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You J, Wang Y, Wang K, Du Y, Zhang X, Zhang X, Yang T, Pan X, Rao Z. Utilizing 5' UTR Engineering Enables Fine-Tuning of Multiple Genes within Operons to Balance Metabolic Flux in Bacillus subtilis. BIOLOGY 2024; 13:277. [PMID: 38666889 PMCID: PMC11047901 DOI: 10.3390/biology13040277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/10/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024]
Abstract
The application of synthetic biology tools to modulate gene expression to increase yield has been thoroughly demonstrated as an effective and convenient approach in industrial production. In this study, we employed a high-throughput screening strategy to identify a 5' UTR sequence from the genome of B. subtilis 168. This sequence resulted in a 5.8-fold increase in the expression level of EGFP. By utilizing the 5' UTR sequence to overexpress individual genes within the rib operon, it was determined that the genes ribD and ribAB serve as rate-limiting enzymes in the riboflavin synthesis pathway. Constructing a 5' UTR library to regulate EGFP expression resulted in a variation range in gene expression levels exceeding 100-fold. Employing the same 5' UTR library to regulate the expression of EGFP and mCherry within the operon led to a change in the expression ratio of these two genes by over 10,000-fold. So, employing a 5' UTR library to modulate the expression of the rib operon gene and construct a synthetic rib operon resulted in a 2.09-fold increase in riboflavin production. These results indicate that the 5' UTR sequence identified and characterized in this study can serve as a versatile synthetic biology toolkit for achieving complex metabolic network reconstruction. This toolkit can facilitate the fine-tuning of gene expression to produce target products.
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Affiliation(s)
- Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
| | - Yifan Wang
- Department of Food Science and Technology, Texas A & M University, College Station, TX 77843, USA;
| | - Kang Wang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Yuxuan Du
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xiaoling Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xian Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
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2
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Aseev LV, Koledinskaya LS, Boni IV. Extraribosomal Functions of Bacterial Ribosomal Proteins-An Update, 2023. Int J Mol Sci 2024; 25:2957. [PMID: 38474204 DOI: 10.3390/ijms25052957] [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: 01/19/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Ribosomal proteins (r-proteins) are abundant, highly conserved, and multifaceted cellular proteins in all domains of life. Most r-proteins have RNA-binding properties and can form protein-protein contacts. Bacterial r-proteins govern the co-transcriptional rRNA folding during ribosome assembly and participate in the formation of the ribosome functional sites, such as the mRNA-binding site, tRNA-binding sites, the peptidyl transferase center, and the protein exit tunnel. In addition to their primary role in a cell as integral components of the protein synthesis machinery, many r-proteins can function beyond the ribosome (the phenomenon known as moonlighting), acting either as individual regulatory proteins or in complexes with various cellular components. The extraribosomal activities of r-proteins have been studied over the decades. In the past decade, our understanding of r-protein functions has advanced significantly due to intensive studies on ribosomes and gene expression mechanisms not only in model bacteria like Escherichia coli or Bacillus subtilis but also in little-explored bacterial species from various phyla. The aim of this review is to update information on the multiple functions of r-proteins in bacteria.
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Affiliation(s)
- Leonid V Aseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
| | | | - Irina V Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia
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3
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Xu T, Wang J, Wu Y, Wu J, Lu W, Liu M, Zhang S, Xie D, Xin W, Xie J. Ac4C Enhances the Translation Efficiency of Vegfa mRNA and Mediates Central Sensitization in Spinal Dorsal Horn in Neuropathic Pain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303113. [PMID: 37877615 PMCID: PMC10724395 DOI: 10.1002/advs.202303113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/25/2023] [Indexed: 10/26/2023]
Abstract
N4-Acetylcytidine (ac4C), a highly conserved post-transcriptional machinery with extensive existence for RNA modification, plays versatile roles in various cellular processes and functions. However, the molecular mechanism by which ac4C modification mediates neuropathic pain remains elusive. Here, it is found that the enhanced ac4C modification promotes the recruitment of polysome in Vegfa mRNA and strengthens the translation efficiency following SNI. Nerve injury increases the expression of NAT10 and the interaction between NAT10 and Vegfa mRNA in the dorsal horn neurons, and the gain and loss of NAT10 function further confirm that NAT10 is involved in the ac4C modification in Vegfa mRNA and pain behavior. Moreover, the ac4C-mediated VEGFA upregulation contributes to the central sensitivity and neuropathic pain induced by SNI or AAV-hSyn-NAT10. Finally, SNI promotes the binding of HNRNPK in Vegfa mRNA and subsequently recruits the NAT10. The enhanced interaction between HNRNPK and NAT10 contributes to the ac4C modification of Vegfa mRNA and neuropathic pain. These findings suggest that the enhanced interaction between HNRNPK and Vegfa mRNA upregulates the ac4C level by recruiting NAT10 and contributes to the central sensitivity and neuropathic pain following SNI. Blocking this cascade may be a novel therapeutic approach in patients with neuropathic pain.
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Affiliation(s)
- Ting Xu
- Neuroscience ProgramZhongshan School of MedicineThe Fifth Affiliated HospitalGuangdong Province Key Laboratory of Brain Function and DiseaseDepartment of Physiology and Pain Research CenterSun Yat‐Sen UniversityGuangzhou510080China
| | - Jing Wang
- Neuroscience ProgramZhongshan School of MedicineThe Fifth Affiliated HospitalGuangdong Province Key Laboratory of Brain Function and DiseaseDepartment of Physiology and Pain Research CenterSun Yat‐Sen UniversityGuangzhou510080China
- Department of Pain ManagementHenan Provincial People's HospitalZhengzhou UniversityZhengzhou450000China
| | - Yan Wu
- Department of AnesthesiologyThe First Affiliated Hospital of Sun Yat‐Sen UniversityGuangzhouGuangdong510062China
| | - Jia‐Yan Wu
- Neuroscience ProgramZhongshan School of MedicineThe Fifth Affiliated HospitalGuangdong Province Key Laboratory of Brain Function and DiseaseDepartment of Physiology and Pain Research CenterSun Yat‐Sen UniversityGuangzhou510080China
| | - Wei‐Cheng Lu
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation for Cancer MedicineSun Yat‐Sen University Cancer CenterGuangzhou510060China
| | - Meng Liu
- Department of Anesthesia and Pain MedicineGuangzhou First People's HospitalGuangzhou510180China
| | - Su‐Bo Zhang
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation for Cancer MedicineSun Yat‐Sen University Cancer CenterGuangzhou510060China
| | - Dan Xie
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation for Cancer MedicineSun Yat‐Sen University Cancer CenterGuangzhou510060China
| | - Wen‐Jun Xin
- Neuroscience ProgramZhongshan School of MedicineThe Fifth Affiliated HospitalGuangdong Province Key Laboratory of Brain Function and DiseaseDepartment of Physiology and Pain Research CenterSun Yat‐Sen UniversityGuangzhou510080China
| | - Jing‐Dun Xie
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation for Cancer MedicineSun Yat‐Sen University Cancer CenterGuangzhou510060China
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4
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Sato K, Takayama KI, Inoue S. Stress granules sequester Alzheimer's disease-associated gene transcripts and regulate disease-related neuronal proteostasis. Aging (Albany NY) 2023; 15:204737. [PMID: 37219408 DOI: 10.18632/aging.204737] [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: 03/24/2023] [Accepted: 04/28/2023] [Indexed: 05/24/2023]
Abstract
Environmental and physiological stresses can accelerate Alzheimer's disease (AD) pathogenesis. Under stress, a cytoplasmic membraneless structure termed a stress granule (SG) is formed and is associated with various neurodegenerative disorders, including AD. SGs contain translationally arrested mRNAs, suggesting that impaired RNA metabolism in neurons causes AD progression; however, the underlying mechanism remains unclear. Here, we identified numerous mRNAs and long non-coding RNAs that are directly targeted by the SG core proteins G3BP1 and G3BP2. They redundantly target RNAs before and after stress conditions. We further identified RNAs within SGs, wherein AD-associated gene transcripts accumulated, suggesting that SGs can directly regulate AD development. Furthermore, gene-network analysis revealed a possible link between the sequestration of RNAs by SGs and the impairment of protein neurohomeostasis in AD brains. Together, our study provides a comprehensive RNA regulatory mechanism involving SGs, which could be targeted therapeutically to slow AD progression mediated by SGs.
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Affiliation(s)
- Kaoru Sato
- Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology (TMIG), Itabashi-ku, Tokyo 173-0015, Japan
- Integrated Research Initiative for Living Well with Dementia (IRIDE), TMIG, Itabashi-ku, Tokyo 173-0015, Japan
| | - Ken-Ichi Takayama
- Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology (TMIG), Itabashi-ku, Tokyo 173-0015, Japan
| | - Satoshi Inoue
- Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology (TMIG), Itabashi-ku, Tokyo 173-0015, Japan
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5
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Wei M, Wu J, Sun H, Zhang B, Hu X, Wang Q, Li B, Xu L, Ma T, Gao J, Li F, Ling D. An Enzymatic Antibiotic Adjuvant Modulates the Infectious Microenvironment to Overcome Antimicrobial Resistance of Pathogens. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205471. [PMID: 36399641 DOI: 10.1002/smll.202205471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/24/2022] [Indexed: 06/16/2023]
Abstract
The emergence and evolution of antimicrobial resistance (AMR) pose a significant challenge to the current arsenal to fight infection. Antibiotic adjuvants represent an appealing tactic for tackling the AMR of pathogens, however, their practical applications are greatly constrained by the harsh infectious microenvironment. Herein, it is found that silver nanoclusters (Ag NCs) can possess tunable enzymatic activities to modulate infectious microenvironments. Based on this finding, an enzymatic nanoadjuvant (EnzNA) self-assembled from Ag NCs, which is inert under neutral physiological conditions but can readily disassemble into isolated Ag NCs exhibiting biofilm destructive oxidase-mimetic activity in the acidic biofilm microenvironment, is developed. Once internalized into the neutral cytoplasm of bacteria, Ag NCs switch to reveal the thiol oxidase-mimetic activity to suppress ribosomal biogenesis for AMR reversal and evolution inhibition of pathogens. Consequently, EnzNAs revitalize various existing antibiotics against methicillin-resistant Staphylococcus aureus, and potentiate the antibiotic efficacy against biofilm-mediated skin infection and lethal lung infection in mice. These findings highlight the capability of enzyme-mimetic nanomaterials to modulate the infectious microenvironment and potentiate antibiotics, providing a paradigm shift for anti-infection therapy.
