum, species lack RNase E and often encode the paralogous enzymes RNase J1 and RNase J2. Unlike RNase J1, surprisingly little is known about the regulatory function and protein interactions of RNase J2, despite being a central pleiotropic regulator for the streptococci and other closely related organisms. Using crosslink coimmunoprecipitation in Streptococcus mutans, we have identified the major proteins found within RNase J2 protein complexes located in the cytoplasm and at the cell membrane. In both subcellular fractions, RNase J2 exhibited the most robust interactions with RNase J1, while additional transient and/or weaker "degradosome-like" interactions were also detected. In addition, RNase J2 exhibits multiple novel interactions that have not been previously reported for any RNase J proteins, some of which were highly biased for either the cytoplasmic or membrane fractions. We also determined that the RNase J2 C-terminal domain (CTD) encodes a structure that is likely conserved among RNase J enzymes and may have an analogous function to the C-terminal portion of RNase E. While we did observe a number of parallels between the RNase J2 interactome and the E. coli degradosome paradigm, our results suggest that S. mutans degradosomes are either unlikely to exist or are quite distinct from those of E. coli.
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Affiliation(s)
- Rong Mu
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
| | - Pushkar Shinde
- Emory College of Arts and Sciences, Atlanta, GA, United States
| | - Zhengzhong Zou
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States
| | - Jens Kreth
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States.,Department of Molecular Microbiology and Immunology, School of Medicine, Oregon Health and Science University, Portland, OR, United States
| | - Justin Merritt
- Department of Restorative Dentistry, School of Dentistry, Oregon Health and Science University, Portland, OR, United States.,Department of Molecular Microbiology and Immunology, School of Medicine, Oregon Health and Science University, Portland, OR, United States
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3'-UTR engineering to improve soluble expression and fine-tuning of activity of cascade enzymes in Escherichia coli. Sci Rep 2016; 6:29406. [PMID: 27406241 PMCID: PMC4942690 DOI: 10.1038/srep29406] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/20/2016] [Indexed: 02/06/2023] Open
Abstract
3′-Untranslated region (3′UTR) engineering was investigated to improve solubility of heterologous proteins (e.g., Baeyer-Villiger monooxygenases (BVMOs)) in Escherichia coli. Insertion of gene fragments containing putative RNase E recognition sites into the 3′UTR of the BVMO genes led to the reduction of mRNA levels in E. coli. Importantly, the amounts of soluble BVMOs were remarkably enhanced resulting in a proportional increase of in vivo catalytic activities. Notably, this increase in biocatalytic activity correlated to the number of putative RNase E endonucleolytic cleavage sites in the 3′UTR. For instance, the biotransformation activity of the BVMO BmoF1 (from Pseudomonas fluorescens DSM50106) in E. coli was linear to the number of RNase E cleavage sites in the 3′UTR. In summary, 3′UTR engineering can be used to improve the soluble expression of heterologous enzymes, thereby fine-tuning the enzyme activity in microbial cells.
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RNA Helicase Important for Listeria monocytogenes Hemolytic Activity and Virulence Factor Expression. Infect Immun 2015; 84:67-76. [PMID: 26483402 DOI: 10.1128/iai.00849-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/10/2015] [Indexed: 01/12/2023] Open
Abstract
RNA helicases have been shown to be important for the function of RNA molecules at several levels, although their putative involvement in microbial pathogenesis has remained elusive. We have previously shown that Listeria monocytogenes DExD-box RNA helicases are important for bacterial growth, motility, ribosomal maturation, and rRNA processing. We assessed the importance of the RNA helicase Lmo0866 (here named CshA) for expression of virulence traits. We observed a reduction in hemolytic activity in a strain lacking CshA compared to the wild type. This phenomenon was less evident in strains lacking other RNA helicases. The reduced hemolysis was accompanied by lower expression of major listerial virulence factors in the ΔcshA strain, mainly listeriolysin O, but also to some degree the actin polymerizing factor ActA. Reduced expression of these virulence factors in the strain lacking CshA did not, however, correlate with a decreased level of the virulence regulator PrfA. When combining the ΔcshA knockout with a mutation creating a constitutively active PrfA protein (PrfA*), the effect of the ΔcshA knockout on LLO expression was negated. These data suggest a role for the RNA helicase CshA in posttranslational activation of PrfA. Surprisingly, although the expression of several virulence factors was reduced, the ΔcshA strain did not demonstrate any reduced ability to infect nonphagocytic cells compared to the wild-type strain.
