1
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Wang X, Hao X, Zhao Y, Xiao X, Li S, Zhou P. Canine parvovirus NS1 induces host translation shutoff by reducing mTOR phosphorylation. J Virol 2025; 99:e0146324. [PMID: 39601560 PMCID: PMC11784071 DOI: 10.1128/jvi.01463-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Accepted: 11/01/2024] [Indexed: 11/29/2024] Open
Abstract
Canine parvovirus type 2 (CPV-2) is a member of the Parvoviridae family, characterized by its small, non-enveloped virions containing a linear single-stranded DNA genome of approximately 5 kb. Parvoviruses entirely reliant on the host cell's division machinery for replication. In this study, we demonstrate that CPV-2 infection triggers the host translation shutoff, a process in which the nonstructural protein 1 (NS1) plays a pivotal role. Our findings indicate that the CPV-2 NS1-induced host translation shutoff is not associated with transcription, protein degradation pathways, or eIFα phosphorylation, but rather involves the reduction of phosphorylation of the mammalian target of rapamycin (mTOR). In conclusion, this research reveals that CPV-2 NS1 induces a host translation shutoff by reducing mTOR phosphorylation, a mechanism that could potentially inform the development of more efficacious control and therapeutic strategies for CPV-2 and other parvoviral infections. IMPORTANCE Autonomous parvoviruses, which possess compact genomes, are obligate intracellular parasites that necessitate host cell division for their replication cycle. Consequently, the modulation of host translation and usurpation of cellular machinery are hypothesized to facilitate immune evasion, enhance viral transmission, and perpetuate long-term infection. Despite the biological significance, the precise mechanisms by which autonomous parvoviruses regulate host translation remain understudied. Our study elucidates that CPV-2 infection induces a shutoff of host translation through the attenuation of mTOR phosphorylation. This mechanism may enable the virus to subvert the host immune response and engender pathogenic effects.
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Affiliation(s)
- Xinrui Wang
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiangqi Hao
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yaning Zhao
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiangyu Xiao
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Shoujun Li
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Pei Zhou
- Guangdong Technological Engineering Research Center for Pets, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
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2
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Rozek W, Kwasnik M, Socha W, Czech B, Rola J. Profiling of snoRNAs in Exosomes Secreted from Cells Infected with Influenza A Virus. Int J Mol Sci 2024; 26:12. [PMID: 39795871 PMCID: PMC11720657 DOI: 10.3390/ijms26010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2024] [Revised: 12/18/2024] [Accepted: 12/21/2024] [Indexed: 01/13/2025] Open
Abstract
Small nucleolar RNAs (snoRNAs) are non-coding RNAs (ncRNAs) that regulate many cellular processes. Changes in the profiles of cellular ncRNAs and those secreted in exosomes are observed during viral infection. In our study, we analysed differences in expression profiles of snoRNAs isolated from exosomes of influenza (IAV)-infected and non-infected MDCK cells using high-throughput sequencing. The analysis revealed 133 significantly differentially regulated snoRNAs (131 upregulated and 2 downregulated), including 93 SNORD, 38 SNORA, and 2 SCARNA. The most upregulated was SNORD58 (log2FoldChange = 9.61), while the only downregulated snoRNAs were SNORD3 (log2FC = -2.98) and SNORA74 (log2FC = -2.67). Several snoRNAs previously described as involved in viral infections were upregulated, including SNORD27, SNORD28, SNORD29, SNORD58, and SNORD44. In total, 533 interactors of dysregulated snoRNAs were identified using the RNAinter database with an assigned confidence score ≥ 0.25. The main groups of predicted interactors were transcription factors (TFs, 169 interactors) and RNA-binding proteins (RBPs, 130 interactors). Among the most important were pioneer TFs such as POU5F1, SOX2, CEBPB, and MYC, while in the RBP category, notable interactors included Polr2a, TNRC6A, IGF2BP3, and FMRP. Our results suggest that snoRNAs are involved in pro-viral activity, although follow-up studies including experimental validation would be beneficial.
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Affiliation(s)
- Wojciech Rozek
- Department of Virology, National Veterinary Research Institute, 24-100 Pulawy, Poland; (M.K.); (W.S.); (J.R.)
| | - Malgorzata Kwasnik
- Department of Virology, National Veterinary Research Institute, 24-100 Pulawy, Poland; (M.K.); (W.S.); (J.R.)
| | - Wojciech Socha
- Department of Virology, National Veterinary Research Institute, 24-100 Pulawy, Poland; (M.K.); (W.S.); (J.R.)
| | | | - Jerzy Rola
- Department of Virology, National Veterinary Research Institute, 24-100 Pulawy, Poland; (M.K.); (W.S.); (J.R.)
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3
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Elshina E, Pitre E, Mendes M, Schweibenz B, Fan RLY, French H, Park JW, Wang W, Poon LLM, Marcotrigiano J, Russell AB, Te Velthuis AJW. Influenza A virus transcription generates capped cRNAs that activate RIG-I. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.11.12.623191. [PMID: 39605425 PMCID: PMC11601390 DOI: 10.1101/2024.11.12.623191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2024]
Abstract
During influenza A virus (IAV) infection, host pathogen receptor retinoic acid-inducible gene I (RIG-I) detects the partially complementary, 5'-triphosphorylated ends of the viral genome segments and non-canonical replication products. However, it has also been suggested that innate immune responses may be triggered by viral transcription. In this study, we investigated whether an immunostimulatory RNA is produced during IAV transcription. We show that the IAV RNA polymerase can read though the polyadenylation signal during transcription termination, generating a capped complementary RNA (ccRNA), which contains the 5' cap of an IAV mRNA and the 3' terminus of a cRNA instead of a poly(A) tail. ccRNAs are detectable in vitro and in both ribonucleoprotein reconstitution assays and IAV infections. Mutations that disrupt polyadenylation enhance ccRNA synthesis and increase RIG-I-dependent innate immune activation. Notably, while ccRNA itself is not immunostimulatory, it forms a RIG-I agonist by hybridizing with a complementary negative-sense viral RNA. These findings thus identify a novel non-canonical IAV RNA species and suggest an alternative mechanism for RIG-I activation during IAV infection.
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4
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Huang Y, Urban C, Hubel P, Stukalov A, Pichlmair A. Protein turnover regulation is critical for influenza A virus infection. Cell Syst 2024; 15:911-929.e8. [PMID: 39368468 DOI: 10.1016/j.cels.2024.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 08/16/2024] [Accepted: 09/13/2024] [Indexed: 10/07/2024]
Abstract
The abundance of a protein is defined by its continuous synthesis and degradation, a process known as protein turnover. Here, we systematically profiled the turnover of proteins in influenza A virus (IAV)-infected cells using a pulse-chase stable isotope labeling by amino acids in cell culture (SILAC)-based approach combined with downstream statistical modeling. We identified 1,798 virus-affected proteins with turnover changes (tVAPs) out of 7,739 detected proteins (data available at pulsechase.innatelab.org). In particular, the affected proteins were involved in RNA transcription, splicing and nuclear transport, protein translation and stability, and energy metabolism. Many tVAPs appeared to be known IAV-interacting proteins that regulate virus propagation, such as KPNA6, PPP6C, and POLR2A. Notably, our analysis identified additional IAV host and restriction factors, such as the splicing factor GPKOW, that exhibit significant turnover rate changes while their total abundance is minimally affected. Overall, we show that protein turnover is a critical factor both for virus replication and antiviral defense.
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Affiliation(s)
- Yiqi Huang
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Christian Urban
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Philipp Hubel
- Core Facility Hohenheim, Universität Hohenheim, Stuttgart, Germany
| | - Alexey Stukalov
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Andreas Pichlmair
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany; Institute of Virology, Helmholtz Munich, Munich, Germany; German Centre for Infection Research (DZIF), Partner Site, Munich, Germany.
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5
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Wang D, Booth JL, Wu W, Kiger N, Lettow M, Bates A, Pan C, Metcalf J, Schroeder SJ. Nanopore Direct RNA Sequencing Reveals Virus-Induced Changes in the Transcriptional Landscape in Human Bronchial Epithelial Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.26.600852. [PMID: 38979243 PMCID: PMC11230378 DOI: 10.1101/2024.06.26.600852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Direct RNA nanopore sequencing reveals changes in gene expression, polyadenylation, splicing, m6A methylation, and pseudouridylation in response to influenza virus exposure in primary human bronchial epithelial cells. This study focuses on the epitranscriptomic profile of genes in the host immune response. In addition to polyadenylated noncoding RNA, we purified and sequenced nonpolyadenylated noncoding RNA and observed changes in expression, N6-methyl-adenosine (m6A), and pseudouridylation (Ψ) in these novel RNA. Two recently discovered lincRNA with roles in immune response, Chaserr and LEADR , became highly methylated in response to influenza exposure. Several H/ACA type snoRNAs that guide pseudouridylation are decreased in expression in response to influenza, and there is a corresponding decrease in the pseudouridylation of two novel lncRNA. Thus, novel epitranscriptomic changes revealed by direct RNA sequencing with nanopore technology provides unique insights into the host epitranscriptomic changes in epithelial gene networks that respond to influenza virus infection.
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6
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Ribeiro DR, Nunes A, Ribeiro D, Soares AR. The hidden RNA code: implications of the RNA epitranscriptome in the context of viral infections. Front Genet 2023; 14:1245683. [PMID: 37614818 PMCID: PMC10443596 DOI: 10.3389/fgene.2023.1245683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 07/19/2023] [Indexed: 08/25/2023] Open
Abstract
Emerging evidence highlights the multifaceted roles of the RNA epitranscriptome during viral infections. By modulating the modification landscape of viral and host RNAs, viruses enhance their propagation and elude host surveillance mechanisms. Here, we discuss how specific RNA modifications, in either host or viral RNA molecules, impact the virus-life cycle and host antiviral responses, highlighting the potential of targeting the RNA epitranscriptome for novel antiviral therapies.
