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Keep S, Dowgier G, Lulla V, Britton P, Oade M, Freimanis G, Tennakoon C, Jonassen CM, Tengs T, Bickerton E. Deletion of the s2m RNA Structure in the Avian Coronavirus Infectious Bronchitis Virus and Human Astrovirus Results in Sequence Insertions. J Virol 2023; 97:e0003823. [PMID: 36779761 PMCID: PMC10062133 DOI: 10.1128/jvi.00038-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/25/2023] [Indexed: 02/14/2023] Open
Abstract
Coronaviruses infect a wide variety of host species, resulting in a range of diseases in both humans and animals. The coronavirus genome consists of a large positive-sense single-stranded molecule of RNA containing many RNA structures. One structure, denoted s2m and consisting of 41 nucleotides, is located within the 3' untranslated region (3' UTR) and is shared between some coronavirus species, including infectious bronchitis virus (IBV), severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2, as well as other pathogens, including human astrovirus. Using a reverse genetic system to generate recombinant viruses, we investigated the requirement of the s2m structure in the replication of IBV, a globally distributed economically important Gammacoronavirus that infects poultry causing respiratory disease. Deletion of three nucleotides predicted to destabilize the canonical structure of the s2m or the deletion of the nucleotides corresponding to s2m impacted viral replication in vitro. In vitro passaging of the recombinant IBV with the s2m sequence deleted resulted in a 36-nucleotide insertion in place of the deletion, which was identified to be composed of a duplication of flanking sequences. A similar result was observed following serial passage of human astrovirus with a deleted s2m sequence. RNA modeling indicated that deletion of the nucleotides corresponding to the s2m impacted other RNA structures present in the IBV 3' UTR. Our results indicated for both IBV and human astrovirus a preference for nucleotide occupation in the genome location corresponding to the s2m, which is independent of the specific s2m sequence. IMPORTANCE Coronaviruses infect many species, including humans and animals, with substantial effects on livestock, particularly with respect to poultry. The coronavirus RNA genome consists of structural elements involved in viral replication whose roles are poorly understood. We investigated the requirement of the RNA structural element s2m in the replication of the Gammacoronavirus infectious bronchitis virus, an economically important viral pathogen of poultry. Using reverse genetics to generate recombinant IBVs with either a disrupted or deleted s2m, we showed that the s2m is not required for viral replication in cell culture; however, replication is decreased in tracheal tissue, suggesting a role for the s2m in the natural host. Passaging of these viruses as well as human astrovirus lacking the s2m sequence demonstrated a preference for nucleotide occupation, independent of the s2m sequence. RNA modeling suggested deletion of the s2m may negatively impact other essential RNA structures.
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Affiliation(s)
- Sarah Keep
- The Pirbright Institute, Woking, United Kingdom
| | | | - Valeria Lulla
- Department of Pathology, University of Cambridge, Addenbrookes Hospital, Cambridge, United Kingdom
| | | | - Michael Oade
- Department of Pathology, University of Cambridge, Addenbrookes Hospital, Cambridge, United Kingdom
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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Girgis S, Xu Z, Oikonomopoulos S, Fedorova AD, Tchesnokov EP, Gordon CJ, Schmeing TM, Götte M, Sonenberg N, Baranov PV, Ragoussis J, Hobman TC, Pelletier J. Evolution of naturally arising SARS-CoV-2 defective interfering particles. Commun Biol 2022; 5:1140. [PMID: 36302891 PMCID: PMC9610340 DOI: 10.1038/s42003-022-04058-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/30/2022] [Indexed: 11/23/2022] Open
Abstract
Defective interfering (DI) particles arise during virus propagation, are conditional on parental virus for replication and packaging, and interfere with viral expansion. There is much interest in developing DIs as anti-viral agents. Here we characterize DI particles that arose following serial passaging of SARS-CoV-2 at high multiplicity of infection. The prominent DIs identified have lost ~84% of the SARS-CoV-2 genome and are capable of attenuating parental viral titers. Synthetic variants of the DI genomes also interfere with infection and can be used as conditional, gene delivery vehicles. In addition, the DI genomes encode an Nsp1-10 fusion protein capable of attenuating viral replication. These results identify naturally selected defective viral genomes that emerged and stably propagated in the presence of parental virus. Genomes from defective interfering (DI) particles following serial passaging of SARS-CoV-2 reveal a fusion protein that attenuates viral replication. Synthetic, recombinant DI genomes are designed to interfere with SARS-CoV-2 replication.
