Characterization of a Sinbis virus variant with altered host range

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Sindbis virus infectivity varies between strains.
• Understanding viral surface properties is key to infectivity.

Purpose of the Study:

• To investigate the biochemical basis for enhanced Sindbis virus infectivity in mouse cells.
• To identify specific viral properties responsible for increased adsorption and infectivity.

Main Methods:

• Comparative analysis of Sindbis virus variant and standard strains.
• Cell adsorption assays using mouse plasmacytoma cells (MOPC 315).
• Heparin pretreatment of cells to assess charge-dependent interactions.
• Biochemical characterization: hydroxyapatite elution and isoelectric focusing of viral glycoproteins.
• Analysis of viral stability to heat and proteolytic enzymes.

Main Results:

• The Sindbis virus variant exhibited significantly enhanced adsorption to MOPC 315 cells compared to the standard strain.
• Heparin pretreatment of cells reduced the adsorption difference, indicating a role for surface charge.
• Isoelectric focusing revealed that both E1 and E2 glycoproteins of the variant were more negatively charged than those of the standard virus.
• The variant showed altered stability to heat and proteolytic enzymes compared to the standard virus.
• No significant changes were observed in the tryptic peptides of the variant's glycoproteins.

Conclusions:

• Enhanced infectivity of the Sindbis virus variant is attributed to increased adsorption, mediated by more negatively charged E1 and E2 glycoproteins.
• Surface charge differences in viral glycoproteins play a crucial role in Sindbis virus-host cell interactions and infectivity.
• The variant's altered stability suggests further biochemical modifications contributing to its biological properties.