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Affiliation(s)
- Min Wei
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jiahe Wu
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006, China
| | - Heng Sun
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Bo Zhang
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
- WLA Laboratories, Shanghai, 201203, China
| | - Xi Hu
- Department of Clinical Pharmacy, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Qiyue Wang
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Bowen Li
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lilan Xu
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Teng Ma
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jianqing Gao
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
- Cancer Center of Zhejiang University, Zhejiang University, Hangzhou, 310058, China
| | - Fangyuan Li
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Daishun Ling
- Institute of Pharmaceutics, Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
- Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
- WLA Laboratories, Shanghai, 201203, China
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6
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Zabed HM, Akter S, Rupani PF, Akor J, Zhang Y, Zhao M, Zhang C, Ragauskas AJ, Qi X. Biocatalytic gateway to convert glycerol into 3-hydroxypropionic acid in waste-based biorefineries: Fundamentals, limitations, and potential research strategies. Biotechnol Adv 2023; 62:108075. [PMID: 36502965 DOI: 10.1016/j.biotechadv.2022.108075] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/02/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022]
Abstract
Microbial conversion of bioenergy-derived waste glycerol into value-added chemicals has emerged as an important bioprocessing technology due to its eco-friendliness, feasible technoeconomics, and potential to provide sustainability in biodiesel and bioethanol production. Glycerol is an abundant liquid waste from bioenergy plants with a projected volume of 6 million tons by 2025, accounting for about 10% of biodiesel and 2.5% of bioethanol yields. 3-Hydroxypropionic acid (3-HP) is a major product of glycerol bioconversion, which is the third largest biobased platform compound with expected market size and value of 3.6 million tons/year and USD 10 billion/year, respectively. Despite these biorefinery values, 3-HP biosynthesis from glycerol is still at an immature stage of commercial exploitation. The main challenges behind this immaturity are the toxic effects of 3-HPA on cells, the distribution of carbon flux to undesirable pathways, low tolerance of cells to glycerol and 3-HP, co-factor dependence of enzymes, low enzyme activity and stability, and the problems of substrate inhibition and specificity of enzymes. To address these challenges, it is necessary to understand the fundamentals of glycerol bioconversion and 3-HP production in terms of metabolic pathways, related enzymes, cell factories, midstream process configurations, and downstream 3-HP recovery, as discussed in this review critically and comprehensively. It is equally important to know the current challenges and limitations in 3-HP production, which are discussed in detail along with recent research efforts and remaining gaps. Finally, possible research strategies are outlined considering the recent technological advances in microbial biosynthesis, aiming to attract further research efforts to achieve a sustainable and industrially exploitable 3-HP production technology. By discussing the use of advanced tools and strategies to overcome the existing challenges in 3-HP biosynthesis, this review will attract researchers from many other similar biosynthesis technologies and provide a common gateway for their further development.
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Affiliation(s)
- Hossain M Zabed
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Suely Akter
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Parveen Fatemah Rupani
- Department of Chemical Engineering, Ku Luven, Jan De Nayerlaan 5, 2860 Sint-Katelijne-Waver, Belgium
| | - Joseph Akor
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Yufei Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Mei Zhao
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Cunsheng Zhang
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN 37996, USA; Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, The University of Tennessee Institute of Agriculture, Knoxville, TN 37996, USA; UTK-ORNL Joint Institute for Biological Science, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Xianghui Qi
- School of Food & Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China; School of Life Sciences, Guangzhou University, Guangzhou 510,006, Guangdong Province, China.
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7
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Binding of 30S Ribosome Induces Single-stranded Conformation Within and Downstream of the Expression Platform in a Translational Riboswitch. J Mol Biol 2022; 434:167668. [PMID: 35667471 DOI: 10.1016/j.jmb.2022.167668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/29/2022] [Accepted: 05/31/2022] [Indexed: 11/23/2022]
Abstract
Translational riboswitches are bacterial gene regulatory elements found in the 5'-untranslated region of mRNAs. They operate through a conformational refolding reaction that is triggered by a concentration change of a modulating small molecular ligand. The translation initiation region (TIR) is either released from or incorporated into base pairing interactions through the conformational switch. Hence, initiation of translation is regulated by the accessibility of the Shine-Dalgarno sequence and start codon. Interaction with the 30S ribosome is indispensable for the structural switch between functional OFF and ON states. However, on a molecular level it is still not fully resolved how the ribosome is accommodated near or at the translation initiation region in the context of translational riboswitches. The standby model of translation initiation postulates a binding site where the mRNA enters the ribosome and where it resides until the initiation site becomes unstructured and accessible. We here investigated the adenine-sensing riboswitch from Vibrio vulnificus. By application of a 19F labelling strategy for NMR spectroscopy that utilizes ligation techniques to synthesize differentially 19F labelled riboswitch molecules we show that nucleotides directly downstream of the riboswitch domain are first involved in productive interaction with the 30S ribosomal subunit. Upon the concerted action of ligand and the ribosomal protein rS1 the TIR becomes available and subsequently the 30S ribosome can slide towards the TIR. It will be interesting to see whether this is a general feature in translational riboswitches or if riboswitches exist where this region is structured and represent yet another layer of regulation.
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8
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Ma C, Wang S, Cao Y, Tang W, Wuniqiemu T, Teng F, Zhu X, Wei Y, Dong J. Screening and Verification of Differentially Expressed Long Non-coding RNAs in the Peripheral Blood of Patients With asthma. Front Pharmacol 2022; 13:834009. [PMID: 35273507 PMCID: PMC8902465 DOI: 10.3389/fphar.2022.834009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
Growing evidence suggests that long non-coding RNAs (lncRNAs) play a key role in the pathogenesis of asthma. Although some differentially expressed lncRNAs have been identified in asthmatic patients, many asthma-related lncRNAs have not been annotated. In the present study, six patients and three healthy subjects were randomly selected from 34 asthmatic patients and 17 healthy subjects. Second-generation high-throughput sequencing was performed on their peripheral blood samples. There were 1,137 differentially expressed lncRNAs in the asthma patients compared to in the healthy controls, of which 485 were upregulated and 652 were downregulated. The top 30 enriched GO and KEGG terms were identified, and the cytosolic ribosome (GO:0022626) and ribosome (hsa03010) were associated with the most differentially expressed lncRNAs. The top 10 differentially expressed lncRNAs associated with asthma were verified by an lncRNA-mRNA co-expression network and RT-qPCR. Seven of the these (NONHSAT015495.2, MSTRG.71212.2, NONHSAT163272.1, NONHSAT181891.1, NONHSAT190964.1, ENST00000564809, and NONHSAT076890.2) were down-regulated in the peripheral blood of asthmatic patients, which was consistent with the sequencing results. Three patients and three healthy subjects were randomly selected from the remaining subjects to verify these seven lncRNAs by RT-qPCR, which further confirmed the sequencing results. Public database GSE106230 was also in agreement with the FPKM (Fragments Per kilobase of exon model per Million mapped reads) trends of ENST00000564809, NONHSAT015495.2, NONHSAT181891.1, and NONHSAT190964.1. In conclusion, the present study identified seven lncRNAs that may serve as potential biological markers for asthma.
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Affiliation(s)
- Cheng Ma
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Shiyuan Wang
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Yuxue Cao
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Weifeng Tang
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Tulake Wuniqiemu
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Fangzhou Teng
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Xueyi Zhu
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Ying Wei
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
| | - Jingcheng Dong
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, China.,Institutes of Integrative Medicine, Fudan University, Shanghai, China
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9
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Sun M, Gao AX, Li A, Liu X, Wang R, Yang Y, Li Y, Liu C, Bai Z. Bicistronic design as recombinant expression enhancer: characteristics, applications, and structural optimization. Appl Microbiol Biotechnol 2021; 105:7709-7720. [PMID: 34596722 DOI: 10.1007/s00253-021-11611-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/16/2021] [Accepted: 09/18/2021] [Indexed: 11/30/2022]
Abstract
The bicistronic design (BCD) is characterized by a short fore-cistron sequence and a second Shine-Dalgarno (SD2) sequence upstream of the target gene. The outstanding performance of this expression cassette in promoting recombinant protein production has attracted attention. Recently, the application of the BCD has been further extended to gene expression control, protein translation monitoring, and membrane protein production. In this review, we summarize the characteristics, molecular mechanisms, applications, and structural optimization of the BCD expression cassette. We also specifically discuss the challenges that the BCD system still faces. This is the first review of the BCD expression strategy, and it is believed that an in-depth understanding of the BCD will help researchers to better utilize and develop it. KEY POINTS: • Summary of the characteristics and molecular mechanisms of the BCD system. • Review of the actual applications of the BCD expression cassette. • Summary of the structural optimization of the BCD system.
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Affiliation(s)
- Manman Sun
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Alex Xiong Gao
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - An Li
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Xiuxia Liu
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China. .,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China.
| | - Rongbing Wang
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Yankun Yang
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Ye Li
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Chunli Liu
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Zhonghu Bai
- National Engineering Laboratory of Cereal Fermentation Technology, Jiangnan University, Wuxi, 214112, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China. .,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China.
