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Protein synthesis in Simian virus 40-infected monkey cells
Summary
Simian virus 40 (SV40) structural proteins were analyzed using gel electrophoresis. Analysis revealed two major viral proteins and identified potential virus-induced or genome-coded polypeptides in infected cells.
Area of Science:
- Virology
- Molecular Biology
- Protein Chemistry
Background:
- Simian virus 40 (SV40) is a well-characterized DNA tumor virus.
- Understanding SV40 protein composition is crucial for viral replication and pathogenesis studies.
Purpose of the Study:
- To characterize the protein components of purified SV40 virions.
- To compare virion proteins with polypeptides synthesized in SV40-infected monkey cells.
- To identify potential virus-encoded proteins.
Main Methods:
- Sodium dodecyl sulfate-acrylamide gel electrophoresis (SDS-PAGE) of purified SV40.
- Analysis of protein synthesis in SV40-infected monkey cells using pulse-labeling techniques.
Main Results:
- Purified SV40 virions contain two major proteins (44,000 and 31,000 molecular weight), constituting 83% of viral proteins.
- Twelve minor polypeptides were identified, likely cellular or degradation products.
- SV40 infection leads to synthesis of host-cell proteins (90%) and virion components (10%).
- A small fraction of newly synthesized proteins (0.5%) were neither virion components nor found in uninfected cells, suggesting they are virus-induced or encoded.
Conclusions:
- SV40 virions are primarily composed of two structural proteins.
- Infected cells synthesize host proteins and viral structural proteins.
- The study identified novel polypeptides in infected cells, potentially representing SV40-genome-coded proteins.