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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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Abaeva IS, Pestova TV, Hellen CUT. Genetic mechanisms underlying the structural elaboration and dissemination of viral internal ribosomal entry sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.590008. [PMID: 38883778 PMCID: PMC11178006 DOI: 10.1101/2024.04.17.590008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Viral internal ribosomal entry sites (IRESs) form several classes that use distinct mechanisms to mediate end-independent initiation of translation. The origin of viral IRESs is a longstanding question. The simplest IRESs comprise tandem pseudoknots and occur in the intergenic region (IGR) of Dicistroviridae genomes (order Picornavirales ). Larger IGR IRESs contain additional elements that determine specific properties such as binding to the head of the ribosoma l 40S subunit. Metagenomic analyses reported here identified novel groups of structurally distinct IGR-like IRESs. The smallest of these (∼120nt long) comprise three pseudoknots and bind directly to the ribosomal P site. Others are up to 260nt long: insertions occurred at specific loci, possibly reflecting non-templated nucleotide insertion during replication. Various groups can be arranged in order, differing by the cumulative addition of single structural elements, suggesting an accretion mechanism for the structural elaboration of IRESs. Identification of chimeric IRESs implicates recombinational exchange of domains as a second mechanism for the diversification of IRES structure. Recombination likely also accounts for the presence of IGR-like IRESs at the 5'-end of some dicistrovirus-like genomes (e.g. Hangzhou dicistrovirus 3) and in the RNA genomes of Tombusviridae (order Tolivirales ), Marnaviridae (order Picornavirale s), and the 'Ripiresk' picorna-like clade (order Picornavirale s).
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3
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Boros Á, Pankovics P, László Z, Urbán P, Herczeg R, Gáspár G, Tóth F, Reuter G. The genomic and epidemiological investigations of enteric viruses of domestic caprine ( Capra hircus) revealed the presence of multiple novel viruses related to known strains of humans and ruminant livestock species. Microbiol Spectr 2023; 11:e0253323. [PMID: 37823638 PMCID: PMC10714811 DOI: 10.1128/spectrum.02533-23] [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: 06/16/2023] [Accepted: 09/04/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Compared with other domestic animals, the virome and viral diversity of small ruminants especially in caprine are less studied even of its zoonotic potential. In this study, the enteric virome of caprine was investigated in detail using next-generation sequencing and reverse transcription PCR techniques. The complete or nearly complete genomes of seven novel viruses were determined which show a close phylogenetic relationship to known human and ruminant viruses. The high similarity between the identified caprine tusavirus (family Parvoviridae) and an unassigned CRESS DNA virus with closely related human strains could indicate the (reverse) zoonotic potential of these viruses. Others, like astroviruses (family Astroviridae), enteroviruses, or novel caripiviruses (named after the term caprine picornavirus) of family Picornaviridae found mostly in multiple co-infections in caprine and ovine, could indicate the cross-species transmission capabilities of these viruses between small ruminants.
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Affiliation(s)
- Ákos Boros
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Pankovics
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Zoltán László
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Urbán
- János Szentágothai Research Centre of the University of Pécs, Bioinformatics Research Group, Genomics and Bioinformatics Core Facility, Pécs, Hungary
| | - Róbert Herczeg
- János Szentágothai Research Centre of the University of Pécs, Bioinformatics Research Group, Genomics and Bioinformatics Core Facility, Pécs, Hungary
| | - Gábor Gáspár
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Fruzsina Tóth
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Gábor Reuter
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
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4
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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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5
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Wang X, Zhu J, Zhang D, Liu G. Ribosomal control in RNA virus-infected cells. Front Microbiol 2022; 13:1026887. [PMID: 36419416 PMCID: PMC9677555 DOI: 10.3389/fmicb.2022.1026887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
Viruses are strictly intracellular parasites requiring host cellular functions to complete their reproduction cycle involving virus infection of host cell, viral genome replication, viral protein translation, and virion release. Ribosomes are protein synthesis factories in cells, and viruses need to manipulate ribosomes to complete their protein synthesis. Viruses use translation initiation factors through their own RNA structures or cap structures, thereby inducing ribosomes to synthesize viral proteins. Viruses also affect ribosome production and the assembly of mature ribosomes, and regulate the recognition of mRNA by ribosomes, thereby promoting viral protein synthesis and inhibiting the synthesis of host antiviral immune proteins. Here, we review the remarkable mechanisms used by RNA viruses to regulate ribosomes, in particular, the mechanisms by which RNA viruses induce the formation of specific heterogeneous ribosomes required for viral protein translation. This review provides valuable insights into the control of viral infection and diseases from the perspective of viral protein synthesis.
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6
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Sadic M, Schneider WM, Katsara O, Medina GN, Fisher A, Mogulothu A, Yu Y, Gu M, de los Santos T, Schneider RJ, Dittmann M. DDX60 selectively reduces translation off viral type II internal ribosome entry sites. EMBO Rep 2022; 23:e55218. [PMID: 36256515 PMCID: PMC9724679 DOI: 10.15252/embr.202255218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 11/05/2022] Open
Abstract
Co-opting host cell protein synthesis is a hallmark of many virus infections. In response, certain host defense proteins limit mRNA translation globally, albeit at the cost of the host cell's own protein synthesis. Here, we describe an interferon-stimulated helicase, DDX60, that decreases translation from viral internal ribosome entry sites (IRESs). DDX60 acts selectively on type II IRESs of encephalomyocarditis virus (EMCV) and foot and mouth disease virus (FMDV), but not by other IRES types or by 5' cap. Correspondingly, DDX60 reduces EMCV and FMDV (type II IRES) replication, but not that of poliovirus or bovine enterovirus 1 (BEV-1; type I IRES). Furthermore, replacing the IRES of poliovirus with a type II IRES is sufficient for DDX60 to inhibit viral replication. Finally, DDX60 selectively modulates the amount of translating ribosomes on viral and in vitro transcribed type II IRES mRNAs, but not 5' capped mRNA. Our study identifies a novel facet in the repertoire of interferon-stimulated effector genes, the selective downregulation of translation from viral type II IRES elements.
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Affiliation(s)
| | | | | | - Gisselle N Medina
- Plum Island Animal Disease Center, ARSUSDAGreenportNYUSA,National Bio and Agro‐Defense Facility (NBAF), ARSUSDAManhattanKSUSA
| | | | - Aishwarya Mogulothu
- Plum Island Animal Disease Center, ARSUSDAGreenportNYUSA,Department of Pathobiology and Veterinary ScienceUniversity of ConnecticutStorrsCTUSA
| | - Yingpu Yu
- The Rockefeller UniversityNew YorkNYUSA
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7
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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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8
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Oba M, Sakaguchi S, Wu H, Fujioka Y, Takemae H, Oki H, Kawai M, Shiokawa M, Aoki H, Fukase Y, Madarame H, Nakano T, Mizutani T, Nagai M. First isolation and genomic characterization of bovine parechovirus from faecal samples of cattle in Japan. J Gen Virol 2022; 103. [PMID: 35138239 DOI: 10.1099/jgv.0.001718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel picornavirus was isolated from the faeces of a diarrhoeic cow using MA-104 cells at the third blind passage. This virus, named Den1/2021/JPN, was completely sequenced using total RNA from the cell culture supernatant by deep sequencing. The genome of Den1/2021/JPN had a standard picornavirus genome organisation with conserved picornaviral motifs. The 5' untranslated region harboured a type-II internal ribosomal entry site. Den1/2021/JPN was most closely related to a bovine parechovirus (Bo_ParV) named cow/2018/4, which has been recently identified in publicly available databases. Phylogenetic analyses and pairwise sequence comparison revealed that Den1/2021/JPN and Bo_ParV cow/2018/4 clustered with parechoviruses and were most closely related to Parechovirus E identified in birds of prey, exhibiting nucleotide sequence similarity of 64.2-64.5 %, 58.6-59.7 % and 66.3-66.4 % in the polyprotein, P1 and 2C+3 CD coding regions, respectively. This study presents the first report on the isolation of Bo_ParV. Den1/2021/JPN and Bo_ParV cow/2018/4, which are candidates for a novel species in the genus Parechovirus.
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Affiliation(s)
- Mami Oba
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa 252-5201, Japan.,Center for Infectious Disease Epidemiology and Prevention Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Shoichi Sakaguchi
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Hong Wu
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Yoshihiko Fujioka
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Hitoshi Takemae
- Center for Infectious Disease Epidemiology and Prevention Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Hisako Oki
- Ishikawa Nanbu Livestock Hygiene Service Center, Kanazawa, Ishikawa 920-3101, Japan
| | - Megumi Kawai
- Ishikawa Nanbu Livestock Hygiene Service Center, Kanazawa, Ishikawa 920-3101, Japan
| | - Mai Shiokawa
- Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Musashino, Tokyo 180-8602, Japan
| | - Hiroshi Aoki
- Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Musashino, Tokyo 180-8602, Japan
| | - Yuka Fukase
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa 252-5201, Japan
| | - Hiroo Madarame
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa 252-5201, Japan
| | - Takashi Nakano
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka 569-8686, Japan
| | - Tetsuya Mizutani
- Center for Infectious Disease Epidemiology and Prevention Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Makoto Nagai
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa 252-5201, Japan.,Center for Infectious Disease Epidemiology and Prevention Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
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9
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Burgess HM, Vink EI, Mohr I. Minding the message: tactics controlling RNA decay, modification, and translation in virus-infected cells. Genes Dev 2022; 36:108-132. [PMID: 35193946 PMCID: PMC8887129 DOI: 10.1101/gad.349276.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With their categorical requirement for host ribosomes to translate mRNA, viruses provide a wealth of genetically tractable models to investigate how gene expression is remodeled post-transcriptionally by infection-triggered biological stress. By co-opting and subverting cellular pathways that control mRNA decay, modification, and translation, the global landscape of post-transcriptional processes is swiftly reshaped by virus-encoded factors. Concurrent host cell-intrinsic countermeasures likewise conscript post-transcriptional strategies to mobilize critical innate immune defenses. Here we review strategies and mechanisms that control mRNA decay, modification, and translation in animal virus-infected cells. Besides settling infection outcomes, post-transcriptional gene regulation in virus-infected cells epitomizes fundamental physiological stress responses in health and disease.
