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Bai Y, Lei H, Song W, Shin SC, Wang J, Xiao B, Koçer ZA, Song MS, Webster R, Webby RJ, Wong SS, Zanin M. Amino acids in the polymerase complex of shorebird-isolated H1N1 influenza virus impact replication and host-virus interactions in mammalian models. Emerg Microbes Infect 2024; 13:2332652. [PMID: 38517705 PMCID: PMC11018082 DOI: 10.1080/22221751.2024.2332652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/15/2024] [Indexed: 03/24/2024]
Abstract
A diverse population of avian influenza A viruses (AIVs) are maintained in wild birds and ducks yet the zoonotic potential of AIVs in these environmental reservoirs and the host-virus interactions involved in mammalian infection are not well understood. In studies of a group of subtype H1N1 AIVs isolated from migratory wild birds during surveillance in North America, we previously identified eight amino acids in the polymerase genes PB2 and PB1 that were important for the transmissibility of these AIVs in a ferret model of human influenza virus transmission. In this current study we found that PB2 containing amino acids associated with transmissibility at 67, 152, 199, 508, and 649 and PB1 at 298, 642, and 667 were associated with more rapid viral replication kinetics, greater infectivity, more active polymerase complexes and greater kinetics of viral genome replication and transcription. Pathogenicity in the mouse model was also impacted, evident as greater weight loss and lung pathology associated with greater inflammatory lung cytokine expression. Further, these AIVs all contained the avian-type amino acids of PB2-E627, D701, G590, Q591 and T271. Therefore, our study provides novel insights into the role of the AIV polymerase complex in the zoonotic transmission of AIVs in mammals.
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Affiliation(s)
- Yaqin Bai
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Hui Lei
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Centre for Immunology & Infection, Hong Kong SAR, People's Republic of China
| | - Wenjun Song
- Guangzhou Laboratory, Guangzhou International Bio Island, Guangzhou, People’s Republic of China
| | | | - Jiaqi Wang
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Biying Xiao
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Zeynep A. Koçer
- Emerging Viral Diseases Laboratory, Izmir Biomedicine and Genome Center, Izmir, Türkiye
- Department of Biomedicine and Health Technologies, Izmir International Biomedicine and Genome Institute, Izmir, Türkiye
| | - Min-Suk Song
- Department of Microbiology, Chungbuk National University Medical School, Chungbuk, Korea
| | - Robert Webster
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Richard J. Webby
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Sook-San Wong
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Mark Zanin
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Centre for Immunology & Infection, Hong Kong SAR, People's Republic of China
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2
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Chesnokov A, Ivashchenko AA, Matsuzaki Y, Takashita E, Mishin VP, Ivachtchenko AV, Gubareva LV. Influenza C virus susceptibility to antivirals with different mechanisms of action. Antimicrob Agents Chemother 2024:e0172723. [PMID: 38587392 DOI: 10.1128/aac.01727-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/14/2024] [Indexed: 04/09/2024] Open
Abstract
Antiviral susceptibility of influenza viruses was assessed using a high-content imaging-based neutralization test. Cap-dependent endonuclease inhibitors, baloxavir and AV5116, were superior to AV5115 against type A viruses, and AV5116 was most effective against PA mutants tested. However, these three inhibitors displayed comparable activity (EC50 8-22 nM) against type C viruses from six lineages. Banana lectin and a monoclonal antibody, YA3, targeting the hemagglutinin-esterase protein effectively neutralized some, but not all, type C viruses.
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Affiliation(s)
- Anton Chesnokov
- Influenza Division, NCIRD, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
| | | | - Yoko Matsuzaki
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Emi Takashita
- Research Center for Influenza and Respiratory Viruses, National Institute of Infectious Diseases, Tokyo, Japan
| | - Vasiliy P Mishin
- Influenza Division, NCIRD, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
| | | | - Larisa V Gubareva
- Influenza Division, NCIRD, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
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3
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Quail MA, Corton C, Uphill J, Keane J, Gu Y. Identifying the best PCR enzyme for library amplification in NGS. Microb Genom 2024; 10. [PMID: 38578268 DOI: 10.1099/mgen.0.001228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024] Open
Abstract
Background. PCR amplification is a necessary step in many next-generation sequencing (NGS) library preparation methods [1, 2]. Whilst many PCR enzymes are developed to amplify single targets efficiently, accurately and with specificity, few are developed to meet the challenges imposed by NGS PCR, namely unbiased amplification of a wide range of different sizes and GC content. As a result PCR amplification during NGS library prep often results in bias toward GC neutral and smaller fragments. As NGS has matured, optimized NGS library prep kits and polymerase formulations have emerged and in this study we have tested a wide selection of available enzymes for both short-read Illumina library preparation and long fragment amplification ahead of long-read sequencing.We tested over 20 different hi-fidelity PCR enzymes/NGS amplification mixes on a range of Illumina library templates of varying GC content and composition, and find that both yield and genome coverage uniformity characteristics of the commercially available enzymes varied dramatically. Three enzymes Quantabio RepliQa Hifi Toughmix, Watchmaker Library Amplification Hot Start Master Mix (2X) 'Equinox' and Takara Ex Premier were found to give a consistent performance, over all genomes, that mirrored closely that observed for PCR-free datasets. We also test a range of enzymes for long-read sequencing by amplifying size fractionated S. cerevisiae DNA of average size 21.6 and 13.4 kb, respectively.The enzymes of choice for short-read (Illumina) library fragment amplification are Quantabio RepliQa Hifi Toughmix, Watchmaker Library Amplification Hot Start Master Mix (2X) 'Equinox' and Takara Ex Premier, with RepliQa also being the best performing enzyme from the enzymes tested for long fragment amplification prior to long-read sequencing.
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Affiliation(s)
| | - Craig Corton
- Wellcome Sanger Institute, Hinxton, Cambs., CB10 1SA, UK
| | - James Uphill
- Wellcome Sanger Institute, Hinxton, Cambs., CB10 1SA, UK
| | - Jacqueline Keane
- Department of Medicine, University of Cambridge, Cambridge, Cambs., CB2 1TN, UK
| | - Yong Gu
- Wellcome Sanger Institute, Hinxton, Cambs., CB10 1SA, UK
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4
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Ohta K, Saka N, Nishi Y, Nishio M. Nairovirus polymerase mutations associated with the establishment of persistent infection in human cells. J Virol 2024; 98:e0169823. [PMID: 38358288 PMCID: PMC10949423 DOI: 10.1128/jvi.01698-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/23/2024] [Indexed: 02/16/2024] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne virus of the Orthonairovirus genus, persistently infects tick cells. It has been reported to establish persistent infection in non-human primates, but virological analysis has not yet been performed in human cells. Here, we investigated whether and how nairoviruses persistently infect human cells using Hazara orthonairovirus (HAZV), a surrogate model for CCHFV. We established a human cell line that was persistently infected with HAZV. Surprisingly, virions of persistently infected HAZV (HAZVpi) were not observed in the culture supernatants. There were five mutations (mut1, mut2, mut3, mut4, and mut5) in L protein of HAZVpi. Mutations in L protein of HAZVpi contribute to non-detection of virion in the supernatants. Lmut4 was found to cause low viral growth rate, despite its high polymerase activity. The low growth rate was restored by Lmut2, Lmut3, and Lmut5. The polymerase activity of Lmut1 was extremely low, and recombinant HAZV carrying Lmut1 (rHAZV/Lmut1) was not released into the supernatants. However, genomes of rHAZV/Lmut1 were retained in the infected cells. All mutations (Lmut1-5) found in L protein of HAZVpi were required for experimental reproduction of HAZVpi, and only Lmut1 and Lmut4 were insufficient. We demonstrated that point mutations in viral polymerase contribute to the establishment of persistent HAZV infection. Furthermore, innate immunity was found to be suppressed in HAZVpi-infected cells, which also potentially contributes to viral persistence. This is the first presentation of a possible mechanism behind how nairoviruses establish persistent infection in human cells. IMPORTANCE We investigated whether and how nairoviruses persistently infect human cells, using Hazara orthonairovirus (HAZV), a surrogate model for Crimean-Congo hemorrhagic fever virus. We established a human cell line that was persistently infected with HAZV. Five mutations were found in L protein of persistently infected HAZV (HAZVpi): mut1, mut2, mut3, mut4, and mut5. Among them, Lmut1 and Lmut4 restricted viral growth by low polymerase activity and low growth rate, respectively, leading to inhibition of viral overgrowth. The restriction of viral growth caused by Lmut1 and Lmut4 was compensated by other mutations, including Lmut2, Lmut3, and Lmut5. Each of the mutations found in L protein of HAZVpi was concluded to cooperatively modulate viral growth, which facilitates the establishment of persistent infection. Suppression of innate immunity also potentially contributes to virus persistence. This is the first presentation of a possible mechanism behind how nairoviruses establish persistent infection in human cells.
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Affiliation(s)
- Keisuke Ohta
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Naoki Saka
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Yuzuha Nishi
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
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Guo L, Bao Y, Zhao Y, Ren Z, Bi L, Zhang X, Liu C, Hou X, Wang MD, Sun B. Joint Efforts of Replicative Helicase and SSB Ensure Inherent Replicative Tolerance of G-Quadruplex. Adv Sci (Weinh) 2024; 11:e2307696. [PMID: 38126671 PMCID: PMC10916570 DOI: 10.1002/advs.202307696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/28/2023] [Indexed: 12/23/2023]
Abstract
G-quadruplex (G4) is a four-stranded noncanonical DNA structure that has long been recognized as a potential hindrance to DNA replication. However, how replisomes effectively deal with G4s to avoid replication failure is still obscure. Here, using single-molecule and ensemble approaches, the consequence of the collision between bacteriophage T7 replisome and an intramolecular G4 located on either the leading or lagging strand is examined. It is found that the adjacent fork junctions induced by G4 formation incur the binding of T7 DNA polymerase (DNAP). In addition to G4, these inactive DNAPs present insuperable obstacles, impeding the progression of DNA synthesis. Nevertheless, T7 helicase can dismantle them and resolve lagging-strand G4s, paving the way for the advancement of the replication fork. Moreover, with the assistance of the single-stranded DNA binding protein (SSB) gp2.5, T7 helicase is also capable of maintaining a leading-strand G4 structure in an unfolded state, allowing for a fraction of T7 DNAPs to synthesize through without collapse. These findings broaden the functional repertoire of a replicative helicase and underscore the inherent G4 tolerance of a replisome.
