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Basic Characteristics of Mutations
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Mutation Site
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N298Y |
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Mutation Site Sentence
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Three identical aminoacid substitutions (N297K, N298Y and I318T, relative to the LAI env sequence) were identified in the V3 loop. |
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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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Env |
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Standardized Encoding Gene
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Env
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Genotype/Subtype
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HIV-1 B |
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Viral Reference
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"HLA-C insensitive isolate NDK (clade D);the HLA-C sensitive Envs tested (93MW965, 91US005, 92UG024, ADA, LAI, 6535.3 and pRHPA4259.7)"
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Functional Impact and Mechanisms
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Disease
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HIV Infections
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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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18673537
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Title
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HLA-C increases HIV-1 infectivity and is associated with gp120
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Author
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Matucci A,Rossolillo P,Baroni M,Siccardi AG,Beretta A,Zipeto D
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Journal
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Retrovirology
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Journal Info
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2008 Aug 1;5:68
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Abstract
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BACKGROUND: A recently identified genetic polymorphism located in the 5' region of the HLA-C gene is associated with individual variations in HIV-1 viral load and with differences in HLA-C expression levels. HLA-C has the potential to restrict HIV-1 by presenting epitopes to cytotoxic T cells but it is also a potent inhibitor of NK cells. In addition, HLA-C molecules incorporated within the HIV-1 envelope have been shown to bind to the envelope glycoprotein gp120 and enhance viral infectivity. We investigated this last property in cell fusion assays where the expression of HLA-C was silenced by small interfering RNA sequences. Syncytia formation was analyzed by co-cultivating cell lines expressing HIV-1 gp120/gp41 from different laboratory and primary isolates with target cells expressing different HIV-1 co-receptors. Virus infectivity was analyzed using pseudoviruses. Molecular complexes generated during cell fusion (fusion complexes) were purified and analyzed for their HLA-C content. RESULTS: HLA-C positive cells co-expressing HIV-1 gp120/gp41 fused more rapidly and produced larger syncytia than HLA-C negative cells. Transient transfection of gp120/gp41 from different primary isolates in HLA-C positive cells resulted in a significant cell fusion increase. Fusion efficiency was reduced in HLA-C silenced cells compared to non-silenced cells when co-cultivated with different target cell lines expressing HIV-1 co-receptors. Similarly, pseudoviruses produced from HLA-C silenced cells were significantly less infectious. HLA-C was co-purified with gp120 from cells before and after fusion and was associated with the fusion complex. CONCLUSION: Virionic HLA-C molecules associate to Env and increase the infectivity of both R5 and X4 viruses. Genetic polymorphisms associated to variations in HLA-C expression levels may therefore influence the individual viral set point not only by means of a regulation of the virus-specific immune response but also via a direct effect on the virus replicative capacity. These findings have implications for the understanding of the HIV-1 entry mechanism and of the role of Env conformational modifications induced by virion-associated host proteins.
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Sequence Data
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-
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