101
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Mapping the RNA structural landscape of viral genomes. Methods 2019; 183:57-67. [PMID: 31711930 DOI: 10.1016/j.ymeth.2019.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/13/2019] [Accepted: 11/05/2019] [Indexed: 12/26/2022] Open
Abstract
Functional RNA structures are prevalent in viral genomes, and have been shown to play roles in almost every aspect of their biology. However, the majority of viral RNA remains structurally uncharacterized. This is likely to remain true as the cost of sequencing decreases much faster than the cost of structural characterizations. Because of this, there is a need for rapid, inexpensive methods to highlight regions of viral RNA which are ideal candidates for structure-function analyses. The ScanFold method was developed as a single sequence alternative to traditional RNA structural motif discovery pipelines, which rely heavily on well curated sequence alignments to identify conserved RNA structures. ScanFold focuses on identifying (based on their more stable than expected folding energies) the most likely functional structures encoded within a single large RNA sequence, while allowing predicted motifs to be tested for evidence of structural conservation later. Decoupling these processes can be a benefit to researchers studying viruses lacking the ideal phylogenetic depth to yield evidence of structural conservation. Here, we demonstrate how the most significant ScanFold predicted structures correspond to higher base pairing probabilities, SHAPE reactivities, and predict known functional structures within the ZIKV and HIV-1 genomes with accuracy. Best practices and examples are also shown to aid users in utilizing ScanFold for their own systems of interest. ScanFold is available as a Webserver (https://mosslabtools.bb.iastate.edu/scanfold) or can be downloaded (https://github.com/moss-lab/ScanFold) and run locally.
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102
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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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103
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Evasion of Innate and Intrinsic Antiviral Pathways by the Zika Virus. Viruses 2019; 11:v11100970. [PMID: 31652496 PMCID: PMC6833475 DOI: 10.3390/v11100970] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 10/19/2019] [Accepted: 10/20/2019] [Indexed: 12/15/2022] Open
Abstract
The Zika virus (ZIKV) is a recently emerged mosquito-borne flavivirus that, while typically asymptomatic, can cause neurological symptoms in adults and birth defects in babies born to infected mothers. The interactions of ZIKV with many different pathways in the human host ultimately determine successful virus replication and ZIKV-induced pathogenesis; however, the molecular mechanisms of such host-ZIKV interactions have just begun to be elucidated. Here, we summarize the recent advances that defined the mechanisms by which ZIKV antagonizes antiviral innate immune signaling pathways, with a particular focus on evasion of the type I interferon response in the human host. Furthermore, we describe emerging evidence that indicated the contribution of several cell-intrinsic mechanisms to an effective restriction of ZIKV infection, such as nonsense-mediated mRNA decay, stress granule formation, and "reticulophagy", a type of selective autophagy. Finally, we summarize the recent work that identified strategies by which ZIKV modulated these intrinsic antiviral responses.
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104
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Ferraris P, Yssel H, Missé D. Zika virus infection: an update. Microbes Infect 2019; 21:353-360. [DOI: 10.1016/j.micinf.2019.04.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 02/07/2023]
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105
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Gunawardene CD, Newburn LR, White K. A 212-nt long RNA structure in the Tobacco necrosis virus-D RNA genome is resistant to Xrn degradation. Nucleic Acids Res 2019; 47:9329-9342. [PMID: 31392982 PMCID: PMC6755097 DOI: 10.1093/nar/gkz668] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 06/26/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022] Open
Abstract
Plus-strand RNA viruses can accumulate viral RNA degradation products during infections. Some of these decay intermediates are generated by the cytosolic 5'-to-3' exoribonuclease Xrn1 (mammals and yeast) or Xrn4 (plants) and are formed when the enzyme stalls on substrate RNAs upon encountering inhibitory RNA structures. Many Xrn-generated RNAs correspond to 3'-terminal segments within the 3'-UTR of viral genomes and perform important functions during infections. Here we have investigated a 3'-terminal small viral RNA (svRNA) generated by Xrn during infections with Tobacco necrosis virus-D (family Tombusviridae). Our results indicate that (i) unlike known stalling RNA structures that are compact and modular, the TNV-D structure encompasses the entire 212 nt of the svRNA and is not functionally transposable, (ii) at least two tertiary interactions within the RNA structure are required for effective Xrn blocking and (iii) most of the svRNA generated in infections is derived from viral polymerase-generated subgenomic mRNA1. In vitro and in vivo analyses allowed for inferences on roles for the svRNA. Our findings provide a new and distinct addition to the growing list of Xrn-resistant viral RNAs and stalling structures found associated with different plant and animal RNA viruses.
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Affiliation(s)
| | - Laura R Newburn
- Department of Biology, York University, Toronto, Ontario, M3J 1P3, Canada
| | - K Andrew White
- Department of Biology, York University, Toronto, Ontario, M3J 1P3, Canada
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106
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Michalski D, Ontiveros JG, Russo J, Charley PA, Anderson JR, Heck AM, Geiss BJ, Wilusz J. Zika virus noncoding sfRNAs sequester multiple host-derived RNA-binding proteins and modulate mRNA decay and splicing during infection. J Biol Chem 2019; 294:16282-16296. [PMID: 31519749 DOI: 10.1074/jbc.ra119.009129] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/19/2019] [Indexed: 12/17/2022] Open
Abstract
Insect-borne flaviviruses produce a 300-500-base long noncoding RNA, termed subgenomic flavivirus RNA (sfRNA), by stalling the cellular 5'-3'-exoribonuclease 1 (XRN1) via structures located in their 3' UTRs. In this study, we demonstrate that sfRNA production by Zika virus represses XRN1 analogous to what we have previously shown for other flaviviruses. Using protein-RNA reconstitution and a stringent RNA pulldown assay with human choriocarcinoma (JAR) cells, we demonstrate that the sfRNAs from both dengue type 2 and Zika viruses interact with a common set of 21 RNA-binding proteins that contribute to the regulation of post-transcriptional processes in the cell, including splicing, RNA stability, and translation. We found that four of these sfRNA-interacting host proteins, DEAD-box helicase 6 (DDX6) and enhancer of mRNA decapping 3 (EDC3) (two RNA decay factors), phosphorylated adaptor for RNA export (a regulator of the biogenesis of the splicing machinery), and apolipoprotein B mRNA-editing enzyme catalytic subunit 3C (APOBEC3C, a nucleic acid-editing deaminase), inherently restrict Zika virus infection. Furthermore, we demonstrate that the regulations of cellular mRNA decay and RNA splicing are compromised by Zika virus infection as well as by sfRNA alone. Collectively, these results reveal the large extent to which Zika virus-derived sfRNAs interact with cellular RNA-binding proteins and highlight the potential for widespread dysregulation of post-transcriptional control that likely limits the effective response of these cells to viral infection.
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Affiliation(s)
- Daniel Michalski
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - J Gustavo Ontiveros
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523
| | - Joseph Russo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Phillida A Charley
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - John R Anderson
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523
| | - Adam M Heck
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523
| | - Brian J Geiss
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523.,Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523 .,Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523
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107
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Subgenomic flavivirus RNA binds the mosquito DEAD/H-box helicase ME31B and determines Zika virus transmission by Aedes aegypti. Proc Natl Acad Sci U S A 2019; 116:19136-19144. [PMID: 31488709 DOI: 10.1073/pnas.1905617116] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Zika virus (ZIKV) is an arthropod-borne flavivirus predominantly transmitted by Aedes aegypti mosquitoes and poses a global human health threat. All flaviviruses, including those that exclusively replicate in mosquitoes, produce a highly abundant, noncoding subgenomic flavivirus RNA (sfRNA) in infected cells, which implies an important function of sfRNA during mosquito infection. Currently, the role of sfRNA in flavivirus transmission by mosquitoes is not well understood. Here, we demonstrate that an sfRNA-deficient ZIKV (ZIKVΔSF1) replicates similar to wild-type ZIKV in mosquito cell culture but is severely attenuated in transmission by Ae. aegypti after an infectious blood meal, with 5% saliva-positive mosquitoes for ZIKVΔSF1 vs. 31% for ZIKV. Furthermore, viral titers in the mosquito saliva were lower for ZIKVΔSF1 as compared to ZIKV. Comparison of mosquito infection via infectious blood meals and intrathoracic injections showed that sfRNA is important for ZIKV to overcome the mosquito midgut barrier and to promote virus accumulation in the saliva. Next-generation sequencing of infected mosquitoes showed that viral small-interfering RNAs were elevated upon ZIKVΔSF1 as compared to ZIKV infection. RNA-affinity purification followed by mass spectrometry analysis uncovered that sfRNA specifically interacts with a specific set of Ae. aegypti proteins that are normally associated with RNA turnover and protein translation. The DEAD/H-box helicase ME31B showed the highest affinity for sfRNA and displayed antiviral activity against ZIKV in Ae. aegypti cells. Based on these results, we present a mechanistic model in which sfRNA sequesters ME31B to promote flavivirus replication and virion production to facilitate transmission by mosquitoes.
