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Basic Characteristics of Mutations
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Mutation Site
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G145A |
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Mutation Site Sentence
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Site-directed mutagenesis was then utilized to introduce three genotype A mutations - M103I, K122R and G145A - associated with Occult hepatitis B in vivo, alone and in combination, into the wild-type HBsAg vectors. |
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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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S |
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Standardized Encoding Gene
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S
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Genotype/Subtype
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A |
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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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Hepatitis B Virus Infection
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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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- |
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Location
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- |
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Literature Information
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PMID
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22967103
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Title
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Mutations associated with occult hepatitis B virus infection result in decreased surface antigen expression in vitro
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Author
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Martin CM,Welge JA,Rouster SD,Shata MT,Sherman KE,Blackard JT
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Journal
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Journal of viral hepatitis
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Journal Info
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2012 Oct;19(10):716-23
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Abstract
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Occult hepatitis B virus (HBV) infection is characterized by the absence of detectable hepatitis B surface antigen (HBsAg) in the serum, despite detectable HBV DNA. Investigations of the mechanisms underlying the development of occult HBV infection are lacking in the current literature, although viral mutations in the surface region, resulting in decreased HBsAg expression or secretion, represent one potential mechanism. Wild-type HBsAg expression vectors were constructed from genotype-matched chronic HBV sequences. Site-directed mutagenesis was then utilized to introduce three genotype A mutations - M103I, K122R and G145A - associated with occult HBV infection in vivo, alone and in combination, into the wild-type HBsAg vectors. Transfection of Huh7 and HepG2 cell lines was performed, and cell culture supernatants and cell lysates were collected over 7 days to assess the effects of these mutations on extracellular and intracellular HBsAg levels. The G145A mutation resulted in significantly decreased extracellular and intracellular HBsAg expression in vitro. The most pronounced reduction in HBsAg expression was observed when all three mutations were present. The mutations evaluated in vitro in the current study resulted in decreased HBsAg expression and potentially increased hepatic retention and/or decreased hepatic secretion of synthesized HBsAg, which could explain the lack of HBsAg detection that is characteristic of occult HBV infection in vivo.
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Sequence Data
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-
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