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Affiliation(s)
- Hannah M Burgess
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Elizabeth I Vink
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA
| | - Ian Mohr
- Department of Microbiology, New York University School of Medicine, New York, New York 10016, USA.,Laura and Isaac Perlmutter Cancer Institute, New York University School of Medicine, New York, New York 10016, USA
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10
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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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11
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Sweeney TR, Dhote V, Guca E, Hellen CUT, Hashem Y, Pestova T. Functional role and ribosomal position of the unique N-terminal region of DHX29, a factor required for initiation on structured mammalian mRNAs. Nucleic Acids Res 2021; 49:12955-12969. [PMID: 34883515 PMCID: PMC8682770 DOI: 10.1093/nar/gkab1192] [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: 09/29/2021] [Revised: 11/12/2021] [Accepted: 11/22/2021] [Indexed: 02/05/2023] Open
Abstract
Translation initiation on structured mammalian mRNAs requires DHX29, a DExH protein that comprises a unique 534-aa-long N-terminal region (NTR) and a common catalytic DExH core. DHX29 binds to 40S subunits and possesses 40S-stimulated NTPase activity essential for its function. In the cryo-EM structure of DHX29-bound 43S preinitiation complexes, the main DHX29 density resides around the tip of helix 16 of 18S rRNA, from which it extends through a linker to the subunit interface forming an intersubunit domain next to the eIF1A binding site. Although a DExH core model can be fitted to the main density, the correlation between the remaining density and the NTR is unknown. Here, we present a model of 40S-bound DHX29, supported by directed hydroxyl radical cleavage data, showing that the intersubunit domain comprises a dsRNA-binding domain (dsRBD, aa 377-448) whereas linker corresponds to the long α-helix (aa 460-512) that follows the dsRBD. We also demonstrate that the N-terminal α-helix and the following UBA-like domain form a four-helix bundle (aa 90-166) that constitutes a previously unassigned section of the main density and resides between DHX29's C-terminal α-helix and the linker. In vitro reconstitution experiments revealed the critical and specific roles of these NTR elements for DHX29's function.
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Affiliation(s)
- Trevor R Sweeney
- Correspondence may also be addressed to Trevor R. Sweeney. Tel: +44 1483232441; Fax: +44 1483232448;
| | | | - Ewelina Guca
- INSERM U1212 Acides nucléiques : Régulations Naturelle et Artificielle (ARNA), 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
| | - Yaser Hashem
- Correspondence may also be addressed to Yaser Hashem. Tel: +33 5 40 00 88 22;
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12
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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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13
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Barrera A, Olguín V, Vera-Otarola J, López-Lastra M. Cap-independent translation initiation of the unspliced RNA of retroviruses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194583. [PMID: 32450258 DOI: 10.1016/j.bbagrm.2020.194583] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 12/12/2022]
Abstract
Retroviruses are a unique family of RNA viruses that utilize a virally encoded reverse transcriptase (RT) to replicate their genomic RNA (gRNA) through a proviral DNA intermediate. The provirus is permanently integrated into the host cell chromosome and is expressed by the host cell transcription, RNA processing, and translation machinery. Retroviral messenger RNAs (mRNAs) entirely resemble a cellular mRNA as they have a 5'cap structure, 5'untranslated region (UTR), an open reading frame (ORF), 3'UTR, and a 3'poly(A) tail. The primary transcription product interacts with the cellular RNA processing machinery and is spliced, exported to the cytoplasm, and translated. However, a proportion of the pre-mRNA subverts typical RNA processing giving rise to the full-length RNA. In the cytoplasm, the full-length retroviral RNA fulfills a dual role acting as mRNA and as the gRNA. Simple retroviruses generate two pools of full-length RNA, one for each purpose. However, complex retroviruses have a single pool of full-length RNA, which is destined for translation or encapsidation. As for eukaryotic mRNAs, translational control of retroviral protein synthesis is mostly exerted at the step of initiation. Interestingly, some retroviral mRNAs, both simple and complex, use a dual mechanism to initiate protein synthesis, a cap-dependent initiation mechanism, or via internal initiation using an internal ribosome entry site (IRES). In this review, we describe and discuss data regarding the molecular mechanism driving the canonical cap-dependent and IRES-mediated translation initiation for retroviral mRNA, focusing the discussion mainly on the most studied retroviral mRNA, the HIV-1 mRNA.
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Affiliation(s)
- Aldo Barrera
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Valeria Olguín
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
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14
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Sanford TJ, Mears HV, Fajardo T, Locker N, Sweeney TR. Circularization of flavivirus genomic RNA inhibits de novo translation initiation. Nucleic Acids Res 2019; 47:9789-9802. [PMID: 31392996 PMCID: PMC6765113 DOI: 10.1093/nar/gkz686] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022] Open
Abstract
Members of the Flaviviridae family, including dengue virus (DENV) and yellow fever virus, cause serious disease in humans, whilst maternal infection with Zika virus (ZIKV) can induce microcephaly in newborns. Following infection, flaviviral RNA genomes are translated to produce the viral replication machinery but must then serve as a template for the transcription of new genomes. However, the ribosome and viral polymerase proceed in opposite directions along the RNA, risking collisions and abortive replication. Whilst generally linear, flavivirus genomes can adopt a circular conformation facilitated by long-range RNA–RNA interactions, shown to be essential for replication. Using an in vitro reconstitution approach, we demonstrate that circularization inhibits de novo translation initiation on ZIKV and DENV RNA, whilst the linear conformation is translation-competent. Our results provide a mechanism to clear the viral RNA of ribosomes in order to promote efficient replication and, therefore, define opposing roles for linear and circular conformations of the flavivirus genome.
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Affiliation(s)
- Thomas J Sanford
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Harriet V Mears
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Teodoro Fajardo
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7HX, UK
| | - Trevor R Sweeney
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
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15
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Holmes AC, Semler BL. Picornaviruses and RNA Metabolism: Local and Global Effects of Infection. J Virol 2019; 93:e02088-17. [PMID: 31413128 PMCID: PMC6803262 DOI: 10.1128/jvi.02088-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/06/2019] [Indexed: 11/20/2022] Open
Abstract
Due to the limiting coding capacity for members of the Picornaviridae family of positive-strand RNA viruses, their successful replication cycles require complex interactions with host cell functions. These interactions span from the down-modulation of many aspects of cellular metabolism to the hijacking of specific host functions used during viral translation, RNA replication, and other steps of infection by picornaviruses, such as human rhinovirus, coxsackievirus, poliovirus, foot-and-mouth disease virus, enterovirus D-68, and a wide range of other human and nonhuman viruses. Although picornaviruses replicate exclusively in the cytoplasm of infected cells, they have extensive interactions with host cell nuclei and the proteins and RNAs that normally reside in this compartment of the cell. This review will highlight some of the more recent studies that have revealed how picornavirus infections impact the RNA metabolism of the host cell posttranscriptionally and how they usurp and modify host RNA binding proteins as well as microRNAs to potentiate viral replication.
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Affiliation(s)
- Autumn C Holmes
- Department of Microbiology & Molecular Genetics, University of California, Irvine, California, USA
- Center for Virus Research, University of California, Irvine, California, USA
| | - Bert L Semler
- Department of Microbiology & Molecular Genetics, University of California, Irvine, California, USA
- Center for Virus Research, University of California, Irvine, California, USA
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16
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Stern-Ginossar N, Thompson SR, Mathews MB, Mohr I. Translational Control in Virus-Infected Cells. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033001. [PMID: 29891561 DOI: 10.1101/cshperspect.a033001] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
As obligate intracellular parasites, virus reproduction requires host cell functions. Despite variations in genome size and configuration, nucleic acid composition, and their repertoire of encoded functions, all viruses remain unconditionally dependent on the protein synthesis machinery resident within their cellular hosts to translate viral messenger RNAs (mRNAs). A complex signaling network responsive to physiological stress, including infection, regulates host translation factors and ribosome availability. Furthermore, access to the translation apparatus is patrolled by powerful host immune defenses programmed to restrict viral invaders. Here, we review the tactics and mechanisms used by viruses to appropriate control over host ribosomes, subvert host defenses, and dominate the infected cell translational landscape. These not only define aspects of infection biology paramount for virus reproduction, but continue to drive fundamental discoveries into how cellular protein synthesis is controlled in health and disease.