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10
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Basu P, Altuvia S. RelA binding of mRNAs modulates translation or sRNA-mRNA basepairing depending on the position of the GGAG site. Mol Microbiol 2021; 117:143-159. [PMID: 34523176 DOI: 10.1111/mmi.14812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/12/2021] [Accepted: 09/12/2021] [Indexed: 11/26/2022]
Abstract
Previously, we reported that RelA protein facilitates Hfq-mediated mRNA-sRNA regulation by binding sRNAs carrying a Shine-Dalgarno-like GGAG sequence. In turn, sRNA-Hfq monomers are stabilized, enabling the attachment of more Hfq subunits to form a functional hexamer. Here, using CLIP-seq, we present a global analysis of RelA-bound RNAs showing that RelA interacts with sRNAs as well as with mRNAs carrying a GGAG motif. RelA binding of mRNAs carrying GGAG at position -7 relative to the initiation codon (AUG) inhibits translation by interfering with the binding of 30S ribosomes. The extent of inhibition depends on the distance of GGAG relative to the AUG, as shortening the spacing between GGAG and AUG abrogates RelA-mediated inhibition. Interestingly, RelA binding of target mRNAs carrying GGAG in the coding sequence or close to AUG facilitates target gene regulation by sRNA partners that lack GGAG. However, translation inhibition caused by RelA binding of mRNAs carrying GGAG at position -7 relative to the AUG renders sRNA-mRNA basepairing regulation ineffective. Our study indicates that by binding RNAs carrying GGAG the ribosome-associated RelA protein inhibits translation of specific newly synthesized incoming mRNAs or enables basepairing regulation by their respective sRNA partners, thereby introducing a new regulatory concept for the bacterial response.
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Affiliation(s)
- Pallabi Basu
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Shoshy Altuvia
- Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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11
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Aseev LV, Koledinskaya LS, Bychenko OS, Boni IV. Regulation of Ribosomal Protein Synthesis in Mycobacteria: The Autogenous Control of rpsO. Int J Mol Sci 2021; 22:9679. [PMID: 34575857 PMCID: PMC8470358 DOI: 10.3390/ijms22189679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 01/23/2023] Open
Abstract
The autogenous regulation of ribosomal protein (r-protein) synthesis plays a key role in maintaining the stoichiometry of ribosomal components in bacteria. In this work, taking the rpsO gene as a classic example, we addressed for the first time the in vivo regulation of r-protein synthesis in the mycobacteria M. smegmatis (Msm) and M. tuberculosis (Mtb). We used a strategy based on chromosomally integrated reporters under the control of the rpsO regulatory regions and the ectopic expression of Msm S15 to measure its impact on the reporter expression. Because the use of E. coli as a host appeared inefficient, a fluorescent reporter system was developed by inserting Msm or Mtb rpsO-egfp fusions into the Msm chromosome and expressing Msm S15 or E. coli S15 in trans from a novel replicative shuttle vector, pAMYC. The results of the eGFP expression measurements in Msm cells provided evidence that the rpsO gene in Msm and Mtb was feedback-regulated at the translation level. The mutagenic analysis showed that the folding of Msm rpsO 5'UTR in a pseudoknot appeared crucial for repression by both Msm S15 and E. coli S15, thus indicating a striking resemblance of the rpsO feedback control in mycobacteria and in E. coli.
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Affiliation(s)
| | | | | | - Irina V. Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (L.V.A.); (L.S.K.); (O.S.B.)
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12
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Switching at the ribosome: riboswitches need rProteins as modulators to regulate translation. Nat Commun 2021; 12:4723. [PMID: 34354064 PMCID: PMC8342710 DOI: 10.1038/s41467-021-25024-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/17/2021] [Indexed: 11/29/2022] Open
Abstract
Translational riboswitches are cis-acting RNA regulators that modulate the expression of genes during translation initiation. Their mechanism is considered as an RNA-only gene-regulatory system inducing a ligand-dependent shift of the population of functional ON- and OFF-states. The interaction of riboswitches with the translation machinery remained unexplored. For the adenine-sensing riboswitch from Vibrio vulnificus we show that ligand binding alone is not sufficient for switching to a translational ON-state but the interaction of the riboswitch with the 30S ribosome is indispensable. Only the synergy of binding of adenine and of 30S ribosome, in particular protein rS1, induces complete opening of the translation initiation region. Our investigation thus unravels the intricate dynamic network involving RNA regulator, ligand inducer and ribosome protein modulator during translation initiation. Translational regulation by riboswitches is an important mechanism for the modulation of gene expression in bacteria. Here the authors show that the ligand-induced allosteric switch in the adenine-sensing riboswitch from V. vulnificus is insufficient and leads only to a partial opening of the ribosome binding site and requires interaction with 30S-bound ribosomal protein S1, which acts as an RNA chaperone.
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13
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Mikhaylina AO, Nikonova EY, Kostareva OS, Tishchenko SV. Regulation of Ribosomal Protein Synthesis in Prokaryotes. Mol Biol 2021. [DOI: 10.1134/s0026893321010118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Orthogonal translation enables heterologous ribosome engineering in E. coli. Nat Commun 2021; 12:599. [PMID: 33500394 PMCID: PMC7838251 DOI: 10.1038/s41467-020-20759-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 12/16/2020] [Indexed: 01/30/2023] Open
Abstract
The ribosome represents a promising avenue for synthetic biology, but its complexity and essentiality have hindered significant engineering efforts. Heterologous ribosomes, comprising rRNAs and r-proteins derived from different microorganisms, may offer opportunities for novel translational functions. Such heterologous ribosomes have previously been evaluated in E. coli via complementation of a genomic ribosome deficiency, but this method fails to guide the engineering of refractory ribosomes. Here, we implement orthogonal ribosome binding site (RBS):antiRBS pairs, in which engineered ribosomes are directed to researcher-defined transcripts, to inform requirements for heterologous ribosome functionality. We discover that optimized rRNA processing and supplementation with cognate r-proteins enhances heterologous ribosome function for rRNAs derived from organisms with ≥76.1% 16S rRNA identity to E. coli. Additionally, some heterologous ribosomes undergo reduced subunit exchange with E. coli-derived subunits. Cumulatively, this work provides a general framework for heterologous ribosome engineering in living cells.
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15
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Reis AC, Salis HM. An Automated Model Test System for Systematic Development and Improvement of Gene Expression Models. ACS Synth Biol 2020; 9:3145-3156. [PMID: 33054181 DOI: 10.1021/acssynbio.0c00394] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Gene expression models greatly accelerate the engineering of synthetic metabolic pathways and genetic circuits by predicting sequence-function relationships and reducing trial-and-error experimentation. However, developing models with more accurate predictions remains a significant challenge. Here we present a model test system that combines advanced statistics, machine learning, and a database of 9862 characterized genetic systems to automatically quantify model accuracies, accept or reject mechanistic hypotheses, and identify areas for model improvement. We also introduce model capacity, a new information theoretic metric for correct cross-data-set comparisons. We demonstrate the model test system by comparing six models of translation initiation rate, evaluating 100 mechanistic hypotheses, and uncovering new sequence determinants that control protein expression levels. We then applied these results to develop a biophysical model of translation initiation rate with significant improvements in accuracy. Automated model test systems will dramatically accelerate the development of gene expression models, and thereby transition synthetic biology into a mature engineering discipline.
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16
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A Novel Platform Using RNA Signatures To Accelerate Antimicrobial Susceptibility Testing in Neisseria gonorrhoeae. J Clin Microbiol 2020; 58:JCM.01152-20. [PMID: 32967905 DOI: 10.1128/jcm.01152-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/09/2020] [Indexed: 12/27/2022] Open
Abstract
The rise of antimicrobial-resistant pathogens can be attributed to the lack of a rapid pathogen identification (ID) or antimicrobial susceptibility testing (AST), resulting in delayed therapeutic decisions at the point of care. Gonorrhea is usually empirically treated, with no AST results available before treatment, thus contributing to the rapid rise in drug resistance. Here, we present a rapid AST platform using RNA signatures for Neisseria gonorrhoeae Transcriptome sequencing (RNA-seq) followed by bioinformatic tools was applied to explore potential markers in the transcriptome profile of N. gonorrhoeae upon minutes of azithromycin exposure. Validation of candidate markers using quantitative real-time PCR (qRT-PCR) showed that two markers (arsR [NGO1562] and rpsO) can deliver accurate AST results across 14 tested isolates. Further validation of our susceptibility threshold in comparison to MIC across 64 more isolates confirmed the reliability of our platform. Our RNA markers combined with emerging molecular point-of-care systems has the potential to greatly accelerate both ID and AST to inform treatment.
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17
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Watson ZL, Ward FR, Méheust R, Ad O, Schepartz A, Banfield JF, Cate JH. Structure of the bacterial ribosome at 2 Å resolution. eLife 2020; 9:60482. [PMID: 32924932 DOI: 10.1101/2020.06.26.174334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/11/2020] [Indexed: 05/24/2023] Open
Abstract
Using cryo-electron microscopy (cryo-EM), we determined the structure of the Escherichia coli 70S ribosome with a global resolution of 2.0 Å. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and models of the bacterial ribosome presented here now allow a deeper phylogenetic analysis of ribosomal components including structural conservation to the level of solvation. The high quality of the maps should enable future structural analyses of the chemical basis for translation and aid the development of robust tools for cryo-EM structure modeling and refinement.
