Theiler's murine encephalomyelitis virus group includes two distinct genetic subgroups that differ pathologically and...

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Theiler's murine encephalomyelitis virus (TMEV) causes neurological disease.
• Understanding TMEV replication and genetic diversity is crucial for disease control.

Purpose of the Study:

• To investigate the intracellular development and RNA composition of TMEV isolates.
• To differentiate between virulent and less virulent TMEV strains based on molecular characteristics.

Main Methods:

• Electron microscopy to visualize viral structures within infected cells.
• Sucrose gradient centrifugation to analyze viral RNA sedimentation.
• RNase T1 fingerprinting to compare RNA sequences of different TMEV isolates.

Main Results:

• Virulent TMEV (FA strain) formed crystalline arrays in cytoplasm; less virulent strains did not.
• TMEV RNAs are single-stranded with a 35S sedimentation coefficient.
• Significant differences in RNA fingerprints and oligonucleotide composition were observed between virulent and less virulent TMEV subgroups.

Conclusions:

• TMEV isolates exhibit distinct intracellular replication patterns correlating with virulence.
• Genetic analysis of TMEV RNA reveals significant divergence between subgroups.
• These findings suggest TMEV comprises at least two genetically distinct subgroups.