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Affiliation(s)
- Noam Stern-Ginossar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sunnie R Thompson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Michael B Mathews
- Department of Medicine, Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Ian Mohr
- Department of Microbiology, New York University School of Medicine, New York, New York 10016
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17
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Sunaga F, Masuda T, Ito M, Akagami M, Naoi Y, Sano K, Katayama Y, Omatsu T, Oba M, Sakaguchi S, Furuya T, Yamasato H, Ouchi Y, Shirai J, Mizutani T, Nagai M. Complete genomic analysis and molecular characterization of Japanese porcine sapeloviruses. Virus Genes 2019; 55:198-208. [PMID: 30712153 DOI: 10.1007/s11262-019-01640-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/21/2019] [Indexed: 01/08/2023]
Abstract
The Porcine Sapelovirus (PSV) is an enteric virus of pigs that can cause various disorders. However, there are few reports that describe the molecular characteristics of the PSV genome. In this study, almost the entire genomes of 23 PSVs detected in Japanese pigs were analyzed using bioinformatics. Analysis of the cis-active RNA elements showed that the predicted secondary structures of the internal ribosome entry site in the 5' untranslated region (UTR) and a cis-replication element in the 2C coding region were conserved among PSVs. In contrast, those at the 3' UTR were different for different PSVs; however, tertiary structures between domains were conserved across all PSVs. Phylogenetic analysis of nucleotide sequences of the complete VP1 region showed that PSVs exhibited sequence diversity; however, they could not be grouped into genotypes due to the low bootstrap support of clusters. The insertion and/or deletion patterns in the C-terminal VP1 region were not related to the topology of the VP1 tree. The 3CD phylogenetic tree was topologically different from the VP1 tree, and PSVs from the same country were clustered independently. Recombination analysis revealed that recombination events were found upstream of the P2 region and some recombination breakpoints involved insertions and/or deletions in the C-terminal VP1 region. These findings demonstrate that PSVs show genetic diversity and frequent recombination events, particularly in the region upstream of the P2 region; however, PSVs could currently not be classified into genotypes and conserved genetic structural features of the cis-active RNA elements are observed across all PSVs.
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Affiliation(s)
- Fujiko Sunaga
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan
| | - Tsuneyuki Masuda
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori, 683-0017, Japan
| | - Mika Ito
- Ishikawa Nanbu Livestock Hygiene Service Center, Kanazawa, Ishikawa, 920-3101, Japan
| | - Masataka Akagami
- Kenpoku Livestock Hygiene Service Center, Mito, Ibaraki, 310-0002, Japan
| | - Yuki Naoi
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Kaori Sano
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Yukie Katayama
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Tsutomu Omatsu
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Mami Oba
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Shoichi Sakaguchi
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan.,Department of Microbiology and Infection Control, Osaka Medical College, Osaka, 569-8686, Japan
| | - Tetsuya Furuya
- Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Hiroshi Yamasato
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori, 683-0017, Japan
| | - Yoshinao Ouchi
- Kenpoku Livestock Hygiene Service Center, Mito, Ibaraki, 310-0002, Japan
| | - Junsuke Shirai
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan.,Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Tetsuya Mizutani
- Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan
| | - Makoto Nagai
- School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan. .,Research and Education Center for Prevention of Global Infectious Disease of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, Tokyo, 183-8509, Japan.
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18
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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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19
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Oba M, Naoi Y, Ito M, Masuda T, Katayama Y, Sakaguchi S, Omatsu T, Furuya T, Yamasato H, Sunaga F, Makino S, Mizutani T, Nagai M. Metagenomic identification and sequence analysis of a Teschovirus A-related virus in porcine feces in Japan, 2014-2016. INFECTION GENETICS AND EVOLUTION 2018; 66:210-216. [PMID: 30316885 DOI: 10.1016/j.meegid.2018.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/01/2018] [Accepted: 10/10/2018] [Indexed: 01/04/2023]
Abstract
Porcine Teschoviruses (PTVs) are associated with polioencephalomyelitis and various diseases, including reproductive and gastrointestinal disorders, of pigs and wild boars, and are also detected in the feces of healthy pigs. The genus Teschovirus contains a single species Teschovirus A that currently includes 13 serotypes. In the present study, we identified novel PTVs that are distantly related to Teschovirus A and were found in fecal samples of pigs with or without diarrhea in Japan. Phylogenetic analysis of amino acid (aa) sequences of the complete coding region revealed that these newly identified viruses did not cluster with any strains of PTVs or other strains within the picornavirus supergroup 1, suggesting that the viruses may not belong to Teschovirus A or any genus of the family Picornaviridae. These novel PTVs share a type IV internal ribosomal entry site and conserved characteristic motifs in the coding region, yet exhibit 62.2-79.0%, 86.6-92.8%, 77.1-81.0%, and 84.3-86.7% aa identities to PTV strains in P1, 2C, 3C, and 3D regions, respectively. In contrast, PTV 1-13 strains of the Teschovirus A share 76.5-92.1%, 88.1-99.7%, 93.2-100%, and 95.8-100% aa identities in the P1, 2C, 3C, and 3D, respectively, within the species. These data imply that the newly identified viruses belong to teschoviruses, and may represent a novel species in the genus Teschovirus.
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Affiliation(s)
- Mami Oba
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Yuki Naoi
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Mika Ito
- Ishikawa Nanbu Livestock Hygiene Service Center, Kanazawa, Ishikawa 920-3101, Japan
| | - Tsuneyuki Masuda
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori 683-0017, Japan
| | - Yukie Katayama
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Shoichi Sakaguchi
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Tsutomu Omatsu
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Tetsuya Furuya
- Laboratory of Veterinary Microbiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Hiroshi Yamasato
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori 683-0017, Japan
| | - Fujiko Sunaga
- Laboratory of Infectious Diseases, Azabu University, Sagamihara, Kanagawa 252-5201, Japan
| | - Shinji Makino
- Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, United States
| | - Tetsuya Mizutani
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.
| | - Makoto Nagai
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan; Laboratory of Infectious Diseases, Azabu University, Sagamihara, Kanagawa 252-5201, Japan.
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20
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Chen JH, Zhang RH, Lin SL, Li PF, Lan JJ, Song SS, Gao JM, Wang Y, Xie ZJ, Li FC, Jiang SJ. The Functional Role of the 3' Untranslated Region and Poly(A) Tail of Duck Hepatitis A Virus Type 1 in Viral Replication and Regulation of IRES-Mediated Translation. Front Microbiol 2018; 9:2250. [PMID: 30319572 PMCID: PMC6167517 DOI: 10.3389/fmicb.2018.02250] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 09/04/2018] [Indexed: 01/04/2023] Open
Abstract
The duck hepatitis A virus type 1 (DHAV-1) is a member of Picornaviridae family, the genome of the virus contains a 5′ untranslated region (5′ UTR), a large open reading frame that encodes a polyprotein precursor and a 3′ UTR followed by a poly(A) tail. The translation initiation of virus proteins depends on the internal ribosome-entry site (IRES) element within the 5′ UTR. So far, little information is known about the role of the 3′ UTR and poly(A) tail during the virus proliferation. In this study, the function of the 3′ UTR and poly(A) tail of DHAV-1 in viral replication and IRES-mediated translation was investigated. The results showed that both 3′ UTR and poly(A) tail are important for maintaining viral genome RNA stability and viral genome replication. During DHAV-1 proliferation, at least 20 adenines were required for the optimal genome replication and the virus replication could be severely impaired when the poly (A) tail was curtailed to 10 adenines. In addition to facilitating viral genome replication, the presence of 3′ UTR and poly(A) tail significantly enhance IRES-mediated translation efficiency. Furthermore, 3′ UTR or poly(A) tail could function as an individual element to enhance the DHAV-1 IRES-mediated translation, during which process, the 3′ UTR exerts a greater initiation efficiency than the poly(A)25 tail.
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Affiliation(s)
- Jun-Hao Chen
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Rui-Hua Zhang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Shao-Li Lin
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Peng-Fei Li
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Jing-Jing Lan
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Sha-Sha Song
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Ji-Ming Gao
- Department of Basic Medical Sciences, Taishan Medical College, Tai'an, China
| | - Yu Wang
- Department of Basic Medical Sciences, Taishan Medical College, Tai'an, China
| | - Zhi-Jing Xie
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
| | - Fu-Chang Li
- College of Animal Science and Technology, Shandong Agricultural University, Tai'an, China
| | - Shi-Jin Jiang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, China
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21
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Masuda T, Sunaga F, Naoi Y, Ito M, Takagi H, Katayama Y, Omatsu T, Oba M, Sakaguchi S, Furuya T, Yamasato H, Shirai J, Makino S, Mizutani T, Nagai M. Whole genome analysis of a novel picornavirus related to the Enterovirus/Sapelovirus supergroup from porcine feces in Japan. Virus Res 2018; 257:68-73. [PMID: 30227146 DOI: 10.1016/j.virusres.2018.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
A novel virus related to the Enterovirus/Sapelovirus supergroup in the family Picornaviridae was identified in healthy porcine feces in Japan by using a metagenomics approach. The genome of the virus, named Sapelo-like porcine picornavirus Japan (SPPVJ) Pig/Isi-Im1/JPN/2016, had a type-IV internal ribosomal entry site and carried a 6978-nucleotide-long single open reading frame encoding a 2326 amino acids (aa) polyprotein precursor. The coding sequence region consisted of leader protein (68 aa), a structural protein region P1 (824 aa), and the non-structural protein regions P2 (672 aa) and P3 (762 aa). Among representative picornaviruses, the P1, 2C, and 3CD regions of SPPVJ had the highest aa identities of 64.4%, 61.9%, and 73.3%, respectively, with the corresponding regions of sapelo-like bat picornavirus BtVs-PicoV/SC2013. Sequencing analysis of the RT-PCR products derived from the 5' untranslated and 3D regions revealed the presence of SPPVJ in 17.8% (19/107) of the feces from healthy and diarrheal pigs in 12 farms in 2015-2016. Further studies are needed to determine the origin and pathogenic potential of SPPJV in pigs and other mammals.
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Affiliation(s)
- Tsuneyuki Masuda
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori, 683-0017, Japan
| | - Fujiko Sunaga
- Laboratory of Infectious Diseases, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan
| | - Yuki Naoi
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Mika Ito
- Ishikawa Nanbu Livestock Hygiene Service Center, Kanazawa, Ishikawa, 920-3101, Japan
| | - Hiroki Takagi
- Department of Bioproduction Science, Ishikawa Prefectural University, Nonoichi, Ishikawa, 921-8836, Japan
| | - Yukie Katayama
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Tsutomu Omatsu
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Mami Oba
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Shoichi Sakaguchi
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Tetsuya Furuya
- Laboratory of Veterinary Microbiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Hiroshi Yamasato
- Kurayoshi Livestock Hygiene Service Center, Kurayoshi, Tottori, 683-0017, Japan
| | - Junsuke Shirai
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Shinji Makino
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX, 77555-1019, USA
| | - Tetsuya Mizutani
- Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Makoto Nagai
- Laboratory of Infectious Diseases, Azabu University, Sagamihara, Kanagawa, 252-5201, Japan; Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan; Department of Bioproduction Science, Ishikawa Prefectural University, Nonoichi, Ishikawa, 921-8836, Japan.