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108
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Tosar JP, Gámbaro F, Darré L, Pantano S, Westhof E, Cayota A. Dimerization confers increased stability to nucleases in 5' halves from glycine and glutamic acid tRNAs. Nucleic Acids Res 2019; 46:9081-9093. [PMID: 29893896 PMCID: PMC6158491 DOI: 10.1093/nar/gky495] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/22/2018] [Indexed: 11/22/2022] Open
Abstract
We have previously shown that 5′ halves from tRNAGlyGCC and tRNAGluCUC are the most enriched small RNAs in the extracellular space of human cell lines, and especially in the non-vesicular fraction. Extracellular RNAs are believed to require protection by either encapsulation in vesicles or ribonucleoprotein complex formation. However, deproteinization of non-vesicular tRNA halves does not affect their retention in size-exclusion chromatography. Thus, we considered alternative explanations for their extracellular stability. In-silico analysis of the sequence of these tRNA-derived fragments showed that tRNAGly 5′ halves can form homodimers or heterodimers with tRNAGlu 5′ halves. This capacity is virtually unique to glycine tRNAs. By analyzing synthetic oligonucleotides by size exclusion chromatography, we provide evidence that dimerization is possible in vitro. tRNA halves with single point substitutions preventing dimerization are degraded faster both in controlled nuclease digestion assays and after transfection in cells, showing that dimerization can stabilize tRNA halves against the action of cellular nucleases. Finally, we give evidence supporting dimerization of endogenous tRNAGlyGCC 5′ halves inside cells. Considering recent reports have shown that 5′ tRNA halves from Ala and Cys can form tetramers, our results highlight RNA intermolecular structures as a new layer of complexity in the biology of tRNA-derived fragments.
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Affiliation(s)
- Juan Pablo Tosar
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo 11400, Uruguay
| | - Fabiana Gámbaro
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Nuclear Research Center, Faculty of Science, Universidad de la República, Montevideo 11400, Uruguay
| | - Leonardo Darré
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Group of Biomolecular Simulations, Institut Pasteur de Montevideo. Montevideo 11400, Uruguay
| | - Sergio Pantano
- Group of Biomolecular Simulations, Institut Pasteur de Montevideo. Montevideo 11400, Uruguay
| | - Eric Westhof
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, 15 rue René Descartes, 67084 Strasbourg, France
| | - Alfonso Cayota
- Functional Genomics Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.,Department of Medicine, Faculty of Medicine, Universidad de la República, Montevideo 11600, Uruguay
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109
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Abstract
RNA viruses encode the information required to usurp cellular metabolism and gene regulation and to enable their own replication in two ways: in the linear sequence of their RNA genomes and in higher-order structures that form when the genomic RNA strand folds back on itself. Application of high-resolution SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) structure probing to viral RNA genomes has identified numerous new regulatory elements, defined new principles by which viral RNAs interact with the cellular host and evade host immune responses, and revealed relationships between virus evolution and RNA structure. This review summarizes our current understanding of genome structure-function interrelationships for RNA viruses, as informed by SHAPE structure probing, and outlines opportunities for future studies.
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Affiliation(s)
- Mark A Boerneke
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
| | - Jeffrey E Ehrhardt
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
| | - Kevin M Weeks
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA; , ,
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110
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Abstract
The three-dimensional structures of RNA molecules provide rich and often critical information for understanding their functions, including how they recognize small molecule and protein partners. Computational modeling of RNA 3D structure is becoming increasingly accurate, particularly with the availability of growing numbers of template structures already solved experimentally and the development of sequence alignment and 3D modeling tools to take advantage of this database. For several recent "RNA puzzle" blind modeling challenges, we have successfully identified useful template structures and achieved accurate structure predictions through homology modeling tools developed in the Rosetta software suite. We describe our semi-automated methodology here and walk through two illustrative examples: an adenine riboswitch aptamer, modeled from a template guanine riboswitch structure, and a SAM I/IV riboswitch aptamer, modeled from a template SAM I riboswitch structure.
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Affiliation(s)
- Andrew M Watkins
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States
| | - Ramya Rangan
- Biophysics Program, Stanford University, Stanford, CA, United States
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States; Biophysics Program, Stanford University, Stanford, CA, United States.
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111
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Finol E, Ooi EE. Evolution of Subgenomic RNA Shapes Dengue Virus Adaptation and Epidemiological Fitness. iScience 2019; 16:94-105. [PMID: 31154208 PMCID: PMC6545344 DOI: 10.1016/j.isci.2019.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 02/02/2019] [Accepted: 05/13/2019] [Indexed: 01/07/2023] Open
Abstract
Changes in dengue virus (DENV) genome affect viral fitness both clinically and epidemiologically. Even in the 3′ untranslated region (3′ UTR), mutations could affect subgenomic flaviviral RNA (sfRNA) production and its affinity for host proteins, which are necessary for successful viral replication. Indeed, we recently showed that mutations in DENV2 3′ UTR of epidemic strains increased sfRNA ability to bind host proteins and reduce interferon expression. However, whether 3′ UTR differences shape the overall DENV evolution remains incompletely understood. Herein, we combined RNA phylogeny with phylogenetics to gain insights on sfRNA evolution. We found that sfRNA structures are under purifying selection and highly conserved despite sequence divergence. Only the second flaviviral nuclease-resistant RNA (fNR2) structure of DENV2 sfRNA has undergone strong positive selection. Epidemiological reports suggest that substitutions in fNR2 may drive DENV2 epidemiological fitness, possibly through sfRNA-protein interactions. Collectively, our findings indicate that 3′ UTRs are important determinants of DENV fitness in human-mosquito cycles. Dengue viruses (DENVs) preserve RNA elements in their 3′ untranslated region (UTR). Quantification of natural selection revealed positive selection on DENV2 sfRNA Flaviviral nuclease-resistant RNAs (fNR) in the 3′ UTRs contribute to DENV speciation A highly evolving fNR structure appears to increase DENV2 epidemiological fitness
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Affiliation(s)
- Esteban Finol
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Swiss Tropical and Public Health Institute, University of Basel, Basel 4051, Switzerland; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore; Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117549, Singapore.
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112
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Oliveira LG, Peron JPS. Viral receptors for flaviviruses: Not only gatekeepers. J Leukoc Biol 2019; 106:695-701. [PMID: 31063609 DOI: 10.1002/jlb.mr1118-460r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/03/2019] [Accepted: 04/10/2019] [Indexed: 12/20/2022] Open
Abstract
Arboviruses have been a huge threat for human health since the discovery of yellow fever virus in 1901. Arboviruses are arthropod born viruses, mainly transmitted by mosquitoes and ticks, responsible for more than thousands of deaths annually. The Flavivirideae family is probably the most clinically relevant, as it is composed of very important agents, such as dengue, yellow fever, West Nile, Japanese encephalitis, and, recently, Zika virus. Intriguingly, despite their structural and genomic similarities, flaviviruses may cause conditions ranging from mild infections with fever, cutaneous rash, and headache, to very severe cases, such as hemorrhagic fever, encephalitis, Guillain-Barré syndrome, and microcephaly. These differences may greatly rely on viral burden, tissue tropism, and mechanisms of immune evasion that may depend on both viral and host genetic factors. Unfortunately, very little is known about the biology of these factors, and how they orchestrate these differences. In this context, viral structural proteins and host cellular receptors may have a great relevance, as their interaction dictates not only viral tissue tropism, but also a plethora on intracellular mechanisms that may greatly account for either failure or success of infection. A great number of viral receptors have been described so far, although there is still a huge gap in understanding their overall role during infection. Here we discuss some important aspects triggered after the interaction of flaviviruses and host membrane receptors, and how they change the overall outcome of the infection.
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Affiliation(s)
- Lilian G Oliveira
- Neuroimmune Interactions Laboratory, Institute of Biomedical Sciences, Department of Immunology, University of Sao Paulo, São Paulo, Brazil
| | - Jean Pierre Schatzmann Peron
- Immunopathology and Alergy PostGraduate Program, School of Medicine, University of São Paulo, Brazil.,Scientific Platform Pasteur, USP, São Paulo, Brazil
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113
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Schneider ADB, Wolfinger MT. Musashi binding elements in Zika and related Flavivirus 3'UTRs: A comparative study in silico. Sci Rep 2019; 9:6911. [PMID: 31061405 PMCID: PMC6502878 DOI: 10.1038/s41598-019-43390-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/23/2019] [Indexed: 12/16/2022] Open
Abstract
Zika virus (ZIKV) belongs to a class of neurotropic viruses that have the ability to cause congenital infection, which can result in microcephaly or fetal demise. Recently, the RNA-binding protein Musashi-1 (Msi1), which mediates the maintenance and self-renewal of stem cells and acts as a translational regulator, has been associated with promoting ZIKV replication, neurotropism, and pathology. Msi1 predominantly binds to single-stranded motifs in the 3' untranslated region (UTR) of RNA that contain a UAG trinucleotide in their core. We systematically analyzed the properties of Musashi binding elements (MBEs) in the 3'UTR of flaviviruses with a thermodynamic model for RNA folding. Our results indicate that MBEs in ZIKV 3'UTRs occur predominantly in unpaired, single-stranded structural context, thus corroborating experimental observations by a biophysical model of RNA structure formation. Statistical analysis and comparison with related viruses show that ZIKV MBEs are maximally accessible among mosquito-borne flaviviruses. Our study addresses the broader question of whether other emerging arboviruses can cause similar neurotropic effects through the same mechanism in the developing fetus by establishing a link between the biophysical properties of viral RNA and teratogenicity. Moreover, our thermodynamic model can explain recent experimental findings and predict the Msi1-related neurotropic potential of other viruses.
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Affiliation(s)
- Adriano de Bernardi Schneider
- Department of Medicine, University of California San Diego, 220 Dickinson St, Suite A, San Diego, CA, 92103, United States of America
| | - Michael T Wolfinger
- Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090, Vienna, Austria.
