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Akira Naito - One of the best experts on this subject based on the ideXlab platform.
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synergistic antiviral activity of s 033188 s 033447 a novel inhibitor of influenza Virus cap dependent endonuclease in combination with neuraminidase inhibitors in vitro
Open Forum Infectious Diseases, 2017Co-Authors: Mitsutaka Kitano, Atsuko Yamamoto, Takeshi Noshi, Makoto Kawai, Ryu Yoshida, Akihiko Sato, Takao Shishido, Akira NaitoAbstract:Background S-033447, an active form of orally available prodrug S-033188, is a novel small molecule inhibitor of cap-dependent endonuclease that is essential for influenza Virus Transcription and replication. In this study, we evaluated the inhibitory effect of S-033188 in combination with neuraminidase inhibitors on the replication of influenza A/H1N1 Virus in cultured cells.
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Synergistic Antiviral Activity of S-033188/S-033447, a Novel Inhibitor of Influenza Virus Cap-Dependent Endonuclease, in Combination with Neuraminidase Inhibitors In Vitro.
Open Forum Infectious Diseases, 2017Co-Authors: Mitsutaka Kitano, Atsuko Yamamoto, Takeshi Noshi, Makoto Kawai, Ryu Yoshida, Akihiko Sato, Takao Shishido, Akira NaitoAbstract:Background S-033447, an active form of orally available prodrug S-033188, is a novel small molecule inhibitor of cap-dependent endonuclease that is essential for influenza Virus Transcription and replication. In this study, we evaluated the inhibitory effect of S-033188 in combination with neuraminidase inhibitors on the replication of influenza A/H1N1 Virus in cultured cells.
Stephan Becker - One of the best experts on this subject based on the ideXlab platform.
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Serine-Arginine Protein Kinase 1 Regulates Ebola Virus Transcription.
mBio, 2020Co-Authors: Yuki Takamatsu, Nadine Biedenkopf, Verena Kraehling, Larissa Kolesnikova, Sandro Halwe, Clemens Lier, Stefan Baumeister, Takeshi Noda, Stephan BeckerAbstract:Ebola Virus (EBOV) causes a severe and often fatal disease for which no approved vaccines or antivirals are currently available. EBOV VP30 has been described as a viral phosphoprotein, and nonphosphorylated VP30 is essential and sufficient to support secondary Transcription in an EBOV-specific minigenome system; however, phosphorylatable serine residues near the N terminus of VP30 are required to support primary viral Transcription as well as the reinitiation of VP30-mediated Transcription at internal EBOV genes. While the dephosphorylation of VP30 by the cellular phosphatase PP2A was found to be mediated by nucleoprotein, the VP30-specific kinases and the role of phosphorylation remain unknown. Here, we report that serine-arginine protein kinase 1 (SRPK1) and SRPK2 phosphorylate serine 29 of VP30, which is located in an N-terminal R26xxS29 motif. Interaction with VP30 via the R26xxS29 motif recruits SRPK1 into EBOV-induced inclusion bodies, the sites of viral RNA synthesis, and an inhibitor of SRPK1/SRPK2 downregulates primary viral Transcription. When the SRPK1 recognition motif of VP30 was mutated in a recombinant EBOV, Virus replication was severely impaired. It is presumed that the interplay between SRPK1 and PP2A in the EBOV inclusions provides a comprehensive regulatory circuit to ensure the activity of VP30 in EBOV Transcription. Thus, the identification of SRPK1 is an important mosaic stone that completes our picture of the players involved in Ebola Virus Transcription regulation.IMPORTANCE The largest Ebola Virus (EBOV) epidemic in West Africa ever caused more than 28,000 cases and 11,000 deaths, and the current EBOV epidemic in the Democratic Republic of the Congo continues, with more than 3,000 cases to date. Therefore, it is essential to develop antivirals against EBOV. Recently, an inhibitor of the cellular phosphatase PP2A-mediated dephosphorylation of the EBOV Transcription factor VP30 has been shown to suppress the spread of Ebola Virus. Here, we identified the protein kinase SRPK1 as a VP30-specific kinase that phosphorylates serine 29, the same residue that is dephosphorylated by PP2A. SRPK1-mediated phosphorylation of serine 29 enabled primary viral Transcription. Mutation of the SRPK1 recognition motif in VP30 resulted in significant growth inhibition of EBOV. Similarly, elevation of the phosphorylation status of serine 29 by overexpression of SRPK1 inhibited EBOV growth, highlighting the importance of reversible phosphorylation of VP30 as a potential therapeutic target.
