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Tamura T, Yamamoto H, Ogino S, Morioka Y, Tsujino S, Suzuki R, Hiono T, Suzuki S, Isoda N, Sakoda Y, Fukuhara T. A rapid and versatile reverse genetics approach for generating recombinant positive-strand RNA viruses that use IRES-mediated translation. J Virol 2024; 98:e0163823. [PMID: 38353536 PMCID: PMC10949505 DOI: 10.1128/jvi.01638-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/24/2024] [Indexed: 03/20/2024] Open
Abstract
Reverse genetics systems have played a central role in developing recombinant viruses for a wide spectrum of virus research. The circular polymerase extension reaction (CPER) method has been applied to studying positive-strand RNA viruses, allowing researchers to bypass molecular cloning of viral cDNA clones and thus leading to the rapid generation of recombinant viruses. However, thus far, the CPER protocol has only been established using cap-dependent RNA viruses. Here, we demonstrate that a modified version of the CPER method can be successfully applied to positive-strand RNA viruses that use cap-independent, internal ribosomal entry site (IRES)-mediated translation. As a proof-of-concept, we employed mammalian viruses with different types (classes I, II, and III) of IRES to optimize the CPER method. Using the hepatitis C virus (HCV, class III), we found that inclusion in the CPER assembly of an RNA polymerase I promoter and terminator, instead of those from polymerase II, allowed greater viral production. This approach was also successful in generating recombinant bovine viral diarrhea virus (class III) following transfection of MDBK/293T co-cultures to overcome low transfection efficiency. In addition, we successfully generated the recombinant viruses from clinical specimens. Our modified CPER could be used for producing hepatitis A virus (HAV, type I) as well as de novo generation of encephalomyocarditis virus (type II). Finally, we generated recombinant HCV and HAV reporter viruses that exhibited replication comparable to that of the wild-type parental viruses. The recombinant HAV reporter virus helped evaluate antivirals. Taking the findings together, this study offers methodological advances in virology. IMPORTANCE The lack of versatility of reverse genetics systems remains a bottleneck in viral research. Especially when (re-)emerging viruses reach pandemic levels, rapid characterization and establishment of effective countermeasures using recombinant viruses are beneficial in disease control. Indeed, numerous studies have attempted to establish and improve the methods. The circular polymerase extension reaction (CPER) method has overcome major obstacles in generating recombinant viruses. However, this method has not yet been examined for positive-strand RNA viruses that use cap-independent, internal ribosome entry site-mediated translation. Here, we engineered a suitable gene cassette to expand the CPER method for all positive-strand RNA viruses. Furthermore, we overcame the difficulty of generating recombinant viruses because of low transfection efficiency. Using this modified method, we also successfully generated reporter viruses and recombinant viruses from a field sample without virus isolation. Taking these findings together, our adapted methodology is an innovative technology that could help advance virologic research.
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Affiliation(s)
- Tomokazu Tamura
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
- One Health Research Center, Hokkaido University, Sapporo, Japan
| | - Hirotaka Yamamoto
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Saho Ogino
- Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yuhei Morioka
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Shuhei Tsujino
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Rigel Suzuki
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
| | - Takahiro Hiono
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
- One Health Research Center, Hokkaido University, Sapporo, Japan
- Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Saori Suzuki
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
| | - Norikazu Isoda
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
- One Health Research Center, Hokkaido University, Sapporo, Japan
- Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Yoshihiro Sakoda
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
- One Health Research Center, Hokkaido University, Sapporo, Japan
- Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
- International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Takasuke Fukuhara
- Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
- Institute for Vaccine Research and Development (IVReD), Hokkaido University, Sapporo, Japan
- One Health Research Center, Hokkaido University, Sapporo, Japan
- Laboratory of Virus Control, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
- AMED-CREST, Japan Agency for Medical Research and Development (AMED), Tokyo, Japan
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Cheng X, Wu X, Fang R. The minus strand of positive-sense RNA viruses encodes small proteins. Trends Microbiol 2024; 32:6-7. [PMID: 37951770 DOI: 10.1016/j.tim.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023]
Abstract
It is widely accepted that the minus strands of positive single-strand RNA (+ssRNA) viruses function as replication templates only. Gong et al. revealed that the minus strand of two unrelated +ssRNA viruses encodes proteins. This textbook-changing discovery calls for the reconsideration of the molecular mechanisms underlying the infection cycle of +ssRNA viruses.
