1
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Li Y, Zhang L, Wang L, Li J, Zhao Y, Liu F, Wang Q. Structure and function of type IV IRES in picornaviruses: a systematic review. Front Microbiol 2024; 15:1415698. [PMID: 38855772 PMCID: PMC11157119 DOI: 10.3389/fmicb.2024.1415698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 05/13/2024] [Indexed: 06/11/2024] Open
Abstract
The Picornaviridae is a family of icosahedral viruses with single-stranded, highly diverse positive-sense RNA genomes. Virions consist of a capsid, without envelope, surrounding a core of RNA genome. A typical genome of picornavirus harbors a well-conserved and highly structured RNA element known as the internal ribosome entry site (IRES), functionally essential for viral replication and protein translation. Based on differences in their structures and mechanisms of action, picornaviral IRESs have been categorized into five types: type I, II, III, IV, and V. Compared with the type IV IRES, the others not only are structurally complicated, but also involve multiple initiation factors for triggering protein translation. The type IV IRES, often referred to as hepatitis C virus (HCV)-like IRES due to its structural resemblance to the HCV IRES, exhibits a simpler and more compact structure than those of the other four. The increasing identification of picornaviruses with the type IV IRES suggests that this IRES type seems to reveal strong retention and adaptation in terms of viral evolution. Here, we systematically reviewed structural features and biological functions of the type IV IRES in picornaviruses. A comprehensive understanding of the roles of type IV IRESs will contribute to elucidating the replication mechanism and pathogenesis of picornaviruses.
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Affiliation(s)
- Yan Li
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
- Qingdao Center for Animal Disease Control and Prevention, Qingdao, China
| | - Lei Zhang
- Shandong New Hope Liuhe Group Co., Ltd., Qingdao, China
| | - Ling Wang
- University Hospital, Qingdao Agricultural University, Qingdao, China
| | - Jing Li
- Market Supervision Administration of Huangdao District, Qingdao, China
| | - Yanwei Zhao
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Fuxiao Liu
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Qianqian Wang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
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2
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Tants JN, Schlundt A. Advances, Applications, and Perspectives in Small-Angle X-ray Scattering of RNA. Chembiochem 2023; 24:e202300110. [PMID: 37466350 DOI: 10.1002/cbic.202300110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/22/2023] [Indexed: 07/20/2023]
Abstract
RNAs exhibit a plethora of functions far beyond transmitting genetic information. Often, RNA functions are entailed in their structure, be it as a regulatory switch, protein binding site, or providing catalytic activity. Structural information is a prerequisite for a full understanding of RNA-regulatory mechanisms. Owing to the inherent dynamics, size, and instability of RNA, its structure determination remains challenging. Methods such as NMR spectroscopy, X-ray crystallography, and cryo-electron microscopy can provide high-resolution structures; however, their limitations make structure determination, even for small RNAs, cumbersome, if at all possible. Although at a low resolution, small-angle X-ray scattering (SAXS) has proven valuable in advancing structure determination of RNAs as a complementary method, which is also applicable to large-sized RNAs. Here, we review the technological and methodological advancements of RNA SAXS. We provide examples of the powerful inclusion of SAXS in structural biology and discuss possible future applications to large RNAs.
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Affiliation(s)
- Jan-Niklas Tants
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Andreas Schlundt
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438, Frankfurt, Germany
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3
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Deng J, Fang X, Huang L, Li S, Xu L, Ye K, Zhang J, Zhang K, Zhang QC. RNA structure determination: From 2D to 3D. FUNDAMENTAL RESEARCH 2023; 3:727-737. [PMID: 38933295 PMCID: PMC11197651 DOI: 10.1016/j.fmre.2023.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/28/2024] Open
Abstract
RNA molecules serve a wide range of functions that are closely linked to their structures. The basic structural units of RNA consist of single- and double-stranded regions. In order to carry out advanced functions such as catalysis and ligand binding, certain types of RNAs can adopt higher-order structures. The analysis of RNA structures has progressed alongside advancements in structural biology techniques, but it comes with its own set of challenges and corresponding solutions. In this review, we will discuss recent advances in RNA structure analysis techniques, including structural probing methods, X-ray crystallography, nuclear magnetic resonance, cryo-electron microscopy, and small-angle X-ray scattering. Often, a combination of multiple techniques is employed for the integrated analysis of RNA structures. We also survey important RNA structures that have been recently determined using various techniques.
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Affiliation(s)
- Jie Deng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - Xianyang Fang
- Beijing Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - Shanshan Li
- MOE Key Laboratory for Cellular Dynamics and Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Lilei Xu
- Beijing Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Keqiong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinsong Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Kaiming Zhang
- MOE Key Laboratory for Cellular Dynamics and Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Qiangfeng Cliff Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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4
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Mathez G, Cagno V. Small Molecules Targeting Viral RNA. Int J Mol Sci 2023; 24:13500. [PMID: 37686306 PMCID: PMC10487773 DOI: 10.3390/ijms241713500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
The majority of antivirals available target viral proteins; however, RNA is emerging as a new and promising antiviral target due to the presence of highly structured RNA in viral genomes fundamental for their replication cycle. Here, we discuss methods for the identification of RNA-targeting compounds, starting from the determination of RNA structures either from purified RNA or in living cells, followed by in silico screening on RNA and phenotypic assays to evaluate viral inhibition. Moreover, we review the small molecules known to target the programmed ribosomal frameshifting element of SARS-CoV-2, the internal ribosomal entry site of different viruses, and RNA elements of HIV.
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Affiliation(s)
| | - Valeria Cagno
- Institute of Microbiology, University Hospital of Lausanne, University of Lausanne, 1011 Lausanne, Switzerland
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5
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Sabei A, Caldas Baia TG, Saffar R, Martin J, Frezza E. Internal Normal Mode Analysis Applied to RNA Flexibility and Conformational Changes. J Chem Inf Model 2023; 63:2554-2572. [PMID: 36972178 DOI: 10.1021/acs.jcim.2c01509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
We investigated the capability of internal normal modes to reproduce RNA flexibility and predict observed RNA conformational changes and, notably, those induced by the formation of RNA-protein and RNA-ligand complexes. Here, we extended our iNMA approach developed for proteins to study RNA molecules using a simplified representation of the RNA structure and its potential energy. Three data sets were also created to investigate different aspects. Despite all the approximations, our study shows that iNMA is a suitable method to take into account RNA flexibility and describe its conformational changes opening the route to its applicability in any integrative approach where these properties are crucial.
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6
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Zerfu B, Kassa T, Legesse M. Epidemiology, biology, pathogenesis, clinical manifestations, and diagnosis of dengue virus infection, and its trend in Ethiopia: a comprehensive literature review. Trop Med Health 2023; 51:11. [PMID: 36829222 PMCID: PMC9950709 DOI: 10.1186/s41182-023-00504-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/15/2023] [Indexed: 02/26/2023] Open
Abstract
Dengue fever is a dengue virus infection, emerging rapidly and posing public health threat worldwide, primarily in tropical and subtropical countries. Nearly half of the world's population is now at risk of contracting the dengue virus, including new countries with no previous history-like Ethiopia. However, little is known about the epidemiology and impact of the disease in different countries. This is especially true in countries, where cases have recently begun to be reported. This review aims to summarize epidemiology, biology, pathogenesis, clinical manifestations, and diagnosis of dengue virus infection and its trend in Ethiopia. It may help countries, where dengue fever is not yet on the public health list-like Ethiopia to alert healthcare workers to consider the disease for diagnosis and treatment. The review retrieved and incorporated 139 published and organizational reports showing approximately 390 million new infections. About 100 million of these infections develop the clinical features of dengue, and thousands of people die annually from severe dengue fever in 129 countries. It is caused by being bitten by a dengue virus-infected female mosquito, primarily Aedes aegypti and, lesser, Ae. albopictus. Dengue virus is a member of the Flavivirus genus of the Flaviviridae family and has four independent but antigen-related single-stranded positive-sense RNA virus serotypes. The infection is usually asymptomatic but causes illnesses ranging from mild febrile illness to fatal dengue hemorrhagic fever or shock syndrome. Diagnosis can be by detecting the virus genome using nucleic acids amplification tests or testing NS1 antigen and/or anti-dengue antibodies from serum, plasma, circulating blood cells, or other tissues. Dengue cases and outbreaks have increased in recent decades, with a significant public health impact. Ethiopia has had nearly annual outbreaks since 2013, devastating an already fragmented health system and economy. Standardization of medication, population-level screening for early diagnosis and prompt treatment, and minimization of mosquito bites reduce overall infection and mortality rates.
