Characterization of bi-segmented and tri-segmented recombinant Pichinde virus particles.

Area of Science:

• Virology
• Molecular Biology
• Structural Biology

Background:

• Mammarenaviruses, including Lassa virus, are dangerous pathogens causing hemorrhagic fevers with no vaccines or effective treatments.
• Limited knowledge exists on cellular proteins within virions and their role in mammarenavirus infection.
• Pichinde virus (PICV) is a model arenavirus for studying replication and pathogenesis.

Purpose of the Study:

• To investigate the morphology and protein composition of recombinant PICV (rPICV) virions with bi-segmented and tri-segmented RNA genomes.
• To compare the structural differences between bi-segmented and tri-segmented PICV particles.
• To identify cellular proteins associated with PICV virions and explore their potential roles in viral infection.

Main Methods:

• Purification of recombinant PICV (rPICV) virions (bi-segmented and tri-segmented) using density-gradient ultracentrifugation.
• Analysis of virion morphology and size via cryo-electron microscopy.
• Proteomic analysis using mass spectrometry to identify associated cellular proteins.

Main Results:

• Both bi-segmented and tri-segmented rPICV virions exhibited pleomorphic, spherical morphology with no significant size difference.
• Tri-segmented rPICV particles were denser than bi-segmented particles.
• Similar sets of cellular proteins were found in both virion types, including endosomal sorting complex (ESCRT) components (ALIX, Tsg101, VPS, CHMP) involved in budding, and other proteins like chaperones and ribosomal proteins.

Conclusions:

• Recombinant PICV with bi- and tri-segmented genomes display similar morphology but distinct densities.
• Virions are enriched with cellular proteins crucial for virus assembly and budding, offering targets for antiviral strategies.
• Findings advance understanding of mammarenavirus particle formation and inform the development of viral vectors and antiviral therapies.