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22
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Abstract
Codon usage depends on mutation bias, tRNA-mediated selection, and the need for high efficiency and accuracy in translation. One codon in a synonymous codon family is often strongly over-used, especially in highly expressed genes, which often leads to a high dN/dS ratio because dS is very small. Many different codon usage indices have been proposed to measure codon usage and codon adaptation. Sense codon could be misread by release factors and stop codons misread by tRNAs, which also contribute to codon usage in rare cases. This chapter outlines the conceptual framework on codon evolution, illustrates codon-specific and gene-specific codon usage indices, and presents their applications. A new index for codon adaptation that accounts for background mutation bias (Index of Translation Elongation) is presented and contrasted with codon adaptation index (CAI) which does not consider background mutation bias. They are used to re-analyze data from a recent paper claiming that translation elongation efficiency matters little in protein production. The reanalysis disproves the claim.
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23
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Zhu Q, Tan P, Li Y, Lin M, Li C, Mao J, Cui J, Zhao W, Wang HY, Wang RF. DHX29 functions as an RNA co-sensor for MDA5-mediated EMCV-specific antiviral immunity. PLoS Pathog 2018; 14:e1006886. [PMID: 29462185 PMCID: PMC5834211 DOI: 10.1371/journal.ppat.1006886] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/02/2018] [Accepted: 01/18/2018] [Indexed: 12/13/2022] Open
Abstract
Melanoma differentiation-associated gene-5 (MDA5) recognizes distinct subsets of viruses including Encephalomyocarditis virus (EMCV) of picornavirus family, but the molecular mechanisms underlying the specificity of the viral recognition of MDA5 in immune cells remain obscure. DHX29 is an RNA helicase required for the translation of 5’ structured mRNA of host and many picornaviruses (such as EMCV). We identify that DXH29 as a key RNA co-sensor, plays a significant role for specific recognition and triggering anti-EMCV immunity. We have observed that DHX29 regulates MDA5-, but not RIG-I-, mediated type I interferon signaling by preferentially interacting with structured RNAs and specifically with MDA5 for enhancing MDA5-dsRNA binding affinity. Overall, our results identify a critical role for DHX29 in innate immune response and provide molecular insights into the mechanisms by which DHX29 recognizes 5’ structured EMCV RNA and interacts with MDA5 for potent type I interferon signaling and antiviral immunity. Cytosolic sensor melanoma differentiation-associated gene-5 (MDA5) specifically detects long-duplex RNAs in the genome of double-stranded (ds)RNA viruses such as Encephalomyocarditis virus (EMCV) whereas retinoic acid-inducible gene-I (RIG-I) preferentially recognizes vesicular stomatitis virus (VSV) to trigger signaling cascades that lead to production of interferons and cytokines. However, weak RNA binding capacity of MDA5 significantly attenuates the antiviral response. Here, we reveal that DHX29 as a co-sensor of MDA5 ensures the specific and efficient MDA5-RNA interactions leading to a complete MDA5-mediated antiviral signaling. Depletion of DHX29 substantially reduces the activity of MDA5 whereas activity of RIG-I remains intact. These findings provide a mechanism for DHX29 coactivation of MDA5 and a biological context for MDA5-RNA filaments in antiviral response.
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Affiliation(s)
- Qingyuan Zhu
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
| | - Peng Tan
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, United States of America
| | - Yinyin Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
| | - Meng Lin
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Chaoran Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
- Xiangya Hospital, Central South University, Changsha, China
| | - Jingrong Mao
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
- Xiangya Hospital, Central South University, Changsha, China
| | - Jun Cui
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wei Zhao
- Key Laboratory for Stem Cells and Tissue Engineering of the Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Helen Y. Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
| | - Rong-Fu Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX, United States of America
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, United States of America
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, New York, NY, United States of America
- * E-mail:
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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: 87] [Impact Index Per Article: 14.5] [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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Abstract
Bioinformatic analysis can not only accelerate drug target identification and drug candidate screening and refinement, but also facilitate characterization of side effects and predict drug resistance. High-throughput data such as genomic, epigenetic, genome architecture, cistromic, transcriptomic, proteomic, and ribosome profiling data have all made significant contribution to mechanismbased drug discovery and drug repurposing. Accumulation of protein and RNA structures, as well as development of homology modeling and protein structure simulation, coupled with large structure databases of small molecules and metabolites, paved the way for more realistic protein-ligand docking experiments and more informative virtual screening. I present the conceptual framework that drives the collection of these high-throughput data, summarize the utility and potential of mining these data in drug discovery, outline a few inherent limitations in data and software mining these data, point out news ways to refine analysis of these diverse types of data, and highlight commonly used software and databases relevant to drug discovery.
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Affiliation(s)
- Xuhua Xia
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Ottawa Institute of Systems Biology, Ottawa K1H 8M5, Canada
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Asnani M, Pestova TV, Hellen CUT. PCBP2 enables the cadicivirus IRES to exploit the function of a conserved GRNA tetraloop to enhance ribosomal initiation complex formation. Nucleic Acids Res 2016; 44:9902-9917. [PMID: 27387282 PMCID: PMC5175331 DOI: 10.1093/nar/gkw609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
The cadicivirus IRES diverges structurally from canonical Type 1 IRESs (e.g. poliovirus) but nevertheless also contains an essential GNRA tetraloop in a subdomain (d10c) that is homologous to poliovirus dIVc. In addition to canonical initiation factors, the canonical Type 1 and divergent cadicivirus IRESs require the same IRES trans-acting factor, poly(C)-binding protein 2 (PCBP2). PCBP2 has three KH domains and binds poliovirus IRES domain dIV in the vicinity of the tetraloop. How PCBP2 binds the cadicivirus IRES, and the roles of PCBP2 and the tetraloop in Type 1 IRES function are unknown. Here, directed hydroxyl radical probing showed that KH1 also binds near the cadicivirus tetraloop. KH2 and KH3 bind adjacently to an IRES subdomain (d10b) that is unrelated to dIV, with KH3 in an inverted orientation. KH3 is critical for PCBP2's binding to this IRES whereas KH1 is essential for PCBP2's function in promoting initiation. PCBP2 enforced the wild-type structure of d10c when it contained minor destabilizing substitutions, exposing the tetraloop. Strikingly, PCBP2 enhanced initiation on mutant IRESs that retained consensus GNRA tetraloops, whereas mutants with divergent sequences did not respond to PCBP2. These studies show that PCBP2 enables the IRES to exploit the GNRA tetraloop to enhance initiation.
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Affiliation(s)
- Mukta Asnani
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA
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Simonetti A, Brito Querido J, Myasnikov AG, Mancera-Martinez E, Renaud A, Kuhn L, Hashem Y. eIF3 Peripheral Subunits Rearrangement after mRNA Binding and Start-Codon Recognition. Mol Cell 2016; 63:206-217. [PMID: 27373335 DOI: 10.1016/j.molcel.2016.05.033] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/07/2016] [Accepted: 05/23/2016] [Indexed: 11/30/2022]
Abstract
mRNA translation initiation in eukaryotes requires the cooperation of a dozen eukaryotic initiation factors (eIFs) forming several complexes, which leads to mRNA attachment to the small ribosomal 40S subunit, mRNA scanning for start codon, and accommodation of initiator tRNA at the 40S P site. eIF3, composed of 13 subunits, 8 core (a, c, e, f, h, l, k, and m) and 5 peripheral (b, d, g, i, and j), plays a central role during this process. Here we report a cryo-electron microscopy structure of a mammalian 48S initiation complex at 5.8 Å resolution. It shows the relocation of subunits eIF3i and eIF3g to the 40S intersubunit face on the GTPase binding site, at a late stage in initiation. On the basis of a previous study, we demonstrate the relocation of eIF3b to the 40S intersubunit face, binding below the eIF2-Met-tRNAi(Met) ternary complex upon mRNA attachment. Our analysis reveals the deep rearrangement of eIF3 and unravels the molecular mechanism underlying eIF3 function in mRNA scanning and timing of ribosomal subunit joining.
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Affiliation(s)
- Angelita Simonetti
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France.
| | - Jailson Brito Querido
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France
| | | | - Eder Mancera-Martinez
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France
| | - Adeline Renaud
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France
| | - Lauriane Kuhn
- CNRS, Proteomic Platform Strasbourg - Esplanade, 67084 Strasbourg, France
| | - Yaser Hashem
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France.
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Asnani M, Pestova TV, Hellen CUT. Initiation on the divergent Type I cadicivirus IRES: factor requirements and interactions with the translation apparatus. Nucleic Acids Res 2016; 44:3390-407. [PMID: 26873921 PMCID: PMC4838371 DOI: 10.1093/nar/gkw074] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/29/2016] [Indexed: 01/03/2023] Open
Abstract
Cadicivirus (CDV) is unique amongst picornaviruses in having a dicistronic genome with internal ribosomal entry sites (IRESs) preceding both open reading frames. Here, we investigated initiation on the 5'-terminal IRES. We report that the 982-nt long 5'UTR comprises 12 domains (d1-d12), five of which (d8-d12, nts 341-950) constitute a divergent Type I IRES. It comprises central elements (the apex of d10, d11 and the following polypyrimidine tract) that are homologous to corresponding elements in canonical Type 1 IRESs, and non-canonical flanking domains (d8, d9 and d12). In vitro reconstitution revealed that as with canonical Type I IRESs, 48S complex formation requires eukaryotic initiation factors (eIFs) 1, 1A, 2, 3, 4A, 4B and 4G, and the poly(C) binding protein 2 (PCBP2), and starts with specific binding of eIF4G/eIF4A to d11. However, in contrast to canonical Type I IRESs, subsequent recruitment of 43S ribosomal complexes does not require direct interaction of their eIF3 constituent with the IRES-bound eIF4G. On the other hand, the CDV IRES forms a 40S/eIF3/IRES ternary complex, with multiple points of contact. These additional interactions with translational components could potentially stimulate recruitment of the 43S complex and alleviate the necessity for direct eIF4G/eIF3 interaction.
