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Li Y, Zhang L, Wang L, Li J, Zhao Y, Liu F, Wang Q. Structure and function of type IV IRES in picornaviruses: a systematic review. Front Microbiol 2024; 15:1415698. [PMID: 38855772 PMCID: PMC11157119 DOI: 10.3389/fmicb.2024.1415698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 05/13/2024] [Indexed: 06/11/2024] Open
Abstract
The Picornaviridae is a family of icosahedral viruses with single-stranded, highly diverse positive-sense RNA genomes. Virions consist of a capsid, without envelope, surrounding a core of RNA genome. A typical genome of picornavirus harbors a well-conserved and highly structured RNA element known as the internal ribosome entry site (IRES), functionally essential for viral replication and protein translation. Based on differences in their structures and mechanisms of action, picornaviral IRESs have been categorized into five types: type I, II, III, IV, and V. Compared with the type IV IRES, the others not only are structurally complicated, but also involve multiple initiation factors for triggering protein translation. The type IV IRES, often referred to as hepatitis C virus (HCV)-like IRES due to its structural resemblance to the HCV IRES, exhibits a simpler and more compact structure than those of the other four. The increasing identification of picornaviruses with the type IV IRES suggests that this IRES type seems to reveal strong retention and adaptation in terms of viral evolution. Here, we systematically reviewed structural features and biological functions of the type IV IRES in picornaviruses. A comprehensive understanding of the roles of type IV IRESs will contribute to elucidating the replication mechanism and pathogenesis of picornaviruses.
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Affiliation(s)
- Yan Li
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
- Qingdao Center for Animal Disease Control and Prevention, Qingdao, China
| | - Lei Zhang
- Shandong New Hope Liuhe Group Co., Ltd., Qingdao, China
| | - Ling Wang
- University Hospital, Qingdao Agricultural University, Qingdao, China
| | - Jing Li
- Market Supervision Administration of Huangdao District, Qingdao, China
| | - Yanwei Zhao
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Fuxiao Liu
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Qianqian Wang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
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2
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Maloney A, Joseph S. Validating the EMCV IRES Secondary Structure with Structure-Function Analysis. Biochemistry 2024; 63:107-115. [PMID: 38081770 PMCID: PMC10896073 DOI: 10.1021/acs.biochem.3c00579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The encephalomyocarditis virus internal ribosome entry site (EMCV IRES) is a structured RNA sequence found in the 5' UTR of the genomic RNA of the encephalomyocarditis virus. The EMCV IRES structure facilitates efficient translation initiation without needing a 5' m7G cap or the cap-binding protein eIF4E. The secondary structure of IRES has been the subject of several previous studies, and a number of different structural models have been proposed. Though some domains of the IRES are conserved across the different secondary structure models, domain I of the IRES varies greatly across them. A literature comparison led to the identification of three regions of interest that display structural heterogeneity within past secondary structure models. To test the accuracy of the secondary structure models in these regions, we employed mutational analysis and SHAPE probing. Mutational analysis revealed that two helical regions within the identified regions of interest are important for IRES translation. These helical regions are consistent with only one of the structure predictions in the literature and do not form in EMCV IRES structures predicted using modern secondary structure prediction methods. The importance of these regions is further supported by multiple SHAPE protections when probing was performed after in vitro translation, indicating that these regions are involved in the IRES translation complex. This work validates a published structure and demonstrates the importance of domain I during EMCV IRES translation initiation.
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Affiliation(s)
- Adam Maloney
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0314, United States
| | - Simpson Joseph
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0314, United States
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3
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Cao Y, Liu H, Lu SS, Jones KA, Govind AP, Jeyifous O, Simmons CQ, Tabatabaei N, Green WN, Holder JL, Tahmasebi S, George AL, Dickinson BC. RNA-based translation activators for targeted gene upregulation. Nat Commun 2023; 14:6827. [PMID: 37884512 PMCID: PMC10603104 DOI: 10.1038/s41467-023-42252-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023] Open
Abstract
Technologies capable of programmable translation activation offer strategies to develop therapeutics for diseases caused by insufficient gene expression. Here, we present "translation-activating RNAs" (taRNAs), a bifunctional RNA-based molecular technology that binds to a specific mRNA of interest and directly upregulates its translation. taRNAs are constructed from a variety of viral or mammalian RNA internal ribosome entry sites (IRESs) and upregulate translation for a suite of target mRNAs. We minimize the taRNA scaffold to 94 nucleotides, identify two translation initiation factor proteins responsible for taRNA activity, and validate the technology by amplifying SYNGAP1 expression, a haploinsufficiency disease target, in patient-derived cells. Finally, taRNAs are suitable for delivery as RNA molecules by lipid nanoparticles (LNPs) to cell lines, primary neurons, and mouse liver in vivo. taRNAs provide a general and compact nucleic acid-based technology to upregulate protein production from endogenous mRNAs, and may open up possibilities for therapeutic RNA research.
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Affiliation(s)
- Yang Cao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Huachun Liu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Shannon S Lu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Krysten A Jones
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Anitha P Govind
- Department of Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Okunola Jeyifous
- Department of Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Christine Q Simmons
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - William N Green
- Department of Neurobiology, The University of Chicago, Chicago, IL, USA
| | - Jimmy L Holder
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Bryan C Dickinson
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.
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4
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Dorn G, Gmeiner C, de Vries T, Dedic E, Novakovic M, Damberger FF, Maris C, Finol E, Sarnowski CP, Kohlbrecher J, Welsh TJ, Bolisetty S, Mezzenga R, Aebersold R, Leitner A, Yulikov M, Jeschke G, Allain FHT. Integrative solution structure of PTBP1-IRES complex reveals strong compaction and ordering with residual conformational flexibility. Nat Commun 2023; 14:6429. [PMID: 37833274 PMCID: PMC10576089 DOI: 10.1038/s41467-023-42012-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
RNA-binding proteins (RBPs) are crucial regulators of gene expression, often composed of defined domains interspersed with flexible, intrinsically disordered regions. Determining the structure of ribonucleoprotein (RNP) complexes involving such RBPs necessitates integrative structural modeling due to their lack of a single stable state. In this study, we integrate magnetic resonance, mass spectrometry, and small-angle scattering data to determine the solution structure of the polypyrimidine-tract binding protein 1 (PTBP1/hnRNP I) bound to an RNA fragment from the internal ribosome entry site (IRES) of the encephalomyocarditis virus (EMCV). This binding, essential for enhancing the translation of viral RNA, leads to a complex structure that demonstrates RNA and protein compaction, while maintaining pronounced conformational flexibility. Acting as an RNA chaperone, PTBP1 orchestrates the IRES RNA into a few distinct conformations, exposing the RNA stems outward. This conformational diversity is likely common among RNP structures and functionally important. Our approach enables atomic-level characterization of heterogeneous RNP structures.
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Affiliation(s)
- Georg Dorn
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Christoph Gmeiner
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland
| | - Tebbe de Vries
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Emil Dedic
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Mihajlo Novakovic
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Fred F Damberger
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Christophe Maris
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Esteban Finol
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Chris P Sarnowski
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, Villigen, Switzerland
| | - Timothy J Welsh
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland
| | - Sreenath Bolisetty
- Laboratory of Food & Soft Materials, Institute of Food, Nutrition and Health, Department for Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Raffaele Mezzenga
- Laboratory of Food & Soft Materials, Institute of Food, Nutrition and Health, Department for Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Maxim Yulikov
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich, Switzerland.
| | - Frédéric H-T Allain
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zürich, Switzerland.
