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Arragain B, Krischuns T, Pelosse M, Drncova P, Blackledge M, Naffakh N, Cusack S. Structures of influenza A and B replication complexes give insight into avian to human host adaptation and reveal a role of ANP32 as an electrostatic chaperone for the apo-polymerase. Nat Commun 2024; 15:6910. [PMID: 39160148 PMCID: PMC11333492 DOI: 10.1038/s41467-024-51007-3] [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: 02/08/2024] [Accepted: 07/16/2024] [Indexed: 08/21/2024] Open
Abstract
Replication of influenza viral RNA depends on at least two viral polymerases, a parental replicase and an encapsidase, and cellular factor ANP32. ANP32 comprises an LRR domain and a long C-terminal low complexity acidic region (LCAR). Here we present evidence suggesting that ANP32 is recruited to the replication complex as an electrostatic chaperone that stabilises the encapsidase moiety within apo-polymerase symmetric dimers that are distinct for influenza A and B polymerases. The ANP32 bound encapsidase, then forms the asymmetric replication complex with the replicase, which is embedded in a parental ribonucleoprotein particle (RNP). Cryo-EM structures reveal the architecture of the influenza A and B replication complexes and the likely trajectory of the nascent RNA product into the encapsidase. The cryo-EM map of the FluB replication complex shows extra density attributable to the ANP32 LCAR wrapping around and stabilising the apo-encapsidase conformation. These structures give new insight into the various mutations that adapt avian strain polymerases to use the distinct ANP32 in mammalian cells.
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Affiliation(s)
- Benoît Arragain
- European Molecular Biology Laboratory, Grenoble, Cedex 9, France
| | - Tim Krischuns
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, RNA Biology of Influenza Virus, Paris, France
- Heidelberg University, Department of Infectious Diseases, Virology, Schaller Research Group, Heidelberg, Germany
| | - Martin Pelosse
- European Molecular Biology Laboratory, Grenoble, Cedex 9, France
| | - Petra Drncova
- European Molecular Biology Laboratory, Grenoble, Cedex 9, France
| | - Martin Blackledge
- Institut de Biologie Structurale, Université Grenoble-Alpes-CEA-CNRS UMR5075, Grenoble, France
| | - Nadia Naffakh
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, RNA Biology of Influenza Virus, Paris, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble, Cedex 9, France.
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2
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Giacchello I, Cianciusi A, Bertagnin C, Bonomini A, Francesconi V, Mori M, Carbone A, Musumeci F, Loregian A, Schenone S. Exploring a New Generation of Pyrimidine and Pyridine Derivatives as Anti-Influenza Agents Targeting the Polymerase PA-PB1 Subunits Interaction. Pharmaceutics 2024; 16:954. [PMID: 39065650 PMCID: PMC11279468 DOI: 10.3390/pharmaceutics16070954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/08/2024] [Accepted: 07/12/2024] [Indexed: 07/28/2024] Open
Abstract
The limited range of available flu treatments due to virus mutations and drug resistance have prompted the search for new therapies. RNA-dependent RNA polymerase (RdRp) is a heterotrimeric complex of three subunits, i.e., polymerase acidic protein (PA) and polymerase basic proteins 1 and 2 (PB1 and PB2). It is widely recognized as one of the most promising anti-flu targets because of its critical role in influenza infection and high amino acid conservation. In particular, the disruption of RdRp complex assembly through protein-protein interaction (PPI) inhibition has emerged as a valuable strategy for discovering a new therapy. Our group previously identified the 3-cyano-4,6-diphenyl-pyridine core as a privileged scaffold for developing PA-PB1 PPI inhibitors. Encouraged by these findings, we synthesized a small library of pyridine and pyrimidine derivatives decorated with a thio-N-(m-tolyl)acetamide side chain (compounds 2a-n) or several amino acid groups (compounds 3a-n) at the C2 position. Interestingly, derivative 2d, characterized by a pyrimidine core and a phenyl and 4-chloro phenyl ring at the C4 and C6 positions, respectively, showed an IC50 value of 90.1 μM in PA-PB1 ELISA, an EC50 value of 2.8 μM in PRA, and a favorable cytotoxic profile, emerging as a significant breakthrough in the pursuit of new PPI inhibitors. A molecular modeling study was also completed as part of this project, allowing us to clarify the biological profile of these compounds.
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Affiliation(s)
- Ilaria Giacchello
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
| | - Annarita Cianciusi
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
| | - Chiara Bertagnin
- Department of Molecular Medicine, University of Padua, Via A. Gabelli 63, 35121 Padua, Italy; (C.B.); (A.B.); (A.L.)
| | - Anna Bonomini
- Department of Molecular Medicine, University of Padua, Via A. Gabelli 63, 35121 Padua, Italy; (C.B.); (A.B.); (A.L.)
| | - Valeria Francesconi
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy;
| | - Anna Carbone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
| | - Francesca Musumeci
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
| | - Arianna Loregian
- Department of Molecular Medicine, University of Padua, Via A. Gabelli 63, 35121 Padua, Italy; (C.B.); (A.B.); (A.L.)
| | - Silvia Schenone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy; (I.G.); (A.C.); (V.F.); (S.S.)
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3
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Sun J, Kuai L, Zhang L, Xie Y, Zhang Y, Li Y, Peng Q, Shao Y, Yang Q, Tian WX, Zhu J, Qi J, Shi Y, Deng T, Gao GF. NS2 induces an influenza A RNA polymerase hexamer and acts as a transcription to replication switch. EMBO Rep 2024:10.1038/s44319-024-00208-4. [PMID: 39026012 DOI: 10.1038/s44319-024-00208-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/20/2024] Open
Abstract
Genome transcription and replication of influenza A virus (FluA), catalyzed by viral RNA polymerase (FluAPol), are delicately controlled across the virus life cycle. A switch from transcription to replication occurring at later stage of an infection is critical for progeny virion production and viral non-structural protein NS2 has been implicated in regulating the switch. However, the underlying regulatory mechanisms and the structure of NS2 remained elusive for years. Here, we determine the cryo-EM structure of the FluAPol-NS2 complex at ~3.0 Å resolution. Surprisingly, three domain-swapped NS2 dimers arrange three symmetrical FluPol dimers into a highly ordered barrel-like hexamer. Further structural and functional analyses demonstrate that NS2 binding not only hampers the interaction between FluAPol and the Pol II CTD because of steric conflicts, but also impairs FluAPol transcriptase activity by stalling it in the replicase conformation. Moreover, this is the first visualization of the full-length NS2 structure. Our findings uncover key molecular mechanisms of the FluA transcription-replication switch and have implications for the development of antivirals.
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Affiliation(s)
- Junqing Sun
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, China
- Shanxi Academy of Advanced Research and Innovation, Taiyuan, 030032, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lu Kuai
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lei Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- Institute of Pediatrics, Shenzhen Children's Hospital, Shenzhen, 518026, China
| | - Yufeng Xie
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Yanfang Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yan Li
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qi Peng
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yuekun Shao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qiuxian Yang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wen-Xia Tian
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, 030801, China
| | - Junhao Zhu
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yi Shi
- Shanxi Academy of Advanced Research and Innovation, Taiyuan, 030032, China.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Tao Deng
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - George F Gao
- Shanxi Academy of Advanced Research and Innovation, Taiyuan, 030032, China.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049, China.
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4
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Staller E, Carrique L, Swann OC, Fan H, Keown JR, Sheppard CM, Barclay WS, Grimes JM, Fodor E. Structures of H5N1 influenza polymerase with ANP32B reveal mechanisms of genome replication and host adaptation. Nat Commun 2024; 15:4123. [PMID: 38750014 PMCID: PMC11096171 DOI: 10.1038/s41467-024-48470-3] [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: 01/05/2024] [Accepted: 05/01/2024] [Indexed: 05/18/2024] Open
Abstract
Avian influenza A viruses (IAVs) pose a public health threat, as they are capable of triggering pandemics by crossing species barriers. Replication of avian IAVs in mammalian cells is hindered by species-specific variation in acidic nuclear phosphoprotein 32 (ANP32) proteins, which are essential for viral RNA genome replication. Adaptive mutations enable the IAV RNA polymerase (FluPolA) to surmount this barrier. Here, we present cryo-electron microscopy structures of monomeric and dimeric avian H5N1 FluPolA with human ANP32B. ANP32B interacts with the PA subunit of FluPolA in the monomeric form, at the site used for its docking onto the C-terminal domain of host RNA polymerase II during viral transcription. ANP32B acts as a chaperone, guiding FluPolA towards a ribonucleoprotein-associated FluPolA to form an asymmetric dimer-the replication platform for the viral genome. These findings offer insights into the molecular mechanisms governing IAV genome replication, while enhancing our understanding of the molecular processes underpinning mammalian adaptations in avian-origin FluPolA.
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Affiliation(s)
- Ecco Staller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Loïc Carrique
- Division of Structural Biology, Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Olivia C Swann
- Section of Molecular Virology, Imperial College London, London, UK
| | - Haitian Fan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- School of Basic Medical Sciences, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Jeremy R Keown
- Division of Structural Biology, Centre for Human Genetics, University of Oxford, Oxford, UK
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Carol M Sheppard
- Section of Molecular Virology, Imperial College London, London, UK
| | - Wendy S Barclay
- Section of Molecular Virology, Imperial College London, London, UK
| | - Jonathan M Grimes
- Division of Structural Biology, Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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5
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Lieber CM, Kang HJ, Aggarwal M, Lieberman NA, Sobolik EB, Yoon JJ, Natchus MG, Cox RM, Greninger AL, Plemper RK. Influenza A virus resistance to 4'-fluorouridine coincides with viral attenuation in vitro and in vivo. PLoS Pathog 2024; 20:e1011993. [PMID: 38300953 PMCID: PMC10863857 DOI: 10.1371/journal.ppat.1011993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/13/2024] [Accepted: 01/22/2024] [Indexed: 02/03/2024] Open
Abstract
Pre-existing or rapidly emerging resistance of influenza viruses to approved antivirals makes the development of novel therapeutics to mitigate seasonal influenza and improve preparedness against future influenza pandemics an urgent priority. We have recently identified the chain-terminating broad-spectrum nucleoside analog clinical candidate 4'-fluorouridine (4'-FlU) and demonstrated oral efficacy against seasonal, pandemic, and highly pathogenic avian influenza viruses in the mouse and ferret model. Here, we have resistance-profiled 4'-FlU against a pandemic A/CA/07/2009 (H1N1) (CA09). In vitro viral adaptation yielded six independently generated escape lineages with distinct mutations that mediated moderate resistance to 4'-FlU in the genetically controlled background of recombinant CA09 (recCA09). Mutations adhered to three distinct structural clusters that are all predicted to affect the geometry of the active site of the viral RNA-dependent RNA polymerase (RdRP) complex for phosphodiester bond formation. Escape could be achieved through an individual causal mutation, a combination of mutations acting additively, or mutations functioning synergistically. Fitness of all resistant variants was impaired in cell culture, and all were attenuated in the mouse model. Oral 4'-FlU administered at lowest-efficacious (2 mg/kg) or elevated (10 mg/kg) dose overcame moderate resistance when mice were inoculated with 10 LD50 units of parental or resistant recCA09, demonstrated by significantly reduced virus load and complete survival. In the ferret model, invasion of the lower respiratory tract by variants representing four adaptation lineages was impaired. Resistant variants were either transmission-incompetent, or spread to untreated sentinels was fully blocked by therapeutic treatment of source animals with 4'-FlU.