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Affiliation(s)
- Zoe L Watson
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Fred R Ward
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Raphaël Méheust
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States
- Earth and Planetary Science, University of California, Berkeley, Berkeley, United States
| | - Omer Ad
- Department of Chemistry, Yale University, New Haven, United States
| | - Alanna Schepartz
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, United States
- Earth and Planetary Science, University of California, Berkeley, Berkeley, United States
- Environmental Science, Policy and Management, University of California Berkeley, Berkeley, United States
| | - Jamie Hd Cate
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
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18
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Watson ZL, Ward FR, Méheust R, Ad O, Schepartz A, Banfield JF, Cate JHD. Structure of the bacterial ribosome at 2 Å resolution. eLife 2020; 9:e60482. [PMID: 32924932 PMCID: PMC7550191 DOI: 10.7554/elife.60482] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/11/2020] [Indexed: 12/31/2022] Open
Abstract
Using cryo-electron microscopy (cryo-EM), we determined the structure of the Escherichia coli 70S ribosome with a global resolution of 2.0 Å. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and models of the bacterial ribosome presented here now allow a deeper phylogenetic analysis of ribosomal components including structural conservation to the level of solvation. The high quality of the maps should enable future structural analyses of the chemical basis for translation and aid the development of robust tools for cryo-EM structure modeling and refinement.
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Affiliation(s)
- Zoe L Watson
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - Fred R Ward
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Raphaël Méheust
- Innovative Genomics Institute, University of California, BerkeleyBerkeleyUnited States
- Earth and Planetary Science, University of California, BerkeleyBerkeleyUnited States
| | - Omer Ad
- Department of Chemistry, Yale UniversityNew HavenUnited States
| | - Alanna Schepartz
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, BerkeleyBerkeleyUnited States
- Earth and Planetary Science, University of California, BerkeleyBerkeleyUnited States
- Environmental Science, Policy and Management, University of California BerkeleyBerkeleyUnited States
| | - Jamie HD Cate
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
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19
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Abstract
Many organisms, including bacteria, code for multiple paralogues of some ribosomal protein subunits. The relative contribution of these alternative subunits to ribosome function and protein synthesis is unknown and controversial. Many studies on alternative ribosomes have been confounded by isolation of alternative and canonical ribosomes from different strains or growth conditions, potentially confounding results. Here, we show that one form of alternative ribosome from Mycobacterium smegmatis has a distinct translational profile compared with canonical ribosomes purified from an identical cellular context. We also identify a role for alternative ribosomes in iron homeostasis. Given the prevalence of alternative ribosomal genes in diverse organisms, our study suggests that alternative ribosomes may represent a further layer of regulation of gene translation. Alternative ribosome subunit proteins are prevalent in the genomes of diverse bacterial species, but their functional significance is controversial. Attempts to study microbial ribosomal heterogeneity have mostly relied on comparing wild-type strains with mutants in which subunits have been deleted, but this approach does not allow direct comparison of alternate ribosome isoforms isolated from identical cellular contexts. Here, by simultaneously purifying canonical and alternative RpsR ribosomes from Mycobacterium smegmatis, we show that alternative ribosomes have distinct translational features compared with their canonical counterparts. Both alternative and canonical ribosomes actively take part in protein synthesis, although they translate a subset of genes with differential efficiency as measured by ribosome profiling. We also show that alternative ribosomes have a relative defect in initiation complex formation. Furthermore, a strain of M. smegmatis in which the alternative ribosome protein operon is deleted grows poorly in iron-depleted medium, uncovering a role for alternative ribosomes in iron homeostasis. Our work confirms the distinct and nonredundant contribution of alternative bacterial ribosomes for adaptation to hostile environments.
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20
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Azam MS, Vanderpool CK. Translation inhibition from a distance: The small RNA SgrS silences a ribosomal protein S1-dependent enhancer. Mol Microbiol 2020; 114:391-408. [PMID: 32291821 DOI: 10.1111/mmi.14514] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 12/26/2022]
Abstract
Many bacterial small RNAs (sRNAs) efficiently inhibit translation of target mRNAs by forming a duplex that sequesters the Shine-Dalgarno (SD) sequence or start codon and prevents formation of the translation initiation complex. There are a growing number of examples of sRNA-mRNA binding interactions distant from the SD region, but how these mediate translational regulation remains unclear. Our previous work in Escherichia coli and Salmonella identified a mechanism of translational repression of manY mRNA by the sRNA SgrS through a binding interaction upstream of the manY SD. Here, we report that SgrS forms a duplex with a uridine-rich translation-enhancing element in the manY 5' untranslated region. Notably, we show that the enhancer is ribosome-dependent and that the small ribosomal subunit protein S1 interacts with the enhancer to promote translation of manY. In collaboration with the chaperone protein Hfq, SgrS interferes with the interaction between the translation enhancer and ribosomal protein S1 to repress translation of manY mRNA. Since bacterial translation is often modulated by enhancer-like elements upstream of the SD, sRNA-mediated enhancer silencing could be a common mode of gene regulation.
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Affiliation(s)
- Muhammad S Azam
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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21
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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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22
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Sterk M, Romilly C, Wagner EGH. Unstructured 5'-tails act through ribosome standby to override inhibitory structure at ribosome binding sites. Nucleic Acids Res 2019; 46:4188-4199. [PMID: 29420821 PMCID: PMC5934652 DOI: 10.1093/nar/gky073] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/26/2018] [Indexed: 11/13/2022] Open
Abstract
Initiation is the rate-limiting step in translation. It is well-known that stable structure at a ribosome binding site (RBS) impedes initiation. The ribosome standby model of de Smit and van Duin, based on studies of the MS2 phage coat cistron, proposed how high translation rates can be reconciled with stable, inhibitory structures at an RBS. Here, we revisited the coat protein system and assessed the translation efficiency from its sequestered RBS by introducing standby mutations. Further experiments with gfp reporter constructs assessed the effects of 5′-tails—as standby sites—with respect to length and sequence contributions. In particular, combining in vivo and in vitro assays, we can show that tails of CA-dinucleotide repeats—and to a lesser extent, AU-repeats—dramatically increase translation rates. Tails of increasing length reach maximal rate-enhancing effects at 16–18 nucleotides. These standby tails are single-stranded and do not exert their effect by structure changes in the neighboring RBS stem–loop. In vitro translation and toeprinting assays furthermore demonstrate that standby effects are exerted at the level of translation initiation. Finally, as expected, destabilizing mutations within the coat RBS indicate an interplay with the effects of standby tails.
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Affiliation(s)
- Maaike Sterk
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, S-75124 Uppsala, Sweden
| | - Cédric Romilly
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, S-75124 Uppsala, Sweden
| | - E Gerhart H Wagner
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, S-75124 Uppsala, Sweden
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23
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The ribosomal protein S1-dependent standby site in tisB mRNA consists of a single-stranded region and a 5' structure element. Proc Natl Acad Sci U S A 2019; 116:15901-15906. [PMID: 31320593 PMCID: PMC6690012 DOI: 10.1073/pnas.1904309116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ribosome standby is a mechanism that allows translation initiation at ribosome-binding sites that display stable, inhibitory structures. It involves initiator-tRNA-independent 30S subunit binding to single-stranded RNA regions, and the subsequent relocation to the sequestered ribosome-binding sites (RBS). Direct evidence for 30S preloading had previously been elusive. We report here on a detailed characterization of the standby site in tisB mRNA. 30S subunits bind to a single-stranded region and a 5′-stem-loop structure, as shown by fluorescence anisotropy experiments and footprint mapping by cross-linking–immunoprecipitation experiments. Ribosomal protein S1, on its own and in the context of the 30S ribosome, binds to the standby site. This is required for standby-dependent translation, likely reflecting S1-dependent directional unfolding over more than ≈100 nt to reach the sequestered RBS. In bacteria, stable RNA structures that sequester ribosome-binding sites (RBS) impair translation initiation, and thus protein output. In some cases, ribosome standby can overcome inhibition by structure: 30S subunits bind sequence-nonspecifically to a single-stranded region and, on breathing of the inhibitory structure, relocate to the RBS for initiation. Standby can occur over long distances, as in the active, +42 tisB mRNA, encoding a toxin. This mRNA is translationally silenced by an antitoxin sRNA, IstR-1, that base pairs to the standby site. In tisB and other cases, a direct interaction between 30S subunits and a standby site has remained elusive. Based on fluorescence anisotropy experiments, ribosome toeprinting results, in vitro translation assays, and cross-linking–immunoprecipitation (CLIP) in vitro, carried out on standby-proficient and standby-deficient tisB mRNAs, we provide a thorough characterization of the tisB standby site. 30S subunits and ribosomal protein S1 alone display high-affinity binding to standby-competent fluorescein-labeled +42 mRNA, but not to mRNAs that lack functional standby sites. Ribosomal protein S1 is essential for standby, as 30∆S1 subunits do not support standby-dependent toeprints and TisB translation in vitro. S1 alone- and 30S-CLIP followed by RNA-seq mapping shows that the functional tisB standby site consists of the expected single-stranded region, but surprisingly, also a 5′-end stem-loop structure. Removal of the latter by 5′-truncations, or disruption of the stem, abolishes 30S binding and standby activity. Based on the CLIP-read mapping, the long-distance standby effect in +42 tisB mRNA (∼100 nt) is tentatively explained by S1-dependent directional unfolding toward the downstream RBS.
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24
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Two Old Dogs, One New Trick: A Review of RNA Polymerase and Ribosome Interactions during Transcription-Translation Coupling. Int J Mol Sci 2019; 20:ijms20102595. [PMID: 31137816 PMCID: PMC6566652 DOI: 10.3390/ijms20102595] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 12/14/2022] Open
Abstract
The coupling of transcription and translation is more than mere translation of an mRNA that is still being transcribed. The discovery of physical interactions between RNA polymerase and ribosomes has spurred renewed interest into this long-standing paradigm of bacterial molecular biology. Here, we provide a concise presentation of recent insights gained from super-resolution microscopy, biochemical, and structural work, including cryo-EM studies. Based on the presented data, we put forward a dynamic model for the interaction between RNA polymerase and ribosomes, in which the interactions are repeatedly formed and broken. Furthermore, we propose that long intervening nascent RNA will loop out and away during the forming the interactions between the RNA polymerase and ribosomes. By comparing the effect of the direct interactions between RNA polymerase and ribosomes with those that transcription factors NusG and RfaH mediate, we submit that two distinct modes of coupling exist: Factor-free and factor-mediated coupling. Finally, we provide a possible framework for transcription-translation coupling and elude to some open questions in the field.
