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Basic Characteristics of Mutations
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Mutation Site
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N118T |
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Mutation Site Sentence
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The V44G, A66T, R87G, N118T and I127V amino acid mutations were the most prevalent and were identified in 66 (38.2%), 44 (25.4%), 56 (32.4%), 50 (28.9%), and 56 (32.4%) respectively, of the 173 patients. |
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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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X |
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Standardized Encoding Gene
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X
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Genotype/Subtype
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B;C |
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Viral Reference
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NC_003977.2
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Functional Impact and Mechanisms
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Disease
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Hepatitis B, Chronic
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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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Y |
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Treatment
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- |
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Location
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China |
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Literature Information
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PMID
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35762289
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Title
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Hepatitis B virus X gene impacts on the innate immunity and immune-tolerant phase in chronic hepatitis B virus infection
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Author
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Chang KC,Chua HH,Chen YH,Tsuei DJ,Lee MH,Chiang CL,Jeng YM,Wu JF,Chen HL,Hsu HY,Ni YH,Chang MH
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Journal
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Liver international : official journal of the International Association for the Study of the Liver
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Journal Info
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2022 Oct;42(10):2154-2166
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Abstract
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BACKGROUND AND AIMS: The immunologic features involved in the immune-tolerant phase of chronic hepatitis B (CHB) virus (HBV) infection are unclear. The hepatitis B virus X (HBx) protein disrupts IFN-beta induction by downregulating MAVS and may destroy subsequent HBV-specific adaptive immunity. We aimed to analyse the impacts of genetic variability of HBx in CHB patients on the immune-tolerant phase during long-term follow-up. METHODS: Children with CHB in the immune-tolerant phase were recruited and followed longitudinally. HBx gene sequencing of infecting HBV strains was performed, and the effects of HBx mutations on the immune-tolerant phase were assessed. Restoration of the host immune response to end the immune-tolerant phase was investigated by immunoblotting, immunostaining, ELISA and reporter assays of MAVS/IFN-beta signalling in liver cell lines, patient liver tissues and the HBV plasmid replication system. RESULTS: A total of 173 children (median age, 6.92 years) were recruited. Patients carrying HBx R87G, I127V and R87G + I127V double mutations exhibited higher cumulative incidences of immune-tolerant phase breakthrough (p = .011, p = .006 and p = .017 respectively). Cells transfected with HBx R87G and I127V mutants and pHBV1.3-B6.3 replicons containing the HBx R87G and I127V mutations exhibited statistically increased levels of IFN-beta, especially under poly(I:C) stimulation or Flag-MAVS cotransfection. HA-HBx wild-type interacted with Flag-MAVS and enhanced its ubiquitination, but this ability was diminished in the R87G and I127V mutants. CONCLUSIONS: HBx suppresses IFN-beta induction. R87G and I127V mutation restored IFN-beta production by preventing MAVS degradation, contributing to curtailing the HBV immune-tolerant phase in CHB patients.
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Sequence Data
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-
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