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Kirsebom LA, Liu F, McClain WH. The discovery of a catalytic RNA within RNase P and its legacy. J Biol Chem 2024; 300:107318. [PMID: 38677513 PMCID: PMC11143913 DOI: 10.1016/j.jbc.2024.107318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 04/12/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024] Open
Abstract
Sidney Altman's discovery of the processing of one RNA by another RNA that acts like an enzyme was revolutionary in biology and the basis for his sharing the 1989 Nobel Prize in Chemistry with Thomas Cech. These breakthrough findings support the key role of RNA in molecular evolution, where replicating RNAs (and similar chemical derivatives) either with or without peptides functioned in protocells during the early stages of life on Earth, an era referred to as the RNA world. Here, we cover the historical background highlighting the work of Altman and his colleagues and the subsequent efforts of other researchers to understand the biological function of RNase P and its catalytic RNA subunit and to employ it as a tool to downregulate gene expression. We primarily discuss bacterial RNase P-related studies but acknowledge that many groups have significantly contributed to our understanding of archaeal and eukaryotic RNase P, as reviewed in this special issue and elsewhere.
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Affiliation(s)
- Leif A Kirsebom
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Fenyong Liu
- School of Public Health, University of California, Berkeley, California, USA.
| | - William H McClain
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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2
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Ikei M, Miyazaki R, Monden K, Naito Y, Takeuchi A, Takahashi YS, Tanaka Y, Murata K, Mori T, Ichikawa M, Tsukazaki T. YeeD is an essential partner for YeeE-mediated thiosulfate uptake in bacteria and regulates thiosulfate ion decomposition. PLoS Biol 2024; 22:e3002601. [PMID: 38656967 PMCID: PMC11073785 DOI: 10.1371/journal.pbio.3002601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/06/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Uptake of thiosulfate ions as an inorganic sulfur source from the environment is important for bacterial sulfur assimilation. Recently, a selective thiosulfate uptake pathway involving a membrane protein YeeE (TsuA) in Escherichia coli was characterized. YeeE-like proteins are conserved in some bacteria, archaea, and eukaryotes. However, the precise function of YeeE, along with its potential partner protein in the thiosulfate ion uptake pathway, remained unclear. Here, we assessed selective thiosulfate transport via Spirochaeta thermophila YeeE in vitro and characterized E. coli YeeD (TsuB) as an adjacent and essential protein for YeeE-mediated thiosulfate uptake in vivo. We further showed that S. thermophila YeeD possesses thiosulfate decomposition activity and that a conserved cysteine in YeeD was modified to several forms in the presence of thiosulfate. Finally, the crystal structures of S. thermophila YeeE-YeeD fusion proteins at 3.34-Å and 2.60-Å resolutions revealed their interactions. The association was evaluated by a binding assay using purified S. thermophila YeeE and YeeD. Based on these results, a model of the sophisticated uptake of thiosulfate ions by YeeE and YeeD is proposed.