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Affiliation(s)
- Mukta Asnani
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC44, Brooklyn, NY 11203, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC44, Brooklyn, NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, MSC44, Brooklyn, NY 11203, USA
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29
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Abaeva IS, Pestova TV, Hellen CUT. Attachment of ribosomal complexes and retrograde scanning during initiation on the Halastavi árva virus IRES. Nucleic Acids Res 2016; 44:2362-77. [PMID: 26783202 PMCID: PMC4797288 DOI: 10.1093/nar/gkw016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/07/2016] [Indexed: 01/02/2023] Open
Abstract
Halastavi árva virus (HalV) has a positive-sense RNA genome, with an 827 nt-long 5' UTR and an intergenic region separating two open reading frames. Whereas the encoded proteins are most homologous to Dicistrovirus polyproteins, its 5' UTR is distinct. Here, we report that the HalV 5' UTR comprises small stem-loop domains separated by long single-stranded areas and a large A-rich unstructured region surrounding the initiation codon AUG828, and possesses cross-kingdom internal ribosome entry site (IRES) activity. In contrast to most viral IRESs, it does not depend on structural integrity and specific interaction of a structured element with a translational component, and is instead determined by the unstructured region flanking AUG828. eIF2, eIF3, eIF1 and eIF1A promote efficient 48S initiation complex formation at AUG828, which is reduced ∼5-fold on omission of eIF1 and eIF1A. Initiation involves direct attachment of 43S preinitiation complexes within a short window at or immediately downstream of AUG828. 40S and eIF3 are sufficient for initial binding. After attachment, 43S complexes undergo retrograde scanning, strongly dependent on eIF1 and eIF1A. eIF4A/eIF4G stimulated initiation only at low temperatures or on mutants, in which areas surrounding AUG828 had been replaced by heterologous sequences. However, they strongly promoted initiation at AUG872, yielding a proline-rich oligopeptide.
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Affiliation(s)
- Irina S Abaeva
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, 11203, NY, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, 11203, NY, USA
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30
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Rai DK, Lawrence P, Kloc A, Schafer E, Rieder E. Analysis of the interaction between host factor Sam68 and viral elements during foot-and-mouth disease virus infections. Virol J 2015; 12:224. [PMID: 26695943 PMCID: PMC4689063 DOI: 10.1186/s12985-015-0452-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/10/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The nuclear protein Src-associated protein of 68 kDa in mitosis (Sam68) is known to bind RNA and be involved in cellular processes triggered in response to environmental stresses, including virus infection. Interestingly, Sam68 is a multi-functional protein implicated in the life cycle of retroviruses and picornaviruses and is also considered a marker of virus-induced stress granules (SGs). Recently, we demonstrated the partial redistribution of Sam68 to the cytoplasm in FMDV infected cells, its interaction with viral protease 3C(pro), and found a significant reduction in viral titers as consequence of Sam68-specific siRNA knockdowns. Despite of that, details of how it benefits FMDV remains to be elucidated. METHODS Sam68 cytoplasmic localization was examined by immunofluorescent microscopy, counterstaining with antibodies against Sam68, a viral capsid protein and markers of SGs. The relevance of RAAA motifs in the IRES was investigated using electromobility shift assays with Sam68 protein and parental and mutant FMDV RNAs. In addition, full genome WT and mutant or G-luc replicon RNAs were tested following transfection in mammalian cells. The impact of Sam68 depletion to virus protein and RNA synthesis was investigated in a cell-free system. Lastly, through co-immunoprecipitation, structural modeling, and subcellular fractionation, viral protein interactions with Sam68 were explored. RESULTS FMDV-induced cytoplasmic redistribution of Sam68 resulted in it temporarily co-localizing with SG marker: TIA-1. Mutations that disrupted FMDV IRES RAAA motifs, with putative affinity to Sam68 in domain 3 and 4 cause a reduction on the formation of ribonucleoprotein complexes with this protein and resulted in non-viable progeny viruses and replication-impaired replicons. Furthermore, depletion of Sam68 in cell-free extracts greatly diminished FMDV RNA replication, which was restored by addition of recombinant Sam68. The results here demonstrated that Sam68 specifically co-precipitates with both FMDV 3D(pol) and 3C(pro) consistent with early observations of FMDV 3C(pro)-induced cleavage of Sam68. CONCLUSION We have found that Sam68 is a specific binding partner for FMDV non-structural proteins 3C(pro) and 3D(pol) and showed that mutations at RAAA motifs in IRES domains 3 and 4 cause a decrease in Sam68 affinity to these RNA elements and rendered the mutant RNA non-viable. Interestingly, in FMDV infected cells re-localized Sam68 was transiently detected along with SG markers in the cytoplasm. These results support the importance of Sam68 as a host factor co-opted by FMDV during infection and demonstrate that Sam68 interact with both, FMDV RNA motifs in the IRES and viral non-structural proteins 3C(pro) and 3D(pol).
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Affiliation(s)
- Devendra K Rai
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Paul Lawrence
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Anna Kloc
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Elizabeth Schafer
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Elizabeth Rieder
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
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Angulo J, Ulryck N, Deforges J, Chamond N, Lopez-Lastra M, Masquida B, Sargueil B. LOOP IIId of the HCV IRES is essential for the structural rearrangement of the 40S-HCV IRES complex. Nucleic Acids Res 2015; 44:1309-25. [PMID: 26626152 PMCID: PMC4756818 DOI: 10.1093/nar/gkv1325] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022] Open
Abstract
As obligatory intracellular parasites, viruses rely on cellular machines to complete their life cycle, and most importantly they recruit the host ribosomes to translate their mRNA. The Hepatitis C viral mRNA initiates translation by directly binding the 40S ribosomal subunit in such a way that the initiation codon is correctly positioned in the P site of the ribosome. Such a property is likely to be central for many viruses, therefore the description of host-pathogen interaction at the molecular level is instrumental to provide new therapeutic targets. In this study, we monitored the 40S ribosomal subunit and the viral RNA structural rearrangement induced upon the formation of the binary complex. We further took advantage of an IRES viral mutant mRNA deficient for translation to identify the interactions necessary to promote translation. Using a combination of structure probing in solution and molecular modeling we establish a whole atom model which appears to be very similar to the one obtained recently by cryoEM. Our model brings new information on the complex, and most importantly reveals some structural rearrangement within the ribosome. This study suggests that the formation of a ‘kissing complex’ between the viral RNA and the 18S ribosomal RNA locks the 40S ribosomal subunit in a conformation proficient for translation.
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Affiliation(s)
- Jenniffer Angulo
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Nathalie Ulryck
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Jules Deforges
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Nathalie Chamond
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Marcelo Lopez-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Benoît Masquida
- UMR 7156 Génétique Moléculaire Génomique Microbiologie, CNRS - Université de Strasbourg, Strasbourg, France
| | - Bruno Sargueil
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologiques, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
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32
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Liu X, Oka T, Wang Q. Genomic characterization of a US porcine kobuvirus strain. Arch Microbiol 2015; 197:1033-40. [PMID: 26316163 DOI: 10.1007/s00203-015-1139-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/22/2015] [Accepted: 08/02/2015] [Indexed: 12/14/2022]
Abstract
Porcine kobuvirus has been detected from pig fecal samples in the USA, but there is still no information on the full-length genomes. In this study, we characterized the first complete genomic sequence of a US porcine kobuvirus strain OH/RV50/2011. The viral genome is 8123 nucleotides (nt) long, including a 576-nt 5'-untranslated region (UTR), a 7380-nt polyprotein encoding sequence, and a 167-nt 3'-UTR. A complete genome sequence alignment suggested that two types of porcine kobuviruses were found based on whether a 30-aa deletion existed in the 2B encoding region. Furthermore, several conserved motifs that can be used for the design of universal kobuvirus or porcine kobuvirus-specific primers were verified in non-structural protein genes. Phylogenetic analysis based on the complete genome sequence showed that RV50 was grouped with other porcine kobuviruses and more closely related to Chinese strains. Secondary structure analysis of the 5'-UTR showed that RV50 has three stem-loop domains in the first 108 nt and has a potential hepacivirus-/pestivirus-like type IV group-B-like internal ribosomal entry site, like the porcine kobuvirus prototype strain S-1. Codon usage analysis showed that the most preferred usage tends to be C or U at the end of a codon in a porcine kobuvirus genome. These results will be useful in understanding the evolution of porcine kobuviruses .