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Affiliation(s)
- Biruk Zerfu
- Department of Medical Laboratory Science, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia. .,Aklilu Lema Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Tesfu Kassa
- grid.7123.70000 0001 1250 5688Aklilu Lema Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Mengistu Legesse
- grid.7123.70000 0001 1250 5688Aklilu Lema Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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7
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Matarrese MAG, Loppini A, Nicoletti M, Filippi S, Chiodo L. Assessment of tools for RNA secondary structure prediction and extraction: a final-user perspective. J Biomol Struct Dyn 2022:1-20. [DOI: 10.1080/07391102.2022.2116110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Margherita A. G. Matarrese
- Engineering Department, Campus Bio-Medico University of Rome, Rome, Italy
- Jane and John Justin Neurosciences Center, Cook Children’s Health Care System, TX, USA
- Department of Bioengineering, The University of Texas at Arlington, Arlington, TX, USA
| | - Alessandro Loppini
- Engineering Department, Campus Bio-Medico University of Rome, Rome, Italy
- Center for Life Nano & Neuroscience, Italian Institute of Technology, Rome, Italy
| | - Martina Nicoletti
- Engineering Department, Campus Bio-Medico University of Rome, Rome, Italy
- Center for Life Nano & Neuroscience, Italian Institute of Technology, Rome, Italy
| | - Simonetta Filippi
- Engineering Department, Campus Bio-Medico University of Rome, Rome, Italy
| | - Letizia Chiodo
- Engineering Department, Campus Bio-Medico University of Rome, Rome, Italy
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8
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Manigrasso J, Marcia M, De Vivo M. Computer-aided design of RNA-targeted small molecules: A growing need in drug discovery. Chem 2021. [DOI: 10.1016/j.chempr.2021.05.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Winkler C, King M, Berthe J, Ferraioli D, Garuti A, Grillo F, Rodriguez-Canales J, Ferrando L, Chopin N, Ray-Coquard I, Delpuech O, Rinchai D, Bedognetti D, Ballestrero A, Leo E, Zoppoli G. SLFN11 captures cancer-immunity interactions associated with platinum sensitivity in high-grade serous ovarian cancer. JCI Insight 2021; 6:146098. [PMID: 34549724 PMCID: PMC8492341 DOI: 10.1172/jci.insight.146098] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/28/2021] [Indexed: 01/30/2023] Open
Abstract
Large independent analyses on cancer cell lines followed by functional studies have identified Schlafen 11 (SLFN11), a putative helicase, as the strongest predictor of sensitivity to DNA-damaging agents (DDAs), including platinum. However, its role as a prognostic biomarker is undefined, partially due to the lack of validated methods to score SLFN11 in human tissues. Here, we implemented a pipeline to quantify SLFN11 in human cancer samples. By analyzing a cohort of high-grade serous ovarian carcinoma (HGSOC) specimens before platinum-based chemotherapy treatment, we show, for the first time to our knowledge, that SLFN11 density in both the neoplastic and microenvironmental components was independently associated with favorable outcome. We observed SLFN11 expression in both infiltrating innate and adaptive immune cells, and analyses in a second, independent, cohort revealed that SLFN11 was associated with immune activation in HGSOC. We found that platinum treatments activated immune-related pathways in ovarian cancer cells in an SLFN11-dependent manner, representative of tumor-immune transactivation. Moreover, SLFN11 expression was induced in activated, isolated immune cell subpopulations, hinting that SLFN11 in the immune compartment may be an indicator of immune transactivation. In summary, we propose SLFN11 is a dual biomarker capturing simultaneously interconnected immunological and cancer cell–intrinsic functional dispositions associated with sensitivity to DDA treatment.
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Affiliation(s)
| | | | - Julie Berthe
- Translational Medicine, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
| | | | - Anna Garuti
- Department of Internal Medicine and Medical Specialties and
| | - Federica Grillo
- Department of Integrated Surgical and Diagnostic Sciences, University of Genova, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | | | | | | | | | | | | | - Davide Bedognetti
- Department of Internal Medicine and Medical Specialties and.,Cancer Research Department, Sidra Medicine, Doha, Qatar.,Hamad Bin Khalifa University, Doha, Qatar
| | - Alberto Ballestrero
- Department of Internal Medicine and Medical Specialties and.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | | | - Gabriele Zoppoli
- Department of Internal Medicine and Medical Specialties and.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
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10
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Embarc-Buh A, Francisco-Velilla R, Martinez-Salas E. RNA-Binding Proteins at the Host-Pathogen Interface Targeting Viral Regulatory Elements. Viruses 2021; 13:952. [PMID: 34064059 PMCID: PMC8224014 DOI: 10.3390/v13060952] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022] Open
Abstract
Viral RNAs contain the information needed to synthesize their own proteins, to replicate, and to spread to susceptible cells. However, due to their reduced coding capacity RNA viruses rely on host cells to complete their multiplication cycle. This is largely achieved by the concerted action of regulatory structural elements on viral RNAs and a subset of host proteins, whose dedicated function across all stages of the infection steps is critical to complete the viral cycle. Importantly, not only the RNA sequence but also the RNA architecture imposed by the presence of specific structural domains mediates the interaction with host RNA-binding proteins (RBPs), ultimately affecting virus multiplication and spreading. In marked difference with other biological systems, the genome of positive strand RNA viruses is also the mRNA. Here we focus on distinct types of positive strand RNA viruses that differ in the regulatory elements used to promote translation of the viral RNA, as well as in the mechanisms used to evade the series of events connected to antiviral response, including translation shutoff induced in infected cells, assembly of stress granules, and trafficking stress.
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Affiliation(s)
| | | | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049 Madrid, Spain; (A.E.-B.); (R.F.-V.)
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11
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Tavares RDCA, Mahadeshwar G, Wan H, Huston NC, Pyle AM. The global and local distribution of RNA structure throughout the SARS-CoV-2 genome. J Virol 2021; 95:JVI.02190-20. [PMID: 33268519 PMCID: PMC8092842 DOI: 10.1128/jvi.02190-20] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 11/30/2020] [Indexed: 02/08/2023] Open
Abstract
SARS-CoV-2 is the causative viral agent of COVID-19, the disease at the center of the current global pandemic. While knowledge of highly structured regions is integral for mechanistic insights into the viral infection cycle, very little is known about the location and folding stability of functional elements within the massive, ∼30kb SARS-CoV-2 RNA genome. In this study, we analyze the folding stability of this RNA genome relative to the structural landscape of other well-known viral RNAs. We present an in-silico pipeline to predict regions of high base pair content across long genomes and to pinpoint hotspots of well-defined RNA structures, a method that allows for direct comparisons of RNA structural complexity within the several domains in SARS-CoV-2 genome. We report that the SARS-CoV-2 genomic propensity for stable RNA folding is exceptional among RNA viruses, superseding even that of HCV, one of the most structured viral RNAs in nature. Furthermore, our analysis suggests varying levels of RNA structure across genomic functional regions, with accessory and structural ORFs containing the highest structural density in the viral genome. Finally, we take a step further to examine how individual RNA structures formed by these ORFs are affected by the differences in genomic and subgenomic contexts, which given the technical difficulty of experimentally separating cellular mixtures of sgRNA from gRNA, is a unique advantage of our in-silico pipeline. The resulting findings provide a useful roadmap for planning focused empirical studies of SARS-CoV-2 RNA biology, and a preliminary guide for exploring potential SARS-CoV-2 RNA drug targets.Importance The RNA genome of SARS-CoV-2 is among the largest and most complex viral genomes, and yet its RNA structural features remain relatively unexplored. Since RNA elements guide function in most RNA viruses, and they represent potential drug targets, it is essential to chart the architectural features of SARS-CoV-2 and pinpoint regions that merit focused study. Here we show that RNA folding stability of SARS-CoV-2 genome is exceptional among viral genomes and we develop a method to directly compare levels of predicted secondary structure across SARS-CoV-2 domains. Remarkably, we find that coding regions display the highest structural propensity in the genome, forming motifs that differ between the genomic and subgenomic contexts. Our approach provides an attractive strategy to rapidly screen for candidate structured regions based on base pairing potential and provides a readily interpretable roadmap to guide functional studies of RNA viruses and other pharmacologically relevant RNA transcripts.
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Affiliation(s)
| | - Gandhar Mahadeshwar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Han Wan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Nicholas C Huston
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Anna Marie Pyle
- Department of Chemistry, Yale University, New Haven, CT 06511, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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12
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Ashraf MU, Salman HM, Khalid MF, Khan MHF, Anwar S, Afzal S, Idrees M, Chaudhary SU. CRISPR-Cas13a mediated targeting of hepatitis C virus internal-ribosomal entry site (IRES) as an effective antiviral strategy. Biomed Pharmacother 2021; 136:111239. [PMID: 33454599 DOI: 10.1016/j.biopha.2021.111239] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/28/2020] [Accepted: 12/31/2020] [Indexed: 12/13/2022] Open
Abstract
Hepatitis C is an inflammatory liver disease caused by the single-stranded RNA (ssRNA) hepatitis C virus (HCV). The genetic diversity of the virus and quasispecies produced during replication have resulted in viral resistance to direct-acting antivirals (DAAs) as well as impediments in vaccine development. The recent adaptation of CRISPR-Cas as an alternative antiviral approach has demonstrated degradation of viral nucleic acids in eukaryotes. In particular, the CRISPR-effector Cas13 enzyme has been shown to target ssRNA viruses effectively. In this work, we have employed Cas13a to knockdown HCV in mammalian cells. Using a computational screen, we identified several potential Cas13a target sites within highly conserved regions of the HCV internal ribosomal entry site (IRES). Our results demonstrate significant inhibition of HCV replication as well as translation in huh-7.5 cells with minimal effects on cell viability. These findings were validated using a multi-modality approach involving qRT-PCR, luciferase assay, and MTT cell viability assay. In conclusion, the CRISPR-Cas13a system efficiently targets HCV in vitro, suggesting its potential as a programmable therapeutic antiviral strategy.
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Affiliation(s)
- Muhammad Usman Ashraf
- Biomedical Informatics Research Laboratory, Department of Biology, Lahore University of Management Sciences, Lahore, Pakistan; Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Hafiz Muhammad Salman
- Biomedical Informatics Research Laboratory, Department of Biology, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Farhan Khalid
- Biomedical Informatics Research Laboratory, Department of Biology, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Haider Farooq Khan
- Biomedical Informatics Research Laboratory, Department of Biology, Lahore University of Management Sciences, Lahore, Pakistan
| | - Saima Anwar
- Department of Biomedical Engineering, University of Engineering and Technology, Lahore, Pakistan
| | - Samia Afzal
- Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Idrees
- Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Safee Ullah Chaudhary
- Biomedical Informatics Research Laboratory, Department of Biology, Lahore University of Management Sciences, Lahore, Pakistan.