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Affiliation(s)
- Samer Girgis
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Zaikun Xu
- Department of Cell Biology, U Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Spyros Oikonomopoulos
- McGill Genome Centre, Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Alla D Fedorova
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.,SFI Centre for Research Training in Genomics Data Science, University College Cork, Cork, Ireland
| | - Egor P Tchesnokov
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Calvin J Gordon
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - T Martin Schmeing
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Matthias Götte
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada.,Rosalind and Morris Goodman Cancer Institute, Montreal, QC, H3A 1A3, Canada
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Jiannis Ragoussis
- McGill Genome Centre, Department of Human Genetics, McGill University, Montreal, QC, Canada.,Department of Bioengineering, McGill University, Montreal, QC, Canada
| | - Tom C Hobman
- Department of Cell Biology, U Alberta, Edmonton, AB, T6G 2H7, Canada. .,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G 2E1, Canada. .,Li Ka Shing Institute of Virology, U Alberta, Edmonton, AB, T6G 2E1, Canada. .,Women & Children's Health Research Institute, U Alberta, Edmonton, AB, T6G 1C9, Canada.
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada. .,Rosalind and Morris Goodman Cancer Institute, Montreal, QC, H3A 1A3, Canada. .,Department of Oncology, McGill University, Montreal, QC, H3A 1G5, Canada.
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Yao S, Narayanan A, Majowicz SA, Jose J, Archetti M. A synthetic defective interfering SARS-CoV-2. PeerJ 2021; 9:e11686. [PMID: 34249513 PMCID: PMC8255065 DOI: 10.7717/peerj.11686] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/07/2021] [Indexed: 11/20/2022] Open
Abstract
Viruses thrive by exploiting the cells they infect, but in order to replicate and infect other cells they must produce viral proteins. As a result, viruses are also susceptible to exploitation by defective versions of themselves that do not produce such proteins. A defective viral genome with deletions in protein-coding genes could still replicate in cells coinfected with full-length viruses. Such a defective genome could even replicate faster due to its shorter size, interfering with the replication of the virus. We have created a synthetic defective interfering version of SARS-CoV-2, the virus causing the Covid-19 pandemic, assembling parts of the viral genome that do not code for any functional protein but enable the genome to be replicated and packaged. This synthetic defective genome replicates three times faster than SARS-CoV-2 in coinfected cells, and interferes with it, reducing the viral load of infected cells by half in 24 hours. The synthetic genome is transmitted as efficiently as the full-length genome, suggesting the location of the putative packaging signal of SARS-CoV-2. A version of such a synthetic construct could be used as a self-promoting antiviral therapy: by enabling replication of the synthetic genome, the virus would promote its own demise.