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7
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Xie E, Ahmad S, Smyth RP, Sieben C. Advanced fluorescence microscopy in respiratory virus cell biology. Adv Virus Res 2023; 116:123-172. [PMID: 37524480 DOI: 10.1016/bs.aivir.2023.05.002] [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: 08/02/2023]
Abstract
Respiratory viruses are a major public health burden across all age groups around the globe, and are associated with high morbidity and mortality rates. They can be transmitted by multiple routes, including physical contact or droplets and aerosols, resulting in efficient spreading within the human population. Investigations of the cell biology of virus replication are thus of utmost importance to gain a better understanding of virus-induced pathogenicity and the development of antiviral countermeasures. Light and fluorescence microscopy techniques have revolutionized investigations of the cell biology of virus infection by allowing the study of the localization and dynamics of viral or cellular components directly in infected cells. Advanced microscopy including high- and super-resolution microscopy techniques available today can visualize biological processes at the single-virus and even single-molecule level, thus opening a unique view on virus infection. We will highlight how fluorescence microscopy has supported investigations on virus cell biology by focusing on three major respiratory viruses: respiratory syncytial virus (RSV), Influenza A virus (IAV) and SARS-CoV-2. We will review our current knowledge of virus replication and highlight how fluorescence microscopy has helped to improve our state of understanding. We will start by introducing major imaging and labeling modalities and conclude the chapter with a perspective discussion on remaining challenges and potential opportunities.
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Affiliation(s)
- Enyu Xie
- Nanoscale Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Shazeb Ahmad
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Redmond P Smyth
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany; Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Christian Sieben
- Nanoscale Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany; Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany.
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8
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Gaucherand L, Iyer A, Gilabert I, Rycroft CH, Gaglia MM. Cut site preference allows influenza A virus PA-X to discriminate between host and viral mRNAs. Nat Microbiol 2023; 8:1304-1317. [PMID: 37349586 PMCID: PMC10690756 DOI: 10.1038/s41564-023-01409-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 05/10/2023] [Indexed: 06/24/2023]
Abstract
Many viruses block host gene expression to take over the infected cell. This process, termed host shutoff, is thought to promote viral replication by preventing antiviral responses and redirecting cellular resources to viral processes. Several viruses from divergent families accomplish host shutoff through RNA degradation by endoribonucleases. However, viruses also need to ensure expression of their own genes. The influenza A virus endoribonuclease PA-X solves this problem by sparing viral mRNAs and some host RNAs necessary for viral replication. To understand how PA-X distinguishes between RNAs, we characterized PA-X cut sites transcriptome-wide using 5' rapid amplification of complementary DNA ends coupled to high-throughput sequencing. This analysis, along with RNA structure predictions and validation experiments using reporters, shows that PA-Xs from multiple influenza strains preferentially cleave RNAs at GCUG tetramers in hairpin loops. Importantly, GCUG tetramers are enriched in the human but not the influenza transcriptome. Moreover, optimal PA-X cut sites inserted in the influenza A virus genome are quickly selected against during viral replication in cells. This finding suggests that PA-X evolved these cleavage characteristics to preferentially target host over viral mRNAs in a manner reminiscent of cellular self versus non-self discrimination.
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Affiliation(s)
- Lea Gaucherand
- Program in Molecular Microbiology, Tufts University Graduate School of Biomedical Sciences, Boston, MA, USA
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
- Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, Strasbourg, France
| | - Amrita Iyer
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - Isabel Gilabert
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Madrid, Spain
| | - Chris H Rycroft
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Mathematics, University of Wisconsin-Madison, Madison, WI, USA
| | - Marta M Gaglia
- Program in Molecular Microbiology, Tufts University Graduate School of Biomedical Sciences, Boston, MA, USA.
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.
- Institute for Molecular Virology and Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.
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9
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Rodríguez-Molina JB, West S, Passmore LA. Knowing when to stop: Transcription termination on protein-coding genes by eukaryotic RNAPII. Mol Cell 2023; 83:404-415. [PMID: 36634677 PMCID: PMC7614299 DOI: 10.1016/j.molcel.2022.12.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023]
Abstract
Gene expression is controlled in a dynamic and regulated manner to allow for the consistent and steady expression of some proteins as well as the rapidly changing production of other proteins. Transcription initiation has been a major focus of study because it is highly regulated. However, termination of transcription also plays an important role in controlling gene expression. Transcription termination on protein-coding genes is intimately linked with 3' end cleavage and polyadenylation of transcripts, and it generally results in the production of a mature mRNA that is exported from the nucleus. Termination on many non-coding genes can also result in the production of a mature transcript. Termination is dynamically regulated-premature termination and transcription readthrough occur in response to a number of cellular signals, and these can have varied consequences on gene expression. Here, we review eukaryotic transcription termination by RNA polymerase II (RNAPII), focusing on protein-coding genes.
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Affiliation(s)
| | - Steven West
- The Living Systems Institute, University of Exeter, Exeter, UK.
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10
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Strategies of Influenza A Virus to Ensure the Translation of Viral mRNAs. Pathogens 2022; 11:pathogens11121521. [PMID: 36558855 PMCID: PMC9783940 DOI: 10.3390/pathogens11121521] [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: 11/23/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Viruses are obligatorily intracellular pathogens. To generate progeny virus particles, influenza A viruses (IAVs) have to divert the cellular machinery to ensure sufficient translation of viral mRNAs. To this end, several strategies have been exploited by IAVs, such as host gene shutoff, suppression of host innate immune responses, and selective translation of viral mRNAs. Various IAV proteins are responsible for host gene shutoff, e.g., NS1, PA-X, and RdRp, through inhibition of cellular gene transcription, suppression of cellular RNA processing, degradation of cellular RNAs, and blockage of cellular mRNA export from the nucleus. Host shutoff should suppress the innate immune responses and also increase the translation of viral mRNAs indirectly due to the reduced competition from cellular mRNAs for cellular translational machinery. However, many other mechanisms are also responsible for the suppression of innate immune responses by IAV, such as prevention of the detection of the viral RNAs by the RLRs, inhibition of the activities of proteins involved in signaling events of interferon production, and inhibition of the activities of interferon-stimulated genes, mainly through viral NS1, PB1-F2, and PA-X proteins. IAV mRNAs may be selectively translated in favor of cellular mRNAs through interacting with viral and/or cellular proteins, such as NS1, PABPI, and/or IFIT2, in the 5'-UTR of viral mRNAs. This review briefly summarizes the strategies utilized by IAVs to ensure sufficient translation of viral mRNAs focusing on recent developments.
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11
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Analysis of Expression Pattern of snoRNAs in Human Cells A549 Infected by Influenza A Virus. Int J Mol Sci 2022; 23:ijms232213666. [PMID: 36430145 PMCID: PMC9696202 DOI: 10.3390/ijms232213666] [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: 08/15/2022] [Revised: 10/20/2022] [Accepted: 10/29/2022] [Indexed: 11/09/2022] Open
Abstract
Small nucleolar RNAs (snoRNAs) are a highly expressed class of non-coding RNAs known for their role in guiding post-transcriptional modifications of ribosomal RNAs and small nuclear RNAs. Emerging studies suggest that snoRNAs are also implicated in regulating other vital cellular processes, such as pre-mRNA splicing and 3'-processing of mRNAs, and in the development of cancer and viral infections. There is an emerging body of evidence for specific snoRNA's involvement in the optimal replication of RNA viruses. In order to investigate the expression pattern of snoRNAs during influenza A viral infection, we performed RNA sequencing analysis of the A549 human cell line infected by influenza virus A/Puerto Rico/8/1934 (H1N1). We identified 66 that were upregulated and 55 that were downregulated in response to influenza A virus infection. The increased expression of most C/D-box snoRNAs was associated with elevated levels of 5'- and 3'-short RNAs derived from this snoRNA. Analysis of the poly(A)+ RNA sequencing data indicated that most of the differentially expressed snoRNAs synthesis was not correlated with the corresponding host genes expression. Furthermore, influenza A viral infection led to an imbalance in the expression of genes responsible for C/D small nucleolar ribonucleoprotein particles' biogenesis. In summary, our results indicate that the expression pattern of snoRNAs in A549 cells is significantly altered during influenza A viral infection.
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12
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Lutz M, Schmierer J, Takimoto T. Host adaptive mutations in the 2009 H1N1 pandemic influenza A virus PA gene regulate translation efficiency of viral mRNAs via GRSF1. Commun Biol 2022; 5:1102. [PMID: 36253464 PMCID: PMC9576711 DOI: 10.1038/s42003-022-04082-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/06/2022] [Indexed: 11/08/2022] Open
Abstract
Avian species are the major natural reservoir from which pandemic influenza A viruses can be introduced to humans. Avian influenza A virus genes, including the three viral polymerase genes, PA, PB1 and PB2, require host-adaptive mutations to allow for viral replication and transmission in humans. Previously, PA from the 2009 pH1N1 viral polymerase was found to harbor host-adaptive mutations leading to enhanced viral polymerase activity. By quantifying translation and mRNA transcription, we found that the 2009 pH1N1 PA, and the associated host-adaptive mutations, led to greater translation efficiency. This was due to enhanced cytosolic accumulation of viral mRNA, which was dependent on the host RNA binding protein GRSF1. Mutations to the GRSF1 binding site in viral mRNA, as well as GRSF1 knockdown, reduced cytosolic accumulation and translation efficiency of viral mRNAs. This study identifies a previously unrecognized mechanism by which host-adaptive mutations in PA regulate viral replication and host adaptation. Importantly, these results provide greater insight into the host adaptation process of IAVs and reveal the importance of GRSF1 in the lifecycle of IAV.