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Affiliation(s)
- Lijuan Guo
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Yanling Bao
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Yilin Zhao
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Zhiyun Ren
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesShanghai200031China
- University of Chinese Academy of SciencesBeijing100049China
| | - Lulu Bi
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Xia Zhang
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Cong Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai201210China
| | - Xi‐Miao Hou
- College of Life SciencesNorthwest A&F UniversityYanglingShaanxi712100China
| | - Michelle D. Wang
- Department of Physics, Laboratory of Atomic and Solid State PhysicsCornell UniversityIthacaNY14853USA
- Howard Hughes Medical InstituteCornell UniversityIthacaNY14853USA
| | - Bo Sun
- School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China
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6
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McRae EKS, Wan CJK, Kristoffersen EL, Hansen K, Gianni E, Gallego I, Curran JF, Attwater J, Holliger P, Andersen ES. Cryo-EM structure and functional landscape of an RNA polymerase ribozyme. Proc Natl Acad Sci U S A 2024; 121:e2313332121. [PMID: 38207080 PMCID: PMC10801858 DOI: 10.1073/pnas.2313332121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
The emergence of an RNA replicase capable of self-replication is considered an important stage in the origin of life. RNA polymerase ribozymes (PR) - including a variant that uses trinucleotide triphosphates (triplets) as substrates - have been created by in vitro evolution and are the closest functional analogues of the replicase, but the structural basis for their function is poorly understood. Here we use single-particle cryogenic electron microscopy (cryo-EM) and high-throughput mutation analysis to obtain the structure of a triplet polymerase ribozyme (TPR) apoenzyme and map its functional landscape. The cryo-EM structure at 5-Å resolution reveals the TPR as an RNA heterodimer comprising a catalytic subunit and a noncatalytic, auxiliary subunit, resembling the shape of a left hand with thumb and fingers at a 70° angle. The two subunits are connected by two distinct kissing-loop (KL) interactions that are essential for polymerase function. Our combined structural and functional data suggest a model for templated RNA synthesis by the TPR holoenzyme, whereby heterodimer formation and KL interactions preorganize the TPR for optimal primer-template duplex binding, triplet substrate discrimination, and templated RNA synthesis. These results provide a better understanding of TPR structure and function and should aid the engineering of more efficient PRs.
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Affiliation(s)
- Ewan K. S. McRae
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Christopher J. K. Wan
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Emil L. Kristoffersen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Kalinka Hansen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
| | - Edoardo Gianni
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Isaac Gallego
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Joseph F. Curran
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - James Attwater
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Philipp Holliger
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Ebbe S. Andersen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
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Wollman AJM, Syeda AH, Howard JAL, Payne-Dwyer A, Leech A, Warecka D, Guy C, McGlynn P, Hawkins M, Leake MC. Tetrameric UvrD Helicase Is Located at the E. Coli Replisome due to Frequent Replication Blocks. J Mol Biol 2024; 436:168369. [PMID: 37977299 DOI: 10.1016/j.jmb.2023.168369] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/19/2023]
Abstract
DNA replication in all organisms must overcome nucleoprotein blocks to complete genome duplication. Accessory replicative helicases in Escherichia coli, Rep and UvrD, help remove these blocks and aid the re-initiation of replication. Mechanistic details of Rep function have emerged from recent live cell studies; however, the division of UvrD functions between its activities in DNA repair and role as an accessory helicase remain unclear in live cells. By integrating super-resolved single-molecule fluorescence microscopy with biochemical analysis, we find that UvrD self-associates into tetrameric assemblies and, unlike Rep, is not recruited to a specific replisome protein despite being found at approximately 80% of replication forks. Instead, its colocation with forks is likely due to the very high frequency of replication blocks composed of DNA-bound proteins, including RNA polymerase and factors involved in repairing DNA damage. Deleting rep and DNA repair factor genes mutS and uvrA, and inhibiting transcription through RNA polymerase mutation and antibiotic inhibition, indicates that the level of UvrD at the fork is dependent on UvrD's function. Our findings show that UvrD is recruited to sites of nucleoprotein blocks via different mechanisms to Rep and plays a multi-faceted role in ensuring successful DNA replication.
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Affiliation(s)
- Adam J M Wollman
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Aisha H Syeda
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Jamieson A L Howard
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alex Payne-Dwyer
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Andrew Leech
- Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Dominika Warecka
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Colin Guy
- Covance Laboratories Ltd., Otley Road, Harrogate HG3 1PY, United Kingdom
| | - Peter McGlynn
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Michelle Hawkins
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom.
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8
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Hohensee L, Scheibner D, Schäfer A, Shelton H, Mettenleiter TC, Breithaupt A, Dorhoi A, Abdelwhab EM, Blohm U. The role of PB1-F2 in adaptation of high pathogenicity avian influenza virus H7N7 in chickens. Vet Res 2024; 55:5. [PMID: 38173025 PMCID: PMC10765749 DOI: 10.1186/s13567-023-01257-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024] Open
Abstract
Avian influenza viruses (AIV) of the H7N7 subtype are enzootic in the wild bird reservoir in Europe, cause infections in poultry, and have sporadically infected humans. The non-structural protein PB1-F2 is encoded in a second open frame in the polymerase segment PB1 and its sequence varies with the host of origin. While mammalian isolates predominantly carry truncated forms, avian isolates typically express full-length PB1-F2. PB1-F2 is a virulence factor of influenza viruses in mammals. It modulates the host immune response, causing immunopathology and increases pro-inflammatory responses. The role of full-length PB1-F2 in IAV pathogenesis as well as its impact on virus adaptation and virulence in poultry remains enigmatic. Here, we characterised recombinant high pathogenicity AIV (HPAIV) H7N7 expressing or lacking PB1-F2 in vitro and in vivo in chickens. In vitro, full-length PB1-F2 modulated viability of infected chicken fibroblasts by limiting apoptosis. In chickens, PB1-F2 promoted gastrointestinal tropism, as demonstrated by enhanced viral replication in the gut and increased cloacal shedding. PB1-F2's effects on cellular immunity however were marginal. Overall, chickens infected with full-length PB1-F2 virus survived for shorter periods, indicating that PB1-F2 is also a virulence factor in bird-adapted viruses.
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Affiliation(s)
- Luise Hohensee
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
- Infection Pathogenesis, TUM School of Life Sciences, Technische Universität München, 85354, Freising, Germany
| | - David Scheibner
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Alexander Schäfer
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Holly Shelton
- The Pirbright Institute, Pirbright, Ash Road, Surrey, GU24 0NF, UK
| | - Thomas C Mettenleiter
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Angele Breithaupt
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Anca Dorhoi
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Elsayed M Abdelwhab
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Ulrike Blohm
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald, Insel Riems, Germany.
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9
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Chuchaona W, Vongpunsawad S, Lawtongkum W, Thepnarong N, Poovorawan Y. Acute Gastroenteritis Associated with Norovirus GII.8[P8], Thailand, 2023. Emerg Infect Dis 2024; 30:194-197. [PMID: 38147526 PMCID: PMC10756372 DOI: 10.3201/eid3001.231264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023] Open
Abstract
Acute gastroenteritis associated with human norovirus infection was reported in Phuket, Thailand, in June 2023. We amplified GII.8[P8] from the outbreak stool specimens. Retrospective sample analysis identified infrequent GII.8[P8] in the country beginning in 2018. In all, the 10 whole-genome GII.8[P8] sequences from Thailand we examined had no evidence of genotypic recombination.
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10
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Carminati M, Rodríguez-Molina JB, Manav MC, Bellini D, Passmore LA. A direct interaction between CPF and RNA Pol II links RNA 3' end processing to transcription. Mol Cell 2023; 83:4461-4478.e13. [PMID: 38029752 PMCID: PMC10783616 DOI: 10.1016/j.molcel.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/25/2023] [Accepted: 11/06/2023] [Indexed: 12/01/2023]
Abstract
Transcription termination by RNA polymerase II (RNA Pol II) is linked to RNA 3' end processing by the cleavage and polyadenylation factor (CPF or CPSF). CPF contains endonuclease, poly(A) polymerase, and protein phosphatase activities, which cleave and polyadenylate pre-mRNAs and dephosphorylate RNA Pol II to control transcription. Exactly how the RNA 3' end processing machinery is coupled to transcription remains unclear. Here, we combine in vitro reconstitution, structural studies, and genome-wide analyses to show that yeast CPF physically and functionally interacts with RNA Pol II. Surprisingly, CPF-mediated dephosphorylation promotes the formation of an RNA Pol II stalk-to-stalk homodimer in vitro. This dimer is compatible with transcription but not with the binding of transcription elongation factors. Disruption of the dimerization interface in cells causes transcription defects, including altered RNA Pol II abundance on protein-coding genes, tRNA genes, and intergenic regions. We hypothesize that RNA Pol II dimerization may provide a mechanistic basis for the allosteric model of transcription termination.
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Affiliation(s)
| | | | - M Cemre Manav
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Dom Bellini
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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11
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Li Y, Arcos S, Sabsay KR, te Velthuis AJW, Lauring AS. Deep mutational scanning reveals the functional constraints and evolutionary potential of the influenza A virus PB1 protein. J Virol 2023; 97:e0132923. [PMID: 37882522 PMCID: PMC10688322 DOI: 10.1128/jvi.01329-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/08/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The influenza virus polymerase is important for adaptation to new hosts and, as a determinant of mutation rate, for the process of adaptation itself. We performed a deep mutational scan of the polymerase basic 1 (PB1) protein to gain insights into the structural and functional constraints on the influenza RNA-dependent RNA polymerase. We find that PB1 is highly constrained at specific sites that are only moderately predicted by the global structure or larger domain. We identified a number of beneficial mutations, many of which have been shown to be functionally important or observed in influenza virus' natural evolution. Overall, our atlas of PB1 mutations and their fitness impacts serves as an important resource for future studies of influenza replication and evolution.
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Affiliation(s)
- Yuan Li
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Sarah Arcos
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Kimberly R. Sabsay
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute, Princeton University, Princeton, New Jersey, USA
| | | | - Adam S. Lauring
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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12
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Comunale BA, Larson RJ, Jackson-Ward E, Singh A, Koback FL, Engineer LD. The Functional Implications of Broad Spectrum Bioactive Compounds Targeting RNA-Dependent RNA Polymerase (RdRp) in the Context of the COVID-19 Pandemic. Viruses 2023; 15:2316. [PMID: 38140557 PMCID: PMC10747147 DOI: 10.3390/v15122316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND As long as COVID-19 endures, viral surface proteins will keep changing and new viral strains will emerge, rendering prior vaccines and treatments decreasingly effective. To provide durable targets for preventive and therapeutic agents, there is increasing interest in slowly mutating viral proteins, including non-surface proteins like RdRp. METHODS A scoping review of studies was conducted describing RdRp in the context of COVID-19 through MEDLINE/PubMed and EMBASE. An iterative approach was used with input from content experts and three independent reviewers, focused on studies related to either RdRp activity inhibition or RdRp mechanisms against SARS-CoV-2. RESULTS Of the 205 records screened, 43 studies were included in the review. Twenty-five evaluated RdRp activity inhibition, and eighteen described RdRp mechanisms of existing drugs or compounds against SARS-CoV-2. In silico experiments suggested that RdRp inhibitors developed for other RNA viruses may be effective in disrupting SARS-CoV-2 replication, indicating a possible reduction of disease progression from current and future variants. In vitro, in vivo, and human clinical trial studies were largely consistent with these findings. CONCLUSIONS Future risk mitigation and treatment strategies against forthcoming SARS-CoV-2 variants should consider targeting RdRp proteins instead of surface proteins.
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Affiliation(s)
- Brittany A. Comunale
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Robin J. Larson
- Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
- Department of Palliative Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Erin Jackson-Ward
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Aditi Singh
- Department of Biological Sciences, University of California San Diego, La Jolla, CA 92161, USA
| | | | - Lilly D. Engineer
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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13
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Anderson ML, Sullivan OM, Nichols SL, Kaylor L, Kelly DF, McDonald Esstman S. Rotavirus core shell protein sites that regulate intra-particle polymerase activity. J Virol 2023; 97:e0086023. [PMID: 37830817 PMCID: PMC10617381 DOI: 10.1128/jvi.00860-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/06/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Rotaviruses are important causes of severe gastroenteritis in young children. A characteristic feature of rotaviruses is that they copy ribonucleic acid (RNA) inside of the viral particle. In fact, the viral polymerase (VP1) only functions when it is connected to the viral inner core shell protein (VP2). Here, we employed a biochemical assay to identify which sites of VP2 are critical for regulating VP1 activity. Specifically, we engineered VP2 proteins to contain amino acid changes at structurally defined sites and assayed them for their capacity to support VP1 function in a test tube. Through this work, we were able to identify several VP2 residues that appeared to regulate the activity of the polymerase, positively and negatively. These results are important because they help explain how rotavirus synthesizes its RNA while inside of particles and they identify targets for the future rational design of drugs to prevent rotavirus disease.