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Affiliation(s)
- Xiaofei Cheng
- College of Plant Protection/Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region of Chinese Education Ministry, Northeast Agricultural University, 150030 Harbin, Heilongjiang, China.
| | - Xiaoyun Wu
- College of Plant Protection/Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region of Chinese Education Ministry, Northeast Agricultural University, 150030 Harbin, Heilongjiang, China
| | - Rongxiang Fang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
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Grellet E, L'Hôte I, Goulet A, Imbert I. Replication of the coronavirus genome: A paradox among positive-strand RNA viruses. J Biol Chem 2022; 298:101923. [PMID: 35413290 PMCID: PMC8994683 DOI: 10.1016/j.jbc.2022.101923] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 01/18/2023] Open
Abstract
Coronavirus (CoV) genomes consist of positive-sense single-stranded RNA and are among the largest viral RNAs known to date (∼30 kb). As a result, CoVs deploy sophisticated mechanisms to replicate these extraordinarily large genomes as well as to transcribe subgenomic messenger RNAs. Since 2003, with the emergence of three highly pathogenic CoVs (SARS-CoV, MERS-CoV, and SARS-CoV-2), significant progress has been made in the molecular characterization of the viral proteins and key mechanisms involved in CoV RNA genome replication. For example, to allow for the maintenance and integrity of their large RNA genomes, CoVs have acquired RNA proofreading 3'-5' exoribonuclease activity (in nonstructural protein nsp14). In order to replicate the large genome, the viral-RNA-dependent RNA polymerase (RdRp; in nsp12) is supplemented by a processivity factor (made of the viral complex nsp7/nsp8), making it the fastest known RdRp. Lastly, a viral structural protein, the nucleocapsid (N) protein, which is primarily involved in genome encapsidation, is required for efficient viral replication and transcription. Therefore, CoVs are a paradox among positive-strand RNA viruses in the sense that they use both a processivity factor and have proofreading activity reminiscent of DNA organisms in addition to structural proteins that mediate efficient RNA synthesis, commonly used by negative-strand RNA viruses. In this review, we present a historical perspective of these unsuspected discoveries and detail the current knowledge on the core replicative machinery deployed by CoVs.
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Affiliation(s)
- Emeline Grellet
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - India L'Hôte
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - Adeline Goulet
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France
| | - Isabelle Imbert
- Aix Marseille Université, Centre National de la Recherche Scientifique, AMU CNRS UMR 7255, LISM, Marseille, France.
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Meki IK, Huditz HI, Strunov A, van der Vlugt RAA, Kariithi HM, Rezapanah M, Miller WJ, Vlak JM, van Oers MM, Abd-Alla AMM. Characterization and Tissue Tropism of Newly Identified Iflavirus and Negeviruses in Glossina morsitans morsitans Tsetse Flies. Viruses 2021; 13:v13122472. [PMID: 34960741 PMCID: PMC8704047 DOI: 10.3390/v13122472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/26/2022] Open
Abstract
Tsetse flies cause major health and economic problems as they transmit trypanosomes causing sleeping sickness in humans (Human African Trypanosomosis, HAT) and nagana in animals (African Animal Trypanosomosis, AAT). A solution to control the spread of these flies and their associated diseases is the implementation of the Sterile Insect Technique (SIT). For successful application of SIT, it is important to establish and maintain healthy insect colonies and produce flies with competitive fitness. However, mass production of tsetse is threatened by covert virus infections, such as the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV). This virus infection can switch from a covert asymptomatic to an overt symptomatic state and cause the collapse of an entire fly colony. Although the effects of GpSGHV infections can be mitigated, the presence of other covert viruses threaten tsetse mass production. Here we demonstrated the presence of two single-stranded RNA viruses isolated from Glossina morsitans morsitans originating from a colony at the Seibersdorf rearing facility. The genome organization and the phylogenetic analysis based on the RNA-dependent RNA polymerase (RdRp) revealed that the two viruses belong to the genera Iflavirus and Negevirus, respectively. The names proposed for the two viruses are Glossina morsitans morsitans iflavirus (GmmIV) and Glossina morsitans morsitans negevirus (GmmNegeV). The GmmIV genome is 9685 nucleotides long with a poly(A) tail and encodes a single polyprotein processed into structural and non-structural viral proteins. The GmmNegeV genome consists of 8140 nucleotides and contains two major overlapping open reading frames (ORF1 and ORF2). ORF1 encodes the largest protein which includes a methyltransferase domain, a ribosomal RNA methyltransferase domain, a helicase domain and a RdRp domain. In this study, a selective RT-qPCR assay to detect the presence of the negative RNA strand for both GmmIV and GmmNegeV viruses proved that both viruses replicate in G. m. morsitans. We analyzed the tissue tropism of these viruses in G. m. morsitans by RNA-FISH to decipher their mode of transmission. Our results demonstrate that both viruses can be found not only in the host’s brain and fat bodies but also in their reproductive organs, and in milk and salivary glands. These findings suggest a potential horizontal viral transmission during feeding and/or a vertically viral transmission from parent to offspring. Although the impact of GmmIV and GmmNegeV in tsetse rearing facilities is still unknown, none of the currently infected tsetse species show any signs of disease from these viruses.