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Affiliation(s)
- Michael Lutz
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Jordana Schmierer
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Toru Takimoto
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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13
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Xu M, Risse J, Kormelink R. Cap-snatching as a possible contributor to photosynthesis shut-off. J Gen Virol 2022; 103. [PMID: 35947091 DOI: 10.1099/jgv.0.001763] [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
Cap-snatching is a mechanism applied by segmented, negative strand (-) RNA viruses (NSVs) to initiate genome transcription. So far, the cap donor source of cytoplasmic-replicating NSVs has remained elusive. Recently, studies pointed to processing body (P body, PB) as the potential source for providing capped RNAs but conclusive evidence is still lacking. To attempt identifying these sources, here the 5' non-viral leader sequences of Tomato spotted wilt virus (TSWV) N mRNAs were analysed by high-throughput sequencing (HTS) from plants subjected to normal and heat-stress conditions, and subsequently mapped on host donor transcripts. The majority of non-viral heterogenous, host-derived leader sequences ranged in size between ~10-20 nt and contained A or AG residues at the cleavage site and the presence of certain sequence motifs. Mapping the capped-leader sequences to the 5' UTR region of genes encoded by the Nicotiana tabacum genome, identified 348 donor genes and which were specifically enriched in cellular photosynthesis pathway. Nineteen of those were clearly expressed differentially at normal condition versus heat-stress conditions. Although the results did not point towards snatching of capped-RNA leader sequences from certain cytoplasmic RNA granules in particular, they indicated photosynthesis downregulation (and development of disease symptoms) partially result from cap-snatching.
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Affiliation(s)
- Min Xu
- Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Judith Risse
- Laboratory of Bioinformatics, Department of Plant Sciences, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
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14
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de Rozières CM, Pequeno A, Shahabi S, Lucas TM, Godula K, Ghosh G, Joseph S. PABP1 Drives the Selective Translation of Influenza A Virus mRNA. J Mol Biol 2022; 434:167460. [PMID: 35074482 PMCID: PMC8897273 DOI: 10.1016/j.jmb.2022.167460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/22/2021] [Accepted: 01/13/2022] [Indexed: 11/26/2022]
Abstract
Influenza A virus (IAV) is a human-infecting pathogen with a history of causing seasonal epidemics and on several occasions worldwide pandemics. Infection by IAV causes a dramatic decrease in host mRNA translation, whereas viral mRNAs are efficiently translated. The IAV mRNAs have a highly conserved 5'-untranslated region (5'UTR) that is rich in adenosine residues. We show that the human polyadenylate binding protein 1 (PABP1) binds to the 5'UTR of the viral mRNAs. The interaction of PABP1 with the viral 5'UTR makes the translation of viral mRNAs more resistant to canonical cap-dependent translation inhibition than model mRNAs. Additionally, PABP1 bound to the viral 5'UTR can recruit eIF4G in an eIF4E-independent manner. These results indicate that PABP1 bound to the viral 5'UTR may promote eIF4E-independent translation initiation.
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Affiliation(s)
- Cyrus M de Rozières
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Alberto Pequeno
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Shandy Shahabi
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Taryn M Lucas
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Kamil Godula
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA
| | - Simpson Joseph
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0314, USA.
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15
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Migration of Influenza Virus Nucleoprotein into the Nucleolus Is Essential for Ribonucleoprotein Complex Formation. mBio 2022. [PMCID: PMC8725578 DOI: 10.1128/mbio.03315-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Influenza A virus double-helical ribonucleoprotein complex (RNP) performs transcription and replication of viral genomic RNA (vRNA). Although RNP formation occurs in the nuclei of virus-infected cells, the nuclear domains involved in this process remain unclear. Here, we show that the nucleolus is an essential site for functional RNP formation. Viral nucleoprotein (NP), a major RNP component, temporarily localized to the nucleoli of virus-infected cells. Mutations in a nucleolar localization signal (NoLS) on NP abolished double-helical RNP formation, resulting in a loss of viral RNA synthesis ability, whereas ectopic fusion of the NoLS enabled the NP mutant to form functional double-helical RNPs. Furthermore, nucleolar disruption of virus-infected cells inhibited NP assembly into double-helical RNPs, resulting in decreased viral RNA synthesis. Collectively, our findings demonstrate that NP migration into the nucleolus is a critical step for functional RNP formation, showing the importance of the nucleolus in the influenza virus life cycle.
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16
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Mapping inhibitory sites on the RNA polymerase of the 1918 pandemic influenza virus using nanobodies. Nat Commun 2022; 13:251. [PMID: 35017564 PMCID: PMC8752864 DOI: 10.1038/s41467-021-27950-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022] Open
Abstract
Influenza A viruses cause seasonal epidemics and global pandemics, representing a considerable burden to healthcare systems. Central to the replication cycle of influenza viruses is the viral RNA-dependent RNA polymerase which transcribes and replicates the viral RNA genome. The polymerase undergoes conformational rearrangements and interacts with viral and host proteins to perform these functions. Here we determine the structure of the 1918 influenza virus polymerase in transcriptase and replicase conformations using cryo-electron microscopy (cryo-EM). We then structurally and functionally characterise the binding of single-domain nanobodies to the polymerase of the 1918 pandemic influenza virus. Combining these functional and structural data we identify five sites on the polymerase which are sensitive to inhibition by nanobodies. We propose that the binding of nanobodies at these sites either prevents the polymerase from assuming particular functional conformations or interactions with viral or host factors. The polymerase is highly conserved across the influenza A subtypes, suggesting these sites as effective targets for potential influenza antiviral development. Influenza viruses carry their own RNAdependent RNA-polymerase that is highly conserved and a promising anti-viral target. Combining functional and structural data, Keown et al. characterise the inhibitory effect of nanobodies on 1918 pandemic H1N1 influenza strain polymerase complex and identify sensitive sites interfering with polymerase activity in vitro.
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17
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Pyle JD, Whelan SPJ, Bloyet LM. Structure and function of negative-strand RNA virus polymerase complexes. Enzymes 2021; 50:21-78. [PMID: 34861938 DOI: 10.1016/bs.enz.2021.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Viruses with negative-strand RNA genomes (NSVs) include many highly pathogenic and economically devastating disease-causing agents of humans, livestock, and plants-highlighted by recent Ebola and measles virus epidemics, and continuously circulating influenza virus. Because of their protein-coding orientation, NSVs face unique challenges for efficient gene expression and genome replication. To overcome these barriers, NSVs deliver a large and multifunctional RNA-dependent RNA polymerase into infected host cells. NSV-encoded polymerases contain all the enzymatic activities required for transcription and replication of their genome-including RNA synthesis and mRNA capping. Here, we review the structures and functions of NSV polymerases with a focus on key domains responsible for viral replication and gene expression. We highlight shared and unique features among polymerases of NSVs from the Mononegavirales, Bunyavirales, and Articulavirales orders.
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Affiliation(s)
- Jesse D Pyle
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States; Ph.D. Program in Virology, Harvard Medical School, Boston, MA, United States
| | - Sean P J Whelan
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States.
| | - Louis-Marie Bloyet
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, United States.
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18
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Tejus A, Mathur A, Pradhan S, Malik S, Salmani MF. Drug update - Baloxavir marboxil: Latest entrant into the arena of pharmacotherapy of influenza. Med J Armed Forces India 2021; 78:125-130. [PMID: 35463549 PMCID: PMC9023778 DOI: 10.1016/j.mjafi.2021.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 09/21/2021] [Indexed: 11/17/2022] Open
Abstract
Influenza is a frequent cause of clinically significant human disease, with seasonal epidemics and occasional pandemics. Uncomplicated influenza in healthy individuals is managed symptomatically. Vaccination against influenza plays a vital role in the control of infection in humans. The currently available antivirals include adamantanes, neuraminidase inhibitors, and ribavirin. Baloxavir marboxil, the prodrug of baloxavir, is the latest addition to the family of anti-influenza drugs, and it received US-FDA approval on October 24, 2018. Baloxavir acts through a novel mechanism of inhibiting Cap-dependent endonuclease (CEN), the vital step in the transcription of viral RNA, and prevents further spread of the virus.
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Affiliation(s)
- A. Tejus
- Classified Specialist (Pharmacology), Medical Officer, HQ IMTRAT, C/o 99 APO, India
- Corresponding author.
| | | | - Sapna Pradhan
- Professor (Pharmacology), Army College of Medical Sciences, Delhi Cantt, India
| | - Salma Malik
- Demonstrator (Pharmacology), Army College of Medical Sciences, Delhi Cantt, India
| | - Md Fadil Salmani
- Demonstrator (Pharmacology), Army College of Medical Sciences, Delhi Cantt, India
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19
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Staller E, Barclay WS. Host Cell Factors That Interact with Influenza Virus Ribonucleoproteins. Cold Spring Harb Perspect Med 2021; 11:a038307. [PMID: 32988980 PMCID: PMC8559542 DOI: 10.1101/cshperspect.a038307] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Influenza viruses hijack host cell factors at each stage of the viral life cycle. After host cell entry and endosomal escape, the influenza viral ribonucleoproteins (vRNPs) are released into the cytoplasm where the classical cellular nuclear import pathway is usurped for nuclear translocation of the vRNPs. Transcription takes place inside the nucleus at active host transcription sites, and cellular mRNA export pathways are subverted for export of viral mRNAs. Newly synthesized RNP components cycle back into the nucleus using various cellular nuclear import pathways and host-encoded chaperones. Replication of the negative-sense viral RNA (vRNA) into complementary RNA (cRNA) and back into vRNA requires complex interplay between viral and host factors. Progeny vRNPs assemble at the host chromatin and subsequently exit from the nucleus-processes orchestrated by sets of host and viral proteins. Finally, several host pathways appear to play a role in vRNP trafficking from the nuclear envelope to the plasma membrane for egress.
