1
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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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2
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Collins MJ, Tomares DT, Nandana V, Schrader JM, Childers WS. RNase E biomolecular condensates stimulate PNPase activity. Sci Rep 2023; 13:12937. [PMID: 37558691 PMCID: PMC10412687 DOI: 10.1038/s41598-023-39565-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 07/27/2023] [Indexed: 08/11/2023] Open
Abstract
Bacterial Ribonucleoprotein bodies (BR-bodies) play an essential role in organizing RNA degradation via phase separation in the cytoplasm of bacteria. BR-bodies mediate multi-step mRNA decay through the concerted activity of the endoribonuclease RNase E coupled with the 3'-5' exoribonuclease Polynucleotide Phosphorylase (PNPase). In vivo, studies indicated that the loss of PNPase recruitment into BR-bodies led to a significant build-up of RNA decay intermediates in Caulobacter crescentus. However, it remained unclear whether this is due to a lack of colocalized PNPase and RNase E within BR-bodies or whether PNPase's activity is stimulated within the BR-body. We reconstituted RNase E's C-terminal domain with PNPase towards a minimal BR-body in vitro to distinguish these possibilities. We found that PNPase's catalytic activity is accelerated when colocalized within the RNase E biomolecular condensates, partly due to scaffolding and mass action effects. In contrast, disruption of the RNase E-PNPase protein-protein interaction led to a loss of PNPase recruitment into the RNase E condensates and a loss of ribonuclease rate enhancement. We also found that RNase E's unique biomolecular condensate environment tuned PNPase's substrate specificity for poly(A) over poly(U). Intriguingly, a critical PNPase reactant, phosphate, reduces RNase E phase separation both in vitro and in vivo. This regulatory feedback ensures that under limited phosphate resources, PNPase activity is enhanced by recruitment into RNase E's biomolecular condensates.
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Affiliation(s)
- Michael J Collins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, 15260, USA
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, 15260, USA
| | - Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, 15260, USA.
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3
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Jain C. Suppression of multiple phenotypic and RNA processing defects by over-expression of Oligoribonuclease in Escherichia coli. J Biol Chem 2023; 299:104567. [PMID: 36870683 PMCID: PMC10124918 DOI: 10.1016/j.jbc.2023.104567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 02/17/2023] [Accepted: 02/18/2023] [Indexed: 03/06/2023] Open
Abstract
Oligoribonuclease (Orn) is an essential Ribonuclease (RNase) from Escherichia coli (E. coli), which plays a critical role in the conversion of short RNA molecules (NanoRNAs) to mononucleotides. Although no additional functions have been ascribed to Orn since its discovery nearly 50 years ago, it was observed in this study that the growth defects caused by a lack of two other RNases that do not digest NanoRNAs, PNPase and RNase PH, could be suppressed by Orn over-expression. Further analyses showed that Orn over-expression can alleviate the growth defects caused by an absence of other RNases even when its expression was increased by a small degree, and it can carry out molecular reactions that are normally performed by RNase T and RNase PH. In addition, biochemical assays revealed that Orn can fully digest single stranded RNAs within a variety of structural contexts. These studies provide new insights into Orn function and its ability to participate in multiple aspects of E. coli RNA metabolism.
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Affiliation(s)
- Chaitanya Jain
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, Florida, USA.
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4
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Francis N, Behera MR, Natarajan K, Laishram RS. Tyrosine phosphorylation controlled poly(A) polymerase I activity regulates general stress response in bacteria. Life Sci Alliance 2023; 6:6/3/e202101148. [PMID: 36535710 PMCID: PMC9764084 DOI: 10.26508/lsa.202101148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
RNA 3'-end polyadenylation that marks transcripts for degradation is implicated in general stress response in Escherichia coli Yet, the mechanism and regulation of poly(A) polymerase I (PAPI) in stress response are obscure. We show that pcnB (that encodes PAPI)-null mutation widely stabilises stress response mRNAs and imparts cellular tolerance to multiple stresses, whereas PAPI ectopic expression renders cells stress-sensitive. We demonstrate that there is a substantial loss of PAPI activity on stress exposure that functionally phenocopies pcnB-null mutation stabilising target mRNAs. We identify PAPI tyrosine phosphorylation at the 202 residue (Y202) that is enormously enhanced on stress exposure. This phosphorylation inhibits PAPI polyadenylation activity under stress. Consequentially, PAPI phosphodeficient mutation (tyrosine 202 to phenylalanine, Y202F) fails to stimulate mRNA expression rendering cells stress-sensitive. Bacterial tyrosine kinase Wzc phosphorylates PAPI-Y202 residue, and that wzc-null mutation renders cells stress-sensitive. Accordingly, wzc-null mutation has no effect on stress sensitivity in the presence of pcnB-null or pcnB-Y202F mutation. We also establish that PAPI phosphorylation-dependent stress tolerance mechanism is distinct and operates downstream of the primary stress regulator RpoS.
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Affiliation(s)
- Nimmy Francis
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
| | - Malaya R Behera
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India.,Regional Centre for Biotechnology, Faridabad, India
| | - Kathiresan Natarajan
- Transdisciplinary Biology Program, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
| | - Rakesh S Laishram
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
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5
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Improving glycine utilization in Escherichia coli. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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6
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Abstract
Dickeya dadantii is a phytopathogenic bacterium that causes soft rot in a wide range of plant hosts worldwide and a model organism for studying virulence gene regulation. The present study provides a comprehensive and annotated transcriptomic map of D. dadantii obtained by a computational method combining five independent transcriptomic data sets: (i) paired-end RNA sequencing (RNA-seq) data for a precise reconstruction of the RNA landscape; (ii) DNA microarray data providing transcriptional responses to a broad variety of environmental conditions; (iii) long-read Nanopore native RNA-seq data for isoform-level transcriptome validation and determination of transcription termination sites; (iv) differential RNA sequencing (dRNA-seq) data for the precise mapping of transcription start sites; (v) in planta DNA microarray data for a comparison of gene expression profiles between in vitro experiments and the early stages of plant infection. Our results show that transcription units sometimes coincide with predicted operons but are generally longer, most of them comprising internal promoters and terminators that generate alternative transcripts of variable gene composition. We characterize the occurrence of transcriptional read-through at terminators, which might play a basal regulation role and explain the extent of transcription beyond the scale of operons. We finally highlight the presence of noncontiguous operons and excludons in the D. dadantii genome, novel genomic arrangements that might contribute to the basal coordination of transcription. The highlighted transcriptional organization may allow D. dadantii to finely adjust its gene expression program for a rapid adaptation to fast-changing environments.
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7
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Abstract
Detailed studies of the Gram-negative model bacterium, Escherichia coli, have demonstrated that post-transcriptional events exert important and possibly greater control over gene regulation than transcription initiation or effective translation. Thus, over the past 30 years, considerable effort has been invested in understanding the pathways of mRNA turnover in E. coli. Although it is assumed that most of the ribonucleases and accessory proteins involved in mRNA decay have been identified, our understanding of the regulation of mRNA decay is still incomplete. Furthermore, the vast majority of the studies on mRNA decay have been conducted on exponentially growing cells. Thus, the mechanism of mRNA decay as currently outlined may not accurately reflect what happens when cells find themselves under a variety of stress conditions, such as, nutrient starvation, changes in pH and temperature, as well as a host of others. While the cellular machinery for degradation is relatively constant over a wide range of conditions, intracellular levels of specific ribonucleases can vary depending on the growth conditions. Substrate competition will also modulate ribonucleolytic activity. Post-transcriptional modifications of transcripts by polyadenylating enzymes may favor a specific ribonuclease activity. Interactions with small regulatory RNAs and RNA binding proteins add additional complexities to mRNA functionality and stability. Since many of the ribonucleases are found at the inner membrane, the physical location of a transcript may help determine its half-life. Here we discuss the properties and role of the enzymes involved in mRNA decay as well as the multiple factors that may affect mRNA decay under various in vivo conditions.
