La generación de una variante resistente a la neutralización del VIH-1 se debe a la selección de una mutación puntual en el gen del sobre
Video Experimental Relacionado
Updated: Jul 31, 2026
14:23
A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses
Published on: August 31, 2014
M S Reitz1, C Wilson, C Naugle
1Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, Maryland 20892.
Cell
|July 1, 1988
Resumen
Las variantes del VIH-1 resistentes a los anticuerpos neutralizantes pueden surgir rápidamente. Un solo cambio de aminoácido en la proteína envolvente puede conferir resistencia, destacando la evolución viral impulsada por el sistema inmunológico.
Área de la Ciencia:
- Virología Virología.
- Inmunología Inmunología.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La proteína de la envoltura del virus de la inmunodeficiencia humana tipo 1 (VIH-1) es un objetivo clave para neutralizar los anticuerpos.
- La evolución viral bajo presión inmune puede conducir a la aparición de cepas resistentes a los fármacos o a la neutralización.
Objetivo del estudio:
- Para investigar la base genética de la resistencia a la neutralización del VIH-1.
- Para determinar si mutaciones específicas en el gen de la envoltura confieren resistencia al antisuero neutralizante.
Principales métodos:
- La generación de variantes del VIH-1 en presencia de antisuero neutralizante.
- Aislar y secuenciar clones moleculares de variantes resistentes.
- La construcción de virus recombinantes con mutaciones genéticas específicas de la envoltura.
- Evaluación de la sensibilidad a la neutralización de los virus de tipo salvaje y recombinantes.
Principales resultados:
- Se generaron variantes del VIH-1 resistentes a un antisuero neutralizante específico.
- Los clones moleculares (MX-1, MX-2) de variantes resistentes contenían mutaciones en el gen del sobre.
- Los virus recombinantes con segmentos de genes de la envoltura intercambiados de clones resistentes también fueron resistentes.
- Una sola sustitución de aminoácidos (Ala a Thr en la posición 582) en la proteína del sobre confirió el fenotipo resistente.
Conclusiones:
- Pequeños cambios genéticos en la proteína envolvente del VIH-1 pueden conducir a una resistencia significativa a la neutralización.
- Las respuestas inmunes in vivo del huésped pueden seleccionar rápidamente variantes virales con susceptibilidad alterada a la neutralización.
- Comprender estos mecanismos es crucial para desarrollar vacunas y terapias efectivas contra el VIH-1.
Videos de Conceptos Relacionados
01:10Retrovirus Life Cycles
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
00:57Viral Recombination
Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.
00:36Viral Mutations
A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material for adaptive...
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
01:26Size and Structure of Viral Genomes
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
01:19Inhibitors of Virion Maturation and Assembly
As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...