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114
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Cross ST, Michalski D, Miller MR, Wilusz J. RNA regulatory processes in RNA virus biology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1536. [PMID: 31034160 PMCID: PMC6697219 DOI: 10.1002/wrna.1536] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/13/2022]
Abstract
Numerous post‐transcriptional RNA processes play a major role in regulating the quantity, quality and diversity of gene expression in the cell. These include RNA processing events such as capping, splicing, polyadenylation and modification, but also aspects such as RNA localization, decay, translation, and non‐coding RNA‐associated regulation. The interface between the transcripts of RNA viruses and the various RNA regulatory processes in the cell, therefore, has high potential to significantly impact virus gene expression, regulation, cytopathology and pathogenesis. Furthermore, understanding RNA biology from the perspective of an RNA virus can shed considerable light on the broad impact of these post‐transcriptional processes in cell biology. Thus the goal of this article is to provide an overview of the richness of cellular RNA biology and how RNA viruses use, usurp and/or avoid the associated machinery to impact the outcome of infection. This article is categorized under:RNA in Disease and Development > RNA in Disease
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Affiliation(s)
- Shaun T Cross
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Daniel Michalski
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Megan R Miller
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
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115
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Zhang H, Keane SC. Advances that facilitate the study of large RNA structure and dynamics by nuclear magnetic resonance spectroscopy. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1541. [PMID: 31025514 PMCID: PMC7169810 DOI: 10.1002/wrna.1541] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/18/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022]
Abstract
The characterization of functional yet nonprotein coding (nc) RNAs has expanded the role of RNA in the cell from a passive player in the central dogma of molecular biology to an active regulator of gene expression. The misregulation of ncRNA function has been linked with a variety of diseases and disorders ranging from cancers to neurodegeneration. However, a detailed molecular understanding of how ncRNAs function has been limited; due, in part, to the difficulties associated with obtaining high-resolution structures of large RNAs. Tertiary structure determination of RNA as a whole is hampered by various technical challenges, all of which are exacerbated as the size of the RNA increases. Namely, RNAs tend to be highly flexible and dynamic molecules, which are difficult to crystallize. Biomolecular nuclear magnetic resonance (NMR) spectroscopy offers a viable alternative to determining the structure of large RNA molecules that do not readily crystallize, but is itself hindered by some technical limitations. Recently, a series of advancements have allowed the biomolecular NMR field to overcome, at least in part, some of these limitations. These advances include improvements in sample preparation strategies as well as methodological improvements. Together, these innovations pave the way for the study of ever larger RNA molecules that have important biological function. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Huaqun Zhang
- Biophysics Program, University of Michigan, Ann Arbor, Michigan
| | - Sarah C Keane
- Biophysics Program, University of Michigan, Ann Arbor, Michigan.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan
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116
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Structure mapping of dengue and Zika viruses reveals functional long-range interactions. Nat Commun 2019; 10:1408. [PMID: 30926818 PMCID: PMC6441010 DOI: 10.1038/s41467-019-09391-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 03/08/2019] [Indexed: 02/02/2023] Open
Abstract
Dengue (DENV) and Zika (ZIKV) viruses are clinically important members of the Flaviviridae family with an 11 kb positive strand RNA genome that folds to enable virus function. Here, we perform structure and interaction mapping on four DENV and ZIKV strains inside virions and in infected cells. Comparative analysis of SHAPE reactivities across serotypes nominates potentially functional regions that are highly structured, conserved, and contain low synonymous mutation rates. Interaction mapping by SPLASH identifies many pair-wise interactions, 40% of which form alternative structures, suggesting extensive structural heterogeneity. Analysis of shared interactions between serotypes reveals a conserved macro-organization whereby interactions can be preserved at physical locations beyond sequence identities. We further observe that longer-range interactions are preferentially disrupted inside cells, and show the importance of new interactions in virus fitness. These findings deepen our understanding of Flavivirus genome organization and serve as a resource for designing therapeutics in targeting RNA viruses.
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117
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Ochsenreiter R, Hofacker IL, Wolfinger MT. Functional RNA Structures in the 3'UTR of Tick-Borne, Insect-Specific and No-Known-Vector Flaviviruses. Viruses 2019; 11:E298. [PMID: 30909641 PMCID: PMC6466055 DOI: 10.3390/v11030298] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 12/21/2022] Open
Abstract
Untranslated regions (UTRs) of flaviviruses contain a large number of RNA structural elements involved in mediating the viral life cycle, including cyclisation, replication, and encapsidation. Here we report on a comparative genomics approach to characterize evolutionarily conserved RNAs in the 3 ' UTR of tick-borne, insect-specific and no-known-vector flaviviruses in silico. Our data support the wide distribution of previously experimentally characterized exoribonuclease resistant RNAs (xrRNAs) within tick-borne and no-known-vector flaviviruses and provide evidence for the existence of a cascade of duplicated RNA structures within insect-specific flaviviruses. On a broader scale, our findings indicate that viral 3 ' UTRs represent a flexible scaffold for evolution to come up with novel xrRNAs.
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Affiliation(s)
- Roman Ochsenreiter
- Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Vienna, Austria.
| | - Ivo L Hofacker
- Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Vienna, Austria.
- Research Group BCB, Faculty of Computer Science, University of Vienna, Währingerstraße 29, 1090 Vienna, Austria.
| | - Michael T Wolfinger
- Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Vienna, Austria.
- Research Group BCB, Faculty of Computer Science, University of Vienna, Währingerstraße 29, 1090 Vienna, Austria.
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118
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Fleming AM, Nguyen NLB, Burrows CJ. Colocalization of m 6A and G-Quadruplex-Forming Sequences in Viral RNA (HIV, Zika, Hepatitis B, and SV40) Suggests Topological Control of Adenosine N 6-Methylation. ACS CENTRAL SCIENCE 2019; 5:218-228. [PMID: 30834310 PMCID: PMC6396389 DOI: 10.1021/acscentsci.8b00963] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Indexed: 05/09/2023]
Abstract
This Outlook calls attention to two seemingly disparate and emerging fields regarding viral genomics that may be correlated in a way previously overlooked. First, we describe identification of conserved potential G-quadruplex-forming sequences (PQSs) in viral genomes relevant to human health. Studies have demonstrated that PQSs are highly conserved and can fold to G-quadruplexes (G4s) to regulate viral processes. Key examples include G4s as a countermeasure to the host's immune system or G4-guided regulation of replication or transcription. Second, emerging data are discussed concerning the epitranscriptomic modification N 6-methyladenosine (m6A) in viral RNA installed by host proteins in a consensus sequence favoring 5'-GG(m6A)C-3'. The proposed pathways by which m6A is written, read, and erased in viral RNA genomes and the impact this has on viral replication are described. The structural reason why certain sites are selected for modification while others are not is still mysterious. Finally, we discuss our new observations regarding these previous sequencing data that identify m6A installation within the loops of two-tetrad PQSs in the RNA genomes of the Zika, HIV, hepatitis B, and SV40 viruses. We hypothesize that conserved viral PQSs can provide a framework (sequence and/or structural) for m6A installation. We also discuss literature sources suggesting that PQSs as sites of RNA modification could be a general phenomenon. We anticipate our observations will provide ample opportunities for exciting discoveries regarding the interplay between G4 structures and epitranscriptomic modifications of RNA.
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Affiliation(s)
- Aaron M. Fleming
- Department of Chemistry, University
of Utah, Salt Lake
City, Utah 84112-0850, United States
| | - Ngoc L. B. Nguyen
- Department of Chemistry, University
of Utah, Salt Lake
City, Utah 84112-0850, United States
| | - Cynthia J. Burrows
- Department of Chemistry, University
of Utah, Salt Lake
City, Utah 84112-0850, United States
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119
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An H, Cai Z, Yang Y, Wang Z, Liu DX, Fang S. Identification and formation mechanism of a novel noncoding RNA produced by avian infectious bronchitis virus. Virology 2019; 528:176-180. [PMID: 30616206 PMCID: PMC7112027 DOI: 10.1016/j.virol.2018.12.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/19/2018] [Accepted: 12/26/2018] [Indexed: 12/12/2022]
Abstract
Viral noncoding (nc) RNAs have been shown to play important roles in viral life cycle. Many viruses employ different mechanism to produce ncRNAs. Here, we report that coronavirus infectious bronchitis virus (IBV) produces a novel ncRNA in virus-infected cells. This ncRNA consists of 563 nucleotides excluding a poly(A) tail, is mainly derived from the 3'-untranslated region of IBV genome, and contains a 63-nt-long of terminal leader sequence derived from the 5' end of the viral genome. Using mutagenesis and reverse genetics, we reveal that this ncRNA is a subgenomic RNA generated by discontinuous transcription mechanism.
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Affiliation(s)
- Hongliu An
- College of Agriculture, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China
| | - Zhichao Cai
- College of Agriculture, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China
| | - Yuying Yang
- College of Animal Sciences, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China
| | - Zhaoxiong Wang
- College of Animal Sciences, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China
| | - Ding Xiang Liu
- South China Agricultural University, Guangdong Province Key Laboratory Microbial Signals & Disease Co, and Integrative Microbiology Research Centre, Guangzhou 510642, Guangdong, PR China.
| | - Shouguo Fang
- College of Agriculture, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China; College of Animal Sciences, Yangtze University, 88 Jingmilu, Jingzhou 434025, Hubei, PR China.
