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Basic Characteristics of Mutations
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Mutation Site
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K350N |
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Mutation Site Sentence
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The resistant virus has a nonsynonymous mutation K350N in the helicase gene ORF55. |
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Mutation Level
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Amino acid level |
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Mutation Type
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Nonsynonymous substitution |
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Gene/Protein/Region
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ORF55 |
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Standardized Encoding Gene
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ORF55
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Genotype/Subtype
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- |
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Viral Reference
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-
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Functional Impact and Mechanisms
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Disease
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Cell line
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Immune
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- |
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Target Gene
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-
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Clinical and Epidemiological Correlations
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Clinical Information
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- |
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Treatment
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amenamevir |
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Location
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- |
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Literature Information
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PMID
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39569446
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Title
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Single Amino Acid Substitution Within the Helicase of Varicella Zoster Virus Makes It Resistant to Amenamevir
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Author
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Effendi GB,Aoki K,Marini MI,Takamiya R,Ishimaru H,Nishimura M,Mori Y
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Journal
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Journal of medical virology
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Journal Info
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2024 Nov;96(11):e70080
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Abstract
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A helicase-primase inhibitor, amenamevir (ASP2151), is the active pharmaceutical ingredient of a drug for the herpes zoster that is caused by reactivation of varicella-zoster virus (VZV). Here we report a new amenamevir-resistant VZV isolated under the selection pressure of amenamevir. The resistant virus has a nonsynonymous mutation K350N in the helicase gene ORF55. A recombinant virus artificially constructed harboring the ORF55 K350N also acquired amenamevir resistance, and thus the single amino-acid substitution in helicase is revealed to be responsible for the resistance. We observed that the drug-resistant virus and the ORF55 K350N recombinant virus have high resistance to amenamevir, as the EC(50) values in a plaque reduction assay were > 100 muM, while the two viruses remained susceptible to the nucleoside analog drug acyclovir. No defect in viral growth was observed for these resistant viruses in a plaque size assay in human malignant melanoma cells. However, defect in plaque formation was observed from resistant virus in human fetal lung fibroblast cells, showing that the growth of the resistant virus is dependent on the cell type. We observed that the single amino-acid substitution in the helicase induces amenamevir resistance, confirming the importance of the helicase in amenamevir's inhibition of virus growth. Our findings highlight the importance of regulating the clinical use of amenamevir to minimize the risk of the emergence of helicase K350N mutation, especially in the long-term use of amenamevir by immunosuppressed patients.
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Sequence Data
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-
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