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13
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AlMalki WH, Shahid I, Abdalla AN, Johargy AK, Ahmed M, Hassan S. Consensus small interfering RNA targeted to stem-loops II and III of IRES structure of 5' UTR effectively inhibits virus replication and translation of HCV sub-genotype 4a isolates from Saudi Arabia. Saudi J Biol Sci 2021; 28:1109-1122. [PMID: 33424405 PMCID: PMC7785429 DOI: 10.1016/j.sjbs.2020.11.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 12/12/2022] Open
Abstract
Being the most conserved region of all hepatitis C virus (HCV) genotypes and sub-genotypes, the 5′ untranslated region (5′ UTR) of HCV genome signifies it’s importance as a potential target for anti-mRNA based treatment strategies like RNA interference. The advent and approval of first small interference RNA (siRNA) -based treatment of hereditary transthyretin-mediated amyloidosis for clinical use has raised the hopes to test this approach against highly susceptible viruses like HCV. We investigated the antiviral potential of consensus siRNAs targeted to stem-loops (SLs) II and III nucleotide motifs of internal ribosome entry site (IRES) structure within 5′ UTR of HCV sub-genotype 4a isolates from the Saudi population. siRNA inhibitory effects on viral replication and translation of full-length HCV genome were determined in a competent, persistent, and reproducible Huh-7 cell culture system maintained for one month. Maximal inhibition of RNA transcript levels of HCV-IRES clones and silencing of viral replication and translation of full-length virus genome was demonstrated by siRNAs targeted to SL-III nucleotide motifs of IRES in Huh-7 cells. siRNA Usi-169 decreased 5′ UTR RNA transcript levels of HCV-IRES clones up to 75% (P < 0.001) at 24 h post-transfection and 80% (P < 0.001) at 48 h treatment in Huh-7 cells. 5′ UTR-tagged GFP protein expression was significantly decreased from 70 to 80% in Huh-7 cells co-transfected with constructed vectors (i.e. pCR3.1/GFP/5′ UTR) and siRNA Usi-169 at 24 h and 48 h time-span. Viral replication was inhibited by more than 90% (P < 0.001) and HCV core (C) and hypervariable envelope glycoproteins (E1 and E2) expression was also significantly degraded by intracytoplasmic siRNA Usi-169 activity in persistent Huh-7 cell culture system. The findings unveil that siRNAs targeted to 5′ UTR-IRES of HCV sub-genotype 4a Saudi isolates show potent silencing of HCV replication and blocking of viral translation in a persistent in-vitro Huh-7 tissue culture system. Furthermore, we also elucidated that siRNA silencing of viral mRNA not only inhibits viral replication but also blocks viral translation. The results suggest that siRNA potent antiviral activity should be considered as an effective anti-mRNA based treatment strategies for further in-vivo investigations against less studied and harder-to-treat HCV sub-genotype 4a isolates in Saudi Arabia.
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Affiliation(s)
- Waleed H AlMalki
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Al-Abidiyah, P.O. Box 13578, Postal Code 21955, Saudi Arabia
| | - Imran Shahid
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Al-Abidiyah, P.O. Box 13578, Postal Code 21955, Saudi Arabia.,Department of Pharmacology and Toxicology, Faculty of Medicine, Umm Al-Qura University, Al-abidiyah, P.O. Box 13578, Makkah Postal Code 21955, Saudi Arabia
| | - Ashraf N Abdalla
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Al-Abidiyah, P.O. Box 13578, Postal Code 21955, Saudi Arabia
| | - Ayman K Johargy
- Medical Microbiology Department, Faculty of Medicine, Umm Al-Qura University, Al-abidiyah, P.O. Box 13578, Makkah Postal Code 21955, Saudi Arabia
| | - Muhammad Ahmed
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Al-Abidiyah, P.O. Box 13578, Postal Code 21955, Saudi Arabia
| | - Sajida Hassan
- Viral Hepatitis Program, Laboratory of Medicine, University of Washington, Seattle, WA, USA
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14
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Cirauqui Diaz N, Frezza E, Martin J. Using normal mode analysis on protein structural models. How far can we go on our predictions? Proteins 2020; 89:531-543. [PMID: 33349977 DOI: 10.1002/prot.26037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/12/2020] [Indexed: 01/01/2023]
Abstract
Normal mode analysis (NMA) is a fast and inexpensive approach that is largely used to gain insight into functional protein motions, and more recently to create conformations for further computational studies. However, when the protein structure is unknown, the use of computational models is necessary. Here, we analyze the capacity of NMA in internal coordinate space to predict protein motion, its intrinsic flexibility, and atomic displacements, using protein models instead of native structures, and the possibility to use it for model refinement. Our results show that NMA is quite insensitive to modeling errors, but that calculations are strictly reliable only for very accurate models. Our study also suggests that internal NMA is a more suitable tool for the improvement of structural models, and for integrating them with experimental data or in other computational techniques, such as protein docking or more refined molecular dynamics simulations.
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Affiliation(s)
- Nuria Cirauqui Diaz
- CNRS, UMR 5086 Molecular Microbiology and Structural Biochemistry, Université de Lyon, Lyon, France
| | - Elisa Frezza
- CiTCoM, CNRS, Université de Paris, Paris, France
| | - Juliette Martin
- CNRS, UMR 5086 Molecular Microbiology and Structural Biochemistry, Université de Lyon, Lyon, France
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15
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Analytical ultracentrifuge: an ideal tool for characterization of non-coding RNAs. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2020; 49:809-818. [PMID: 33067686 DOI: 10.1007/s00249-020-01470-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/26/2020] [Accepted: 10/05/2020] [Indexed: 12/25/2022]
Abstract
Analytical ultracentrifugation (AUC) has emerged as a robust and reliable technique for biomolecular characterization with extraordinary sensitivity. AUC is widely used to study purity, conformational changes, biomolecular interactions, and stoichiometry. Furthermore, AUC is used to determine the molecular weight of biomolecules such as proteins, carbohydrates, and DNA and RNA. Due to the multifaceted role(s) of non-coding RNAs from viruses, prokaryotes, and eukaryotes, research aimed at understanding the structure-function relationships of non-coding RNAs is rapidly increasing. However, due to their large size, flexibility, complicated secondary structures, and conformations, structural studies of non-coding RNAs are challenging. In this review, we are summarizing the application of AUC to evaluate the homogeneity, interactions, and conformational changes of non-coding RNAs from adenovirus as well as from Murray Valley, Powassan, and West Nile viruses. We also discuss the application of AUC to characterize eukaryotic long non-coding RNAs, Xist, and HOTAIR. These examples highlight the significant role AUC can play in facilitating the structural determination of non-coding RNAs and their complexes.
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16
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Chillón I, Marcia M. The molecular structure of long non-coding RNAs: emerging patterns and functional implications. Crit Rev Biochem Mol Biol 2020; 55:662-690. [PMID: 33043695 DOI: 10.1080/10409238.2020.1828259] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Long non-coding RNAs (lncRNAs) are recently-discovered transcripts that regulate vital cellular processes and are crucially connected to diseases. Despite their unprecedented molecular complexity, it is emerging that lncRNAs possess distinct structural motifs. Remarkably, the 3D shape and topology of full-length, native lncRNAs have been visualized for the first time in the last year. These studies reveal that lncRNA structures dictate lncRNA functions. Here, we review experimentally determined lncRNA structures and emphasize that lncRNA structural characterization requires synergistic integration of computational, biochemical and biophysical approaches. Based on these emerging paradigms, we discuss how to overcome the challenges posed by the complex molecular architecture of lncRNAs, with the goal of obtaining a detailed understanding of lncRNA functions and molecular mechanisms in the future.
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Affiliation(s)
- Isabel Chillón
- European Molecular Biology Laboratory (EMBL) Grenoble, Grenoble, France
| | - Marco Marcia
- European Molecular Biology Laboratory (EMBL) Grenoble, Grenoble, France
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17
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Gupta A, Bansal M. RNA-mediated translation regulation in viral genomes: computational advances in the recognition of sequences and structures. Brief Bioinform 2020; 21:1151-1163. [PMID: 31204430 PMCID: PMC7109810 DOI: 10.1093/bib/bbz054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/24/2019] [Accepted: 04/15/2019] [Indexed: 12/30/2022] Open
Abstract
RNA structures are widely distributed across all life forms. The global conformation of these structures is defined by a variety of constituent structural units such as helices, hairpin loops, kissing-loop motifs and pseudoknots, which often behave in a modular way. Their ubiquitous distribution is associated with a variety of functions in biological processes. The location of these structures in the genomes of RNA viruses is often coordinated with specific processes in the viral life cycle, where the presence of the structure acts as a checkpoint for deciding the eventual fate of the process. These structures have been found to adopt complex conformations and exert their effects by interacting with ribosomes, multiple host translation factors and small RNA molecules like miRNA. A number of such RNA structures have also been shown to regulate translation in viruses at the level of initiation, elongation or termination. The role of various computational studies in the preliminary identification of such sequences and/or structures and subsequent functional analysis has not been fully appreciated. This review aims to summarize the processes in which viral RNA structures have been found to play an active role in translational regulation, their global conformational features and the bioinformatics/computational tools available for the identification and prediction of these structures.
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Affiliation(s)
- Asmita Gupta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Manju Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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18
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Hepatitis C Virus Translation Regulation. Int J Mol Sci 2020; 21:ijms21072328. [PMID: 32230899 PMCID: PMC7178104 DOI: 10.3390/ijms21072328] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/18/2020] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
Translation of the hepatitis C virus (HCV) RNA genome is regulated by the internal ribosome entry site (IRES), located in the 5’-untranslated region (5′UTR) and part of the core protein coding sequence, and by the 3′UTR. The 5′UTR has some highly conserved structural regions, while others can assume different conformations. The IRES can bind to the ribosomal 40S subunit with high affinity without any other factors. Nevertheless, IRES activity is modulated by additional cis sequences in the viral genome, including the 3′UTR and the cis-acting replication element (CRE). Canonical translation initiation factors (eIFs) are involved in HCV translation initiation, including eIF3, eIF2, eIF1A, eIF5, and eIF5B. Alternatively, under stress conditions and limited eIF2-Met-tRNAiMet availability, alternative initiation factors such as eIF2D, eIF2A, and eIF5B can substitute for eIF2 to allow HCV translation even when cellular mRNA translation is downregulated. In addition, several IRES trans-acting factors (ITAFs) modulate IRES activity by building large networks of RNA-protein and protein–protein interactions, also connecting 5′- and 3′-ends of the viral RNA. Moreover, some ITAFs can act as RNA chaperones that help to position the viral AUG start codon in the ribosomal 40S subunit entry channel. Finally, the liver-specific microRNA-122 (miR-122) stimulates HCV IRES-dependent translation, most likely by stabilizing a certain structure of the IRES that is required for initiation.