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Affiliation(s)
- Ecco Staller
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, St. Mary's Campus, London W2 1NY, United Kingdom
| | - Wendy S Barclay
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, St. Mary's Campus, London W2 1NY, United Kingdom
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20
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Iarovaia OV, Ioudinkova ES, Velichko AK, Razin SV. Manipulation of Cellular Processes via Nucleolus Hijaking in the Course of Viral Infection in Mammals. Cells 2021; 10:cells10071597. [PMID: 34202380 PMCID: PMC8303250 DOI: 10.3390/cells10071597] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/16/2022] Open
Abstract
Due to their exceptional simplicity of organization, viruses rely on the resources, molecular mechanisms, macromolecular complexes, regulatory pathways, and functional compartments of the host cell for an effective infection process. The nucleolus plays an important role in the process of interaction between the virus and the infected cell. The interactions of viral proteins and nucleic acids with the nucleolus during the infection process are universal phenomena and have been described for almost all taxonomic groups. During infection, proteins of the nucleolus in association with viral components can be directly used for the processes of replication and transcription of viral nucleic acids and the assembly and transport of viral particles. In the course of a viral infection, the usurpation of the nucleolus functions occurs and the usurpation is accompanied by profound changes in ribosome biogenesis. Recent studies have demonstrated that the nucleolus is a multifunctional and dynamic compartment. In addition to the biogenesis of ribosomes, it is involved in regulating the cell cycle and apoptosis, responding to cellular stress, repairing DNA, and transcribing RNA polymerase II-dependent genes. A viral infection can be accompanied by targeted transport of viral proteins to the nucleolus, massive release of resident proteins of the nucleolus into the nucleoplasm and cytoplasm, the movement of non-nucleolar proteins into the nucleolar compartment, and the temporary localization of viral nucleic acids in the nucleolus. The interaction of viral and nucleolar proteins interferes with canonical and non-canonical functions of the nucleolus and results in a change in the physiology of the host cell: cell cycle arrest, intensification or arrest of ribosome biogenesis, induction or inhibition of apoptosis, and the modification of signaling cascades involved in the stress response. The nucleolus is, therefore, an important target during viral infection. In this review, we discuss the functional impact of viral proteins and nucleic acid interaction with the nucleolus during infection.
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21
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Unconventional viral gene expression mechanisms as therapeutic targets. Nature 2021; 593:362-371. [PMID: 34012080 DOI: 10.1038/s41586-021-03511-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 03/22/2021] [Indexed: 12/14/2022]
Abstract
Unlike the human genome that comprises mostly noncoding and regulatory sequences, viruses have evolved under the constraints of maintaining a small genome size while expanding the efficiency of their coding and regulatory sequences. As a result, viruses use strategies of transcription and translation in which one or more of the steps in the conventional gene-protein production line are altered. These alternative strategies of viral gene expression (also known as gene recoding) can be uniquely brought about by dedicated viral enzymes or by co-opting host factors (known as host dependencies). Targeting these unique enzymatic activities and host factors exposes vulnerabilities of a virus and provides a paradigm for the design of novel antiviral therapies. In this Review, we describe the types and mechanisms of unconventional gene and protein expression in viruses, and provide a perspective on how future basic mechanistic work could inform translational efforts that are aimed at viral eradication.
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22
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Krischuns T, Lukarska M, Naffakh N, Cusack S. Influenza Virus RNA-Dependent RNA Polymerase and the Host Transcriptional Apparatus. Annu Rev Biochem 2021; 90:321-348. [PMID: 33770447 DOI: 10.1146/annurev-biochem-072820-100645] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Influenza virus RNA-dependent RNA polymerase (FluPol) transcribes the viral RNA genome in the infected cell nucleus. In the 1970s, researchers showed that viral transcription depends on host RNA polymerase II (RNAP II) activity and subsequently that FluPol snatches capped oligomers from nascent RNAP II transcripts to prime its own transcription. Exactly how this occurs remains elusive. Here, we review recent advances in the mechanistic understanding of FluPol transcription and early events in RNAP II transcription that are relevant to cap-snatching. We describe the known direct interactions between FluPol and the RNAP II C-terminal domain and summarize the transcription-related host factors that have been found to interact with FluPol. We also discuss open questions regarding how FluPol may be targeted to actively transcribing RNAP II and the exact context and timing of cap-snatching, which is presumed to occur after cap completion but before the cap is sequestered by the nuclear cap-binding complex.
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Affiliation(s)
- Tim Krischuns
- Unité Biologie des ARN et Virus Influenza, Département de Virologie, Institut Pasteur, CNRS UMR 3569, F-75015 Paris, France; ,
| | - Maria Lukarska
- European Molecular Biology Laboratory, 38042 Grenoble CEDEX 9, France; .,Current affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA;
| | - Nadia Naffakh
- Unité Biologie des ARN et Virus Influenza, Département de Virologie, Institut Pasteur, CNRS UMR 3569, F-75015 Paris, France; ,
| | - Stephen Cusack
- European Molecular Biology Laboratory, 38042 Grenoble CEDEX 9, France;
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23
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Gultyaev AP, Spronken MI, Funk M, Fouchier RAM, Richard M. Insertions of codons encoding basic amino acids in H7 hemagglutinins of influenza A viruses occur by recombination with RNA at hotspots near snoRNA binding sites. RNA (NEW YORK, N.Y.) 2021; 27:123-132. [PMID: 33188057 PMCID: PMC7812872 DOI: 10.1261/rna.077495.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
The presence of multiple basic amino acids in the protease cleavage site of the hemagglutinin (HA) protein is the main molecular determinant of virulence of highly pathogenic avian influenza (HPAI) viruses. Recombination of HA RNA with other RNA molecules of host or virus origin is a dominant mechanism of multibasic cleavage site (MBCS) acquisition for H7 subtype HA. Using alignments of HA RNA sequences from documented cases of MBCS insertion due to recombination, we show that such recombination with host RNAs is most likely to occur at particular hotspots in ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), and viral RNAs. The locations of these hotspots in highly abundant RNAs indicate that RNA recombination is facilitated by the binding of small nucleolar RNA (snoRNA) near the recombination points.
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MESH Headings
- Amino Acids, Basic/genetics
- Amino Acids, Basic/metabolism
- Animals
- Base Pairing
- Base Sequence
- Chickens/virology
- Codon
- Gene Expression Regulation
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/metabolism
- Host-Pathogen Interactions/genetics
- Humans
- Influenza A virus/genetics
- Influenza A virus/metabolism
- Influenza A virus/pathogenicity
- Influenza in Birds/virology
- Influenza, Human/virology
- Mutagenesis, Insertional
- RNA, Small Nucleolar/chemistry
- RNA, Small Nucleolar/genetics
- RNA, Small Nucleolar/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Recombination, Genetic
- Sequence Alignment
- Virulence
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Affiliation(s)
- Alexander P Gultyaev
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
- Group Imaging and Bioinformatics, Leiden Institute of Advanced Computer Science (LIACS), Leiden University, 2300 RA Leiden, the Netherlands
| | - Monique I Spronken
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Mathis Funk
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Ron A M Fouchier
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Mathilde Richard
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
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24
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Sacco MT, Horner SM. Flipping the script: viral capitalization of RNA modifications. Brief Funct Genomics 2021; 20:86-93. [PMID: 33401298 DOI: 10.1093/bfgp/elaa025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023] Open
Abstract
RNA encoded by RNA viruses is highly regulated so that it can function in multiple roles during the viral life cycle. These roles include serving as the mRNA template for translation or the genetic material for replication as well as being packaged into progeny virions. RNA modifications provide an emerging regulatory dimension to the RNA of viruses. Modification of the viral RNA can increase the functional genomic capacity of the RNA viruses without the need to encode and translate additional genes. Further, RNA modifications can facilitate interactions with host or viral RNA-binding proteins that promote replication or can prevent interactions with antiviral RNA-binding proteins. The mechanisms by which RNA viruses facilitate modification of their RNA are diverse. In this review, we discuss some of these mechanisms, including exploring the unknown mechanism by which the RNA of viruses that replicate in the cytoplasm could acquire the RNA modification N6-methyladenosine.
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25
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Dai H, Gu W. Small RNA Plays Important Roles in Virus-Host Interactions. Viruses 2020; 12:E1271. [PMID: 33171824 PMCID: PMC7695165 DOI: 10.3390/v12111271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/30/2020] [Accepted: 11/05/2020] [Indexed: 12/12/2022] Open
Abstract
Non-coding small RNAs play important roles in virus-host interactions. For hosts, small RNAs can serve as sensors in antiviral pathways including RNAi and CRISPR; for viruses, small RNAs can be involved in viral transcription and replication. This paper covers several recent discoveries on small RNA mediated virus-host interactions, and focuses on influenza virus cap-snatching and a few important virus sensors including PIR-1, RIG-I like protein DRH-1 and piRNAs. The paper also discusses recent advances in mammalian antiviral RNAi.
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Affiliation(s)
| | - Weifeng Gu
- Department of Molecular, Cell and Systems Biology, University of California, Riverside 900 University Avenue, Riverside, CA 92521, USA;
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26
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Arif M, Atta S, Bashir MA, Hussain A, Khan MI, Farooq S, Hannan A, Islam SU, Umar UUD, Khan M, Lin W, Hashem M, Alamri S, Wu Z. Molecular characterization and RSV Co-infection of Nicotiana benthamiana with three distinct begomoviruses. Methods 2020; 183:43-49. [PMID: 31759050 DOI: 10.1016/j.ymeth.2019.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/10/2019] [Accepted: 11/16/2019] [Indexed: 12/31/2022] Open
Abstract
Geminiviruses constitute a family of plant viruses with characteristic twinned quasi-icosahedral virions and a small circular DNA genome. Geminiviruses, especially begomoviruses, cause substantial economic losses in tropical and subtropical regions globally. Geminiviruses use the host's transcriptional mechanisms to synthesize their mRNAs. They are considered as an attractive model to understand the transcription mechanism of their host plants. Experiments were conducted to identify transcriptional start sites (TSSs) of the three begomoviruses, i.e., Cotton leaf curl Multan virus (CLCuMuV), Corchorus yellow vein virus (CoYVV), and Ramie mosaic virus (RamV). We first rub-inoculated Rice stripe tenuivirus (RSV), a segmented negative-sense RNA virus that uses cap-snatching to produce capped viral mRNAs, into N. benthamiana. After the inoculation, RSV-infected N. benthamiana were super-infected by CoYVV, CLCuMuV, or RamV, respectively. The capped-RNA leaders snatched by RSV were obtained by determining the 5'-ends of RSV mRNA with high throughput sequencing. Afterwards, snatched capped-RNA leaders of RSV were mapped onto the genome of each begomovirus and those matching the begomoviral genome were considered to come from the 5' ends of assumed begomoviral mRNAs. In this way, TSSs of begomoviruses were obtained. After mapping these TSSs onto the genome of the respective begomovirus, it was found very commonly that a begomovirus can use many different TSSs to transcribe the same gene, producing many different mRNA isoforms containing the corresponding open reading frames (ORFs).
