Plant Lectin, MoMo30, Pressures HIV-1 to Select for Variants with Deleted N-Linked Glycosylation Sites

TL;DR

A plant protein from Momordica balsamina causes HIV-1 to develop harmful mutations, reducing its ability to infect cells.

Contribution

The study shows that MoMo30 induces deletions in N-linked glycosylation sites on HIV-1, reducing its infectivity.

Findings

MoMo30-treated HIV-1 had 32% fewer N-linked glycosylation sites compared to controls.

Treated virus showed a sixfold reduction in infectivity.

Mutations included missense, nonsense, and frameshift changes in the viral envelope.

Abstract

Momordica balsamina, a plant traditionally used in African medicine, contains a 30 kDa protein, MoMo30, previously identified by our group as an anti-HIV agent that binds glycan residues on the gp120 envelope protein, thereby acting as an entry inhibitor. In this study, we investigated whether prolonged exposure to MoMo30 exerts selective pressure on HIV-1 and induces mutations in the viral envelope (env) gene. T-lymphocyte cells were infected with HIV-1NL4-3 and continuously treated with MoMo30 over a 24-day period. Viral RNA was isolated at regular intervals, and env genes were sequenced using the Illumina platform. RNA sequence variant calling was performed using iVar, which uses a frequency-based binomial test with a default allele frequency threshold of 3% and a minimum base quality of 20 and applies Bonferroni correction for multiple testing. The infectivity of the MoMo30-exposed virus was assessed using MAGI-CXCR4 cells, visualized by β-galactosidase staining, and compared to untreated controls. Statistical significance was determined via two-way ANOVA. MoMo30-treated HIV-1 exhibited multiple detrimental mutations in gp120 and gp41, including missense, nonsense, and frameshift changes. Notably, 32% of N-linked glycosylation sites were deleted in the treated virus, while no such changes were observed in controls. Functionally, the MoMo30-treated virus demonstrated a sixfold reduction in infectivity compared to untreated HIV-1NL4-3. These findings suggest that MoMo30 imposes genetic pressure on HIV-1NL4-3, selecting for mutations that reduce viral fitness.

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