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25
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Wang Z, Zhang J, Wang X, Wei D. High level expression and characterization of the recombinant immunotoxin DAB389-4D5 scFv targeting HER2/neu-positive ovarian carcinoma cells. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.01.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Adalat R, Saleem F, Bashir A, Ahmad M, Zulfiqar S, Shakoori AR. Multiple upstream start codons (AUG) in 5' untranslated region enhance translation efficiency of cry2Ac11 without helper protein. J Cell Biochem 2019; 120:2236-2250. [PMID: 30242865 DOI: 10.1002/jcb.27534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/01/2018] [Indexed: 01/24/2023]
Abstract
Cry2Ac11, a 65 kDa insecticidal protein produced by Bacillus thuringiensis, shows toxicity against dipteran and lepidopteran larvae. It is encoded by cry2Ac11 gene ( orf3), which is part of an operon comprising orf1, orf2, and orf3. Orf2, a helper protein, helps in proper folding and prevents aberrant aggregation of newly produced molecules. In this study, we have elucidated the effect of different mutations in translation initiation region (TIR), particularly the ribosomal binding site and the start codon (RBS-ATG) on cry2Ac11 gene expression without helper protein. All recombinant constructs were expressed in acrystalliferous B. thuringiensis subsp israelensis 4Q7 under the control of strong chimeric promoter cyt1AP/STAB. Of all the mutants, mut/RBS2, with two consecutive AUGs after the spacer region in TIR, exhibited 89- and 2246-fold higher transcript levels compared with 4Q7-operSalI/RBS ( cry2Ac11 operon) and 4Q7-w-RBS ( cry2Ac11 gene), respectively. The analysis of mut/RBS2 messenger RNA (mRNA) structure in the RBS-AUG region showed the presence of RBS in the single-stranded part of the moderately stable hairpin loop. The high expression efficiency of Cry2Ac11 mutant without helper protein is a cumulative and cooperative result of chimeric promoter cyt1AP/STAB-SD with the optimal context of RBS-AUG region provided by multiple AUGs and stabilizer sequence at 3' ends.
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Affiliation(s)
- Rooma Adalat
- Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan
| | - Faiza Saleem
- Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan
| | - Aftab Bashir
- Department of Biological Sciences, Forman Christian College, Lahore, Pakistan
| | - Munir Ahmad
- School of Biological Sciences, Quaid-i-Azam Campus, University of the Punjab, Lahore, Pakistan
| | - Soumble Zulfiqar
- School of Biological Sciences, Quaid-i-Azam Campus, University of the Punjab, Lahore, Pakistan
| | - Abdul Rauf Shakoori
- School of Biological Sciences, Quaid-i-Azam Campus, University of the Punjab, Lahore, Pakistan.,Department of Biochemistry, Faculty of Life Sciences, University of Central Punjab, Lahore, Pakistan
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27
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Abstract
Ribosomes are biological nanomachine that synthesise all proteins within a cell. It took decades to reveal the architecture of this essential cellular component. To understand the structure -function relationship of this nanomachine needed the utilisisation of different biochemical, biophysical and structural techniques. Structural studies combined with mutagenesis of the different ribosomal complexes comprising various RNAs and proteins enabled us to understand how this machine works inside a cell. Nowadays quite a number of ribosomal structures were published that confirmed biochemical studies on particular steps of protein synthesis by the ribosome . Four major steps were identified: initiation , elongation, termination and recycling. These steps lead us to the important question how the ribosome function can be regulated. Advances in technology for cryo electron microscopy: sample preparations, image recording, developments in algorithms for image analysis and processing significantly helped in revelation of structural details of the ribosome . We now have a library of ribosome structures from prokaryotes to eukaryotes that enable us to understand the complex mechanics of this nanomachine. As this structural library continues to grow, we gradually improve our understanding of this process and how it can be regulated and how the specific ribosomes can be stalled or activated, or completely disabled. This article provides a comprehensive overview of ribosomal structures that represent structural snapshots of the ribosome at its different functional states. Better understanding rises more particular questions that have to be addressed by determination structures of more complexes.Synopsis: Structural biology of the ribosome.
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Affiliation(s)
- Abid Javed
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK
| | - Elena V Orlova
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK.
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28
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Cambray G, Guimaraes JC, Arkin AP. Evaluation of 244,000 synthetic sequences reveals design principles to optimize translation in Escherichia coli. Nat Biotechnol 2018; 36:1005-1015. [DOI: 10.1038/nbt.4238] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 08/02/2018] [Indexed: 01/01/2023]
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29
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Mallik S, Basu S, Hait S, Kundu S. Translational regulation of ribosomal protein S15 drives characteristic patterns of protein-mRNA epistasis. Proteins 2018; 86:827-832. [PMID: 29679401 DOI: 10.1002/prot.25518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 04/17/2018] [Indexed: 01/15/2023]
Abstract
Do coding and regulatory segments of a gene co-evolve with each-other? Seeking answers to this question, here we analyze the case of Escherichia coli ribosomal protein S15, that represses its own translation by specifically binding its messenger RNA (rpsO mRNA) and stabilizing a pseudoknot structure at the upstream untranslated region, thus trapping the ribosome into an incomplete translation initiation complex. In the absence of S15, ribosomal protein S1 recognizes rpsO and promotes translation by melting this very pseudoknot. We employ a robust statistical method to detect signatures of positive epistasis between residue site pairs and find that biophysical constraints of translational regulation (S15-rpsO and S1-rpsO recognition, S15-mediated rpsO structural rearrangement, and S1-mediated melting) are strong predictors of positive epistasis. Transforming the epistatic pairs into a network, we find that signatures of two different, but interconnected regulatory cascades are imprinted in the sequence-space and can be captured in terms of two dense network modules that are sparsely connected to each other. This network topology further reflects a general principle of how functionally coupled components of biological networks are interconnected. These results depict a model case, where translational regulation drives characteristic residue-level epistasis-not only between a protein and its own mRNA but also between a protein and the mRNA of an entirely different protein.
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Affiliation(s)
- Saurav Mallik
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
| | - Sudipto Basu
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
| | - Suman Hait
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
| | - Sudip Kundu
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
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30
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Translation initiation in bacterial polysomes through ribosome loading on a standby site on a highly translated mRNA. Proc Natl Acad Sci U S A 2018; 115:4411-4416. [PMID: 29632209 PMCID: PMC5924895 DOI: 10.1073/pnas.1718029115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polysomes are ensembles of two or more consecutive ribosomes that translate mRNA into proteins. Adjacent ribosomes can affect the frequency with which a new ribosome is loaded into the polysome. Here we show that mRNA with a long 5′UTR can recruit the next ribosome when the genuine start site is still occupied by the leading ribosome. The second ribosome binds to the upstream standby site on the mRNA, helped by the ribosomal proteins S1/S2 of the preceding ribosome. When the translating ribosome has cleared the start codon, the consecutive ribosome can rapidly move to the translation start. Recruitment to the standby site is a mechanism to increase polysome density and to regulate the efficiency of translation in polysomes. During translation, consecutive ribosomes load on an mRNA and form a polysome. The first ribosome binds to a single-stranded mRNA region and moves toward the start codon, unwinding potential mRNA structures on the way. In contrast, the following ribosomes can dock at the start codon only when the first ribosome has vacated the initiation site. Here we show that loading of the second ribosome on a natural 38-nt-long 5′ untranslated region of lpp mRNA, which codes for the outer membrane lipoprotein from Escherichia coli, takes place before the leading ribosome has moved away from the start codon. The rapid formation of this standby complex depends on the presence of ribosomal proteins S1/S2 in the leading ribosome. The early recruitment of the second ribosome to the standby site before translation by the leading ribosome and the tight coupling between translation elongation by the first ribosome and the accommodation of the second ribosome can contribute to high translational efficiency of the lpp mRNA.
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31
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Ludwig P, Huber M, Lehr M, Wegener M, Zerulla K, Lange C, Soppa J. Non-canonical Escherichia coli transcripts lacking a Shine-Dalgarno motif have very different translational efficiencies and do not form a coherent group. MICROBIOLOGY-SGM 2018; 164:646-658. [PMID: 29469690 DOI: 10.1099/mic.0.000619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Translation initiation in 50-70 % of transcripts in Escherichia coli requires base pairing between the Shine-Dalgarno (SD) motif in the mRNA and the anti-SD motif at the 3' end of the 16S rRNA. However, 30-50 % of E. coli transcripts are non-canonical and are not preceded by an SD motif. The 5' ends of 44 E. coli transcripts were determined, all of which contained a 5'-UTR (no leaderless transcripts), but only a minority contained an SD motif. The 5'-UTR lengths were compared with those listed in RegulonDB and reported in previous publications, and the identities and differences were obtained in all possible combinations. We aimed to quantify the translational efficiencies of non-canonical 5'-UTRs using GusA reporter gene assays and Northern blot analyses. Ten non-canonical 5'-UTRs and two control 5'-UTRs with an SD motif were cloned upstream of the gusA gene. The translational efficiencies were quantified under five different conditions (different growth rates via two different temperatures and two different carbon sources, and heat shock). The translational efficiencies of the non-canonical 5'-UTRs varied widely, from 5 to 384 % of the positive control. In addition, the non-canonical transcripts did not exhibit a common regulatory pattern with changing environmental parameters. No correlation could be observed between the translational efficiencies of the non-canonical 5'-UTRs and their lengths, sequences, GC content, or predicted secondary structures. The introduction of an SD motif enhanced the translational efficiency of a poorly translated non-canonical transcript, while the efficiency of a well-translated non-canonical transcript remained unchanged. Taken together, the mechanisms of translation initiation at non-canonical transcripts in E. coli still need to be elucidated.