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Affiliation(s)
- Carolin M. Lieber
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
| | - Hae-Ji Kang
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
| | - Megha Aggarwal
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
| | - Nicole A. Lieberman
- Virology Division, Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, Washington, United States of America
| | - Elizabeth B. Sobolik
- Virology Division, Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, Washington, United States of America
| | - Jeong-Joong Yoon
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
| | - Michael G. Natchus
- Emory Institute for Drug Development, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Robert M. Cox
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
| | - Alexander L. Greninger
- Virology Division, Department of Laboratory Medicine and Pathology, University of Washington Medical Center, Seattle, Washington, United States of America
| | - Richard K. Plemper
- Center for Translational Antiviral Research, Georgia State University Institute for Biomedical Sciences, Atlanta, Georgia, United States of America
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6
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Cao M, Jia Q, Li J, Zhao L, Zhu L, Zhang Y, Li S, Deng T. Naturally occurring PA E206K point mutation in 2009 H1N1 pandemic influenza viruses impairs viral replication at high temperatures. Virol Sin 2024; 39:71-80. [PMID: 37979619 PMCID: PMC10877435 DOI: 10.1016/j.virs.2023.11.005] [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: 07/18/2023] [Accepted: 11/10/2023] [Indexed: 11/20/2023] Open
Abstract
The emergence of influenza virus A pandemic H1N1 in April 2009 marked the first pandemic of the 21st century. In this study, we observed significant differences in the polymerase activities of two clinical 2009 H1N1 influenza A virus isolates from Chinese and Japanese patients. Sequence comparison of the three main protein subunits (PB2, PB1, and PA) of the viral RNA-dependent RNA polymerase complex and subsequent mutational analysis revealed that a single amino acid substitution (E206K) was responsible for the observed impaired replication phenotype. Further in vitro experiments showed that presence of PAE206K decreased the replication of influenza A/WSN/33 virus in mammalian cells and a reduction in the virus's pathogenicity in vivo. Mechanistic studies revealed that PAE206K is a temperature-sensitive mutant associated with the inability to transport PB1-PA complex to the nucleus at high temperature (39.5 °C). Hence, this naturally occurring variant in the PA protein represents an ideal candidate mutation for the development of live attenuated influenza vaccines.
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Affiliation(s)
- Mengmeng Cao
- National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Qiannan Jia
- National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Jinghua Li
- National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Lili Zhao
- National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Li Zhu
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yufan Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shan Li
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Tao Deng
- National Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China; CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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7
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Zhang L, Shao Y, Wang Y, Yang Q, Guo J, Gao GF, Deng T. Twenty natural amino acid substitution screening at the last residue 121 of influenza A virus NS2 protein reveals the critical role of NS2 in promoting virus genome replication by coordinating with viral polymerase. J Virol 2024; 98:e0116623. [PMID: 38054704 PMCID: PMC10804943 DOI: 10.1128/jvi.01166-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/20/2023] [Indexed: 12/07/2023] Open
Abstract
Both influenza A virus genome transcription (vRNA→mRNA) and replication (vRNA→cRNA→vRNA), catalyzed by the influenza RNA polymerase (FluPol), are dynamically regulated across the virus life cycle. It has been reported that the last amino acid I121 of the viral NS2 protein plays a critical role in promoting viral genome replication in influenza mini-replicon systems. Here, we performed a 20 natural amino acid substitution screening at residue NS2-I121 in the context of virus infection. We found that the hydrophobicity of the residue 121 is essential for virus survival. Interestingly, through serial passage of the rescued mutant viruses, we further identified adaptive mutations PA-K19E and PB1-S713N on FluPol which could effectively compensate for the replication-promoting defect caused by NS2-I121 mutation in the both mini-replicon and virus infection systems. Structural analysis of different functional states of FluPol indicates that PA-K19E and PB1-S713N could stabilize the replicase conformation of FluPol. By using a cell-based NanoBiT complementary reporter assay, we further demonstrate that both wild-type NS2 and PA-K19E/PB1-S713N could enhance FluPol dimerization, which is necessary for genome replication. These results reveal the critical role NS2 plays in promoting viral genome replication by coordinating with FluPol.IMPORTANCEThe intrinsic mechanisms of influenza RNA polymerase (FluPol) in catalyzing viral genome transcription and replication have been largely resolved. However, the mechanisms of how transcription and replication are dynamically regulated remain elusive. We recently reported that the last amino acid of the viral NS2 protein plays a critical role in promoting viral genome replication in an influenza mini-replicon system. Here, we conducted a 20 amino acid substitution screening at the last residue 121 in virus rescue and serial passage. Our results demonstrate that the replication-promoting function of NS2 is important for virus survival and efficient multiplication. We further show evidence that NS2 and NS2-I121 adaptive mutations PA-K19E/PB1-S713N regulate virus genome replication by promoting FluPol dimerization. This work highlights the coordination between NS2 and FluPol in fulfilling efficient genome replication. It further advances our understanding of the regulation of viral RNA synthesis for influenza A virus.
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Affiliation(s)
- Lei Zhang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- />Institute of Pediatrics, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yuekun Shao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yingying Wang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiuxian Yang
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jiamei Guo
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - George F. Gao
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tao Deng
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Arragain B, Pelosse M, Thompson A, Cusack S. Structural and functional analysis of the minimal orthomyxovirus-like polymerase of Tilapia Lake Virus from the highly diverged Amnoonviridae family. Nat Commun 2023; 14:8145. [PMID: 38066000 PMCID: PMC10709604 DOI: 10.1038/s41467-023-44044-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Tilapia Lake Virus (TiLV), a recently discovered pathogen of tilapia fish, belongs to the Amnoonviridae family from the Articulavirales order. Its ten genome segments have characteristic conserved ends and encode proteins with no known homologues, apart from the segment 1, which encodes an orthomyxo-like RNA-dependent-RNA polymerase core subunit. Here we show that segments 1-3 encode respectively the PB1, PB2 and PA-like subunits of an active heterotrimeric polymerase that maintains all domains found in the distantly related influenza polymerase, despite an unprecedented overall size reduction of 40%. Multiple high-resolution cryo-EM structures of TiLV polymerase in pre-initiation, initiation and active elongation states, show how it binds the vRNA and cRNA promoters and performs RNA synthesis, with both transcriptase and replicase configurations being characterised. However, the highly truncated endonuclease-like domain appears inactive and the putative cap-binding domain is autoinhibited, emphasising that many functional aspects of TiLV polymerase remain to be elucidated.
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Affiliation(s)
- Benoit Arragain
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, Cedex 9, France
| | - Martin Pelosse
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, Cedex 9, France
| | - Albert Thompson
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, Cedex 9, France
- The Francis Crick Institute, London, UK
| | - Stephen Cusack
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, Cedex 9, France.
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9
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Lieber CM, Kang HJ, Aggarwal M, Lieberman NA, Sobolik EB, Yoon JJ, Natchus MG, Cox RM, Greninger AL, Plemper RK. Influenza A virus resistance to 4'-fluorouridine coincides with viral attenuation in vitro and in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.20.563370. [PMID: 37905070 PMCID: PMC10614940 DOI: 10.1101/2023.10.20.563370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Pre-existing or rapidly emerging resistance of influenza viruses to approved antivirals makes the development of novel therapeutics to mitigate seasonal influenza and improve preparedness against future influenza pandemics an urgent priority. We have recently identified the chain-terminating broad-spectrum nucleoside analog clinical candidate 4'-fluorouridine (4'-FlU) and demonstrated oral efficacy against seasonal, pandemic, and highly pathogenic avian influenza viruses in the mouse and ferret model. Here, we have resistance-profiled 4'-FlU against a pandemic A/CA/07/2009 (H1N1) (CA09). In vitro viral adaptation yielded six independently generated escape lineages with distinct mutations that mediated moderate resistance to 4'-FlU in the genetically controlled background of recombinant CA09 (recCA09). Mutations adhered to three distinct structural clusters that are all predicted to affect the geometry of the active site of the viral RNA-dependent RNA polymerase (RdRP) complex for phosphodiester bond formation. Escape could be achieved through an individual causal mutation, a combination of mutations acting additively, or mutations functioning synergistically. Fitness of all resistant variants was impaired in cell culture, and all were attenuated in the mouse model. Oral 4'-FlU administered at lowest-efficacious (2 mg/kg) or elevated (10 mg/kg) dose overcame moderate resistance when mice were inoculated with 10 LD 50 units of parental or resistant recCA09, demonstrated by significantly reduced virus load and complete survival. In the ferret model, invasion of the lower respiratory tract by variants representing four adaptation lineages was impaired. Resistant variants were either transmission-incompetent, or spread to untreated sentinels was fully blocked by therapeutic treatment of source animals with 4'-FlU. Author Summary Reduced sensitivity to FDA-approved influenza drugs is a major obstacle to effective antiviral therapy. We have previously demonstrated oral efficacy of a novel clinical candidate drug, 4'-FlU, against seasonal, pandemic, and highly pathogenic avian influenza viruses. In this study, we have determined possible routes of influenza virus escape from 4'-FlU and addressed whether resistance imposes a viral fitness penalty, affecting pathogenicity or ability to transmit. We identified three distinct clusters of mutations that lead to moderately reduced viral sensitivity to the drug. Testing of resistant variants against two chemically unrelated nucleoside analog inhibitors of influenza virus, conditionally approved favipiravir and the broad-spectrum SARS-CoV-2 drug molnupiravir, revealed cross-resistance of one cluster with favipiravir, whereas no viral escape from molnupiravir was noted. We found that the resistant variants are severely attenuated in mice, impaired in their ability to invade the lower respiratory tract and cause viral pneumonia in ferrets, and transmission-defective or compromised. We could fully mitigate lethal infection of mice with the resistant variants with standard or 5-fold elevated oral dose of 4'-FlU. These results demonstrate that partial viral escape from 4'-FlU is feasible in principle, but escape mutation clusters are unlikely to reach clinical significance or persist in circulating influenza virus strains.