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Affiliation(s)
- Mai Ikei
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Ryoji Miyazaki
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Keigo Monden
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yusuke Naito
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Azusa Takeuchi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yutaro S Takahashi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yoshiki Tanaka
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Keina Murata
- Department of Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takaharu Mori
- Department of Chemistry, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Muneyoshi Ichikawa
- State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Tomoya Tsukazaki
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan
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3
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Sridhara S. Multiple structural flavors of RNase P in precursor tRNA processing. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1835. [PMID: 38479802 DOI: 10.1002/wrna.1835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 06/06/2024]
Abstract
The precursor transfer RNAs (pre-tRNAs) require extensive processing to generate mature tRNAs possessing proper fold, structural stability, and functionality required to sustain cellular viability. The road to tRNA maturation follows an ordered process: 5'-processing, 3'-processing, modifications at specific sites, if any, and 3'-CCA addition before aminoacylation and recruitment to the cellular protein synthesis machinery. Ribonuclease P (RNase P) is a universally conserved endonuclease in all domains of life, performing the hydrolysis of pre-tRNA sequences at the 5' end by the removal of phosphodiester linkages between nucleotides at position -1 and +1. Except for an archaeal species: Nanoarchaeum equitans where tRNAs are transcribed from leaderless-position +1, RNase P is indispensable for life and displays fundamental variations in terms of enzyme subunit composition, mechanism of substrate recognition and active site architecture, utilizing in all cases a two metal ion-mediated conserved catalytic reaction. While the canonical RNA-based ribonucleoprotein RNase P has been well-known to occur in bacteria, archaea, and eukaryotes, the occurrence of RNA-free protein-only RNase P in eukaryotes and RNA-free homologs of Aquifex RNase P in prokaryotes has been discovered more recently. This review aims to provide a comprehensive overview of structural diversity displayed by various RNA-based and RNA-free RNase P holoenzymes towards harnessing critical RNA-protein and protein-protein interactions in achieving conserved pre-tRNA processing functionality. Furthermore, alternate roles and functional interchangeability of RNase P are discussed in the context of its employability in several clinical and biotechnological applications. This article is categorized under: RNA Processing > tRNA Processing RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Sagar Sridhara
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
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4
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Chamberlain AR, Huynh L, Huang W, Taylor DJ, Harris ME. The specificity landscape of bacterial ribonuclease P. J Biol Chem 2024; 300:105498. [PMID: 38013087 PMCID: PMC10731613 DOI: 10.1016/j.jbc.2023.105498] [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: 07/24/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
Developing quantitative models of substrate specificity for RNA processing enzymes is a key step toward understanding their biology and guiding applications in biotechnology and biomedicine. Optimally, models to predict relative rate constants for alternative substrates should integrate an understanding of structures of the enzyme bound to "fast" and "slow" substrates, large datasets of rate constants for alternative substrates, and transcriptomic data identifying in vivo processing sites. Such data are either available or emerging for bacterial ribonucleoprotein RNase P a widespread and essential tRNA 5' processing endonuclease, thus making it a valuable model system for investigating principles of biological specificity. Indeed, the well-established structure and kinetics of bacterial RNase P enabled the development of high throughput measurements of rate constants for tRNA variants and provided the necessary framework for quantitative specificity modeling. Several studies document the importance of conformational changes in the precursor tRNA substrate as well as the RNA and protein subunits of bacterial RNase P during binding, although the functional roles and dynamics are still being resolved. Recently, results from cryo-EM studies of E. coli RNase P with alternative precursor tRNAs are revealing prospective mechanistic relationships between conformational changes and substrate specificity. Yet, extensive uncharted territory remains, including leveraging these advances for drug discovery, achieving a complete accounting of RNase P substrates, and understanding how the cellular context contributes to RNA processing specificity in vivo.
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Affiliation(s)
| | - Loc Huynh
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, Florida, USA.
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5
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Trinquier A, Condon C, Braun F. Effect of tRNA Maturase Depletion on Levels and Stabilities of Ribosome Assembly Cofactor and Other mRNAs in Bacillus subtilis. Microbiol Spectr 2023; 11:e0513422. [PMID: 36840557 PMCID: PMC10100781 DOI: 10.1128/spectrum.05134-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/30/2023] [Indexed: 02/24/2023] Open
Abstract
The impact of translation on mRNA stability can be varied, ranging from a protective effect of ribosomes that shield mRNA from RNases to preferentially exposing sites of RNase cleavage. These effects can change depending on whether ribosomes are actively moving along the mRNA or stalled at particular sequences or structures or awaiting charged tRNAs. We recently observed that depleting Bacillus subtilis cells of their tRNA maturation enzymes RNase P and RNase Z led to altered mRNA levels of a number of assembly factors involved in the biogenesis of the 30S ribosomal subunit. Here, we extended this study to other assembly factor and non-assembly factor mRNAs in B. subtilis. We additionally identified multiple transcriptional and translational layers of regulation of the rimM operon mRNA that occur in response to the depletion of functional tRNAs. IMPORTANCE The passage of ribosomes across individual mRNAs during translation can have different effects on their degradation, ranging from a protective effect by shielding from ribonucleases to, in some cases, making the mRNA more vulnerable to RNase action. We recently showed that some mRNAs coding for proteins involved in ribosome assembly were highly sensitive to the availability of functional tRNA. Using strains depleted of the major tRNA processing enzymes RNase P and RNase Z, we expanded this observation to a wider set of mRNAs, including some unrelated to ribosome biogenesis. We characterized the impact of tRNA maturase depletion on the rimM operon mRNA and show that it is highly complex, with multiple levels of transcriptional and posttranscriptional effects coming into play.