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Affiliation(s)
| | - Sidney R. Kushner
- Department of Genetics, University of Georgia, Athens GA 30602,Department of Microbiology, University of Georgia, Athens GA 30602,To whom correspondence should be addressed:
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8
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Machado de Amorim A, Chakrabarti S. Assembly of multicomponent machines in RNA metabolism: A common theme in mRNA decay pathways. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1684. [PMID: 34351053 DOI: 10.1002/wrna.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Multicomponent protein-RNA complexes comprising a ribonuclease and partner RNA helicase facilitate the turnover of mRNA in all domains of life. While these higher-order complexes provide an effective means of physically and functionally coupling the processes of RNA remodeling and decay, most ribonucleases and RNA helicases do not exhibit sequence specificity in RNA binding. This raises the question as to how these assemblies select substrates for processing and how the activities are orchestrated at the precise moment to ensure efficient decay. The answers to these apparent puzzles lie in the auxiliary components of the assemblies that might relay decay-triggering signals. Given their function within the assemblies, these components may be viewed as "sensors." The functions and mechanisms of action of the sensor components in various degradation complexes in bacteria and eukaryotes are highlighted here to discuss their roles in RNA decay processes. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
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9
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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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10
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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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11
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Muthunayake NS, Tomares DT, Childers WS, Schrader JM. Phase-separated bacterial ribonucleoprotein bodies organize mRNA decay. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1599. [PMID: 32445438 PMCID: PMC7554086 DOI: 10.1002/wrna.1599] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 01/12/2023]
Abstract
In bacteria, mRNA decay is controlled by megadalton scale macromolecular assemblies called, "RNA degradosomes," composed of nucleases and other RNA decay associated proteins. Recent advances in bacterial cell biology have shown that RNA degradosomes can assemble into phase-separated structures, termed bacterial ribonucleoprotein bodies (BR-bodies), with many analogous properties to eukaryotic processing bodies and stress granules. This review will highlight the functional role that BR-bodies play in the mRNA decay process through its organization into a membraneless organelle in the bacterial cytoplasm. This review will also highlight the phylogenetic distribution of BR-bodies across bacterial species, which suggests that these phase-separated structures are broadly distributed across bacteria, and in evolutionarily related mitochondria and chloroplasts. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
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12
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Li J, Hou Y, Gu X, Yue L, Guo L, Li D, Dong X. A newly identified duplex RNA unwinding activity of archaeal RNase J depends on processive exoribonucleolysis coupled steric occlusion by its structural archaeal loops. RNA Biol 2020; 17:1480-1491. [PMID: 32552320 DOI: 10.1080/15476286.2020.1777379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
RNase J is a prokaryotic 5'-3' exo/endoribonuclease that functions in mRNA decay and rRNA maturation. Here, we report a novel duplex unwinding activity of mpy-RNase J, an archaeal RNase J from Methanolobus psychrophilus, which enables it to degrade duplex RNAs with hairpins up to 40 bp when linking a 5' single-stranded overhangs of ≥ 7 nt, corresponding to the RNA channel length. A 6-nt RNA-mpy-RNase J-S247A structure reveals the RNA-interacting residues and a steric barrier at the RNA channel entrance comprising two archaeal loops and two helices. Mutagenesis of the residues key to either exoribonucleolysis or RNA translocation diminished the duplex unwinding activity. Substitution of the residues in the steric barrier yielded stalled degradation intermediates at the duplex RNA regions. Thus, an exoribonucleolysis-driven and steric occlusion-based duplex unwinding mechanism was identified. The duplex unwinding activity confers mpy-RNase J the capability of degrading highly structured RNAs, including the bacterial REP RNA, and archaeal mRNAs, rRNAs, tRNAs, SRPs, RNase P and CD-box RNAs, providing an indicative of the potential key roles of mpy-RNase J in pleiotropic RNA metabolisms. Hydrolysis-coupled duplex unwinding activity was also detected in a bacterial RNase J, which may use a shared but slightly different unwinding mechanism from archaeal RNase Js, indicating that duplex unwinding is a common property of the prokaryotic RNase Js.
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Affiliation(s)
- Jie Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing, PR China.,Colleges of Life Sciences, University of Chinese Academy of Sciences , Beijing, China
| | - Yanjie Hou
- Institute of Biophysics, Chinese Academy of Sciences , Beijing, PR China
| | - Xien Gu
- School of Basic Medical Sciences, Hubei University of Medicine , Shiyan, China
| | - Lei Yue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing, PR China.,Colleges of Life Sciences, University of Chinese Academy of Sciences , Beijing, China
| | - Lu Guo
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing, PR China
| | - Defeng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing, PR China.,Colleges of Life Sciences, University of Chinese Academy of Sciences , Beijing, China
| | - Xiuzhu Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences , Beijing, PR China.,Colleges of Life Sciences, University of Chinese Academy of Sciences , Beijing, China
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13
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Al-Husini N, Tomares DT, Pfaffenberger ZJ, Muthunayake NS, Samad MA, Zuo T, Bitar O, Aretakis JR, Bharmal MHM, Gega A, Biteen JS, Childers WS, Schrader JM. BR-Bodies Provide Selectively Permeable Condensates that Stimulate mRNA Decay and Prevent Release of Decay Intermediates. Mol Cell 2020; 78:670-682.e8. [PMID: 32343944 DOI: 10.1016/j.molcel.2020.04.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/16/2019] [Accepted: 03/30/2020] [Indexed: 12/22/2022]
Abstract
Biomolecular condensates play a key role in organizing RNAs and proteins into membraneless organelles. Bacterial RNP-bodies (BR-bodies) are a biomolecular condensate containing the RNA degradosome mRNA decay machinery, but the biochemical function of such organization remains poorly defined. Here, we define the RNA substrates of BR-bodies through enrichment of the bodies followed by RNA sequencing (RNA-seq). We find that long, poorly translated mRNAs, small RNAs, and antisense RNAs are the main substrates, while rRNA, tRNA, and other conserved non-coding RNAs (ncRNAs) are excluded from these bodies. BR-bodies stimulate the mRNA decay rate of enriched mRNAs, helping to reshape the cellular mRNA pool. We also observe that BR-body formation promotes complete mRNA decay, avoiding the buildup of toxic endo-cleaved mRNA decay intermediates. The combined selective permeability of BR-bodies for both enzymes and substrates together with the stimulation of the sub-steps of mRNA decay provide an effective organization strategy for bacterial mRNA decay.
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | | | - Mohammad A Samad
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Tiancheng Zuo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Obaidah Bitar
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - James R Aretakis
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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14
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Viegas SC, Matos RG, Arraiano CM. The Bacterial Counterparts of the Eukaryotic Exosome: An Evolutionary Perspective. Methods Mol Biol 2020; 2062:37-46. [PMID: 31768970 DOI: 10.1007/978-1-4939-9822-7_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
There are striking similarities between the processes of RNA degradation in bacteria and eukaryotes, which rely on the same basic set of enzymatic activities. In particular, enzymes that catalyze 3'→5' RNA decay share evolutionary relationships across the three domains of life. Over the years, a large body of biochemical and structural data has been generated that elucidated the mechanism of action of these enzymes. In this overview, to trace the evolutionary origins of the multisubunit RNA exosome complex, we compare the structural and functional characteristics of the eukaryotic and prokaryotic exoribonucleolytic activities.
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Affiliation(s)
- Sandra C Viegas
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal.
| | - Rute G Matos
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Oeiras, Portugal.