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19
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Walker MJ, Shortridge MD, Albin DD, Cominsky LY, Varani G. Structure of the RNA Specialized Translation Initiation Element that Recruits eIF3 to the 5'-UTR of c-Jun. J Mol Biol 2020; 432:1841-1855. [PMID: 31953146 PMCID: PMC7225069 DOI: 10.1016/j.jmb.2020.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/10/2019] [Accepted: 01/02/2020] [Indexed: 02/05/2023]
Abstract
Specialized translation initiation is a novel form of regulation of protein synthesis, whereby RNA structures within the 5'-UTR regulate translation rates of specific mRNAs. Similar to internal ribosome entry sites (IRESs), specialized translation initiation requires the recruitment of eukaryotic initiation factor 3 (eIF3), but also requires cap recognition by eIF3d, a new 5'-m7GTP recognizing protein. How these RNA structures mediate eIF3 recruitment to affect translation of specific mRNAs remains unclear. Here, we report the nuclear magnetic resonance (NMR) structure of a stem-loop within the c-JUN 5' UTR recognized by eIF3 and essential for specialized translation initiation of this well-known oncogene. The structure exhibits similarity to eIF3 recognizing motifs found in hepatitis C virus (HCV)-like IRESs, suggesting mechanistic similarities. This work establishes the RNA structural features involved in c-JUN specialized translation initiation and provides a basis to search for small molecule inhibitors of aberrant expression of the proto-oncogenic c-JUN.
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Affiliation(s)
- Matthew J Walker
- Department of Chemistry, University of Washington, Seattle, WA, USA 98195
| | | | - Dreycey D Albin
- Department of Chemistry, University of Washington, Seattle, WA, USA 98195
| | - Lauren Y Cominsky
- Department of Chemistry, University of Washington, Seattle, WA, USA 98195
| | - Gabriele Varani
- Department of Chemistry, University of Washington, Seattle, WA, USA 98195.
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20
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Tabata K, Neufeldt CJ, Bartenschlager R. Hepatitis C Virus Replication. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a037093. [PMID: 31570388 DOI: 10.1101/cshperspect.a037093] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Replication and amplification of the viral genome is a key process for all viruses. For hepatitis C virus (HCV), a positive-strand RNA virus, amplification of the viral genome requires the synthesis of a negative-sense RNA template, which is in turn used for the production of new genomic RNA. This process is governed by numerous proteins, both host and viral, as well as distinct lipids and specific RNA elements within the positive- and negative-strand RNAs. Moreover, this process requires specific changes to host cell ultrastructure to create microenvironments conducive to viral replication. This review will focus on describing the processes and factors involved in facilitating or regulating HCV genome replication.
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Affiliation(s)
- Keisuke Tabata
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany
| | - Christopher J Neufeldt
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, 69120 Heidelberg, Germany.,Division of Virus-Associated Carcinogenesis, German Cancer Research Center, 69120 Heidelberg, Germany.,German Center for Infection Research, Heidelberg Partner Site, 69120 Heidelberg, Germany
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21
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Romero-López C, Berzal-Herranz A. The Role of the RNA-RNA Interactome in the Hepatitis C Virus Life Cycle. Int J Mol Sci 2020; 21:ijms21041479. [PMID: 32098260 PMCID: PMC7073135 DOI: 10.3390/ijms21041479] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 02/05/2023] Open
Abstract
RNA virus genomes are multifunctional entities endowed with conserved structural elements that control translation, replication and encapsidation, among other processes. The preservation of these structural RNA elements constraints the genomic sequence variability. The hepatitis C virus (HCV) genome is a positive, single-stranded RNA molecule with numerous conserved structural elements that manage different steps during the infection cycle. Their function is ensured by the association of protein factors, but also by the establishment of complex, active, long-range RNA-RNA interaction networks-the so-called HCV RNA interactome. This review describes the RNA genome functions mediated via RNA-RNA contacts, and revisits some canonical ideas regarding the role of functional high-order structures during the HCV infective cycle. By outlining the roles of long-range RNA-RNA interactions from translation to virion budding, and the functional domains involved, this work provides an overview of the HCV genome as a dynamic device that manages the course of viral infection.
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22
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Production and Application of Multicistronic Constructs for Various Human Disease Therapies. Pharmaceutics 2019; 11:pharmaceutics11110580. [PMID: 31698727 PMCID: PMC6920891 DOI: 10.3390/pharmaceutics11110580] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/30/2019] [Accepted: 11/03/2019] [Indexed: 01/09/2023] Open
Abstract
The development of multicistronic vectors has opened up new opportunities to address the fundamental issues of molecular and cellular biology related to the need for the simultaneous delivery and joint expression of several genes. To date, the examples of the successful use of multicistronic vectors have been described for the development of new methods of treatment of various human diseases, including cardiovascular, oncological, metabolic, autoimmune, and neurodegenerative disorders. The safety and effectiveness of the joint delivery of therapeutic genes in multicistronic vectors based on the internal ribosome entry site (IRES) and self-cleaving 2A peptides have been shown in both in vitro and in vivo experiments as well as in clinical trials. Co-expression of several genes in one vector has also been used to create animal models of various inherited diseases which are caused by mutations in several genes. Multicistronic vectors provide expression of all mutant genes, which allows the most complete mimicking disease pathogenesis. This review comprehensively discusses multicistronic vectors based on IRES nucleotide sequence and self-cleaving 2A peptides, including its features and possible application for the treatment and modeling of various human diseases.
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23
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Zhang Y, Zhang Y, Liu Z, Cheng M, Ma J, Wang Y, Qin C, Fang X. Long non-coding subgenomic flavivirus RNAs have extended 3D structures and are flexible in solution. EMBO Rep 2019; 20:e47016. [PMID: 31502753 PMCID: PMC6832101 DOI: 10.15252/embr.201847016] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 08/14/2019] [Accepted: 08/21/2019] [Indexed: 01/05/2023] Open
Abstract
Most mosquito-borne flaviviruses, including Zika virus (ZIKV), Dengue virus (DENV), and West Nile virus (WNV), produce long non-coding subgenomic RNAs (sfRNAs) in infected cells that link to pathogenicity and immune evasion. Until now, the structural characterization of these lncRNAs remains limited. Here, we studied the 3D structures of individual and combined subdomains of sfRNAs, and visualized the accessible 3D conformational spaces of complete sfRNAs from DENV2, ZIKV, and WNV by small angle X-ray scattering (SAXS) and computational modeling. The individual xrRNA1s and xrRNA2s adopt similar structures in solution as the crystal structure of ZIKV xrRNA1, and all xrRNA1-2s form compact structures with reduced flexibility. While the DB12 of DENV2 is extended, the DB12s of ZIKV and WNV are compact due to the formation of intertwined double pseudoknots. All 3' stem-loops (3'SLs) share similar rod-like structures. Complete sfRNAs are extended and sample a large conformational space in solution. Our work not only provides structural insight into the function of flavivirus sfRNAs, but also highlights strategies of visualizing other lncRNAs in solution by SAXS and computational methods.
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Affiliation(s)
- Yupeng Zhang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Yikan Zhang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Zhong‐Yu Liu
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
- Guangzhou Eighth People's HospitalGuangzhou Medical UniversityGuangzhouChina
- School of Medicine (Shenzhen)Sun Yat‐sen UniversityGuangzhouChina
| | - Meng‐Li Cheng
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
| | - Junfeng Ma
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Yan Wang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
| | - Cheng‐Feng Qin
- State Key Laboratory of Pathogen and BiosecurityBeijing Institute of Microbiology and EpidemiologyBeijingChina
| | - Xianyang Fang
- Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijingChina
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24
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Johnson AG, Petrov AN, Fuchs G, Majzoub K, Grosely R, Choi J, Puglisi JD. Fluorescently-tagged human eIF3 for single-molecule spectroscopy. Nucleic Acids Res 2019; 46:e8. [PMID: 29136179 PMCID: PMC5778468 DOI: 10.1093/nar/gkx1050] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 01/09/2023] Open
Abstract
Human translation initiation relies on the combined activities of numerous ribosome-associated eukaryotic initiation factors (eIFs). The largest factor, eIF3, is an ∼800 kDa multiprotein complex that orchestrates a network of interactions with the small 40S ribosomal subunit, other eIFs, and mRNA, while participating in nearly every step of initiation. How these interactions take place during the time course of translation initiation remains unclear. Here, we describe a method for the expression and affinity purification of a fluorescently-tagged eIF3 from human cells. The tagged eIF3 dodecamer is structurally intact, functions in cell-based assays, and interacts with the HCV IRES mRNA and the 40S-IRES complex in vitro. By tracking the binding of single eIF3 molecules to the HCV IRES RNA with a zero-mode waveguides-based instrument, we show that eIF3 samples both wild-type IRES and an IRES that lacks the eIF3-binding region, and that the high-affinity eIF3-IRES interaction is largely determined by slow dissociation kinetics. The application of single-molecule methods to more complex systems involving eIF3 may unveil dynamics underlying mRNA selection and ribosome loading during human translation initiation.
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Affiliation(s)
- Alex G Johnson
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA.,Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexey N Petrov
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Gabriele Fuchs
- The RNA Institute, Department of Biological Sciences, University of Albany, Albany, NY 12222, USA
| | - Karim Majzoub
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Junhong Choi
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
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25
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Abstract
Hepatitis C virus represents a global pathogen of human health significance. In the space of less than three decades, we have witnessed the discovery of the virus, a growing understanding of the structure and biology of the viral-encoded proteins and their interaction with the host cell and the sequencing of the viral genome. Most importantly, we have moved from early therapeutic strategies aimed at crude boosting of host anti-viral immunity, limited by side effects and with poor response rates, to therapies that directly exploit our understanding of viral biology. In this review, we discuss the significance of the virus, its' discovery and outline the advances in the molecular characterisation of the virus, before setting these within the context of contemporary and emerging therapeutic strategies as well as viral resistance mechanisms.