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120
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Human T cell leukemia virus type 1 and Zika virus: tale of two reemerging viruses with neuropathological sequelae of public health concern. J Neurovirol 2019; 25:289-300. [PMID: 30693421 DOI: 10.1007/s13365-019-00720-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/16/2018] [Accepted: 01/03/2019] [Indexed: 01/17/2023]
Abstract
Human T cell leukemia virus type 1 (HTLV-1) and Zika virus (ZIKV) have been considered neglected viruses of low public health concern until recently when incidences of HTLV-1 and ZIKV were observed to be linked to serious immune-related disease and neurological complications. This review will discuss the epidemiology, genomic evolution, virus-host interactions, virulence factors, neuropathological sequelae, and current perspectives of these reemerging viruses. There are no FDA-approved therapeutics or vaccines against these viruses, and as such, it is important for clinical trials to focus on developing vaccines that can induce cell-mediated immune response to confer long-term protective immunity. Furthermore, attention should be paid to reducing the transmission of these viruses through unprotected sex, infected blood during sharing of contaminated needles, donated blood and organs, and vertical transmission from mother to baby via breastfeeding. There is an urgent need to re-evaluate repurposing current antiviral therapies as well as developing novel antiviral agents with enhanced efficacy due to the high morbidity rate associated with these two reemerging chronic viral diseases.
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121
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Gutierrez B, Escalera-Zamudio M, Pybus OG. Parallel molecular evolution and adaptation in viruses. Curr Opin Virol 2019; 34:90-96. [PMID: 30703578 PMCID: PMC7102768 DOI: 10.1016/j.coviro.2018.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/11/2018] [Indexed: 01/05/2023]
Abstract
Parallel molecular evolution is the independent evolution of the same genotype or phenotype from distinct ancestors. The simple genomes and rapid evolution of many viruses mean they are useful model systems for studying parallel evolution by natural selection. Parallel adaptation occurs in the context of several viral behaviours, including cross-species transmission, drug resistance, and host immune escape, and its existence suggests that at least some aspects of virus evolution and emergence are repeatable and predictable. We introduce examples of virus parallel evolution and summarise key concepts. We outline the difficulties in detecting parallel adaptation using virus genomes, with a particular focus on phylogenetic and structural approaches, and we discuss future approaches that may improve our understanding of the phenomenon.
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Affiliation(s)
| | | | - Oliver G Pybus
- Department of Zoology, University of Oxford, Oxford, United Kingdom.
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122
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Damas ND, Fossat N, Scheel TKH. Functional Interplay between RNA Viruses and Non-Coding RNA in Mammals. Noncoding RNA 2019; 5:ncrna5010007. [PMID: 30646609 PMCID: PMC6468702 DOI: 10.3390/ncrna5010007] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/31/2018] [Accepted: 01/08/2019] [Indexed: 12/12/2022] Open
Abstract
Exploring virus–host interactions is key to understand mechanisms regulating the viral replicative cycle and any pathological outcomes associated with infection. Whereas interactions at the protein level are well explored, RNA interactions are less so. Novel sequencing methodologies have helped uncover the importance of RNA–protein and RNA–RNA interactions during infection. In addition to messenger RNAs (mRNAs), mammalian cells express a great number of regulatory non-coding RNAs, some of which are crucial for regulation of the immune system whereas others are utilized by viruses. It is thus becoming increasingly clear that RNA interactions play important roles for both sides in the arms race between virus and host. With the emerging field of RNA therapeutics, such interactions are promising antiviral targets. In this review, we discuss direct and indirect RNA interactions occurring between RNA viruses or retroviruses and host non-coding transcripts upon infection. In addition, we review RNA virus derived non-coding RNAs affecting immunological and metabolic pathways of the host cell typically to provide an advantage to the virus. The relatively few known examples of virus–host RNA interactions suggest that many more await discovery.
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Affiliation(s)
- Nkerorema Djodji Damas
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
| | - Nicolas Fossat
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
| | - Troels K H Scheel
- Copenhagen Hepatitis C Program (CO-HEP), Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
- Department of Infectious Diseases, Hvidovre Hospital, DK-2650 Hvidovre, Denmark.
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY 10065, USA.
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123
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Svyatchenko VA, Razumov IA, Protopopova EV, Demina AV, Solovieva OI, Zavjalov EL, Loktev VB. Zika virus has an oncolytic activity against human glioblastoma U87 cells. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj18.448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Glioblastoma is a highly lethal brain cancer. Virotherapy with the use of oncolytic viruses has since recently been regarded as a promising approach for the clinic treatment of human glioblastomas. The purpose of this work was to perform a primary evaluation of the Zika virus as a potential oncolytic agent against glioblastomas.In vitroexperiments showed that the Zika virus strain MR 766 is able to selectively infect and lyse neoplastic cells of the human glioblastoma cell line U87 MG. The selectivity index (SI, the ratio of infectious titer for tumor cells to titer on normal untransformed cells) was 2·102. The selectivity of the replicative activity of Zika virus in relation to U87 MG glioblastoma cells was additionally confrmed by indirect immunofluorescence. Using the model of immunodefcient SCID mice with subcutaneous xenografts of human glioblastoma U87 MG, a strong antitumor activity of the Zika virus under a course (daily for 4 days) of intratumoral administration of 5·105 TCID50 of Zika virus was shown. Treatment with Zika virus resulted in more than a 10fold reduction in mean volumes of tumors. The tumor growth inhibition index was 92.63 %. Recurrences (metastases) of tumor regrowth were not registered within 64 days of observation. This result demonstrated the prospect of further indepth studies of the Zika virus as a potential oncolytic agent against human glioblastomas.
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Affiliation(s)
| | - I. A. Razumov
- State Research Center of Virology and Biotechnology “Vector”; Institute of Cytology and Genetics, SB RAS
| | | | - A. V. Demina
- State Research Center of Virology and Biotechnology “Vector”
| | | | | | - V. B. Loktev
- State Research Center of Virology and Biotechnology “Vector”; Institute of Cytology and Genetics, SB RAS
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124
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Castro FL, Geddes VEV, Monteiro FLL, Gonçalves RMDT, Campanati L, Pezzuto P, Paquin-Proulx D, Schamber-Reis BL, Azevedo GS, Gonçalves AL, Cunha DP, Moreira MEL, Vasconcelos ZFM, Chimeli L, Melo A, Tanuri A, Nixon DF, Ribeiro-Alves M, Aguiar RS. MicroRNAs 145 and 148a Are Upregulated During Congenital Zika Virus Infection. ASN Neuro 2019; 11:1759091419850983. [PMID: 31213064 PMCID: PMC6585135 DOI: 10.1177/1759091419850983] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/04/2019] [Accepted: 04/13/2019] [Indexed: 12/24/2022] Open
Abstract
Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) member of the Flaviviridae family, which has been associated with the development of the congenital Zika syndrome (CZS). RNA viruses, such as flaviviruses, have been reported to exert a profound impact on host microRNAs (miRNAs). Cellular miRNAs modulated by ZIKV may help identify cellular pathways of relevance to pathogenesis. Here, we screened 754 human cellular miRNAs modulated by ZIKV infection (Brazilian PE strain) in a neuroblastoma cell line. Seven miRNAs (miR-99a*, miR-126*, miR-190b, miR-361-3p, miR-522-3p, miR-299-5p, and miR-1267) were downregulated during ZIKV infection, while miR-145 was upregulated. Furthermore, 11 miRNAs were exclusively expressed in ZIKV-infected (miR-148a, miR-342-5p, miR-598, and miR-708-3p) or mock cells (miR-208, miR-329, miR-432-5p, miR-488, miR-518b, miR-520g, and miR-767-5p). Furthermore, in silico analysis indicated that some central nervous system, cellular migration, and adhesion function-related biological processes were overrepresented in the list of target genes of the miRNAs regulated in ZIKV-infected cells, especially for miR-145 and miR-148a. The induction of miR-145 and miR-148a was confirmed in postmortem brain samples from stillborn with severe CZS. Finally, we determined the expression regulation of microcephaly related genes through RNA interference pathway caused by ZIKV directly on neuron cells.
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Affiliation(s)
- Fernanda L. Castro
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victor E. V. Geddes
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fábio L. L. Monteiro
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raphael M. D. T. Gonçalves
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Loraine Campanati
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paula Pezzuto
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dominic Paquin-Proulx
- Department of Microbiology, Immunology & Tropical Medicine, The George Washington University, Washington, DC, USA
| | - Bruno L. Schamber-Reis
- Faculdade de Ciências Médicas de Campina Grande, Núcleo de Genética Médica, Centro Universitário UniFacisa, Campina Grande, Brazil
| | | | | | | | | | | | - Leila Chimeli
- Laboratório de Neuropatologia, Instituto Estadual do Cérebro, Rio de Janeiro, Brazil
| | - Adriana Melo
- Faculdade de Ciências Médicas de Campina Grande, Núcleo de Genética Médica, Centro Universitário UniFacisa, Campina Grande, Brazil
- Instituto de Pesquisa Professor Amorim Neto, Campina Grande, Brazil
| | - Amilcar Tanuri
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Douglas F. Nixon
- Division of Infectious Diseases, Weill Cornell Medicine, New York City, NY, USA
| | | | - Renato S. Aguiar
- Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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125
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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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126
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Abstract
During infection, viruses often produce subgenomic RNAs (sgRNAs) that either serve as the template for protein synthesis or act as “riboregulators” that interact with and influence the viral and cellular machinery. Recently, a mechanism for producing sgRNAs was found that depends on the presence of specifically structured RNA elements (xrRNAs). However, the degree to which this mechanism is used, where the elements are found, their structural diversity, and what types of sgRNAs are produced by this pathway were unclear. This article describes the discovery of these structured RNA elements in two large families of plant viruses and shows that they are used to produce both protein-coding sgRNAs and “riboregulatory” RNAs. These discoveries provide evidence that xrRNA-based RNA maturation pathways may be more widespread than previously anticipated and that they are involved in producing a variety of RNAs of diverse functions. Many viruses produce protein-coding and noncoding subgenomic RNAs (sgRNAs) that are critical for infection. A recently discovered pathway for viral sgRNA production uses exoribonuclease-resistant RNAs (xrRNAs), discrete folded RNA elements that block the processive exoribonucleolytic degradation of RNA. xrRNAs are widespread in animal-infecting flaviviruses but had been found only in three members of the plant virus genus Dianthovirus. Also, xrRNAs had been found only in the 3′ untranslated regions (3′UTRs) of viral RNAs, where they produce noncoding sgRNAs. The degree to which xrRNA elements exist in other viruses, the conservation of their ring-like fold, and the ability of xrRNAs to operate in diverse contexts were unknown. Using computational tools and biochemical assays, we discovered xrRNA elements pervading two large families of plant-infecting RNA viruses, demonstrating their importance and widespread utility. Comparison of the sequences and functional requirements suggests that all adopt the characteristic ring-like fold. Unexpectedly, many of these newly discovered xrRNAs are located in intergenic regions rather than 3´UTRs, and some are associated with the 5′ ends of subgenomic RNAs that encode viral proteins. This suggests that xrRNAs are involved in the production of both coding and noncoding subgenomic RNAs and can operate as part of broader mechanisms to regulate RNA levels and protein expression. These discoveries expand the potential roles for xrRNAs and suggest that xrRNAs may represent a more general strategy for RNA maturation and maintenance than previously known.