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Affiliation(s)
| | - Owen M. Sullivan
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Sarah L. Nichols
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Liam Kaylor
- Department of Biomedical Engineering, State University, University Park, Pennsylvania, USA
| | - Deborah F. Kelly
- Department of Biomedical Engineering, State University, University Park, Pennsylvania, USA
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14
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Qin T, Hu B, Zhao Q, Wang Y, Wang S, Luo D, Lyu J, Chen Y, Gan J, Huang Z. Structural Insight into Polymerase Mechanism via a Chiral Center Generated with a Single Selenium Atom. Int J Mol Sci 2023; 24:15758. [PMID: 37958741 PMCID: PMC10647396 DOI: 10.3390/ijms242115758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/19/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
DNA synthesis catalyzed by DNA polymerase is essential for all life forms, and phosphodiester bond formation with phosphorus center inversion is a key step in this process. Herein, by using a single-selenium-atom-modified dNTP probe, we report a novel strategy to visualize the reaction stereochemistry and catalysis. We capture the before- and after-reaction states and provide explicit evidence of the center inversion and in-line attacking SN2 mechanism of DNA polymerization, while solving the diastereomer absolute configurations. Further, our kinetic and thermodynamic studies demonstrate that in the presence of Mg2+ ions (or Mn2+), the binding affinity (Km) and reaction selectivity (kcat/Km) of dGTPαSe-Rp were 51.1-fold (or 19.5-fold) stronger and 21.8-fold (or 11.3-fold) higher than those of dGTPαSe-Sp, respectively, indicating that the diastereomeric Se-Sp atom was quite disruptive of the binding and catalysis. Our findings reveal that the third metal ion is much more critical than the other two metal ions in both substrate recognition and bond formation, providing insights into how to better design the polymerase inhibitors and discover the therapeutics.
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Affiliation(s)
- Tong Qin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
| | - Bei Hu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
| | - Qianwei Zhao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
- Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450000, China
| | - Yali Wang
- College of Bioengineering, Sichuan University of Science and Engineering, Yibin 644000, China;
| | - Shaoxin Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
| | - Danyan Luo
- SeNA Research Institute and Szostak-CDHT Large Nucleic Acid Institute, Chengdu 618000, China;
| | - Jiazhen Lyu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
| | - Yiqing Chen
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China;
| | - Jianhua Gan
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China;
| | - Zhen Huang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China; (T.Q.); (B.H.); (Q.Z.); (S.W.); (J.L.)
- SeNA Research Institute and Szostak-CDHT Large Nucleic Acid Institute, Chengdu 618000, China;
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 610000, China
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15
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Andreev K, Jones JC, Seiler P, Kandeil A, Turner JCM, Barman S, Rubrum AM, Webby RJ, Govorkova EA. Antiviral Susceptibility of Highly Pathogenic Avian Influenza A(H5N1) Viruses Circulating Globally in 2022-2023. J Infect Dis 2023:jiad418. [PMID: 37770028 DOI: 10.1093/infdis/jiad418] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/14/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023] Open
Abstract
The antiviral susceptibility of currently circulating (2022-2023) highly pathogenic avian influenza (HPAI) A(H5N1) viruses was assessed by genotypic and phenotypic approaches. The frequency of neuraminidase (NA) and polymerase acidic (PA) substitutions associated with reduced inhibition by NA inhibitors (NAIs) (21/2698, 0.78%) or by the PA inhibitor baloxavir (14/2600, 0.54%) was low. Phenotypic testing of 22 clade 2.3.2.1a and 2.3.4.4b viruses revealed broad susceptibility to NAIs and baloxavir concluding that most contemporary HPAI A(H5N1) viruses retain susceptibility to antiviral drugs. Novel NA-K432E and NA-T438I substitutions (N2 numbering) were identified at elevated frequencies (104/2698, 3.85%) and caused reduced zanamivir and peramivir inhibition.
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Affiliation(s)
- Konstantin Andreev
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Jeremy C Jones
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Patrick Seiler
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Ahmed Kandeil
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Jasmine C M Turner
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Subrata Barman
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Adam M Rubrum
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Richard J Webby
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
| | - Elena A Govorkova
- Department of Infectious Diseases, St. Jude Children's Research Hospital; Memphis, TN, USA
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16
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Alguridi HI, Alzahrani F, Almalki S, Zamzami MA, Altayb HN. Identification and molecular docking of novel chikungunya virus NSP4 inhibitory peptides from camel milk proteins. J Biomol Struct Dyn 2023:1-16. [PMID: 37668009 DOI: 10.1080/07391102.2023.2254398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 08/28/2023] [Indexed: 09/06/2023]
Abstract
The chikungunya (CHIK) virus is an arbovirus belonging to the alphavirus (Togaviridae family). Around 85% of infected individuals suffer from symptoms such as high fever and severe joint pain; about 30 to 40% will develop a chronic joint illness. The Nsp4 protease is the most conserved protein in the alphavirus family and serves as an RNA-dependent RNA polymerase (RdRp). Targeting this enzyme might inhibit the CHIKV replication cycle. This work aims to in silico study the CHIKV RdRp inhibitory effect of peptides derived from camel milk protein as antiviral peptides. Various bioinformatics tools were recruited to identify, screen, predict and assess peptides obtained from camel milk as antiviral peptides (AVPs). During this study, CHIKV Nsp4 (polymerase) was used as a target to be inhibited by interaction with peptides derived from camel milk protein. Among 91 putative bioactive peptides, the best predicted 5 were further evaluated. Molecular docking showed that the top 5 AVPs generated better docking scores and interacted well with active sites of Nsp4 by the formation of different hydrogen bonds as well as other bonds. AVP63 and AVP20 showed the best Molecular docking and MD simulation results. The residue 315ASP of the GDD motif (catalytic core) exhibited a favorable interaction with the AVPs. The findings of this study suggest that the AVP20 derived from camel milk protein can be a potential novel CHIKV polymerase inhibitor.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Hassan I Alguridi
- Molecular Biology Department, Jeddah Regional Laboratory, Ministry of Health, Jeddah, Saudi Arabia
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University Jeddah, Saudi Arabia
- Research Unit, Jeddah Regional Laboratory, Ministry of Health, Jeddah, Saudi Arabia
| | - Faisal Alzahrani
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University Jeddah, Saudi Arabia
- Centre for Artificial Intelligence in Precision Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- King Fahd Medical Research Center, Embryonic Stem Cells Unit, King Abdulaziz University Jeddah, Saudi Arabia
| | - Safar Almalki
- Molecular Biology Department, Jeddah Regional Laboratory, Ministry of Health, Jeddah, Saudi Arabia
- Laboratories and Blood Banks Administration, Ministry of Health, Jeddah, Saudi Arabia
| | - Mazin A Zamzami
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University Jeddah, Saudi Arabia
- Centre for Artificial Intelligence in Precision Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hisham N Altayb
- Department of Biochemistry, Faculty of Sciences, King Abdulaziz University Jeddah, Saudi Arabia
- Centre for Artificial Intelligence in Precision Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
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17
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Herbert A. Flipons and small RNAs accentuate the asymmetries of pervasive transcription by the reset and sequence-specific microcoding of promoter conformation. J Biol Chem 2023; 299:105140. [PMID: 37544644 PMCID: PMC10474125 DOI: 10.1016/j.jbc.2023.105140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
The role of alternate DNA conformations such as Z-DNA in the regulation of transcription is currently underappreciated. These structures are encoded by sequences called flipons, many of which are enriched in promoter and enhancer regions. Through a change in their conformation, flipons provide a tunable mechanism to mechanically reset promoters for the next round of transcription. They act as actuators that capture and release energy to ensure that the turnover of the proteins at promoters is optimized to cell state. Likewise, the single-stranded DNA formed as flipons cycle facilitates the docking of RNAs that are able to microcode promoter conformations and canalize the pervasive transcription commonly observed in metazoan genomes. The strand-specific nature of the interaction between RNA and DNA likely accounts for the known asymmetry of epigenetic marks present on the histone tetramers that pair to form nucleosomes. The role of these supercoil-dependent processes in promoter choice and transcriptional interference is reviewed. The evolutionary implications are examined: the resilience and canalization of flipon-dependent gene regulation is contrasted with the rapid adaptation enabled by the spread of flipon repeats throughout the genome. Overall, the current findings underscore the important role of flipons in modulating the readout of genetic information and how little we know about their biology.
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Affiliation(s)
- Alan Herbert
- Discovery Division, InsideOutBio, Charlestown, Massachusetts, USA.
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18
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Alves-Lopes R, Lacchini S, Neves KB, Harvey A, Montezano AC, Touyz RM. Vasoprotective effects of NOX4 are mediated via polymerase and transient receptor potential melastatin 2 cation channels in endothelial cells. J Hypertens 2023; 41:1389-1400. [PMID: 37272080 PMCID: PMC10399938 DOI: 10.1097/hjh.0000000000003478] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/06/2023]
Abstract
BACKGROUND NOX4 activation has been implicated to have vasoprotective and blood pressure (BP)-lowering effects. Molecular mechanisms underlying this are unclear, but NOX4-induced regulation of the redox-sensitive Ca 2+ channel TRPM2 and effects on endothelial nitric oxide synthase (eNOS)-nitric oxide signalling may be important. METHOD Wild-type and LinA3, renin-expressing hypertensive mice, were crossed with NOX4 knockout mice. Vascular function was measured by myography. Generation of superoxide (O 2- ) and hydrogen peroxide (H 2 O 2 ) were assessed by lucigenin and amplex red, respectively, and Ca 2+ influx by Cal-520 fluorescence in rat aortic endothelial cells (RAEC). RESULTS BP was increased in NOX4KO, LinA3 and LinA3/NOX4KO mice. This was associated with endothelial dysfunction and vascular remodelling, with exaggerated effects in NOX4KO groups. The TRPM2 activator, ADPR, improved vascular relaxation in LinA3/NOX4KO mice, an effect recapitulated by H 2 O 2 . Inhibition of PARP and TRPM2 with olaparib and 2-APB, respectively, recapitulated endothelial dysfunction in NOX4KO. In endothelial cells, Ang II increased H 2 O 2 generation and Ca 2+ influx, effects reduced by TRPM2 siRNA, TRPM2 inhibitors (8-br-cADPR, 2-APB), olaparib and GKT137831 (NOX4 inhibitor). Ang II-induced eNOS activation was blocked by NOX4 and TRPM2 siRNA, GKT137831, PEG-catalase and 8-br-cADPR. CONCLUSION Our findings indicate that NOX4-induced H 2 O 2 production activates PARP/TRPM2, Ca 2+ influx, eNOS activation and nitric oxide release in endothelial cells. NOX4 deficiency impairs Ca 2+ homeostasis leading to endothelial dysfunction, an effect exacerbated in hypertension. We define a novel pathway linking endothelial NOX4/H 2 O 2 to eNOS/nitric oxide through PARP/TRPM2/Ca 2+ . This vasoprotective pathway is perturbed when NOX4 is downregulated and may have significance in conditions associated with endothelial dysfunction, including hypertension.