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5
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Abaeva IS, Young C, Warsaba R, Khan N, Tran L, Jan E, Pestova T, Hellen CT. The structure and mechanism of action of a distinct class of dicistrovirus intergenic region IRESs. Nucleic Acids Res 2023; 51:9294-9313. [PMID: 37427788 PMCID: PMC10516663 DOI: 10.1093/nar/gkad569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/06/2023] [Accepted: 06/22/2023] [Indexed: 07/11/2023] Open
Abstract
Internal ribosomal entry sites (IRESs) engage with the eukaryotic translation apparatus to promote end-independent initiation. We identified a conserved class of ∼150 nt long intergenic region (IGR) IRESs in dicistrovirus genomes derived from members of the phyla Arthropoda, Bryozoa, Cnidaria, Echinodermata, Entoprocta, Mollusca and Porifera. These IRESs, exemplified by Wenling picorna-like virus 2, resemble the canonical cricket paralysis virus (CrPV) IGR IRES in comprising two nested pseudoknots (PKII/PKIII) and a 3'-terminal pseudoknot (PKI) that mimics a tRNA anticodon stem-loop base-paired to mRNA. However, they are ∼50 nt shorter than CrPV-like IRESs, and PKIII is an H-type pseudoknot that lacks the SLIV and SLV stem-loops that are primarily responsible for the affinity of CrPV-like IRESs for the 40S ribosomal subunit and that restrict initial binding of PKI to its aminoacyl (A) site. Wenling-class IRESs bound strongly to 80S ribosomes but only weakly to 40S subunits. Whereas CrPV-like IRESs must be translocated from the A site to the peptidyl (P) site by elongation factor 2 for elongation to commence, Wenling-class IRESs bound directly to the P site of 80S ribosomes, and decoding begins without a prior translocation step. A chimeric CrPV clone containing a Wenling-class IRES was infectious, confirming that the IRES functioned in cells.
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Affiliation(s)
- Irina S Abaeva
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Christina Young
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Reid Warsaba
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Nadiyah Khan
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Lan Vy Tran
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Eric Jan
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
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6
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Deng J, Fang X, Huang L, Li S, Xu L, Ye K, Zhang J, Zhang K, Zhang QC. RNA structure determination: From 2D to 3D. FUNDAMENTAL RESEARCH 2023; 3:727-737. [PMID: 38933295 PMCID: PMC11197651 DOI: 10.1016/j.fmre.2023.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/28/2024] Open
Abstract
RNA molecules serve a wide range of functions that are closely linked to their structures. The basic structural units of RNA consist of single- and double-stranded regions. In order to carry out advanced functions such as catalysis and ligand binding, certain types of RNAs can adopt higher-order structures. The analysis of RNA structures has progressed alongside advancements in structural biology techniques, but it comes with its own set of challenges and corresponding solutions. In this review, we will discuss recent advances in RNA structure analysis techniques, including structural probing methods, X-ray crystallography, nuclear magnetic resonance, cryo-electron microscopy, and small-angle X-ray scattering. Often, a combination of multiple techniques is employed for the integrated analysis of RNA structures. We also survey important RNA structures that have been recently determined using various techniques.
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Affiliation(s)
- Jie Deng
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - Xianyang Fang
- Beijing Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Huang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120, China
| | - Shanshan Li
- MOE Key Laboratory for Cellular Dynamics and Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Lilei Xu
- Beijing Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Keqiong Ye
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinsong Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Kaiming Zhang
- MOE Key Laboratory for Cellular Dynamics and Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Qiangfeng Cliff Zhang
- MOE Key Laboratory of Bioinformatics, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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7
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Mathez G, Cagno V. Small Molecules Targeting Viral RNA. Int J Mol Sci 2023; 24:13500. [PMID: 37686306 PMCID: PMC10487773 DOI: 10.3390/ijms241713500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
The majority of antivirals available target viral proteins; however, RNA is emerging as a new and promising antiviral target due to the presence of highly structured RNA in viral genomes fundamental for their replication cycle. Here, we discuss methods for the identification of RNA-targeting compounds, starting from the determination of RNA structures either from purified RNA or in living cells, followed by in silico screening on RNA and phenotypic assays to evaluate viral inhibition. Moreover, we review the small molecules known to target the programmed ribosomal frameshifting element of SARS-CoV-2, the internal ribosomal entry site of different viruses, and RNA elements of HIV.
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Affiliation(s)
| | - Valeria Cagno
- Institute of Microbiology, University Hospital of Lausanne, University of Lausanne, 1011 Lausanne, Switzerland
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8
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Imai S, Suzuki H, Fujiyoshi Y, Shimada I. Dynamically regulated two-site interaction of viral RNA to capture host translation initiation factor. Nat Commun 2023; 14:4977. [PMID: 37640715 PMCID: PMC10462655 DOI: 10.1038/s41467-023-40582-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 07/27/2023] [Indexed: 08/31/2023] Open
Abstract
Many RNA viruses employ internal ribosome entry sites (IRESs) in their genomic RNA to commandeer the host's translational machinery for replication. The IRES from encephalomyocarditis virus (EMCV) interacts with eukaryotic translation initiation factor 4 G (eIF4G), recruiting the ribosomal subunit for translation. Here, we analyze the three-dimensional structure of the complex composed of EMCV IRES, the HEAT1 domain fragment of eIF4G, and eIF4A, by cryo-electron microscopy. Two distinct eIF4G-interacting domains on the IRES are identified, and complex formation changes the angle therebetween. Further, we explore the dynamics of these domains by using solution NMR spectroscopy, revealing conformational equilibria in the microsecond to millisecond timescale. In the lowly-populated conformations, the base-pairing register of one domain is shifted with the structural transition of the three-way junction, as in the complex structure. Our study provides insights into the viral RNA's sophisticated strategy for optimal docking to hijack the host protein.
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Affiliation(s)
- Shunsuke Imai
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, 230-0045, Japan.
| | - Hiroshi Suzuki
- Cellular and Structural Physiology Laboratory (CeSPL), Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Laboratory (CeSPL), Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Ichio Shimada
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, 230-0045, Japan.
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
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9
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Abstract
Viruses lack the properties to replicate independently due to the limited resources encoded in their genome; therefore, they hijack the host cell machinery to replicate and survive. Picornaviruses get the prerequisite for effective protein synthesis through specific sequences known as internal ribosome entry sites (IRESs). In the past 2 decades, significant progress has been made in identifying different types of IRESs in picornaviruses. This review will discuss the past and current findings related to the five different types of IRESs and various internal ribosome entry site trans-acting factors (ITAFs) that either promote or suppress picornavirus translation and replication. Some IRESs are inefficient and thus require ITAFs. To achieve their full efficiency, they recruit various ITAFs, which enable them to translate more effectively and efficiently, except type IV IRES, which does not require any ITAFs. Although there are two kinds of ITAFs, one promotes viral IRES-dependent translation, and the second type restricts. Picornaviruses IRESs are classified into five types based on their use of sequence, ITAFs, and initiation factors. Some ITAFs regulate IRES activity by localizing to the viral replication factories in the cytoplasm. Also, some drugs, chemicals, and herbal extracts also regulate viral IRES-dependent translation and replication. Altogether, this review will elaborate on our understanding of the past and recent advancements in the IRES-dependent translation and replication of picornaviruses. IMPORTANCE The family Picornaviridae is divided into 68 genera and 158 species. The viruses belonging to this family range from public health importance, such as poliovirus, enterovirus A71, and hepatitis A virus, to animal viruses of great economic importance, such as foot-and-mouth disease virus. The genomes of picornaviruses contain 5' untranslated regions (5' UTRs), which possess crucial and highly structured stem-loops known as IRESs. IRES assemble the ribosomes and facilitate the cap-independent translation. Virus-host interaction is a hot spot for researchers, which warrants deep insight into understanding viral pathogenesis better and discovering new tools and ways for viral restriction to improve human and animal health. The cap-independent translation in the majority of picornaviruses is modulated by ITAFs, which bind to various IRES regions to initiate the translation. The discoveries of ITAFs substantially contributed to understanding viral replication behavior and enhanced our knowledge about virus-host interaction more effectively than ever before. This review discussed the various types of IRESs found in Picornaviridae, past and present discoveries regarding ITAFs, and their mechanism of action. The herbal extracts, drugs, and chemicals, which indicated their importance in controlling viruses, were also summarized. In addition, we discussed the movement of ITAFs from the nucleus to viral replication factories. We believe this review will stimulate researchers to search for more novel ITAFs, drugs, herbal extracts, and chemicals, enhancing the understanding of virus-host interaction.