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127
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Andrews RJ, Roche J, Moss WN. ScanFold: an approach for genome-wide discovery of local RNA structural elements-applications to Zika virus and HIV. PeerJ 2018; 6:e6136. [PMID: 30627482 PMCID: PMC6317755 DOI: 10.7717/peerj.6136] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/15/2018] [Indexed: 12/24/2022] Open
Abstract
In addition to encoding RNA primary structures, genomes also encode RNA secondary and tertiary structures that play roles in gene regulation and, in the case of RNA viruses, genome replication. Methods for the identification of functional RNA structures in genomes typically rely on scanning analysis windows, where multiple partially-overlapping windows are used to predict RNA structures and folding metrics to deduce regions likely to form functional structure. Separate structural models are produced for each window, where the step size can greatly affect the returned model. This makes deducing unique local structures challenging, as the same nucleotides in each window can be alternatively base paired. We are presenting here a new approach where all base pairs from analysis windows are considered and weighted by favorable folding. This results in unique base pairing throughout the genome and the generation of local regions/structures that can be ranked by their propensity to form unusually thermodynamically stable folds. We applied this approach to the Zika virus (ZIKV) and HIV-1 genomes. ZIKV is linked to a variety of neurological ailments including microcephaly and Guillain-Barré syndrome and its (+)-sense RNA genome encodes two, previously described, functionally essential structured RNA regions. HIV, the cause of AIDS, contains multiple functional RNA motifs in its genome, which have been extensively studied. Our approach is able to successfully identify and model the structures of known functional motifs in both viruses, while also finding additional regions likely to form functional structures. All data have been archived at the RNAStructuromeDB (www.structurome.bb.iastate.edu), a repository of RNA folding data for humans and their pathogens.
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Affiliation(s)
- Ryan J. Andrews
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Julien Roche
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Walter N. Moss
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, USA
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128
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Han Y, Mesplède T. Investigational drugs for the treatment of Zika virus infection: a preclinical and clinical update. Expert Opin Investig Drugs 2018; 27:951-962. [PMID: 30430882 DOI: 10.1080/13543784.2018.1548609] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION The Zika virus (ZIKV) infection results in severe neurological complications and has emerged as a threat to public health worldwide. No drugs or vaccines are available for use in the clinic and the need for novel and effective therapeutic agents is urgent. AREAS COVERED This review describes the latest progress of antiviral development for the treatment of ZIKV infection; it primarily focuses on the literature describing 20 potential anti-ZIKV drugs/agents currently being tested in vivo or in clinical trials. The paper also discusses the need for novel ZIKV inhibitors and the critical issues for successful antiviral drug development. EXPERT OPINION So far, 20 compounds have been tested in vivo and three in the clinical trials; progressing these compounds to the clinic is a challenge. Novel ZIKV inhibitors that target virus or host factors are urgently needed. Knowledge-driven drug repurposing, structure-based discovery, RNA interference, long noncoding RNAs, miRNAs, and peptide inhibitors may pave the way for the discovery of such novel agents.
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Affiliation(s)
- Yingshan Han
- a McGill University AIDS Centre , Lady Davis Institute for Medical Research, Jewish General Hospital , Montreal , Canada
| | - Thibault Mesplède
- a McGill University AIDS Centre , Lady Davis Institute for Medical Research, Jewish General Hospital , Montreal , Canada
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129
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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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130
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Soto-Acosta R, Xie X, Shan C, Baker CK, Shi PY, Rossi SL, Garcia-Blanco MA, Bradrick S. Fragile X mental retardation protein is a Zika virus restriction factor that is antagonized by subgenomic flaviviral RNA. eLife 2018; 7:39023. [PMID: 30511641 PMCID: PMC6279352 DOI: 10.7554/elife.39023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/12/2018] [Indexed: 12/19/2022] Open
Abstract
Subgenomic flaviviral RNA (sfRNA) accumulates during infection due to incomplete degradation of viral genomes and interacts with cellular proteins to promote infection. Here we identify host proteins that bind the Zika virus (ZIKV) sfRNA. We identified fragile X mental retardation protein (FMRP) as a ZIKV sfRNA-binding protein and confirmed this interaction in cultured cells and mouse testes. Depletion of FMRP elevated viral translation and enhanced ZIKV infection, indicating that FMRP is a ZIKV restriction factor. We further observed that an attenuated ZIKV strain compromised for sfRNA production was disproportionately stimulated by FMRP knockdown, suggesting that ZIKV sfRNA antagonizes FMRP activity. Importantly, ZIKV infection and expression of ZIKV sfRNA upregulated endogenous FMRP target genes in cell culture and ZIKV-infected mice. Together, our observations identify FMRP as a ZIKV restriction factor whose activity is antagonized by the sfRNA. Interaction between ZIKV and FMRP has significant implications for the pathogenesis of ZIKV infections.
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Affiliation(s)
- Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Xuping Xie
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Chao Shan
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Coleman K Baker
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, United States.,Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States
| | - Shannan L Rossi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Department of Pathology, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Shelton Bradrick
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
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131
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Russo J, Mundell CT, Charley PA, Wilusz C, Wilusz J. Engineered viral RNA decay intermediates to assess XRN1-mediated decay. Methods 2018; 155:116-123. [PMID: 30521847 DOI: 10.1016/j.ymeth.2018.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/27/2018] [Accepted: 11/30/2018] [Indexed: 01/23/2023] Open
Abstract
Both RNA synthesis and decay must be balanced within a cell to achieve proper gene expression. Additionally, modulation of RNA decay specifically offers the cell an opportunity to rapidly reshape the transcriptome in response to specific stimuli or cues. Therefore, it is critical to understand the underlying mechanisms through which RNA decay contribute to gene expression homeostasis. Cell-free reconstitution approaches have been used successfully to reveal mechanisms associated with numerous post-transcriptional RNA processes. Historically, it has been difficult to examine all aspects of RNA decay in such an in vitro setting due, in part, to limitations on the ability to resolve larger RNAs through denaturing polyacrylamide gels. Thus, in vitro systems to study RNA decay rely on smaller, less biologically relevant RNA fragments. Herein, we present an approach to more confidently examine RNA decay parameters of large mRNA size transcripts through the inclusion of an engineered XRN1-resistant reporter RNA (xrRNA). By placing a 67 nucleotide xrRNA near the 3' end of any in vitro transcribed RNA with variable size or sequence context, investigators can observe the accumulation of the xrRNA as a readout of exoribonuclease-mediated 5'-3' decay. This approach may allow in vitro RNA decay assays to include full biologically relevant mRNA/mRNPs, extending their utility and allow improved experimental design considerations to promote biologically relevant outcomes.
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Affiliation(s)
- Joseph Russo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80525, United States
| | - Cary T Mundell
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80525, United States; Program in Cell & Molecular Biology, Colorado State University, Fort Collins, CO 80525, United States
| | - Phillida A Charley
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80525, United States
| | - Carol Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80525, United States; Program in Cell & Molecular Biology, Colorado State University, Fort Collins, CO 80525, United States
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80525, United States; Program in Cell & Molecular Biology, Colorado State University, Fort Collins, CO 80525, United States.