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15
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Baek YM, Jang KJ, Lee H, Yoon S, Baek A, Lee K, Kim DE. The bacterial endoribonuclease RNase E can cleave RNA in the absence of the RNA chaperone Hfq. J Biol Chem 2019; 294:16465-16478. [PMID: 31540970 DOI: 10.1074/jbc.ra119.010105] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/18/2019] [Indexed: 11/06/2022] Open
Abstract
RNase E is a component of the RNA degradosome complex and plays a key role in RNA degradation and maturation in Escherichia coli RNase E-mediated target RNA degradation typically involves the RNA chaperone Hfq and requires small guide RNAs (sRNAs) acting as a seed by binding to short (7-12-bp) complementary regions in target RNA sequences. Here, using recombinantly expressed and purified proteins, site-directed mutagenesis, and RNA cleavage and protein cross-linking assays, we investigated Hfq-independent RNA decay by RNase E. Exploring its RNA substrate preferences in the absence of Hfq, we observed that RNase E preferentially cleaves AU-rich sites of single-stranded regions of RNA substrates that are annealed to an sRNA that contains a monophosphate at its 5'-end. We further found that the quaternary structure of RNase E is also important for complete, Hfq-independent cleavage at sites both proximal and distal to the sRNA-binding site within target RNAs containing monophosphorylated 5'-ends. Of note, genetic RNase E variants with unstable quaternary structure exhibited decreased catalytic activity. In summary, our results show that RNase E can degrade its target RNAs in the absence of the RNA chaperone Hfq. We conclude that RNase E-mediated, Hfq-independent RNA decay in E. coli requires a cognate sRNA sequence for annealing to the target RNA, a 5'-monophosphate at the RNA 5'-end, and a stable RNase E quaternary structure.
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Affiliation(s)
- Yu Mi Baek
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Kyoung-Jin Jang
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Hyobeen Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Soojin Yoon
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Ahruem Baek
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
| | - Kangseok Lee
- Department of Life Science, Chung-Ang University, Seoul 06974, Korea
| | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea
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16
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Abstract
RNA-binding proteins (RBPs) are central to most if not all cellular processes, dictating the fate of virtually all RNA molecules in the cell. Starting with pioneering work on ribosomal proteins, studies of bacterial RBPs have paved the way for molecular studies of RNA-protein interactions. Work over the years has identified major RBPs that act on cellular transcripts at the various stages of bacterial gene expression and that enable their integration into post-transcriptional networks that also comprise small non-coding RNAs. Bacterial RBP research has now entered a new era in which RNA sequencing-based methods permit mapping of RBP activity in a truly global manner in vivo. Moreover, the soaring interest in understudied members of host-associated microbiota and environmental communities is likely to unveil new RBPs and to greatly expand our knowledge of RNA-protein interactions in bacteria.
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Affiliation(s)
- Erik Holmqvist
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany. .,Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
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17
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Abstract
RNA molecules have the tendency to fold into complex structures or to associate with complementary RNAs that exoribonucleases have difficulties processing or degrading. Therefore, degradosomes in bacteria and organelles as well as exosomes in eukaryotes have teamed-up with RNA helicases. Whereas bacterial degradosomes are associated with RNA helicases from the DEAD-box family, the exosomes and mitochondrial degradosome use the help of Ski2-like and Suv3 RNA helicases.
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18
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Chu LY, Hsieh TJ, Golzarroshan B, Chen YP, Agrawal S, Yuan HS. Structural insights into RNA unwinding and degradation by RNase R. Nucleic Acids Res 2017; 45:12015-12024. [PMID: 29036353 PMCID: PMC5714204 DOI: 10.1093/nar/gkx880] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/25/2017] [Indexed: 11/13/2022] Open
Abstract
RNase R is a conserved exoribonuclease in the RNase II family that primarily participates in RNA decay in all kingdoms of life. RNase R degrades duplex RNA with a 3′ overhang, suggesting that it has RNA unwinding activity in addition to its 3′-to-5′ exoribonuclease activity. However, how RNase R coordinates RNA binding with unwinding to degrade RNA remains elusive. Here, we report the crystal structure of a truncated form of Escherichia coli RNase R (residues 87–725) at a resolution of 1.85 Å. Structural comparisons with other RNase II family proteins reveal two open RNA-binding channels in RNase R and suggest a tri-helix ‘wedge’ region in the RNB domain that may induce RNA unwinding. We constructed two tri-helix wedge mutants and they indeed lost their RNA unwinding but not RNA binding or degrading activities. Our results suggest that the duplex RNA with an overhang is bound in the two RNA-binding channels in RNase R. The 3′ overhang is threaded into the active site and the duplex RNA is unwound upon reaching the wedge region during RNA degradation. Thus, RNase R is a proficient enzyme, capable of concurrently binding, unwinding and degrading structured RNA in a highly processive manner during RNA decay.
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Affiliation(s)
- Lee-Ya Chu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, Taiwan 30013, ROC
| | - Tung-Ju Hsieh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Bagher Golzarroshan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, Taiwan 30013, ROC
| | - Yi-Ping Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Sashank Agrawal
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Molecular and Cell Biology Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan 11490, ROC
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, ROC
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19
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Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus. J Bacteriol 2017; 199:JB.00135-17. [PMID: 28396352 PMCID: PMC5472812 DOI: 10.1128/jb.00135-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/03/2017] [Indexed: 01/08/2023] Open
Abstract
In diverse bacterial lineages, multienzyme assemblies have evolved that are central elements of RNA metabolism and RNA-mediated regulation. The aquatic Gram-negative bacterium Caulobacter crescentus, which has been a model system for studying the bacterial cell cycle, has an RNA degradosome assembly that is formed by the endoribonuclease RNase E and includes the DEAD-box RNA helicase RhlB. Immunoprecipitations of extracts from cells expressing an epitope-tagged RNase E reveal that RhlE, another member of the DEAD-box helicase family, associates with the degradosome at temperatures below those optimum for growth. Phenotype analyses of rhlE, rhlB, and rhlE rhlB mutant strains show that RhlE is important for cell fitness at low temperature and its role may not be substituted by RhlB. Transcriptional and translational fusions of rhlE to the lacZ reporter gene and immunoblot analysis of an epitope-tagged RhlE indicate that its expression is induced upon temperature decrease, mainly through posttranscriptional regulation. RNase E pulldown assays show that other proteins, including the transcription termination factor Rho, a second DEAD-box RNA helicase, and ribosomal protein S1, also associate with the degradosome at low temperature. The results suggest that the RNA degradosome assembly can be remodeled with environmental change to alter its repertoire of helicases and other accessory proteins. IMPORTANCE DEAD-box RNA helicases are often present in the RNA degradosome complex, helping unwind secondary structures to facilitate degradation. Caulobacter crescentus is an interesting organism to investigate degradosome remodeling with change in temperature, because it thrives in freshwater bodies and withstands low temperature. In this study, we show that at low temperature, the cold-induced DEAD-box RNA helicase RhlE is recruited to the RNA degradosome, along with other helicases and the Rho protein. RhlE is essential for bacterial fitness at low temperature, and its function may not be complemented by RhlB, although RhlE is able to complement for rhlB loss. These results suggest that RhlE has a specific role in the degradosome at low temperature, potentially improving adaptation to this condition.