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Affiliation(s)
- Xinsheng Liu
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, College of Food, Agricultural and Environmental Sciences, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, USA,
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Song QQ, Lu MZ, Song J, Chi MM, Sheng LJ, Yu J, Luo XN, Zhang L, Yao HL, Han J. Coxsackievirus B3 2A protease promotes encephalomyocarditis virus replication. Virus Res 2015; 208:22-9. [PMID: 26052084 DOI: 10.1016/j.virusres.2015.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/23/2015] [Accepted: 05/25/2015] [Indexed: 01/12/2023]
Abstract
To determine whether 2A protease of the enterovirus genus with type I internal ribosome entry site (IRES) effect on the viral replication of type II IRES, coxsackievirus B3(CVB3)-encoded protease 2A and encephalomyocarditis virus (EMCV) IRES (Type II)-dependent or cap-dependent report gene were transiently co-expressed in eukaryotic cells. We found that CVB3 2A protease not only inhibited translation of cap-dependent reporter genes through the cleavage of eIF4GI, but also conferred high EMCV IRES-dependent translation ability and promoted EMCV replication. Moreover, deletions of short motif (aa13-18 RVVNRH, aa65-70 KNKHYP, or aa88-93 PRRYQSH) resembling the nuclear localization signals (NLS) or COOH-terminal acidic amino acid motif (aa133-147 DIRDLLWLEDDAMEQ) of CVB3 2A protease decreased both its EMCV IRES-dependent translation efficiency and destroy its cleavage on eukaryotic initiation factor 4G (eIF4G) I. Our results may provide better understanding into more effective interventions and treatments for co-infection of viral diseases.
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Affiliation(s)
- Qin-Qin Song
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Ming-Zhi Lu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Juan Song
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Miao-Miao Chi
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Lin-Jun Sheng
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Jie Yu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Xiao-Nuan Luo
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Lu Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China
| | - Hai-Lan Yao
- Molecular Immunology Laboratory, Capital Institute of Pediatrics, 2 YaBao Rd, Beijing 100020, China
| | - Jun Han
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Hangzhou), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Beijing 102206, China.
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Lozano G, Martínez-Salas E. Structural insights into viral IRES-dependent translation mechanisms. Curr Opin Virol 2015; 12:113-20. [PMID: 26004307 DOI: 10.1016/j.coviro.2015.04.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 01/10/2023]
Abstract
A diverse group of viruses subvert the host translational machinery to promote viral genome translation. This process often involves altering canonical translation initiation factors to repress cellular protein synthesis while viral proteins are efficiently synthesized. The discovery of this strategy in picornaviruses, which is based on the use of internal ribosome entry site (IRES) elements, opened new avenues to study alternative translational control mechanisms evolved in different groups of RNA viruses. IRESs are cis-acting RNA sequences that adopt three-dimensional structures and recruit the translation machinery assisted by a subset of translation initiation factors and various RNA binding proteins. However, IRESs present in the genome of different RNA viruses perform the same function despite lacking conservation of primary sequence and secondary RNA structure, and differing in host factor requirement to recruit the translation machinery. Evolutionary conserved motifs tend to preserve sequences impacting on RNA structure and RNA-protein interactions important for IRES function. While some motifs are found in various picornavirus IRESs, others occur only in one type reflecting specialized factor requirements. This review is focused to describe recent advances on the principles and RNA structure features of picornavirus IRESs.
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Affiliation(s)
- Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Encarnación Martínez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain.
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Lloyd RE. Nuclear proteins hijacked by mammalian cytoplasmic plus strand RNA viruses. Virology 2015; 479-480:457-74. [PMID: 25818028 PMCID: PMC4426963 DOI: 10.1016/j.virol.2015.03.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/12/2015] [Accepted: 03/03/2015] [Indexed: 01/18/2023]
Abstract
Plus strand RNA viruses that replicate in the cytoplasm face challenges in supporting the numerous biosynthetic functions required for replication and propagation. Most of these viruses are genetically simple and rely heavily on co-opting cellular proteins, particularly cellular RNA-binding proteins, into new roles for support of virus infection at the level of virus-specific translation, and building RNA replication complexes. In the course of infectious cycles many nuclear-cytoplasmic shuttling proteins of mostly nuclear distribution are detained in the cytoplasm by viruses and re-purposed for their own gain. Many mammalian viruses hijack a common group of the same factors. This review summarizes recent gains in our knowledge of how cytoplasmic RNA viruses use these co-opted host nuclear factors in new functional roles supporting virus translation and virus RNA replication and common themes employed between different virus groups. Nuclear shuttling host proteins are commonly hijacked by RNA viruses to support replication. A limited group of ubiquitous RNA binding proteins are commonly hijacked by a broad range of viruses. Key virus proteins alter roles of RNA binding proteins in different stages of virus replication.
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Affiliation(s)
- Richard E Lloyd
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, United States.
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Asnani M, Kumar P, Hellen CUT. Widespread distribution and structural diversity of Type IV IRESs in members of Picornaviridae. Virology 2015; 478:61-74. [PMID: 25726971 DOI: 10.1016/j.virol.2015.02.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 01/13/2023]
Abstract
Picornavirus genomes contain internal ribosomal entry sites (IRESs) that promote end-independent translation initiation. Five structural classes of picornavirus IRES have been identified, but numerous IRESs remain unclassified. Here, previously unrecognized Type IV IRESs were identified in members of three proposed picornavirus genera (Limnipivirus, Pasivirus, Rafivirus) and four recognized genera (Kobuvirus, Megrivirus, Sapelovirus, Parechovirus). These IRESs are ~230-420 nucleotides long, reflecting heterogeneity outside a common structural core. Closer analysis yielded insights into evolutionary processes that have shaped contemporary IRESs. The presence of related IRESs in diverse genera supports the hypothesis that they are heritable genetic elements that spread by horizontal gene transfer. Recombination likely also accounts for the exchange of some peripheral subdomains, suggesting that IRES evolution involves incremental addition of elements to a pre-existing core. Nucleotide conservation is concentrated in ribosome-binding sites, and at the junction of helical domains, likely to ensure orientation of subdomains in an active conformation.
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Affiliation(s)
- Mukta Asnani
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Parimal Kumar
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Christopher U T Hellen
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
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37
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Olarte-Castillo XA, Heeger F, Mazzoni CJ, Greenwood AD, Fyumagwa R, Moehlman PD, Hofer H, East ML. Molecular characterization of canine kobuvirus in wild carnivores and the domestic dog in Africa. Virology 2015; 477:89-97. [PMID: 25667111 DOI: 10.1016/j.virol.2015.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/23/2014] [Accepted: 01/09/2015] [Indexed: 11/29/2022]
Abstract
Knowledge of Kobuvirus (Family Picornaviridae) infection in carnivores is limited and has not been described in domestic or wild carnivores in Africa. To fill this gap in knowledge we used RT-PCR to screen fresh feces from several African carnivores. We detected kobuvirus RNA in samples from domestic dog, golden jackal, side-striped jackal and spotted hyena. Using next generation sequencing we obtained one complete Kobuvirus genome sequence from each of these species. Our phylogenetic analyses revealed canine kobuvirus (CaKV) infection in all four species and placed CaKVs from Africa together and separately from CaKVs from elsewhere. Wild carnivore strains were more closely related to each other than to those from domestic dogs. We found that the secondary structure model of the IRES was similar to the Aichivirus-like IRES subclass and was conserved among African strains. We describe the first CaKVs from Africa and extend the known host range of CaKV.
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Affiliation(s)
- Ximena A Olarte-Castillo
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany
| | - Felix Heeger
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany; Berlin Center for Genomics in Biodiversity Research, Königin-Luise-Straße 6-8, 14195 Berlin, Germany
| | - Camila J Mazzoni
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany; Berlin Center for Genomics in Biodiversity Research, Königin-Luise-Straße 6-8, 14195 Berlin, Germany
| | - Alex D Greenwood
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany
| | - Robert Fyumagwa
- Tanzania Wildlife Research Institute, P.O. Box 661, Arusha, Tanzania
| | | | - Heribert Hofer
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany
| | - Marion L East
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315 Berlin, Germany.
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Martínez-Salas E, Francisco-Velilla R, Fernandez-Chamorro J, Lozano G, Diaz-Toledano R. Picornavirus IRES elements: RNA structure and host protein interactions. Virus Res 2015; 206:62-73. [PMID: 25617758 DOI: 10.1016/j.virusres.2015.01.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/05/2015] [Accepted: 01/12/2015] [Indexed: 01/26/2023]
Abstract
Internal ribosome entry site (IRES) elements were discovered in picornaviruses. These elements are cis-acting RNA sequences that adopt diverse three-dimensional structures and recruit the translation machinery using a 5' end-independent mechanism assisted by a subset of translation initiation factors and various RNA binding proteins termed IRES transacting factors (ITAFs). Many of these factors suffer important modifications during infection including cleavage by picornavirus proteases, changes in the phosphorylation level and/or redistribution of the protein from the nuclear to the cytoplasm compartment. Picornavirus IRES are amongst the most potent elements described so far. However, given their large diversity and complexity, the mechanistic basis of its mode of action is not yet fully understood. This review is focused to describe recent advances on the studies of RNA structure and RNA-protein interactions modulating picornavirus IRES activity.
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Affiliation(s)
- Encarnación Martínez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain.
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Gloria Lozano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Rosa Diaz-Toledano
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid, Nicolas Cabrera 1, 28049 Madrid, Spain
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39
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Deforges J, Locker N, Sargueil B. mRNAs that specifically interact with eukaryotic ribosomal subunits. Biochimie 2014; 114:48-57. [PMID: 25530261 DOI: 10.1016/j.biochi.2014.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/11/2014] [Indexed: 12/25/2022]
Abstract
The accuracy of start codon selection is determined by the translation initiation process. In prokaryotes the initiation step on most mRNAs relies on recruitment of the small ribosomal subunit onto the initiation codon by base pairing between the mRNA and the 16S rRNA. Eukaryotes have evolved a complex molecular machinery involving at least 11 initiation factors, and mRNAs do not directly recruit the small ribosomal subunit. Instead the initiation complex is recruited to the 5' end of the mRNA through a complex protein network including eIF4E that interacts with the 5' cap structure and poly-A binding protein that interacts with the 3'end. However, some viral and cellular mRNAs are able to escape this pathway by internal recruitment of one or several components of the translation machinery. Here we review those eukaryotic mRNAs that have been reported to directly recruit the 40S ribosomal subunit internally. In the well characterized cases of viral IRESes, a specific RNA structure is involved in this process, and in addition to recruitment of the ribosome, the mRNA also manipulates the ribosome structure to stimulate the first translocation step. We also review recently described IRES/ribosome interactions in cases where the molecular mechanism leading to translation initiation has yet to be described. Finally we evaluate the possibility that mRNA may recruit the 40S ribosomal subunit through base pairing with the 18S rRNA.
