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Comparison of structural and nonstructural proteins of virulent and less virulent Theiler's virus isolates using
Abstract:
The Theiler's murine encephalomyelitis viruses (TMEV) are important neurotropic picornaviruses because they persist in the central nervous system (CNS) and produce an inflammatory demyelinating disease in the mouse, their natural host. Insight into the pathogenesis of this disease may come from studying the genetic and biochemical compositions of these viruses; therefore, in this report, the structural and nonstructural proteins specified by both highly and less virulent TMEV were examined. Using two-dimensional gel electrophoresis, structural and nonstructural proteins, originating from each of the three regions of the picornavirus genome (Kitamura et al., 1981; Rueckert and Wimmer, 1984), from nine TMEV isolates were compared on the basis of isoelectric points (pI). Proteins of two virulent TMEV (GDVII and FA viruses) had almost indistinguishable pI values, whereas two of the three major capsid proteins of the less virulent TMEV varied considerably. For example, the structural proteins VP1 and VP3 from seven less virulent viruses ranged from pI 6.3 to 6.9 and 6.5 to 8.3, respectively. On the other hand, the pI values of VP2 and nonstructural proteins from the less virulent TMEV varied relatively little. In general, structural proteins of each TMEV group had pI ranges unique to their respective biological group, while most nonstructural proteins were similar for all TMEV. The virus-specified proteins of Vilyuisk virus, which is serologically related to the TMEV and a possible cause of encephalomyelitis in man, had pI values similar to the less virulent TMEV. Finally, VP3 not only showed the greatest variation in pI among the less virulent TMEV, but it also was preferentially radioiodinated in intact virus from each of the two biological groups using the lactoperoxidase technique.
Insights
Theiler
Area of Science:
- Neurovirology
- Molecular Biology
- Immunology
Background:
- Theiler's murine encephalomyelitis viruses (TMEV) are neurotropic picornaviruses causing persistent CNS infections and inflammatory demyelinating disease in mice.
- Understanding TMEV pathogenesis is crucial for developing therapeutic strategies against viral-induced neurological disorders.
Purpose of the Study:
- To investigate the genetic and biochemical differences in structural and nonstructural proteins between highly and less virulent TMEV isolates.
- To correlate protein variations with viral virulence and disease pathogenesis.
Main Methods:
- Two-dimensional gel electrophoresis was employed to compare viral proteins based on isoelectric points (pI).
- Nine TMEV isolates were analyzed, focusing on proteins from different genomic regions.
- Radioiodination techniques were used to identify specific viral proteins.
Main Results:
- Highly virulent TMEV (GDVII, FA) exhibited similar protein pI values.
- Less virulent TMEV showed considerable variation in major capsid proteins VP1 and VP3.
- Structural proteins displayed unique pI ranges for each virulence group, while nonstructural proteins were generally conserved.
- Vilyuisk virus proteins were similar to less virulent TMEV.
- VP3 demonstrated the most variation among less virulent strains and was preferentially radioiodinated.
Conclusions:
- Viral protein profiles, particularly capsid proteins like VP3, can distinguish between virulent and less virulent TMEV strains.
- These protein variations may play a role in the differential pathogenesis of TMEV-induced neurological disease.
- Further research into TMEV protein structure-function relationships is warranted.