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26
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Frezza E, Lavery R. Internal Coordinate Normal Mode Analysis: A Strategy To Predict Protein Conformational Transitions. J Phys Chem B 2019; 123:1294-1301. [DOI: 10.1021/acs.jpcb.8b11913] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Elisa Frezza
- MMSB, UMR 5086 CNRS/Univ. Lyon I, Institut de Biologie et Chimie des Protéines, 7 passage du Vercors, Lyon 69367, France
| | - Richard Lavery
- MMSB, UMR 5086 CNRS/Univ. Lyon I, Institut de Biologie et Chimie des Protéines, 7 passage du Vercors, Lyon 69367, France
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27
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018. [PMID: 30564270 DOI: 10.3389/fgene.2018.00595/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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28
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018; 9:595. [PMID: 30564270 PMCID: PMC6288177 DOI: 10.3389/fgene.2018.00595] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/15/2018] [Indexed: 12/11/2022] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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29
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Lozano G, Francisco-Velilla R, Martinez-Salas E. Deconstructing internal ribosome entry site elements: an update of structural motifs and functional divergences. Open Biol 2018; 8:rsob.180155. [PMID: 30487301 PMCID: PMC6282068 DOI: 10.1098/rsob.180155] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/30/2018] [Indexed: 12/16/2022] Open
Abstract
Beyond the general cap-dependent translation initiation, eukaryotic organisms use alternative mechanisms to initiate protein synthesis. Internal ribosome entry site (IRES) elements are cis-acting RNA regions that promote internal initiation of translation using a cap-independent mechanism. However, their lack of primary sequence and secondary RNA structure conservation, as well as the diversity of host factor requirement to recruit the ribosomal subunits, suggest distinct types of IRES elements. In spite of this heterogeneity, conserved motifs preserve sequences impacting on RNA structure and RNA–protein interactions important for IRES-driven translation. This conservation brings the question of whether IRES elements could consist of basic building blocks, which upon evolutionary selection result in functional elements with different properties. Although RNA-binding proteins (RBPs) perform a crucial role in the assembly of ribonucleoprotein complexes, the versatility and plasticity of RNA molecules, together with their high flexibility and dynamism, determines formation of macromolecular complexes in response to different signals. These properties rely on the presence of short RNA motifs, which operate as modular entities, and suggest that decomposition of IRES elements in short modules could help to understand the different mechanisms driven by these regulatory elements. Here we will review evidence suggesting that model IRES elements consist of the combination of short modules, providing sites of interaction for ribosome subunits, eIFs and RBPs, with implications for definition of criteria to identify novel IRES-like elements genome wide.
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Affiliation(s)
- Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
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30
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Bentley K, Cook JP, Tuplin AK, Evans DJ. Structural and functional analysis of the roles of the HCV 5' NCR miR122-dependent long-range association and SLVI in genome translation and replication. PeerJ 2018; 6:e5870. [PMID: 30416884 PMCID: PMC6225842 DOI: 10.7717/peerj.5870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/30/2018] [Indexed: 11/29/2022] Open
Abstract
The hepatitis C virus RNA genome possesses a variety of conserved structural elements, in both coding and non-coding regions, that are important for viral replication. These elements are known or predicted to modulate key life cycle events, such as translation and genome replication, some involving conformational changes induced by long-range RNA–RNA interactions. One such element is SLVI, a stem-loop (SL) structure located towards the 5′ end of the core protein-coding region. This element forms an alternative RNA–RNA interaction with complementary sequences in the 5′ untranslated regions that are independently involved in the binding of the cellular microRNA 122 (miR122). The switch between ‘open’ and ‘closed’ structures involving SLVI has previously been proposed to modulate translation, with lower translation efficiency associated with the ‘closed’ conformation. In the current study, we have used selective 2′-hydroxyl acylation analysed by primer extension to validate this RNA–RNA interaction in the absence and presence of miR122. We show that the long-range association (LRA) only forms in the absence of miR122, or otherwise requires the blocking of miR122 binding combined with substantial disruption of SLVI. Using site-directed mutations introduced to promote open or closed conformations of the LRA we demonstrate no correlation between the conformation and the translation phenotype. In addition, we observed no influence on virus replication compared to unmodified genomes. The presence of SLVI is well-documented to suppress translation, but these studies demonstrate that this is not due to its contribution to the LRA. We conclude that, although there are roles for SLVI in translation, the LRA is not a riboswitch regulating the translation and replication phenotypes of the virus.
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Affiliation(s)
- Kirsten Bentley
- BSRC and School of Biology, University of St Andrews, St Andrews, UK
| | - Jonathan P Cook
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Andrew K Tuplin
- The Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - David J Evans
- BSRC and School of Biology, University of St Andrews, St Andrews, UK
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Schult P, Roth H, Adams RL, Mas C, Imbert L, Orlik C, Ruggieri A, Pyle AM, Lohmann V. microRNA-122 amplifies hepatitis C virus translation by shaping the structure of the internal ribosomal entry site. Nat Commun 2018; 9:2613. [PMID: 29973597 PMCID: PMC6031695 DOI: 10.1038/s41467-018-05053-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 06/11/2018] [Indexed: 12/24/2022] Open
Abstract
The liver-specific microRNA-122 (miR-122) recognizes two conserved sites at the 5′ end of the hepatitis C virus (HCV) genome and contributes to stability, translation, and replication of the viral RNA. We show that stimulation of the HCV internal ribosome entry site (IRES) by miR-122 is essential for efficient viral replication. The mechanism relies on a dual function of the 5′ terminal sequence in the complementary positive (translation) and negative strand (replication), requiring different secondary structures. Predictions and experimental evidence argue for several alternative folds involving the miR-binding region (MBR) adjacent to the IRES and interfering with its function. Mutations in the MBR, designed to suppress these dysfunctional structures indeed stimulate translation independently of miR-122. Conversely, MBR mutants favoring alternative folds show impaired IRES activity. Our results therefore suggest that miR-122 binding assists the folding of a functional IRES in an RNA chaperone-like manner by suppressing energetically favorable alternative secondary structures. The liver-specific microRNA-122 is an essential proviral host factor of Hepatitis C virus replication. Here the authors show that microRNA-122 functions as an RNA chaperone that guides the formation of a functional internal ribosome entry site by preventing energetically more favorable secondary structures within the HCV RNA genome.
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Affiliation(s)
- Philipp Schult
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany
| | - Hanna Roth
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany
| | - Rebecca L Adams
- Department of Molecular, Cellular and Developmental Biology, Yale University, 219 Prospect St, New Haven, CT, 06511, USA
| | - Caroline Mas
- University Grenoble Alpes, CNRS, CEA, IBS, 71 Avenue des Martyrs, CS 10090, 38044, Grenoble CEDEX 9, France
| | - Lionel Imbert
- University Grenoble Alpes, CNRS, CEA, IBS, 71 Avenue des Martyrs, CS 10090, 38044, Grenoble CEDEX 9, France
| | - Christian Orlik
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany.,Department of Immunology, Molecular Immunology, University of Heidelberg, 69120, Heidelberg, Germany
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany
| | - Anna M Pyle
- Department of Molecular, Cellular and Developmental Biology, Yale University, 219 Prospect St, New Haven, CT, 06511, USA.,Howard Hughes Medical Institute, 219 Prospect St, New Haven, CT, 06511, USA
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany.
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Roles of the 5' Untranslated Region of Nonprimate Hepacivirus in Translation Initiation and Viral Replication. J Virol 2018; 92:JVI.01997-17. [PMID: 29343570 DOI: 10.1128/jvi.01997-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/09/2018] [Indexed: 12/26/2022] Open
Abstract
The 5' untranslated region (UTR) of hepatitis C virus (HCV), which is composed of four domains (I, II, III, and IV) and a pseudoknot, is essential for translation and viral replication. Equine nonprimate hepacivirus (EHcV) harbors a 5' UTR consisting of a large 5'-terminal domain (I); three additional domains (I', II, and III), which are homologous to domains I, II, and III, respectively, of HCV; and a pseudoknot, in the order listed. In this study, we investigated the roles of the EHcV 5' UTR in translation and viral replication. The internal ribosome entry site (IRES) activity of the EHcV 5' UTR was lower than that of the HCV 5' UTR in several cell lines due to structural differences in domain III. Domains I and III of EHcV were functional in the HCV 5' UTR in terms of IRES activity and the replication of the subgenomic replicon (SGR), although domain II was not exchangeable between EHcV and HCV for SGR replication. Furthermore, the region spanning domains I and I' of EHcV (the 5'-proximal EHcV-specific region) improved RNA stability and provided the HCV SGR with microRNA 122 (miR-122)-independent replication capability, while EHcV domain I alone improved SGR replication and RNA stability irrespective of miR-122. These data suggest that the region spanning EHcV domains I and I' improves RNA stability and viral replication regardless of miR-122 expression. The 5'-proximal EHcV-specific region may represent an inherent mechanism to facilitate viral replication in nonhepatic tissues.IMPORTANCE EHcV is the closest viral homolog to HCV among other hepaciviruses. HCV exhibits a narrow host range and liver-specific tropism, while epidemiological reports suggest that EHcV infects the liver and respiratory organs in horses, donkeys, and dogs. However, the mechanism explaining the differences in host or organ tropism between HCV and EHcV is unknown. In this study, our data suggest that the 5' untranslated region (UTR) of EHcV is composed of an internal ribosome entry site (IRES) element that is functionally exchangeable with HCV IRES elements. Furthermore, the 5'-proximal EHcV-specific region enhances viral replication and RNA stability in a miR-122-independent manner. Our data suggest that the region upstream of domain II in the EHcV 5' UTR contributes to the differences in tissue tropism observed between these hepaciviruses.