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Affiliation(s)
- Petra Ludwig
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Madeleine Huber
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Matthias Lehr
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Marius Wegener
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Karolin Zerulla
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Christian Lange
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
| | - Joerg Soppa
- Goethe University, Institute for Molecular Biosciences, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
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32
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A set of synthetic versatile genetic control elements for the efficient expression of genes in Actinobacteria. Sci Rep 2018; 8:491. [PMID: 29323285 PMCID: PMC5765039 DOI: 10.1038/s41598-017-18846-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022] Open
Abstract
The design and engineering of secondary metabolite gene clusters that are characterized by complicated genetic organization, require the development of collections of well-characterized genetic control elements that can be reused reliably. Although a few intrinsic terminators and RBSs are used routinely, their translation and termination efficiencies have not been systematically studied in Actinobacteria. Here, we analyzed the influence of the regions surrounding RBSs on gene expression in these bacteria. We demonstrated that inappropriate RBSs can reduce the expression efficiency of a gene to zero. We developed a genetic device – an in vivo RBS-selector – that allows selection of an optimal RBS for any gene of interest, enabling rational control of the protein expression level. In addition, a genetic tool that provides the opportunity for measurement of termination efficiency was developed. Using this tool, we found strong terminators that lead to a 17–100-fold reduction in downstream expression and are characterized by sufficient sequence diversity to reduce homologous recombination when used with other elements. For the first time, a C-terminal degradation tag was employed for the control of protein stability in Streptomyces. Finally, we describe a collection of regulatory elements that can be used to control metabolic pathways in Actinobacteria.
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33
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A general mechanism of ribosome dimerization revealed by single-particle cryo-electron microscopy. Nat Commun 2017; 8:722. [PMID: 28959045 PMCID: PMC5620043 DOI: 10.1038/s41467-017-00718-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 07/20/2017] [Indexed: 12/15/2022] Open
Abstract
Bacteria downregulate their ribosomal activity through dimerization of 70S ribosomes, yielding inactive 100S complexes. In Escherichia coli, dimerization is mediated by the hibernation promotion factor (HPF) and ribosome modulation factor. Here we report the cryo-electron microscopy study on 100S ribosomes from Lactococcus lactis and a dimerization mechanism involving a single protein: HPFlong. The N-terminal domain of HPFlong binds at the same site as HPF in Escherichia coli 100S ribosomes. Contrary to ribosome modulation factor, the C-terminal domain of HPFlong binds exactly at the dimer interface. Furthermore, ribosomes from Lactococcus lactis do not undergo conformational changes in the 30S head domains upon binding of HPFlong, and the Shine–Dalgarno sequence and mRNA entrance tunnel remain accessible. Ribosome activity is blocked by HPFlong due to the inhibition of mRNA recognition by the platform binding center. Phylogenetic analysis of HPF proteins suggests that HPFlong-mediated dimerization is a widespread mechanism of ribosome hibernation in bacteria. When bacteria enter the stationary growth phase, protein translation is suppressed via the dimerization of 70S ribosomes into inactive complexes. Here the authors provide a structural basis for how the dual domain hibernation promotion factor promotes ribosome dimerization and hibernation in bacteria.
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34
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Espah Borujeni A, Cetnar D, Farasat I, Smith A, Lundgren N, Salis HM. Precise quantification of translation inhibition by mRNA structures that overlap with the ribosomal footprint in N-terminal coding sequences. Nucleic Acids Res 2017; 45:5437-5448. [PMID: 28158713 PMCID: PMC5435973 DOI: 10.1093/nar/gkx061] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/24/2017] [Indexed: 02/06/2023] Open
Abstract
A mRNA's translation rate is controlled by several sequence determinants, including the presence of RNA structures within the N-terminal regions of its coding sequences. However, the physical rules that govern when such mRNA structures will inhibit translation remain unclear. Here, we introduced systematically designed RNA hairpins into the N-terminal coding region of a reporter protein with steadily increasing distances from the start codon, followed by characterization of their mRNA and expression levels in Escherichia coli. We found that the mRNAs' translation rates were repressed, by up to 530-fold, when mRNA structures overlapped with the ribosome's footprint. In contrast, when the mRNA structure was located outside the ribosome's footprint, translation was repressed by <2-fold. By combining our measurements with biophysical modeling, we determined that the ribosomal footprint extends 13 nucleotides into the N-terminal coding region and, when a mRNA structure overlaps or partially overlaps with the ribosomal footprint, the free energy to unfold only the overlapping structure controlled the extent of translation repression. Overall, our results provide precise quantification of the rules governing translation initiation at N-terminal coding regions, improving the predictive design of post-transcriptional regulatory elements that regulate translation rate.
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Affiliation(s)
- Amin Espah Borujeni
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Daniel Cetnar
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Iman Farasat
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Ashlee Smith
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Natasha Lundgren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Howard M Salis
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.,Department of Biological Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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35
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Klaholz BP. The Ribosome Holds the RNA Polymerase on Track in Bacteria. Trends Biochem Sci 2017; 42:686-689. [PMID: 28801047 DOI: 10.1016/j.tibs.2017.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
Abstract
The central dogma of molecular biology comprises two fundamental mechanistic steps of gene expression (transcription and translation), which, in bacteria, are coupled. A recent study provides structural insights into a supercomplex between the RNA polymerase and the ribosome, thus highlighting the synergy between two key macromolecular machineries in the cell.
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Affiliation(s)
- Bruno P Klaholz
- Centre for Integrative Biology (CBI), Department of Integrated Structural Biology, IGBMC (Institute of Genetics and of Molecular and Cellular Biology), 1 rue Laurent Fries, Illkirch, France; Centre National de la Recherche Scientifique (CNRS) UMR 7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM) U964, Illkirch, France; Université de Strasbourg, Strasbourg, France.
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36
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Vigar JRJ, Wieden HJ. Engineering bacterial translation initiation - Do we have all the tools we need? Biochim Biophys Acta Gen Subj 2017; 1861:3060-3069. [PMID: 28315412 DOI: 10.1016/j.bbagen.2017.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 03/03/2017] [Accepted: 03/10/2017] [Indexed: 01/17/2023]
Abstract
BACKGROUND Reliable tools that allow precise and predictable control over gene expression are critical for the success of nearly all bioengineering applications. Translation initiation is the most regulated phase during protein biosynthesis, and is therefore a promising target for exerting control over gene expression. At the translational level, the copy number of a protein can be fine-tuned by altering the interaction between the translation initiation region of an mRNA and the ribosome. These interactions can be controlled by modulating the mRNA structure using numerous approaches, including small molecule ligands, RNAs, or RNA-binding proteins. A variety of naturally occurring regulatory elements have been repurposed, facilitating advances in synthetic gene regulation strategies. The pursuit of a comprehensive understanding of mechanisms governing translation initiation provides the framework for future engineering efforts. SCOPE OF REVIEW Here we outline state-of-the-art strategies used to predictably control translation initiation in bacteria. We also discuss current limitations in the field and future goals. MAJOR CONCLUSIONS Due to its function as the rate-determining step, initiation is the ideal point to exert effective translation regulation. Several engineering tools are currently available to rationally design the initiation characteristics of synthetic mRNAs. However, improvements are required to increase the predictability, effectiveness, and portability of these tools. GENERAL SIGNIFICANCE Predictable and reliable control over translation initiation will allow greater predictability when designing, constructing, and testing genetic circuits. The ability to build more complex circuits predictably will advance synthetic biology and contribute to our fundamental understanding of the underlying principles of these processes. "This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Justin R J Vigar
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
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37
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Duval M, Marenna A, Chevalier C, Marzi S. Site-Directed Chemical Probing to map transient RNA/protein interactions. Methods 2016; 117:48-58. [PMID: 28027957 DOI: 10.1016/j.ymeth.2016.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/11/2016] [Accepted: 12/21/2016] [Indexed: 12/24/2022] Open
Abstract
RNA-protein interactions are at the bases of many biological processes, forming either tight and stable functional ribonucleoprotein (RNP) complexes (i.e. the ribosome) or transitory ones, such as the complexes involving RNA chaperone proteins. To localize the sites where a protein interacts on an RNA molecule, a common simple and inexpensive biochemical method is the footprinting technique. The protein leaves its footprint on the RNA acting as a shield to protect the regions of interaction from chemical modification or cleavages obtained with chemical or enzymatic nucleases. This method has proven its efficiency to study in vitro the organization of stable RNA-protein complexes. Nevertheless, when the protein binds the RNA very dynamically, with high off-rates, protections are very often difficult to observe. For the analysis of these transient complexes, we describe an alternative strategy adapted from the Site Directed Chemical Probing (SDCP) approach and we compare it with classical footprinting. SDCP relies on the modification of the RNA binding protein to tether an RNA probe (usually Fe-EDTA) to specific protein positions. Local cleavages on the regions of interaction can be used to localize the protein and position its domains on the RNA molecule. This method has been used in the past to monitor stable complexes; we provide here a detailed protocol and a practical example of its application to the study of Escherichia coli RNA chaperone protein S1 and its transitory complexes with mRNAs.
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Affiliation(s)
- Mélodie Duval
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Alessandra Marenna
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Clément Chevalier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Stefano Marzi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France.
