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Mutational analysis of the feline immunodeficiency virus matrix protein
M L Manrique1, C C Celma, S A González
1Centro de Virología Animal (CEVAN-CONICET), Serrano 669, C1414DEM, Buenos Aires, Argentina.
Abstract:
To study the process of feline immunodeficiency virus (FIV) assembly, we examined the suitability of the vaccinia vector system to reproduce FIV particle formation. To this end, we constructed a recombinant vaccinia virus carrying the FIV gag gene. Biochemical and electron microscopy analyses of cells infected with this recombinant virus showed that the FIV Gag polyprotein self-assembled into lentivirus-like particles that were released into the culture medium. As a first step in the identification of molecular determinants in FIV Gag that are involved in virus assembly, we performed a site-directed mutagenesis analysis of the N-terminal matrix (MA) domain of the FIV Gag precursor. To this end, a series of amino acid substitutions and small in-frame deletions were introduced into the FIV MA and the mutated FIV gag gene constructs were expressed by means of the vaccinia system. Characterization of the assembly phenotype of these FIV Gag mutants led to the identification of amino acidic regions within the MA domain that are necessary for efficient transport of the Gag precursor to the plasma membrane and particle assembly. Our results reveal the role that the FIV MA plays in virus morphogenesis and contribute to the understanding of the assembly process in non-primate lentiviruses.
Insights
Researchers used a vaccinia virus system to study feline immunodeficiency virus (FIV) assembly. They found the FIV Gag polyprotein self-assembles into virus-like particles, identifying key regions in the matrix (MA) domain essential for particle formation and transport.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Feline immunodeficiency virus (FIV) is a lentivirus that infects cats.
- Understanding FIV assembly is crucial for developing antiviral strategies.
- The FIV Gag polyprotein plays a central role in virus particle formation.
Purpose of the Study:
- To investigate the suitability of the vaccinia virus vector system for studying FIV assembly.
- To identify molecular determinants within the FIV Gag precursor involved in virus assembly.
- To elucidate the role of the FIV matrix (MA) domain in viral morphogenesis.
Main Methods:
- Construction of a recombinant vaccinia virus expressing the FIV gag gene.
- Biochemical and electron microscopy analyses of infected cells.
- Site-directed mutagenesis of the FIV MA domain and analysis of mutant phenotypes.
Main Results:
- The vaccinia system successfully reproduced FIV particle formation, with FIV Gag polyprotein self-assembling into lentivirus-like particles.
- Mutagenesis identified specific amino acid regions within the FIV MA domain essential for Gag transport to the plasma membrane.
- These MA regions are critical for efficient FIV particle assembly.
Conclusions:
- The vaccinia vector system is a suitable tool for studying FIV assembly.
- The FIV MA domain plays a critical role in FIV morphogenesis and virus assembly.
- This study enhances the understanding of lentivirus assembly in non-primate species.