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Mailliot J, Martin F. Viral internal ribosomal entry sites: four classes for one goal. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9. [PMID: 29193740 DOI: 10.1002/wrna.1458] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/19/2017] [Accepted: 10/02/2017] [Indexed: 12/22/2022]
Abstract
To ensure efficient propagation, viruses need to rapidly produce viral proteins after cell entrance. Since viral genomes do not encode any components of the protein biosynthesis machinery, viral proteins must be produced by the host cell. To hi-jack the host cellular translation, viruses use a great variety of distinct strategies. Many single-stranded positive-sensed RNA viruses contain so-called internal ribosome entry sites (IRESs). IRESs are structural RNA motifs that have evolved to specific folds that recruit the host ribosomes on the viral coding sequences in order to synthesize viral proteins. In host canonical translation, recruitment of the translation machinery components is essentially guided by the 5' cap (m7 G) of mRNA. In contrast, IRESs are able to promote efficient ribosome assembly internally and in cap-independent manner. IRESs have been categorized into four classes, based on their length, nucleotide sequence, secondary and tertiary structures, as well as their mode of action. Classes I and II require the assistance of cellular auxiliary factors, the eukaryotic intiation factors (eIF), for efficient ribosome assembly. Class III IRESs require only a subset of eIFs whereas Class IV, which are the more compact, can promote translation without any eIFs. Extensive functional and structural investigations of IRESs over the past decades have allowed a better understanding of their mode of action for viral translation. Because viral translation has a pivotal role in the infectious program, IRESs are therefore attractive targets for therapeutic purposes. WIREs RNA 2018, 9:e1458. doi: 10.1002/wrna.1458 This article is categorized under: Translation > Ribosome Structure/Function Translation > Translation Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Justine Mailliot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Illkirch-Graffenstaden, France
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN" CNRS UPR9002, Université De Strasbourg, Strasbourg, France
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Martinez-Salas E, Francisco-Velilla R, Fernandez-Chamorro J, Embarek AM. Insights into Structural and Mechanistic Features of Viral IRES Elements. Front Microbiol 2018; 8:2629. [PMID: 29354113 PMCID: PMC5759354 DOI: 10.3389/fmicb.2017.02629] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/15/2017] [Indexed: 01/19/2023] Open
Abstract
Internal ribosome entry site (IRES) elements are cis-acting RNA regions that promote internal initiation of protein synthesis using cap-independent mechanisms. However, distinct types of IRES elements present in the genome of various RNA viruses perform the same function despite lacking conservation of sequence and secondary RNA structure. Likewise, IRES elements differ in host factor requirement to recruit the ribosomal subunits. In spite of this diversity, evolutionarily conserved motifs in each family of RNA viruses preserve sequences impacting on RNA structure and RNA–protein interactions important for IRES activity. Indeed, IRES elements adopting remarkable different structural organizations contain RNA structural motifs that play an essential role in recruiting ribosomes, initiation factors and/or RNA-binding proteins using different mechanisms. Therefore, given that a universal IRES motif remains elusive, it is critical to understand how diverse structural motifs deliver functions relevant for IRES activity. This will be useful for understanding the molecular mechanisms beyond cap-independent translation, as well as the evolutionary history of these regulatory elements. Moreover, it could improve the accuracy to predict IRES-like motifs hidden in genome sequences. This review summarizes recent advances on the diversity and biological relevance of RNA structural motifs for viral IRES elements.
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Affiliation(s)
- Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Azman M Embarek
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
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35
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Johnson AG, Grosely R, Petrov AN, Puglisi JD. Dynamics of IRES-mediated translation. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0177. [PMID: 28138065 DOI: 10.1098/rstb.2016.0177] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 12/19/2022] Open
Abstract
Viral internal ribosome entry sites (IRESs) are unique RNA elements, which use stable and dynamic RNA structures to recruit ribosomes and drive protein synthesis. IRESs overcome the high complexity of the canonical eukaryotic translation initiation pathway, often functioning with a limited set of eukaryotic initiation factors. The simplest types of IRESs are typified by the cricket paralysis virus intergenic region (CrPV IGR) and hepatitis C virus (HCV) IRESs, both of which independently form high-affinity complexes with the small (40S) ribosomal subunit and bypass the molecular processes of cap-binding and scanning. Owing to their simplicity and ribosomal affinity, the CrPV and HCV IRES have been important models for structural and functional studies of the eukaryotic ribosome during initiation, serving as excellent targets for recent technological breakthroughs in cryogenic electron microscopy (cryo-EM) and single-molecule analysis. High-resolution structural models of ribosome : IRES complexes, coupled with dynamics studies, have clarified decades of biochemical research and provided an outline of the conformational and compositional trajectory of the ribosome during initiation. Here we review recent progress in the study of HCV- and CrPV-type IRESs, highlighting important structural and dynamics insights and the synergy between cryo-EM and single-molecule studies.This article is part of the themed issue 'Perspectives on the ribosome'.
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Affiliation(s)
- Alex G Johnson
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA.,Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexey N Petrov
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
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36
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Romero-López C, Berzal-Herranz A. The 5BSL3.2 Functional RNA Domain Connects Distant Regions in the Hepatitis C Virus Genome. Front Microbiol 2017; 8:2093. [PMID: 29163393 PMCID: PMC5671509 DOI: 10.3389/fmicb.2017.02093] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/12/2017] [Indexed: 02/05/2023] Open
Abstract
Viral genomes are complexly folded entities that carry all the information required for the infective cycle. The nucleotide sequence of the RNA virus genome encodes proteins and functional information contained in discrete, highly conserved structural units. These so-called functional RNA domains play essential roles in the progression of infection, which requires their preservation from one generation to the next. Numerous functional RNA domains exist in the genome of the hepatitis C virus (HCV). Among them, the 5BSL3.2 domain in the cis-acting replication element (CRE) at the 3' end of the viral open reading frame has become of particular interest given its role in HCV RNA replication and as a regulator of viral protein synthesis. These functionalities are achieved via the establishment of a complex network of long-distance RNA-RNA contacts involving (at least as known to date) the highly conserved 3'X tail, the apical loop of domain IIId in the internal ribosome entry site, and/or the so-called Alt region upstream of the CRE. Changing contacts promotes the execution of different stages of the viral cycle. The 5BSL3.2 domain thus operates at the core of a system that governs the progression of HCV infection. This review summarizes our knowledge of the long-range RNA-RNA interaction network in the HCV genome, with special attention paid to the structural and functional consequences derived from the establishment of different contacts. The potential implications of such interactions in switching between the different stages of the viral cycle are discussed.
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Affiliation(s)
- Cristina Romero-López
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
| | - Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
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37
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Diaz-Toledano R, Lozano G, Martinez-Salas E. In-cell SHAPE uncovers dynamic interactions between the untranslated regions of the foot-and-mouth disease virus RNA. Nucleic Acids Res 2017; 45:1416-1432. [PMID: 28180318 PMCID: PMC5388415 DOI: 10.1093/nar/gkw795] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/26/2016] [Accepted: 08/29/2016] [Indexed: 12/14/2022] Open
Abstract
The genome of RNA viruses folds into 3D structures that include long-range RNA–RNA interactions relevant to control critical steps of the viral cycle. In particular, initiation of translation driven by the IRES element of foot-and-mouth disease virus is stimulated by the 3΄UTR. Here we sought to investigate the RNA local flexibility of the IRES element and the 3΄UTR in living cells. The SHAPE reactivity observed in vivo showed statistically significant differences compared to the free RNA, revealing protected or exposed positions within the IRES and the 3΄UTR. Importantly, the IRES local flexibility was modified in the presence of the 3΄UTR, showing significant protections at residues upstream from the functional start codon. Conversely, presence of the IRES element in cis altered the 3΄UTR local flexibility leading to an overall enhanced reactivity. Unlike the reactivity changes observed in the IRES element, the SHAPE differences of the 3΄UTR were large but not statistically significant, suggesting multiple dynamic RNA interactions. These results were supported by covariation analysis, which predicted IRES-3΄UTR conserved helices in agreement with the protections observed by SHAPE probing. Mutational analysis suggested that disruption of one of these interactions could be compensated by alternative base pairings, providing direct evidences for dynamic long-range interactions between these distant elements of the viral genome.
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Affiliation(s)
- Rosa Diaz-Toledano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid, Spain
| | - Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, Madrid, Spain
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38
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Yamamoto H, Unbehaun A, Spahn CMT. Ribosomal Chamber Music: Toward an Understanding of IRES Mechanisms. Trends Biochem Sci 2017; 42:655-668. [PMID: 28684008 DOI: 10.1016/j.tibs.2017.06.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 12/31/2022]
Abstract
Internal initiation is a 5'-end-independent mode of translation initiation engaged by many virus- and putatively some cell-encoded templates. Internal initiation is facilitated by specific RNA tertiary folds, called internal ribosomal entry sites (IRESs), in the 5' untranslated region (UTR) of the respective transcripts. In this review we discuss recent structural insight into how established IRESs first capture and then manipulate the eukaryotic translation machinery through non-canonical interactions and by guiding the intrinsic conformational flexibility of the eukaryotic ribosome. Because IRESs operate with reduced complexity and constitute minimal systems of initiation, comparison with canonical initiation may allow common mechanistic principles of the ribosome to be delineated.
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Affiliation(s)
- Hiroshi Yamamoto
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany
| | - Anett Unbehaun
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian M T Spahn
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany.
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39
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Plumridge A, Meisburger SP, Pollack L. Visualizing single-stranded nucleic acids in solution. Nucleic Acids Res 2017; 45:e66. [PMID: 28034955 PMCID: PMC5435967 DOI: 10.1093/nar/gkw1297] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/09/2016] [Accepted: 12/13/2016] [Indexed: 02/06/2023] Open
Abstract
Single-stranded nucleic acids (ssNAs) are ubiquitous in many key cellular functions. Their flexibility limits both the number of high-resolution structures available, leaving only a small number of protein-ssNA crystal structures, while forcing solution investigations to report ensemble averages. A description of the conformational distributions of ssNAs is essential to more fully characterize biologically relevant interactions. We combine small angle X-ray scattering (SAXS) with ensemble-optimization methods (EOM) to dynamically build and refine sets of ssNA structures. By constructing candidate chains in representative dinucleotide steps and refining the models against SAXS data, a broad array of structures can be obtained to match varying solution conditions and strand sequences. In addition to the distribution of large scale structural parameters, this approach reveals, for the first time, intricate details of the phosphate backbone and underlying strand conformations. Such information on unperturbed strands will critically inform a detailed understanding of an array of problems including protein-ssNA binding, RNA folding and the polymer nature of NAs. In addition, this scheme, which couples EOM selection with an iteratively refining pool to give confidence in the underlying structures, is likely extendable to the study of other flexible systems.