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Affiliation(s)
- Rheure Alves-Lopes
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Silvia Lacchini
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Karla B. Neves
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, UK
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Adam Harvey
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Augusto C. Montezano
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
| | - Rhian M. Touyz
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
- School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
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19
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Gidi Y, Robert A, Tordo A, Lovell TC, Ramos-Sanchez J, Sakaya A, Götte M, Cosa G. Binding and Sliding Dynamics of the Hepatitis C Virus Polymerase: Hunting the 3' Terminus. ACS Infect Dis 2023; 9:1488-1498. [PMID: 37436367 DOI: 10.1021/acsinfecdis.3c00048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
The hepatitis C virus (HCV) nonstructural protein 5B (NS5B) polymerase catalyzes the replication of the (+) single-stranded RNA genome of HCV. In vitro studies have shown that replication can be performed in the absence of a primer. However, the dynamics and mechanism by which NS5B locates the 3'-terminus of the RNA template to initiate de novo synthesis remain elusive. Here, we performed single-molecule fluorescence studies based on protein-induced fluorescence enhancement reporting on NS5B dynamics on a short model RNA substrate. Our results suggest that NS5B exists in a fully open conformation in solution wherefrom it accesses its binding site along RNA and then closes. Our results revealed two NS5B binding modes: an unstable one resulting in rapid dissociation, and a stable one characterized by a larger residence time on the substrate. We associate these bindings to an unproductive and productive orientation, respectively. Addition of extra mono (Na+)- and divalent (Mg2+) ions increases the mobility of NS5B along its RNA substrate. However, only Mg2+ ions induce a decrease in NS5B residence time. Dwell times of residence increase with the length of the single-stranded template, suggesting that NS5B unbinds its substrate by unthreading the template rather than by spontaneous opening.
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Affiliation(s)
- Yasser Gidi
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Anaïs Robert
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Alix Tordo
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Terri C Lovell
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Jorge Ramos-Sanchez
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Aya Sakaya
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
| | - Matthias Götte
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Gonzalo Cosa
- Department of Chemistry and Quebec Center for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada
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20
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Abstract
Formation of the 3' end of a eukaryotic mRNA is a key step in the production of a mature transcript. This process is mediated by a number of protein factors that cleave the pre-mRNA, add a poly(A) tail, and regulate transcription by protein dephosphorylation. Cleavage and polyadenylation specificity factor (CPSF) in humans, or cleavage and polyadenylation factor (CPF) in yeast, coordinates these enzymatic activities with each other, with RNA recognition, and with transcription. The site of pre-mRNA cleavage can strongly influence the translation, stability, and localization of the mRNA. Hence, cleavage site selection is highly regulated. The length of the poly(A) tail is also controlled to ensure that every transcript has a similar tail when it is exported from the nucleus. In this review, we summarize new mechanistic insights into mRNA 3'-end processing obtained through structural studies and biochemical reconstitution and outline outstanding questions in the field.
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Affiliation(s)
- Vytautė Boreikaitė
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom;
| | - Lori A Passmore
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom;
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21
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Weckener M, Woodward LS, Clarke BR, Liu H, Ward PN, Le Bas A, Bhella D, Whitfield C, Naismith JH. The lipid linked oligosaccharide polymerase Wzy and its regulating co-polymerase, Wzz, from enterobacterial common antigen biosynthesis form a complex. Open Biol 2023; 13:220373. [PMID: 36944376 PMCID: PMC10030265 DOI: 10.1098/rsob.220373] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
The enterobacterial common antigen (ECA) is a carbohydrate polymer that is associated with the cell envelope in the Enterobacteriaceae. ECA contains a repeating trisaccharide which is polymerized by WzyE, a member of the Wzy membrane protein polymerase superfamily. WzyE activity is regulated by a membrane protein polysaccharide co-polymerase, WzzE. Förster resonance energy transfer experiments demonstrate that WzyE and WzzE from Pectobacterium atrosepticum form a complex in vivo, and immunoblotting and cryo-electron microscopy (cryo-EM) analysis confirm a defined stoichiometry of approximately eight WzzE to one WzyE. Low-resolution cryo-EM reconstructions of the complex, aided by an antibody recognizing the C-terminus of WzyE, reveals WzyE sits in the central membrane lumen formed by the octameric arrangement of the transmembrane helices of WzzE. The pairing of Wzy and Wzz is found in polymerization systems for other bacterial polymers, including lipopolysaccharide O-antigens and capsular polysaccharides. The data provide new structural insight into a conserved mechanism for regulating polysaccharide chain length in bacteria.
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Affiliation(s)
- Miriam Weckener
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Laura S. Woodward
- Centre Biomedical Sciences, North Haugh, University of St Andrews, St Andrews KY16 9ST, UK
| | - Bradley R. Clarke
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - Huanting Liu
- Centre Biomedical Sciences, North Haugh, University of St Andrews, St Andrews KY16 9ST, UK
| | - Philip N. Ward
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Audrey Le Bas
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - David Bhella
- MRC—University of Glasgow Centre for Virus Research, University of Glasgow, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1Q, UK
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - James H. Naismith
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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22
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Sutto-Ortiz P, Eléouët JF, Ferron F, Decroly E. Biochemistry of the Respiratory Syncytial Virus L Protein Embedding RNA Polymerase and Capping Activities. Viruses 2023; 15:v15020341. [PMID: 36851554 PMCID: PMC9960070 DOI: 10.3390/v15020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/12/2023] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
The human respiratory syncytial virus (RSV) is a negative-sense, single-stranded RNA virus. It is the major cause of severe acute lower respiratory tract infection in infants, the elderly population, and immunocompromised individuals. There is still no approved vaccine or antiviral treatment against RSV disease, but new monoclonal prophylactic antibodies are yet to be commercialized, and clinical trials are in progress. Hence, urgent efforts are needed to develop efficient therapeutic treatments. RSV RNA synthesis comprises viral transcription and replication that are catalyzed by the large protein (L) in coordination with the phosphoprotein polymerase cofactor (P), the nucleoprotein (N), and the M2-1 transcription factor. The replication/transcription is orchestrated by the L protein, which contains three conserved enzymatic domains: the RNA-dependent RNA polymerase (RdRp), the polyribonucleotidyl transferase (PRNTase or capping), and the methyltransferase (MTase) domain. These activities are essential for the RSV replicative cycle and are thus considered as attractive targets for the development of therapeutic agents. In this review, we summarize recent findings about RSV L domains structure that highlight how the enzymatic activities of RSV L domains are interconnected, discuss the most relevant and recent antivirals developments that target the replication/transcription complex, and conclude with a perspective on identified knowledge gaps that enable new research directions.
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Affiliation(s)
| | - Jean-François Eléouët
- Unité de Virologie et Immunologie Moléculaires, INRAE, Université Paris Saclay, F78350 Jouy en Josas, France
| | - François Ferron
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- European Virus Bioinformatics Center, Leutragraben 1, 07743 Jena, Germany
| | - Etienne Decroly
- Aix Marseille Université, CNRS, AFMB, UMR, 7257 Marseille, France
- Correspondence:
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23
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Wang YR, Dai YC, Liu HG, Vlasák J, Buchanan P, Yuan Y, Wu YD. A new contribution to Megasporoporia sensu lato: Six new species and three new combinations. Front Microbiol 2022; 13:1046777. [PMID: 36569086 PMCID: PMC9777752 DOI: 10.3389/fmicb.2022.1046777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022] Open
Abstract
Megasporoporia sensu lato has recently been intensively studied in China and South America, and four independent clades representing four genera have been recognized phylogenetically. In this study, more samples, mostly from subtropical and tropical Asia, Oceania, and East Africa, are analyzed. A phylogeny based on a 4-gene dataset of sequences (ITS + nLSU + mtSSU + tef) has confirmed the presence of four genera in Megasporoporia sensu lato: Jorgewrightia, Mariorajchenbergia, Megasporia, and Megasporoporia sensu stricto. Six new species, Jorgewrightia austroasiana, Jorgewrightia irregularis, Jorgewrightia tenuis, Mariorajchenbergia subleucoplaca, Megasporia olivacea, and Megasporia sinuosa, are described based on morphology and phylogenetic analysis. Three new combinations are proposed, viz. Jorgewrightia kirkii, Mariorajchenbergia epitephra, and Mariorajchenbergia leucoplaca. To date, 36 species of Megasporoporia sensu lato are accepted and an identification key to these species is provided. In addition, the identification of Dichomitus amazonicus, Dichomitus cylindrosporus, and Megasporoporia hexagonoides is discussed.
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Affiliation(s)
- Ya-Rong Wang
- Institute of Microbiology, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yu-Cheng Dai
- Institute of Microbiology, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Hong-Gao Liu
- School of Agronomy and Life Sciences, Zhaotong University, Zhaotong, China
| | - Josef Vlasák
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Ceské Budějovice, Czechia
| | - Peter Buchanan
- Manaaki Whenua - Landcare Research, Auckland, New Zealand
| | - Yuan Yuan
- Institute of Microbiology, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China,*Correspondence: Yuan Yuan
| | - Ying-Da Wu
- Institute of Microbiology, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China,Key Laboratory of Forest and Grassland Fire Risk Prevention, Ministry of Emergency Management, China Fire and Rescue Institute, Beijing, China,Ying-Da Wu
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24
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Ramos PRPDS, Mottin M, Lima CS, Assis LR, de Oliveira KZ, Mesquita NCMR, Cassani NM, Santos IA, Borba JVVB, Fiaia Costa VA, Neves BJ, Guido RVC, Oliva G, Jardim ACG, Regasini LO, Andrade CH. Natural Compounds as Non-Nucleoside Inhibitors of Zika Virus Polymerase through Integration of In Silico and In Vitro Approaches. Pharmaceuticals (Basel) 2022; 15. [PMID: 36558945 DOI: 10.3390/ph15121493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Although the past epidemic of Zika virus (ZIKV) resulted in severe neurological consequences for infected infants and adults, there are still no approved drugs to treat ZIKV infection. In this study, we applied computational approaches to screen an in-house database of 77 natural and semi-synthetic compounds against ZIKV NS5 RNA-dependent RNA-polymerase (NS5 RdRp), an essential protein for viral RNA elongation during the replication process. For this purpose, we integrated computational approaches such as binding-site conservation, chemical space analysis and molecular docking. As a result, we prioritized nine virtual hits for experimental evaluation. Enzymatic assays confirmed that pedalitin and quercetin inhibited ZIKV NS5 RdRp with IC50 values of 4.1 and 0.5 µM, respectively. Moreover, pedalitin also displayed antiviral activity on ZIKV infection with an EC50 of 19.28 µM cell-based assays, with low toxicity in Vero cells (CC50 = 83.66 µM) and selectivity index of 4.34. These results demonstrate the potential of the natural compounds pedalitin and quercetin as candidates for structural optimization studies towards the discovery of new anti-ZIKV drug candidates.