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10
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Gilbertson B, Duncan M, Subbarao K. Role of the viral polymerase during adaptation of influenza A viruses to new hosts. Curr Opin Virol 2023; 62:101363. [PMID: 37672875 DOI: 10.1016/j.coviro.2023.101363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 09/08/2023]
Abstract
As a group, influenza-A viruses (IAV) infect a wide range of animal hosts, however, they are constrained to infecting selected host species by species-specific interactions between the host and virus, that are required for efficient replication of the viral RNA genome. When IAV cross the species barrier, they acquire mutations in the viral genome to enable interactions with the new host factors, or to compensate for their loss. The viral polymerase genes polymerase basic 1, polymerase basic 2, and polymerase-acidic are important sites of host adaptation. In this review, we discuss why the viral polymerase is so vital to the process of host adaptation, look at some of the known viral mutations, and host factors involved in adaptation, particularly of avian IAV to mammalian hosts.
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Affiliation(s)
- Brad Gilbertson
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Melanie Duncan
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Kanta Subbarao
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
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11
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Peng Q, Yuan B, Cheng J, Wang M, Gao S, Bai S, Zhao X, Qi J, Gao GF, Shi Y. Molecular mechanism of de novo replication by the Ebola virus polymerase. Nature 2023; 622:603-610. [PMID: 37699521 DOI: 10.1038/s41586-023-06608-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023]
Abstract
Non-segmented negative-strand RNA viruses, including Ebola virus (EBOV), rabies virus, human respiratory syncytial virus and pneumoviruses, can cause respiratory infections, haemorrhagic fever and encephalitis in humans and animals, and are considered a substantial health and economic burden worldwide1. Replication and transcription of the viral genome are executed by the large (L) polymerase, which is a promising target for the development of antiviral drugs. Here, using the L polymerase of EBOV as a representative, we show that de novo replication of L polymerase is controlled by the specific 3' leader sequence of the EBOV genome in an enzymatic assay, and that formation of at least three base pairs can effectively drive the elongation process of RNA synthesis independent of the specific RNA sequence. We present the high-resolution structures of the EBOV L-VP35-RNA complex and show that the 3' leader RNA binds in the template entry channel with a distinctive stable bend conformation. Using mutagenesis assays, we confirm that the bend conformation of the RNA is required for the de novo replication activity and reveal the key residues of the L protein that stabilize the RNA conformation. These findings provide a new mechanistic understanding of RNA synthesis for polymerases of non-segmented negative-strand RNA viruses, and reveal important targets for the development of antiviral drugs.
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Affiliation(s)
- Qi Peng
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Bin Yuan
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jinlong Cheng
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Min Wang
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Siwei Gao
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Suran Bai
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xuejin Zhao
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jianxun Qi
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- Beijing Life Science Academy, Beijing, China.
| | - George F Gao
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- Beijing Life Science Academy, Beijing, China.
- Center for Influenza Research and Early-warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Disease (CEEID), Chinese Academy of Sciences, Beijing, China.
- Research Unit of Adaptive Evolution and Control of Emerging Viruses, Chinese Academy of Medical Sciences, Beijing, China.
| | - Yi Shi
- International Institute of Vaccine Research and Innovation (iVac), Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- Beijing Life Science Academy, Beijing, China.
- Center for Influenza Research and Early-warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Disease (CEEID), Chinese Academy of Sciences, Beijing, China.
- Research Unit of Adaptive Evolution and Control of Emerging Viruses, Chinese Academy of Medical Sciences, Beijing, China.
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12
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Camacho-Zarco AR, Yu L, Krischuns T, Dedeoglu S, Maurin D, Bouvignies G, Crépin T, Ruigrok RWH, Cusack S, Naffakh N, Blackledge M. Multivalent Dynamic Colocalization of Avian Influenza Polymerase and Nucleoprotein by Intrinsically Disordered ANP32A Reveals the Molecular Basis of Human Adaptation. J Am Chem Soc 2023; 145:20985-21001. [PMID: 37707433 PMCID: PMC10540212 DOI: 10.1021/jacs.3c06965] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Indexed: 09/15/2023]
Abstract
Adaptation of avian influenza RNA polymerase (FluPol) to human cells requires mutations on the 627-NLS domains of the PB2 subunit. The E627K adaptive mutation compensates a 33-amino-acid deletion in the acidic intrinsically disordered domain of the host transcription regulator ANP32A, a deletion that restricts FluPol activity in mammalian cells. The function of ANP32A in the replication transcription complex and in particular its role in host restriction remains poorly understood. Here we characterize ternary complexes formed between ANP32A, FluPol, and the viral nucleoprotein, NP, supporting the putative role of ANP32A in shuttling NP to the replicase complex. We demonstrate that while FluPol and NP can simultaneously bind distinct linear motifs on avian ANP32A, the deletion in the shorter human ANP32A blocks this mode of colocalization. NMR reveals that NP and human-adapted FluPol, containing the E627 K mutation, simultaneously bind the identical extended linear motif on human ANP32A in an electrostatically driven, highly dynamic and multivalent ternary complex. This study reveals a probable molecular mechanism underlying host adaptation, whereby E627K, which enhances the basic surface of the 627 domain, is selected to confer the necessary multivalent properties to allow ANP32A to colocalize NP and FluPol in human cells.
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Affiliation(s)
- Aldo R. Camacho-Zarco
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Lefan Yu
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Tim Krischuns
- Institut
Pasteur, Université Paris Cité,
CNRS UMR3569, Unité Biologie des ARN et Virus Influenza, 75015 Paris, France
| | - Selin Dedeoglu
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Damien Maurin
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Guillaume Bouvignies
- Laboratoire
des Biomolécules, Département de Chimie, École
Normale Supérieur, UPMC Université Paris 06, CNRS, PSL Research University, 24 rue Lhomond, 75005 Paris, France
| | - Thibaut Crépin
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Rob W. H. Ruigrok
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Stephan Cusack
- European
Molecular Biology Laboratory, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Nadia Naffakh
- Institut
Pasteur, Université Paris Cité,
CNRS UMR3569, Unité Biologie des ARN et Virus Influenza, 75015 Paris, France
| | - Martin Blackledge
- Institut
de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS
UMR5075, 71 Avenue des
Martyrs, 38000 Grenoble, France
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13
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Li H, Wu Y, Li M, Guo L, Gao Y, Wang Q, Zhang J, Lai Z, Zhang X, Zhu L, Lan P, Rao Z, Liu Y, Liang H. An intermediate state allows influenza polymerase to switch smoothly between transcription and replication cycles. Nat Struct Mol Biol 2023; 30:1183-1192. [PMID: 37488357 DOI: 10.1038/s41594-023-01043-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Influenza polymerase (FluPol) transcribes viral mRNA at the beginning of the viral life cycle and initiates genome replication after viral protein synthesis. However, it remains poorly understood how FluPol switches between its transcription and replication states, especially given that the structural bases of these two functions are fundamentally different. Here we propose a mechanism by which FluPol achieves functional switching between these two states through a previously unstudied conformation, termed an 'intermediate state'. Using cryo-electron microscopy, we obtained a structure of the intermediate state of H5N1 FluPol at 3.7 Å, which is characterized by a blocked cap-binding domain and a contracted core region. Structural analysis results suggest that the intermediate state may allow FluPol to transition smoothly into either the transcription or replication state. Furthermore, we show that the formation of the intermediate state is required for both the transcription and replication activities of FluPol, leading us to conclude that the transcription and replication cycles of FluPol are regulated via this intermediate state.
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Affiliation(s)
- Huanhuan Li
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yixi Wu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Minke Li
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Lu Guo
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yaqi Gao
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Quan Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jihua Zhang
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Zhaohua Lai
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China
| | - Xing Zhang
- Departments of Biophysics and Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, China
| | - Lixin Zhu
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ping Lan
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zihe Rao
- Laboratory of Structural Biology, Tsinghua University, Beijing, China
| | - Yingfang Liu
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China.
- Department of General Surgery, Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
| | - Huanhuan Liang
- Shenzhen Key Laboratory for Systems Medicine in Inflammatory Diseases, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, China.
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14
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A structural understanding of influenza virus genome replication. Trends Microbiol 2023; 31:308-319. [PMID: 36336541 DOI: 10.1016/j.tim.2022.09.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/27/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
Influenza virus contains a single-stranded negative-sense RNA genome. Replication of the genome is carried out by the viral RNA-dependent RNA polymerase in the context of the viral ribonucleoprotein (RNP) complex, through a positive-sense complementary RNA intermediate. Genome replication is tightly controlled through interactions with accessory viral and host factors. Propelled by developments in recombinant protein expression, and technical improvements in X-ray crystallography and cryo-electron microscopy, snapshots of the replication process have been captured. Here, we review how recent structural data shed light on the molecular mechanisms of influenza virus genome replication, in particular, encapsidation of nascent RNA, de novo RNP assembly, and regulation of replication initiation through interactions with host and viral cues.
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15
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Avian Influenza A Virus Polymerase Can Utilize Human ANP32 Proteins To Support cRNA but Not vRNA Synthesis. mBio 2023; 14:e0339922. [PMID: 36645303 PMCID: PMC9973007 DOI: 10.1128/mbio.03399-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Host restriction limits the emergence of novel pandemic strains from the influenza A virus avian reservoir. For efficient replication in mammalian cells, the avian influenza RNA-dependent RNA polymerase must adapt to use human orthologues of the host factor ANP32, which lack a 33-amino-acid insertion relative to avian ANP32A. Here, we find that influenza polymerase requires ANP32 proteins to support both steps of genome replication: cRNA and vRNA synthesis. However, avian strains are only restricted in vRNA synthesis in human cells. Therefore, avian influenza polymerase can use human ANP32 orthologues to support cRNA synthesis, without acquiring mammalian adaptations. This implies a fundamental difference in the mechanism by which ANP32 proteins support cRNA versus vRNA synthesis. IMPORTANCE To infect humans and cause a pandemic, avian influenza must first adapt to use human versions of the proteins the virus hijacks for replication, instead of the avian orthologues found in bird cells. One critical host protein is ANP32. Understanding the details of how host proteins such as ANP32 support viral activity may allow the design of new antiviral strategies that disrupt these interactions. Here, we use cells that lack ANP32 to unambiguously demonstrate ANP32 is needed for both steps of influenza genome replication. Unexpectedly, however, we found that avian influenza can use human ANP32 proteins for the first step of replication, to copy a complementary strand, without adaptation but can only utilize avian ANP32 for the second step of replication that generates new genomes. This suggests ANP32 may have a distinct role in supporting the second step of replication, and it is this activity that is specifically blocked when avian influenza infects human cells.