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38
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Khusainov I, Vicens Q, Bochler A, Grosse F, Myasnikov A, Ménétret JF, Chicher J, Marzi S, Romby P, Yusupova G, Yusupov M, Hashem Y. Structure of the 70S ribosome from human pathogen Staphylococcus aureus. Nucleic Acids Res 2016; 44:10491-10504. [PMID: 27906650 PMCID: PMC5137454 DOI: 10.1093/nar/gkw933] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/02/2016] [Accepted: 10/06/2016] [Indexed: 01/07/2023] Open
Abstract
Comparative structural studies of ribosomes from various organisms keep offering exciting insights on how species-specific or environment-related structural features of ribosomes may impact translation specificity and its regulation. Although the importance of such features may be less obvious within more closely related organisms, their existence could account for vital yet species-specific mechanisms of translation regulation that would involve stalling, cell survival and antibiotic resistance. Here, we present the first full 70S ribosome structure from Staphylococcus aureus, a Gram-positive pathogenic bacterium, solved by cryo-electron microscopy. Comparative analysis with other known bacterial ribosomes pinpoints several unique features specific to S. aureus around a conserved core, at both the protein and the RNA levels. Our work provides the structural basis for the many studies aiming at understanding translation regulation in S. aureus and for designing drugs against this often multi-resistant pathogen.
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Affiliation(s)
- Iskander Khusainov
- Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, Illkirch 67400, France.,Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russia
| | - Quentin Vicens
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - Anthony Bochler
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - François Grosse
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - Alexander Myasnikov
- Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, Illkirch 67400, France
| | - Jean-François Ménétret
- Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, Illkirch 67400, France
| | - Johana Chicher
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
| | - Gulnara Yusupova
- Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, Illkirch 67400, France
| | - Marat Yusupov
- Département de Biologie et de Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Université de Strasbourg, Illkirch 67400, France
| | - Yaser Hashem
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg 67084, France
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39
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Gao R, Yu K, Nie J, Lian T, Jin J, Liljas A, Su XD. Deep sequencing reveals global patterns of mRNA recruitment during translation initiation. Sci Rep 2016; 6:30170. [PMID: 27460773 PMCID: PMC4962057 DOI: 10.1038/srep30170] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/28/2016] [Indexed: 11/10/2022] Open
Abstract
In this work, we developed a method to systematically study the sequence preference of mRNAs during translation initiation. Traditionally, the dynamic process of translation initiation has been studied at the single molecule level with limited sequencing possibility. Using deep sequencing techniques, we identified the sequence preference at different stages of the initiation complexes. Our results provide a comprehensive and dynamic view of the initiation elements in the translation initiation region (TIR), including the S1 binding sequence, the Shine-Dalgarno (SD)/anti-SD interaction and the second codon, at the equilibrium of different initiation complexes. Moreover, our experiments reveal the conformational changes and regional dynamics throughout the dynamic process of mRNA recruitment.
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Affiliation(s)
- Rong Gao
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Kai Yu
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jukui Nie
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Tengfei Lian
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jianshi Jin
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Anders Liljas
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - Xiao-Dong Su
- Biodynamic Optical Imaging Center (BIOPIC), and State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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40
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The molecular choreography of protein synthesis: translational control, regulation, and pathways. Q Rev Biophys 2016; 49:e11. [PMID: 27658712 DOI: 10.1017/s0033583516000056] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Translation of proteins by the ribosome regulates gene expression, with recent results underscoring the importance of translational control. Misregulation of translation underlies many diseases, including cancer and many genetic diseases. Decades of biochemical and structural studies have delineated many of the mechanistic details in prokaryotic translation, and sketched the outlines of eukaryotic translation. However, translation may not proceed linearly through a single mechanistic pathway, but likely involves multiple pathways and branchpoints. The stochastic nature of biological processes would allow different pathways to occur during translation that are biased by the interaction of the ribosome with other translation factors, with many of the steps kinetically controlled. These multiple pathways and branchpoints are potential regulatory nexus, allowing gene expression to be tuned at the translational level. As research focus shifts toward eukaryotic translation, certain themes will be echoed from studies on prokaryotic translation. This review provides a general overview of the dynamic data related to prokaryotic and eukaryotic translation, in particular recent findings with single-molecule methods, complemented by biochemical, kinetic, and structural findings. We will underscore the importance of viewing the process through the viewpoints of regulation, translational control, and heterogeneous pathways.
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Meyer MM. The role of mRNA structure in bacterial translational regulation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27301829 DOI: 10.1002/wrna.1370] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 01/08/2023]
Abstract
The characteristics of bacterial messenger RNAs (mRNAs) that influence translation efficiency provide many convenient handles for regulation of gene expression, especially when coupled with the processes of transcription termination and mRNA degradation. An mRNA's structure, especially near the site of initiation, has profound consequences for how readily it is translated. This property allows bacterial gene expression to be altered by changes to mRNA structure induced by temperature, or interactions with a wide variety of cellular components including small molecules, other RNAs (such as sRNAs and tRNAs), and RNA-binding proteins. This review discusses the links between mRNA structure and translation efficiency, and how mRNA structure is manipulated by conditions and signals within the cell to regulate gene expression. The range of RNA regulators discussed follows a continuum from very complex tertiary structures such as riboswitch aptamers and ribosomal protein-binding sites to thermosensors and mRNA:sRNA interactions that involve only base-pairing interactions. Furthermore, the high degrees of diversity observed for both mRNA structures and the mechanisms by which inhibition of translation occur have significant consequences for understanding the evolution of bacterial translational regulation. WIREs RNA 2017, 8:e1370. doi: 10.1002/wrna.1370 For further resources related to this article, please visit the WIREs website.
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Rodnina MV. The ribosome in action: Tuning of translational efficiency and protein folding. Protein Sci 2016; 25:1390-406. [PMID: 27198711 DOI: 10.1002/pro.2950] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 12/28/2022]
Abstract
The cellular proteome is shaped by the combined activities of the gene expression and quality control machineries. While transcription plays an undoubtedly important role, in recent years also translation emerged as a key step that defines the composition and quality of the proteome and the functional activity of proteins in the cell. Among the different post-transcriptional control mechanisms, translation initiation and elongation provide multiple checkpoints that can affect translational efficiency. A multitude of specific signals in mRNAs can determine the frequency of translation initiation, choice of the open reading frame, global and local elongation velocities, and the folding of the emerging protein. In addition to specific signatures in the mRNAs, also variations in the global pools of translation components, including ribosomes, tRNAs, mRNAs, and translation factors can alter translational efficiencies. The cellular outcomes of phenomena such as mRNA codon bias are sometimes difficult to understand due to the staggering complexity of covariates that affect codon usage, translation, and protein folding. Here we summarize the experimental evidence on how the ribosome-together with the other components of the translational machinery-can alter translational efficiencies of mRNA at the initiation and elongation stages and how translation velocity affects protein folding. We seek to explain these findings in the context of mechanistic work on the ribosome. The results argue in favour of a new understanding of translation control as a hub that links mRNA homeostasis to production and quality control of proteins in the cell.
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Affiliation(s)
- Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany
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Balbontín R, Villagra N, Pardos de la Gándara M, Mora G, Figueroa-Bossi N, Bossi L. Expression of IroN, the salmochelin siderophore receptor, requires mRNA activation by RyhB small RNA homologues. Mol Microbiol 2016; 100:139-55. [PMID: 26710935 DOI: 10.1111/mmi.13307] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2015] [Indexed: 12/21/2022]
Abstract
The iroN gene of Salmonella enterica and uropathogenic Escherichia coli encodes the outer membrane receptor of Fe(3+) -bound salmochelin, a siderophore tailored to evade capture by the host's immune system. The iroN gene is under negative control of the Fur repressor and transcribed under iron limiting conditions. We show here that transcriptional de-repression is not sufficient to allow iroN expression, as this also requires activation by either of two partially homologous small RNAs (sRNAs), RyhB1 and RyhB2. The two sRNAs target the same sequence segment approximately in the middle of the 94-nucleotide 5' untranslated region (UTR) of iroN mRNA. Several lines of evidence suggest that base pair interaction stimulates iroN mRNA translation. Activation does not result from the disruption of a secondary structure masking the ribosome binding site; rather it involves sequences at the 5' end of iroN 5' UTR. In vitro 'toeprint' assays revealed that this upstream site binds the 30S ribosomal subunit provided that RyhB1 is paired with the mRNA. Altogether, our data suggest that RyhB1, and to lesser extent RyhB2, activate iroN mRNA translation by promoting entry of the ribosome at an upstream 'standby' site. These findings add yet an additional nuance to the polychromatic landscape of sRNA-mediated regulation.
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Affiliation(s)
- Roberto Balbontín
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Nicolás Villagra
- Laboratorio de Patogénesis Molecular y Antimicrobianos, Facultad de Medicina, Universidad Andres Bello, Echaurren 183, Santiago, Chile
| | - Maria Pardos de la Gándara
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Guido Mora
- Laboratorio de Patogénesis Molecular y Antimicrobianos, Facultad de Medicina, Universidad Andres Bello, Echaurren 183, Santiago, Chile
| | - Nara Figueroa-Bossi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Lionello Bossi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France
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44
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Fechter P, Parmentier D, Wu Z, Fuchsbauer O, Romby P, Marzi S. Traditional Chemical Mapping of RNA Structure In Vitro and In Vivo. Methods Mol Biol 2016; 1490:83-103. [PMID: 27665595 DOI: 10.1007/978-1-4939-6433-8_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Chemical probing is often used to gain knowledge on the secondary and tertiary structures of RNA molecules either free or engaged in complexes with ligands. The method monitors the reactivity of each nucleotide towards chemicals of various specificities reflecting the hydrogen bonding environment of each nucleotide within the RNA molecule. In addition, information can be obtained on the binding site of a ligand (noncoding RNAs, protein, metabolites), and on RNA conformational changes that accompanied ligand binding or perturbation of the environmental cues. The detection of the modifications can be obtained either by using end-labeled RNA molecules or by primer extension using reverse transcriptase. The goal of this chapter is to provide the reader with an experimental guide to probe the structure of RNA in vitro and in vivo with the most suitable chemical probes.