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10
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Friedrich D, Marintchev A, Arthanari H. The metaphorical swiss army knife: The multitude and diverse roles of HEAT domains in eukaryotic translation initiation. Nucleic Acids Res 2022; 50:5424-5442. [PMID: 35552740 PMCID: PMC9177959 DOI: 10.1093/nar/gkac342] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Biomolecular associations forged by specific interaction among structural scaffolds are fundamental to the control and regulation of cell processes. One such structural architecture, characterized by HEAT repeats, is involved in a multitude of cellular processes, including intracellular transport, signaling, and protein synthesis. Here, we review the multitude and versatility of HEAT domains in the regulation of mRNA translation initiation. Structural and cellular biology approaches, as well as several biophysical studies, have revealed that a number of HEAT domain-mediated interactions with a host of protein factors and RNAs coordinate translation initiation. We describe the basic structural architecture of HEAT domains and briefly introduce examples of the cellular processes they dictate, including nuclear transport by importin and RNA degradation. We then focus on proteins in the translation initiation system featuring HEAT domains, specifically the HEAT domains of eIF4G, DAP5, eIF5, and eIF2Bϵ. Comparative analysis of their remarkably versatile interactions, including protein–protein and protein–RNA recognition, reveal the functional importance of flexible regions within these HEAT domains. Here we outline how HEAT domains orchestrate fundamental aspects of translation initiation and highlight open mechanistic questions in the area.
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Affiliation(s)
- Daniel Friedrich
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.,Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Assen Marintchev
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, USA
| | - Haribabu Arthanari
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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11
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Tants JN, Becker LM, McNicoll F, Müller-McNicoll M, Schlundt A. NMR-derived secondary structure of the full-length Ox40 mRNA 3'UTR and its multivalent binding to the immunoregulatory RBP Roquin. Nucleic Acids Res 2022; 50:4083-4099. [PMID: 35357505 PMCID: PMC9023295 DOI: 10.1093/nar/gkac212] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 02/24/2022] [Accepted: 03/17/2022] [Indexed: 12/31/2022] Open
Abstract
Control of posttranscriptional mRNA decay is a crucial determinant of cell homeostasis and differentiation. mRNA lifetime is governed by cis-regulatory elements in their 3′ untranslated regions (UTR). Despite ongoing progress in the identification of cis elements we have little knowledge about the functional and structural integration of multiple elements in 3′UTR regulatory hubs and their recognition by mRNA-binding proteins (RBPs). Structural analyses are complicated by inconsistent mapping and prediction of RNA fold, by dynamics, and size. We here, for the first time, provide the secondary structure of a complete mRNA 3′UTR. We use NMR spectroscopy in a divide-and-conquer strategy complemented with SAXS, In-line probing and SHAPE-seq applied to the 3′UTR of Ox40 mRNA, which encodes a T-cell co-receptor repressed by the protein Roquin. We provide contributions of RNA elements to Roquin-binding. The protein uses its extended bi-modal ROQ domain to sequentially engage in a 2:1 stoichiometry with a 3′UTR core motif. We observe differential binding of Roquin to decay elements depending on their structural embedment. Our data underpins the importance of studying RNA regulation in a full sequence and structural context. This study serves as a paradigm for an approach in analysing structured RNA-regulatory hubs and their binding by RBPs.
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Affiliation(s)
- Jan-Niklas Tants
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Lea Marie Becker
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - François McNicoll
- Goethe University Frankfurt, Institute for Molecular Biosciences, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - Michaela Müller-McNicoll
- Goethe University Frankfurt, Institute for Molecular Biosciences, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - Andreas Schlundt
- Goethe University Frankfurt, Institute for Molecular Biosciences and Biomagnetic Resonance Centre (BMRZ), Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
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12
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Francisco-Velilla R, Embarc-Buh A, Abellan S, Martinez-Salas E. Picornavirus translation strategies. FEBS Open Bio 2022; 12:1125-1141. [PMID: 35313388 PMCID: PMC9157412 DOI: 10.1002/2211-5463.13400] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/02/2022] [Accepted: 03/18/2022] [Indexed: 12/15/2022] Open
Abstract
The genome of viruses classified as picornaviruses consists of a single monocistronic positive strand RNA. The coding capacity of these RNA viruses is rather limited, and thus, they rely on the cellular machinery for their viral replication cycle. Upon the entry of the virus into susceptible cells, the viral RNA initially competes with cellular mRNAs for access to the protein synthesis machinery. Not surprisingly, picornaviruses have evolved specialized strategies that successfully allow the expression of viral gene products, which we outline in this review. The main feature of all picornavirus genomes is the presence of a heavily structured RNA element on the 5´UTR, referred to as an internal ribosome entry site (IRES) element, which directs viral protein synthesis as well and, consequently, triggers the subsequent steps required for viral replication. Here, we will summarize recent studies showing that picornavirus IRES elements consist of a modular structure, providing sites of interaction for ribosome subunits, eIFs, and a selective group of RNA‐binding proteins.
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Affiliation(s)
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
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13
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Abstract
In recent years, it has become clear that RNA molecules are involved in almost all vital cellular processes and pathogenesis of human disorders. The functional diversity of RNA comes from its structural richness. Although composed of only four nucleotides, RNA molecules present a plethora of secondary and tertiary structures critical for intra and intermolecular contacts with other RNAs and ligands (proteins, small metabolites, etc.). In order to fully understand RNA function it is necessary to define its spatial structure. Crystallography, nuclear magnetic resonance and cryogenic electron microscopy have demonstrated considerable success in determining the structures of biologically important RNA molecules. However, these powerful methods require large amounts of sample. Despite their limitations, chemical synthesis and in vitro transcription are usually employed to obtain milligram quantities of RNA for structural studies, delivering simple and effective methods for large-scale production of homogenous samples. The aim of this paper is to provide an overview of methods for large-scale RNA synthesis with emphasis on chemical synthesis and in vitro transcription. We also present our own results of testing the efficiency of these approaches in order to adapt the material acquisition strategy depending on the desired RNA construct.
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14
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Arhab Y, Miścicka A, Pestova TV, Hellen CUT. Horizontal gene transfer as a mechanism for the promiscuous acquisition of distinct classes of IRES by avian caliciviruses. Nucleic Acids Res 2021; 50:1052-1068. [PMID: 34928389 PMCID: PMC8789048 DOI: 10.1093/nar/gkab1243] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/17/2021] [Accepted: 12/15/2021] [Indexed: 02/05/2023] Open
Abstract
In contrast to members of Picornaviridae which have long 5'-untranslated regions (5'UTRs) containing internal ribosomal entry sites (IRESs) that form five distinct classes, members of Caliciviridae typically have short 5'UTRs and initiation of translation on them is mediated by interaction of the viral 5'-terminal genome-linked protein (VPg) with subunits of eIF4F rather than by an IRES. The recent description of calicivirus genomes with 500-900nt long 5'UTRs was therefore unexpected and prompted us to examine them in detail. Sequence analysis and structural modelling of the atypically long 5'UTRs of Caliciviridae sp. isolate yc-13 and six other caliciviruses suggested that they contain picornavirus-like type 2 IRESs, whereas ruddy turnstone calicivirus (RTCV) and Caliciviridae sp. isolate hwf182cal1 calicivirus contain type 4 and type 5 IRESs, respectively. The suggestion that initiation on RTCV mRNA occurs by the type 4 IRES mechanism was confirmed experimentally using in vitro reconstitution. The high sequence identity between identified calicivirus IRESs and specific picornavirus IRESs suggests a common evolutionary origin. These calicivirus IRESs occur in a single phylogenetic branch of Caliciviridae and were likely acquired by horizontal gene transfer.
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Affiliation(s)
- Yani Arhab
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn NY 11203, USA
| | - Anna Miścicka
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn NY 11203, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn NY 11203, USA
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15
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Dagenais P, Desjardins G, Legault P. An integrative NMR-SAXS approach for structural determination of large RNAs defines the substrate-free state of a trans-cleaving Neurospora Varkud Satellite ribozyme. Nucleic Acids Res 2021; 49:11959-11973. [PMID: 34718697 PMCID: PMC8599749 DOI: 10.1093/nar/gkab963] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 09/01/2021] [Accepted: 10/26/2021] [Indexed: 11/26/2022] Open
Abstract
The divide-and-conquer strategy is commonly used for protein structure determination, but its applications to high-resolution structure determination of RNAs have been limited. Here, we introduce an integrative approach based on the divide-and-conquer strategy that was undertaken to determine the solution structure of an RNA model system, the Neurospora VS ribozyme. NMR and SAXS studies were conducted on a minimal trans VS ribozyme as well as several isolated subdomains. A multi-step procedure was used for structure determination that first involved pairing refined NMR structures with SAXS data to obtain structural subensembles of the various subdomains. These subdomain structures were then assembled to build a large set of structural models of the ribozyme, which was subsequently filtered using SAXS data. The resulting NMR-SAXS structural ensemble shares several similarities with the reported crystal structures of the VS ribozyme. However, a local structural difference is observed that affects the global fold by shifting the relative orientation of the two three-way junctions. Thus, this finding highlights a global conformational change associated with substrate binding in the VS ribozyme that is likely critical for its enzymatic activity. Structural studies of other large RNAs should benefit from similar integrative approaches that allow conformational sampling of assembled fragments.