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16
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Kumar G, Singh AK, Agarwal D. Structural and functional characterization of RNA dependent RNA polymerase of Macrobrachium rosenbergii nodavirus (MnRdRp). J Biomol Struct Dyn 2023; 41:12825-12837. [PMID: 36757137 DOI: 10.1080/07391102.2023.2175384] [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: 07/21/2022] [Accepted: 01/07/2023] [Indexed: 02/10/2023]
Abstract
Macrobrachium rosenbergii is a highly valued farmed freshwater species and its production has been affected globally by white tail disease caused by M. rosenbergii nodavirus (MrNV). MrNV is a single stranded positive sense RNA virus encoding RNA-dependent RNA polymerase (RdRp) for genome replication. Due to its essentiality for pathogenesis, it is an important drug target. The domain prediction of the complete sequence revealed the presence of two enzymatic regions namely methyl transferase and RdRp separated by transmembrane region. The predicted three-dimensional (3D) structure of MnRdRp using AlphaFold 2 shows that the structure is composed of three major sub-domains common for other polymerases namely fingers, palm and thumb. Structural similarity search revealed its similarity with other flaviviridea members especially with BVDV RdRp (BvdvRdRp). The structure of fingers and palm sub-domains is more conserved than the thumb sub-domain. A small α-helix named 'priming helix' having conserve Tyr was identified at position 829-833 with a potential role in de novo initiation. Analysis of electrostatic potential revealed that nucleotide and template channels are electropositive. Metal binding residues were identified as Asp599, Asp704 and Asp705. The α and β phosphates of incoming nucleotide interact with two Mn2+, Arg455 and Arg537. For recognition of 2'-OH of incoming rNTP, Asp604, Ser661 and Asn670 were identified which can form H-bond network with 2'-OH group. Docking study revealed that Dasabuvir can potentially inhibit MnRdRp. The study concluded that the overall structure and function of MnRdRp are similar to Flaviviridae polymerases and their inhibitors can work against this enzyme.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Gulshan Kumar
- College of Fisheries Science Gunla, Birsa Agricultural University, Ranchi, Jharkhand, India
| | - A K Singh
- College of Fisheries Science Gunla, Birsa Agricultural University, Ranchi, Jharkhand, India
| | - Deepak Agarwal
- TNJFU, Institute of Fisheries Post Graduate Studies, OMR, Chennai, Tamil Nadu, India
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17
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Du R, Cui Q, Chen Z, Zhao X, Lin X, Rong L. Revisiting influenza A virus life cycle from a perspective of genome balance. Virol Sin 2023; 38:1-8. [PMID: 36309307 PMCID: PMC10006207 DOI: 10.1016/j.virs.2022.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
Influenza A virus (IAV) genome comprises eight negative-sense RNA segments, of which the replication is well orchestrated and the delicate balance of multiple segments are dynamically regulated throughout IAV life cycle. However, previous studies seldom discuss these balances except for functional hemagglutinin-neuraminidase balance that is pivotal for both virus entry and release. Therefore, we attempt to revisit IAV life cycle by highlighting the critical role of "genome balance". Moreover, we raise a "balance regression" model of IAV evolution that the virus evolves to rebalance its genome after reassortment or interspecies transmission, and direct a "balance compensation" strategy to rectify the "genome imbalance" as a result of artificial modifications during creation of recombinant IAVs. This review not only improves our understanding of IAV life cycle, but also facilitates both basic and applied research of IAV in future.
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Affiliation(s)
- Ruikun Du
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China; Qingdao Academy of Chinese Medicinal Sciences, Shandong University of Traditional Chinese Medicine, Qingdao, 266122, China.
| | - Qinghua Cui
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China; Qingdao Academy of Chinese Medicinal Sciences, Shandong University of Traditional Chinese Medicine, Qingdao, 266122, China
| | - Zinuo Chen
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Xiujuan Zhao
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Xiaojing Lin
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Lijun Rong
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, 60612, USA.
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18
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Malet H, Williams HM, Cusack S, Rosenthal M. The mechanism of genome replication and transcription in bunyaviruses. PLoS Pathog 2023; 19:e1011060. [PMID: 36634042 PMCID: PMC9836281 DOI: 10.1371/journal.ppat.1011060] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Bunyaviruses are negative sense, single-strand RNA viruses that infect a wide range of vertebrate, invertebrate and plant hosts. WHO lists three bunyavirus diseases as priority diseases requiring urgent development of medical countermeasures highlighting their high epidemic potential. While the viral large (L) protein containing the RNA-dependent RNA polymerase is a key enzyme in the viral replication cycle and therefore a suitable drug target, our knowledge on the structure and activities of this multifunctional protein has, until recently, been very limited. However, in the last few years, facilitated by the technical advances in the field of cryogenic electron microscopy, many structures of bunyavirus L proteins have been solved. These structures significantly enhance our mechanistic understanding of bunyavirus genome replication and transcription processes and highlight differences and commonalities between the L proteins of different bunyavirus families. Here, we provide a review of our current understanding of genome replication and transcription in bunyaviruses with a focus on the viral L protein. Further, we compare within bunyaviruses and with the related influenza virus polymerase complex and highlight open questions.
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Affiliation(s)
- Hélène Malet
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Institut Universitaire de France (IUF), Paris, France
| | - Harry M. Williams
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
| | | | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
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19
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Banerjee S, De A, Kedia N, Bhakta K, Wang L, Bhattacharjee B, Mondal A. The Species-Specific 282 Residue in the PB2 Subunit of the Polymerase Regulates RNA Synthesis and Replication of Influenza A Viruses Infecting Bat and Nonbat Hosts. J Virol 2022; 96:e0219021. [PMID: 35044213 PMCID: PMC8906409 DOI: 10.1128/jvi.02190-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 11/20/2022] Open
Abstract
Bat influenza viruses are genetically distant from classical influenza A viruses (IAVs) and show distinct functional differences in their surface antigens. Nevertheless, any comparative analyses between bat and classical IAV RNA polymerases or their specific subunits are yet to be performed. In this work, we have identified signature residues present in the bat influenza virus polymerase which are responsible for its altered fitness in comparison to the classical IAVs. Through comparative sequence and structural analysis, we have identified specific positions in the PB2 subunit of the polymerase, with differential amino acid preferences among bat and nonbat IAVs. Functional screening helped us to focus upon the previously uncharacterized PB2-282 residue, which is serine in bat virus but harbors highly conserved glutamic acid in classical IAVs. Introduction of E282S mutation in the human-adapted PB2 (influenza A/H1N1/WSN/1933) drastically reduces polymerase activity and replication efficiency of the virus in human, bat, and canine cells. Interestingly, this newly identified PB2-282 residue within an evolutionary conserved "S-E-S" motif, present across different genera of influenza viruses and serving as a key regulator of RNA synthesis activity of the polymerase. In contrast, bat influenza viruses harbor an atypical "S-S-T" motif at the same position of PB2, alteration of which with the human-like "S-E-T" motif significantly enhances its (H17N10/Guatemala/164/2009) polymerase activity in human cells. Together, our data indicate that the PB2-S282 residue may serve as an inherent restriction element of the bat virus polymerase, limiting its activity in other host species. IMPORTANCE Influenza A viruses are known for their ability to perform cross-species transmission, facilitated by amino acid alterations either in the surface antigen hemagglutinin (HA) or in the polymerase subunit PB2. Recent isolation of influenza A-like viruses from bats raised concern about their epizootic and zoonotic potential. Here, we identify a novel species-specific signature present within the influenza virus polymerase that may serve as a key factor in adaptation of influenza viruses from bat to nonbat host species. The PB2-282 residue, which harbors a highly conserved glutamic acid for influenza viruses across all genera (A, B, C, and D), encompasses an atypical serine in the case of bat influenza viruses. Our data show that the human-adapted polymerase, harboring a bat-specific signature (PB2-S282,) performs poorly, while bat PB2 protein, harboring a human-specific signature (PB2-E282), shows increased fitness in human cells.
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Affiliation(s)
- Saptarshi Banerjee
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Aratrika De
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Nandita Kedia
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
| | - Koustav Bhakta
- Department of Biochemistry, Bose Institute, Kolkata, West Bengal, India
| | - Linfa Wang
- Duke-NUS Medical School, Singapore City, Singapore
| | - Bornali Bhattacharjee
- Amity Institute of Biotechnology, Amity University Kolkata, Kolkata, West Bengal, India
| | - Arindam Mondal
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India
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20
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The C-terminal domains of the PB2 subunit of the influenza A virus RNA polymerase directly interact with cellular GTPase Rab11a. J Virol 2022; 96:e0197921. [PMID: 35019720 PMCID: PMC8906434 DOI: 10.1128/jvi.01979-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus (IAV) contains a segmented RNA genome that is transcribed and replicated by the viral RNA polymerase in the cell nucleus. Replicated RNA segments are assembled with viral polymerase and oligomeric nucleoprotein into viral ribonucleoprotein (vRNP) complexes which are exported from the nucleus and transported across the cytoplasm to be packaged into progeny virions. Host GTPase Rab11a associated with recycling endosomes is believed to contribute to this process by mediating the cytoplasmic transport of vRNPs. However, how vRNPs interact with Rab11a remains poorly understood. In this study, we utilised a combination of biochemical, proteomic, and biophysical approaches to characterise the interaction between the viral polymerase and Rab11a. Using pull-down assays we show that vRNPs but not cRNPs from infected cell lysates bind to Rab11a. We also show that the viral polymerase directly interacts with Rab11a and that the C-terminal two thirds of the PB2 polymerase subunit (PB2-C) comprising the cap-binding, mid-link, 627 and nuclear localization signal (NLS) domains mediate this interaction. Small-angle X-ray scattering (SAXS) experiments confirmed that PB2-C associates with Rab11a in solution forming a compact folded complex with a 1:1 stoichiometry. Furthermore, we demonstrate that the switch I region of Rab11a, that has been shown to be important for binding Rab11 family interacting proteins (Rab11-FIPs), is also important for PB2-C binding suggesting that IAV polymerase and Rab11-FIPs compete for the same binding site. Our findings expand our understanding of the interaction between the IAV polymerase and Rab11a in the cytoplasmic transport of vRNPs. Importance The influenza virus RNA genome segments are replicated in the cell nucleus and are assembled into viral ribonucleoprotein (vRNP) complexes with viral RNA polymerase and nucleoprotein (NP). Replicated vRNPs need to be exported from the nucleus and trafficked across the cytoplasm to the cell membrane where virion assembly takes place. The host GTPase Rab11a plays a role in vRNP trafficking. In this study we show that the viral polymerase directly interacts with Rab11a mediating the interaction between vRNPs and Rab11a. We map this interaction to the C-terminal domains of the PB2 polymerase subunit and the switch I region of Rab11a. Identifying the exact site of Rab11a binding on the viral polymerase could uncover a novel target site for the development of an influenza antiviral drug.
