|
Basic Characteristics of Mutations
|
|
Mutation Site
|
M184V |
|
Mutation Site Sentence
|
The M184V mutation, commonly associated with resistance to NRTIs such as lamivudine and emtricitabine, and the M184V/A114S mutations, both located within the hydrophobic pocket, were shown to reduce Islatravir susceptibility in cell-based viral resistance selection assays. |
|
Mutation Level
|
Amino acid level |
|
Mutation Type
|
Nonsynonymous substitution |
|
Gene/Protein/Region
|
RT |
|
Standardized Encoding Gene
|
gag-pol:155348
|
|
Genotype/Subtype
|
HIV-1 |
|
Viral Reference
|
-
|
|
Functional Impact and Mechanisms
|
|
Disease
|
HIV Infections
|
|
Immune
|
- |
|
Target Gene
|
-
|
|
Clinical and Epidemiological Correlations
|
|
Clinical Information
|
- |
|
Treatment
|
Islatravir |
|
Location
|
- |
|
Literature Information
|
|
PMID
|
40139311
|
|
Title
|
Kinetic Investigation of Resistance to Islatravir Conferred by Mutations in HIV-1 Reverse Transcriptase
|
|
Author
|
Zalenski N,Meredith BR,Savoie DJ,Naas MJ,Suo DJ,Betancourt D,Seay TW,Suo Z
|
|
Journal
|
Journal of molecular biology
|
|
Journal Info
|
2025 Jun 15;437(12):169100
|
|
Abstract
|
Islatravir (EFdA) is a novel nucleoside reverse transcriptase translocation inhibitor (NRTTI) that potently blocks HIV-1 replication in vivo. Its unique structural features in contrast to nucleoside reverse transcriptase inhibitors (NRTIs), particularly the 4'-ethynyl and 3'-hydroxy groups, contribute to its high clinical potency. Once intracellularly activated to EFdA 5'-triphosphate (EFdA-TP), it competes with dATP for incorporation by HIV-1 reverse transcriptase (RT) during HIV-1 genomic replication. The 4'-ethynyl group of incorporated EFdA-MP interacts with a hydrophobic pocket of HIV-1 RT, hindering DNA translocation and terminating DNA synthesis. The M184V mutation, commonly associated with resistance to NRTIs such as lamivudine and emtricitabine, and the M184V/A114S mutations, both located within the hydrophobic pocket, were shown to reduce Islatravir susceptibility in cell-based viral resistance selection assays. To elucidate the mechanisms by which these mutations affect Islatravir inhibition, we employed pre-steady-state kinetics to investigate their impact on EFdA-TP incorporation by HIV-1 RT using both DNA and RNA templates. We found that M184V had a modest effect on EFdA-TP incorporation efficiency, increasing it 2-fold with the DNA template and decreasing it 3-fold with the RNA template. In contrast, M184V/A114S significantly inhibited EFdA-TP incorporation, reducing its incorporation efficiency 5.4-fold with the DNA template and 181-fold with the RNA template. These reductions were primarily attributable to corresponding decreases in EFdA-TP incorporation rate constants of 18-fold and 105-fold, respectively. These results suggest that, unlike FDA-approved NRTIs, the clinical efficacy of Islatravir, may not be substantially compromised by the M184V mutation alone but will be significantly reduced by the M184V/A114S mutations.
|
|
Sequence Data
|
-
|
|
|