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Affiliation(s)
- Aude Trinquier
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
| | - Ciarán Condon
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
| | - Frédérique Braun
- CNRS, Université Paris Cité, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
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6
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Wei G, Li S, Ye S, Wang Z, Zarringhalam K, He J, Wang W, Shao Z. High-Resolution Small RNAs Landscape Provides Insights into Alkane Adaptation in the Marine Alkane-Degrader Alcanivorax dieselolei B-5. Int J Mol Sci 2022; 23:ijms232415995. [PMID: 36555635 PMCID: PMC9788540 DOI: 10.3390/ijms232415995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Alkanes are widespread in the ocean, and Alcanivorax is one of the most ubiquitous alkane-degrading bacteria in the marine ecosystem. Small RNAs (sRNAs) are usually at the heart of regulatory pathways, but sRNA-mediated alkane metabolic adaptability still remains largely unknown due to the difficulties of identification. Here, differential RNA sequencing (dRNA-seq) modified with a size selection (~50-nt to 500-nt) strategy was used to generate high-resolution sRNAs profiling in the model species Alcanivorax dieselolei B-5 under alkane (n-hexadecane) and non-alkane (acetate) conditions. As a result, we identified 549 sRNA candidates at single-nucleotide resolution of 5'-ends, 63.4% of which are with transcription start sites (TSSs), and 36.6% of which are with processing sites (PSSs) at the 5'-ends. These sRNAs originate from almost any location in the genome, regardless of intragenic (65.8%), antisense (20.6%) and intergenic (6.2%) regions, and RNase E may function in the maturation of sRNAs. Most sRNAs locally distribute across the 15 reference genomes of Alcanivorax, and only 7.5% of sRNAs are broadly conserved in this genus. Expression responses to the alkane of several core conserved sRNAs, including 6S RNA, M1 RNA and tmRNA, indicate that they may participate in alkane metabolisms and result in more actively global transcription, RNA processing and stresses mitigation. Two novel CsrA-related sRNAs are identified, which may be involved in the translational activation of alkane metabolism-related genes by sequestering the global repressor CsrA. The relationships of sRNAs with the characterized genes of alkane sensing (ompS), chemotaxis (mcp, cheR, cheW2), transporting (ompT1, ompT2, ompT3) and hydroxylation (alkB1, alkB2, almA) were created based on the genome-wide predicted sRNA-mRNA interactions. Overall, the sRNA landscape lays the ground for uncovering cryptic regulations in critical marine bacterium, among which both the core and species-specific sRNAs are implicated in the alkane adaptive metabolisms.
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Affiliation(s)
- Guangshan Wei
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Sujie Li
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
| | - Sida Ye
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
- Center for Personalized Cancer Therapy, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Zining Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
| | - Kourosh Zarringhalam
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
- Center for Personalized Cancer Therapy, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Jianguo He
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Wanpeng Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Correspondence: (W.W.); (Z.S.)
| | - Zongze Shao
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
- Correspondence: (W.W.); (Z.S.)