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Affiliation(s)
- Pierre Dagenais
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Box 6128, Downtown Station, Montreal, QC H3C 3J7, Quebec, Canada
| | - Geneviève Desjardins
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Box 6128, Downtown Station, Montreal, QC H3C 3J7, Quebec, Canada
| | - Pascale Legault
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Box 6128, Downtown Station, Montreal, QC H3C 3J7, Quebec, Canada
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16
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Akhzari S, Nabian S, Shayan P, Fard RMN, Soltani M, Taheri M. Designing of RNA Molecule Translating for Activitable Melittin as Selective Targeting of Leishmania Infected Cells. IRANIAN JOURNAL OF PARASITOLOGY 2021; 16:443-453. [PMID: 34630590 PMCID: PMC8476729 DOI: 10.18502/ijpa.v16i3.7098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/10/2021] [Indexed: 11/24/2022]
Abstract
Background Leishmaniasis is characterized by strong inflammatory responses with high levels of inflammatory cytokines that induce microRNA 21 and matrix metalloproteinases. Melittin has inhibitory effects on proliferation of various cells via induction of apoptosis. Melittin can be integrated in cell membranes and induce apoptosis. Thus, designation of biomolecules for the selective destroy of the infected cells is a treatment option. One approach is the precise engineering of constructs for the selective expression of melittin in the infected cells. Methods For this aim we designed a construct composing melittin nucleotide sequence and nucleotide sequence coding for polyanionic peptide function inhibitory element to further guarantee the selective function of melittin in inflamed tissues and infected cells, were included in a construct as melittin inhibitor via matrix metalloproteinase degradable linker. Results Reverse complementary sequences were designed so melittin sequences for the selective targeting of Leishmania could be expressed in infected cells using cell microRNA machinery. Conclusion Translation machinery in infected cells with increased miR-21 could translate melittin, MMP linker and polyanionic inhibitor through a non-canonical pathway. Then, the MMP linker is degraded and selective killing of Leishmania infected cells would happen.
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Affiliation(s)
- Soheila Akhzari
- Department of Parasitology, School of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Sedigheh Nabian
- Department of Parasitology, School of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Parviz Shayan
- Department of Parasitology, School of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Ramin Mazaheri Nezhad Fard
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Minoo Soltani
- Department of Microbiology and Immunology, School of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Mohammad Taheri
- Rastegar Reference Laboratory, School of Veterinary Medicine, University of Tehran, Tehran, Iran
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17
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Liu Y, Kotar A, Hodges TL, Abdallah K, Taleb MH, Bitterman BA, Jaime S, Schaubroeck KJ, Mathew E, Morgenstern NW, Lohmeier A, Page JL, Ratanapanichkich M, Arhin G, Johnson BL, Cherepanov S, Moss SC, Zuniga G, Tilson NJ, Yeoh ZC, Johnson BA, Keane SC. NMR chemical shift assignments of RNA oligonucleotides to expand the RNA chemical shift database. BIOMOLECULAR NMR ASSIGNMENTS 2021; 15:479-490. [PMID: 34449019 DOI: 10.1007/s12104-021-10049-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
RNAs play myriad functional and regulatory roles in the cell. Despite their significance, three-dimensional structure elucidation of RNA molecules lags significantly behind that of proteins. NMR-based studies are often rate-limited by the assignment of chemical shifts. Automation of the chemical shift assignment process can greatly facilitate structural studies, however, accurate chemical shift predictions rely on a robust and complete chemical shift database for training. We searched the Biological Magnetic Resonance Data Bank (BMRB) to identify sequences that had no (or limited) chemical shift information. Here, we report the chemical shift assignments for 12 RNA hairpins designed specifically to help populate the BMRB.
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Affiliation(s)
- Yaping Liu
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Anita Kotar
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
- Current Address: Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Tracy L Hodges
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Kyrillos Abdallah
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Mallak H Taleb
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Brayden A Bitterman
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Sara Jaime
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Kyle J Schaubroeck
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Ethan Mathew
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Nicholas W Morgenstern
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Anthony Lohmeier
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Jordan L Page
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Matt Ratanapanichkich
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Grace Arhin
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Breanna L Johnson
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Stanislav Cherepanov
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Stephen C Moss
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Gisselle Zuniga
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Nicholas J Tilson
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA
| | - Zoe C Yeoh
- Department of Biological Chemistry, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI, 48109, USA
| | - Bruce A Johnson
- Structural Biology Initiative, CUNY Advanced Science Research Center, 85 St. Nicholas Terrace, New York, NY, 10031, USA
| | - Sarah C Keane
- Biophysics Program, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA.
- Department of Chemistry, University of Michigan, 930 N. University Avenue, Ann Arbor, MI, 48109, USA.
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18
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Trainor BM, Ghosh A, Pestov DG, Hellen CUT, Shcherbik N. A translation enhancer element from black beetle virus engages yeast eIF4G1 to drive cap-independent translation initiation. Sci Rep 2021; 11:2461. [PMID: 33510277 PMCID: PMC7844027 DOI: 10.1038/s41598-021-82025-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/14/2021] [Indexed: 01/13/2023] Open
Abstract
Cap-independent translation initiation plays crucial roles in fine-tuning gene expression under global translation shutdown conditions. Translation of uncapped or de-capped transcripts can be stimulated by Cap-independent translation enhancer (CITE) elements, but the mechanisms of CITE-mediated translation initiation remain understudied. Here, we characterized a short 5ʹ-UTR RNA sequence from black beetle virus, BBV-seq. Mutational analysis indicates that the entire BBV-seq is required for efficient translation initiation, but this sequence does not operate as an IRES-type module. In yeast cell-free translation extracts, BBV-seq promoted efficient initiation on cap-free mRNA using a scanning mechanism. Moreover, BBV-seq can increase translation efficiency resulting from conventional cap-dependent translation initiation. Using genetic approaches, we found that BBV-seq exploits RNA-binding properties of eIF4G1 to promote initiation. Thus, BBV-seq constitutes a previously uncharacterized short, linear CITE that influences eIF4G1 to initiate 5′ end-dependent, cap-independent translation. These findings bring new insights into CITE-mediated translational control of gene expression.
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Affiliation(s)
- Brandon M Trainor
- Department of Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, 2 Medical Center Drive, Stratford, NJ, 08084, USA.,Graduate School of Biomedical Sciences, Rowan University, 42 E. Laurel Road, Suite 2200, Stratford, NJ, 08084, USA
| | - Arnab Ghosh
- Department of Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, 2 Medical Center Drive, Stratford, NJ, 08084, USA.,Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Ave, Cleveland, OH, 44115, USA
| | - Dimitri G Pestov
- Department of Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, 2 Medical Center Drive, Stratford, NJ, 08084, USA
| | - Christopher U T Hellen
- Department of Cell Biology, State University of New York Downstate Health Sciences University, 450 Clarkson Avenue MSC 44, Brooklyn, NY, 11203, USA
| | - Natalia Shcherbik
- Department of Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, 2 Medical Center Drive, Stratford, NJ, 08084, USA.