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Affiliation(s)
- Muhammad Arif
- Fujian Province Key Laboratory of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan; Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
| | - Sagheer Atta
- Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Muhammad Amjad Bashir
- Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Ansar Hussain
- Department of Plant Breeding and Genetics, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Muhammad Ifnan Khan
- Department of Plant Breeding and Genetics, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Shahid Farooq
- Department of Plant Protection, Faculty of Agriculture, Harran University, Sanliurfa 63200, Turkey
| | - Abdul Hannan
- Department of Botany, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Saif Ul Islam
- Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ummad Ud Din Umar
- Department of Plant Pathology, Bahauddin Zakariya University, Multan, Punjab 60800, Pakistan
| | - Mehran Khan
- Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Punjab 32200, Pakistan
| | - Wenzhong Lin
- Fujian Province Key Laboratory of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Mohamed Hashem
- King Khalid University, College of Science, Department of Biology, Abha 61413, Saudi Arabia; Assiut University, Faculty of Science, Botany and Microbiology Department, Assiut, Egypt
| | - Saad Alamri
- King Khalid University, College of Science, Department of Biology, Abha 61413, Saudi Arabia; Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, Saudi Arabia
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; Department of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
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27
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Li L, Dai H, Nguyen AP, Hai R, Gu W. Influenza A virus utilizes noncanonical cap-snatching to diversify its mRNA/ncRNA. RNA (NEW YORK, N.Y.) 2020; 26:1170-1183. [PMID: 32444459 PMCID: PMC7430677 DOI: 10.1261/rna.073866.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
Influenza A virus (IAV) utilizes cap-snatching to obtain host capped small RNAs for priming viral mRNA synthesis, generating capped hybrid mRNAs for translation. Previous studies have been focusing on canonical cap-snatching, which occurs at the very 5' end of viral mRNAs. Here we discovered noncanonical cap-snatching, which generates capped hybrid mRNAs/noncoding RNAs mapped to the region ∼300 nucleotides (nt) upstream of each mRNA 3' end, and to the 5' region, primarily starting at the second nt, of each virion RNAs (vRNA). Like canonical cap-snatching, noncanonical cap-snatching utilizes a base-pairing between the last nt G of host capped RNAs and a nt C of template RNAs to prime RNA synthesis. However, the nt upstream of this template C is usually A/U rather than just U; prime-realignment occurs less frequently. We also demonstrate that IAV can snatch capped IAV RNAs in addition to host RNAs. Noncanonical cap-snatching likely generates novel mRNAs with start AUG encoded in viral or host RNAs. These findings expand our understanding of cap-snatching mechanisms and suggest that IAV may utilize noncanonical cap-snatching to diversify its mRNAs/ncRNAs.
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Affiliation(s)
- Lichao Li
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, California 92521, USA
| | - Hui Dai
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, California 92521, USA
| | - An-Phong Nguyen
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, California 92521, USA
| | - Rong Hai
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521, USA
| | - Weifeng Gu
- Department of Molecular, Cell, and Systems Biology, University of California, Riverside, California 92521, USA
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28
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Dai H, Gu W. Strategies and Best Practice in Cloning Small RNAs. GENE TECHNOLOGY 2020; 9:151. [PMID: 32953938 PMCID: PMC7500658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
High-throughput sequencing has become a standard and powerful tool for analyzing nucleic acids primarily due to its sensitivity and convenience. Small RNAs play important roles in regulating cellular and viral genes. The conventional methods for small RNA analyses are tedious and often lack accuracy, specificity and sensitivity for many small RNA species. Therefore, high-throughput sequencing becomes an indispensable tool for analyzing small RNAs. However, it is challenging to generate a reliable and representative small RNA library for high-throughput sequencing since small RNAs are usually expressed at extremely low levels and often contain modifications which affect library construction, usually causing biased readouts. This review compares various strategies for generating small RNA libraries of high quality and reliability, and provides recommendations on best practice in preparing high-throughput sequencing RNA libraries.
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29
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Ho JSY, Angel M, Ma Y, Sloan E, Wang G, Martinez-Romero C, Alenquer M, Roudko V, Chung L, Zheng S, Chang M, Fstkchyan Y, Clohisey S, Dinan AM, Gibbs J, Gifford R, Shen R, Gu Q, Irigoyen N, Campisi L, Huang C, Zhao N, Jones JD, van Knippenberg I, Zhu Z, Moshkina N, Meyer L, Noel J, Peralta Z, Rezelj V, Kaake R, Rosenberg B, Wang B, Wei J, Paessler S, Wise HM, Johnson J, Vannini A, Amorim MJ, Baillie JK, Miraldi ER, Benner C, Brierley I, Digard P, Łuksza M, Firth AE, Krogan N, Greenbaum BD, MacLeod MK, van Bakel H, Garcìa-Sastre A, Yewdell JW, Hutchinson E, Marazzi I. Hybrid Gene Origination Creates Human-Virus Chimeric Proteins during Infection. Cell 2020; 181:1502-1517.e23. [PMID: 32559462 PMCID: PMC7323901 DOI: 10.1016/j.cell.2020.05.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 02/26/2020] [Accepted: 05/18/2020] [Indexed: 01/12/2023]
Abstract
RNA viruses are a major human health threat. The life cycles of many highly pathogenic RNA viruses like influenza A virus (IAV) and Lassa virus depends on host mRNA, because viral polymerases cleave 5'-m7G-capped host transcripts to prime viral mRNA synthesis ("cap-snatching"). We hypothesized that start codons within cap-snatched host transcripts could generate chimeric human-viral mRNAs with coding potential. We report the existence of this mechanism of gene origination, which we named "start-snatching." Depending on the reading frame, start-snatching allows the translation of host and viral "untranslated regions" (UTRs) to create N-terminally extended viral proteins or entirely novel polypeptides by genetic overprinting. We show that both types of chimeric proteins are made in IAV-infected cells, generate T cell responses, and contribute to virulence. Our results indicate that during infection with IAV, and likely a multitude of other human, animal and plant viruses, a host-dependent mechanism allows the genesis of hybrid genes.
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Affiliation(s)
- Jessica Sook Yuin Ho
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Matthew Angel
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Yixuan Ma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Elizabeth Sloan
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Guojun Wang
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Carles Martinez-Romero
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Marta Alenquer
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Vladimir Roudko
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Medicine, Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Liliane Chung
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Simin Zheng
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Max Chang
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Yesai Fstkchyan
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sara Clohisey
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Adam M Dinan
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 0SP, UK
| | - James Gibbs
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Robert Gifford
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Rong Shen
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK
| | - Quan Gu
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Nerea Irigoyen
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 0SP, UK
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Cheng Huang
- Department of Pathology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Joshua D Jones
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 0SP, UK
| | | | - Zeyu Zhu
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Léa Meyer
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Zuleyma Peralta
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Veronica Rezelj
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| | - Robyn Kaake
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Brad Rosenberg
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Bo Wang
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Jiajie Wei
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Slobodan Paessler
- Department of Pathology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Helen M Wise
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Jeffrey Johnson
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK; Fondazione Human Technopole, Structural Biology Research Centre, 20157 Milan, Italy
| | | | - J Kenneth Baillie
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Emily R Miraldi
- Divisions of Immunobiology and Biomedical Informatics, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45257, USA
| | - Christopher Benner
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Ian Brierley
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 0SP, UK
| | - Paul Digard
- The Roslin Institute, University of Edinburgh, Edinburgh EH25 9PS, UK
| | - Marta Łuksza
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 0SP, UK
| | - Nevan Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Benjamin D Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Medicine, Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Megan K MacLeod
- Centre for Immunobiology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, UK
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Adolfo Garcìa-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jonathan W Yewdell
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Edward Hutchinson
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK.
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Comprehensive Characterization of Transcriptional Activity during Influenza A Virus Infection Reveals Biases in Cap-Snatching of Host RNA Sequences. J Virol 2020; 94:JVI.01720-19. [PMID: 32161175 PMCID: PMC7199409 DOI: 10.1128/jvi.01720-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 02/10/2020] [Indexed: 12/22/2022] Open
Abstract
Infection with influenza A virus (IAV) infection is responsible for an estimated 500,000 deaths and up to 5 million cases of severe respiratory illness each year. In this study, we looked at human primary immune cells (macrophages) infected with IAV. Our method allows us to look at both the host and the virus in parallel. We used these data to explore a process known as “cap-snatching,” where IAV snatches a short nucleotide sequence from capped host RNA. This process was believed to be random. We demonstrate biased snatching of numerous host RNAs, including those associated with snRNA transcription, and avoidance of host transcripts encoding host ribosomal proteins, which are required by IAV for replication. We then describe the transcriptional landscape of the host response to IAV, observing new features, including a failure of IAV-treated MDMs to induce feedback inhibitors of inflammation, seen in response to other treatments. Macrophages in the lung detect and respond to influenza A virus (IAV), determining the nature of the immune response. Using terminal-depth cap analysis of gene expression (CAGE), we quantified transcriptional activity of both host and pathogen over a 24-h time course of IAV infection in primary human monocyte-derived macrophages (MDMs). This method allowed us to observe heterogenous host sequences incorporated into IAV mRNA, “snatched” 5′ RNA caps, and corresponding RNA sequences from host RNAs. In order to determine whether cap-snatching is random or exhibits a bias, we systematically compared host sequences incorporated into viral mRNA (“snatched”) against a complete survey of all background host RNA in the same cells, at the same time. Using a computational strategy designed to eliminate sources of bias due to read length, sequencing depth, and multimapping, we were able to quantify overrepresentation of host RNA features among the sequences that were snatched by IAV. We demonstrate biased snatching of numerous host RNAs, particularly small nuclear RNAs (snRNAs), and avoidance of host transcripts encoding host ribosomal proteins, which are required by IAV for replication. We then used a systems approach to describe the transcriptional landscape of the host response to IAV, observing many new features, including a failure of IAV-treated MDMs to induce feedback inhibitors of inflammation, seen in response to other treatments. IMPORTANCE Infection with influenza A virus (IAV) infection is responsible for an estimated 500,000 deaths and up to 5 million cases of severe respiratory illness each year. In this study, we looked at human primary immune cells (macrophages) infected with IAV. Our method allows us to look at both the host and the virus in parallel. We used these data to explore a process known as “cap-snatching,” where IAV snatches a short nucleotide sequence from capped host RNA. This process was believed to be random. We demonstrate biased snatching of numerous host RNAs, including those associated with snRNA transcription, and avoidance of host transcripts encoding host ribosomal proteins, which are required by IAV for replication. We then describe the transcriptional landscape of the host response to IAV, observing new features, including a failure of IAV-treated MDMs to induce feedback inhibitors of inflammation, seen in response to other treatments.