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Affiliation(s)
- Jules Deforges
- CNRS UMR8015, laboratoire de cristallographie et RMN biologiques, France; Université Paris Descartes, 4 avenue de l'observatoire, Paris Cedex 06, 75270, France
| | - Nicolas Locker
- University of Surrey, Faculty of Health and Medical Sciences, School of Biosciences and Medicine, Guildford, United Kingdom
| | - Bruno Sargueil
- CNRS UMR8015, laboratoire de cristallographie et RMN biologiques, France; Université Paris Descartes, 4 avenue de l'observatoire, Paris Cedex 06, 75270, France.
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40
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Pankovics P, Boros Á, Kiss T, Reuter G. Identification and complete genome analysis of kobuvirus in faecal samples of European roller (Coracias garrulus): for the first time in a bird. Arch Virol 2014; 160:345-51. [PMID: 25195063 DOI: 10.1007/s00705-014-2228-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 08/31/2014] [Indexed: 12/11/2022]
Abstract
The genus Kobuvirus (Picornaviridae) consists of three species, Aichivirus A (e.g., Aichi virus, which infects humans), Aichivirus B and Aichivirus C. Kobuvirus have not been detected in non-mammal species including birds. In this study, a novel kobuvirus was identified in 3 (17 %) out of 18 faecal samples collected from European rollers (Coracias garrulus) in Hungary. The complete genome sequence of strain SZAL6-KoV/2011/HUN (KJ934637), which was determined using a novel 5'/3' RACE method (dsRNA-RACE) involving a double-stranded (ds)RNA intermediate, has a type-V IRES at the 5' end and a cis-acting element (CRE) in the 3C gene and encodes L and 2A(H-box/NC) proteins, but it does not contain the sequence forming a "barbell-like" secondary RNA structure in the 3'UTR. SZAL6-KoV/2011/HUN has 72 %, 73 %, and 81 % amino acid sequence identity to the P1, P2, and P3 protein, respectively, of Aichi virus. Evolutionary analysis showed that SZAL6-KoV/2011/HUN shares a common ancestor with other kobuviruses but belongs to a more ancient lineage in the species Aichivirus A. Investigation of the known kobuviruses in different animals and discovery of novel kobuviruses in potential host species helps to clarify the evolutionary connection and zoonotic potential of kobuviruses.
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Affiliation(s)
- Péter Pankovics
- Regional Laboratory of Virology, National Reference Laboratory of Gastroenteric Viruses, ÁNTSZ Regional Institute of State Public Health Service, Szabadság út 7, 7623, Pécs, Hungary
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41
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Chamond N, Deforges J, Ulryck N, Sargueil B. 40S recruitment in the absence of eIF4G/4A by EMCV IRES refines the model for translation initiation on the archetype of Type II IRESs. Nucleic Acids Res 2014; 42:10373-84. [PMID: 25159618 PMCID: PMC4176346 DOI: 10.1093/nar/gku720] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Initiation of translation on Type II IRESs, such as those of EMCV and FMDV viruses, has been well documented in the recent years. For EMCV, the current model argues for a mechanism in which the key interaction necessary for the pre-initiation complex recruitment is eIF4G binding to the central J-K domains of EMCV-IRES. Here we demonstrate that, in contrast with the current model, the molecular mechanism of EMCV-IRES involves direct recruitment of the 40S subunit. Importantly, we identified a specific structural element that prevents the correct positioning of the initiation codon in the close vicinity of the ribosomal P site. This work clarifies how this interaction could not be anticipated by earlier studies and allows us to propose a new model for initiation complex assembly on EMCV-IRES. The role attributed to eIF4G/4A can thus be refined as stabilizing/promoting the conformational changes that are necessary for IRES function, thus resembling the role conventionally assigned to ITAFs. This raises the interesting possibility that IRESs are primarily ribosome binders, some of which having partly lost the ability to fold into the active structure without the help of proteins.
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Affiliation(s)
- Nathalie Chamond
- CNRS UMR8015, Université Paris Descartes, Paris Cedex 06, 75270, France
| | - Jules Deforges
- CNRS UMR8015, Université Paris Descartes, Paris Cedex 06, 75270, France
| | - Nathalie Ulryck
- CNRS UMR8015, Université Paris Descartes, Paris Cedex 06, 75270, France
| | - Bruno Sargueil
- CNRS UMR8015, Université Paris Descartes, Paris Cedex 06, 75270, France
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42
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Au HHT, Jan E. Novel viral translation strategies. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:779-801. [PMID: 25045163 PMCID: PMC7169809 DOI: 10.1002/wrna.1246] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/03/2014] [Accepted: 05/08/2014] [Indexed: 01/06/2023]
Abstract
Viral genomes are compact and encode a limited number of proteins. Because they do not encode components of the translational machinery, viruses exhibit an absolute dependence on the host ribosome and factors for viral messenger RNA (mRNA) translation. In order to recruit the host ribosome, viruses have evolved unique strategies to either outcompete cellular transcripts that are efficiently translated by the canonical translation pathway or to reroute translation factors and ribosomes to the viral genome. Furthermore, viruses must evade host antiviral responses and escape immune surveillance. This review focuses on some recent major findings that have revealed unconventional strategies that viruses utilize, which include usurping the host translational machinery, modulating canonical translation initiation factors to specifically enhance or repress overall translation for the purpose of viral production, and increasing viral coding capacity. The discovery of these diverse viral strategies has provided insights into additional translational control mechanisms and into the viral host interactions that ensure viral protein synthesis and replication. WIREs RNA 2014, 5:779–801. doi: 10.1002/wrna.1246 This article is categorized under:
Translation > Translation Mechanisms Translation > Translation Regulation
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Affiliation(s)
- Hilda H T Au
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
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43
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Souii A, Ben M'hadheb-Gharbi M, Gharbi J. Role of RNA structure motifs in IRES-dependent translation initiation of the coxsackievirus B3: new insights for developing live-attenuated strains for vaccines and gene therapy. Mol Biotechnol 2014; 55:179-202. [PMID: 23881360 DOI: 10.1007/s12033-013-9674-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Internal ribosome entry site (IRES) elements are highly structured RNA sequences that function to recruit ribosomes for the initiation of translation. In contrast to the canonical cap-binding, the mechanism of IRES-mediated translation initiation is still poorly understood. Translation initiation of the coxsackievirus B3 (CVB3), a causative agent of viral myocarditis, has been shown to be mediated by a highly ordered structure of the 5' untranslated region (5'UTR), which harbors an IRES. Taking into account that efficient initiation of mRNA translation depends on temporally and spatially orchestrated sequence of RNA-protein and RNA-RNA interactions, and that, at present, little is known about these interactions, we aimed to describe recent advances in our understanding of molecular structures and biochemical functions of the translation initiation process. Thus, this review will explore the IRES elements as important RNA structures and the significance of these structures in providing an alternative mechanism of translation initiation of the CVB3 RNA. Since translation initiation is the first intracellular step during the CVB3 infection cycle, the IRES region provides an ideal target for antiviral therapies. Interestingly, the 5' and 3'UTRs represent promising candidates for the study of CVB3 cardiovirulence and provide new insights for developing live-attenuated vaccines.
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Affiliation(s)
- Amira Souii
- Institut Supérieur de Biotechnologie de Monastir-Université de Monastir, Avenue Tahar Hadded, BP 74, 5000, Monastir, Tunisia
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44
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Mickleburgh I, Kafasla P, Cherny D, Llorian M, Curry S, Jackson RJ, Smith CWJ. The organization of RNA contacts by PTB for regulation of FAS splicing. Nucleic Acids Res 2014; 42:8605-20. [PMID: 24957602 PMCID: PMC4117754 DOI: 10.1093/nar/gku519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Post-transcriptional steps of gene expression are regulated by RNA binding proteins. Major progress has been made in characterizing RNA-protein interactions, from high resolution structures to transcriptome-wide profiling. Due to the inherent technical challenges, less attention has been paid to the way in which proteins with multiple RNA binding domains engage with target RNAs. We have investigated how the four RNA recognition motif (RRM) domains of Polypyrimidine tract binding (PTB) protein, a major splicing regulator, interact with FAS pre-mRNA under conditions in which PTB represses FAS exon 6 splicing. A combination of tethered hydroxyl radical probing, targeted inactivation of individual RRMs and single molecule analyses revealed an unequal division of labour between the four RRMs of PTB. RNA binding by RRM4 is the most important for function despite the low intrinsic binding specificity and the complete lack of effect of disrupting individual RRM4 contact points on the RNA. The ordered RRM3-4 di-domain packing provides an extended binding surface for RNA interacting at RRM4, via basic residues in the preceding linker. Our results illustrate how multiple alternative low-specificity binding configurations of RRM4 are consistent with repressor function as long as the overall ribonucleoprotein architecture provided by appropriate di-domain packing is maintained.