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19
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Abaeva IS, Vicens Q, Bochler A, Soufari H, Simonetti A, Pestova TV, Hashem Y, Hellen CUT. The Halastavi árva Virus Intergenic Region IRES Promotes Translation by the Simplest Possible Initiation Mechanism. Cell Rep 2020; 33:108476. [PMID: 33296660 DOI: 10.1016/j.celrep.2020.108476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/05/2020] [Accepted: 11/12/2020] [Indexed: 01/01/2023] Open
Abstract
Dicistrovirus intergenic region internal ribosomal entry sites (IGR IRESs) do not require initiator tRNA, an AUG codon, or initiation factors and jumpstart translation from the middle of the elongation cycle via formation of IRES/80S complexes resembling the pre-translocation state. eEF2 then translocates the [codon-anticodon]-mimicking pseudoknot I (PKI) from ribosomal A sites to P sites, bringing the first sense codon into the decoding center. Halastavi árva virus (HalV) contains an IGR that is related to previously described IGR IRESs but lacks domain 2, which enables these IRESs to bind to individual 40S ribosomal subunits. By using in vitro reconstitution and cryoelectron microscopy (cryo-EM), we now report that the HalV IGR IRES functions by the simplest initiation mechanism that involves binding to 80S ribosomes such that PKI is placed in the P site, so that the A site contains the first codon that is directly accessible for decoding without prior eEF2-mediated translocation of PKI.
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Affiliation(s)
- Irina S Abaeva
- Department of Cell Biology, SUNY Downstate Health Sciences University, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA
| | - Quentin Vicens
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, 15 rue René Descartes, 67000 Strasbourg, France
| | - Anthony Bochler
- INSERM U1212 Acides Nucléiques: Régulations Naturelle et Artificielle, Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France; Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, 15 rue René Descartes, 67000 Strasbourg, France
| | - Heddy Soufari
- INSERM U1212 Acides Nucléiques: Régulations Naturelle et Artificielle, Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Angelita Simonetti
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, 15 rue René Descartes, 67000 Strasbourg, France
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA.
| | - Yaser Hashem
- INSERM U1212 Acides Nucléiques: Régulations Naturelle et Artificielle, Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France.
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA.
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20
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Nobuta R, Machida K, Sato M, Hashimoto S, Toriumi Y, Nakajima S, Suto D, Imataka H, Inada T. eIF4G-driven translation initiation of downstream ORFs in mammalian cells. Nucleic Acids Res 2020; 48:10441-10455. [PMID: 32941651 PMCID: PMC7544200 DOI: 10.1093/nar/gkaa728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 12/24/2022] Open
Abstract
Comprehensive genome-wide analysis has revealed the presence of translational elements in the 3′ untranslated regions (UTRs) of human transcripts. However, the mechanisms by which translation is initiated in 3′ UTRs and the physiological function of their products remain unclear. This study showed that eIF4G drives the translation of various downstream open reading frames (dORFs) in 3′ UTRs. The 3′ UTR of GCH1, which encodes GTP cyclohydrolase 1, contains an internal ribosome entry site (IRES) that initiates the translation of dORFs. An in vitro reconstituted translation system showed that the IRES in the 3′ UTR of GCH1 required eIF4G and conventional translation initiation factors, except eIF4E, for AUG-initiated translation of dORFs. The 3′ UTR of GCH1-mediated translation was resistant to the mTOR inhibitor Torin 1, which inhibits cap-dependent initiation by increasing eIF4E-unbound eIF4G. eIF4G was also required for the activity of various elements, including polyU and poliovirus type 2, a short element thought to recruit ribosomes by base-pairing with 18S rRNA. These findings indicate that eIF4G mediates translation initiation of various ORFs in mammalian cells, suggesting that the 3′ UTRs of mRNAs may encode various products.
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Affiliation(s)
- Risa Nobuta
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Kodai Machida
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Himeji 671-2280, Japan
| | - Misaki Sato
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Satoshi Hashimoto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Yasuhito Toriumi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Shizuka Nakajima
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Daiki Suto
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Hiroaki Imataka
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, Himeji 671-2280, Japan
| | - Toshifumi Inada
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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21
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Advanced approaches for elucidating structures of large RNAs using NMR spectroscopy and complementary methods. Methods 2020; 183:93-107. [DOI: 10.1016/j.ymeth.2020.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/11/2019] [Accepted: 01/16/2020] [Indexed: 11/23/2022] Open
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22
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Boyd PS, Brown JB, Brown JD, Catazaro J, Chaudry I, Ding P, Dong X, Marchant J, O’Hern CT, Singh K, Swanson C, Summers MF, Yasin S. NMR Studies of Retroviral Genome Packaging. Viruses 2020; 12:v12101115. [PMID: 33008123 PMCID: PMC7599994 DOI: 10.3390/v12101115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/03/2022] Open
Abstract
Nearly all retroviruses selectively package two copies of their unspliced RNA genomes from a cellular milieu that contains a substantial excess of non-viral and spliced viral RNAs. Over the past four decades, combinations of genetic experiments, phylogenetic analyses, nucleotide accessibility mapping, in silico RNA structure predictions, and biophysical experiments were employed to understand how retroviral genomes are selected for packaging. Genetic studies provided early clues regarding the protein and RNA elements required for packaging, and nucleotide accessibility mapping experiments provided insights into the secondary structures of functionally important elements in the genome. Three-dimensional structural determinants of packaging were primarily derived by nuclear magnetic resonance (NMR) spectroscopy. A key advantage of NMR, relative to other methods for determining biomolecular structure (such as X-ray crystallography), is that it is well suited for studies of conformationally dynamic and heterogeneous systems—a hallmark of the retrovirus packaging machinery. Here, we review advances in understanding of the structures, dynamics, and interactions of the proteins and RNA elements involved in retroviral genome selection and packaging that are facilitated by NMR.
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23
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Schnieders R, Knezic B, Zetzsche H, Sudakov A, Matzel T, Richter C, Hengesbach M, Schwalbe H, Fürtig B. NMR Spectroscopy of Large Functional RNAs: From Sample Preparation to Low-Gamma Detection. ACTA ACUST UNITED AC 2020; 82:e116. [PMID: 32960489 DOI: 10.1002/cpnc.116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
NMR spectroscopy is a potent method for the structural and biophysical characterization of RNAs. The application of NMR spectroscopy is restricted in RNA size and most often requires isotope-labeled or even selectively labeled RNAs. Additionally, new NMR pulse sequences, such as the heteronuclear-detected NMR experiments, are introduced. We herein provide detailed protocols for the preparation of isotope-labeled RNA for NMR spectroscopy via in vitro transcription. This protocol covers all steps, from the preparation of DNA template to the transcription of milligram RNA quantities. Moreover, we present a protocol for a chemo-enzymatic approach to introduce a single modified nucleotide at any position of any RNA. Regarding NMR methodology, we share protocols for the implementation of a suite of heteronuclear-detected NMR experiments including 13 C-detected experiments for ribose assignment and amino groups, the CN-spin filter heteronuclear single quantum coherence (HSQC) for imino groups and the 15 N-detected band-selective excitation short transient transverse-relaxation-optimized spectroscopy (BEST-TROSY) experiment. © 2020 The Authors. Basic Protocol 1: Preparation of isotope-labeled RNA samples with in vitro transcription using T7 RNAP, DEAE chromatography, and RP-HPLC purification Alternate Protocol 1: Purification of isotope-labeled RNA from in vitro transcription with preparative PAGE Alternate Protocol 2: Purification of isotope-labeled RNA samples from in vitro transcription via centrifugal concentration Support Protocol 1: Preparation of DNA template from plasmid Support Protocol 2: Preparation of PCR DNA as template Support Protocol 3: Preparation of T7 RNA Polymerase (T7 RNAP) Support Protocol 4: Preparation of yeast inorganic pyrophosphatase (YIPP) Basic Protocol 2: Preparation of site-specific labeled RNAs using a chemo-enzymatic synthesis Support Protocol 5: Synthesis of modified nucleoside 3',5'-bisphosphates Support Protocol 6: Preparation of T4 RNA Ligase 2 Support Protocol 7: Setup of NMR spectrometer for heteronuclear-detected NMR experiments Support Protocol 8: IPAP and DIPAP for homonuclear decoupling Basic Protocol 3: 13 C-detected 3D (H)CC-TOCSY, (H)CPC, and (H)CPC-CCH-TOCSY experiments for ribose assignment Basic Protocol 4: 13 C-detected 2D CN-spin filter HSQC experiment Basic Protocol 5: 13 C-detected C(N)H-HDQC experiment for the detection of amino groups Support Protocol 9: 13 C-detected CN-HSQC experiment for amino groups Basic Protocol 6: 13 C-detected "amino"-NOESY experiment Basic Protocol 7: 15 N-detected BEST-TROSY experiment.