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25
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Pourseif MM, Masoudi-Sobhanzadeh Y, Azari E, Parvizpour S, Barar J, Ansari R, Omidi Y. Self-amplifying mRNA vaccines: Mode of action, design, development and optimization. Drug Discov Today 2022; 27:103341. [PMID: 35988718 DOI: 10.1016/j.drudis.2022.103341] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 07/14/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022]
Abstract
The mRNA-based vaccines are quality-by-design (QbD) immunotherapies that provide safe, tunable, scalable, streamlined and potent treatment possibilities against different types of diseases. The self-amplifying mRNA (saRNA) vaccines, as a highly advantageous class of mRNA vaccines, are inspired by the intracellular self-multiplication nature of some positive-sense RNA viruses. Such vaccine platforms provide a relatively increased expression level of vaccine antigen(s) together with self-adjuvanticity properties. Lined with the QbD saRNA vaccines, essential optimizations improve the stability, safety, and immunogenicity of the vaccine constructs. Here, we elaborate on the concepts and mode-of-action of mRNA and saRNA vaccines, articulate the potential limitations or technical bottlenecks, and explain possible solutions or optimization methods in the process of their design and development.
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Affiliation(s)
- Mohammad M Pourseif
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yosef Masoudi-Sobhanzadeh
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Erfan Azari
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sepideh Parvizpour
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Jaleh Barar
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Rais Ansari
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida, USA
| | - Yadollah Omidi
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida, USA.
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26
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Ramaswamy K, Rashid M, Ramasamy S, Jayavelu T, Venkataraman S. Revisiting Viral RNA-Dependent RNA Polymerases: Insights from Recent Structural Studies. Viruses 2022; 14:2200. [PMID: 36298755 DOI: 10.3390/v14102200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022] Open
Abstract
RNA-dependent RNA polymerases (RdRPs) represent a distinctive yet versatile class of nucleic acid polymerases encoded by RNA viruses for the replication and transcription of their genome. The structure of the RdRP is comparable to that of a cupped right hand consisting of fingers, palm, and thumb subdomains. Despite the presence of a common structural core, the RdRPs differ significantly in the mechanistic details of RNA binding and polymerization. The present review aims at exploring these incongruities in light of recent structural studies of RdRP complexes with diverse cofactors, RNA moieties, analogs, and inhibitors.
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27
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Tajwar R, Bradley DP, Ponzar NL, Tavis JE. Predicted structure of the hepatitis B virus polymerase reveals an ancient conserved protein fold. Protein Sci 2022; 31:e4421. [PMID: 36173165 PMCID: PMC9601786 DOI: 10.1002/pro.4421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 11/12/2022]
Abstract
Hepatitis B virus (HBV) chronically infects >250 million people. It replicates by a unique protein-primed reverse transcription mechanism, and the primary anti-HBV drugs are nucleos(t)ide analogs targeting the viral polymerase (P). P has four domains compared to only two in most reverse transcriptases: the terminal protein (TP) that primes DNA synthesis, a spacer, the reverse transcriptase (RT), and the ribonuclease H (RNase H). Despite being a major drug target and catalyzing a reverse transcription pathway very different from the retroviruses, HBV P has resisted structural analysis for decades. Here, we exploited computational advances to model P. The TP wrapped around the RT domain rather than forming the anticipated globular domain, with the priming tyrosine poised over the RT active site. The orientation of the RT and RNase H domains resembled that of the retroviral enzymes despite the lack of sequences analogous to the retroviral linker region. The model was validated by mapping residues with known surface exposures, docking nucleic acids, mechanistically interpreting mutations with strong phenotypes, and docking inhibitors into the RT and RNase H active sites. The HBV P fold, including the orientation of the TP domain, was conserved among hepadnaviruses infecting rodent to fish hosts and a nackednavirus, but not in other non-retroviral RTs. Therefore, this protein fold has persisted since the hepadnaviruses diverged from nackednaviruses >400 million years ago. This model will advance mechanistic analyses into the poorly understood enzymology of HBV reverse transcription and will enable drug development against non-active site targets for the first time.
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Affiliation(s)
- Razia Tajwar
- Department of Molecular Microbiology and Immunology, School of Medicine and Institute for Drug and Biotherapeutic InnovationSaint Louis UniversitySaint LouisMissouriUSA
| | - Daniel P. Bradley
- Department of Molecular Microbiology and Immunology, School of Medicine and Institute for Drug and Biotherapeutic InnovationSaint Louis UniversitySaint LouisMissouriUSA
| | - Nathan L. Ponzar
- Department of Molecular Microbiology and Immunology, School of Medicine and Institute for Drug and Biotherapeutic InnovationSaint Louis UniversitySaint LouisMissouriUSA
| | - John E. Tavis
- Department of Molecular Microbiology and Immunology, School of Medicine and Institute for Drug and Biotherapeutic InnovationSaint Louis UniversitySaint LouisMissouriUSA
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28
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Campagnola G, Govindarajan V, Pelletier A, Canard B, Peersen OB. The SARS-CoV nsp12 Polymerase Active Site Is Tuned for Large-Genome Replication. J Virol 2022; 96:e0067122. [PMID: 35924919 PMCID: PMC9400494 DOI: 10.1128/jvi.00671-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/06/2022] [Indexed: 01/18/2023] Open
Abstract
Positive-strand RNA viruses replicate their genomes using virally encoded RNA-dependent RNA polymerases (RdRP) with a common active-site structure and closure mechanism upon which replication speed and fidelity can evolve to optimize virus fitness. Coronaviruses (CoV) form large multicomponent RNA replication-transcription complexes containing a core RNA synthesis machine made of the nsp12 RdRP protein with one nsp7 and two nsp8 proteins as essential subunits required for activity. We show that assembly of this complex can be accelerated 5-fold by preincubation of nsp12 with nsp8 and further optimized with the use of a novel nsp8L7 heterodimer fusion protein construct. Using rapid kinetics methods, we measure elongation rates of up to 260 nucleotides (nt)/s for the core replicase, a rate that is unusually fast for a viral polymerase. To address the origin of this fast rate, we examined the roles of two CoV-specific residues in the RdRP active site: Ala547, which replaces a conserved glutamate above the bound NTP, and Ser759, which mutates the palm domain GDD sequence to SDD. Our data show that Ala547 allows for a doubling of replication rate, but this comes at a fidelity cost that is mitigated by using a SDD sequence in the palm domain. Our biochemical data suggest that fixation of mutations in polymerase motifs F and C played a key role in nidovirus evolution by tuning replication rate and fidelity to accommodate their large genomes. IMPORTANCE Replicating large genomes represents a challenge for RNA viruses because fast RNA synthesis is needed to escape innate immunity defenses, but faster polymerases are inherently low-fidelity enzymes. Nonetheless, the coronaviruses replicate their ≈30-kb genomes using the core polymerase structure and mechanism common to all positive-strand RNA viruses. The classic explanation for their success is that the large-genome nidoviruses have acquired an exonuclease-based repair system that compensates for the high polymerase mutation rate. In this work, we establish that the nidoviral polymerases themselves also play a key role in maintaining genome integrity via mutations at two key active-site residues that enable very fast replication rates while maintaining typical mutation rates. Our findings further demonstrate the evolutionary plasticity of the core polymerase platform by showing how it has adapted during the expansion from short-genome picornaviruses to long-genome nidoviruses.
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Affiliation(s)
- Grace Campagnola
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Vishnu Govindarajan
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Annelise Pelletier
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Bruno Canard
- Centre National de la Recherche Scientifique, Aix-Marseille Université CNRS UMR 7257, AFMB, Marseille, France
| | - Olve B. Peersen
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
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29
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Singh AK, De Wijngaert B, Bijnens M, Uyttersprot K, Nguyen H, Martinez SE, Schols D, Herdewijn P, Pannecouque C, Arnold E, Das K. Cryo-EM structures of wild-type and E138K/M184I mutant HIV-1 RT/DNA complexed with inhibitors doravirine and rilpivirine. Proc Natl Acad Sci U S A 2022; 119:e2203660119. [PMID: 35858448 DOI: 10.1073/pnas.2203660119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The enzyme reverse transcriptase (RT) is a key antiviral target, and nonnucleoside RT inhibitors (NNRTIs) are among the frequently used components of antiretroviral therapy for treating HIV-1 infection. The emergence of drug-resistant mutations continues to pose a challenge in HIV treatment. The RT mutations M184I and E138K emerge in patients receiving rilpivirine. We obtained the structural snapshots of rilpivirine, doravirine, and nevirapine inhibited wild-type and M184I/E138K RT/DNA polymerase complexes by cryo-electron microscopy. Key structural changes observed in the rilpivirine- and doravirine-bound structures have implications for understanding NNRTI drug resistance. Additionally, the cryo-EM structure determination strategy outlined in this study can be adapted to aid drug design targeting smaller and flexible proteins. Structures trapping a variety of functional and conformational states of HIV-1 reverse transcriptase (RT) have been determined by X-ray crystallography. These structures have played important roles in explaining the mechanisms of catalysis, inhibition, and drug resistance and in driving drug design. However, structures of several desired complexes of RT could not be obtained even after many crystallization or crystal soaking experiments. The ternary complexes of doravirine and rilpivirine with RT/DNA are such examples. Structural study of HIV-1 RT by single-particle cryo-electron microscopy (cryo-EM) has been challenging due to the enzyme’s relatively smaller size and higher flexibility. We optimized a protocol for rapid structure determination of RT complexes by cryo-EM and determined six structures of wild-type and E138K/M184I mutant RT/DNA in complexes with the nonnucleoside inhibitors rilpivirine, doravirine, and nevirapine. RT/DNA/rilpivirine and RT/DNA/doravirine complexes have structural differences between them and differ from the typical conformation of nonnucleoside RT inhibitor (NNRTI)–bound RT/double-stranded DNA (dsDNA), RT/RNA–DNA, and RT/dsRNA complexes; the primer grip in RT/DNA/doravirine and the YMDD motif in RT/DNA/rilpivirine have large shifts. The DNA primer 3′-end in the doravirine-bound structure is positioned at the active site, but the complex is in a nonproductive state. In the mutant RT/DNA/rilpivirine structure, I184 is stacked with the DNA such that their relative positioning can influence rilpivirine in the pocket. Simultaneously, E138K mutation opens the NNRTI-binding pocket entrance, potentially contributing to a faster rate of rilpivirine dissociation by E138K/M184I mutant RT, as reported by an earlier kinetic study. These structural differences have implications for understanding molecular mechanisms of drug resistance and for drug design.
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30
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Rodríguez-Molina JB, O'Reilly FJ, Fagarasan H, Sheekey E, Maslen S, Skehel JM, Rappsilber J, Passmore LA. Mpe1 senses the binding of pre-mRNA and controls 3' end processing by CPF. Mol Cell 2022; 82:2490-2504.e12. [PMID: 35584695 PMCID: PMC9380774 DOI: 10.1016/j.molcel.2022.04.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 03/23/2022] [Accepted: 04/18/2022] [Indexed: 12/14/2022]
Abstract
Most eukaryotic messenger RNAs (mRNAs) are processed at their 3' end by the cleavage and polyadenylation specificity factor (CPF/CPSF). CPF mediates the endonucleolytic cleavage of the pre-mRNA and addition of a polyadenosine (poly(A)) tail, which together define the 3' end of the mature transcript. The activation of CPF is highly regulated to maintain the fidelity of RNA processing. Here, using cryo-EM of yeast CPF, we show that the Mpe1 subunit directly contacts the polyadenylation signal sequence in nascent pre-mRNA. The region of Mpe1 that contacts RNA also promotes the activation of CPF endonuclease activity and controls polyadenylation. The Cft2 subunit of CPF antagonizes the RNA-stabilized configuration of Mpe1. In vivo, the depletion or mutation of Mpe1 leads to widespread defects in transcription termination by RNA polymerase II, resulting in transcription interference on neighboring genes. Together, our data suggest that Mpe1 plays a major role in accurate 3' end processing, activating CPF, and ensuring timely transcription termination.
