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Measles virus-specified polypeptides in infected cells
Abstract:
The synthesis of wild-type measles virus-specified polypeptides in Vero cells in pulse-chase experiments, in cells with synchronized protein synthesis by high salt concentration, and in the presence of proteolytic enzyme inhibitors was analyzed by polyacrylamide slab-gel electrophoresis. Six major (L, G, 2, NP, 5 and M) structural polypeptides were identified in infected cells. The results of pulse-chase experiments suggested that most of the structural polypeptides were synthesized at their final length. Polypeptide M was found to be sensitive to trypsin. In TLCK-treated cells its molecular weight was about 1000--2000 daltons higher than in untreated cells. A minor virus-specific polypeptide with a molecular weight of about 23,000 was found as a very faint and diffuse band. In addition, three nonstructural polypeptides with molecular weights of 65,000, 38,000 and 18,000 were also detected. The experiments with proteolytic enzyme inhibitors and with synchronized protein synthesis suggested that the polypeptide with a molecular weight of 65,000 might be a precursor of the structural polypeptide 5.
Insights
This study identifies six major structural polypeptides in measles virus-infected cells, revealing most are synthesized at their final length. A 65,000-dalton nonstructural polypeptide may be a precursor to structural polypeptide 5.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Measles virus (MeV) is a significant human pathogen.
- Understanding MeV protein synthesis is crucial for antiviral strategies.
Purpose of the Study:
- To analyze the synthesis of wild-type measles virus-specified polypeptides.
- To identify structural and nonstructural viral proteins and their precursors.
Main Methods:
- Polyacrylamide slab-gel electrophoresis was used to analyze viral polypeptides.
- Experiments included pulse-chase, synchronized protein synthesis, and proteolytic enzyme inhibitors.
- Vero cells were used as the host system.
Main Results:
- Six major structural polypeptides (L, G, 2, NP, 5, M) were identified.
- Most structural polypeptides were synthesized at their final length.
- A 65,000-dalton nonstructural polypeptide may be a precursor to structural polypeptide 5.
Conclusions:
- The study characterizes the synthesis and potential precursor-product relationships of measles virus polypeptides.
- Polypeptide M exhibits sensitivity to trypsin, with altered molecular weight in TLCK-treated cells.