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132
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Pena LJ, Miranda Guarines K, Duarte Silva AJ, Sales Leal LR, Mendes Félix D, Silva A, de Oliveira SA, Junqueira Ayres CF, Júnior AS, de Freitas AC. In vitro and in vivo models for studying Zika virus biology. J Gen Virol 2018; 99:1529-1550. [DOI: 10.1099/jgv.0.001153] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Lindomar José Pena
- 1Department of Virology, Aggeu Magalhaes Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Klarissa Miranda Guarines
- 1Department of Virology, Aggeu Magalhaes Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Anna Jéssica Duarte Silva
- 2Department of Genetics, Laboratory of Molecular Studies and Experimental Therapy (LEMTE), Center of Biological Sciences, Federal University of Pernambuco (UFPE), Recife, Pernambuco, Brazil
| | - Lígia Rosa Sales Leal
- 2Department of Genetics, Laboratory of Molecular Studies and Experimental Therapy (LEMTE), Center of Biological Sciences, Federal University of Pernambuco (UFPE), Recife, Pernambuco, Brazil
| | - Daniele Mendes Félix
- 1Department of Virology, Aggeu Magalhaes Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Adalúcia Silva
- 1Department of Virology, Aggeu Magalhaes Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | - Sheilla Andrade de Oliveira
- 3Department of Immunology, Aggeu Magalhaes Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Recife, Pernambuco, Brazil
| | | | - Abelardo Silva Júnior
- 5Department of Veterinary Medicine, Federal University of Viçosa (UFV), Viçosa, Minas Gerais, Brazil
| | - Antonio Carlos de Freitas
- 2Department of Genetics, Laboratory of Molecular Studies and Experimental Therapy (LEMTE), Center of Biological Sciences, Federal University of Pernambuco (UFPE), Recife, Pernambuco, Brazil
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133
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Li P, Wei Y, Mei M, Tang L, Sun L, Huang W, Zhou J, Zou C, Zhang S, Qin CF, Jiang T, Dai J, Tan X, Zhang QC. Integrative Analysis of Zika Virus Genome RNA Structure Reveals Critical Determinants of Viral Infectivity. Cell Host Microbe 2018; 24:875-886.e5. [PMID: 30472207 DOI: 10.1016/j.chom.2018.10.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/21/2018] [Accepted: 10/24/2018] [Indexed: 01/25/2023]
Abstract
Zika virus (ZIKV) strains can be classified into the ancestral African and contemporary Asian lineages, with the latter responsible for recent epidemics associated with neurological conditions. To understand how Asian strains lead to exacerbated disease, a crucial step is identifying genomic variations that affect infectivity and pathogenicity. Here we use two high-throughput sequencing approaches to assess RNA secondary structures and intramolecular RNA-RNA interactions in vivo for the RNA genomes of Asian and African ZIKV lineages. Our analysis identified functional RNA structural elements and a functional long-range intramolecular interaction specific for the Asian epidemic strains. Mutants that disrupt this extended RNA interaction between the 5' UTR and the E protein coding region reduce virus infectivity, which is partially rescued with compensatory mutants, restoring this RNA-RNA interaction. These findings illuminate the structural basis of ZIKV regulation and provide a resource for the discovery of RNA structural elements important for ZIKV infection.
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Affiliation(s)
- Pan Li
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yifan Wei
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Miao Mei
- School of Pharmaceutical Sciences, Center for Infectious Disease Research, School of Medicine, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Lei Tang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lei Sun
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wenze Huang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianyu Zhou
- Bioinformatics Division, BNRIST, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China
| | - Chunlin Zou
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Shaojun Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tao Jiang
- Bioinformatics Division, BNRIST, Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China; Department of Computer Science and Engineering, University of California, Riverside, CA 92521, USA
| | - Jianfeng Dai
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Xu Tan
- School of Pharmaceutical Sciences, Center for Infectious Disease Research, School of Medicine, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
| | - Qiangfeng Cliff Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology, Center for Synthetic and Systems Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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134
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Ziv O, Gabryelska MM, Lun ATL, Gebert LFR, Sheu-Gruttadauria J, Meredith LW, Liu ZY, Kwok CK, Qin CF, MacRae IJ, Goodfellow I, Marioni JC, Kudla G, Miska EA. COMRADES determines in vivo RNA structures and interactions. Nat Methods 2018; 15:785-788. [PMID: 30202058 PMCID: PMC6168409 DOI: 10.1038/s41592-018-0121-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/20/2018] [Indexed: 01/07/2023]
Abstract
The structural flexibility of RNA underlies fundamental biological processes, but there are no methods for exploring the multiple conformations adopted by RNAs in vivo. We developed cross-linking of matched RNAs and deep sequencing (COMRADES) for in-depth RNA conformation capture, and a pipeline for the retrieval of RNA structural ensembles. Using COMRADES, we determined the architecture of the Zika virus RNA genome inside cells, and identified multiple site-specific interactions with human noncoding RNAs.
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Affiliation(s)
- Omer Ziv
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
| | - Marta M Gabryelska
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Aaron T L Lun
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Luca F R Gebert
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Jessica Sheu-Gruttadauria
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Luke W Meredith
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Zhong-Yu Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Medicine (Shenzhen), Sun Yat-sen University, Guangzhou, China
| | - Chun Kit Kwok
- Department of Chemistry, City University of Hong Kong, Hong Kong, China
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Ian J MacRae
- Department of Integrative Structural and Computational Biology, the Scripps Research Institute, La Jolla, CA, USA
| | - Ian Goodfellow
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
- Wellcome Sanger Institute, Cambridge, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, UK.
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK.
- Department of Genetics, University of Cambridge, Cambridge, UK.
- Wellcome Sanger Institute, Cambridge, UK.
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135
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Slonchak A, Khromykh AA. Subgenomic flaviviral RNAs: What do we know after the first decade of research. Antiviral Res 2018; 159:13-25. [PMID: 30217649 DOI: 10.1016/j.antiviral.2018.09.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022]
Abstract
The common feature of flaviviral infection is the accumulation of abundant virus-derived noncoding RNA, named flaviviral subgenomic RNA (sfRNA) in infected cells. This RNA represents a product of incomplete degradation of viral genomic RNA by the cellular 5'-3' exoribonuclease XRN1 that stalls at the conserved highly structured elements in the 3' untranslated region (UTR). This mechanism of sfRNA generation was discovered a decade ago and since then sfRNA has been a focus of intense research. The ability of flaviviruses to produce sfRNA was shown to be evolutionary conserved in all members of Flavivirus genus. Mutations in the 3'UTR that affect production of sfRNAs and their interactions with host factors showed that sfRNAs are responsible for viral pathogenicity, host adaptation, and emergence of new pathogenic strains. RNA structural elements required for XRN1 stalling have been elucidated and the role of sfRNAs in inhibiting host antiviral responses in arthropod and vertebrate hosts has been demonstrated. Some molecular mechanisms determining these properties of sfRNA have been recently characterized, while other aspects of sfRNA functions remain an open avenue for future research. In this review we summarise the current state of knowledge on the mechanisms of generation and functional roles of sfRNAs in the life cycle of flaviviruses and highlight the gaps in our knowledge to be addressed in the future.
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Affiliation(s)
- Andrii Slonchak
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Alexander A Khromykh
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
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136
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Early Events in Japanese Encephalitis Virus Infection: Viral Entry. Pathogens 2018; 7:pathogens7030068. [PMID: 30104482 PMCID: PMC6161159 DOI: 10.3390/pathogens7030068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne zoonotic flavivirus, is an enveloped positive-strand RNA virus that can cause a spectrum of clinical manifestations, ranging from mild febrile illness to severe neuroinvasive disease. Today, several killed and live vaccines are available in different parts of the globe for use in humans to prevent JEV-induced diseases, yet no antivirals are available to treat JEV-associated diseases. Despite the progress made in vaccine research and development, JEV is still a major public health problem in southern, eastern, and southeastern Asia, as well as northern Oceania, with the potential to become an emerging global pathogen. In viral replication, the entry of JEV into the cell is the first step in a cascade of complex interactions between the virus and target cells that is required for the initiation, dissemination, and maintenance of infection. Because this step determines cell/tissue tropism and pathogenesis, it is a promising target for antiviral therapy. JEV entry is mediated by the viral glycoprotein E, which binds virions to the cell surface (attachment), delivers them to endosomes (endocytosis), and catalyzes the fusion between the viral and endosomal membranes (membrane fusion), followed by the release of the viral genome into the cytoplasm (uncoating). In this multistep process, a collection of host factors are involved. In this review, we summarize the current knowledge on the viral and cellular components involved in JEV entry into host cells, with an emphasis on the initial virus-host cell interactions on the cell surface.
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137
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Chen YS, Fan YH, Tien CF, Yueh A, Chang RY. The conserved stem-loop II structure at the 3' untranslated region of Japanese encephalitis virus genome is required for the formation of subgenomic flaviviral RNA. PLoS One 2018; 13:e0201250. [PMID: 30048535 PMCID: PMC6062100 DOI: 10.1371/journal.pone.0201250] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 07/11/2018] [Indexed: 01/02/2023] Open
Abstract
Flaviviruses accumulate abundant subgenomic RNA (sfRNA) in infected cells. It has been reported that sfRNA results from stalling of host 5’-to-3’ exoribonuclease XRN1 at the highly structured RNA of the 3’ untranslated region (UTR). Although XRN1 digestion of a 3’-terminal 800-nt RNA could stall at a position to generate the sfRNA in vitro, we found that knocking out XRN1 had no effect on the accumulation of sfRNA in Japanese encephalitis virus (JEV) infected cells. Mutagenesis studies revealed that the stemloop II (SLII) at the 3’ UTR is required for the accumulation of sfRNA. According to the results of an in vitro RNA-dependent RNA polymerase (RdRp) assay, the (-)10431-10566 RNA fragment, containing the putative promoter on the antigenome for the sfRNA transcription, binds to RdRp protein and exhibits a strong promoter activity. Taken together, our results indicate that the JEV sfRNA could be transcribed initially and then be trimmed by XRN1 or other unidentified exoribonucleases.
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Affiliation(s)
- Yi-Shiuan Chen
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Yi-Hsin Fan
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Chih-Feng Tien
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Andrew Yueh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, Taiwan, ROC
| | - Ruey-Yi Chang
- Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
- * E-mail:
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138
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Beaver JT, Lelutiu N, Habib R, Skountzou I. Evolution of Two Major Zika Virus Lineages: Implications for Pathology, Immune Response, and Vaccine Development. Front Immunol 2018; 9:1640. [PMID: 30072993 PMCID: PMC6058022 DOI: 10.3389/fimmu.2018.01640] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/03/2018] [Indexed: 12/13/2022] Open
Abstract
Zika virus (ZIKV) became a public health emergency of global concern in 2015 due to its rapid expansion from French Polynesia to Brazil, spreading quickly throughout the Americas. Its unexpected correlation to neurological impairments and defects, now known as congenital Zika syndrome, brought on an urgency to characterize the pathology and develop safe, effective vaccines. ZIKV genetic analyses have identified two major lineages, Asian and African, which have undergone substantial changes during the past 50 years. Although ZIKV infections have been circulating throughout Africa and Asia for the later part of the 20th century, the symptoms were mild and not associated with serious pathology until now. ZIKV evolution also took the form of novel modes of transmission, including maternal-fetal transmission, sexual transmission, and transmission through the eye. The African and Asian lineages have demonstrated differential pathogenesis and molecular responses in vitro and in vivo. The limited number of human infections prior to the 21st century restricted ZIKV research to in vitro studies, but current animal studies utilize mice deficient in type I interferon (IFN) signaling in order to invoke enhanced viral pathogenesis. This review examines ZIKV strain differences from an evolutionary perspective, discussing how these differentially impact pathogenesis via host immune responses that modulate IFN signaling, and how these differential effects dictate the future of ZIKV vaccine candidates.