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Serine-arginine protein kinase 1 regulates Ebola Virus Transcription
2019Co-Authors: Yuki Takamatsu, Nadine Biedenkopf, Verena Kraehling, Larissa Kolesnikova, Sandro Halwe, Clemens Lier, Stefan Baumeister, Takeshi Noda, Stephan BeckerAbstract:Abstract Ebola Virus (EBOV) causes a severe and often fatal disease for which no approved vaccines or antivirals are currently available. EBOV Transcription requires the sequential phosphorylation and dephosphorylation of the viral Transcription factor VP30. While dephosphorylation is carried out by phosphatases PP2A and PP1, the VP30-specific kinase is unknown. Here, we report that serine-arginine protein kinase 1 and 2 (SRPK1 and SRPK2) phosphorylate serine-29 of VP30, which is located in an N-terminal R26xxS29 motif. Interaction with VP30 via the R26xxS29 motif recruits SRPK1 into EBOV-induced inclusion bodies, the sites of viral RNA synthesis and an inhibitor of SRPK1/SRPK2 downregulates primary viral Transcription. When the SRPK1 recognition motif of VP30 was mutated in a recombinant EBOV, Virus replication was severely impaired. It is presumed that the interplay between SRPK1 and PP2A in the EBOV inclusions provides a comprehensive regulatory circuit to ensure the activity of VP30 in EBOV Transcription.
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RNA binding specificity of Ebola Virus Transcription factor VP30
RNA biology, 2016Co-Authors: Julia Schlereth, Nadine Biedenkopf, Stephan Becker, Arnold Grünweller, Roland K. HartmannAbstract:The Transcription factor VP30 of the non-segmented RNA negative strand Ebola Virus balances viral Transcription and replication. Here, we comprehensively studied RNA binding by VP30. Using a novel VP30:RNA electrophoretic mobility shift assay, we tested truncated variants of 2 potential natural RNA substrates of VP30 - the genomic Ebola viral 3'-leader region and its complementary antigenomic counterpart (each ∼155 nt in length) - and a series of other non-viral RNAs. Based on oligonucleotide interference, the major VP30 binding region on the genomic 3'-leader substrate was assigned to the internal expanded single-stranded region (∼ nt 125-80). Best binding to VP30 was obtained with ssRNAs of optimally ∼ 40 nt and mixed base composition; underrepresentation of purines or pyrimidines was tolerated, but homopolymeric sequences impaired binding. A stem-loop structure, particularly at the 3'-end or positioned internally, supports stable binding to VP30. In contrast, dsRNA or RNAs exposing large internal loops flanked by entirely helical arms on both sides are not bound. Introduction of a 5´-Cap(0) structure impaired VP30 binding. Also, ssDNAs bind substantially weaker than isosequential ssRNAs and heparin competes with RNA for binding to VP30, indicating that ribose 2'-hydroxyls and electrostatic contacts of the phosphate groups contribute to the formation of VP30:RNA complexes. Our results indicate a rather relaxed RNA binding specificity of filoviral VP30, which largely differs from that of the functionally related Transcription factor of the Paramyxoviridae which binds to ssRNAs as short as 13 nt with a preference for oligo(A) sequences.
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Role of Ebola Virus VP30 in Transcription reinitiation.
Journal of virology, 2008Co-Authors: Miguel J. Martínez, Nadine Biedenkopf, Valentina Volchkova, Nathalie Alazard-Dany, Olivier Reynard, Bettina Hartlieb, Stephan Becker, Viktor VolchkovAbstract:VP30 is a phosphoprotein essential for the initiation of Ebola Virus Transcription. In this work, we have studied the effect of mutations in VP30 phosphorylation sites on the ebolaVirus replication cycle by using a reverse genetics system. We demonstrate that VP30 is involved in reinitiation of gene Transcription and that this activity is affected by mutations at the phosphorylation sites.
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Ebola Virus Transcription activator VP30 is a zinc-binding protein.
Journal of virology, 2003Co-Authors: Jens Modrof, Stephan Becker, Elke MühlbergerAbstract:Ebola Virus VP30 is an essential activator of viral Transcription. In viral particles, VP30 is closely associated with the nucleocapsid complex. A conspicuous structural feature of VP30 is an unconventional zinc-binding Cys(3)-His motif comprising amino acids 68 to 95. By using a colorimetric zinc-binding assay we found that the VP30-specific Cys(3)-His motif stoichiometrically binds zinc ions in a one-to-one relationship. Substitution of the conserved cysteines and the histidine within the motif led to a complete loss of the capacity for zinc binding. Functional analyses revealed that none of the tested mutations of the proposed zinc-coordinating residues influenced binding of VP30 to nucleocapsid-like particles but, concerning its role in activating viral Transcription, all resulted in a protein that was inactive.
Donald H. Gilden - One of the best experts on this subject based on the ideXlab platform.
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Effect of Time Delay after Necropsy on Analysis of Simian Varicella-Zoster Virus Expression in Latently Infected Ganglia of Rhesus Macaques
Journal of Virology, 2010Co-Authors: Ravi Mahalingam, Vicki Traina-dorge, Eileen Deharo, Anjani Golive, Ilhem Messaoudi, Mary Wellish, Donald H. GildenAbstract:Studies of varicella-zoster Virus gene expression during latency require the acquisition of human ganglia at autopsy. Concerns have been raised that the Virus might reactivate immediately after death. Because features of varicella-zoster Virus latency are similar in primate and human ganglia, we examined Virus gene expression in tissues either processed immediately or kept at 4°C for 30 h before necropsy of two monkeys inoculated with simian varicella-zoster Virus and euthanized 117 days later. Virus Transcription and the detection of open reading frame (ORF) 63 protein in the cytoplasm of neurons were comparable. Thus, a 30-h delay after death did not affect varicella-zoster Virus expression in latently infected ganglia.