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Affiliation(s)
- Alex Plumridge
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | | | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
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40
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Functional RNA structures throughout the Hepatitis C Virus genome. Curr Opin Virol 2017; 24:79-86. [PMID: 28511116 DOI: 10.1016/j.coviro.2017.04.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/21/2017] [Indexed: 12/18/2022]
Abstract
The single-stranded Hepatitis C Virus (HCV) genome adopts a set of elaborate RNA structures that are involved in every stage of the viral lifecycle. Recent advances in chemical probing, sequencing, and structural biology have facilitated analysis of RNA folding on a genome-wide scale, revealing novel structures and networks of interactions. These studies have underscored the active role played by RNA in every function of HCV and they open the door to new types of RNA-targeted therapeutics.
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41
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Ganesan A, Barakat K. Applications of computer-aided approaches in the development of hepatitis C antiviral agents. Expert Opin Drug Discov 2017; 12:407-425. [PMID: 28164720 DOI: 10.1080/17460441.2017.1291628] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Hepatitis C virus (HCV) is a global health problem that causes several chronic life-threatening liver diseases. The numbers of people affected by HCV are rising annually. Since 2011, the FDA has approved several anti-HCV drugs; while many other promising HCV drugs are currently in late clinical trials. Areas covered: This review discusses the applications of different computational approaches in HCV drug design. Expert opinion: Molecular docking and virtual screening approaches have emerged as a low-cost tool to screen large databases and identify potential small-molecule hits against HCV targets. Ligand-based approaches are useful for filtering-out compounds with rich physicochemical properties to inhibit HCV targets. Molecular dynamics (MD) remains a useful tool in optimizing the ligand-protein complexes and understand the ligand binding modes and drug resistance mechanisms in HCV. Despite their varied roles, the application of in-silico approaches in HCV drug design is still in its infancy. A more mature application should aim at modelling the whole HCV replicon in its active form and help to identify new effective druggable sites within the replicon system. With more technological advancements, the roles of computer-aided methods are only going to increase several folds in the development of next-generation HCV drugs.
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Affiliation(s)
- Aravindhan Ganesan
- a Faculty of Pharmacy and Pharmaceutical Sciences , University of Alberta , Edmonton , Canada
| | - Khaled Barakat
- a Faculty of Pharmacy and Pharmaceutical Sciences , University of Alberta , Edmonton , Canada
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Borgia G, Maraolo AE, Buonomo AR, Scotto R, Gentile I. The therapeutic potential of new investigational hepatitis C virus translation inhibitors. Expert Opin Investig Drugs 2016; 25:1209-14. [PMID: 27537604 DOI: 10.1080/13543784.2016.1225036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Hepatitis C virus (HCV) infection is a leading cause of liver cirrhosis, hepatocellular carcinoma and liver-related death worldwide. Currently, the anti-HCV armamentarium encompasses several direct-acting antivirals (DAA) that achieve very high response rates and have an excellent tolerability profile. However, they do not represent a final solution for HCV global eradication for at least these two reasons: i) some patients harbour resistant strains to DAAs and cannot benefit from currently available treatments; ii) the cost of these drugs remains very high. AREAS COVERED This review summarizes pre-clinical and clinical data regarding HCV translation inhibitors, a new class of drugs currently in the pipeline with novel mechanisms of action. EXPERT OPINION The availability of DAAs resolved most issues related to HCV treatment compared with the previous interferon-based therapies. However, there are some patients that cannot achieve a viral clearance with currently available treatments. Therefore, there is still room for new drugs in this setting, providing that they demonstrate an advantage in terms of efficacy, safety, cost or or simplicity of use. Based on preliminary results, at least for some promising molecules (e.g. miravirsen and RG-101), studies on safety and efficacy on this intriguing class of drugs are needed.
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Affiliation(s)
- Guglielmo Borgia
- a Department of Clinical Medicine and Surgery , University of Naples 'Federico II,' Naples , Italy
| | - Alberto Enrico Maraolo
- a Department of Clinical Medicine and Surgery , University of Naples 'Federico II,' Naples , Italy
| | - Antonio Riccardo Buonomo
- a Department of Clinical Medicine and Surgery , University of Naples 'Federico II,' Naples , Italy
| | - Riccardo Scotto
- a Department of Clinical Medicine and Surgery , University of Naples 'Federico II,' Naples , Italy
| | - Ivan Gentile
- a Department of Clinical Medicine and Surgery , University of Naples 'Federico II,' Naples , Italy
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Yabukarski F, Leyrat C, Martinez N, Communie G, Ivanov I, Ribeiro EA, Buisson M, Gerard FC, Bourhis JM, Jensen MR, Bernadó P, Blackledge M, Jamin M. Ensemble Structure of the Highly Flexible Complex Formed between Vesicular Stomatitis Virus Unassembled Nucleoprotein and its Phosphoprotein Chaperone. J Mol Biol 2016; 428:2671-94. [PMID: 27107640 DOI: 10.1016/j.jmb.2016.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 01/08/2023]
Abstract
Nucleocapsid assembly is an essential process in the replication of the non-segmented, negative-sense RNA viruses (NNVs). Unassembled nucleoprotein (N(0)) is maintained in an RNA-free and monomeric form by its viral chaperone, the phosphoprotein (P), forming the N(0)-P complex. Our earlier work solved the structure of vesicular stomatitis virus complex formed between an N-terminally truncated N (NΔ21) and a peptide of P (P60) encompassing the N(0)-binding site, but how the full-length P interacts with N(0) remained unknown. Here, we combine several experimental biophysical methods including size exclusion chromatography with detection by light scattering and refractometry, small-angle X-ray and neutron scattering and nuclear magnetic resonance spectroscopy with molecular dynamics simulation and computational modeling to characterize the NΔ21(0)-PFL complex formed with dimeric full-length P. We show that for multi-molecular complexes, simultaneous multiple-curve fitting using small-angle neutron scattering data collected at varying contrast levels provides additional information and can help refine structural ensembles. We demonstrate that (a) vesicular stomatitis virus PFL conserves its high flexibility within the NΔ21(0)-PFL complex and interacts with NΔ21(0) only through its N-terminal extremity; (b) each protomer of P can chaperone one N(0) client protein, leading to the formation of complexes with stoichiometries 1N:P2 and 2N:P2; and (c) phosphorylation of residues Ser60, Thr62 and Ser64 provides no additional interactions with N(0) but creates a metal binding site in PNTR. A comparison with the structures of Nipah virus and Ebola virus N(0)-P core complex suggests a mechanism for the control of nucleocapsid assembly that is common to all NNVs.
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Affiliation(s)
- Filip Yabukarski
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Cedric Leyrat
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Nicolas Martinez
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France; Institut Laue Langevin, Grenoble, France
| | - Guillaume Communie
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Ivan Ivanov
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France; Institut Laue Langevin, Grenoble, France
| | - Euripedes A Ribeiro
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Marlyse Buisson
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France; Laboratoire de Virologie, Centre Hospitalo-Universitaire de Grenoble, Grenoble, France
| | - Francine C Gerard
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Jean-Marie Bourhis
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Malene Ringkjøbing Jensen
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Pau Bernadó
- Centre de Biochimie Structurale, INSERM U1054, CNRS UMR 5048, Université Montpellier 1 and 2, Montpellier, France
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France
| | - Marc Jamin
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, Grenoble 38044, France.
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Chen Y, Pollack L. SAXS studies of RNA: structures, dynamics, and interactions with partners. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:512-26. [PMID: 27071649 DOI: 10.1002/wrna.1349] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/11/2016] [Accepted: 03/01/2016] [Indexed: 12/29/2022]
Abstract
Small-angle X-ray scattering, SAXS, is a powerful and easily employed experimental technique that provides solution structures of macromolecules. The size and shape parameters derived from SAXS provide global structural information about these molecules in solution and essentially complement data acquired by other biophysical methods. As applied to protein systems, SAXS is a relatively mature technology: sophisticated tools exist to acquire and analyze data, and to create structural models that include dynamically flexible ensembles. Given the expanding appreciation of RNA's biological roles, there is a need to develop comparable tools to characterize solution structures of RNA, including its interactions with important biological partners. We review the progress toward achieving this goal, focusing on experimental and computational innovations. The use of multiphase modeling, absolute calibration and contrast variation methods, among others, provides new and often unique ways of visualizing this important biological molecule and its essential partners: ions, other RNAs, or proteins. WIREs RNA 2016, 7:512-526. doi: 10.1002/wrna.1349 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Yujie Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
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Designing synthetic RNAs to determine the relevance of structural motifs in picornavirus IRES elements. Sci Rep 2016; 6:24243. [PMID: 27053355 PMCID: PMC4823658 DOI: 10.1038/srep24243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/23/2016] [Indexed: 12/22/2022] Open
Abstract
The function of Internal Ribosome Entry Site (IRES) elements is intimately linked to their RNA structure. Viral IRES elements are organized in modular domains consisting of one or more stem-loops that harbor conserved RNA motifs critical for internal initiation of translation. A conserved motif is the pyrimidine-tract located upstream of the functional initiation codon in type I and II picornavirus IRES. By computationally designing synthetic RNAs to fold into a structure that sequesters the polypyrimidine tract in a hairpin, we establish a correlation between predicted inaccessibility of the pyrimidine tract and IRES activity, as determined in both in vitro and in vivo systems. Our data supports the hypothesis that structural sequestration of the pyrimidine-tract within a stable hairpin inactivates IRES activity, since the stronger the stability of the hairpin the higher the inhibition of protein synthesis. Destabilization of the stem-loop immediately upstream of the pyrimidine-tract also decreases IRES activity. Our work introduces a hybrid computational/experimental method to determine the importance of structural motifs for biological function. Specifically, we show the feasibility of using the software RNAiFold to design synthetic RNAs with particular sequence and structural motifs that permit subsequent experimental determination of the importance of such motifs for biological function.