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20
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Decreased Expression of Stable RNA Can Alleviate the Lethality Associated with RNase E Deficiency in Escherichia coli. J Bacteriol 2017; 199:JB.00724-16. [PMID: 28167522 DOI: 10.1128/jb.00724-16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/28/2017] [Indexed: 11/20/2022] Open
Abstract
The endoribonuclease RNase E participates in mRNA degradation, rRNA processing, and tRNA maturation in Escherichia coli, but the precise reasons for its essentiality are unclear and much debated. The enzyme is most active on RNA substrates with a 5'-terminal monophosphate, which is sensed by a domain in the enzyme that includes residue R169; E. coli also possesses a 5'-pyrophosphohydrolase, RppH, that catalyzes conversion of 5'-terminal triphosphate to 5'-terminal monophosphate on RNAs. Although the C-terminal half (CTH), beyond residue approximately 500, of RNase E is dispensable for viability, deletion of the CTH is lethal when combined with an R169Q mutation or with deletion of rppH In this work, we show that both these lethalities can be rescued in derivatives in which four or five of the seven rrn operons in the genome have been deleted. We hypothesize that the reduced stable RNA levels under these conditions minimize the need of RNase E to process them, thereby allowing for its diversion for mRNA degradation. In support of this hypothesis, we have found that other conditions that are known to reduce stable RNA levels also suppress one or both lethalities: (i) alterations in relA and spoT, which are expected to lead to increased basal ppGpp levels; (ii) stringent rpoB mutations, which mimic high intracellular ppGpp levels; and (iii) overexpression of DksA. Lethality suppression by these perturbations was RNase R dependent. Our work therefore suggests that its actions on the various substrates (mRNA, rRNA, and tRNA) jointly contribute to the essentiality of RNase E in E. coliIMPORTANCE The endoribonuclease RNase E is essential for viability in many Gram-negative bacteria, including Escherichia coli Different explanations have been offered for its essentiality, including its roles in global mRNA degradation or in the processing of several tRNA and rRNA species. Our work suggests that, rather than its role in the processing of any one particular substrate, its distributed functions on all the different substrates (mRNA, rRNA, and tRNA) are responsible for the essentiality of RNase E in E. coli.
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21
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Huen J, Lin CL, Golzarroshan B, Yi WL, Yang WZ, Yuan HS. Structural Insights into a Unique Dimeric DEAD-Box Helicase CshA that Promotes RNA Decay. Structure 2017; 25:469-481. [PMID: 28238534 DOI: 10.1016/j.str.2017.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/05/2017] [Accepted: 01/29/2017] [Indexed: 11/28/2022]
Abstract
CshA is a dimeric DEAD-box helicase that cooperates with ribonucleases for mRNA turnover. The molecular mechanism for how a dimeric DEAD-box helicase aids in RNA decay remains unknown. Here, we report the crystal structure and small-angle X-ray scattering solution structure of the CshA from Geobacillus stearothermophilus. In contrast to typical monomeric DEAD-box helicases, CshA is exclusively a dimeric protein with the RecA-like domains of each protomer forming a V-shaped structure. We show that the C-terminal domains protruding outward from the tip of the V-shaped structure is critical for mediating strong RNA binding and is crucial for efficient RNA-dependent ATP hydrolysis. We also show that RNA remains bound with CshA during ATP hydrolysis cycles and thus bulk RNAs could be unwound and degraded in a processive manner through cooperation between exoribonucleases and CshA. A dimeric helicase is hence preserved in RNA-degrading machinery for efficient RNA turnover in prokaryotes and eukaryotes.
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Affiliation(s)
- Jennifer Huen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Chia-Liang Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Bagher Golzarroshan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC; Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC; Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan 30013, ROC
| | - Wan-Li Yi
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Wei-Zen Yang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC; Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, ROC.
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22
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Cho KH. The Structure and Function of the Gram-Positive Bacterial RNA Degradosome. Front Microbiol 2017; 8:154. [PMID: 28217125 PMCID: PMC5289998 DOI: 10.3389/fmicb.2017.00154] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 01/20/2017] [Indexed: 11/24/2022] Open
Abstract
The RNA degradosome is a highly structured protein complex responsible for bulk RNA decay in bacteria. The main components of the complex, ribonucleases, an RNA helicase, and glycolytic enzymes are well-conserved in bacteria. Some components of the degradosome are essential for growth and the disruption of degradosome formation causes slower growth, indicating that this complex is required for proper cellular function. The study of the Escherichia coli degradosome has been performed extensively for the last several decades and has revealed detailed information on its structure and function. On the contrary, the Gram-positive bacterial degradosome, which contains ribonucleases different from the E. coli one, has been studied only recently. Studies on the Gram-positive degradosome revealed that its major component RNase Y was necessary for the full virulence of medically important Gram-positive bacterial pathogens, suggesting that it could be a target of antimicrobial therapy. This review describes the structures and function of Gram-positive bacterial RNA degradosomes, especially those of a Gram-positive model organism Bacillus subtilis, and two important Gram-positive pathogens, Staphylococcus aureus and Streptococcus pyogenes.
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Affiliation(s)
- Kyu Hong Cho
- Department of Biology, Indiana State University Terre Haute, IN, USA
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23
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Tseng YT, Chiou NT, Gogiraju R, Lin-Chao S. The Protein Interaction of RNA Helicase B (RhlB) and Polynucleotide Phosphorylase (PNPase) Contributes to the Homeostatic Control of Cysteine in Escherichia coli. J Biol Chem 2015; 290:29953-63. [PMID: 26494621 PMCID: PMC4705995 DOI: 10.1074/jbc.m115.691881] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/12/2022] Open
Abstract
PNPase, one of the major enzymes with 3′ to 5′ single-stranded RNA degradation and processing activities, can interact with the RNA helicase RhlB independently of RNA degradosome formation in Escherichia coli. Here, we report that loss of interaction between RhlB and PNPase impacts cysteine homeostasis in E. coli. By random mutagenesis, we identified a mutant RhlBP238L that loses 75% of its ability to interact with PNPase but retains normal interaction with RNase E and RNA, in addition to exhibiting normal helicase activity. Applying microarray analyses to an E. coli strain with impaired RNA degradosome formation, we investigated the biological consequences of a weakened interaction between RhlB and PNPase. We found significant increases in 11 of 14 genes involved in cysteine biosynthesis. Subsequent Northern blot analyses showed that the up-regulated transcripts were the result of stabilization of the cysB transcript encoding a transcriptional activator for the cys operons. Furthermore, Northern blots of PNPase or RhlB mutants showed that RhlB-PNPase plays both a catalytic and structural role in regulating cysB degradation. Cells expressing the RhlBP238L mutant exhibited an increase in intracellular cysteine and an enhanced anti-oxidative response. Collectively, this study suggests a mechanism by which bacteria use the PNPase-RhlB exosome-like complex to combat oxidative stress by modulating cysB mRNA degradation.
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Affiliation(s)
- Yi-Ting Tseng
- From the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, the Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10617, Taiwan
| | - Ni-Ting Chiou
- From the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan, the Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei 11221, Taiwan
| | | | - Sue Lin-Chao
- From the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan,
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24
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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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25
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Abstract
This review provides a description of the known Escherichia coli ribonucleases (RNases), focusing on their structures, catalytic properties, genes, physiological roles, and possible regulation. Currently, eight E. coli exoribonucleases are known. These are RNases II, R, D, T, PH, BN, polynucleotide phosphorylase (PNPase), and oligoribonuclease (ORNase). Based on sequence analysis and catalytic properties, the eight exoribonucleases have been grouped into four families. These are the RNR family, including RNase II and RNase R; the DEDD family, including RNase D, RNase T, and ORNase; the RBN family, consisting of RNase BN; and the PDX family, including PNPase and RNase PH. Seven well-characterized endoribonucleases are known in E. coli. These are RNases I, III, P, E, G, HI, and HII. Homologues to most of these enzymes are also present in Salmonella. Most of the endoribonucleases cleave RNA in the presence of divalent cations, producing fragments with 3'-hydroxyl and 5'-phosphate termini. RNase H selectively hydrolyzes the RNA strand of RNA?DNA hybrids. Members of the RNase H family are widely distributed among prokaryotic and eukaryotic organisms in three distinct lineages, RNases HI, HII, and HIII. It is likely that E. coli contains additional endoribonucleases that have not yet been characterized. First of all, endonucleolytic activities are needed for certain known processes that cannot be attributed to any of the known enzymes. Second, homologues of known endoribonucleases are present in E. coli. Third, endonucleolytic activities have been observed in cell extracts that have different properties from known enzymes.