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CsrA Participates in a PNPase Autoregulatory Mechanism by Selectively Repressing Translation of pnp Transcripts That Have Been Previously Processed by RNase III and PNPase. J Bacteriol 2015; 197:3751-9. [PMID: 26438818 DOI: 10.1128/jb.00721-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 09/28/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Csr is a conserved global regulatory system that represses or activates gene expression posttranscriptionally. CsrA of Escherichia coli is a homodimeric RNA binding protein that regulates transcription elongation, translation initiation, and mRNA stability by binding to the 5' untranslated leader or initial coding sequence of target transcripts. pnp mRNA, encoding the 3' to 5' exoribonuclease polynucleotide phosphorylase (PNPase), was previously identified as a CsrA target by transcriptome sequencing (RNA-seq). Previous studies also showed that RNase III and PNPase participate in a pnp autoregulatory mechanism in which RNase III cleavage of the untranslated leader, followed by PNPase degradation of the resulting 5' fragment, leads to pnp repression by an undefined translational repression mechanism. Here we demonstrate that CsrA binds to two sites in pnp leader RNA but only after the transcript is fully processed by RNase III and PNPase. In the absence of processing, both of the binding sites are sequestered in an RNA secondary structure, which prevents CsrA binding. The CsrA dimer bridges the upstream high-affinity site to the downstream site that overlaps the pnp Shine-Dalgarno sequence such that bound CsrA causes strong repression of pnp translation. CsrA-mediated translational repression also leads to a small increase in the pnp mRNA decay rate. Although CsrA has been shown to regulate translation and mRNA stability of numerous genes in a variety of organisms, this is the first example in which prior mRNA processing is required for CsrA-mediated regulation. IMPORTANCE CsrA protein represses translation of numerous mRNA targets, typically by binding to multiple sites in the untranslated leader region preceding the coding sequence. We found that CsrA represses translation of pnp by binding to two sites in the pnp leader transcript but only after it is processed by RNase III and PNPase. Processing by these two ribonucleases alters the mRNA secondary structure such that it becomes accessible to the ribosome for translation as well as to CsrA. As one of the CsrA binding sites overlaps the pnp ribosome binding site, bound CsrA prevents ribosome binding. This is the first example in which regulation by CsrA requires prior mRNA processing and should link pnp expression to conditions affecting CsrA activity.
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Aït-Bara S, Carpousis AJ. RNA degradosomes in bacteria and chloroplasts: classification, distribution and evolution of RNase E homologs. Mol Microbiol 2015; 97:1021-135. [PMID: 26096689 DOI: 10.1111/mmi.13095] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 11/29/2022]
Abstract
Ribonuclease E (RNase E) of Escherichia coli, which is the founding member of a widespread family of proteins in bacteria and chloroplasts, is a fascinating enzyme that still has not revealed all its secrets. RNase E is an essential single-strand specific endoribonuclease that is involved in the processing and degradation of nearly every transcript in E. coli. A striking enzymatic property is a preference for substrates with a 5' monophosphate end although recent work explains how RNase E can overcome the protection afforded by the 5' triphosphate end of a primary transcript. Other features of E. coli RNase E include its interaction with enzymes involved in RNA degradation to form the multienzyme RNA degradosome and its localization to the inner cytoplasmic membrane. The N-terminal catalytic core of the RNase E protomer associates to form a tetrameric holoenzyme. Each RNase E protomer has a large C-terminal intrinsically disordered (ID) noncatalytic region that contains sites for interactions with protein components of the RNA degradosome as well as RNA and phospholipid bilayers. In this review, RNase E homologs have been classified into five types based on their primary structure. A recent analysis has shown that type I RNase E in the γ-proteobacteria forms an orthologous group of proteins that has been inherited vertically. The RNase E catalytic core and a large ID noncatalytic region containing an RNA binding motif and a membrane targeting sequence are universally conserved features of these orthologs. Although the ID noncatalytic region has low composition and sequence complexity, it is possible to map microdomains, which are short linear motifs that are sites of interaction with protein and other ligands. Throughout bacteria, the composition of the multienzyme RNA degradosome varies with species, but interactions with exoribonucleases (PNPase, RNase R), glycolytic enzymes (enolase, aconitase) and RNA helicases (DEAD-box proteins, Rho) are common. Plasticity in RNA degradosome composition is due to rapid evolution of RNase E microdomains. Characterization of the RNase E-PNPase interaction in α-proteobacteria, γ-proteobacteria and cyanobacteria suggests that it arose independently several times during evolution, thus conferring an advantage in control and coordination of RNA processing and degradation.