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Pérard J, Covès J, Castellan M, Solard C, Savard M, Miras R, Galop S, Signor L, Crouzy S, Michaud-Soret I, de Rosny E. Quaternary Structure of Fur Proteins, a New Subfamily of Tetrameric Proteins. Biochemistry 2016; 55:1503-15. [DOI: 10.1021/acs.biochem.5b01061] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Julien Pérard
- CNRS, Laboratoire de Chimie et Biologie
des Métaux
(LCBM), UMR 5249, CNRS-CEA-UJF, F-38054 Grenoble, France
- CEA, LCBM, F-38054 Grenoble, France
- Univ. Grenoble Alpes, LCBM, F-38054 Grenoble, France
| | - Jacques Covès
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Mathieu Castellan
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Charles Solard
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Myriam Savard
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Roger Miras
- CNRS, Laboratoire de Chimie et Biologie
des Métaux
(LCBM), UMR 5249, CNRS-CEA-UJF, F-38054 Grenoble, France
- CEA, LCBM, F-38054 Grenoble, France
- Univ. Grenoble Alpes, LCBM, F-38054 Grenoble, France
| | - Sandra Galop
- CNRS, Laboratoire de Chimie et Biologie
des Métaux
(LCBM), UMR 5249, CNRS-CEA-UJF, F-38054 Grenoble, France
- CEA, LCBM, F-38054 Grenoble, France
- Univ. Grenoble Alpes, LCBM, F-38054 Grenoble, France
| | - Luca Signor
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Serge Crouzy
- CNRS, Laboratoire de Chimie et Biologie
des Métaux
(LCBM), UMR 5249, CNRS-CEA-UJF, F-38054 Grenoble, France
- CEA, LCBM, F-38054 Grenoble, France
- Univ. Grenoble Alpes, LCBM, F-38054 Grenoble, France
| | - Isabelle Michaud-Soret
- CNRS, Laboratoire de Chimie et Biologie
des Métaux
(LCBM), UMR 5249, CNRS-CEA-UJF, F-38054 Grenoble, France
- CEA, LCBM, F-38054 Grenoble, France
- Univ. Grenoble Alpes, LCBM, F-38054 Grenoble, France
| | - Eve de Rosny
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
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Lozano G, Jimenez-Aparicio R, Herrero S, Martinez-Salas E. Fingerprinting the junctions of RNA structure by an open-paddlewheel diruthenium compound. RNA (NEW YORK, N.Y.) 2016; 22:330-8. [PMID: 26759454 PMCID: PMC4748811 DOI: 10.1261/rna.054353.115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/05/2015] [Indexed: 05/17/2023]
Abstract
RNA function is determined by its structural organization. The RNA structure consists of the combination of distinct secondary structure motifs connected by junctions that play an essential role in RNA folding. Selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) probing is an established methodology to analyze the secondary structure of long RNA molecules in solution, which provides accurate data about unpaired nucleotides. However, the residues located at the junctions of RNA structures usually remain undetected. Here we report an RNA probing method based on the use of a novel open-paddlewheel diruthenium (OPW-Ru) compound [Ru2Cl2(µ-DPhF)3(DMSO)] (DPhF = N,N'-diphenylformamidinate). This compound has four potential coordination sites in a singular disposition to establish covalent bonds with substrates. As a proof of concept, we have analyzed the reactivity of OPW-Ru toward RNA using two viral internal ribosome entry site (IRES) elements whose function depends on the structural organization of the molecule. Our study suggests that the compound OPW-Ru preferentially attacks at positions located one or two nucleotides away from junctions or bulges of the RNA structure. The OPW-Ru fingerprinting data differ from that obtained by other chemical reagents and provides new information about RNA structure features.
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Affiliation(s)
- Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid 28049, Spain
| | - Reyes Jimenez-Aparicio
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Santiago Herrero
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid 28040, Spain
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Lozano G, Fernandez N, Martinez-Salas E. Modeling Three-Dimensional Structural Motifs of Viral IRES. J Mol Biol 2016; 428:767-776. [PMID: 26778619 DOI: 10.1016/j.jmb.2016.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 01/23/2023]
Abstract
RNA virus genomes are reservoirs of a wide diversity of RNA structural elements. In particular, specific regions of the viral genome have evolved to adopt specialized three-dimensional (3D) structures, which can act in concert with host factors and/or viral proteins to recruit the translation machinery on viral RNA using a mechanism that is independent on the 5' end. This strategy relies on cis-acting RNA sequences designated as internal ribosome entry site (IRES) elements. IRES elements that are found in the genome of different groups of RNA viruses perform the same function despite differing in primary sequence and secondary RNA structure and host factor requirement to recruit the translation machinery internally. Evolutionarily conserved motifs tend to preserve sequences in each group of RNA viruses impacting on RNA structure and RNA-protein interactions important for IRES function. However, due to the lack of sequence homology among genetically distant IRES elements, accurate modeling of 3D IRES structure is currently a challenging task. In addition, as a universal RNA motif unique to IRES elements has not been found, a better understanding of viral IRES structural motifs could greatly assist in the detection of IRES-like motifs hidden in genome sequences. The focus of this review is to describe recent advances in modeling viral IRES tertiary structural motifs and also novel approaches to detect sequences potentially folding as IRES-like motifs.
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Affiliation(s)
- Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Noemi Fernandez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain.
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Moon JS, Lee SH, Kim EJ, Cho H, Lee W, Kim GW, Park HJ, Cho SW, Lee C, Oh JW. Inhibition of Hepatitis C Virus in Mice by a Small Interfering RNA Targeting a Highly Conserved Sequence in Viral IRES Pseudoknot. PLoS One 2016; 11:e0146710. [PMID: 26751678 PMCID: PMC4713436 DOI: 10.1371/journal.pone.0146710] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/21/2015] [Indexed: 02/07/2023] Open
Abstract
The hepatitis C virus (HCV) internal ribosome entry site (IRES) that directs cap-independent viral translation is a primary target for small interfering RNA (siRNA)-based HCV antiviral therapy. However, identification of potent siRNAs against HCV IRES by bioinformatics-based siRNA design is a challenging task given the complexity of HCV IRES secondary and tertiary structures and association with multiple proteins, which can also dynamically change the structure of this cis-acting RNA element. In this work, we utilized siRNA tiling approach whereby siRNAs were tiled with overlapping sequences that were shifted by one or two nucleotides over the HCV IRES stem-loop structures III and IV spanning nucleotides (nts) 277-343. Based on their antiviral activity, we mapped a druggable region (nts 313-343) where the targets of potent siRNAs were enriched. siIE22, which showed the greatest anti-HCV potency, targeted a highly conserved sequence across diverse HCV genotypes, locating within the IRES subdomain IIIf involved in pseudoknot formation. Stepwise target shifting toward the 5' or 3' direction by 1 or 2 nucleotides reduced the antiviral potency of siIE22, demonstrating the importance of siRNA accessibility to this highly structured and sequence-conserved region of HCV IRES for RNA interference. Nanoparticle-mediated systemic delivery of the stability-improved siIE22 derivative gs_PS1 siIE22, which contains a single phosphorothioate linkage on the guide strand, reduced the serum HCV genome titer by more than 4 log10 in a xenograft mouse model for HCV replication without generation of resistant variants. Our results provide a strategy for identifying potent siRNA species against a highly structured RNA target and offer a potential pan-HCV genotypic siRNA therapy that might be beneficial for patients resistant to current treatment regimens.
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Affiliation(s)
- Jae-Su Moon
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Seung-Hoon Lee
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Eun-Jung Kim
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Hee Cho
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Wooseong Lee
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Geon-Woo Kim
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Hyun-Ji Park
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Seung-Woo Cho
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
| | - Choongho Lee
- College of Pharmacy, Dongguk University, Goyang 410–820, Korea
| | - Jong-Won Oh
- Department of Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120–749, Korea
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Ross MJ, Bradford SS, Cowan JA. Catalytic metallodrugs based on the LaR2C peptide target HCV SLIV IRES RNA. Dalton Trans 2015; 44:20972-82. [PMID: 26583601 PMCID: PMC4691540 DOI: 10.1039/c5dt02837j] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Prior work has demonstrated the potential effectiveness of a new class of metallopeptides as catalytic metallodrugs that target HCV IRES SLIIb RNA (Cu-GGHYrFK, 1). Herein new catalytic metallodrugs (GGHKYKETDLLILFKDDYFAKKNEERK, 2; and GGHKYKETDL, 3) are described based on the LaR2C peptide that has been shown to bind to the SLIV HCV IRES domain. In vitro fluorescence assays yielded KD values ∼10 μM for both peptides and reaction of the copper derivatives with SLIV RNA demonstrated initial rates comparable across different assays as well as displaying pseudo-Michaelis-Menten behavior. The sites of reaction and cleavage mechanisms were determined by MALDI-TOF mass spectrometry. The primary site of copper-promoted SLIV cleavage is shown to occur in the vicinity of the 5'-G17C18A19C20-3' sequence that corresponds to a known binding site of the RM2 motif of the human La protein and has previously been reported to be important for viral translation. This domain also flanks the internal start codon (AUG). Both copper complexes also showed efficacy in an HCV replicon assay (IC50 = 0.75 μM for 2-Cu, and 2.17 μM for 3-Cu) and show potential for treatment of hepatitis C, complementing other marketed drugs by acting on a distinct therapeutic target by a novel mechanism of action.
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Affiliation(s)
- Martin James Ross
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Seth S. Bradford
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - J. A. Cowan
- Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
- MetalloPharm, 1790 Riverstone Dr., Delaware, OH 43015
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