Isolation of subviral components from transmissible gastroenteritis virus

Area of Science:

• Veterinary Virology
• Molecular Virology
• Structural Biology

Background:

• Transmissible gastroenteritis virus (TGEV) is a significant porcine coronavirus causing severe enteric disease.
• Understanding TGEV structure is crucial for developing effective antiviral strategies and vaccines.

Purpose of the Study:

• To characterize the subviral particles and surface proteins of purified TGEV.
• To identify the major structural proteins associated with TGEV RNA and its envelope.

Main Methods:

• Treatment of purified TGEV with non-ionic detergents to remove lipid envelope and surface projections.
• Isolation and characterization of subviral particles using ultracentrifugation and Cs2SO4 density gradients.
• Electron microscopy for visualizing subviral particle morphology.
• Polyacrylamide gel electrophoresis (PAGE) for polypeptide analysis.
• Isolation of surface projections (VPI) via rate-zonal centrifugation.

Main Results:

• Detergent treatment removed >98% of TGEV lipid and surface projections, yielding subviral particles (650S, banding at 1.295 g/ml).
• Subviral particles contained spherical structures (60-70 nm) and three major viral proteins: VP2 (arginine-rich) and two membrane glycopolypeptides (VP2 and VP4).
• Detergent-liberated surface projections (VPI) were identified as a single species of sulphated glycopolypeptide.

Conclusions:

• The study successfully isolated and characterized TGEV subviral particles and its major structural proteins.
• These findings provide insights into the molecular architecture of TGEV, essential for future research and control measures.
• Identification of specific viral proteins (VP2, VP4, VPI) aids in understanding TGEV assembly and pathogenesis.