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21
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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: 12] [Impact Index Per Article: 6.0] [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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22
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Chiem K, Nogales A, Martinez-Sobrido L. Generation, Characterization, and Applications of Influenza A Reporter Viruses. Methods Mol Biol 2022; 2524:249-268. [PMID: 35821477 DOI: 10.1007/978-1-0716-2453-1_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Secondary experimental procedures such as immunostaining have been utilized to study wild-type influenza A viruses (IAV) but are inadequate to rapidly determine the virus in infected cells or for the high-throughput screening (HTS) of antivirals or neutralizing antibodies. Reverse genetics approaches have allowed the generation of recombinant IAV expressing bioluminescent (BL) reporters or fluorescent proteins (FPs). These approaches can easily track viral infections in cultured cells and in validated animal models of infection using in vivo imaging systems (IVIS). Here, we describe the experimental procedures to generate recombinant monomeric (m)Cherry-expressing influenza A/Puerto Rico/8/34 (PR8-mCherry) H1N1 by altering the non-structural (NS) vRNA segment and its use in mCherry-based microneutralization assays to assess antivirals and neutralizing antibodies. The experimental procedures could be used for the generation of other recombinant influenza virus types (e.g., influenza B) or IAV subtypes (e.g., H3N2) expressing mCherry or other BL reporters or FPs from the NS or other vRNA segment. These recombinant reporter-expressing viruses represent an excellent toolbox for the identification of prophylactics or therapeutics for the treatment of influenza viral infections in HTS settings as well as to study different aspects related with the biology of influenza viruses and/or its interaction with the host.
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Affiliation(s)
- Kevin Chiem
- Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Aitor Nogales
- Center for Animal Health Research, INIA-CISA/CSIC, Madrid, Spain.
| | - Luis Martinez-Sobrido
- Texas Biomedical Research Institute, San Antonio, TX, USA.
- Department of Internal Research, Texas Biomedical Research Institute, San Antonio, TX, USA.
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23
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Naudi-Fabra S, Blackledge M, Milles S. Synergies of Single Molecule Fluorescence and NMR for the Study of Intrinsically Disordered Proteins. Biomolecules 2021; 12:biom12010027. [PMID: 35053175 PMCID: PMC8773649 DOI: 10.3390/biom12010027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/19/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
Single molecule fluorescence and nuclear magnetic resonance spectroscopy (NMR) are two very powerful techniques for the analysis of intrinsically disordered proteins (IDPs). Both techniques have individually made major contributions to deciphering the complex properties of IDPs and their interactions, and it has become evident that they can provide very complementary views on the distance-dynamics relationships of IDP systems. We now review the first approaches using both NMR and single molecule fluorescence to decipher the molecular properties of IDPs and their interactions. We shed light on how these two techniques were employed synergistically for multidomain proteins harboring intrinsically disordered linkers, for veritable IDPs, but also for liquid–liquid phase separated systems. Additionally, we provide insights into the first approaches to use single molecule Förster resonance energy transfer (FRET) and NMR for the description of multiconformational models of IDPs.
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24
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Sreenivasan CC, Sheng Z, Wang D, Li F. Host Range, Biology, and Species Specificity of Seven-Segmented Influenza Viruses-A Comparative Review on Influenza C and D. Pathogens 2021; 10:1583. [PMID: 34959538 PMCID: PMC8704295 DOI: 10.3390/pathogens10121583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 02/06/2023] Open
Abstract
Other than genome structure, influenza C (ICV), and D (IDV) viruses with seven-segmented genomes are biologically different from the eight-segmented influenza A (IAV), and B (IBV) viruses concerning the presence of hemagglutinin-esterase fusion protein, which combines the function of hemagglutinin and neuraminidase responsible for receptor-binding, fusion, and receptor-destroying enzymatic activities, respectively. Whereas ICV with humans as primary hosts emerged nearly 74 years ago, IDV, a distant relative of ICV, was isolated in 2011, with bovines as the primary host. Despite its initial emergence in swine, IDV has turned out to be a transboundary bovine pathogen and a broader host range, similar to influenza A viruses (IAV). The receptor specificities of ICV and IDV determine the host range and the species specificity. The recent findings of the presence of the IDV genome in the human respiratory sample, and high traffic human environments indicate its public health significance. Conversely, the presence of ICV in pigs and cattle also raises the possibility of gene segment interactions/virus reassortment between ICV and IDV where these viruses co-exist. This review is a holistic approach to discuss the ecology of seven-segmented influenza viruses by focusing on what is known so far on the host range, seroepidemiology, biology, receptor, phylodynamics, species specificity, and cross-species transmission of the ICV and IDV.
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Affiliation(s)
- Chithra C. Sreenivasan
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
| | - Zizhang Sheng
- Aaron Diamond AIDS Research Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA;
| | - Dan Wang
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
| | - Feng Li
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
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25
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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: 2.7] [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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26
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Conformational changes in Lassa virus L protein associated with promoter binding and RNA synthesis activity. Nat Commun 2021; 12:7018. [PMID: 34857749 PMCID: PMC8639829 DOI: 10.1038/s41467-021-27305-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/08/2021] [Indexed: 11/08/2022] Open
Abstract
Lassa virus is endemic in West Africa and can cause severe hemorrhagic fever. The viral L protein transcribes and replicates the RNA genome via its RNA-dependent RNA polymerase activity. Here, we present nine cryo-EM structures of the L protein in the apo-, promoter-bound pre-initiation and active RNA synthesis states. We characterize distinct binding pockets for the conserved 3' and 5' promoter RNAs and show how full-promoter binding induces a distinct pre-initiation conformation. In the apo- and early elongation states, the endonuclease is inhibited by two distinct L protein peptides, whereas in the pre-initiation state it is uninhibited. In the early elongation state, a template-product duplex is bound in the active site cavity together with an incoming non-hydrolysable nucleotide and the full C-terminal region of the L protein, including the putative cap-binding domain, is well-ordered. These data advance our mechanistic understanding of how this flexible and multifunctional molecular machine is activated.
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27
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Abstract
Rift Valley fever virus (RVFV) belongs to the order Bunyavirales and is the type species of genus Phlebovirus, which accounts for over 50% of family Phenuiviridae species. RVFV is mosquito-borne and causes severe diseases in both humans and livestock, and consists of three segments (S, M, L) in the genome. The L segment encodes an RNA-dependent RNA polymerase (RdRp, L protein) that is responsible for facilitating the replication and transcription of the virus. It is essential for the virus and has multiple drug targets. Here, we established an expression system and purification procedures for full-length L protein, which is composed of an endonuclease domain, RdRp domain, and cap-binding domain. A cryo-EM L protein structure was reported at 3.6 Å resolution. In this first L protein structure of genus Phlebovirus, the priming loop of RVFV L protein is distinctly different from those of other L proteins and undergoes large movements related to its replication role. Structural and biochemical analyses indicate that a single template can induce initiation of RNA synthesis, which is notably enhanced by 5' viral RNA. These findings help advance our understanding of the mechanism of RNA synthesis and provide an important basis for developing antiviral inhibitors. Importance The zoonosis RVF virus (RVFV) is one of the most serious arbovirus threats to both human and animal health. RNA-dependent RNA polymerase (RdRp) is a multifunctional enzyme catalyzing genome replication as well as viral transcription, so the RdRp is essential for studying the virus and has multiple drug targets. In our study, we report the structure of RVFV L protein at 3.6 Å resolution by cryo-EM. This is the first L protein structure of genus Phlebovirus. Strikingly, a single template can initiate RNA replication. The structure and assays provide a comprehensive and in-depth understanding of the catalytic and substrate recognition mechanism of RdRp.
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28
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Abstract
Influenza polymerase (FluPol) plays a key role in the viral infection cycle by transcribing and replicating the viral genome. FluPol is a multifunctional, heterotrimeric enzyme with cap-binding, endonuclease, RNA-dependent RNA polymerase and polyadenylation activities. It performs its functions in the context of the viral ribonucleoprotein particle (RNP), wherein the template viral RNA is coated by multiple copies of viral nucleoprotein. Moreover, it interacts with a number of host proteins that are essential cofactors and, consequently, adaptive mutations in the polymerase are required for crossing the avian-human species barrier. In this review, we show how mechanistic understanding of how FluPol performs its multiple functions has greatly advanced over the last decade through determination of high-resolution structures by X-ray crystallography and cryo-electron microscopy. These have revealed not only the detailed architecture of FluPol but highlighted the remarkably conformational flexibility that is inherent to its functioning as a dynamic RNA synthesis machine. Structural studies are also underpinning current attempts to develop next-generation anti-influenza drugs that directly target FluPol.
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Affiliation(s)
- Joanna M Wandzik
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
| | - Tomas Kouba
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
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29
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Xu X, Zhang L, Chu JTS, Wang Y, Chin AWH, Chong TH, Dai Z, Poon LLM, Cheung PPH, Huang X. A novel mechanism of enhanced transcription activity and fidelity for influenza A viral RNA-dependent RNA polymerase. Nucleic Acids Res 2021; 49:8796-8810. [PMID: 34379778 PMCID: PMC8421151 DOI: 10.1093/nar/gkab660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/13/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
During RNA elongation, the influenza A viral (IAV) RNA-dependent RNA polymerase (RdRp) residues in the active site interact with the triphosphate moiety of nucleoside triphosphate (NTP) for catalysis. The molecular mechanisms by which they control the rate and fidelity of NTP incorporation remain elusive. Here, we demonstrated through enzymology, virology and computational approaches that the R239 and K235 in the PB1 subunit of RdRp are critical to controlling the activity and fidelity of transcription. Contrary to common beliefs that high-fidelity RdRp variants exert a slower incorporation rate, we discovered a first-of-its-kind, single lysine-to-arginine mutation on K235 exhibited enhanced fidelity and activity compared with wild-type. In particular, we employed a single-turnover NTP incorporation assay for the first time on IAV RdRp to show that K235R mutant RdRp possessed a 1.9-fold increase in the transcription activity of the cognate NTP and a 4.6-fold increase in fidelity compared to wild-type. Our all-atom molecular dynamics simulations further elucidated that the higher activity is attributed to the shorter distance between K235R and the triphosphate moiety of NTP compared with wild-type. These results provide novel insights into NTP incorporation and fidelity control mechanisms, which lay the foundation for the rational design of IAV vaccine and antiviral targets.