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26
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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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27
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Redder P, Hausmann S, Khemici V, Yasrebi H, Linder P. Bacterial versatility requires DEAD-box RNA helicases. FEMS Microbiol Rev 2015; 39:392-412. [PMID: 25907111 DOI: 10.1093/femsre/fuv011] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 11/13/2022] Open
Abstract
RNA helicases of the DEAD-box and DEAH-box families are important players in many processes involving RNA molecules. These proteins can modify RNA secondary structures or intermolecular RNA interactions and modulate RNA-protein complexes. In bacteria, they are known to be involved in ribosome biogenesis, RNA turnover and translation initiation. They thereby play an important role in the adaptation of bacteria to changing environments and to respond to stress conditions.
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Affiliation(s)
- Peter Redder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Stéphane Hausmann
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Vanessa Khemici
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Haleh Yasrebi
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, 1, rue Michel Servet, CH 1211 Geneva 4, Switzerland
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28
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Aït-Bara S, Carpousis AJ, Quentin Y. RNase E in the γ-Proteobacteria: conservation of intrinsically disordered noncatalytic region and molecular evolution of microdomains. Mol Genet Genomics 2014; 290:847-62. [PMID: 25432321 PMCID: PMC4435900 DOI: 10.1007/s00438-014-0959-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/11/2014] [Indexed: 12/19/2022]
Abstract
RNase E of Escherichia coli is a membrane-associated endoribonuclease that has a major role in mRNA degradation. The enzyme has a large C-terminal noncatalytic region that is mostly intrinsically disordered (ID). Under standard growth conditions, RhlB, enolase and PNPase associate with the noncatalytic region to form the multienzyme RNA degradosome. To elucidate the origin and evolution of the RNA degradosome, we have identified and characterized orthologs of RNase E in the γ-Proteobacteria, a phylum of bacteria with diverse ecological niches and metabolic phenotypes and an ancient origin contemporary with the radiation of animals, plants and fungi. Intrinsic disorder, composition bias and tandem sequence repeats are conserved features of the noncatalytic region. Composition bias is bipartite with a catalytic domain proximal ANR-rich region and distal AEPV-rich region. Embedded in the noncatalytic region are microdomains (also known as MoRFs, MoREs or SLiMs), which are motifs that interact with protein and other ligands. Our results suggest that tandem repeat sequences are the progenitors of microdomains. We have identified 24 microdomains with phylogenetic signals that were acquired once with few losses. Microdomains involved in membrane association and RNA binding are universally conserved suggesting that they were present in ancestral RNase E. The RNA degradosome of E. coli arose in two steps with RhlB and PNPase acquisition early in a major subtree of the γ-Proteobacteria and enolase acquisition later. We propose a mechanism of microdomain acquisition and evolution and discuss implications of these results for the structure and function of the multienzyme RNA degradosome.
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Affiliation(s)
- Soraya Aït-Bara
- Laboratoire de Microbiologie et Génétique Moléculaires, UMR 5100, Centre National de la Recherche Scientifique and Université Paul Sabatier, 118, route de Narbonne, 31062, Toulouse Cedex 9, France
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29
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Wang DDH, Guo XE, Modrek AS, Chen CF, Chen PL, Lee WH. Helicase SUV3, polynucleotide phosphorylase, and mitochondrial polyadenylation polymerase form a transient complex to modulate mitochondrial mRNA polyadenylated tail lengths in response to energetic changes. J Biol Chem 2014; 289:16727-35. [PMID: 24770417 DOI: 10.1074/jbc.m113.536540] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian mitochondrial mRNA (mt-mRNA) transcripts are polyadenylated at the 3' end with different lengths. The SUV3·PNPase complex and mtPAP have been shown to degrade and polyadenylate mt mRNA, respectively. How these two opposite actions are coordinated to modulate mt-mRNA poly(A) lengths is of interest to pursue. Here, we demonstrated that a fraction of the SUV3·PNPase complex interacts with mitochondrial polyadenylation polymerase (mtPAP) under low mitochondrial matrix inorganic phosphate (Pi) conditions. In vitro binding experiments using purified proteins suggested that SUV3 binds to mtPAP through the N-terminal region around amino acids 100-104, distinctive from the C-terminal region around amino acids 510-514 of SUV3 for PNPase binding. mtPAP does not interact with PNPase directly, and SUV3 served as a bridge capable of simultaneously binding with mtPAP and PNPase. The complex consists of a SUV3 dimer, a mtPAP dimer, and a PNPase trimer, based on the molecular sizing experiments. Mechanistically, SUV3 provides a robust single strand RNA binding domain to enhance the polyadenylation activity of mtPAP. Furthermore, purified SUV3·PNPase·mtPAP complex is capable of lengthening or shortening the RNA poly(A) tail lengths in low or high Pi/ATP ratios, respectively. Consistently, the poly(A) tail lengths of mt-mRNA transcripts can be lengthened or shortened by altering the mitochondrial matrix Pi levels via selective inhibition of the electron transport chain or ATP synthase, respectively. Taken together, these results suggested that SUV3·PNPase·mtPAP form a transient complex to modulate mt-mRNA poly(A) tail lengths in response to cellular energy changes.
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Affiliation(s)
- Dennis Ding-Hwa Wang
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and
| | - Xuning Emily Guo
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and
| | - Aram Sandaldjian Modrek
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and
| | - Chi-Fen Chen
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and
| | - Phang-Lang Chen
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and
| | - Wen-Hwa Lee
- From the Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California 92697 and the Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan
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Zhang JY, Deng XM, Li FP, Wang L, Huang QY, Zhang CC, Chen WL. RNase E forms a complex with polynucleotide phosphorylase in cyanobacteria via a cyanobacterial-specific nonapeptide in the noncatalytic region. RNA (NEW YORK, N.Y.) 2014; 20:568-579. [PMID: 24563514 PMCID: PMC3964918 DOI: 10.1261/rna.043513.113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 01/23/2014] [Indexed: 05/29/2023]
Abstract
RNase E, a central component involved in bacterial RNA metabolism, usually has a highly conserved N-terminal catalytic domain but an extremely divergent C-terminal domain. While the C-terminal domain of RNase E in Escherichia coli recruits other components to form an RNA degradation complex, it is unknown if a similar function can be found for RNase E in other organisms due to the divergent feature of this domain. Here, we provide evidence showing that RNase E forms a complex with another essential ribonuclease-the polynucleotide phosphorylase (PNPase)-in cyanobacteria, a group of ecologically important and phylogenetically ancient organisms. Sequence alignment for all cyanobacterial RNase E proteins revealed several conserved and variable subregions in their noncatalytic domains. One such subregion, an extremely conserved nonapeptide (RRRRRRSSA) located near the very end of RNase E, serves as the PNPase recognition site in both the filamentous cyanobacterium Anabaena PCC7120 and the unicellular cyanobacterium Synechocystis PCC6803. These results indicate that RNase E and PNPase form a ribonuclease complex via a common mechanism in cyanobacteria. The PNPase-recognition motif in cyanobacterial RNase E is distinct from those previously identified in Proteobacteria, implying a mechanism of coevolution for PNPase and RNase E in different organisms.