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31
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Lutz MM, Dunagan MM, Kurebayashi Y, Takimoto T. Key Role of the Influenza A Virus PA Gene Segment in the Emergence of Pandemic Viruses. Viruses 2020; 12:v12040365. [PMID: 32224899 PMCID: PMC7232137 DOI: 10.3390/v12040365] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 03/24/2020] [Indexed: 12/18/2022] Open
Abstract
Influenza A viruses (IAVs) are a significant human pathogen that cause seasonal epidemics and occasional pandemics. Avian waterfowl are the natural reservoir of IAVs, but a wide range of species can serve as hosts. Most IAV strains are adapted to one host species and avian strains of IAV replicate poorly in most mammalian hosts. Importantly, IAV polymerases from avian strains function poorly in mammalian cells but host adaptive mutations can restore activity. The 2009 pandemic H1N1 (H1N1pdm09) virus acquired multiple mutations in the PA gene that activated polymerase activity in mammalian cells, even in the absence of previously identified host adaptive mutations in other polymerase genes. These mutations in PA localize within different regions of the protein suggesting multiple mechanisms exist to activate polymerase activity. Additionally, an immunomodulatory protein, PA-X, is expressed from the PA gene segment. PA-X expression is conserved amongst many IAV strains but activity varies between viruses specific for different hosts, suggesting that PA-X also plays a role in host adaptation. Here, we review the role of PA in the emergence of currently circulating H1N1pdm09 viruses and the most recent studies of host adaptive mutations in the PA gene that modulate polymerase activity and PA-X function.
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Affiliation(s)
- Michael M. Lutz
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA (M.M.D.); (Y.K.)
| | - Megan M. Dunagan
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA (M.M.D.); (Y.K.)
| | - Yuki Kurebayashi
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA (M.M.D.); (Y.K.)
- Department of Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka-shi 422-8526, Japan
| | - Toru Takimoto
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA (M.M.D.); (Y.K.)
- Correspondence: ; Tel.: +1-585-273-2856
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32
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Olschewski S, Cusack S, Rosenthal M. The Cap-Snatching Mechanism of Bunyaviruses. Trends Microbiol 2020; 28:293-303. [PMID: 31948728 DOI: 10.1016/j.tim.2019.12.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 11/25/2022]
Abstract
In common with all segmented negative-sense RNA viruses, bunyavirus transcripts contain heterologous sequences at their 5' termini originating from capped host cell RNAs. These heterologous sequences are acquired by a so-called cap-snatching mechanism. Whereas for nuclear replicating influenza virus the source of capped primers as well as the cap-binding and endonuclease activities of the viral polymerase needed for cap snatching have been functionally and structurally well characterized, our knowledge on the expected counterparts of cytoplasmic replicating bunyaviruses is still limited and controversial. This review focuses on the cap-snatching mechanism of bunyaviruses in the light of recent structural and functional data.
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Affiliation(s)
- Silke Olschewski
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, Hamburg, Germany
| | | | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine, Department of Virology, Hamburg, Germany.
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33
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Xu M, Mazur MJ, Tao X, Kormelink R. Cellular RNA Hubs: Friends and Foes of Plant Viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:40-54. [PMID: 31415225 DOI: 10.1094/mpmi-06-19-0161-fi] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
RNA granules are dynamic cellular foci that are widely spread in eukaryotic cells and play essential roles in cell growth and development, and immune and stress responses. Different types of granules can be distinguished, each with a specific function and playing a role in, for example, RNA transcription, modification, processing, decay, translation, and arrest. By means of communication and exchange of (shared) components, they form a large regulatory network in cells. Viruses have been reported to interact with one or more of these either cytoplasmic or nuclear granules, and act either proviral, to enable and support viral infection and facilitate viral movement, or antiviral, protecting or clearing hosts from viral infection. This review describes an overview and recent progress on cytoplasmic and nuclear RNA granules and their interplay with virus infection, first in animal systems and as a prelude to the status and current developments on plant viruses, which have been less well studied on this thus far.
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Affiliation(s)
- Min Xu
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Magdalena J Mazur
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
| | - Xiaorong Tao
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Droevendaalsesteeg 1, 6708PB Wageningen, The Netherlands
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De Vlugt C, Sikora D, Rocheleau L, Pelchat M. Priming and realignment by the influenza a virus RdRp is dependent on the length of the host primers and the extent of base pairing to viral RNA. Virology 2019; 536:91-100. [PMID: 31404845 DOI: 10.1016/j.virol.2019.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 11/25/2022]
Abstract
Initiation of influenza A virus (IAV) transcription depends on RNA primers derived from host RNAs. During this process, some primers are elongated by a few nucleotides, realigned on the viral RNA templates (vRNA), and then used to initiate another round of transcription. Here, we used information on the host primers used by four IAV strains and four mini-replicons to investigate the characteristics of primer undergoing priming and realignment. We report that primers are biased towards this mechanism on the basis of length and RNA duplex stability with the vRNA templates. Priming and realignment results in primers three nucleotides longer, ending in a nucleotide sequence able to base pair with the 3' end of the vRNA template. By acting on primers based on length and sequence compatibility with the 3' end of the vRNA, priming and realignment rescues suboptimal primers, converting them into ones that can efficiently initiate transcription.
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Affiliation(s)
- Corey De Vlugt
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Dorota Sikora
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Lynda Rocheleau
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada.
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Abstract
Influenza viruses are a leading cause of seasonal and pandemic respiratory illness. Influenza is a negative-sense single-stranded RNA virus that encodes its own RNA-dependent RNA polymerase (RdRp) for nucleic acid synthesis. The RdRp catalyzes mRNA synthesis, as well as replication of the virus genome (viral RNA) through a complementary RNA intermediate. Virus propagation requires the generation of these RNA species in a controlled manner while competing heavily with the host cell for resources. Influenza virus appropriates host factors to enhance and regulate RdRp activity at every step of RNA synthesis. This review describes such host factors and summarizes our current understanding of the roles they play in viral synthesis of RNA.
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Affiliation(s)
- Thomas P Peacock
- Department of Medicine, Imperial College London, London W2 1PG, United Kingdom; , , ,
| | - Carol M Sheppard
- Department of Medicine, Imperial College London, London W2 1PG, United Kingdom; , , ,
| | - Ecco Staller
- Department of Medicine, Imperial College London, London W2 1PG, United Kingdom; , , ,
| | - Wendy S Barclay
- Department of Medicine, Imperial College London, London W2 1PG, United Kingdom; , , ,
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36
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Walker AP, Fodor E. Interplay between Influenza Virus and the Host RNA Polymerase II Transcriptional Machinery. Trends Microbiol 2019; 27:398-407. [PMID: 30642766 PMCID: PMC6467242 DOI: 10.1016/j.tim.2018.12.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/30/2018] [Accepted: 12/20/2018] [Indexed: 12/12/2022]
Abstract
The influenza virus RNA-dependent RNA polymerase (RdRP) cleaves the 5' end of nascent capped host RNAs and uses the capped RNA fragment to prime viral transcription in a mechanism called 'cap snatching'. Cap snatching requires an intimate association between influenza RdRP and cellular RNA polymerase II (Pol II), which is the source of nascent capped host RNAs targeted by influenza virus. Recent structural studies have revealed how influenza RdRP binds to Pol II and how this binding promotes the initiation of viral transcription by influenza RdRP. In this review we focus on these recent insights into the mechanism of cap snatching by influenza virus and the impact of cap snatching on host gene expression during influenza virus infection.