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Affiliation(s)
| | - Francis J O'Reilly
- Technische Universität Berlin, Chair of Bioanalytics, 10623 Berlin, Germany
| | | | | | - Sarah Maslen
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - J Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Juri Rappsilber
- Technische Universität Berlin, Chair of Bioanalytics, 10623 Berlin, Germany; Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
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31
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Pley C, Lourenço J, McNaughton AL, Matthews PC. Spacer Domain in Hepatitis B Virus Polymerase: Plugging a Hole or Performing a Role? J Virol 2022; 96:e0005122. [PMID: 35412348 PMCID: PMC9093120 DOI: 10.1128/jvi.00051-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
Hepatitis B virus (HBV) polymerase is divided into terminal protein, spacer, reverse transcriptase, and RNase domains. Spacer has previously been considered dispensable, merely acting as a tether between other domains or providing plasticity to accommodate deletions and mutations. We explore evidence for the role of spacer sequence, structure, and function in HBV evolution and lineage, consider its associations with escape from drugs, vaccines, and immune responses, and review its potential impacts on disease outcomes.
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Affiliation(s)
- Caitlin Pley
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - José Lourenço
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
| | - Anna L. McNaughton
- Population Health Science, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
| | - Philippa C. Matthews
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Division of Infection and Immunity, University College London, London, United Kingdom
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32
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Deval J, Gurard-Levin ZA. Opportunities and Challenges in Targeting the Proofreading Activity of SARS-CoV-2 Polymerase Complex. Molecules 2022; 27:molecules27092918. [PMID: 35566268 PMCID: PMC9103157 DOI: 10.3390/molecules27092918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/29/2022] [Accepted: 04/30/2022] [Indexed: 01/01/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic. While the development of vaccines and the emergence of antiviral therapeutics is promising, alternative strategies to combat COVID-19 (and potential future pandemics) remain an unmet need. Coronaviruses feature a unique mechanism that may present opportunities for therapeutic intervention: the RNA polymerase complex of coronaviruses is distinct in its ability to proofread and remove mismatched nucleotides during genome replication and transcription. The proofreading activity has been linked to the exonuclease (ExoN) activity of non-structural protein 14 (NSP14). Here, we review the role of NSP14, and other NSPs, in SARS-CoV-2 replication and describe the assays that have been developed to assess the ExoN function. We also review the nucleoside analogs and non-nucleoside inhibitors known to interfere with the proofreading activity of NSP14. Although not yet validated, the potential use of non-nucleoside proofreading inhibitors in combination with chain-terminating nucleosides may be a promising avenue for the development of anti-CoV agents.
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Affiliation(s)
- Jerome Deval
- Aligos Therapeutics, Inc., San Francisco, CA 94080, USA
- Correspondence:
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33
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Wanderley CWS, Correa TS, Scaranti M, Cunha FQ, Barroso-Sousa R. Targeting PARP1 to Enhance Anticancer Checkpoint Immunotherapy Response: Rationale and Clinical Implications. Front Immunol 2022; 13:816642. [PMID: 35572596 PMCID: PMC9094400 DOI: 10.3389/fimmu.2022.816642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Reinvigorating the antitumor immune response using immune checkpoint inhibitors (ICIs) has revolutionized the treatment of several malignancies. However, extended use of ICIs has resulted in a cancer-specific response. In tumors considered to be less immunogenic, the response rates were low or null. To overcome resistance and improve the beneficial effects of ICIs, novel strategies focused on ICI-combined therapies have been tested. In particular, poly ADP-ribose polymerase inhibitors (PARPi) are a class of agents with potential for ICI combined therapy. PARPi impairs single-strand break DNA repair; this mechanism involves synthetic lethality in tumor cells with deficient homologous recombination. More recently, novel evidence indicated that PAPRi has the potential to modulate the antitumor immune response by activating antigen-presenting cells, infiltrating effector lymphocytes, and upregulating programmed death ligand-1 in tumors. This review covers the current advances in the immune effects of PARPi, explores the potential rationale for combined therapy with ICIs, and discusses ongoing clinical trials.
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Affiliation(s)
- Carlos Wagner S. Wanderley
- Center for Research in Inflammatory Diseases (CRID), Ribeirao Preto Medical School, Ribeirao Preto, Brazil
- Department of Pharmacology, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil
| | | | | | - Fernando Queiroz Cunha
- Center for Research in Inflammatory Diseases (CRID), Ribeirao Preto Medical School, Ribeirao Preto, Brazil
- Department of Pharmacology, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, Brazil
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34
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Yu M, Sun L, Zhang Z, Zhang Y, Zhang H, Na L, Wang X. KPNA6 is a Cofactor of ANP32A/B in Supporting Influenza Virus Polymerase Activity. Microbiol Spectr 2022; 10:e0207321. [PMID: 35044222 PMCID: PMC8768627 DOI: 10.1128/spectrum.02073-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Influenza A virus (IAV) RNA-dependent RNA polymerase (vPol) is a heterotrimer composed of PB2, PB1, and PA, which, together with vRNA and nucleoprotein (NP), forms viral ribonucleoprotein (vRNP) complex to direct the transcription and replication of the viral genome. Host factor ANP32 proteins have been proved to be associated with vRNP and are essential for polymerase activity and cross-species restriction of avian influenza virus. However, the molecular mechanism by which ANP32 supports polymerase activity is largely unknown. Here, we identified that KPNA6 is associated with ANP32A/B and vRNP of the influenza virus. Both knockout and overexpression of KPNA6 downregulate the replication of the influenza virus by inhibiting the polymerase activity, indicating that a certain level of KPNA6 is beneficial for efficient replication of the influenza virus. Furthermore, we demonstrate that overexpression of KPNA6 or its nuclear importing domain negative mutation inhibited the interaction between ANP32 and vRNP, thus reducing the polymerase activity. Our results revealed the role of KPNA6 in interacting with both ANP32A/B and vRNP to maintain viral polymerase activity and provided new insights for further understanding of the mechanism by which ANP32 supports influenza polymerase. IMPORTANCE Host factor ANP32 plays a fundamental role in supporting the polymerase activity of influenza viruses, but the underlying mechanism is largely unknown. Here, we propose that KPNA6 is involved in the function of ANP32A/B to support influenza virus polymerase by interacting with both vRNP and ANP32A/B. The proper amount of KPNA6 and ANP32 proteins in the KPNA6-ANP32-vRNP complex is crucial for maintaining the viral polymerase activity. The KPNA6 may contribute to maintaining stable interaction between vRNA and ANP32 proteins in the nucleus, and this function is independent of the known importing domain of KPNA6. Our research reveals a role of KNPA6 associated with ANP32 proteins that support the viral polymerase and suggests a new perspective for developing antiviral strategies.
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Affiliation(s)
- Mengmeng Yu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Liuke Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhenyu Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuan Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Haili Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lei Na
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, China
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35
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Park KR, Kim YE, Shamim A, Gong S, Choi SH, Kim KK, Kim YJ, Ahn JH. Analysis of Novel Drug-Resistant Human Cytomegalovirus DNA Polymerase Mutations Reveals the Role of a DNA-Binding Loop in Phosphonoformic Acid Resistance. Front Microbiol 2022; 13:771978. [PMID: 35185843 PMCID: PMC8851065 DOI: 10.3389/fmicb.2022.771978] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/13/2022] [Indexed: 12/19/2022] Open
Abstract
The appearance of drug-resistant mutations in UL54 DNA polymerase and UL97 kinase genes is problematic for the treatment of human cytomegalovirus (HCMV) diseases. During treatment of HCMV infection in a pediatric hematopoietic cell transplant recipient, H600L and T700A mutations and E576G mutation were independently found in the UL54 gene. Foscarnet (FOS; phosphonoformic acid) resistance by T700A mutation is reported. Here, we investigated the role of novel mutations in drug resistance by producing recombinant viruses and a model polymerase structure. The H600L mutant virus showed an increase in resistance to ganciclovir (GCV) by 11-fold and to FOS and cidofovir (CDV) by 5-fold, compared to the wild type, while the E756G mutant virus showed an increase in resistance to FOS by 9-fold and modestly to CDV by 2-fold. With the FOS-resistant T700A mutation, only H600L produced increased FOS resistance up to 37-fold, indicating an additive effect of these mutations on FOS resistance. To gain insight into drug resistance mechanisms, a model structure for UL54 polymerase was constructed using the yeast DNA polymerase as a template. In this model, HCMV DNA polymerase contains a long palm loop domain of which H600 and T700 are located on each end and T700 interacts with the FOS binding pocket. Our results demonstrate that H600L and E756G mutations in UL54 polymerase are novel drug-resistant mutations and that the acquisition of both H600L and T700A mutations in the DNA-binding loop confers increased resistance to FOS treatment, providing novel insights for the mechanism acquiring foscarnet resistance.
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Affiliation(s)
- Kye Ryeong Park
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Young-Eui Kim
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Amen Shamim
- Department of Precision Medicine, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea.,Department of Computer Science, University of Agriculture, Faisalabad, Pakistan
| | - Shuang Gong
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Soo-Han Choi
- Department of Pediatrics, Pusan National University Hospital, Busan, South Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, South Korea
| | - Yae-Jean Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jin-Hyun Ahn
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, South Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, South Korea
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36
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Yuan H, Wang Y, Liu XP. The thumb subdomain of Pyrococcus furiosus DNA polymerase is responsible for deoxyuracil binding, hydrolysis and polymerization of nucleotides. Int J Biochem Cell Biol 2022; 144:106171. [PMID: 35093572 DOI: 10.1016/j.biocel.2022.106171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/02/2022] [Accepted: 01/24/2022] [Indexed: 11/26/2022]
Abstract
B-family DNA polymerases, which are found in eukaryotes, archaea, viruses, and some bacteria, participate in DNA replication and repair. Starting from the N-terminus of archaeal and bacterial B-family DNA polymerases, three domains include the N-terminal, exonuclease, and polymerase domains. The N-terminal domain of the archaeal B-family DNA polymerase has a conserved deoxyuracil-binding pocket for specially binding the deoxyuracil base on DNA. The exonuclease domain is responsible for removing the mismatched base pair. The polymerase domain is the core functional domain and takes a highly conserved structure composed of fingers, palm and thumb subdomains. Previous studies have demonstrated that the thumb subdomain mainly functions as a DNA-binding element and has coordination with the exonuclease domain and palm subdomain. To further elucidate the possible functions of the thumb subdomain of archaeal B-family DNA polymerases, the thumb subdomain of Pyrococcus furiosus DNA polymerase was mutated, and the effects on three activities were characterized. Our results demonstrate that the thumb subdomain participates in the three activities of archaeal B-family DNA polymerases as a common structural element. Both the N-terminal deoxyuracil-binding pocket and thumb subdomain are critical for deoxyuracil binding. Moreover, the thumb subdomain assists DNA polymerization and hydrolysis reactions, but it does not contribute to the fidelity of DNA polymerization.
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Affiliation(s)
- Hui Yuan
- Department of Thoracic Surgery, Fudan University Shanghai Cancer Center, Shanghai, China; Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, China
| | - You Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China
| | - Xi-Peng Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China; Joint International Research Laboratory of Metabolic & Developmental Sciences (Ministry of Education), Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China.