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Affiliation(s)
- Ju-Yuan Zhang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xue-Mei Deng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Feng-Pu Li
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Li Wang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiao-Yun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Cheng-Cai Zhang
- Aix-Marseille Université and CNRS, Laboratoire de Chimie Bactérienne–UMR7283, 13402 Marseille cedex 20, France
| | - Wen-Li Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
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Kime L, Clarke JE, Romero A. D, Grasby JA, McDowall KJ. Adjacent single-stranded regions mediate processing of tRNA precursors by RNase E direct entry. Nucleic Acids Res 2014; 42:4577-89. [PMID: 24452799 PMCID: PMC3985628 DOI: 10.1093/nar/gkt1403] [Citation(s) in RCA: 23] [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: 10/24/2013] [Revised: 12/09/2013] [Accepted: 12/22/2013] [Indexed: 01/06/2023] Open
Abstract
The RNase E family is renowned for being central to the processing and decay of all types of RNA in many species of bacteria, as well as providing the first examples of endonucleases that can recognize 5'-monophosphorylated ends thereby increasing the efficiency of cleavage. However, there is increasing evidence that some transcripts can be cleaved efficiently by Escherichia coli RNase E via direct entry, i.e. in the absence of the recognition of a 5'-monophosphorylated end. Here, we provide biochemical evidence that direct entry is central to the processing of transfer RNA (tRNA) in E. coli, one of the core functions of RNase E, and show that it is mediated by specific unpaired regions that are adjacent, but not contiguous to segments cleaved by RNase E. In addition, we find that direct entry at a site on the 5' side of a tRNA precursor triggers a series of 5'-monophosphate-dependent cleavages. Consistent with a major role for direct entry in tRNA processing, we provide additional evidence that a 5'-monophosphate is not required to activate the catalysis step in cleavage. Other examples of tRNA precursors processed via direct entry are also provided. Thus, it appears increasingly that direct entry by RNase E has a major role in bacterial RNA metabolism.
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Affiliation(s)
- Louise Kime
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK and Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Justin E. Clarke
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK and Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - David Romero A.
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK and Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Jane A. Grasby
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK and Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Kenneth J. McDowall
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK and Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
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Abstract
Superfamily 2 helicase proteins are ubiquitous in RNA biology and have an extraordinarily broad set of functional roles. Central among these roles are the promotion of rearrangements of structured RNAs and the remodeling of ribonucleoprotein complexes (RNPs), allowing formation of native RNA structure or progression through a functional cycle of structures. Although all superfamily 2 helicases share a conserved helicase core, they are divided evolutionarily into several families, and it is principally proteins from three families, the DEAD-box, DEAH/RHA, and Ski2-like families, that function to manipulate structured RNAs and RNPs. Strikingly, there are emerging differences in the mechanisms of these proteins, both between families and within the largest family (DEAD-box), and these differences appear to be tuned to their RNA or RNP substrates and their specific roles. This review outlines basic mechanistic features of the three families and surveys individual proteins and the current understanding of their biological substrates and mechanisms.
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Affiliation(s)
- Inga Jarmoskaite
- Department of Molecular Biosciences and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712; ,
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33
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Kyriakou E, Chatzoglou E, Zouros E, Rodakis GC. The rRNA and tRNA transcripts of maternally and paternally inherited mitochondrial DNAs of Mytilus galloprovincialis suggest presence of a "degradosome" in mussel mitochondria and necessitate the re-annotation of the l-rRNA/CR boundary. Gene 2014; 540:78-85. [PMID: 24561285 DOI: 10.1016/j.gene.2014.01.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/15/2014] [Accepted: 01/21/2014] [Indexed: 11/24/2022]
Abstract
Species of the genus Mytilus carry two mitochondrial genomes in obligatory coexistence; one transmitted though the eggs (the F type) and one through the sperm (the M type). We have studied the 3' and 5' ends of rRNA and tRNA transcripts using RT-PCR and RNA circularization techniques in both the F and M genomes of Mytilus galloprovincialis. We have found polyadenylated and non-adenylated transcripts for both ribosomal and transfer RNAs. In all these genes the 5' ends of the transcripts coincided with the first nucleotide of the annotated genes, but the 3' ends were heterogeneous. The l-rRNA 3' end is 47 or 48 nucleotides upstream from the one assigned by a previous annotation, which makes the adjacent first domain (variable domain one, VD1) of the main control region (CR) correspondingly longer. We have observed s-rRNA and l-rRNA transcripts with truncated 3' end and polyadenylated tRNA transcripts carrying the CCA trinucleotide. We have also detected polyadenylated RNA remnants carrying the sequences of the control region, which strongly suggests RNA degradation activity and thus presence of degradosomes in Mytilus mitochondria.
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Affiliation(s)
- Eleni Kyriakou
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15701 Athens, Greece
| | - Evanthia Chatzoglou
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15701 Athens, Greece
| | - Eleftherios Zouros
- Department of Biology, University of Crete, 71409 Heraklion, Crete, Greece
| | - George C Rodakis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15701 Athens, Greece.
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Mazurkewich S, Wang W, Seah SYK. Biochemical and structural analysis of RraA proteins to decipher their relationships with 4-hydroxy-4-methyl-2-oxoglutarate/4-carboxy-4-hydroxy-2-oxoadipate aldolases. Biochemistry 2014; 53:542-53. [PMID: 24359411 DOI: 10.1021/bi401486g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
4-Hydroxy-4-methyl-2-oxoglutarate (HMG)/4-carboxy-4-hydroxy-2-oxoadipate (CHA) aldolases are class II (divalent metal ion dependent) pyruvate aldolases from the meta cleavage pathways of protocatechuate and gallate. The enzyme from Pseudomonas putida F1 is structurally similar to a group of proteins termed regulators of RNase E activity A (RraA) that bind to the regulatory domain of RNase E and inhibit the ribonuclease activity in certain bacteria. Analysis of homologous RraA-like proteins from varying species revealed that they share sequence conservation within the active site of HMG/CHA aldolase. In particular, the P. putida F1 HMG/CHA aldolase has a D-X20-R-D motif, whereas a G-X20-R-D-X2-E/D motif is observed in the structures of the RraA-like proteins from Thermus thermophilus HB8 (TtRraA) and Saccharomyces cerevisiae S288C (Yer010Cp) that may support metal binding. TtRraA and Yer010Cp were found to contain HMG aldolase and oxaloacetate decarboxylase activities. Similar to the P. putida F1 HMG/CHA aldolase, both TtRraA and Yer010Cp enzymes required divalent metal ions for activity and were competitively inhibited by oxalate, a pyruvate enolate analogue, suggesting a common mechanism among the enzymes. The RraA from Escherichia coli (EcRraA) lacked detectable C-C lyase activity. Upon restoration of the G-X20-R-D-X2-E/D motif, by site-specific mutagenesis, the EcRraA variant was able to catalyze oxaloacetate decarboxylation. Sequence analysis of RraA-like gene products found across all the domains of life revealed conservation of the metal binding motifs that can likely support a divalent metal ion-dependent enzyme reaction either in addition to or in place of the putative RraA function.
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Affiliation(s)
- Scott Mazurkewich
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada N1G 5E9
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35
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Rorbach J, Bobrowicz A, Pearce S, Minczuk M. Polyadenylation in bacteria and organelles. Methods Mol Biol 2014; 1125:211-27. [PMID: 24590792 DOI: 10.1007/978-1-62703-971-0_18] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Polyadenylation is a posttranscriptional modification present throughout all the kingdoms of life with important roles in regulation of RNA stability, translation, and quality control. Functions of polyadenylation in prokaryotic and organellar RNA metabolism are still not fully characterized, and poly(A) tails appear to play contrasting roles in different systems. Here we present a general overview of the polyadenylation process and the factors involved in its regulation, with an emphasis on the diverse functions of 3' end modification in the control of gene expression in different biological systems.
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Affiliation(s)
- Joanna Rorbach
- Mitochondrial Genetics Group, MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK,
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36
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The assembly and distribution in vivo of the Escherichia coli RNA degradosome. Biochimie 2013; 95:2034-41. [DOI: 10.1016/j.biochi.2013.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 07/12/2013] [Indexed: 11/18/2022]
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37
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Chatzoglou E, Kyriakou E, Zouros E, Rodakis GC. The mRNAs of maternally and paternally inherited mtDNAs of the mussel Mytilus galloprovincialis: Start/end points and polycistronic transcripts. Gene 2013; 520:156-65. [DOI: 10.1016/j.gene.2013.02.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 02/07/2013] [Indexed: 10/27/2022]
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38
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Abstract
RNA enables the material interpretation of genetic information through time and in space. The creation, destruction and activity of RNA must be well controlled and tightly synchronized with numerous cellular processes. We discuss here the pathways and mechanism of bacterial RNA turnover, and describe how RNA itself modulates these processes as part of decision-making networks. The central roles of RNA decay and other aspects of RNA metabolism in cellular control are also suggested by their vulnerability to sabotage by phages; nonetheless, RNA can be used in defense against phage infection, and these processes are described here. Salient aspects of RNA turnover are drawn together to suggest how it could affect complex effects such as phenotypic diversity in populations and responses that persist for multiple generations.