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Affiliation(s)
- Xinzhou Xu
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Julie Tung Sem Chu
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yuqing Wang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Alex Wing Hong Chin
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Centre for Immunity and Infection, Hong Kong Science Park, Hong Kong, China
| | - Tin Hang Chong
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Zixi Dai
- Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Leo Lit Man Poon
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Centre for Immunity and Infection, Hong Kong Science Park, Hong Kong, China
| | - Peter Pak-Hang Cheung
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.,Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China.,Li Ka Shing Institute of Health Sciences, Li Ka Shing Medical Sciences Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xuhui Huang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
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30
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Ultrastructure of influenza virus ribonucleoprotein complexes during viral RNA synthesis. Commun Biol 2021; 4:858. [PMID: 34244608 PMCID: PMC8271009 DOI: 10.1038/s42003-021-02388-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/23/2021] [Indexed: 11/16/2022] Open
Abstract
The single-stranded, negative-sense, viral genomic RNA (vRNA) of influenza A virus is encapsidated by viral nucleoproteins (NPs) and an RNA polymerase to form a ribonucleoprotein complex (vRNP) with a helical, rod-shaped structure. The vRNP is responsible for transcription and replication of the vRNA. However, the vRNP conformation during RNA synthesis is not well understood. Here, using high-speed atomic force microscopy and cryo-electron microscopy, we investigated the native structure of influenza A vRNPs during RNA synthesis in vitro. Two distinct types of vRNPs were observed in association with newly synthesized RNAs: an intact, helical rod-shaped vRNP connected with a folded RNA and a deformed vRNP associated with a looped RNA. Interestingly, the looped RNA was a double-stranded RNA, which likely comprises a nascent RNA and the template RNA detached from NPs of the vRNP. These results suggest that while some vRNPs keep their helical structures during RNA synthesis, for the repeated cycle of RNA synthesis, others accidentally become structurally deformed, which likely results in failure to commence or continue RNA synthesis. Thus, our findings provide the ultrastructural feature of vRNPs during RNA synthesis. Nakano et al. use high-speed AFM and cryo-EM to study influenza virus RNA synthesis in vitro. They observe the synthesis of two types of RNA: folded single stranded RNA associated to an intact viral ribonucleoprotein (vRNP) and looped, double stranded RNA associated with a partially rearranged vRNP structure.
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31
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Kang H, Cong J, Wang C, Ji W, Xin Y, Qian Y, Li X, Chen Y, Rao Z. Structural basis for recognition and regulation of arenavirus polymerase L by Z protein. Nat Commun 2021; 12:4134. [PMID: 34226547 PMCID: PMC8257661 DOI: 10.1038/s41467-021-24458-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/21/2021] [Indexed: 02/05/2023] Open
Abstract
Junin virus (JUNV) causes Argentine hemorrhagic fever, a debilitating human disease of high mortality rates and a great risk to public health worldwide. Studying the L protein that replicates and transcribes the genome of JUNV, and its regulator Z protein should provide critical clues to identify therapeutic targets for disrupting the life cycle of JUNV. Here we report the 3.54 Å cryo-EM structure of the JUNV L protein complexed with regulator Z protein. JUNV L structure reveals a conserved architecture containing signature motifs found in other L proteins. Structural analysis shows that L protein is regulated by binding of Z protein at the RNA product exit site. Based on these findings, we propose a model for the role of Z protein as a switch to turn on/off the viral RNA synthesis via its interaction with L protein. Our work unveils the mechanism of JUNV transcription, replication and regulation, which provides a framework for the rational design of antivirals for combating viral infections. Junin virus (JUNV) causes Argentine hemorrhagic fever and encodes the large protein (L) of the RNA dependent RNA polymerase (RdRp) and its regulator, the matrix zinc-binding protein (Z). Here, the authors present the 3.54 Å cryo-EM structure of the complex of JUNV L with Z, and they propose a model of how JUNV L is regulated by Z during the viral life cycle and RNA synthesis.
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Affiliation(s)
- Huiling Kang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Biotherapy, West China Hospital, Collaborative Innovation Center for Biotherapy, Sichuan University, Chengdu, China
| | - Jingyuan Cong
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chenlong Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wenxin Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yuhui Xin
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ying Qian
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xuemei Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
| | - Yutao Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
| | - Zihe Rao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Laboratory of Structural Biology, School of Medicine, Tsinghua University, Beijing, China
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32
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Waters K, Wan HJ, Han L, Xue J, Ykema M, Tao YJ, Wan XF. Variations outside the conserved motifs of PB1 catalytic active site may affect replication efficiency of the RNP complex of influenza A virus. Virology 2021; 559:145-155. [PMID: 33887645 PMCID: PMC8579824 DOI: 10.1016/j.virol.2021.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/31/2021] [Accepted: 04/05/2021] [Indexed: 12/24/2022]
Abstract
PB1 functions as the catalytic subunit of influenza virus RNA polymerase complex and plays an essential role in viral RNA transcription and replication. To determine plasticity in the PB1 enzymatic site and map catalytically important residues, 658 mutants were constructed, each with one to seven mutations in the enzymatic site of PB1. The polymerase activities of these mutants were quantified using a minigenome assay, and polymerase activity-associated residues were identified using sparse learning. Results showed that polymerase activities are affected by the residues not only within the conserved motifs, but also across the inter-motif regions of PB1, and the latter are primarily located at the base of the palm domain, a region that is conserved in avian PB1 but with high sequence diversity in swine PB1. Our results suggest that mutations outside the PB1 conserved motifs may affect RNA replication and could be associated with influenza virus host adaptation.
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Affiliation(s)
- Kaitlyn Waters
- Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Hamilton J Wan
- Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Lei Han
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Jianli Xue
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Matthew Ykema
- Department of BioSciences, Rice University, Houston, TX, 77251, USA
| | - Yizhi J Tao
- Department of BioSciences, Rice University, Houston, TX, 77251, USA
| | - Xiu-Feng Wan
- Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA; Department of Electrical Engineering & Computer Science, College of Engineering, University of Missouri, Columbia, MO, USA.
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33
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Li X, Liang Z, Gan J, Lu L. Epidemic situation of the complex seasonality of imported influenza A and B virus transmission in Guangxi ports of China. Turk J Med Sci 2021; 51:1021-1026. [PMID: 33237658 PMCID: PMC8283440 DOI: 10.3906/sag-2008-63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 11/21/2020] [Indexed: 11/28/2022] Open
Abstract
Background/aim Analysis of the characteristics of influenza virus in imported cases in Guangxi province of China. Materials and methods Throat swabs of imported cases with influenza-like symptoms were detected by real-time PCR from July 2016 to December 2019. Results 1292 laboratory detections of influenza were reported in 3974 influenza-like cases, of which 71.67% (926) were influenza A. The ratio of test positive was 32.82%. The proportion of detections of influenza B was 28.33% (366). A total of 70.51% of the cases mostly came from Vietnam (911). A total of 86.76% (1121) of the cases were imported from Dongxing Port, Nanning Airport, and Pingxiang Port. There was no statistical difference in all age groups. At the same time, 3 of the untyped A-type specimens were sequenced by next-generation sequencing. Among them, the sequences of 2 specimens from Vietnam had high homology with the influenza strain H3N2 in Hong Kong in 2017. The specimen sequence from Thailand is highly homologous to the influenza pandemic strain H1N1 in Brisbane, Australia in 2018. Conclusion Imported influenza cases in Guangxi have occurred throughout the year, with higher numbers in winter and spring. The cases mostly came from Vietnam with influenza A. Relevant measures should be taken to control the further spread of the virus.
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Affiliation(s)
- Xiangjuan Li
- Guangxi International Travel Healthcare Center, Nanning Customs Port Clinic, Nanning, Guangxi, China
| | - Zhongping Liang
- Guangxi International Travel Healthcare Center, Nanning Customs Port Clinic, Nanning, Guangxi, China
| | - Jie Gan
- Guangxi International Travel Healthcare Center, Nanning Customs Port Clinic, Nanning, Guangxi, China
| | - Lingmin Lu
- Guangxi International Travel Healthcare Center, Nanning Customs Port Clinic, Nanning, Guangxi, China
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Comprehensive Profiling of Mutations to Influenza Virus PB2 That Confer Resistance to the Cap-Binding Inhibitor Pimodivir. Viruses 2021; 13:v13071196. [PMID: 34206520 PMCID: PMC8310130 DOI: 10.3390/v13071196] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/06/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
Antivirals are used not only in the current treatment of influenza but are also stockpiled as a first line of defense against novel influenza strains for which vaccines have yet to be developed. Identifying drug resistance mutations can guide the clinical deployment of the antiviral and can additionally define the mechanisms of drug action and drug resistance. Pimodivir is a first-in-class inhibitor of the polymerase basic protein 2 (PB2) subunit of the influenza A virus polymerase complex. A number of resistance mutations have previously been identified in treated patients or cell culture. Here, we generate a complete map of the effect of all single-amino-acid mutations to an avian PB2 on resistance to pimodivir. We identified both known and novel resistance mutations not only in the previously implicated cap-binding and mid-link domains, but also in the N-terminal domain. Our complete map of pimodivir resistance thus enables the evaluation of whether new viral strains contain mutations that will confer pimodivir resistance.
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Massari S, Desantis J, Nizi MG, Cecchetti V, Tabarrini O. Inhibition of Influenza Virus Polymerase by Interfering with Its Protein-Protein Interactions. ACS Infect Dis 2021; 7:1332-1350. [PMID: 33044059 PMCID: PMC8204303 DOI: 10.1021/acsinfecdis.0c00552] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Influenza (flu) virus is a serious threat to global health with the potential to generate devastating pandemics. The availability of broad spectrum antiviral drugs is an unequaled weapon during pandemic events, especially when a vaccine is still not available. One of the most promising targets for the development of new antiflu therapeutics is the viral RNA-dependent RNA polymerase (RdRP). The assembly of the flu RdRP heterotrimeric complex from the individual polymerase acidic protein (PA), polymerase basic protein 1 (PB1), and polymerase basic protein 2 (PB2) subunits is a prerequisite for RdRP functions, such as mRNA synthesis and genome replication. In this Review, we report the known protein-protein interactions (PPIs) occurring by RdRP that could be disrupted by small molecules and analyze their benefits and drawbacks as drug targets. An overview of small molecules able to interfere with flu RdRP functions exploiting the PPI inhibition approach is described. In particular, an update on the most recent inhibitors targeting the well-consolidated RdRP PA-PB1 subunit heterodimerization is mainly reported, together with pioneer inhibitors targeting other virus-virus or virus-host interactions involving RdRP subunits. As demonstrated by the PA-PB1 interaction inhibitors discussed herein, the inhibition of flu RdRP functions by PPI disrupters clearly represents a valid means to identify compounds endowed with a broad spectrum of action and a reduced propensity to develop drug resistance, which are the main issues of antiviral drugs.