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Affiliation(s)
| | | | | | - Ioanna Skountzou
- Department of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States
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139
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A folded viral noncoding RNA blocks host cell exoribonucleases through a conformationally dynamic RNA structure. Proc Natl Acad Sci U S A 2018; 115:6404-6409. [PMID: 29866852 DOI: 10.1073/pnas.1802429115] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Folded RNA elements that block processive 5' → 3' cellular exoribonucleases (xrRNAs) to produce biologically active viral noncoding RNAs have been discovered in flaviviruses, potentially revealing a new mode of RNA maturation. However, whether this RNA structure-dependent mechanism exists elsewhere and, if so, whether a singular RNA fold is required, have been unclear. Here we demonstrate the existence of authentic RNA structure-dependent xrRNAs in dianthoviruses, plant-infecting viruses unrelated to animal-infecting flaviviruses. These xrRNAs have no sequence similarity to known xrRNAs; thus, we used a combination of biochemistry and virology to characterize their sequence requirements and mechanism of stopping exoribonucleases. By solving the structure of a dianthovirus xrRNA by X-ray crystallography, we reveal a complex fold that is very different from that of the flavivirus xrRNAs. However, both versions of xrRNAs contain a unique topological feature, a pseudoknot that creates a protective ring around the 5' end of the RNA structure; this may be a defining structural feature of xrRNAs. Single-molecule FRET experiments reveal that the dianthovirus xrRNAs undergo conformational changes and can use "codegradational remodeling," exploiting the exoribonucleases' degradation-linked helicase activity to help form their resistant structure; such a mechanism has not previously been reported. Convergent evolution has created RNA structure-dependent exoribonuclease resistance in different contexts, which establishes it as a general RNA maturation mechanism and defines xrRNAs as an authentic functional class of RNAs.
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140
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Tham HW, Balasubramaniam V, Ooi MK, Chew MF. Viral Determinants and Vector Competence of Zika Virus Transmission. Front Microbiol 2018; 9:1040. [PMID: 29875751 PMCID: PMC5974093 DOI: 10.3389/fmicb.2018.01040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/02/2018] [Indexed: 12/16/2022] Open
Abstract
Zika virus (ZIKV) has emerged as a new global health threat. Since its first discovery in Zika forest in Uganda, this virus has been isolated from several mosquito species, including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America. This has gained attention of the scientific community to elucidate the epidemiology and transmission of ZIKV. Despite its strong attention on clinical aspects for healthcare professionals, the relationships between ZIKV and its principal vectors, A. aegypti and A. albopictus, have not gained substantial interest in the scientific research community. As such, this review aims to summarize the current knowledge on ZIKV tropism and some important mechanisms which may be employed by the virus for effective strategies on viral survival in mosquitoes. In addition, this review identifies the areas of research that should be placed attention to, for which to be exploited for novel mosquito control strategies.
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Affiliation(s)
- Hong-Wai Tham
- Biology Research Laboratory, Faculty of Pharmacy, SEGi University, Petaling Jaya, Malaysia
| | - Vinod Balasubramaniam
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Subang Jaya, Malaysia
| | - Man K. Ooi
- Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Subang Jaya, Malaysia
| | - Miaw-Fang Chew
- Centre for Virus and Vaccine Research, School of Science and Technology, Sunway University, Subang Jaya, Malaysia
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141
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Simões ML, Caragata EP, Dimopoulos G. Diverse Host and Restriction Factors Regulate Mosquito-Pathogen Interactions. Trends Parasitol 2018; 34:603-616. [PMID: 29793806 DOI: 10.1016/j.pt.2018.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/25/2018] [Accepted: 04/26/2018] [Indexed: 12/12/2022]
Abstract
Mosquitoes transmit diseases that seriously impact global human health. Despite extensive knowledge of the life cycles of mosquito-borne parasites and viruses within their hosts, control strategies have proven insufficient to halt their spread. An understanding of the relationships established between such pathogens and the host tissues they inhabit is therefore paramount for the development of new strategies that specifically target these interactions, to prevent the pathogens' maturation and transmission. Here we present an updated account of the antagonists and host factors that affect the development of Plasmodium, the parasite causing malaria, and mosquito-borne viruses, such as dengue virus and Zika virus, within their mosquito vectors, and we discuss the similarities and differences between Plasmodium and viral systems, looking toward the elucidation of new targets for disease control.
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Affiliation(s)
- Maria L Simões
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; These authors contributed equally
| | - Eric P Caragata
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; These authors contributed equally
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
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142
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Watkins AM, Geniesse C, Kladwang W, Zakrevsky P, Jaeger L, Das R. Blind prediction of noncanonical RNA structure at atomic accuracy. SCIENCE ADVANCES 2018; 4:eaar5316. [PMID: 29806027 PMCID: PMC5969821 DOI: 10.1126/sciadv.aar5316] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 04/17/2018] [Indexed: 05/26/2023]
Abstract
Prediction of RNA structure from nucleotide sequence remains an unsolved grand challenge of biochemistry and requires distinct concepts from protein structure prediction. Despite extensive algorithmic development in recent years, modeling of noncanonical base pairs of new RNA structural motifs has not been achieved in blind challenges. We report a stepwise Monte Carlo (SWM) method with a unique add-and-delete move set that enables predictions of noncanonical base pairs of complex RNA structures. A benchmark of 82 diverse motifs establishes the method's general ability to recover noncanonical pairs ab initio, including multistrand motifs that have been refractory to prior approaches. In a blind challenge, SWM models predicted nucleotide-resolution chemical mapping and compensatory mutagenesis experiments for three in vitro selected tetraloop/receptors with previously unsolved structures (C7.2, C7.10, and R1). As a final test, SWM blindly and correctly predicted all noncanonical pairs of a Zika virus double pseudoknot during a recent community-wide RNA-Puzzle. Stepwise structure formation, as encoded in the SWM method, enables modeling of noncanonical RNA structure in a variety of previously intractable problems.
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Affiliation(s)
- Andrew M. Watkins
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Caleb Geniesse
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Wipapat Kladwang
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Paul Zakrevsky
- Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California at Santa Barbara, Santa Barbara, CA 93106, USA
| | - Luc Jaeger
- Department of Chemistry and Biochemistry, Biomolecular Science and Engineering Program, University of California at Santa Barbara, Santa Barbara, CA 93106, USA
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
- Department of Physics, Stanford University, Stanford, CA 94305, USA
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143
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Barrows NJ, Campos RK, Liao KC, Prasanth KR, Soto-Acosta R, Yeh SC, Schott-Lerner G, Pompon J, Sessions OM, Bradrick SS, Garcia-Blanco MA. Biochemistry and Molecular Biology of Flaviviruses. Chem Rev 2018; 118:4448-4482. [PMID: 29652486 DOI: 10.1021/acs.chemrev.7b00719] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Flaviviruses, such as dengue, Japanese encephalitis, tick-borne encephalitis, West Nile, yellow fever, and Zika viruses, are critically important human pathogens that sicken a staggeringly high number of humans every year. Most of these pathogens are transmitted by mosquitos, and not surprisingly, as the earth warms and human populations grow and move, their geographic reach is increasing. Flaviviruses are simple RNA-protein machines that carry out protein synthesis, genome replication, and virion packaging in close association with cellular lipid membranes. In this review, we examine the molecular biology of flaviviruses touching on the structure and function of viral components and how these interact with host factors. The latter are functionally divided into pro-viral and antiviral factors, both of which, not surprisingly, include many RNA binding proteins. In the interface between the virus and the hosts we highlight the role of a noncoding RNA produced by flaviviruses to impair antiviral host immune responses. Throughout the review, we highlight areas of intense investigation, or a need for it, and potential targets and tools to consider in the important battle against pathogenic flaviviruses.
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Affiliation(s)
- Nicholas J Barrows
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Rafael K Campos
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Kuo-Chieh Liao
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - K Reddisiva Prasanth
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Shih-Chia Yeh
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Geraldine Schott-Lerner
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Julien Pompon
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore.,MIVEGEC, IRD, CNRS, Université de Montpellier , Montpellier 34090 , France
| | - October M Sessions
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Shelton S Bradrick
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
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144
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Delorme-Axford E, Abernathy E, Lennemann NJ, Bernard A, Ariosa A, Coyne CB, Kirkegaard K, Klionsky DJ. The exoribonuclease Xrn1 is a post-transcriptional negative regulator of autophagy. Autophagy 2018; 14:898-912. [PMID: 29465287 DOI: 10.1080/15548627.2018.1441648] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Macroautophagy/autophagy is a conserved catabolic process that promotes survival during stress. Autophagic dysfunction is associated with pathologies such as cancer and neurodegenerative diseases. Thus, autophagy must be strictly modulated at multiple levels (transcriptional, post-transcriptional, translational and post-translational) to prevent deregulation. Relatively little is known about the post-transcriptional control of autophagy. Here we report that the exoribonuclease Xrn1/XRN1 functions as a negative autophagy factor in the yeast Saccharomyces cerevisiae and in mammalian cells. In yeast, chromosomal deletion of XRN1 enhances autophagy and the frequency of autophagosome formation. Loss of Xrn1 results in the upregulation of autophagy-related (ATG) transcripts under nutrient-replete conditions, and this effect is dependent on the ribonuclease activity of Xrn1. Xrn1 expression is regulated by the yeast transcription factor Ash1 in rich conditions. In mammalian cells, siRNA depletion of XRN1 enhances autophagy and the replication of 2 picornaviruses. This work provides insight into the role of the RNA decay factor Xrn1/XRN1 as a post-transcriptional regulator of autophagy.