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Bandyra KJ, Bouvier M, Carpousis AJ, Luisi BF. The social fabric of the RNA degradosome. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:514-22. [PMID: 23459248 PMCID: PMC3991390 DOI: 10.1016/j.bbagrm.2013.02.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 11/22/2022]
Abstract
Bacterial transcripts each have a characteristic half-life, suggesting that the processes of RNA degradation work in an active and selective manner. Moreover, the processes are well controlled, thereby ensuring that degradation is orderly and coordinated. Throughout much of the bacterial kingdom, RNA degradation processes originate through the actions of assemblies of key RNA enzymes, known as RNA degradosomes. Neither conserved in composition, nor unified by common evolutionary ancestry, RNA degradosomes nonetheless can be found in divergent bacterial lineages, implicating a common requirement for the co-localisation of RNA metabolic activities. We describe how the cooperation of components in the representative degradosome of Escherichia coli may enable controlled access to transcripts, so that they have defined and programmable lifetimes. We also discuss how this cooperation contributes to precursor processing and to the riboregulation of intricate post-transcriptional networks in the control of gene expression. The E. coli degradosome interacts with the cytoplasmic membrane, and we discuss how this interaction may spatially organise the assembly and contribute to subunit cooperation and substrate capture. This article is part of a Special Issue entitled: RNA Decay mechanisms. The organisation of the bacterial RNA degradosome The role in riboregulation and proposal for mechanism Discussion of access to substrates Discussion of the function of compartmentalisation
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40
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Bacterial helicases in post-transcriptional control. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:878-83. [PMID: 23291566 DOI: 10.1016/j.bbagrm.2012.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/17/2012] [Accepted: 12/20/2012] [Indexed: 12/25/2022]
Abstract
Among the five superfamilies of helicases involved in RNA and DNA metabolism, superfamily 2 and superfamily 5 include bacterial RNA-helicases. These enzymes have been shown to be involved in ribosome biogenesis and post-transcriptional gene regulation. Here, we focus on bacterial regulatory mechanisms that are mediated by RNA helicases belonging to superfamily 2, which includes DEAD-box and DEAH-box helicases. Some of these helicases are part of bacterial degradosomes and were shown to unwind RNA duplexes. We will review examples where these enzymes have been implicated in translatability and metabolic stability of bacterial transcripts. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life.
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41
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Mackie GA. RNase E: at the interface of bacterial RNA processing and decay. Nat Rev Microbiol 2012; 11:45-57. [DOI: 10.1038/nrmicro2930] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Oun S, Redder P, Didier JP, François P, Corvaglia AR, Buttazzoni E, Giraud C, Girard M, Schrenzel J, Linder P. The CshA DEAD-box RNA helicase is important for quorum sensing control in Staphylococcus aureus. RNA Biol 2012; 10:157-65. [PMID: 23229022 PMCID: PMC3590232 DOI: 10.4161/rna.22899] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
DEAD-box RNA helicases are present in almost all living organisms and participate in various processes of RNA metabolism. Bacterial proteins of this large family were shown to be required for translation initiation, ribosome biogenesis and RNA decay. The latter is primordial for rapid adaptation to changing environmental conditions. In particular, the RhlB RNA helicase from E. coli was shown to assist the bacterial degradosome machinery. Recently, the CshA DEAD-box proteins from Bacillus subtilis and Staphylococcus aureus were shown to interact with proteins that are believed to form the degradosome. S. aureus can cause life-threatening disease, with particular concern focusing on biofilm formation on catheters and prosthetic devices, since in this form the bacteria are almost impossible to eradicate both by the immune system and antibiotic treatment. This persistent state relies on the expression of surface encoded proteins that allow attachment to various surfaces, and contrasts with the dispersal mode of growth that relies on the secretion of proteins such as hemolysins and proteases. The switch between these two states is mainly mediated by the Staphylococcal cell density sensing system encoded by agr. We show that inactivation of the cshA DEAD-box gene results in dysregulation of biofilm formation and hemolysis through modulation of agr mRNA stability. Importantly, inactivation of the agrA gene in the cshA mutant background reverses the defect, indicating that cshA is genetically upstream of agr and that a delicate balance of agr mRNA abundance mediated through stability control by CshA is critical for proper expression of virulence factors.
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Affiliation(s)
- Stella Oun
- Department of Microbiology and Molecular Medicine, CMU, Medical Faculty, University of Geneva, Genève, Switzerland
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43
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Abstract
Similar to proteins, RNA molecules must fold into the correct conformation and associate with protein complexes in order to be functional within a cell. RNA helicases rearrange RNA secondary structure and RNA-protein interactions in an ATP-dependent reaction, performing crucial functions in all aspects of RNA metabolism. In prokaryotes, RNA helicase activity is associated with roles in housekeeping functions including RNA turnover, ribosome biogenesis, translation and small RNA metabolism. In addition, RNA helicase expression and/or activity are frequently altered during cellular response to abiotic stress, implying they perform defined roles during cellular adaptation to changes in the growth environment. Specifically, RNA helicases contribute to the formation of cold-adapted ribosomes and RNA degradosomes, implying a role in alleviation of RNA secondary structure stabilization at low temperature. A common emerging theme involves RNA helicases acting as scaffolds for protein-protein interaction and functioning as molecular clamps, holding RNA-protein complexes in specific conformations. This review highlights recent advances in DEAD-box RNA helicase association with cellular response to abiotic stress in prokaryotes.
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Affiliation(s)
- George W Owttrim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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44
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Hardwick SW, Luisi BF. Rarely at rest: RNA helicases and their busy contributions to RNA degradation, regulation and quality control. RNA Biol 2012; 10:56-70. [PMID: 23064154 DOI: 10.4161/rna.22270] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
RNA helicases are compact, machine-like proteins that can harness the energy of nucleoside triphosphate binding and hydrolysis to dynamically remodel RNA structures and protein-RNA complexes. Through such activities, helicases participate in virtually every process associated with the expression of genetic information. Often found as components of multi-enzyme assemblies, RNA helicases facilitate the processivity of RNA degradation, the remodeling of protein interactions during maturation of structured RNA precursors, and fidelity checks of RNA quality. In turn, the assemblies modulate and guide the activities of the helicases. We describe the roles of RNA helicases with a conserved "DExD/H box" sequence motif in representative examples of such machineries from bacteria, archaea and eukaryotes. The recurrent occurrence of such helicases in complex assemblies throughout the course of evolution suggests a common requirement for their activities to meet cellular demands for the dynamic control of RNA metabolism.
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45
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Henry A, Shanks J, van Hoof A, Rosenzweig JA. The Yersinia pseudotuberculosis degradosome is required for oxidative stress, while its PNPase subunit plays a degradosome-independent role in cold growth. FEMS Microbiol Lett 2012; 336:139-47. [PMID: 23082859 DOI: 10.1111/j.1574-6968.12000.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/14/2012] [Accepted: 08/24/2012] [Indexed: 01/01/2023] Open
Abstract
Yersinia polynucleotide phosphorylase (PNPase), a 3'-5' exoribonuclease, has been shown to affect growth during several stress responses. In Escherichia coli, PNPase is one of the subunits of a multiprotein complex known as the degradosome, but also has degradosome-independent functions. The carboxy-terminus of E. coli ribonuclease E (RNase E) serves as the scaffold upon which PNPase, enolase (a glycolytic enzyme), and RhlB helicase all have been shown to bind. In the yersiniae, only PNPase has thus far been shown to physically interact with RNase E. We show by bacterial two-hybrid and co-immunoprecipitation assays that RhlB and enolase also interact with RNase E. Interestingly, although PNPase is required for normal growth at cold temperatures, assembly of the yersiniae degradosome was not required. However, degradosome assembly was required for growth in the presence of reactive oxygen species. These data suggest that while the Yersinia pseudotuberculosis PNPase plays a role in the oxidative stress response through a degradosome-dependent mechanism, PNPase's role during cold stress is degradosome-independent.
