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Membrane fusion as a mechanism of simian virus 40 entry into different cellular compartments
Abstract:
Permissive and nonpermissive simian virus 40 (SV40)-infected cells were ultrastructurally analyzed. Viral particles were found in the cytoplasm, rough endoplasmic reticulum, nuclear envelope, lysosomes, and mitochondria. Upon entering the cell the virion obtains a tight membrane envelope. It seems to be either released from the envelope upon fusion with other membranes of the cell or aggregated into tubular membrane specializations upon fusion with other membrane-enveloped particles. Reconstructed morphological sequences and the finding of SV40 in different spaces of the cell suggest that entry of SV40 into the different compartments and eventually into the site of replication is facilitated by its capacity for being enveloped by a variety of membranes (notably the cell membrane and the nuclear membrane) and the sequential fusion and fission of these membranes.
Insights
Simian virus 40 (SV40) enters cells by acquiring a membrane envelope, then fusing with cellular membranes. This viral entry mechanism facilitates replication within various cellular compartments.
Area of Science:
- Virology
- Cell Biology
- Microscopy
Background:
- Simian virus 40 (SV40) is a well-characterized DNA tumor virus.
- Understanding viral entry mechanisms is crucial for developing antiviral strategies.
Purpose of the Study:
- To ultrastructurally analyze permissive and nonpermissive SV40-infected cells.
- To elucidate the entry pathway of SV40 into host cells.
Main Methods:
- Ultrastructural analysis of SV40-infected cells using electron microscopy.
- Reconstruction of morphological sequences of viral entry.
Main Results:
- SV40 viral particles were observed in various cellular compartments including cytoplasm, ER, nuclear envelope, lysosomes, and mitochondria.
- Upon entry, SV40 virions acquire a membrane envelope.
- Viral entry appears to be facilitated by membrane fusion and fission events, allowing SV40 to access different cellular compartments.
Conclusions:
- SV40 entry into host cells is a dynamic process involving membrane envelopment and sequential fusion/fission.
- The virus's ability to interact with diverse cellular membranes facilitates its transport to replication sites.