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Affiliation(s)
| | - Emma Abernathy
- b Department of Genetics , Stanford University School of Medicine , Stanford , CA , USA
| | | | - Amélie Bernard
- a Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA
| | - Aileen Ariosa
- a Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA
| | - Carolyn B Coyne
- c Department of Pediatrics , University of Pittsburgh , Pittsburgh , PA , USA
| | - Karla Kirkegaard
- b Department of Genetics , Stanford University School of Medicine , Stanford , CA , USA
| | - Daniel J Klionsky
- a Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA
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145
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Abstract
Infection with Zika virus (ZIKV) during pregnancy may cause severe developmental defects in the human brain via unknown mechanisms. In a recent issue of Science, Chavali et al. (2017) identified a neural progenitor cell (NPC)-specific RNA binding protein that may underlie the high levels of ZIKV replication and apoptosis observed in these cells during congenital infections.
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Affiliation(s)
- Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110, USA.
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146
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Wolbachia-mediated virus blocking in mosquito cells is dependent on XRN1-mediated viral RNA degradation and influenced by viral replication rate. PLoS Pathog 2018; 14:e1006879. [PMID: 29494679 PMCID: PMC5833283 DOI: 10.1371/journal.ppat.1006879] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 01/15/2018] [Indexed: 12/14/2022] Open
Abstract
Wolbachia is currently being developed as a novel tool to block the transmission of dengue viruses (DENV) by Aedes aegypti. A number of mechanisms have been proposed to explain the DENV-blocking phenotype in mosquitoes, including competition for fatty acids like cholesterol, manipulation of host miRNAs and upregulation of innate immune pathways in the mosquito. We examined the various stages in the DENV infection process to better understand the mechanism of Wolbachia-mediated virus blocking (WMVB). Our results suggest that infection with Wolbachia does not inhibit DENV binding or cell entry, but reduces virus replication. In contrast to a previous report, we also observed a similar reduction in replication of West Nile virus (WNV). This reduced replication is associated with rapid viral RNA degradation in the cytoplasm. We didn't find a role for host miRNAs in WMVB. Further analysis showed that the 3' end of the virus subgenomic RNA was protected and accumulated over time suggesting that the degradation is XRN1-mediated. We also found that sub genomic flavivirus RNA accumulation inactivated XRN1 in mosquito cells in the absence of Wolbachia and led to enhancement of RNA degradation in its presence. Depletion of XRN1 decreased WMVB which was associated with a significant increase in DENV RNA. We also observed that WMVB is influenced by virus MOI and rate of virus replication. A comparatively elevated blocking was observed for slowly replicating DENV, compared to WNV. Similar results were obtained while analysing different DENV serotypes.
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147
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Mechanism and structural diversity of exoribonuclease-resistant RNA structures in flaviviral RNAs. Nat Commun 2018; 9:119. [PMID: 29317714 PMCID: PMC5760640 DOI: 10.1038/s41467-017-02604-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 12/12/2017] [Indexed: 01/21/2023] Open
Abstract
Flaviviruses such as Yellow fever, Dengue, West Nile, and Zika generate disease-linked viral noncoding RNAs called subgenomic flavivirus RNAs. Subgenomic flavivirus RNAs result when the 5'-3' progression of cellular exoribonuclease Xrn1 is blocked by RNA elements called Xrn1-resistant RNAs located within the viral genome's 3'-untranslated region that operate without protein co-factors. Here, we show that Xrn1-resistant RNAs can halt diverse exoribonucleases, revealing a mechanism in which they act as general mechanical blocks that 'brace' against an enzyme's surface, presenting an unfolding problem that confounds further enzyme progression. Further, we directly demonstrate that Xrn1-resistant RNAs exist in a diverse set of flaviviruses, including some specific to insects or with no known arthropod vector. These Xrn1-resistant RNAs comprise two secondary structural classes that mirror previously reported phylogenic analysis. Our discoveries have implications for the evolution of exoribonuclease resistance, the use of Xrn1-resistant RNAs in synthetic biology, and the development of new therapies.
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148
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Lim CS, Brown CM. Know Your Enemy: Successful Bioinformatic Approaches to Predict Functional RNA Structures in Viral RNAs. Front Microbiol 2018; 8:2582. [PMID: 29354101 PMCID: PMC5758548 DOI: 10.3389/fmicb.2017.02582] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/11/2017] [Indexed: 12/14/2022] Open
Abstract
Structured RNA elements may control virus replication, transcription and translation, and their distinct features are being exploited by novel antiviral strategies. Viral RNA elements continue to be discovered using combinations of experimental and computational analyses. However, the wealth of sequence data, notably from deep viral RNA sequencing, viromes, and metagenomes, necessitates computational approaches being used as an essential discovery tool. In this review, we describe practical approaches being used to discover functional RNA elements in viral genomes. In addition to success stories in new and emerging viruses, these approaches have revealed some surprising new features of well-studied viruses e.g., human immunodeficiency virus, hepatitis C virus, influenza, and dengue viruses. Some notable discoveries were facilitated by new comparative analyses of diverse viral genome alignments. Importantly, comparative approaches for finding RNA elements embedded in coding and non-coding regions differ. With the exponential growth of computer power we have progressed from stem-loop prediction on single sequences to cutting edge 3D prediction, and from command line to user friendly web interfaces. Despite these advances, many powerful, user friendly prediction tools and resources are underutilized by the virology community.
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Affiliation(s)
- Chun Shen Lim
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Chris M Brown
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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149
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Flaviviral RNA Structures and Their Role in Replication and Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:45-62. [PMID: 29845524 DOI: 10.1007/978-981-10-8727-1_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
More than simple vectors of genetic information, flaviviral RNAs have emerged as critical regulators of the virus life cycle. Viral RNAs regulate interactions with viral and cellular proteins in both, mosquito and mammalian hosts to ultimately influence processes as diverse as RNA replication, translation, packaging or pathogenicity. In this chapter, we will review the current knowledge of the role of sequence and structures in the flaviviral RNA in viral propagation and interaction with the host cell. We will also cover the increasing body of evidence linking viral non-coding RNAs with pathogenicity, host immunity and epidemic potential.
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150
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Jun SR, Wassenaar TM, Wanchai V, Patumcharoenpol P, Nookaew I, Ussery DW. Suggested mechanisms for Zika virus causing microcephaly: what do the genomes tell us? BMC Bioinformatics 2017; 18:471. [PMID: 29297281 PMCID: PMC5751795 DOI: 10.1186/s12859-017-1894-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background Zika virus (ZIKV) is an emerging human pathogen. Since its arrival in the Western hemisphere, from Africa via Asia, it has become a serious threat to pregnant women, causing microcephaly and other neuropathies in developing fetuses. The mechanisms behind these teratogenic effects are unknown, although epidemiological evidence suggests that microcephaly is not associated with the original, African lineage of ZIKV. The sequences of 196 published ZIKV genomes were used to assess whether recently proposed mechanistic explanations for microcephaly are supported by molecular level changes that may have increased its virulence since the virus left Africa. For this we performed phylogenetic, recombination, adaptive evolution and tetramer frequency analyses, and compared protein sequences for the presence of protease cleavage sites, Pfam domains, glycosylation sites, signal peptides, trans-membrane protein domains, and phosphorylation sites. Results Recombination events within or between Asian and Brazilian lineages were not observed, and likewise there were no differences in protease cleavage, glycosylation sites, signal peptides or trans-membrane domains between African and Brazilian strains. The frequency of Retinoic Acid Response Element (RARE) sequences was increased in Brazilian strains. Genetic adaptation was also apparent by tetramer signatures that had undergone major changes in the past but has stabilized in the Brazilian lineage despite subsequent geographic spread, suggesting the viral population presently propagates in the same host species in various regions. Evidence for selection pressure was recognized for several amino acid sites in the Brazilian lineage compared to the African lineage, mainly in nonstructural proteins, especially protein NS4B. A number of these positively selected mutations resulted in an increased potential to be phosphorylated in the Brazilian lineage compared to the African linage, which may have increased their potential to interfere with neural fetal development. Conclusions ZIKV seems to have adapted to a limited number of hosts, including humans, during which its virulence increased. Its protein NS4B, together with NS4A, has recently been shown to inhibit Akt-mTOR signaling in human fetal neural stem cells, a key pathway for brain development. We hypothesize that positive selection of novel phosphorylation sites in the protein NS4B of the Brazilian lineage could interfere with phosphorylation of Akt and mTOR, impairing Akt-mTOR signaling and this may result in an increased risk for developmental neuropathies. Electronic supplementary material The online version of this article (10.1186/s12859-017-1894-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Se-Ran Jun
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Trudy M Wassenaar
- Molecular Microbiology and Genomics Consultants, Zotzenheim, Germany
| | - Visanu Wanchai
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Preecha Patumcharoenpol
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Intawat Nookaew
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - David W Ussery
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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