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Microheterogeneity of S-glycoprotein of mouse hepatitis virus temperature-sensitive mutants
E L Oleszak1, K Knisley, L S Rodkey
1Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston 77030.
Abstract:
Mouse hepatitis virus (MHV) strain JHM (MHV-JHM) is a neurotropic coronavirus that causes acute fatal encephalomyelitis in 75-99% of infected mice. The surviving animals may subsequently develop demyelinating disease. We compared the S peplomer protein of the wild type (wt) and five temperature-sensitive (ts) mutants of MHV-JHM. In contrast with the wt, none of these five cause fatal disease (mortality less than 10%). Three of these ts mutants did not induce any demyelinating disease, a fourth caused demyelinating disease in 5% of the animals and a fifth, designated ts8, exhibited strong demyelinating properties and caused demyelination in 99% of the animals. SDS-PAGE analysis revealed no differences in the molecular weight of S peplomer protein of wt or ts MHV-JHM mutants. However, isoelectric focusing of the S protein of these five ts mutants and the wt MHV-JHM, followed by transfer to nitrocellulose sheets and immunoblotting with anti-S specific antibody revealed significant differences in the microheterogeneity of the S protein.
Insights
Mouse hepatitis virus (MHV) strain JHM causes fatal encephalomyelitis and demyelinating disease in mice. Differences in the S peplomer protein
Area of Science:
- Virology
- Neuroscience
- Immunology
Background:
- Mouse hepatitis virus (MHV) strain JHM (MHV-JHM) is a neurotropic coronavirus.
- MHV-JHM causes fatal encephalomyelitis in most infected mice, with survivors potentially developing demyelinating disease.
Purpose of the Study:
- To compare the S peplomer protein of wild-type (wt) MHV-JHM and five temperature-sensitive (ts) mutants.
- To investigate the relationship between S protein characteristics and disease outcomes.
Main Methods:
- Comparison of wt and five ts MHV-JHM mutants.
- Analysis of S peplomer protein using SDS-PAGE and isoelectric focusing.
- Immunoblotting with anti-S specific antibody.
Main Results:
- None of the five ts mutants caused fatal disease, unlike wt MHV-JHM.
- Three ts mutants did not induce demyelination, one caused 5% demyelination, and ts8 caused 99% demyelination.
- SDS-PAGE showed no molecular weight differences in S protein, but isoelectric focusing revealed significant microheterogeneity in the S protein of ts mutants compared to wt.
Conclusions:
- The S peplomer protein's microheterogeneity, not molecular weight, is associated with the varying disease-inducing potentials of MHV-JHM strains.
- Specific alterations in S protein microheterogeneity correlate with the capacity to cause fatal encephalomyelitis and demyelinating disease.