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Affiliation(s)
- Shun Yao
- Department of Biology, Pennsylvania State University, University Park, United States of America
| | - Anoop Narayanan
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, United States of America
| | - Sydney A Majowicz
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, United States of America
| | - Joyce Jose
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, United States of America.,The Huck Institutes for the Life Sciences, Pennsylvania State University, University Park, United States of America
| | - Marco Archetti
- Department of Biology, Pennsylvania State University, University Park, United States of America.,The Huck Institutes for the Life Sciences, Pennsylvania State University, University Park, United States of America
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Chen H, Gill A, Dove BK, Emmett SR, Kemp CF, Ritchie MA, Dee M, Hiscox JA. Mass spectroscopic characterization of the coronavirus infectious bronchitis virus nucleoprotein and elucidation of the role of phosphorylation in RNA binding by using surface plasmon resonance. J Virol 2005; 79:1164-79. [PMID: 15613344 PMCID: PMC538594 DOI: 10.1128/jvi.79.2.1164-1179.2005] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 07/05/2004] [Indexed: 12/15/2022] Open
Abstract
Phosphorylation of the coronavirus nucleoprotein (N protein) has been predicted to play a role in RNA binding. To investigate this hypothesis, we examined the kinetics of RNA binding between nonphosphorylated and phosphorylated infectious bronchitis virus N protein with nonviral and viral RNA by surface plasmon resonance (Biacore). Mass spectroscopic analysis of N protein identified phosphorylation sites that were proximal to RNA binding domains. Kinetic analysis, by surface plasmon resonance, indicated that nonphosphorylated N protein bound with the same affinity to viral RNA as phosphorylated N protein. However, phosphorylated N protein bound to viral RNA with a higher binding affinity than nonviral RNA, suggesting that phosphorylation of N protein determined the recognition of virus RNA. The data also indicated that a known N protein binding site (involved in transcriptional regulation) consisting of a conserved core sequence present near the 5' end of the genome (in the leader sequence) functioned by promoting high association rates of N protein binding. Further analysis of the leader sequence indicated that the core element was not the only binding site for N protein and that other regions functioned to promote high-affinity binding.
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Affiliation(s)
- Hongying Chen
- School of Animal and Microbial Sciences, University of Reading, Reading, United Kingdom
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Izeta A, Smerdou C, Alonso S, Penzes Z, Mendez A, Plana-Durán J, Enjuanes L. Replication and packaging of transmissible gastroenteritis coronavirus-derived synthetic minigenomes. J Virol 1999; 73:1535-45. [PMID: 9882359 PMCID: PMC103978 DOI: 10.1128/jvi.73.2.1535-1545.1999] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/1998] [Accepted: 11/09/1998] [Indexed: 11/20/2022] Open
Abstract
The sequences involved in the replication and packaging of transmissible gastroenteritis virus (TGEV) RNA have been studied. The structure of a TGEV defective interfering RNA of 9.7 kb (DI-C) was described previously (A. Mendez, C. Smerdou, A. Izeta, F. Gebauer, and L. Enjuanes, Virology 217: 495-507, 1996), and a cDNA with the information to encode DI-C RNA was cloned under the control of the T7 promoter. The molecularly cloned DI-C RNA was replicated in trans upon transfection of helper virus-infected cells and inhibited 20-fold the replication of the parental genome. A collection of 14 DI-C RNA deletion mutants (TGEV minigenomes) was synthetically generated and tested for their ability to be replicated and packaged. The smallest minigenome (M33) that was replicated by the helper virus and efficiently packaged was 3.3 kb. A minigenome of 2.1 kb (M21) was also replicated, but it was packaged with much lower efficiency than the M33 minigenome, suggesting that it had lost either the sequences containing the main packaging signal or the required secondary structure in the packaging signal due to alteration of the flanking sequences. The low packaging efficiency of the M21 minigenome was not due to minimum size restrictions. The sequences essential for minigenome replication by the helper virus were reduced to 1,348 nt and 492 nt at the 5' and 3' ends, respectively. The TGEV-derived RNA minigenomes were successfully expressed following a two-step amplification system that couples pol II-driven transcription in the nucleus to replication supported by helper virus in the cytoplasm, without any obvious splicing. This system and the use of the reporter gene beta-glucuronidase (GUS) allowed minigenome detection at passage zero, making it possible to distinguish replication efficiency from packaging capability. The synthetic minigenomes have been used to design a helper-dependent expression system that produces around 1.0 microgram/10(6) cells of GUS.
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Affiliation(s)
- A Izeta
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Campus Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
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