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Affiliation(s)
- Pierre Fechter
- Biotechnologie et Signalisation Cellulaire, CNRS-INSERM, ESBS, Université de Strasbourg, 300 boulevard Sebastien Brant, Illkirch, 67412, France
| | - Delphine Parmentier
- Architecture et Réactivité de l'ARN, CNRS, IBMC, Université de Strasbourg, 15 rue René Descartes, 67084, Strasbourg, France
| | - ZongFu Wu
- College of Veterinary Medicine, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Olivier Fuchsbauer
- Architecture et Réactivité de l'ARN, CNRS, IBMC, Université de Strasbourg, 15 rue René Descartes, 67084, Strasbourg, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, CNRS, IBMC, Université de Strasbourg, 15 rue René Descartes, 67084, Strasbourg, France.
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, CNRS, IBMC, Université de Strasbourg, 15 rue René Descartes, 67084, Strasbourg, France
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45
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Quantitative relationship between the mRNA secondary structure of translational initiation region and the expression level of heterologous protein in Escherichia coli. ACTA ACUST UNITED AC 2016; 43:97-102. [DOI: 10.1007/s10295-015-1699-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/30/2015] [Indexed: 12/12/2022]
Abstract
Abstract
Translational efficiency in Escherichia coli is strongly influenced by mRNA secondary structure of translational initiation region (TIR). We have previously reported that the expression of heterologous protein is directly related to the minimal folding free energy (ΔG) of the local secondary structure. However, identifying biologically relevant maximum and minimum levels of expression, or exploring the optimal level between them, is a key to successful optimization of heterologous protein expression. To systematically search a large range of the ΔG of TIR, we now present a quantitative analysis of the relationship between expression level and these ΔGs. The ΔG of TIR in green fluorescent protein is found to be linearly correlated with the fluorescence intensity over a range of tenfold change. The result demonstrates that the increasing ΔG of TIR can enhance the expression level linearly with no threshold or plateau.
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46
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Palmer SR, Burne RA. Post-transcriptional regulation by distal Shine-Dalgarno sequences in the grpE-dnaK intergenic region of Streptococcus mutans. Mol Microbiol 2015; 98:302-17. [PMID: 26172310 DOI: 10.1111/mmi.13122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2015] [Indexed: 12/24/2022]
Abstract
A unique 373 bp region (igr66) between grpE and dnaK of Streptococcus mutans lacks a promoter but is required for optimal production of DnaK. Northern blotting using probes specific to hrcA, igr66 or dnaK revealed multiple transcripts produced from the dnaK operon and 5'-RACE mapped 5' termini of multiple dnaK transcripts within igr66. One product mapped to a predicted 5'-SL (stem-loop) and two others mapped just 5' to Shine-Dalgarno (SD)-like sequences located immediately upstream to dnaK and to a predicted SL 120 bp upstream of the dnaK start codon (3'-SL). A collection of cat reporter-gene strains containing mutant derivatives of igr66 were engineered. Chloramphenicol acetyltransferase (CAT) activity varied greatly between strains, but there were no correlative changes in cat mRNA levels. Interestingly, mutations introduced into the SD-like sequences 5' to the 3'-SL resulted in an 83-98% decrease in CAT activity. Markerless point mutations introduced upstream of dnaK in the SD-like sequences impaired growth at elevated temperatures and resulted in up to a 40% decrease in DnaK protein after heat shock. Collectively, these results indicate processing within igr66 enhances translation in a temperature dependent manner via non-canonical ribosome binding sites positioned >120 bp upstream of dnaK.
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Affiliation(s)
- Sara R Palmer
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
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47
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Gualerzi CO, Pon CL. Initiation of mRNA translation in bacteria: structural and dynamic aspects. Cell Mol Life Sci 2015; 72:4341-67. [PMID: 26259514 PMCID: PMC4611024 DOI: 10.1007/s00018-015-2010-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 01/12/2023]
Abstract
Initiation of mRNA translation is a major checkpoint for regulating level and fidelity of protein synthesis. Being rate limiting in protein synthesis, translation initiation also represents the target of many post-transcriptional mechanisms regulating gene expression. The process begins with the formation of an unstable 30S pre-initiation complex (30S pre-IC) containing initiation factors (IFs) IF1, IF2 and IF3, the translation initiation region of an mRNA and initiator fMet-tRNA whose codon and anticodon pair in the P-site following a first-order rearrangement of the 30S pre-IC produces a locked 30S initiation complex (30SIC); this is docked by the 50S subunit to form a 70S complex that, following several conformational changes, positional readjustments of its ligands and ejection of the IFs, becomes a 70S initiation complex productive in initiation dipeptide formation. The first EF-G-dependent translocation marks the beginning of the elongation phase of translation. Here, we review structural, mechanistic and dynamical aspects of this process.
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MESH Headings
- Bacteria/genetics
- Bacteria/metabolism
- Binding Sites/genetics
- Codon, Initiator/genetics
- Codon, Initiator/metabolism
- Models, Genetic
- Nucleic Acid Conformation
- Peptide Initiation Factors/genetics
- Peptide Initiation Factors/metabolism
- Protein Biosynthesis
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Transfer, Met/chemistry
- RNA, Transfer, Met/genetics
- RNA, Transfer, Met/metabolism
- Ribosomes/metabolism
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Affiliation(s)
| | - Cynthia L Pon
- Laboratory of Genetics, University of Camerino, 62032, Camerino, Italy.
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48
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Beinsteiner B, Michalon J, Klaholz BP. IBiSS, a versatile and interactive tool for integrated sequence and 3D structure analysis of large macromolecular complexes. Bioinformatics 2015; 31:3339-44. [DOI: 10.1093/bioinformatics/btv347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 05/30/2015] [Indexed: 11/13/2022] Open
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49
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Prisic S, Hwang H, Dow A, Barnaby O, Pan TS, Lonzanida JA, Chazin WJ, Steen H, Husson RN. Zinc regulates a switch between primary and alternative S18 ribosomal proteins in Mycobacterium tuberculosis. Mol Microbiol 2015; 97:263-80. [PMID: 25858183 DOI: 10.1111/mmi.13022] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2015] [Indexed: 12/21/2022]
Abstract
The Mycobacterium tuberculosis genome encodes five putative 'alternative' ribosomal proteins whose expression is repressed at high Zn(2+) concentration. Each alternative protein has a primary homologue that is predicted to bind Zn(2+). We hypothesized that zinc triggers a switch between these paired homologous proteins and therefore chose one of these pairs, S18-1/S18-2, to study mechanisms of the predicted competition for their incorporation into ribosomes. Our data show that Zn(2+)-depletion causes accumulation of both S18-2 mRNA and protein. In contrast, S18-1 mRNA levels are unchanged to slightly elevated under Zn(2+)-limited conditions. However, the amount of S18-1 protein is markedly decreased. We further demonstrate that both S18 proteins interact with ribosomal protein S6, a committed step in ribosome biogenesis. Zn(2+) is absolutely required for the S18-1/S6 interaction while it is dispensable for S18-2/S6 dimer formation. These data suggest a model in which S18-1 is the dominant ribosome constituent in high zinc conditions, e.g. inside of phagosomes, but that it can be replaced by S18-2 when zinc is deficient, e.g. in the extracellular milieu. Consequently, Zn(2+)-depletion may serve as a signal for building alternative ribosomes when M. tuberculosis is released from macrophages, to allow survival in the extracellular environment.
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Affiliation(s)
- Sladjana Prisic
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA.,Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | - Hyonson Hwang
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Allexa Dow
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | - Omar Barnaby
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Tenny S Pan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI
| | | | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Hanno Steen
- Department of Pathology, Boston Children's Hospital/Harvard Medical School, Boston, MA
| | - Robert N Husson
- Division of Infectious Diseases, Boston Children's Hospital/Harvard Medical School, Boston, MA
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50
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Majzoub K, Hafirassou ML, Meignin C, Goto A, Marzi S, Fedorova A, Verdier Y, Vinh J, Hoffmann JA, Martin F, Baumert TF, Schuster C, Imler JL. RACK1 controls IRES-mediated translation of viruses. Cell 2015; 159:1086-1095. [PMID: 25416947 DOI: 10.1016/j.cell.2014.10.041] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/16/2014] [Accepted: 10/20/2014] [Indexed: 01/31/2023]
Abstract
Fighting viral infections is hampered by the scarcity of viral targets and their variability, resulting in development of resistance. Viruses depend on cellular molecules-which are attractive alternative targets-for their life cycle, provided that they are dispensable for normal cell functions. Using the model organism Drosophila melanogaster, we identify the ribosomal protein RACK1 as a cellular factor required for infection by internal ribosome entry site (IRES)-containing viruses. We further show that RACK1 is an essential determinant for hepatitis C virus translation and infection, indicating that its function is conserved for distantly related human and fly viruses. Inhibition of RACK1 does not affect Drosophila or human cell viability and proliferation, and RACK1-silenced adult flies are viable, indicating that this protein is not essential for general translation. Our findings demonstrate a specific function for RACK1 in selective mRNA translation and uncover a target for the development of broad antiviral intervention.
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Affiliation(s)
- Karim Majzoub
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Mohamed Lamine Hafirassou
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France
| | - Carine Meignin
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Akira Goto
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Stefano Marzi
- CNRS UPR9002, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Antonina Fedorova
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France
| | | | - Joëlle Vinh
- USR3149, ESPCI ParisTech, 75005 Paris, France
| | - Jules A Hoffmann
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France; Institut d'Etudes Avancées de l'Université de Strasbourg, 67000 Strasbourg, France
| | - Franck Martin
- CNRS UPR9002, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France
| | - Thomas F Baumert
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France; Institut Hospitalo-Universitaire (IHU), Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, 67000 Strasbourg, France
| | - Catherine Schuster
- Université de Strasbourg, 67000 Strasbourg, France; Inserm UMR1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France.
| | - Jean-Luc Imler
- CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, 67000 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France.
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