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Affiliation(s)
- Soraya Aït-Bara
- Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte, Institut, National de la Santé et de la Recherche Médicale & Université d'Auvergne, Clermont-Ferrand, 63001, France
| | - Agamemnon J Carpousis
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR 5100, Centre National de la Recherche Scientifique et Université de Toulouse 3, Toulouse, 31062, France
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Rapid degradation of Hfq-free RyhB in Yersinia pestis by PNPase independent of putative ribonucleolytic complexes. BIOMED RESEARCH INTERNATIONAL 2014; 2014:798918. [PMID: 24818153 PMCID: PMC4003864 DOI: 10.1155/2014/798918] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 03/10/2014] [Accepted: 03/15/2014] [Indexed: 11/17/2022]
Abstract
The RNA chaperone Hfq in bacteria stabilizes sRNAs by protecting them from the attack of ribonucleases. Upon release from Hfq, sRNAs are preferably degraded by PNPase. PNPase usually forms multienzyme ribonucleolytic complexes with endoribonuclease E and/or RNA helicase RhlB to facilitate the degradation of the structured RNA. However, whether PNPase activity on Hfq-free sRNAs is associated with the assembly of RNase E or RhlB has yet to be determined. Here we examined the roles of the main endoribonucleases, exoribonucleases, and ancillary RNA-modifying enzymes in the degradation of Y. pestis RyhB in the absence of Hfq. Expectedly, the transcript levels of both RyhB1 and RyhB2 increase only after inactivating PNPase, which confirms the importance of PNPase in sRNA degradation. By contrast, the signal of RyhB becomes barely perceptible after inactivating of RNase III, which may be explained by the increase in PNPase levels resulting from the exemption of pnp mRNA from RNase III processing. No significant changes are observed in RyhB stability after deletion of either the PNPase-binding domain of RNase E or rhlB. Therefore, PNPase acts as a major enzyme of RyhB degradation independent of PNPase-containing RNase E and RhlB assembly in the absence of Hfq.
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Göpel Y, Khan MA, Görke B. Ménage à trois: post-transcriptional control of the key enzyme for cell envelope synthesis by a base-pairing small RNA, an RNase adaptor protein, and a small RNA mimic. RNA Biol 2014; 11:433-42. [PMID: 24667238 PMCID: PMC4152352 DOI: 10.4161/rna.28301] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In Escherichia coli, small RNAs GlmY and GlmZ feedback control synthesis of glucosamine-6-phosphate (GlcN6P) synthase GlmS, a key enzyme required for synthesis of the cell envelope. Both small RNAs are highly similar, but only GlmZ is able to activate the glmS mRNA by base-pairing. Abundance of GlmZ is controlled at the level of decay by RNase adaptor protein RapZ. RapZ binds and targets GlmZ to degradation by RNase E via protein–protein interaction. GlmY activates glmS indirectly by protecting GlmZ from degradation. Upon GlcN6P depletion, GlmY accumulates and sequesters RapZ in an RNA mimicry mechanism, thus acting as an anti-adaptor. As a result, this regulatory circuit adjusts synthesis of GlmS to the level of its enzymatic product, thereby mediating GlcN6P homeostasis. The interplay of RNase adaptor proteins and anti-adaptors provides an elegant means how globally acting RNases can be re-programmed to cleave a specific transcript in response to a cognate stimulus.
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Affiliation(s)
- Yvonne Göpel
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
| | - Muna A Khan
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
| | - Boris Görke
- Max F. Perutz Laboratories; Department of Microbiology; Immunobiology and Genetics; Center of Molecular Biology; University of Vienna; Vienna, Austria
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