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Affiliation(s)
- Irene K. Meki
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
| | - Hannah-Isadora Huditz
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Anton Strunov
- Lab Genome Dynamics, Department Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (A.S.); (W.J.M.)
| | - René A. A. van der Vlugt
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Henry M. Kariithi
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, USDA-ARS, Athens, GA 30605, USA
- Biotechnology Research Center, Kenya Agricultural and Livestock Research Organization, Nairobi P.O. Box 57811-00200, Kenya
| | - Mohammadreza Rezapanah
- Iranian Research Institute of Plant Protection (IRIPP), Agricultural Research Education and Extension Organization (AREEO), Tehran 19395, Iran;
| | - Wolfgang J. Miller
- Lab Genome Dynamics, Department Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (A.S.); (W.J.M.)
| | - Just M. Vlak
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Monique M. van Oers
- Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands; (R.A.A.v.d.V.); (J.M.V.); (M.M.v.O.)
| | - Adly M. M. Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria; (I.K.M.); (H.-I.H.); (H.M.K.)
- Correspondence: ; Tel.: +43-12-60-02-84-25
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Eruera AR, McSweeney AM, McKenzie-Goldsmith GM, Ward VK. Protein Nucleotidylylation in +ssRNA Viruses. Viruses 2021; 13:1549. [PMID: 34452414 PMCID: PMC8402628 DOI: 10.3390/v13081549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 12/22/2022] Open
Abstract
Nucleotidylylation is a post-transcriptional modification important for replication in the picornavirus supergroup of RNA viruses, including members of the Caliciviridae, Coronaviridae, Picornaviridae and Potyviridae virus families. This modification occurs when the RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a target protein through a nucleotidyl-transferase reaction. The most characterized nucleotidylylation target is VPg (viral protein genome-linked), a protein linked to the 5' end of the genome in Caliciviridae, Picornaviridae and Potyviridae. The nucleotidylylation of VPg by RdRp is a critical step for the VPg protein to act as a primer for genome replication and, in Caliciviridae and Potyviridae, for the initiation of translation. In contrast, Coronaviridae do not express a VPg protein, but the nucleotidylylation of proteins involved in replication initiation is critical for genome replication. Furthermore, the RdRp proteins of the viruses that perform nucleotidylylation are themselves nucleotidylylated, and in the case of coronavirus, this has been shown to be essential for viral replication. This review focuses on nucleotidylylation within the picornavirus supergroup of viruses, including the proteins that are modified, what is known about the nucleotidylylation process and the roles that these modifications have in the viral life cycle.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand; (A.-R.E.); (A.M.M.); (G.M.M.-G.)
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Carvalho Costa L, Stevens K, Hu X, Fuchs M, Al Rwahnih M, Diaz-Lara A, McFarland C, Foster J, Hurtado-Gonzales OP. Identification and characterization of a novel virus associated with an eriophyid mite in extracts of fruit trees leaves. Arch Virol 2021; 166:2869-2873. [PMID: 34292373 DOI: 10.1007/s00705-021-05174-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 05/27/2021] [Indexed: 11/26/2022]
Abstract
Eriophyid mites are commonly found on the leaf surface of different plant species. In the present study, a novel virus associated with an eriophyid mite species was detected using high-throughput sequencing (HTS) of total RNA from fruit tree leaves, primarily growing under greenhouse conditions. The complete genome sequence was characterized using rapid amplification of cDNA ends followed by Sanger sequencing, revealing a genome of 8885 nucleotides in length. The single positive-stranded RNA genome was predicted to encode typical conserved domains of members of the genus Iflavirus in the family Iflaviridae. Phylogenetic analysis showed this virus to be closely related to the unclassified iflavirus tomato matilda associated virus (TMaV), with a maximum amino acid sequence identity of 59% in the RNA-dependent RNA polymerase domain. This low identity value justifies the recognition of the novel virus as a potential novel iflavirus. In addition to a lack of graft-transmissibility evidence, RT-PCR and HTS detection of this virus in the putative host plants were not consistent through different years and growing seasons, raising the possibility that rather than a plant virus, this was a virus infecting an organism associated with fruit tree leaves. Identification of Tetra pinnatifidae HTS-derived contigs in all fruit tree samples carrying the novel virus suggested this mite as the most likely host of the new virus (p-value < 1e-11), which is tentatively named "eriophyid mite-associated virus" (EMaV). This study highlights the importance of a careful biological study before assigning a new virus to a particular plant host when using metagenomics data.