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Affiliation(s)
- Alexander P Walker
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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Cross ST, Michalski D, Miller MR, Wilusz J. RNA regulatory processes in RNA virus biology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1536. [PMID: 31034160 PMCID: PMC6697219 DOI: 10.1002/wrna.1536] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/13/2022]
Abstract
Numerous post‐transcriptional RNA processes play a major role in regulating the quantity, quality and diversity of gene expression in the cell. These include RNA processing events such as capping, splicing, polyadenylation and modification, but also aspects such as RNA localization, decay, translation, and non‐coding RNA‐associated regulation. The interface between the transcripts of RNA viruses and the various RNA regulatory processes in the cell, therefore, has high potential to significantly impact virus gene expression, regulation, cytopathology and pathogenesis. Furthermore, understanding RNA biology from the perspective of an RNA virus can shed considerable light on the broad impact of these post‐transcriptional processes in cell biology. Thus the goal of this article is to provide an overview of the richness of cellular RNA biology and how RNA viruses use, usurp and/or avoid the associated machinery to impact the outcome of infection. This article is categorized under:RNA in Disease and Development > RNA in Disease
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Affiliation(s)
- Shaun T Cross
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Daniel Michalski
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Megan R Miller
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
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38
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Liu G, Lu Y, Liu Q, Zhou Y. Inhibition of Ongoing Influenza A Virus Replication Reveals Different Mechanisms of RIG-I Activation. J Virol 2019; 93:e02066-18. [PMID: 30602605 PMCID: PMC6401434 DOI: 10.1128/jvi.02066-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 12/18/2018] [Indexed: 12/13/2022] Open
Abstract
Pattern recognition receptors provide essential nonself immune surveillance within distinct cellular compartments. Retinoic acid-inducible gene I (RIG-I) is one of the primary cytosolic RNA sensors, with an emerging role in the nucleus. It is involved in the spatiotemporal sensing of influenza A virus (IAV) replication, leading to the induction of type I interferons (IFNs). Nonetheless, the physiological viral ligands activating RIG-I during IAV infection remain underexplored. Other than full-length viral genomes, cellular constraints that impede ongoing viral replication likely potentiate an erroneous viral polymerase generating aberrant viral RNA species with RIG-I-activating potential. Here, we investigate the origins of RIG-I-activating viral RNA under two such constraints. Using chemical inhibitors that inhibit continuous viral protein synthesis, we identify the incoming, but not de novo-synthesized, viral defective interfering (DI) genomes contributing to RIG-I activation. In comparison, deprivation of viral nucleoprotein (NP), the key RNA chain elongation factor for the viral polymerase, leads to the production of aberrant viral RNA species activating RIG-I; however, their nature is likely to be distinct from that of DI RNA. Moreover, RIG-I activation in response to NP deprivation is not adversely affected by expression of the nuclear export protein (NEP), which diminishes the generation of a major subset of aberrant viral RNA but facilitates the accumulation of small viral RNA (svRNA). Overall, our results indicate the existence of fundamentally different mechanisms of RIG-I activation under cellular constraints that impede ongoing IAV replication.IMPORTANCE The induction of an IFN response by IAV is mainly mediated by the RNA sensor RIG-I. The physiological RIG-I ligands produced during IAV infection are not fully elucidated. Cellular constraints leading to the inhibition of ongoing viral replication likely potentiate an erroneous viral polymerase producing aberrant viral RNA species activating RIG-I. Here, we demonstrate that RIG-I activation during chemical inhibition of continuous viral protein synthesis is attributable to the incoming DI genomes. Erroneous viral replication driven by NP deprivation promotes the generation of RIG-I-activating aberrant viral RNA, but their nature is likely to be distinct from that of DI RNA. Our results thus reveal distinct mechanisms of RIG-I activation by IAV under cellular constraints impeding ongoing viral replication. A better understanding of RIG-I sensing of IAV infection provides insight into the development of novel interventions to combat influenza virus infection.
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Affiliation(s)
- GuanQun Liu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Vaccinology and Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yao Lu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Qiang Liu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Vaccinology and Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yan Zhou
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Vaccinology and Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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39
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Stamm S, Lodmell JS. C/D box snoRNAs in viral infections: RNA viruses use old dogs for new tricks. Noncoding RNA Res 2019; 4:46-53. [PMID: 31193534 PMCID: PMC6533054 DOI: 10.1016/j.ncrna.2019.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/27/2019] [Accepted: 02/13/2019] [Indexed: 12/17/2022] Open
Abstract
C/D box snoRNAs (SNORDs) are a highly expressed class of non-coding RNAs. Besides their well-established role in rRNA modification, C/D box snoRNAs form protein complexes devoid of fibrillarin and regulate pre-mRNA splicing and polyadenylation of numerous genes. There is an emerging body of evidence for functional interactions between RNA viruses and C/D box snoRNAs. The infectivity of some RNA viruses depends on enzymatically active fibrillarin, and many RNA viral proteins associate with nucleolin or nucleophosmin, suggesting that viruses benefit from their cytosolic accumulation. These interactions are likely reflected by morphological changes in the nucleolus, often leading to relocalization of nucleolar proteins and ncRNAs to the cytosol that are a characteristic feature of viral infections. Knock-down studies have also shown that RNA viruses need specific C/D box snoRNAs for optimal replication, suggesting that RNA viruses benefit from gene expression programs regulated by SNORDs, or that viruses have evolved “new” uses for these humble ncRNAs to advance their prospects during infection.
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Affiliation(s)
- Stefan Stamm
- University of Kentucky, Molecular and Cellular Biochemistry, 741 South Limestone, Lexington, KY 40536, USA
| | - J Stephen Lodmell
- Division of Biological Sciences and Center for Biomolecular Structure and Dynamics, The University of Montana, Missoula, MT, USA
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40
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Arif M, Islam SU, Adnan M, Anwar M, Ali H, Wu Z. Recent progress on gene silencing/suppression by virus-derived small interfering RNAs in rice viruses especially Rice grassy stunt virus. Microb Pathog 2018; 125:210-218. [DOI: 10.1016/j.micpath.2018.09.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/08/2018] [Accepted: 09/11/2018] [Indexed: 12/16/2022]
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De Vlugt C, Sikora D, Pelchat M. Insight into Influenza: A Virus Cap-Snatching. Viruses 2018; 10:v10110641. [PMID: 30453478 PMCID: PMC6266781 DOI: 10.3390/v10110641] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/12/2018] [Accepted: 11/15/2018] [Indexed: 12/27/2022] Open
Abstract
The influenza A virus (IAV) genome consists of eight single-stranded RNA segments. Each segment is associated with a protein complex, with the 3′ and 5′ ends bound to the RNA-dependent RNA polymerase (RdRp) and the remainder associated with the viral nucleoprotein. During transcription of viral mRNA, this ribonucleoprotein complex steals short, 5′-capped transcripts produced by the cellular DNA dependent RNA polymerase II (RNAPII) and uses them to prime transcription of viral mRNA. Here, we review the current knowledge on the process of IAV cap-snatching and suggest a requirement for RNAPII promoter-proximal pausing for efficient IAV mRNA transcription.
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Affiliation(s)
- Corey De Vlugt
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
| | - Dorota Sikora
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
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Littauer EQ, Skountzou I. Hormonal Regulation of Physiology, Innate Immunity and Antibody Response to H1N1 Influenza Virus Infection During Pregnancy. Front Immunol 2018; 9:2455. [PMID: 30420854 PMCID: PMC6215819 DOI: 10.3389/fimmu.2018.02455] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/04/2018] [Indexed: 12/13/2022] Open
Abstract
In 2009, the H1N1 swine flu pandemic highlighted the vulnerability of pregnant women to influenza viral infection. Pregnant women infected with influenza A virus were at increased risk of hospitalization and severe acute respiratory distress syndrome (ARDS), which is associated with high mortality, while their newborns had an increased risk of pre-term birth or low birth weight. Pregnant women have a unique immunological profile modulated by the sex hormones required to maintain pregnancy, namely progesterone and estrogens. The role of these hormones in coordinating maternal immunotolerance in uterine tissue and cellular subsets has been well researched; however, these hormones have wide-ranging effects outside the uterus in modulating the immune response to disease. In this review, we compile research findings in the clinic and in animal models that elaborate on the unique features of H1N1 influenza A viral pathogenesis during pregnancy, the crosstalk between innate immune signaling and hormonal regulation during pregnancy, and the role of pregnancy hormones in modulating cellular responses to influenza A viral infection at mid-gestation. We highlight the ways in which lung architecture and function is stressed by pregnancy, increasing baseline inflammation prior to infection. We demonstrate that infection disrupts progesterone production and upregulates inflammatory mediators, such as cyclooxygenase-2 (COX-2) and prostaglandins, resulting in pre-term labor and spontaneous abortions. Lastly, we profile the ways in which pregnancy alters innate and adaptive cellular immune responses to H1N1 influenza viral infection, and the ways in which these protect fetal development at the expense of effective long-term immune memory. Thus, we highlight advancements in the field of reproductive immunology in response to viral infection and illustrate how that knowledge might be used to develop more effective post-infection therapies and vaccination strategies.
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Affiliation(s)
- Elizabeth Q Littauer
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, United States
| | - Ioanna Skountzou
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, United States.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, United States
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Levene RE, Gaglia MM. Host Shutoff in Influenza A Virus: Many Means to an End. Viruses 2018; 10:E475. [PMID: 30189604 PMCID: PMC6165434 DOI: 10.3390/v10090475] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 08/31/2018] [Accepted: 09/01/2018] [Indexed: 12/21/2022] Open
Abstract
Influenza A virus carries few of its own proteins, but uses them effectively to take control of the infected cells and avoid immune responses. Over the years, host shutoff, the widespread down-regulation of host gene expression, has emerged as a key process that contributes to cellular takeover in infected cells. Interestingly, multiple mechanisms of host shutoff have been described in influenza A virus, involving changes in translation, RNA synthesis and stability. Several viral proteins, notably the non-structural protein NS1, the RNA-dependent RNA polymerase and the endoribonuclease PA-X have been implicated in host shutoff. This multitude of host shutoff mechanisms indicates that host shutoff is an important component of the influenza A virus replication cycle. Here we review the various mechanisms of host shutoff in influenza A virus and the evidence that they contribute to immune evasion and/or viral replication. We also discuss what the purpose of having multiple mechanisms may be.
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Affiliation(s)
- Rachel Emily Levene
- Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA 02111, USA.
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA.
| | - Marta Maria Gaglia
- Graduate Program in Molecular Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA 02111, USA.
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA.
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44
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Kumar R, Khandelwal N, Thachamvally R, Tripathi BN, Barua S, Kashyap SK, Maherchandani S, Kumar N. Role of MAPK/MNK1 signaling in virus replication. Virus Res 2018; 253:48-61. [PMID: 29864503 PMCID: PMC7114592 DOI: 10.1016/j.virusres.2018.05.028] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/16/2018] [Accepted: 05/31/2018] [Indexed: 12/23/2022]
Abstract
Viruses are known to exploit cellular signaling pathways. MAPK is a major cell signaling pathway activated by diverse group of viruses. MNK1 regulates both cap-dependent and IRES-mediated mRNA translation. This review discuss the role of MAPK, particularly the role of MNK1 in virus replication.
Viruses are obligate intracellular parasites; they heavily depend on the host cell machinery to effectively replicate and produce new progeny virus particles. Following viral infection, diverse cell signaling pathways are initiated by the cells, with the major goal of establishing an antiviral state. However, viruses have been shown to exploit cellular signaling pathways for their own effective replication. Genome-wide siRNA screens have also identified numerous host factors that either support (proviral) or inhibit (antiviral) virus replication. Some of the host factors might be dispensable for the host but may be critical for virus replication; therefore such cellular factors may serve as targets for development of antiviral therapeutics. Mitogen activated protein kinase (MAPK) is a major cell signaling pathway that is known to be activated by diverse group of viruses. MAPK interacting kinase 1 (MNK1) has been shown to regulate both cap-dependent and internal ribosomal entry sites (IRES)-mediated mRNA translation. In this review we have discuss the role of MAPK in virus replication, particularly the role of MNK1 in replication and translation of viral genome.