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Varicella zoster Virus Transcription in latently-infected human ganglia.
Anticancer research, 2003Co-Authors: Randall J. Cohrs, Donald H. GildenAbstract:Varicella zoster Virus (VZV) causes childhood chickenpox, becomes latent in cranial, dorsal root and autonomic ganglia, and can reactivate decades later to cause shingles and other serious neurological complications. Herein, we summarize investigations conducted over the past decade that have identified Virus genes expressed in latently-infected human ganglia. A model of VZVgene regulation during latent infection was tested and future directions in the study of VZV latency are discussed.
Alison J Sinclair - One of the best experts on this subject based on the ideXlab platform.
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epigenetic control of epstein barr Virus Transcription relevance to viral life cycle
Frontiers in Genetics, 2013Co-Authors: Alison J SinclairAbstract:DNA methylation normally leads to silencing of gene expression but Epstein–Barr Virus (EBV) provides an exception to the epigenetic paradigm. DNA methylation is absolutely required for the expression of many viral genes. Although the viral genome is initially un-methylated in newly infected cells, it becomes extensively methylated during the establishment of viral latency. One of the major regulators of EBV gene expression is a viral Transcription factor called Zta (BZLF1, ZEBRA, Z) that resembles the cellular AP1 Transcription factor. Zta recognizes at least 32 variants of a 7-nucleotide DNA sequence element, the Zta-response element (ZRE), some of which contain a CpG motif. Zta only binds to the latter class of ZREs in their DNA-methylated form, whether they occur in viral or cellular promoters and is functionally relevant for the activity of these promoters. The ability of Zta to interpret the differential DNA methylation of the viral genome is paramount for both the establishment of viral latency and the release from latency to initiate viral replication.
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Epigenetic control of Epstein–Barr Virus Transcription – relevance to viral life cycle?
Frontiers in Genetics, 2013Co-Authors: Alison J SinclairAbstract:DNA methylation normally leads to silencing of gene expression but Epstein–Barr Virus (EBV) provides an exception to the epigenetic paradigm. DNA methylation is absolutely required for the expression of many viral genes. Although the viral genome is initially un-methylated in newly infected cells, it becomes extensively methylated during the establishment of viral latency. One of the major regulators of EBV gene expression is a viral Transcription factor called Zta (BZLF1, ZEBRA, Z) that resembles the cellular AP1 Transcription factor. Zta recognizes at least 32 variants of a 7-nucleotide DNA sequence element, the Zta-response element (ZRE), some of which contain a CpG motif. Zta only binds to the latter class of ZREs in their DNA-methylated form, whether they occur in viral or cellular promoters and is functionally relevant for the activity of these promoters. The ability of Zta to interpret the differential DNA methylation of the viral genome is paramount for both the establishment of viral latency and the release from latency to initiate viral replication.
Mitsutaka Kitano - One of the best experts on this subject based on the ideXlab platform.
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synergistic antiviral activity of s 033188 s 033447 a novel inhibitor of influenza Virus cap dependent endonuclease in combination with neuraminidase inhibitors in vitro
Open Forum Infectious Diseases, 2017Co-Authors: Mitsutaka Kitano, Atsuko Yamamoto, Takeshi Noshi, Makoto Kawai, Ryu Yoshida, Akihiko Sato, Takao Shishido, Akira NaitoAbstract:Background S-033447, an active form of orally available prodrug S-033188, is a novel small molecule inhibitor of cap-dependent endonuclease that is essential for influenza Virus Transcription and replication. In this study, we evaluated the inhibitory effect of S-033188 in combination with neuraminidase inhibitors on the replication of influenza A/H1N1 Virus in cultured cells.
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Synergistic Antiviral Activity of S-033188/S-033447, a Novel Inhibitor of Influenza Virus Cap-Dependent Endonuclease, in Combination with Neuraminidase Inhibitors In Vitro.
Open Forum Infectious Diseases, 2017Co-Authors: Mitsutaka Kitano, Atsuko Yamamoto, Takeshi Noshi, Makoto Kawai, Ryu Yoshida, Akihiko Sato, Takao Shishido, Akira NaitoAbstract:Background S-033447, an active form of orally available prodrug S-033188, is a novel small molecule inhibitor of cap-dependent endonuclease that is essential for influenza Virus Transcription and replication. In this study, we evaluated the inhibitory effect of S-033188 in combination with neuraminidase inhibitors on the replication of influenza A/H1N1 Virus in cultured cells.