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Affiliation(s)
- Serena Massari
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Jenny Desantis
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy
| | - Maria Giulia Nizi
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Oriana Tabarrini
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
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Takashita E. Influenza Polymerase Inhibitors: Mechanisms of Action and Resistance. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a038687. [PMID: 32122918 PMCID: PMC8091960 DOI: 10.1101/cshperspect.a038687] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The influenza virus RNA-dependent RNA polymerase is highly conserved among influenza A, B, C, and D viruses. It comprises three subunits: polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2), and polymerase acidic protein (PA) in influenza A and B viruses or polymerase 3 protein (P3) in influenza C and D viruses. Because this polymerase is essential for influenza virus replication, it has been considered as a target for antiviral agents. Recently, several polymerase inhibitors that target each subunit have been developed. This review discusses the mechanism of action, antiviral activity, and emergence of resistance to three inhibitors approved for the treatment of influenza or in late-phase clinical trials: the PB1 inhibitor favipiravir, the PB2 inhibitor pimodivir, and the PA inhibitor baloxavir marboxil.
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Affiliation(s)
- Emi Takashita
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo 208-0011, Japan
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37
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Te Velthuis AJW, Grimes JM, Fodor E. Structural insights into RNA polymerases of negative-sense RNA viruses. Nat Rev Microbiol 2021; 19:303-318. [PMID: 33495561 PMCID: PMC7832423 DOI: 10.1038/s41579-020-00501-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2020] [Indexed: 01/29/2023]
Abstract
RNA viruses include many important human and animal pathogens, such as the influenza viruses, respiratory syncytial virus, Ebola virus, measles virus and rabies virus. The genomes of these viruses consist of single or multiple RNA segments that assemble with oligomeric viral nucleoprotein into ribonucleoprotein complexes. Replication and transcription of the viral genome is performed by ~250-450 kDa viral RNA-dependent RNA polymerases that also contain capping or cap-snatching activity. In this Review, we compare recent high-resolution X-ray and cryoelectron microscopy structures of RNA polymerases of negative-sense RNA viruses with segmented and non-segmented genomes, including orthomyxoviruses, peribunyaviruses, phenuiviruses, arenaviruses, rhabdoviruses, pneumoviruses and paramyxoviruses. In addition, we discuss how structural insights into these enzymes contribute to our understanding of the molecular mechanisms of viral transcription and replication, and how we can use these insights to identify targets for antiviral drug design.
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Affiliation(s)
- Aartjan J W Te Velthuis
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK.
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
| | - Jonathan M Grimes
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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38
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Weis S, te Velthuis AJW. Influenza Virus RNA Synthesis and the Innate Immune Response. Viruses 2021; 13:v13050780. [PMID: 33924859 PMCID: PMC8146608 DOI: 10.3390/v13050780] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 04/25/2021] [Accepted: 04/25/2021] [Indexed: 12/25/2022] Open
Abstract
Infection with influenza A and B viruses results in a mild to severe respiratory tract infection. It is widely accepted that many factors affect the severity of influenza disease, including viral replication, host adaptation, innate immune signalling, pre-existing immunity, and secondary infections. In this review, we will focus on the interplay between influenza virus RNA synthesis and the detection of influenza virus RNA by our innate immune system. Specifically, we will discuss the generation of various RNA species, host pathogen receptors, and host shut-off. In addition, we will also address outstanding questions that currently limit our knowledge of influenza virus replication and host adaption. Understanding the molecular mechanisms underlying these factors is essential for assessing the pandemic potential of future influenza virus outbreaks.
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Virtual Screening and Molecular Docking Studies for Discovery of Potential RNA-Dependent RNA Polymerase Inhibitors. CRYSTALS 2021. [DOI: 10.3390/cryst11050471] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The current COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Globally, this pandemic has affected over 111 million individuals and posed many health and economic challenges. Much research effort is dedicated to discovering new treatments to address the associated challenges and restrict the spread of SARS-CoV-2. Since SARS-CoV-2 is a positive-strand RNA virus, its replication requires the viral RNA-dependent RNA polymerase (RdRp) enzyme. In this study, we report the discovery of new potential RdRp enzyme inhibitors based on computer modeling and simulation methodologies. The antiviral ZINC database was utilized for covalent docking virtual screening followed by molecular inter-action analyses based on reported hot spots within the RdRp binding pocket (PDB: 7BV2). Eleven molecules, ZINC000014944915, ZINC000027556215, ZINC000013556344, ZINC000003589958, ZINC000003833965, ZINC000001642252, ZINC000028525778, ZINC000027557701, ZINC000013781295, ZINC000001651128 and ZINC000013473324, were shown to have the highest binding interactions. These molecules were further assessed by molecular dynamics (MD) simu-lations and absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies. The results showed that all 11 molecules except ZINC000027557701 formed stable complexes with the viral RdRp and fell within the accepted ADMET parameters. The identified molecules can be used to design future potential RdRp inhibitors.
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40
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Fearns R. Negative‐strand RNA Viruses. Virology 2021. [DOI: 10.1002/9781119818526.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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41
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Tian L, Qiang T, Liang C, Ren X, Jia M, Zhang J, Li J, Wan M, YuWen X, Li H, Cao W, Liu H. RNA-dependent RNA polymerase (RdRp) inhibitors: The current landscape and repurposing for the COVID-19 pandemic. Eur J Med Chem 2021; 213:113201. [PMID: 33524687 PMCID: PMC7826122 DOI: 10.1016/j.ejmech.2021.113201] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/14/2020] [Accepted: 01/12/2021] [Indexed: 02/06/2023]
Abstract
The widespread nature of several viruses is greatly credited to their rapidly altering RNA genomes that enable the infection to persist despite challenges presented by host cells. Within the RNA genome of infections is RNA-dependent RNA polymerase (RdRp), which is an essential enzyme that helps in RNA synthesis by catalysing the RNA template-dependent development of phosphodiester bonds. Therefore, RdRp is an important therapeutic target in RNA virus-caused diseases, including SARS-CoV-2. In this review, we describe the promising RdRp inhibitors that have been launched or are currently in clinical studies for the treatment of RNA virus infections. Structurally, nucleoside inhibitors (NIs) bind to the RdRp protein at the enzyme active site, and nonnucleoside inhibitors (NNIs) bind to the RdRp protein at allosteric sites. By reviewing these inhibitors, more precise guidelines for the development of more promising anti-RNA virus drugs should be set, and due to the current health emergency, they will eventually be used for COVID-19 treatment.
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Affiliation(s)
- Lei Tian
- College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China; Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Taotao Qiang
- College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Chengyuan Liang
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China.
| | - Xiaodong Ren
- Medical College, Guizhou University, Guiyang, 550025, PR China.
| | - Minyi Jia
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Jiayun Zhang
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Jingyi Li
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Minge Wan
- School of Medicine and Pharmacy, Shaanxi University of Business & Commerce, Xi'an, 712046, PR China
| | - Xin YuWen
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Han Li
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Wenqiang Cao
- Zhuhai Jinan Selenium Source Nanotechnology Co., Ltd., Hengqin New Area, Zhuhai, 519030, PR China.
| | - Hong Liu
- Zhuhai Jinan Selenium Source Nanotechnology Co., Ltd., Hengqin New Area, Zhuhai, 519030, PR China.
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42
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Prediction and characterization of influenza virus polymerase inhibitors through blind docking and ligand based virtual screening. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114784] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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43
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PA Mutations Inherited during Viral Evolution Act Cooperatively To Increase Replication of Contemporary H5N1 Influenza Virus with an Expanded Host Range. J Virol 2020; 95:JVI.01582-20. [PMID: 33028722 PMCID: PMC7737735 DOI: 10.1128/jvi.01582-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/04/2020] [Indexed: 12/12/2022] Open
Abstract
Clade 2.2.1 avian influenza viruses (H5N1) are unique to Egypt and have caused the highest number of human H5N1 influenza cases worldwide, presenting a serious global public health threat. These viruses may have the greatest evolutionary potential for adaptation from avian hosts to human hosts. Using a comprehensive phylogenetic approach, we identified several novel clade 2.2.1 virus polymerase mutations that increased viral replication in vitro in human cells and in vivo in mice. These mutations were in the polymerase PA subunit and acted cooperatively with the E627K mutation in the PB2 polymerase subunit to provide higher replication in contemporary clade 2.2.1.2 viruses than in ancestral clade 2.2.1 viruses. These data indicated that ongoing clade 2.2.1 dissemination in the field has driven PA mutations to modify viral replication to enable host range expansion, with a higher public health risk for humans. Adaptive mutations and/or reassortments in avian influenza virus polymerase subunits PA, PB1, and PB2 are one of the major factors enabling the virus to overcome the species barrier to infect humans. The majority of human adaptation polymerase mutations have been identified in PB2; fewer adaptation mutations have been characterized in PA and PB1. Clade 2.2.1 avian influenza viruses (H5N1) are unique to Egypt and generally carry the human adaptation PB2-E627K substitution during their dissemination in nature. In this study, we identified other human adaptation polymerase mutations by analyzing phylogeny-associated PA mutations that H5N1 clade 2.2.1 viruses have accumulated during their evolution in the field. This analysis identified several PA mutations that produced increased replication by contemporary clade 2.2.1.2 viruses in vitro in human cells and in vivo in mice compared to ancestral clade 2.2.1 viruses. The PA mutations acted cooperatively to increase viral polymerase activity and replication in both avian and human cells, with the effect being more prominent in human cells at 33°C than at 37°C. These results indicated that PA mutations have a role in establishing contemporary clade 2.2.1.2 virus infections in poultry and in adaptation to infect mammals. Our study provided data on the mechanism for PA mutations to accumulate during avian influenza virus evolution and extend the viral host range. IMPORTANCE Clade 2.2.1 avian influenza viruses (H5N1) are unique to Egypt and have caused the highest number of human H5N1 influenza cases worldwide, presenting a serious global public health threat. These viruses may have the greatest evolutionary potential for adaptation from avian hosts to human hosts. Using a comprehensive phylogenetic approach, we identified several novel clade 2.2.1 virus polymerase mutations that increased viral replication in vitro in human cells and in vivo in mice. These mutations were in the polymerase PA subunit and acted cooperatively with the E627K mutation in the PB2 polymerase subunit to provide higher replication in contemporary clade 2.2.1.2 viruses than in ancestral clade 2.2.1 viruses. These data indicated that ongoing clade 2.2.1 dissemination in the field has driven PA mutations to modify viral replication to enable host range expansion, with a higher public health risk for humans.