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37
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Boulard Y, Bressanelli S. Recapitulating Trafficking of Nucleosides Into the Active Site of Polymerases of RNA Viruses: The Challenge and the Prize. Front Med Technol 2022; 3:705875. [PMID: 35047945 PMCID: PMC8757734 DOI: 10.3389/fmedt.2021.705875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/18/2021] [Indexed: 11/30/2022] Open
Abstract
Nucleoside analogs are very effective antiviral agents with currently over 25 compounds approved for the therapy of viral infections. Still, their successful use against RNA viruses is very recent, despite RNA viruses comprising some of the most damaging human pathogens (e.g., Coronaviruses, Influenza viruses, or Flaviviridae such as dengue, Zika and hepatitis C viruses). The breakthrough came in 2013–2014, when the nucleoside analog Sofosbuvir became one of the cornerstones of current curative treatments for hepatitis C virus (HCV). An analog designed on the same principles, Remdesivir, has been the first approved compound against SARS-CoV-2, the coronavirus that causes the current COVID-19 pandemic. Both of these nucleoside analogs target the RNA-dependent RNA polymerase (RdRp) (NS5B for HCV, nsp12 for SARS-CoV-2). RdRps of RNA viruses display a peculiar elaboration of the classical polymerase architecture that leads to their active site being caged. Thus, triphosphate nucleosides and their analogs must access this active site in several steps along a narrow and dynamic tunnel. This makes straightforward computational approaches such as docking unsuitable for getting atomic-level details of this process. Here we give an account of ribose-modified nucleoside analogs as inhibitors of viral RdRps and of why taking into account the dynamics of these polymerases is necessary to understand nucleotide selection by RdRps. As a case study we use a computational protocol we recently described to examine the approach of the NTP tunnel of HCV NS5B by cellular metabolites of Sofosbuvir. We find major differences with natural nucleotides even at this early stage of nucleotide entry.
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Affiliation(s)
- Yves Boulard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Stéphane Bressanelli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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38
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Pimentel SC, Upton HE, Collins K. Separable structural requirements for cDNA synthesis, nontemplated extension, and template jumping by a non-LTR retroelement reverse transcriptase. J Biol Chem 2022; 298:101624. [PMID: 35065960 PMCID: PMC8857657 DOI: 10.1016/j.jbc.2022.101624] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/16/2022] Open
Abstract
Broad evolutionary expansion of polymerase families has enabled specialization of their activities for distinct cellular roles. In addition to template-complementary synthesis, many polymerases extend their duplex products by nontemplated nucleotide addition (NTA). This activity is exploited for laboratory strategies of cloning and sequencing nucleic acids and could have important biological function, although the latter has been challenging to test without separation-of-function mutations. Several retroelement and retroviral reverse transcriptases (RTs) support NTA and also template jumping, by which the RT performs continuous complementary DNA (cDNA) synthesis using physically separate templates. Previous studies that aimed to dissect the relationship between NTA and template jumping leave open questions about structural requirements for each activity and their interdependence. Here, we characterize the structural requirements for cDNA synthesis, NTA, template jumping, and the unique terminal transferase activity of Bombyx mori R2 non-long terminal repeat retroelement RT. With sequence alignments and structure modeling to guide mutagenesis, we generated enzyme variants across motifs generally conserved or specific to RT subgroups. Enzyme variants had diverse NTA profiles not correlated with other changes in cDNA synthesis activity or template jumping. Using these enzyme variants and panels of activity assay conditions, we show that template jumping requires NTA. However, template jumping by NTA-deficient enzymes can be rescued using primer duplex with a specific length of 3′ overhang. Our findings clarify the relationship between NTA and template jumping as well as additional activities of non-long terminal repeat RTs, with implications for the specialization of RT biological functions and laboratory applications.
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Affiliation(s)
- Sydney C Pimentel
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Heather E Upton
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA.
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39
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Abstract
High fidelity (HiFi) DNA polymerases (Pols) perform the bulk of DNA synthesis required to duplicate genomes in all forms of life. Their structural features, enzymatic mechanisms, and inherent properties are well-described over several decades of research. HiFi Pols are so accurate that they become stalled at sites of DNA damage or lesions that are not one of the four canonical DNA bases. Once stalled, the replisome becomes compromised and vulnerable to further DNA damage. One mechanism to relieve stalling is to recruit a translesion synthesis (TLS) Pol to rapidly synthesize over and past the damage. These TLS Pols have good specificities for the lesion but are less accurate when synthesizing opposite undamaged DNA, and so, mechanisms are needed to limit TLS Pol synthesis and recruit back a HiFi Pol to reestablish the replisome. The overall TLS process can be complicated with several cellular Pols, multifaceted protein contacts, and variable nucleotide incorporation kinetics all contributing to several discrete substitution (or template hand-off) steps. In this review, we highlight the mechanistic differences between distributive equilibrium exchange events and concerted contact-dependent switching by DNA Pols for insertion, extension, and resumption of high-fidelity synthesis beyond the lesion.
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40
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Bagshaw CR, Hentschel J, Stone MD. The Processivity of Telomerase: Insights from Kinetic Simulations and Analyses. Molecules 2021; 26:7532. [PMID: 34946615 PMCID: PMC8705835 DOI: 10.3390/molecules26247532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022] Open
Abstract
Telomerases are moderately processive reverse transcriptases that use an integral RNA template to extend the 3' end of linear chromosomes. Processivity values, defined as the probability of extension rather than dissociation, range from about 0.7 to 0.99 at each step. Consequently, an average of tens to hundreds of nucleotides are incorporated before the single-stranded sDNA product dissociates. The RNA template includes a six nucleotide repeat, which must be reset in the active site via a series of translocation steps. Nucleotide addition associated with a translocation event shows a lower processivity (repeat addition processivity, RAP) than that at other positions (nucleotide addition processivity, NAP), giving rise to a characteristic strong band every 6th position when the product DNA is analyzed by gel electrophoresis. Here, we simulate basic reaction mechanisms and analyze the product concentrations using several standard procedures to show how the latter can give rise to systematic errors in the processivity estimate. Complete kinetic analysis of the time course of DNA product concentrations following a chase with excess unlabeled DNA primer (i.e., a pulse-chase experiment) provides the most rigorous approach. This analysis reveals that the higher product concentrations associated with RAP arise from a stalling of nucleotide incorporation reaction during translocation rather than an increased rate constant for the dissociation of DNA from the telomerase.
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Affiliation(s)
- Clive R. Bagshaw
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
| | - Jendrik Hentschel
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
- Element Biosciences, 9880 Campus Point Drive, San Diego, CA 92121, USA
| | - Michael D. Stone
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
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41
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Das SK, Kuzin V, Cameron DP, Sanford S, Jha RK, Nie Z, Rosello MT, Holewinski R, Andresson T, Wisniewski J, Natsume T, Price DH, Lewis BA, Kouzine F, Levens D, Baranello L. MYC assembles and stimulates topoisomerases 1 and 2 in a "topoisome". Mol Cell 2021; 82:140-158.e12. [PMID: 34890565 DOI: 10.1016/j.molcel.2021.11.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 08/11/2021] [Accepted: 11/13/2021] [Indexed: 12/25/2022]
Abstract
High-intensity transcription and replication supercoil DNA to levels that can impede or halt these processes. As a potent transcription amplifier and replication accelerator, the proto-oncogene MYC must manage this interfering torsional stress. By comparing gene expression with the recruitment of topoisomerases and MYC to promoters, we surmised a direct association of MYC with topoisomerase 1 (TOP1) and TOP2 that was confirmed in vitro and in cells. Beyond recruiting topoisomerases, MYC directly stimulates their activities. We identify a MYC-nucleated "topoisome" complex that unites TOP1 and TOP2 and increases their levels and activities at promoters, gene bodies, and enhancers. Whether TOP2A or TOP2B is included in the topoisome is dictated by the presence of MYC versus MYCN, respectively. Thus, in vitro and in cells, MYC assembles tools that simplify DNA topology and promote genome function under high output conditions.
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Affiliation(s)
- Subhendu K Das
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Vladislav Kuzin
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Donald P Cameron
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Suzanne Sanford
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Rajiv Kumar Jha
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Zuqin Nie
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Marta Trullols Rosello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Ronald Holewinski
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Bethesda, MD 21701, USA
| | - Thorkell Andresson
- Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Bethesda, MD 21701, USA
| | - Jan Wisniewski
- Confocal Microscopy and Digital Imaging Facility, National Cancer Institute, Bethesda, MD 20892, USA
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Shizuoka 411-8540, Japan; Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - David H Price
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Brian A Lewis
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA
| | - David Levens
- Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20814, USA.
| | - Laura Baranello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
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Amare B, Mo A, Khan N, Sowa DJ, Warner MM, Tetenych A, Andres SN. LigD: A Structural Guide to the Multi-Tool of Bacterial Non-Homologous End Joining. Front Mol Biosci 2021; 8:787709. [PMID: 34901162 PMCID: PMC8656161 DOI: 10.3389/fmolb.2021.787709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/08/2021] [Indexed: 11/27/2022] Open
Abstract
DNA double-strand breaks are the most lethal form of damage for living organisms. The non-homologous end joining (NHEJ) pathway can repair these breaks without the use of a DNA template, making it a critical repair mechanism when DNA is not replicating, but also a threat to genome integrity. NHEJ requires proteins to anchor the DNA double-strand break, recruit additional repair proteins, and then depending on the damage at the DNA ends, fill in nucleotide gaps or add or remove phosphate groups before final ligation. In eukaryotes, NHEJ uses a multitude of proteins to carry out processing and ligation of the DNA double-strand break. Bacterial NHEJ, though, accomplishes repair primarily with only two proteins-Ku and LigD. While Ku binds the initial break and recruits LigD, it is LigD that is the primary DNA end processing machinery. Up to three enzymatic domains reside within LigD, dependent on the bacterial species. These domains are a polymerase domain, to fill in nucleotide gaps with a preference for ribonucleotide addition; a phosphoesterase domain, to generate a 3'-hydroxyl DNA end; and the ligase domain, to seal the phosphodiester backbone. To date, there are no experimental structures of wild-type LigD, but there are x-ray and nuclear magnetic resonance structures of the individual enzymatic domains from different bacteria and archaea, along with structural predictions of wild-type LigD via AlphaFold. In this review, we will examine the structures of the independent domains of LigD from different bacterial species and the contributions these structures have made to understanding the NHEJ repair mechanism. We will then examine how the experimental structures of the individual LigD enzymatic domains combine with structural predictions of LigD from different bacterial species and postulate how LigD coordinates multiple enzymatic activities to carry out DNA double-strand break repair in bacteria.
