|
Basic Characteristics of Mutations
|
|
Mutation Site
|
L146F |
|
Mutation Site Sentence
|
Nef sequence analysis identified two specific amino acid changes (I123L and L146F) that specifically disrupted the CD3 down-modulation activity. |
|
Mutation Level
|
Amino acid level |
|
Mutation Type
|
Nonsynonymous substitution |
|
Gene/Protein/Region
|
Nef |
|
Standardized Encoding Gene
|
Nef
|
|
Genotype/Subtype
|
HIV-1 |
|
Viral Reference
|
-
|
|
Functional Impact and Mechanisms
|
|
Disease
|
HIV Infections
|
|
Immune
|
- |
|
Target Gene
|
-
|
|
Clinical and Epidemiological Correlations
|
|
Clinical Information
|
- |
|
Treatment
|
Nef |
|
Location
|
UK |
|
Literature Information
|
|
PMID
|
32179688
|
|
Title
|
Loss of Nef-mediated CD3 down-regulation in the HIV-1 lineage increases viral infectivity and spread
|
|
Author
|
Mesner D,Hotter D,Kirchhoff F,Jolly C
|
|
Journal
|
Proceedings of the National Academy of Sciences of the United States of America
|
|
Journal Info
|
2020 Mar 31;117(13):7382-7391
|
|
Abstract
|
Nef is an accessory protein of primate lentiviruses that is essential for efficient replication and pathogenesis of HIV-1. A conserved feature of Nef proteins from different lentiviral lineages is the ability to modulate host protein trafficking and down-regulate a number of cell surface receptors to enhance replication and promote immune evasion. Notably, the inability of Nef to down-regulate CD3 from infected T cells distinguishes HIV-1 Nef and its direct simian precursors from other primate lentiviruses. Why HIV-1 does not employ this potential immune evasion strategy is not fully understood. Using chimeric HIV-1 constructs expressing lentiviral Nef proteins that differ in their ability to down-modulate CD3, we show that retaining CD3 on the surface of infected primary T cells results in increased viral replication and cell-to-cell spread. We identified increased expression of envelope (Env) trimers at the cell surface and increased Env incorporation into virions as the determinants for the Nef- and CD3-dependent enhancement of viral infectivity. Importantly, this was independent of Nef-mediated antagonism of the host restriction factor SERINC5. CD3 retention on the surface of infected primary T cells also correlated with increased T cell signaling, activation, and cell death during cell-to-cell spread. Taken together, our results show that loss of an otherwise conserved function of Nef has a positive effect on HIV-1 replication, allowing for more efficient replication while potentially contributing to HIV-1 pathogenesis by triggering T cell activation and cell death during viral spread.
|
|
Sequence Data
|
-
|