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Affiliation(s)
- Ian Mickleburgh
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Panagiota Kafasla
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Dmitry Cherny
- Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Miriam Llorian
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Stephen Curry
- Division of Cell and Molecular Biology, Imperial College, Exhibition Road, London SW7 2AZ, UK
| | - Richard J Jackson
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Christopher W J Smith
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
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45
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Sweeney TR, Abaeva IS, Pestova TV, Hellen CUT. The mechanism of translation initiation on Type 1 picornavirus IRESs. EMBO J 2013; 33:76-92. [PMID: 24357634 DOI: 10.1002/embj.201386124] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Picornavirus Type 1 IRESs comprise five principal domains (dII-dVI). Whereas dV binds eIF4G, a conserved AUG in dVI was suggested to stimulate attachment of 43S ribosomal preinitiation complexes, which then scan to the initiation codon. Initiation on Type 1 IRESs also requires IRES trans-acting factors (ITAFs), and several candidates have been proposed. Here, we report the in vitro reconstitution of initiation on three Type 1 IRESs: poliovirus (PV), enterovirus 71 (EV71), and bovine enterovirus (BEV). All of them require eIF2, eIF3, eIF4A, eIF4G, eIF4B, eIF1A, and a single ITAF, poly(C) binding protein 2 (PCBP2). In each instance, initiation starts with binding of eIF4G/eIF4A. Subsequent recruitment of 43S complexes strictly requires direct interaction of their eIF3 constituent with eIF4G. The following events can differ between IRESs, depending on the stability of dVI. If it is unstructured (BEV), all ribosomes scan through dVI to the initiation codon, requiring eIF1 to bypass its AUG. If it is structured (PV, EV71), most initiation events occur without inspection of dVI, implying that its AUG does not determine ribosomal attachment.
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Affiliation(s)
- Trevor R Sweeney
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY, USA
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46
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Martínez-Salas E, Lozano G, Fernandez-Chamorro J, Francisco-Velilla R, Galan A, Diaz R. RNA-binding proteins impacting on internal initiation of translation. Int J Mol Sci 2013; 14:21705-26. [PMID: 24189219 PMCID: PMC3856030 DOI: 10.3390/ijms141121705] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/17/2013] [Accepted: 10/22/2013] [Indexed: 12/20/2022] Open
Abstract
RNA-binding proteins (RBPs) are pivotal regulators of all the steps of gene expression. RBPs govern gene regulation at the post-transcriptional level by virtue of their capacity to assemble ribonucleoprotein complexes on certain RNA structural elements, both in normal cells and in response to various environmental stresses. A rapid cellular response to stress conditions is triggered at the step of translation initiation. Two basic mechanisms govern translation initiation in eukaryotic mRNAs, the cap-dependent initiation mechanism that operates in most mRNAs, and the internal ribosome entry site (IRES)-dependent mechanism activated under conditions that compromise the general translation pathway. IRES elements are cis-acting RNA sequences that recruit the translation machinery using a cap-independent mechanism often assisted by a subset of translation initiation factors and various RBPs. IRES-dependent initiation appears to use different strategies to recruit the translation machinery depending on the RNA organization of the region and the network of RBPs interacting with the element. In this review we discuss recent advances in understanding the implications of RBPs on IRES-dependent translation initiation.
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Affiliation(s)
- Encarnación Martínez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain.
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47
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Identification and characterization of porcine kobuvirus variant isolated from suckling piglet in Gansu province, China. Viruses 2013; 5:2548-60. [PMID: 24145960 PMCID: PMC3814603 DOI: 10.3390/v5102548] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/11/2013] [Accepted: 10/15/2013] [Indexed: 01/28/2023] Open
Abstract
Kobuviruses comprise three species, the Aichivirus A, Aichivirus B, and Aichivirus C (porcine kobuvirus). Porcine kobuvirus is endemic to pig farms and is not restricted geographically but, rather, is distributed worldwide. The complete genomic sequences of four porcine kobuvirus strains isolated during a diarrhea outbreak in piglets in the Gansu province of China were determined. Two of these strains exhibited variations relative to the traditional strains. The potential 3C/3D cleavage sites of the variant strains were Q/C, which differed from the Q/S in the traditional porcine kobuvirus genome. A 90-nucleotide deletion in the 2B protein and a single nucleotide insertion in the 3′UTR were found in the variant strains. The VP1 regions of all four porcine kobuviruses in our study were highly variable (81%–86%). Ten common amino acid mutations were found specifically at certain positions within the VP1 region. Significant recombination sites were identified using SimPlot scans of whole genome sequences. Porcine kobuviruses were also detected in pig serum, indicating that the virus can escape the gastrointestinal tract and travel to the circulatory system. These findings suggest that mutations and recombination events may have contributed to the high level of genetic diversity of porcine kobuviruses and serve as a driving force in its evolution.
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Souii A, Gharbi J, Ben M'hadheb-Gharbi M. Impaired binding of standard initiation factors eIF3b, eIF4G and eIF4B to domain V of the live-attenuated coxsackievirus B3 Sabin3-like IRES--alternatives for 5'UTR-related cardiovirulence mechanisms. Diagn Pathol 2013; 8:161. [PMID: 24063684 PMCID: PMC3853319 DOI: 10.1186/1746-1596-8-161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/17/2013] [Indexed: 01/28/2023] Open
Abstract
Abstract Internal ribosome entry site (IRES) elements fold into highly organized conserved secondary and probably tertiary structures that guide the ribosome to an internal site of the RNA at the IRES 3′end. The composition of the cellular proteome is under the control of multiple processes, one of the most important being translation initiation. In each poliovirus Sabin vaccine strain, a single point mutation in the IRES secondary-structure domain V is a major determinant of neurovirulence and translation attenuation. Here we are extrapolating poliovirus findings to a genomic related virus named coxsackievirus B3 CVB3); a causative agent of viral myocarditis. We have previously reported that Sabin3-like mutation (U473 → C) introduced in the domain V sequence of the CVB3 IRES led to a defective mutant with a serious reduction in translation efficiency and ribosomal initiation complex assembly, besides an impaired RNA-protein binding pattern. With the aim to identify proteins interacting with both CVB3 wild-type and Sabin3-like domain V RNAs and to assess the effect of the Sabin3-like mutation on these potential interactions, we have used a proteomic approach. This procedure allowed the identification of three RNA-binding proteins interacting with the domain V: eIF4G (p220), eIF3b (p116) and eIF4B (p80). Moreover, we report that this single-nucleotide exchange impairs the interaction pattern and the binding affinity of these standard translation initiation factors within the IRES domain V of the mutant strain. Taken together, these data indicate how this decisive Sabin3-like mutation mediates viral translation attenuation; playing a key role in the understanding of the cardiovirulence attenuation within this construct. Hence, these data provide further evidence for the crucial role of RNA structure for the IRES activity, and reinforce the idea of a distribution of function between the different IRES structural domains. Virtual slide The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6160165131045880.
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Affiliation(s)
- Amira Souii
- Institut Supérieur de Biotechnologie de Monastir, Université de Monastir, Avenue Tahar Hadded, BP 74, Monastir 5000, Tunisia.
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Hashem Y, des Georges A, Dhote V, Langlois R, Liao HY, Grassucci RA, Hellen CUT, Pestova TV, Frank J. Structure of the mammalian ribosomal 43S preinitiation complex bound to the scanning factor DHX29. Cell 2013; 153:1108-19. [PMID: 23706745 DOI: 10.1016/j.cell.2013.04.036] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/06/2013] [Accepted: 04/05/2013] [Indexed: 01/19/2023]
Abstract
Eukaryotic translation initiation begins with assembly of a 43S preinitiation complex. First, methionylated initiator methionine transfer RNA (Met-tRNAi(Met)), eukaryotic initiation factor (eIF) 2, and guanosine triphosphate form a ternary complex (TC). The TC, eIF3, eIF1, and eIF1A cooperatively bind to the 40S subunit, yielding the 43S preinitiation complex, which is ready to attach to messenger RNA (mRNA) and start scanning to the initiation codon. Scanning on structured mRNAs additionally requires DHX29, a DExH-box protein that also binds directly to the 40S subunit. Here, we present a cryo-electron microscopy structure of the mammalian DHX29-bound 43S complex at 11.6 Å resolution. It reveals that eIF2 interacts with the 40S subunit via its α subunit and supports Met-tRNAi(Met) in an unexpected P/I orientation (eP/I). The structural core of eIF3 resides on the back of the 40S subunit, establishing two principal points of contact, whereas DHX29 binds around helix 16. The structure provides insights into eukaryote-specific aspects of translation, including the mechanism of action of DHX29.
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Affiliation(s)
- Yaser Hashem
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
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Levengood JD, Tolbert M, Li ML, Tolbert BS. High-affinity interaction of hnRNP A1 with conserved RNA structural elements is required for translation and replication of enterovirus 71. RNA Biol 2013; 10:1136-45. [PMID: 23727900 DOI: 10.4161/rna.25107] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Human Enterovirus 71 (EV71) is an emerging pathogen of infectious disease and a serious threat to public health. Currently, there are no antivirals or vaccines to slow down or prevent EV71 infections, thus underscoring the urgency to better understand mechanisms of host-enterovirus interactions. EV71 uses a type I internal ribosome entry site (IRES) to recruit the 40S ribosomal subunit via a pathway that requires the cytoplasmic localization of hnRNP A1, which acts as an IRES trans-activating factor. The mechanism of how hnRNP A1 trans activates EV71 RNA translation is unknown, however. Here, we report that the UP1 domain of hnRNP A1 interacts specifically with stem loop II (SLII) of the IRES, via a thermodynamically well-defined biphasic transition that involves conserved bulge 5'-AYAGY-3' and hairpin 5'-RY(U/A)CCA-3' loops. Calorimetric titrations of wild-type and mutant SLII constructs reveal these structural elements are essential to form a high-affinity UP1-SLII complex. Mutations that alter the bulge and hairpin primary or secondary structures abrogate the biphasic transition and destabilize the complex. Notably, mutations within the bulge that destabilize the complex correlate with a large reduction in IRES-dependent translational activity and impair EV71 replication. Taken together, this study shows that a conserved SLII structure is necessary to form a functional hnRNP A1-IRES complex, suggesting that small molecules that target this stem loop may have novel antiviral properties.
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