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7
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Mohanty BK, Kushner SR. Processing of the alaW alaX operon encoding the Ala2 tRNAs in Escherichia coli requires both RNase E and RNase P. Mol Microbiol 2022; 118:698-715. [PMID: 36268779 DOI: 10.1111/mmi.14991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/06/2022] [Accepted: 10/18/2022] [Indexed: 01/18/2023]
Abstract
The alaW alaX operon encodes the Ala2 tRNAs, one of the two alanine tRNA isotypes in Escherichia coli. Our previous RNA-seq study showed that alaW alaX dicistronic RNA levels increased significantly in the absence of both RNase P and poly(A) polymerase I (PAP I), suggesting a role of polyadenylation in its stability. In this report, we show that RNase E initiates the processing of the primary alaW alaX precursor RNA by removing the Rho-independent transcription terminator, which appears to be the rate limiting step in the separation and maturation of the Ala2 pre-tRNAs by RNase P. Failure to separate the alaW and alaX pre-tRNAs by RNase P leads to poly(A)-mediated degradation of the dicistronic RNAs by polynucleotide phosphorylase (PNPase) and RNase R. Surprisingly, the thermosensitive RNase E encoded by the rne-1 allele is highly efficient in removing the terminator (>99%) at the nonpermissive temperature suggesting a significant caveat in experiments using this allele. Together, our data present a comprehensive picture of the Ala2 tRNA processing pathway and demonstrate that unprocessed RNase P substrates are degraded via a poly(A) mediated decay pathway.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, Georgia, USA
| | - Sidney R Kushner
- Department of Genetics, University of Georgia, Athens, Georgia, USA.,Microbiology, University of Georgia, Athens, Georgia, USA
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8
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Chen Y, Cheng M, Li Y, Wang L, Fang L, Cao Y, Song H. Highly efficient multiplex base editing: One-shot deactivation of eight genes in Shewanella oneidensis MR-1. Synth Syst Biotechnol 2022; 8:1-10. [PMID: 36313217 PMCID: PMC9594123 DOI: 10.1016/j.synbio.2022.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/15/2022] [Accepted: 09/28/2022] [Indexed: 11/03/2022] Open
Abstract
Obtaining electroactive microbes capable of efficient extracellular electron transfer is a large undertaking for the scalability of bio-electrochemical systems. Inevitably, researchers need to pursue the co-modification of multiple genes rather than expecting that modification of a single gene would make a significant contribution to improving extracellular electron transfer rates. Base editing has enabled highly-efficient gene deactivation in model electroactive microbe Shewanella oneidensis MR-1. Since multiplexed application of base editing is still limited by its low throughput procedure, we thus here develop a rapid and efficient multiplex base editing system in S. oneidensis. Four approaches to express multiple gRNAs were assessed firstly, and transcription of each gRNA cassette into a monocistronic unit was validated as a more favorable option than transcription of multiple gRNAs into a polycistronic cluster. Then, a smart scheme was designed to deliver one-pot assembly of multiple gRNAs. 3, 5, and 8 genes were deactivated using this system with editing efficiency of 83.3%, 100% and 12.5%, respectively. To offer some nonrepetitive components as alternatives genetic parts of sgRNA cassette, different promoters, handles, and terminators were screened. This multiplex base editing tool was finally adopted to simultaneously deactivate eight genes that were identified as significantly downregulated targets in transcriptome analysis of riboflavin-overproducing strain and control strain. The maximum power density of the multiplex engineered strain HRF(8BE) in microbial fuel cells was 1108.1 mW/m2, which was 21.67 times higher than that of the wild-type strain. This highly efficient multiplexed base editing tool elevates our ability of genome manipulation and combinatorial engineering in Shewanella, and may provide valuable insights in fundamental and applied research of extracellular electron transfer.
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Affiliation(s)
- Yaru Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Meijie Cheng
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Yan Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Lin Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Lixia Fang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China
| | - Yingxiu Cao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China,Corresponding author. Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China,Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072, China,Corresponding author. Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
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9
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An ADP-ribosyltransferase toxin kills bacterial cells by modifying structured non-coding RNAs. Mol Cell 2022; 82:3484-3498.e11. [PMID: 36070765 DOI: 10.1016/j.molcel.2022.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/25/2022] [Accepted: 08/11/2022] [Indexed: 11/24/2022]
Abstract
ADP-ribosyltransferases (ARTs) were among the first identified bacterial virulence factors. Canonical ART toxins are delivered into host cells where they modify essential proteins, thereby inactivating cellular processes and promoting pathogenesis. Our understanding of ARTs has since expanded beyond protein-targeting toxins to include antibiotic inactivation and DNA damage repair. Here, we report the discovery of RhsP2 as an ART toxin delivered between competing bacteria by a type VI secretion system of Pseudomonas aeruginosa. A structure of RhsP2 reveals that it resembles protein-targeting ARTs such as diphtheria toxin. Remarkably, however, RhsP2 ADP-ribosylates 2'-hydroxyl groups of double-stranded RNA, and thus, its activity is highly promiscuous with identified cellular targets including the tRNA pool and the RNA-processing ribozyme, ribonuclease P. Consequently, cell death arises from the inhibition of translation and disruption of tRNA processing. Overall, our data demonstrate a previously undescribed mechanism of bacterial antagonism and uncover an unprecedented activity catalyzed by ART enzymes.