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Affiliation(s)
- Ram Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India; Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Nitin Khandelwal
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Riyesh Thachamvally
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Bhupendra Nath Tripathi
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sanjay Barua
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sudhir Kumar Kashyap
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Sunil Maherchandani
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Naveen Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India.
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Abstract
Influenza is a negative-sense single-stranded RNA virus with segmented genome. Each segment is encapsidated by a ribonucleoprotein (RNP) complex composed of RNA-dependent RNA polymerase (RdRP) and multiple copies of nucleoprotein (NP). The RNP complex plays a crucial role in viral life cycle, supporting and regulating transcription and replication of viral genome in infected cells. The structural characterization of RdRP and RNP in recent years has shed light on its functions and mechanism of action. In this review, we summarize current understanding on the structure of RNP complex, as well as the structure of each subunit. Crucial functions of RNP are also discussed.
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Affiliation(s)
- Chun-Yeung Lo
- Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, China
| | - Yun-Sang Tang
- Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, China
| | - Pang-Chui Shaw
- Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong, China.
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Lin W, Qiu P, Jin J, Liu S, Ul Islam S, Yang J, Zhang J, Kormelink R, Du Z, Wu Z. The Cap Snatching of Segmented Negative Sense RNA Viruses as a Tool to Map the Transcription Start Sites of Heterologous Co-infecting Viruses. Front Microbiol 2017; 8:2519. [PMID: 29312219 PMCID: PMC5735111 DOI: 10.3389/fmicb.2017.02519] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/04/2017] [Indexed: 01/06/2023] Open
Abstract
Identification of the transcription start sites (TSSs) of a virus is of great importance to understand and dissect the mechanism of viral genome transcription but this often requires costly and laborious experiments. Many segmented negative-sense RNA viruses (sNSVs) cleave capped leader sequences from a large variety of mRNAs and use these cleaved leaders as primers for transcription in a conserved process called cap snatching. The recent developments in high-throughput sequencing have made it possible to determine most, if not all, of the capped RNAs snatched by a sNSV. Here, we show that rice stripe tenuivirus (RSV), a plant-infecting sNSV, co-infects Nicotiana benthamiana with two different begomoviruses and snatches capped leader sequences from their mRNAs. By determining the 5' termini of a single RSV mRNA with high-throughput sequencing, the 5' ends of almost all the mRNAs of the co-infecting begomoviruses could be identified and mapped on their genomes. The findings in this study provide support for the using of the cap snatching of sNSVs as a tool to map viral TSSs.
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Affiliation(s)
- Wenzhong Lin
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ping Qiu
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jing Jin
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shunmin Liu
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Saif Ul Islam
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinguang Yang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Jie Zhang
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Richard Kormelink
- Laboratory of Virology, Wageningen University and Research Centre, Wageningen, Netherlands
| | - Zhenguo Du
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, China
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, China
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47
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Rice Stripe Tenuivirus Has a Greater Tendency To Use the Prime-and-Realign Mechanism in Transcription of Genomic than in Transcription of Antigenomic Template RNAs. J Virol 2017; 92:JVI.01414-17. [PMID: 29046442 DOI: 10.1128/jvi.01414-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/04/2017] [Indexed: 01/06/2023] Open
Abstract
Most segmented negative-sense RNA viruses employ a process termed cap snatching, during which they snatch capped RNA leaders from host cellular mRNAs and use the snatched leaders as primers for transcription, leading to the synthesis of viral mRNAs with 5' heterogeneous sequences (HSs). With traditional methods, only a few HSs can be determined, and identification of their donors is difficult. Here, the mRNA 5' ends of Rice stripe tenuivirus (RSV) and Rice grassy stunt tenuivirus (RGSV) and those of their host rice were determined by high-throughput sequencing. Millions of tenuiviral HSs were obtained, and a large number of them mapped to the 5' ends of corresponding host cellular mRNAs. Repeats of the dinucleotide AC, which are complementary to the U1G2 of the tenuiviral template 3'-U1G2U3G4UUUCG, were found to be prevalent at the 3' termini of tenuiviral HSs. Most of these ACs did not match host cellular mRNAs, supporting the idea that tenuiviruses use the prime-and-realign mechanism during cap snatching. We previously reported a greater tendency of RSV than RGSV to use the prime-and-realign mechanism in transcription with leaders cap snatched from a coinfecting reovirus. Besides confirming this observation in natural tenuiviral infections, the data here additionally reveal that RSV has a greater tendency to use this mechanism in transcribing genomic than in transcribing antigenomic templates. The data also suggest that tenuiviruses cap snatch host cellular mRNAs from translation- and photosynthesis-related genes, and capped RNA leaders snatched by tenuiviruses base pair with U1/U3 or G2/G4 of viral templates. These results provide unprecedented insights into the cap-snatching process of tenuiviruses.IMPORTANCE Many segmented negative-sense RNA viruses (segmented NSVs) are medically or agriculturally important pathogens. The cap-snatching process is a promising target for the development of antiviral strategies against this group of viruses. However, many details of this process remain poorly characterized. Tenuiviruses constitute a genus of agriculturally important segmented NSVs, several members of which are major viral pathogens of rice. Here, we for the first time adopted a high-throughput sequencing strategy to determine the 5' heterogeneous sequences (HSs) of tenuiviruses and mapped them to host cellular mRNAs. Besides providing deep insights into the cap snatching of tenuiviruses, the data obtained provide clear evidence to support several previously proposed models regarding cap snatching. Curiously and importantly, the data here reveal that not only different tenuiviruses but also the same tenuivirus synthesizing different mRNAs use the prime-and-realign mechanism with different tendencies during their cap snatching.
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Harwig A, Landick R, Berkhout B. The Battle of RNA Synthesis: Virus versus Host. Viruses 2017; 9:v9100309. [PMID: 29065472 PMCID: PMC5691660 DOI: 10.3390/v9100309] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 12/13/2022] Open
Abstract
Transcription control is the foundation of gene regulation. Whereas a cell is fully equipped for this task, viruses often depend on the host to supply tools for their transcription program. Over the course of evolution and adaptation, viruses have found diverse ways to optimally exploit cellular host processes such as transcription to their own benefit. Just as cells are increasingly understood to employ nascent RNAs in transcription regulation, recent discoveries are revealing how viruses use nascent RNAs to benefit their own gene expression. In this review, we first outline the two different transcription programs used by viruses, i.e., transcription (DNA-dependent) and RNA-dependent RNA synthesis. Subsequently, we use the distinct stages (initiation, elongation, termination) to describe the latest insights into nascent RNA-mediated regulation in the context of each relevant stage.
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Affiliation(s)
- Alex Harwig
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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Sikora D, Rocheleau L, Brown EG, Pelchat M. Influenza A virus cap-snatches host RNAs based on their abundance early after infection. Virology 2017. [PMID: 28646652 DOI: 10.1016/j.virol.2017.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The influenza A virus RNA polymerase cleaves the 5' ends of host RNAs and uses these RNA fragments as primers for viral mRNA synthesis. We performed deep sequencing of the 5' host-derived ends of the eight viral mRNAs of influenza A/Puerto Rico/8/1934 (H1N1) virus in infected A549 cells, and compared the population to those of A/Hong Kong/1/1968 (H3N2) and A/WSN/1933 (H1N1). In the three strains, the viral RNAs target different populations of host RNAs. Host RNAs are cap-snatched based on their abundance, and we found that RNAs encoding proteins involved in metabolism are overrepresented in the cap-snatched populations. Because this overrepresentation could be a reflection of the host response early after infection, and thus of the increased availability of these transcripts, our results suggest that host RNAs are cap-snatched mainly based on their abundance without preferential targeting.
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Affiliation(s)
- Dorota Sikora
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Lynda Rocheleau
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Earl G Brown
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5.
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50
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Pflug A, Lukarska M, Resa-Infante P, Reich S, Cusack S. Structural insights into RNA synthesis by the influenza virus transcription-replication machine. Virus Res 2017; 234:103-117. [PMID: 28115197 DOI: 10.1016/j.virusres.2017.01.013] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/31/2016] [Accepted: 01/13/2017] [Indexed: 12/22/2022]
Abstract
Influenza virus is a segmented, negative strand RNA virus with each genome segment being packaged in a distinct ribonucleoprotein particle (RNP). The RNP consists of the heterotrimeric viral RNA-dependent RNA polymerase bound to the conserved 5' and 3' ends of the genome segment (the viral promoter) with the rest of the viral RNA (vRNA) being covered by multiple copies of nucleoprotein. This review focusses on the new insights that recent crystal structures have given into the detailed molecular mechanisms by which the polymerase performs both transcription and replication of the vRNA genome. Promoter binding, in particular that of 5' end, is essential to allosterically activate all polymerase functions. Transcription is initiated by the hijacking of nascent, capped host transcripts by the process of 'cap-snatching', for which the viral polymerase makes an essential interaction with the C-terminal domain (CTD) of cellular RNA polymerase II. The structures allow a coherent mechanistic model of the subsequent cap-snatching, cap-dependent priming, elongation and self-polyadenylation steps of viral mRNA synthesis. During replication, the vRNA is copied without modification into complementary RNA (cRNA) which is packaged into cRNPs. A priming loop located in the polymerase active site is required for the unprimed synthesis of cRNA from vRNA, but is not required for cRNA to vRNA replication due to differences in the mode of initiation of RNA synthesis. Overall a picture emerges of influenza polymerase being a highly complex, flexible and dynamic machine. The challenge remains to understand in more detail how it functions within the RNP and how interacting host factors modulate its activity in the cellular context. Finally, these detailed insights have opened up new opportunities for structure-based antiviral drug design targeting multiple aspects of polymerase function.
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Affiliation(s)
- Alexander Pflug
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Maria Lukarska
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Patricia Resa-Infante
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Stefan Reich
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France.
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