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Affiliation(s)
- Amanda Henry
- Department of Biology, Center for Bionanotechnology and Environmental Research (CBER), Texas Southern University, Houston, TX, USA
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46
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Abstract
Escherichia coli contains multiple 3' to 5' RNases, of which two, RNase PH and polynucleotide phosphorylase (PNPase), use inorganic phosphate as a nucleophile to catalyze RNA cleavage. It is known that an absence of these two enzymes causes growth defects, but the basis for these defects has remained undefined. To further an understanding of the function of these enzymes, the degradation pattern of different cellular RNAs was analyzed. It was observed that an absence of both enzymes results in the appearance of novel mRNA degradation fragments. Such fragments were also observed in strains containing mutations in RNase R and PNPase, enzymes whose collective absence is known to cause an accumulation of structured RNA fragments. Additional experiments indicated that the growth defects of strains containing RNase R and PNPase mutations were exacerbated upon RNase PH removal. Taken together, these observations suggested that RNase PH could play a role in structured RNA degradation. Biochemical experiments with RNase PH demonstrated that this enzyme digests through RNA duplexes of moderate stability. In addition, mapping and sequence analysis of an mRNA degradation fragment that accumulates in the absence of the phosphorolytic enzymes revealed the presence of an extended stem-loop motif at the 3' end. Overall, these results indicate that RNase PH plays a novel role in the degradation of structured RNAs and provides a potential explanation for the growth defects caused by an absence of the phosphorolytic RNases.
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47
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Mohanty BK, Kushner SR. Bacterial/archaeal/organellar polyadenylation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 2:256-76. [PMID: 21344039 DOI: 10.1002/wrna.51] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although the first poly(A) polymerase (PAP) was discovered in Escherichia coli in 1962, the study of polyadenylation in bacteria was largely ignored for the next 30 years. However, with the identification of the structural gene for E. coli PAP I in 1992, it became possible to analyze polyadenylation using both biochemical and genetic approaches. Subsequently, it has been shown that polyadenylation plays a multifunctional role in prokaryotic RNA metabolism. Although the bulk of our current understanding of prokaryotic polyadenylation comes from studies on E. coli, recent limited experiments with Cyanobacteria, organelles, and Archaea have widened our view on the diversity, complexity, and universality of the polyadenylation process. For example, the identification of polynucleotide phosphorylase (PNPase), a reversible phosphorolytic enzyme that is highly conserved in bacteria, as an additional PAP in E. coli caught everyone by surprise. In fact, PNPase has now been shown to be the source of post-transcriptional RNA modifications in a wide range of cells of prokaryotic origin including those that lack a eubacterial PAP homolog. Accordingly, the past few years have witnessed increased interest in the mechanism and role of post-transcriptional modifications in all species of prokaryotic origin. However, the fact that many of the poly(A) tails are very short and unstable as well as the presence of polynucleotide tails has posed significant technical challenges to the scientific community trying to unravel the mystery of polyadenylation in prokaryotes. This review discusses the current state of knowledge regarding polyadenylation and its functions in bacteria, organelles, and Archaea.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, GA 30605, USA
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48
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Rath D, Mangoli SH, Pagedar AR, Jawali N. Involvement of pnp in survival of UV radiation in Escherichia coli K-12. MICROBIOLOGY-SGM 2012; 158:1196-1205. [PMID: 22322961 DOI: 10.1099/mic.0.056309-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Polynucleotide phosphorylase (PNPase), a multifunctional protein, is a 3'→5' exoribonuclease or exoDNase in the presence of inorganic phosphate (P(i)), and extends a 3'-OH of RNA or ssDNA in the presence of ADP or dADP. In Escherichia coli, PNPase is known to protect against H(2)O(2)- and mitomycin C-induced damage. Recent reports show that Bacillus subtilis PNPase is required for repair of H(2)O(2)-induced double-strand breaks. Here we show that absence of PNPase makes E. coli cells sensitive to UV, indicating that PNPase has a role in survival of UV radiation damage. Analyses of various DNA repair pathways show that in the absence of nucleotide excision repair, survival of UV radiation depends critically on PNPase function. Consequently, uvrA pnp, uvrB pnp and uvrC pnp strains show hypersensitivity to UV radiation. Whereas the pnp mutation is non-epistatic to recJ, recQ and recG mutations with respect to the UV-sensitivity phenotype, it is epistatic to uvrD, recB and ruvA mutations, implicating it in the recombinational repair process.
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Affiliation(s)
- Devashish Rath
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Suhas H Mangoli
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Amruta R Pagedar
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Narendra Jawali
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Morrison JM, Dunman PM. The modulation of Staphylococcus aureus mRNA turnover. Future Microbiol 2012; 6:1141-50. [PMID: 22004033 DOI: 10.2217/fmb.11.102] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus is a Gram-positive pathogen capable of causing a wide array of infections owing, in large part, to the coordinated expression of an extensive repertoire of virulence factors. Our laboratory and others have shown that the expression of these factors can occur post-transcriptionally at the level of mRNA turnover and is mediated by ribonucleases, RNA-binding proteins, and regulatory RNA molecules. Moreover, S. aureus harbors the ability to alter the stability of its mRNA titers in response to physiological stresses, including antibiotic exposure. Although ongoing studies are attempting to identify the molecular components that modulate S. aureus mRNA turnover, innovative approaches to target these essential processes have established a novel group of targets for therapeutic development against staphylococcal infections.
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Affiliation(s)
- John M Morrison
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
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50
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Chi W, He B, Mao J, Li Q, Ma J, Ji D, Zou M, Zhang L. The function of RH22, a DEAD RNA helicase, in the biogenesis of the 50S ribosomal subunits of Arabidopsis chloroplasts. PLANT PHYSIOLOGY 2012; 158:693-707. [PMID: 22170977 PMCID: PMC3271760 DOI: 10.1104/pp.111.186775] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 12/12/2011] [Indexed: 05/18/2023]
Abstract
The chloroplast ribosome is a large and dynamic ribonucleoprotein machine that is composed of the 30S and 50S subunits. Although the components of the chloroplast ribosome have been identified in the last decade, the molecular mechanisms driving chloroplast ribosome biogenesis remain largely elusive. Here, we show that RNA helicase 22 (RH22), a putative DEAD RNA helicase, is involved in chloroplast ribosome assembly in Arabidopsis (Arabidopsis thaliana). A loss of RH22 was lethal, whereas a knockdown of RH22 expression resulted in virescent seedlings with clear defects in chloroplast ribosomal RNA (rRNA) accumulation. The precursors of 23S and 4.5S, but not 16S, rRNA accumulated in rh22 mutants. Further analysis showed that RH22 was associated with the precursors of 50S ribosomal subunits. These results suggest that RH22 may function in the assembly of 50S ribosomal subunits in chloroplasts. In addition, RH22 interacted with the 50S ribosomal protein RPL24 through yeast two-hybrid and pull-down assays, and it was also bound to a small 23S rRNA fragment encompassing RPL24-binding sites. This action of RH22 may be similar to, but distinct from, that of SrmB, a DEAD RNA helicase that is involved in the ribosomal assembly in Escherichia coli, which suggests that DEAD RNA helicases and rRNA structures may have coevolved with respect to ribosomal assembly and function.
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Affiliation(s)
| | | | | | | | | | | | | | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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