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Affiliation(s)
- Benhur Amare
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Anthea Mo
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Noorisah Khan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Dana J. Sowa
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Monica M. Warner
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Andriana Tetenych
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Sara N. Andres
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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Wiegard A, Kuzin V, Cameron DP, Grosser J, Ceribelli M, Mehmood R, Ballarino R, Valant F, Grochowski R, Karabogdan I, Crosetto N, Lindqvist A, Bizard AH, Kouzine F, Natsume T, Baranello L. Topoisomerase 1 activity during mitotic transcription favors the transition from mitosis to G1. Mol Cell 2021; 81:5007-5024.e9. [PMID: 34767771 DOI: 10.1016/j.molcel.2021.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/26/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
As cells enter mitosis, chromatin compacts to facilitate chromosome segregation yet remains transcribed. Transcription supercoils DNA to levels that can impede further progression of RNA polymerase II (RNAPII) unless it is removed by DNA topoisomerase 1 (TOP1). Using ChIP-seq on mitotic cells, we found that TOP1 is required for RNAPII translocation along genes. The stimulation of TOP1 activity by RNAPII during elongation allowed RNAPII clearance from genes in prometaphase and enabled chromosomal segregation. Disruption of the TOP1-RNAPII interaction impaired RNAPII spiking at promoters and triggered defects in the post-mitotic transcription program. This program includes factors necessary for cell growth, and cells with impaired TOP1-RNAPII interaction are more sensitive to inhibitors of mTOR signaling. We conclude that TOP1 is necessary for assisting transcription during mitosis with consequences for growth and gene expression long after mitosis is completed. In this sense, TOP1 ensures that cellular memory is preserved in subsequent generations.
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Affiliation(s)
- Anika Wiegard
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Vladislav Kuzin
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Donald P Cameron
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Jan Grosser
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Michele Ceribelli
- Division of Pre-Clinical Innovation, NCATS, National Institutes of Health, Rockville, MD 20850, USA
| | - Rashid Mehmood
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden; Department of Software Engineering, University of Kotli, AJ&K, 45320 Kotli Azad Kashmir, Pakistan
| | - Roberto Ballarino
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Francesco Valant
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Radosław Grochowski
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | | | - Nicola Crosetto
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Arne Lindqvist
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Anna Helene Bizard
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Toyoaki Natsume
- Department of Chromosome Science, National Institute of Genetics, Shizuoka 411-8540, Japan; Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Laura Baranello
- Department of Cell and Molecular Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
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44
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Obi JO, Gutiérrez-Barbosa H, Chua JV, Deredge DJ. Current Trends and Limitations in Dengue Antiviral Research. Trop Med Infect Dis 2021; 6:180. [PMID: 34698303 DOI: 10.3390/tropicalmed6040180] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022] Open
Abstract
Dengue is the most prevalent arthropod-borne viral disease worldwide and affects approximately 2.5 billion people living in over 100 countries. Increasing geographic expansion of Aedes aegypti mosquitoes (which transmit the virus) has made dengue a global health concern. There are currently no approved antivirals available to treat dengue, and the only approved vaccine used in some countries is limited to seropositive patients. Treatment of dengue, therefore, remains largely supportive to date; hence, research efforts are being intensified for the development of antivirals. The nonstructural proteins, 3 and 5 (NS3 and NS5), have been the major targets for dengue antiviral development due to their indispensable enzymatic and biological functions in the viral replication process. NS5 is the largest and most conserved nonstructural protein encoded by flaviviruses. Its multifunctionality makes it an attractive target for antiviral development, but research efforts have, this far, not resulted in the successful development of an antiviral targeting NS5. Increase in structural insights into the dengue NS5 protein will accelerate drug discovery efforts focused on NS5 as an antiviral target. In this review, we will give an overview of the current state of therapeutic development, with a focus on NS5 as a therapeutic target against dengue.
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Carvalho G, Díaz-Talavera A, Calvo PA, Blanco L, Martínez-Jiménez MI. Human PrimPol Discrimination against Dideoxynucleotides during Primer Synthesis. Genes (Basel) 2021; 12:1487. [PMID: 34680882 DOI: 10.3390/genes12101487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 12/02/2022] Open
Abstract
PrimPol is required to re-prime DNA replication at both nucleus and mitochondria, thus facilitating fork progression during replicative stress. ddC is a chain-terminating nucleotide that has been widely used to block mitochondrial DNA replication because it is efficiently incorporated by the replicative polymerase Polγ. Here, we show that human PrimPol discriminates against dideoxynucleotides (ddNTP) when elongating a primer across 8oxoG lesions in the template, but also when starting de novo synthesis of DNA primers, and especially when selecting the 3′nucleotide of the initial dimer. PrimPol incorporates ddNTPs with a very low efficiency compared to dNTPs even in the presence of activating manganese ions, and only a 40-fold excess of ddNTP would significantly disturb PrimPol primase activity. This discrimination against ddNTPs prevents premature termination of the primers, warranting their use for elongation. The crystal structure of human PrimPol highlights Arg291 residue as responsible for the strong dNTP/ddNTP selectivity, since it interacts with the 3′-OH group of the incoming deoxynucleotide, absent in ddNTPs. Arg291, shown here to be critical for both primase and polymerase activities of human PrimPol, would contribute to the preferred binding of dNTPs versus ddNTPs at the 3′elongation site, thus avoiding synthesis of abortive primers.
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Abstract
Bacteriophages have long been model systems to study the molecular mechanisms of DNA replication. During DNA replication, a DNA helicase and a DNA polymerase cooperatively unwind the parental DNA. By surveying recent data from three bacteriophage replication systems, we summarized the mechanistic basis of DNA replication by helicases and polymerases. Kinetic data have suggested that a polymerase or a helicase alone is a passive motor that is sensitive to the base-pairing energy of the DNA. When coupled together, the helicase-polymerase complex is able to unwind DNA actively. In bacteriophage T7, helicase and polymerase reside right at the replication fork where the parental DNA is separated into two daughter strands. The two motors pull the two daughter strands to opposite directions, while the polymerase provides a separation pin to split the fork. Although independently evolved and containing different replisome components, bacteriophage T4 replisome shares mechanistic features of Hel-Pol coupling that are similar to T7. Interestingly, in bacteriophages with a limited size of genome like Φ29, DNA polymerase itself can form a tunnel-like structure, which encircles the DNA template strand and facilitates strand displacement synthesis in the absence of a helicase. Studies on bacteriophage replication provide implications for the more complicated replication systems in bacteria, archaeal, and eukaryotic systems, as well as the RNA genome replication in RNA viruses.
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Affiliation(s)
| | - Yang Gao
- Correspondence: ; Tel.: +1-713-348-2619
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Ohsaki E, Suwanmanee Y, Ueda K. Chronic Hepatitis B Treatment Strategies Using Polymerase Inhibitor-Based Combination Therapy. Viruses 2021; 13:v13091691. [PMID: 34578273 PMCID: PMC8473100 DOI: 10.3390/v13091691] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/19/2021] [Accepted: 08/25/2021] [Indexed: 12/12/2022] Open
Abstract
Viral polymerase is an essential enzyme for the amplification of the viral genome and is one of the major targets of antiviral therapies. However, a serious concern to be solved in hepatitis B virus (HBV) infection is the difficulty of eliminating covalently closed circular (ccc) DNA. More recently, therapeutic strategies targeting various stages of the HBV lifecycle have been attempted. Although cccDNA-targeted therapies are attractive, there are still many problems to be overcome, and the development of novel polymerase inhibitors remains an important issue. Interferons and nucleos(t)ide reverse transcriptase inhibitors (NRTIs) are the only therapeutic options currently available for HBV infection. Many studies have reported that the combination of interferons and NRTI causes the loss of hepatitis B surface antigen (HBsAg), which is suggestive of seroconversion. Although NRTIs do not directly target cccDNA, they can strongly reduce the serum viral DNA load and could suppress the recycling step of cccDNA formation, improve liver fibrosis/cirrhosis, and reduce the risk of hepatocellular carcinoma. Here, we review recent studies on combination therapies using polymerase inhibitors and discuss the future directions of therapeutic strategies for HBV infection.
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Sáez-Álvarez Y, Jiménez de Oya N, Del Águila C, Saiz JC, Arias A, Agudo R, Martín-Acebes MA. Novel Nonnucleoside Inhibitors of Zika Virus Polymerase Identified through the Screening of an Open Library of Antikinetoplastid Compounds. Antimicrob Agents Chemother 2021; 65:e0089421. [PMID: 34152807 DOI: 10.1128/AAC.00894-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Zika virus (ZIKV) is a mosquito-borne pathogen responsible for neurological disorders (Guillain-Barré syndrome) and congenital malformations (microcephaly). Its ability to cause explosive epidemics, such as that of 2015 to 2016, urges the identification of effective antiviral drugs. Viral polymerase inhibitors constitute one of the most successful fields in antiviral research. Accordingly, the RNA-dependent RNA polymerase activity of flavivirus nonstructural protein 5 (NS5) provides a unique target for the development of direct antivirals with high specificity and low toxicity. Here, we describe the discovery and characterization of two novel nonnucleoside inhibitors of ZIKV polymerase. These inhibitors, TCMDC-143406 (compound 6) and TCMDC-143215 (compound 15) were identified through the screening of an open-resource library of antikinetoplastid compounds using a fluorescence-based polymerization assay based on ZIKV NS5. The two compounds inhibited ZIKV NS5 polymerase activity in vitro and ZIKV multiplication in cell culture (half-maximal effective concentrations [EC50] values of 0.5 and 2.6 μM for compounds 6 and 15, respectively). Both compounds also inhibited the replication of other pathogenic flaviviruses, namely, West Nile virus (WNV; EC50 values of 4.3 and 4.6 μM for compounds 6 and 15, respectively) and dengue virus 2 (DENV-2; EC50 values of 3.4 and 9.6 μM for compounds 6 and 15, respectively). Enzymatic assays confirmed that the polymerase inhibition was produced by a noncompetitive mechanism. Combinatorial assays revealed an antagonistic effect between both compounds, suggesting that they would bind to the same region of ZIKV polymerase. The nonnucleoside inhibitors of ZIKV polymerase here described could constitute promising lead compounds for the development of anti-ZIKV therapies and, eventually, broad-spectrum antiflavivirus drugs.
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Cannon JL, Bonifacio J, Bucardo F, Buesa J, Bruggink L, Chan MCW, Fumian TM, Giri S, Gonzalez MD, Hewitt J, Lin JH, Mans J, Muñoz C, Pan CY, Pang XL, Pietsch C, Rahman M, Sakon N, Selvarangan R, Browne H, Barclay L, Vinjé J. Global Trends in Norovirus Genotype Distribution among Children with Acute Gastroenteritis. Emerg Infect Dis 2021; 27:1438-1445. [PMID: 33900173 PMCID: PMC8084493 DOI: 10.3201/eid2705.204756] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Noroviruses are a leading cause of acute gastroenteritis (AGE) among adults and children worldwide. NoroSurv is a global network for norovirus strain surveillance among children <5 years of age with AGE. Participants in 16 countries across 6 continents used standardized protocols for dual typing (genotype and polymerase type) and uploaded 1,325 dual-typed sequences to the NoroSurv web portal during 2016-2020. More than 50% of submitted sequences were GII.4 Sydney[P16] or GII.4 Sydney[P31] strains. Other common strains included GII.2[P16], GII.3[P12], GII.6[P7], and GI.3[P3] viruses. In total, 22 genotypes and 36 dual types, including GII.3 and GII.20 viruses with rarely reported polymerase types, were detected, reflecting high strain diversity. Surveillance data captured in NoroSurv enables the monitoring of trends in norovirus strains associated childhood AGE throughout the world on a near real-time basis.
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Soh YQS, Malone KD, Eguia RT, Bloom JD. Comprehensive Profiling of Mutations to Influenza Virus PB2 That Confer Resistance to the Cap-Binding Inhibitor Pimodivir. Viruses 2021; 13:1196. [PMID: 34206520 DOI: 10.3390/v13071196] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [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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