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44
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Carrique L, Fan H, Walker AP, Keown JR, Sharps J, Staller E, Barclay WS, Fodor E, Grimes JM. Host ANP32A mediates the assembly of the influenza virus replicase. Nature 2020; 587:638-643. [PMID: 33208942 PMCID: PMC7116770 DOI: 10.1038/s41586-020-2927-z] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 09/01/2020] [Indexed: 12/11/2022]
Abstract
Aquatic birds represent a vast reservoir from which new pandemic influenza A viruses can emerge1. Influenza viruses contain a negative-sense segmented RNA genome that is transcribed and replicated by the viral heterotrimeric RNA polymerase (FluPol) in the context of viral ribonucleoprotein complexes2,3. RNA polymerases of avian influenza A viruses (FluPolA) replicate viral RNA inefficiently in human cells because of species-specific differences in acidic nuclear phosphoprotein 32 (ANP32), a family of essential host proteins for FluPol activity4. Host-adaptive mutations, particularly a glutamic-acid-to-lysine mutation at amino acid residue 627 (E627K) in the 627 domain of the PB2 subunit, enable avian FluPolA to overcome this restriction and efficiently replicate viral RNA in the presence of human ANP32 proteins. However, the molecular mechanisms of genome replication and the interplay with ANP32 proteins remain largely unknown. Here we report cryo-electron microscopy structures of influenza C virus polymerase (FluPolC) in complex with human and chicken ANP32A. In both structures, two FluPolC molecules form an asymmetric dimer bridged by the N-terminal leucine-rich repeat domain of ANP32A. The C-terminal low-complexity acidic region of ANP32A inserts between the two juxtaposed PB2 627 domains of the asymmetric FluPolA dimer, suggesting a mechanism for how the adaptive PB2(E627K) mutation enables the replication of viral RNA in mammalian hosts. We propose that this complex represents a replication platform for the viral RNA genome, in which one of the FluPol molecules acts as a replicase while the other initiates the assembly of the nascent replication product into a viral ribonucleoprotein complex.
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Affiliation(s)
- Loïc Carrique
- Division of Structural Biology, University of Oxford, Oxford, UK
| | - Haitian Fan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Jeremy R Keown
- Division of Structural Biology, University of Oxford, Oxford, UK
| | - Jane Sharps
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Ecco Staller
- Section of Molecular Virology, Imperial College London, London, UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Wendy S Barclay
- Section of Molecular Virology, Imperial College London, London, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
| | - Jonathan M Grimes
- Division of Structural Biology, University of Oxford, Oxford, UK.
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, UK.
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45
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Fodor E, Te Velthuis AJW. Structure and Function of the Influenza Virus Transcription and Replication Machinery. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a038398. [PMID: 31871230 DOI: 10.1101/cshperspect.a038398] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transcription and replication of the influenza virus RNA genome is catalyzed by the viral heterotrimeric RNA-dependent RNA polymerase in the context of viral ribonucleoprotein (vRNP) complexes. Atomic resolution structures of the viral RNA synthesis machinery have offered insights into the initiation mechanisms of viral transcription and genome replication, and the interaction of the viral RNA polymerase with host RNA polymerase II, which is required for the initiation of viral transcription. Replication of the viral RNA genome by the viral RNA polymerase depends on host ANP32A, and host-specific sequence differences in ANP32A underlie the poor activity of avian influenza virus polymerases in mammalian cells. A failure to faithfully copy the viral genome segments can lead to the production of aberrant viral RNA products, such as defective interfering (DI) RNAs and mini viral RNAs (mvRNAs). Both aberrant RNA types have been implicated in innate immune responses against influenza virus infection. This review discusses recent insights into the structure-function relationship of the viral RNA polymerase and its role in determining host range and virulence.
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Affiliation(s)
- Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Aartjan J W Te Velthuis
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge CB2 2QQ, United Kingdom
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46
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Pagadala NS, Bhat R, Kumar D J, Landi A. Discovery of anti-influenza nucleoside triphosphates targeting the catalytic site of A/PR/8/34/H1N1 polymerase. Med Chem Res 2020; 29:1463-1477. [PMID: 32837136 PMCID: PMC7246003 DOI: 10.1007/s00044-020-02561-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/12/2020] [Indexed: 11/28/2022]
Abstract
In an effort to develop potent anti-influenza drugs that inhibit the activity of influenza virus RNA-dependent RNA polymerase (IAV RdRp), a database of nucleoside triphosphates with ~800 molecules were docked with the homology model of IAV RdRp from A/PR/8/34/H1N1 strain. Out of top 12 molecules that bind with higher affinities to the catalytic site of IAV RdRp above and below the PB1 priming loop, only seven molecules decreased the transcriptional activity of the viral RNA polymerase with an IC50 in the range of 0.09–3.58 µM. Molecular docking combining with experimental study indicated that the molecules with linear chain are more effective in inhibiting IAV RdRp replication than the molecules with V-shaped and are cyclic in nature. A correlation between ΔG and LogIC50 for these seven compounds resulted an R2 value of 0.73. Overall, these newly developed seven nucleoside triphosphates lay a strong foundation for the future development of a new therapeutics that can satisfy the Lipinski’s rule of five exhibiting high specificity to the catalytic site of influenza-A viruses.
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Affiliation(s)
- Nataraj Sekhar Pagadala
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1 Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB Canada
| | - Rakesh Bhat
- Precision Bio Laboratories, Edmonton, AB Canada
| | - Jagadeesh Kumar D
- Department of Biotechnology, Sir M. Visvesvaraya Institute of Technology, Bangalore, India
| | - Abdolamir Landi
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1 Canada
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB Canada
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Luo M, Terrell JR, Mcmanus SA. Nucleocapsid Structure of Negative Strand RNA Virus. Viruses 2020; 12:E835. [PMID: 32751700 PMCID: PMC7472042 DOI: 10.3390/v12080835] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022] Open
Abstract
Negative strand RNA viruses (NSVs) include many important human pathogens, such as influenza virus, Ebola virus, and rabies virus. One of the unique characteristics that NSVs share is the assembly of the nucleocapsid and its role in viral RNA synthesis. In NSVs, the single strand RNA genome is encapsidated in the linear nucleocapsid throughout the viral replication cycle. Subunits of the nucleocapsid protein are parallelly aligned along the RNA genome that is sandwiched between two domains composed of conserved helix motifs. The viral RNA-dependent-RNA polymerase (vRdRp) must recognize the protein-RNA complex of the nucleocapsid and unveil the protected genomic RNA in order to initiate viral RNA synthesis. In addition, vRdRp must continuously translocate along the protein-RNA complex during elongation in viral RNA synthesis. This unique mechanism of viral RNA synthesis suggests that the nucleocapsid may play a regulatory role during NSV replication.
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Affiliation(s)
- Ming Luo
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA; (J.R.T.); (S.A.M.)
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Molecular basis of host-adaptation interactions between influenza virus polymerase PB2 subunit and ANP32A. Nat Commun 2020; 11:3656. [PMID: 32694517 PMCID: PMC7374565 DOI: 10.1038/s41467-020-17407-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022] Open
Abstract
Avian influenza polymerase undergoes host adaptation in order to efficiently replicate in human cells. Adaptive mutants are localised on the C-terminal (627-NLS) domains of the PB2 subunit. In particular, mutation of PB2 residue 627 from E to K rescues polymerase activity in mammalian cells. A host transcription regulator ANP32A, comprising a long C-terminal intrinsically disordered domain (IDD), is responsible for this adaptation. Human ANP32A IDD lacks a 33 residue insertion compared to avian ANP32A, and this deletion restricts avian influenza polymerase activity. We used NMR to determine conformational ensembles of E627 and K627 forms of 627-NLS of PB2 in complex with avian and human ANP32A. Human ANP32A IDD transiently binds to the 627 domain, exploiting multivalency to maximise affinity. E627 interrupts the polyvalency of the interaction, an effect compensated by an avian-unique motif in the IDD. The observed binding mode is maintained in the context of heterotrimeric influenza polymerase, placing ANP32A in the immediate vicinity of known host-adaptive PB2 mutants. Avian influenza polymerase undergoes host adaptation in order to efficiently replicate in human cells. Here, the authors use NMR spectroscopy and quantitative ensemble modelling to describe the highly dynamic assemblies formed by the human-adapted or avian-adapted C-terminal domains with the respective ANP32A host proteins.
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Suzuki Y, Inoue T, Nishimura M, Kobayashi Y. Putative bundling signals incompatible between influenza C and D viruses. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Peng Q, Peng R, Yuan B, Zhao J, Wang M, Wang X, Wang Q, Sun Y, Fan Z, Qi J, Gao GF, Shi Y. Structural and Biochemical Characterization of the nsp12-nsp7-nsp8 Core Polymerase Complex from SARS-CoV-2. Cell Rep 2020; 31:107774. [PMID: 32531208 PMCID: PMC7260489 DOI: 10.1016/j.celrep.2020.107774] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/23/2020] [Accepted: 05/26/2020] [Indexed: 01/18/2023] Open
Abstract
The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has caused a huge number of human deaths. Currently, there are no specific drugs or vaccines available for this virus (SARS-CoV-2). The viral polymerase is a promising antiviral target. Here, we describe the near-atomic-resolution structure of the SARS-CoV-2 polymerase complex consisting of the nsp12 catalytic subunit and nsp7-nsp8 cofactors. This structure highly resembles the counterpart of SARS-CoV with conserved motifs for all viral RNA-dependent RNA polymerases and suggests a mechanism of activation by cofactors. Biochemical studies reveal reduced activity of the core polymerase complex and lower thermostability of individual subunits of SARS-CoV-2 compared with SARS-CoV. These findings provide important insights into RNA synthesis by coronavirus polymerase and indicate adaptation of SARS-CoV-2 toward humans with a relatively lower body temperature than the natural bat hosts. Cryo-EM structure of SARS-CoV-2 nsp12-nsp7-nsp8 core polymerase complex The core complex of SARS-CoV-2 has lower enzymatic activity than SARS-CoV SARS-CoV-2 nsp7-8-12 subunits are less thermostable than the SARS-CoV counterpart
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Affiliation(s)
- Qi Peng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ruchao Peng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bin Yuan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jingru Zhao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Min Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xixi Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Sun
- Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China; Center for Influenza Research and Early Warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Diseases (CEEID), Chinese Academy of Sciences, Beijing 100101, China
| | - George F Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China; Center for Influenza Research and Early Warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Diseases (CEEID), Chinese Academy of Sciences, Beijing 100101, China
| | - Yi Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of the Chinese Academy of Sciences, Beijing 100049, China; Center for Influenza Research and Early Warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Diseases (CEEID), Chinese Academy of Sciences, Beijing 100101, China; Chongqing Key Laboratory of Neurodegenerative Diseases, Chongqing General Hospital, University of the Chinese Academy of Sciences, Chongqing 400013, China; College of Basic Medicine, Jilin University, Changchun, Jilin 130021, China.
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