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Affiliation(s)
- Robbin Schnieders
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Bozana Knezic
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Heidi Zetzsche
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Alexey Sudakov
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Tobias Matzel
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Christian Richter
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Martin Hengesbach
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University, Germany
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24
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Lyons SM, Kharel P, Akiyama Y, Ojha S, Dave D, Tsvetkov V, Merrick W, Ivanov P, Anderson P. eIF4G has intrinsic G-quadruplex binding activity that is required for tiRNA function. Nucleic Acids Res 2020; 48:6223-6233. [PMID: 32374873 PMCID: PMC7293036 DOI: 10.1093/nar/gkaa336] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/20/2020] [Accepted: 05/04/2020] [Indexed: 12/13/2022] Open
Abstract
As cells encounter adverse environmental conditions, such as hypoxia, oxidative stress or nutrient deprivation, they trigger stress response pathways to protect themselves until transient stresses have passed. Inhibition of translation is a key component of such cellular stress responses and mounting evidence has revealed the importance of a class of tRNA-derived small RNAs called tiRNAs in this process. The most potent of these small RNAs are those with the capability of assembling into tetrameric G-quadruplex (G4) structures. However, the mechanism by which these small RNAs inhibit translation has yet to be elucidated. Here we show that eIF4G, the major scaffolding protein in the translation initiation complex, directly binds G4s and this activity is required for tiRNA-mediated translation repression. Targeting of eIF4G results in an impairment of 40S ribosome scanning on mRNAs leading to the formation of eIF2α-independent stress granules. Our data reveals the mechanism by which tiRNAs inhibit translation and demonstrates novel activity for eIF4G in the regulation of translation.
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Affiliation(s)
- Shawn M Lyons
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA.,Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.,The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Prakash Kharel
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Yasutoshi Akiyama
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA.,Laboratory of Oncology, Pharmacy Practice and Sciences, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan
| | - Sandeep Ojha
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.,The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Dhwani Dave
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
| | - Vladimir Tsvetkov
- Computational Oncology Group, I.M. Sechenov First Moscow State Medical University , Moscow, Russia.,Federal Research and Clinical Center forPhysical-Chemical Medicine, Federal Medical Biological Agency, Moscow, Russia.,A. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia
| | - William Merrick
- Department of Biochemistry, Case Western ReserveUniversity, Cleveland, OH, USA
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Paul Anderson
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.,Department of Medicine, Harvard Medical School, Boston, MA, USA
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25
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Abramov G, Velyvis A, Rennella E, Wong LE, Kay LE. A methyl-TROSY approach for NMR studies of high-molecular-weight DNA with application to the nucleosome core particle. Proc Natl Acad Sci U S A 2020; 117:12836-12846. [PMID: 32457157 PMCID: PMC7293644 DOI: 10.1073/pnas.2004317117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of methyl-transverse relaxation-optimized spectroscopy (methyl-TROSY)-based NMR methods, in concert with robust strategies for incorporation of methyl-group probes of structure and dynamics into the protein of interest, has facilitated quantitative studies of high-molecular-weight protein complexes. Here we develop a one-pot in vitro reaction for producing NMR quantities of methyl-labeled DNA at the C5 and N6 positions of cytosine (5mC) and adenine (6mA) nucleobases, respectively, enabling the study of high-molecular-weight DNA molecules using TROSY approaches originally developed for protein applications. Our biosynthetic strategy exploits the large number of naturally available methyltransferases to specifically methylate DNA at a desired number of sites that serve as probes of structure and dynamics. We illustrate the methodology with studies of the 153-base pair Widom DNA molecule that is simultaneously methyl-labeled at five sites, showing that high-quality 13C-1H spectra can be recorded on 100 μM samples in a few minutes. NMR spin relaxation studies of labeled methyl groups in both DNA and the H2B histone protein component of the 200-kDa nucleosome core particle (NCP) establish that methyl groups at 5mC and 6mA positions are, in general, more rigid than Ile, Leu, and Val methyl probes in protein side chains. Studies focusing on histone H2B of NCPs wrapped with either wild-type DNA or DNA methylated at all 26 CpG sites highlight the utility of NMR in investigating the structural dynamics of the NCP and how its histone core is affected through DNA methylation, an important regulator of transcription.
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Affiliation(s)
- Gili Abramov
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Algirdas Velyvis
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Bioscience Department, Syngenta, Jealott's Hill Research Centre, Bracknell RG42 6EY, United Kingdom
| | - Enrico Rennella
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leo E Wong
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lewis E Kay
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada;
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
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26
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Arhab Y, Bulakhov AG, Pestova TV, Hellen CU. Dissemination of Internal Ribosomal Entry Sites (IRES) Between Viruses by Horizontal Gene Transfer. Viruses 2020; 12:v12060612. [PMID: 32512856 PMCID: PMC7354566 DOI: 10.3390/v12060612] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
Members of Picornaviridae and of the Hepacivirus, Pegivirus and Pestivirus genera of Flaviviridae all contain an internal ribosomal entry site (IRES) in the 5'-untranslated region (5'UTR) of their genomes. Each class of IRES has a conserved structure and promotes 5'-end-independent initiation of translation by a different mechanism. Picornavirus 5'UTRs, including the IRES, evolve independently of other parts of the genome and can move between genomes, most commonly by intratypic recombination. We review accumulating evidence that IRESs are genetic entities that can also move between members of different genera and even between families. Type IV IRESs, first identified in the Hepacivirus genus, have subsequently been identified in over 25 genera of Picornaviridae, juxtaposed against diverse coding sequences. In several genera, members have either type IV IRES or an IRES of type I, II or III. Similarly, in the genus Pegivirus, members contain either a type IV IRES or an unrelated type; both classes of IRES also occur in members of the genus Hepacivirus. IRESs utilize different mechanisms, have different factor requirements and contain determinants of viral growth, pathogenesis and cell type specificity. Their dissemination between viruses by horizontal gene transfer has unexpectedly emerged as an important facet of viral evolution.
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27
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Asadi-Atoi P, Barraud P, Tisne C, Kellner S. Benefits of stable isotope labeling in RNA analysis. Biol Chem 2020; 400:847-865. [PMID: 30893050 DOI: 10.1515/hsz-2018-0447] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
RNAs are key players in life as they connect the genetic code (DNA) with all cellular processes dominated by proteins. They contain a variety of chemical modifications and many RNAs fold into complex structures. Here, we review recent progress in the analysis of RNA modification and structure on the basis of stable isotope labeling techniques. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are the key tools and many breakthrough developments were made possible by the analysis of stable isotope labeled RNA. Therefore, we discuss current stable isotope labeling techniques such as metabolic labeling, enzymatic labeling and chemical synthesis. RNA structure analysis by NMR is challenging due to two major problems that become even more salient when the size of the RNA increases, namely chemical shift overlaps and line broadening leading to complete signal loss. Several isotope labeling strategies have been developed to provide solutions to these major issues, such as deuteration, segmental isotope labeling or site-specific labeling. Quantification of modified nucleosides in RNA by MS is only possible through the application of stable isotope labeled internal standards. With nucleic acid isotope labeling coupled mass spectrometry (NAIL-MS), it is now possible to analyze the dynamic processes of post-transcriptional RNA modification and demodification. The trend, in both NMR and MS RNA analytics, is without doubt shifting from the analysis of snapshot moments towards the development and application of tools capable of analyzing the dynamics of RNA structure and modification profiles.
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Affiliation(s)
- Paria Asadi-Atoi
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
| | - Pierre Barraud
- Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, F-75005 Paris, France
| | - Carine Tisne
- Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, F-75005 Paris, France
| | - Stefanie Kellner
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, D-81377 Munich, Germany
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28
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Abstract
Viruses must co-opt the cellular translation machinery to produce progeny virions. Eukaryotic viruses have evolved a variety of ways to manipulate the cellular translation apparatus, in many cases using elegant RNA-centred strategies. Viral RNAs can alter or control every phase of protein synthesis and have diverse targets, mechanisms and structures. In addition, as cells attempt to limit infection by downregulating translation, some of these viral RNAs enable the virus to overcome this response or even take advantage of it to promote viral translation over cellular translation. In this Review, we present important examples of viral RNA-based strategies to exploit the cellular translation machinery. We describe what is understood of the structures and mechanisms of diverse viral RNA elements that alter or regulate translation, the advantages that are conferred to the virus and some of the major unknowns that provide motivation for further exploration. Eukaryotic viruses have evolved a variety of ways to manipulate the cellular translation apparatus. In this Review, Jaafar and Kieft present important examples of viral RNA-based strategies to exploit the cellular translation machinery.