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10
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Structural and mechanistic basis for recognition of alternative tRNA precursor substrates by bacterial ribonuclease P. Nat Commun 2022; 13:5120. [PMID: 36045135 PMCID: PMC9433436 DOI: 10.1038/s41467-022-32843-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/19/2022] [Indexed: 11/25/2022] Open
Abstract
Binding of precursor tRNAs (ptRNAs) by bacterial ribonuclease P (RNase P) involves an encounter complex (ES) that isomerizes to a catalytic conformation (ES*). However, the structures of intermediates and the conformational changes that occur during binding are poorly understood. Here, we show that pairing between the 5′ leader and 3′RCCA extending the acceptor stem of ptRNA inhibits ES* formation. Cryo-electron microscopy single particle analysis reveals a dynamic enzyme that becomes ordered upon formation of ES* in which extended acceptor stem pairing is unwound. Comparisons of structures with alternative ptRNAs reveals that once unwinding is completed RNase P primarily uses stacking interactions and shape complementarity to accommodate alternative sequences at its cleavage site. Our study reveals active site interactions and conformational changes that drive molecular recognition by RNase P and lays the foundation for understanding how binding interactions are linked to helix unwinding and catalysis. Ribonuclease P efficiently processes all tRNA precursors despite sequence variation at the site of cleavage. Here, authors use high-throughput enzymology and cryoEM to reveal conformational changes that drive recognition by bacterial RNase P.
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11
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Mohanty BK, Nichols K, Kushner SR. Maturation of the E. coli Glu2, Ile1 and Ala1B tRNAs utilizes a complex processing pathway. Mol Microbiol 2022; 118:30-46. [PMID: 35652235 DOI: 10.1111/mmi.14949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 11/29/2022]
Abstract
Despite significant progress in understanding the diversity of tRNA processing pathways in Escherichia coli, the mechanism for the maturation of tRNAs encoded within the rRNA operons has not received much attention. Here we show that the Glu2, Ile1 and Ala1B tRNAs, encoded by 10 genes located between the 16S and 23S rRNAs in the seven rRNA operons, are matured via a RNase E-independent processing pathway that utilizes at least six different enzymes. It has been shown that the Glu2 and Ile1-Ala1B pre-tRNAs released by initial RNase III cleavages of the 30S primary rRNA transcripts retain extended 5'-leader (35-139 nt) and 3'-trailer (166-185 nt) sequences. However, the 5' maturation of the tRNAs by RNase P is inhibited until the trailer sequences are shortened to 1-4 nucleotides, initially by a second RNase III cleavage at 31-42 nucleotides downstream of the CCA determinant followed by exonucleolytic trimming. The RNase III cleaved Glu2 and Ile1-Ala1B trailer fragments are degraded via PAP I- dependent exonucleolytic decay. Compared to the six previously characterized tRNA processing pathways, maturation of the Glu2, Ile1, and Ala1B tRNAs is considerably more complex and appears to be distinct from what occurs in Gram-positive bacteria.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics and Microbiology, University of Georgia, Athens, GA, USA
| | - Keri Nichols
- Department of Genetics and Microbiology, University of Georgia, Athens, GA, USA
| | - Sidney R Kushner
- Department of Genetics and Microbiology, University of Georgia, Athens, GA, USA
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12
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Mohanty BK, Kushner SR. Regulation of mRNA decay in E. coli. Crit Rev Biochem Mol Biol 2022; 57:48-72. [PMID: 34547957 PMCID: PMC9973670 DOI: 10.1080/10409238.2021.1968784] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 08/03/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
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
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