Related Experiment Videos
Abstract:
We have studied the entry of murine retrovirus into mouse fibroblasts by following the fate of both radioactively (protein) labeled virus particles and infectious virus particles. Physical and infectious particles bound to the cell surface with a half time of 1.5-2 hr. Both types of particles were internalized with a half time of approximately 3 hr as measured by the resistance to externally added proteases. The binding proceeded both at 37 and 0 degrees, whereas the internalization was blocked at 0 degrees. The internalized physical particles followed two routes: they either were degraded or remained stable in the cell. Degradation was blocked by lysosomotropic bases and is therefore believed to occur in the lysosomes. Infection could also be inhibited by lysosomotropic bases when present in the first hours after the internalization, indicating that the infectious route also is leading through the lysosomes or another acidic compartment of the cell.
Insights
Murine retrovirus enters mouse cells by binding and internalization. Viral entry and degradation are acid-dependent, suggesting lysosomes are involved in the retroviral infection process.
Area of Science:
- Virology
- Cell Biology
- Molecular Biology
Background:
- Murine retroviruses are significant pathogens in animal models.
- Understanding viral entry mechanisms is crucial for developing antiviral strategies.
Purpose of the Study:
- To investigate the cellular entry pathway of murine retrovirus into mouse fibroblasts.
- To differentiate between physical particle fate and infectious particle entry.
Main Methods:
- Utilized radioactively labeled and infectious murine retrovirus particles.
- Monitored particle binding and internalization using protease resistance assays.
- Assessed the effect of temperature and lysosomotropic bases on viral entry and fate.
Main Results:
- Both physical and infectious viral particles bound to fibroblasts with a half-time of 1.5-2 hours.
- Internalization occurred with a half-time of approximately 3 hours and was temperature-dependent (blocked at 0°C).
- Internalized particles were either degraded (lysosome-dependent) or remained stable; infection was inhibited by lysosomotropic bases.
Conclusions:
- Murine retrovirus entry involves sequential binding and internalization steps.
- The infectious pathway appears to involve acidic compartments, likely lysosomes, for viral processing and infection.
- Lysosomotropic bases can inhibit retroviral infection by interfering with post-internalization events.