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Affiliation(s)
- Zane A Jaafar
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO, USA. .,RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, CO, USA.
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29
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Wennesz R, Luttermann C, Kreher F, Meyers G. Structure-function relationship in the 'termination upstream ribosomal binding site' of the calicivirus rabbit hemorrhagic disease virus. Nucleic Acids Res 2019; 47:1920-1934. [PMID: 30668745 PMCID: PMC6393290 DOI: 10.1093/nar/gkz021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/04/2019] [Accepted: 01/10/2019] [Indexed: 12/12/2022] Open
Abstract
Caliciviruses use a termination/reinitiation mechanism for translation of their minor capsid protein VP2. A sequence element of about 80 nucleotides denoted ‘termination upstream ribosomal binding site’ (TURBS) is crucial for reinitiation. RNA secondary structure probing and computer aided secondary structure prediction revealed a rather low degree of secondary structure determinants for the TURBS of the rabbit hermorrhagic disease virus. Mutation analysis showed that prevention of duplex formation had major impact on the VP2 expression levels. Restoration of complementarity of the respective sequences by reciprocal mutation at least partially restored reinitiating rates. Synthetic TURBS structures preserving only the secondary structure forming sequences and the known short motifs important for TURBS function were found to drive reinitiation when the altered sequence could be predicted to allow establishment of the crucial secondary structures of the TURBS.
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Affiliation(s)
- René Wennesz
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Christine Luttermann
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Felix Kreher
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
| | - Gregor Meyers
- Institut für Immunologie, Friedrich-Loeffler-Institut, D-17493 Greifswald-Insel Riems, Germany
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30
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Koirala D, Shao Y, Koldobskaya Y, Fuller JR, Watkins AM, Shelke SA, Pilipenko EV, Das R, Rice PA, Piccirilli JA. A conserved RNA structural motif for organizing topology within picornaviral internal ribosome entry sites. Nat Commun 2019; 10:3629. [PMID: 31399592 PMCID: PMC6689051 DOI: 10.1038/s41467-019-11585-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 07/09/2019] [Indexed: 12/30/2022] Open
Abstract
Picornaviral IRES elements are essential for initiating the cap-independent viral translation. However, three-dimensional structures of these elements remain elusive. Here, we report a 2.84-Å resolution crystal structure of hepatitis A virus IRES domain V (dV) in complex with a synthetic antibody fragment-a crystallization chaperone. The RNA adopts a three-way junction structure, topologically organized by an adenine-rich stem-loop motif. Despite no obvious sequence homology, the dV architecture shows a striking similarity to a circularly permuted form of encephalomyocarditis virus J-K domain, suggesting a conserved strategy for organizing the domain architecture. Recurrence of the motif led us to use homology modeling tools to compute a 3-dimensional structure of the corresponding domain of foot-and-mouth disease virus, revealing an analogous domain organizing motif. The topological conservation observed among these IRESs and other viral domains implicates a structured three-way junction as an architectural scaffold to pre-organize helical domains for recruiting the translation initiation machinery.
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Affiliation(s)
- Deepak Koirala
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Yaming Shao
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Yelena Koldobskaya
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - James R Fuller
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Andrew M Watkins
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Sandip A Shelke
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Evgeny V Pilipenko
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA. .,Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA.
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31
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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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32
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The 3' Untranslated Region of a Plant Viral RNA Directs Efficient Cap-Independent Translation in Plant and Mammalian Systems. Pathogens 2019; 8:pathogens8010028. [PMID: 30823456 PMCID: PMC6471432 DOI: 10.3390/pathogens8010028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/03/2019] [Accepted: 02/23/2019] [Indexed: 11/29/2022] Open
Abstract
Many plant viral RNA genomes lack a 5′ cap, and instead are translated via a cap-independent translation element (CITE) in the 3′ untranslated region (UTR). The panicum mosaic virus-like CITE (PTE), found in many plant viral RNAs, binds and requires the cap-binding translation initiation factor eIF4E to facilitate translation. eIF4E is structurally conserved between plants and animals, so we tested cap-independent translation efficiency of PTEs of nine plant viruses in plant and mammalian systems. The PTE from thin paspalum asymptomatic virus (TPAV) facilitated efficient cap-independent translation in wheat germ extract, rabbit reticulocyte lysate, HeLa cell lysate, and in oat and mammalian (BHK) cells. Human eIF4E bound the TPAV PTE but not a PTE that did not stimulate cap-independent translation in mammalian extracts or cells. Selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE) footprinting revealed that both human and wheat eIF4E protected the conserved guanosine (G)-rich domain in the TPAV PTE pseudoknot. The central G plays a key role, as it was found to be required for translation and protection from SHAPE modification by eIF4E. These results provide insight on how plant viruses gain access to the host’s translational machinery, an essential step in infection, and raise the possibility that similar PTE-like mechanisms may exist in mRNAs of mammals or their viruses.
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33
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Lozano G, Francisco-Velilla R, Martinez-Salas E. Deconstructing internal ribosome entry site elements: an update of structural motifs and functional divergences. Open Biol 2018; 8:rsob.180155. [PMID: 30487301 PMCID: PMC6282068 DOI: 10.1098/rsob.180155] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/30/2018] [Indexed: 12/16/2022] Open
Abstract
Beyond the general cap-dependent translation initiation, eukaryotic organisms use alternative mechanisms to initiate protein synthesis. Internal ribosome entry site (IRES) elements are cis-acting RNA regions that promote internal initiation of translation using a cap-independent mechanism. However, their lack of primary sequence and secondary RNA structure conservation, as well as the diversity of host factor requirement to recruit the ribosomal subunits, suggest distinct types of IRES elements. In spite of this heterogeneity, conserved motifs preserve sequences impacting on RNA structure and RNA–protein interactions important for IRES-driven translation. This conservation brings the question of whether IRES elements could consist of basic building blocks, which upon evolutionary selection result in functional elements with different properties. Although RNA-binding proteins (RBPs) perform a crucial role in the assembly of ribonucleoprotein complexes, the versatility and plasticity of RNA molecules, together with their high flexibility and dynamism, determines formation of macromolecular complexes in response to different signals. These properties rely on the presence of short RNA motifs, which operate as modular entities, and suggest that decomposition of IRES elements in short modules could help to understand the different mechanisms driven by these regulatory elements. Here we will review evidence suggesting that model IRES elements consist of the combination of short modules, providing sites of interaction for ribosome subunits, eIFs and RBPs, with implications for definition of criteria to identify novel IRES-like elements genome wide.
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Affiliation(s)
- Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain
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34
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Ribosome-dependent conformational flexibility changes and RNA dynamics of IRES domains revealed by differential SHAPE. Sci Rep 2018; 8:5545. [PMID: 29615727 PMCID: PMC5882922 DOI: 10.1038/s41598-018-23845-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/21/2018] [Indexed: 12/11/2022] Open
Abstract
Internal ribosome entry site (IRES) elements are RNA regions that recruit the translation machinery internally. Here we investigated the conformational changes and RNA dynamics of a picornavirus IRES upon incubation with distinct ribosomal fractions. Differential SHAPE analysis of the free RNA showed that nucleotides reaching the final conformation on long timescales were placed at domains 4 and 5, while candidates for long-range interactions were located in domain 3. Salt-washed ribosomes induced a fast RNA local flexibility modification of domains 2 and 3, while ribosome-associated factors changed domains 4 and 5. Consistent with this, modeling of the three-dimensional RNA structure indicated that incubation of the IRES with native ribosomes induced a local rearrangement of the apical region of domain 3, and a reorientation of domains 4 and 5. Furthermore, specific motifs within domains 2 and 3 showed a decreased flexibility upon incubation with ribosomal subunits in vitro, and presence of the IRES enhanced mRNA association to the ribosomal subunits in whole cell lysates. The finding that RNA modules can provide direct IRES-ribosome interaction suggests that linking these motifs to additional sequences able to recruit trans-acting factors could be useful to design synthetic IRESs with novel activities.