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Affiliation(s)
- Larissa Carvalho Costa
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Germplasm Quarantine Program, Beltsville, MD, USA
| | - Kristian Stevens
- Department of Evolution and Ecology, University of California-Davis, Davis, CA, USA
- Department of Plant Pathology, University of California-Davis, Davis, CA, USA
| | - Xiaojun Hu
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Germplasm Quarantine Program, Beltsville, MD, USA
| | - Marc Fuchs
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Cornell University, Geneva, NY, USA
| | - Maher Al Rwahnih
- Department of Plant Pathology, University of California-Davis, Davis, CA, USA
| | - Alfredo Diaz-Lara
- Tecnologico de Monterrey, School of Engineering and Sciences, Campus Queretaro, Queretaro, Mexico
| | - Clint McFarland
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine, Field Operations, Raleigh, NC, USA
| | - Joseph Foster
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Germplasm Quarantine Program, Beltsville, MD, USA
| | - Oscar P Hurtado-Gonzales
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Germplasm Quarantine Program, Beltsville, MD, USA.
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Langeberg CJ, Sherlock ME, MacFadden A, Kieft JS. An expanded class of histidine-accepting viral tRNA-like structures. RNA 2021; 27:653-664. [PMID: 33811147 PMCID: PMC8127992 DOI: 10.1261/rna.078550.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/30/2021] [Indexed: 05/12/2023]
Abstract
Structured RNA elements are common in the genomes of RNA viruses, often playing critical roles during viral infection. Some viral RNA elements use forms of tRNA mimicry, but the diverse ways this mimicry can be achieved are poorly understood. Histidine-accepting tRNA-like structures (TLSHis) are examples found at the 3' termini of some positive-sense single-stranded RNA (+ssRNA) viruses where they interact with several host proteins, induce histidylation of the RNA genome, and facilitate processes important for infection, to include genome replication. As only five TLSHis examples had been reported, we explored the possible larger phylogenetic distribution and diversity of this TLS class using bioinformatic approaches. We identified many new examples of TLSHis, yielding a rigorous consensus sequence and secondary structure model that we validated by chemical probing of representative TLSHis RNAs. We confirmed new examples as authentic TLSHis by demonstrating their ability to be histidylated in vitro, then used mutational analyses to imply a tertiary interaction that is likely analogous to the D- and T-loop interaction found in canonical tRNAs. These results expand our understanding of how diverse RNA sequences achieve tRNA-like structure and function in the context of viral RNA genomes and lay the groundwork for high-resolution structural studies of tRNA mimicry by histidine-accepting TLSs.
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Affiliation(s)
- Conner J Langeberg
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Madeline E Sherlock
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Andrea MacFadden
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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Lüthi MN, Vorburger C, Dennis AB. A Novel RNA Virus in the Parasitoid Wasp Lysiphlebus fabarum: Genomic Structure, Prevalence, and Transmission. Viruses 2020; 12:E59. [PMID: 31947801 PMCID: PMC7019493 DOI: 10.3390/v12010059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/19/2019] [Accepted: 12/31/2019] [Indexed: 12/30/2022] Open
Abstract
We report on a novel RNA virus infecting the wasp Lysiphlebus fabarum, a parasitoid of aphids. This virus, tentatively named "Lysiphlebus fabarum virus" (LysV), was discovered in transcriptome sequences of wasps from an experimental evolution study in which the parasitoids were allowed to adapt to aphid hosts (Aphis fabae) with or without resistance-conferring endosymbionts. Based on phylogenetic analyses of the viral RNA-dependent RNA polymerase (RdRp), LysV belongs to the Iflaviridae family in the order of the Picornavirales, with the closest known relatives all being parasitoid wasp-infecting viruses. We developed an endpoint PCR and a more sensitive qPCR assay to screen for LysV in field samples and laboratory lines. These screens verified the occurrence of LysV in wild parasitoids and identified the likely wild-source population for lab infections in Western Switzerland. Three viral haplotypes could be distinguished in wild populations, of which two were found in the laboratory. Both vertical and horizontal transmission of LysV were demonstrated experimentally, and repeated sampling of laboratory populations suggests that the virus can form persistent infections without obvious symptoms in infected wasps.
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Affiliation(s)
- Martina N. Lüthi
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Christoph Vorburger
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Alice B. Dennis
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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