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Basic Characteristics of Mutations
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Mutation Site
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L17S |
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Mutation Site Sentence
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In agreement with previous findings (33, 46), the exchange of 6 amino acids in the transmembrane domain (E15A, T16V, L17S, V19A, I25L, and V26L) was sufficient to confer efficient antitetherin activity to SIVcpz EK505 Vpu (Fig. 4B, top). |
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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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Vpu |
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Standardized Encoding Gene
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Vpu
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Genotype/Subtype
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HIV-1 N |
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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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Acquired Immunodeficiency Syndrome
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Immune
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Y |
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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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transmembrane domain |
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Location
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- |
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Literature Information
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PMID
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32665270
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Title
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Convergent Evolution of HLA-C Downmodulation in HIV-1 and HIV-2
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Author
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Hopfensperger K,Richard J,Sturzel CM,Bibollet-Ruche F,Apps R,Leoz M,Plantier JC,Hahn BH,Finzi A,Kirchhoff F,Sauter D
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Journal
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mBio
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Journal Info
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2020 Jul 14;11(4):e00782-20
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Abstract
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HLA-C-mediated antigen presentation induces the killing of human immunodeficiency virus (HIV)-infected CD4(+) T cells by cytotoxic T lymphocytes (CTLs). To evade killing, many HIV-1 group M strains decrease HLA-C surface levels using their accessory protein Vpu. However, some HIV-1 group M isolates lack this activity, possibly to prevent the activation of natural killer (NK) cells. Analyzing diverse primate lentiviruses, we found that Vpu-mediated HLA-C downregulation is not limited to pandemic group M but is also found in HIV-1 groups O and P as well as several simian immunodeficiency viruses (SIVs). We show that Vpu targets HLA-C primarily at the protein level, independently of its ability to suppress NF-kappaB-driven gene expression, and that in some viral lineages, HLA-C downregulation may come at the cost of efficient counteraction of the restriction factor tetherin. Remarkably, HIV-2, which does not carry a vpu gene, uses its accessory protein Vif to decrease HLA-C surface expression. This Vif activity requires intact binding sites for the Cullin5/Elongin ubiquitin ligase complex but is separable from its ability to counteract APOBEC3G. Similar to HIV-1 Vpu, the degree of HIV-2 Vif-mediated HLA-C downregulation varies considerably among different virus isolates. In agreement with opposing selection pressures in vivo, we show that the reduction of HLA-C surface levels by HIV-2 Vif is accompanied by increased NK cell-mediated killing. In summary, our results highlight the complex role of HLA-C in lentiviral infections and demonstrate that HIV-1 and HIV-2 have evolved at least two independent mechanisms to decrease HLA-C levels on infected cells.IMPORTANCE Genome-wide association studies suggest that HLA-C expression is a major determinant of viral load set points and CD4(+) T cell counts in HIV-infected individuals. On the one hand, efficient HLA-C expression enables the killing of infected cells by cytotoxic T lymphocytes (CTLs). On the other hand, HLA-C sends inhibitory signals to natural killer (NK) cells and enhances the infectivity of newly produced HIV particles. HIV-1 group M viruses modulate HLA-C expression using the accessory protein Vpu, possibly to balance CTL- and NK cell-mediated immune responses. Here, we show that the second human immunodeficiency virus, HIV-2, can use its accessory protein Vif to evade HLA-C-mediated restriction. Furthermore, our mutational analyses provide insights into the underlying molecular mechanisms. In summary, our results reveal how the two human AIDS viruses modulate HLA-C, a key component of the antiviral immune response.
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Sequence Data
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KY953207
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