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35
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Mailliot J, Martin F. Viral internal ribosomal entry sites: four classes for one goal. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9. [PMID: 29193740 DOI: 10.1002/wrna.1458] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/19/2017] [Accepted: 10/02/2017] [Indexed: 12/22/2022]
Abstract
To ensure efficient propagation, viruses need to rapidly produce viral proteins after cell entrance. Since viral genomes do not encode any components of the protein biosynthesis machinery, viral proteins must be produced by the host cell. To hi-jack the host cellular translation, viruses use a great variety of distinct strategies. Many single-stranded positive-sensed RNA viruses contain so-called internal ribosome entry sites (IRESs). IRESs are structural RNA motifs that have evolved to specific folds that recruit the host ribosomes on the viral coding sequences in order to synthesize viral proteins. In host canonical translation, recruitment of the translation machinery components is essentially guided by the 5' cap (m7 G) of mRNA. In contrast, IRESs are able to promote efficient ribosome assembly internally and in cap-independent manner. IRESs have been categorized into four classes, based on their length, nucleotide sequence, secondary and tertiary structures, as well as their mode of action. Classes I and II require the assistance of cellular auxiliary factors, the eukaryotic intiation factors (eIF), for efficient ribosome assembly. Class III IRESs require only a subset of eIFs whereas Class IV, which are the more compact, can promote translation without any eIFs. Extensive functional and structural investigations of IRESs over the past decades have allowed a better understanding of their mode of action for viral translation. Because viral translation has a pivotal role in the infectious program, IRESs are therefore attractive targets for therapeutic purposes. WIREs RNA 2018, 9:e1458. doi: 10.1002/wrna.1458 This article is categorized under: Translation > Ribosome Structure/Function Translation > Translation Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Justine Mailliot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Illkirch-Graffenstaden, France
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN" CNRS UPR9002, Université De Strasbourg, Strasbourg, France
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36
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Martinez-Salas E, Francisco-Velilla R, Fernandez-Chamorro J, Embarek AM. Insights into Structural and Mechanistic Features of Viral IRES Elements. Front Microbiol 2018; 8:2629. [PMID: 29354113 PMCID: PMC5759354 DOI: 10.3389/fmicb.2017.02629] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/15/2017] [Indexed: 01/19/2023] Open
Abstract
Internal ribosome entry site (IRES) elements are cis-acting RNA regions that promote internal initiation of protein synthesis using cap-independent mechanisms. However, distinct types of IRES elements present in the genome of various RNA viruses perform the same function despite lacking conservation of sequence and secondary RNA structure. Likewise, IRES elements differ in host factor requirement to recruit the ribosomal subunits. In spite of this diversity, evolutionarily conserved motifs in each family of RNA viruses preserve sequences impacting on RNA structure and RNA–protein interactions important for IRES activity. Indeed, IRES elements adopting remarkable different structural organizations contain RNA structural motifs that play an essential role in recruiting ribosomes, initiation factors and/or RNA-binding proteins using different mechanisms. Therefore, given that a universal IRES motif remains elusive, it is critical to understand how diverse structural motifs deliver functions relevant for IRES activity. This will be useful for understanding the molecular mechanisms beyond cap-independent translation, as well as the evolutionary history of these regulatory elements. Moreover, it could improve the accuracy to predict IRES-like motifs hidden in genome sequences. This review summarizes recent advances on the diversity and biological relevance of RNA structural motifs for viral IRES elements.
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Affiliation(s)
- Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
| | - Azman M Embarek
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Madrid, Spain
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Schnieders R, Richter C, Warhaut S, de Jesus V, Keyhani S, Duchardt-Ferner E, Keller H, Wöhnert J, Kuhn LT, Breeze AL, Bermel W, Schwalbe H, Fürtig B. Evaluation of 15N-detected H-N correlation experiments on increasingly large RNAs. JOURNAL OF BIOMOLECULAR NMR 2017; 69:31-44. [PMID: 28879611 DOI: 10.1007/s10858-017-0132-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Recently, 15N-detected multidimensional NMR experiments have been introduced for the investigation of proteins. Utilization of the slow transverse relaxation of nitrogen nuclei in a 15N-TROSY experiment allowed recording of high quality spectra for high molecular weight proteins, even in the absence of deuteration. Here, we demonstrate the applicability of three 15N-detected H-N correlation experiments (TROSY, BEST-TROSY and HSQC) to RNA. With the newly established 15N-detected BEST-TROSY experiment, which proves to be the most sensitive 15N-detected H-N correlation experiment, spectra for five RNA molecules ranging in size from 5 to 100 kDa were recorded. These spectra yielded high resolution in the 15N-dimension even for larger RNAs since the increase in line width with molecular weight is more pronounced in the 1H- than in the 15N-dimension. Further, we could experimentally validate the difference in relaxation behavior of imino groups in AU and GC base pairs. Additionally, we showed that 15N-detected experiments theoretically should benefit from sensitivity and resolution advantages at higher static fields but that the latter is obscured by exchange dynamics within the RNAs.
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Affiliation(s)
- Robbin Schnieders
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Christian Richter
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Sven Warhaut
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Vanessa de Jesus
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Sara Keyhani
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany
| | - Elke Duchardt-Ferner
- Institute for Molecular Biosciences, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt, Germany
| | - Heiko Keller
- Institute for Molecular Biosciences, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt, Germany
| | - Jens Wöhnert
- Institute for Molecular Biosciences, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt, Germany
| | - Lars T Kuhn
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Alexander L Breeze
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Silberstreifen 4, 76287, Rheinstetten, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
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38
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Yamamoto H, Unbehaun A, Spahn CMT. Ribosomal Chamber Music: Toward an Understanding of IRES Mechanisms. Trends Biochem Sci 2017; 42:655-668. [PMID: 28684008 DOI: 10.1016/j.tibs.2017.06.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 12/31/2022]
Abstract
Internal initiation is a 5'-end-independent mode of translation initiation engaged by many virus- and putatively some cell-encoded templates. Internal initiation is facilitated by specific RNA tertiary folds, called internal ribosomal entry sites (IRESs), in the 5' untranslated region (UTR) of the respective transcripts. In this review we discuss recent structural insight into how established IRESs first capture and then manipulate the eukaryotic translation machinery through non-canonical interactions and by guiding the intrinsic conformational flexibility of the eukaryotic ribosome. Because IRESs operate with reduced complexity and constitute minimal systems of initiation, comparison with canonical initiation may allow common mechanistic principles of the ribosome to be delineated.
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Affiliation(s)
- Hiroshi Yamamoto
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany
| | - Anett Unbehaun
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian M T Spahn
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Medizinische Physik und Biophysik, Charitéplatz 1, 10117 Berlin, Germany.
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39
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Applications of NMR to structure determination of RNAs large and small. Arch Biochem Biophys 2017; 628:42-56. [PMID: 28600200 DOI: 10.1016/j.abb.2017.06.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/31/2017] [Accepted: 06/04/2017] [Indexed: 02/07/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to investigate the structure and dynamics of RNA, because many biologically important RNAs have conformationally flexible structures, which makes them difficult to crystallize. Functional, independently folded RNA domains, range in size between simple stem-loops of as few as 10-20 nucleotides, to 50-70 nucleotides, the size of tRNA and many small ribozymes, to a few hundred nucleotides, the size of more complex RNA enzymes and of the functional domains of non-coding transcripts. In this review, we discuss new methods for sample preparation, assignment strategies and structure determination for independently folded RNA domains of up to 100 kDa in molecular weight.
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40
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Regulation Mechanisms of Viral IRES-Driven Translation. Trends Microbiol 2017; 25:546-561. [PMID: 28242053 DOI: 10.1016/j.tim.2017.01.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/10/2017] [Accepted: 01/30/2017] [Indexed: 02/06/2023]
Abstract
Internal ribosome entry sites (IRESs) can be found in the mRNA of many viruses as well as in cellular genes involved in the stress response, cell cycle, and apoptosis. IRES-mediated translation can occur when dominant cap-dependent translation is inhibited, and viruses can take advantage of this to subvert host translation machinery. In this review, we focus on the four major types of IRES identified in RNA viruses, and outline their distinct structural properties and requirements of translational factors. We further discuss auxiliary host factors known as IRES trans-acting factors (ITAFs), which are involved in the modulation of optimal IRES activity. Currently known strategies employed by viruses to harness ITAFs and regulate IRES activity are also highlighted.
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