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Cell-free synthesis of polyoma virus capsid proteins VP1 and VP2
Abstract:
Polyadenylated RNA isolated from the cytoplasm of mouse 3T6 cells 28 h after infection with polyoma virus has been isolated and translated in vitro. Polyoma capsid proteins VP1 and VP2 have been identified in the cell-free product by polyacrylamide gel electrophoresis, specific immunoprecipitation, and tryptic peptide fingerprinting. Polyoma mRNA species have been isolated by preparative hybridization to purified viral DNA immobilized on cellulose nitrate filters and shown to code for both VP1 and VP2. These experiments establish conditions for the isolation of late polyoma mRNA and the cell-free synthesis of polyoma capsid proteins and indicate that the active mRNA species are at least partially virus coded.
Insights
Researchers isolated and translated polyoma virus RNA from mouse cells to identify capsid proteins VP1 and VP2. This study establishes methods for isolating late polyoma messenger RNA (mRNA) and synthesizing viral capsid proteins in vitro.
Area of Science:
- Molecular Virology
- Gene Expression and Regulation
- Protein Synthesis
Background:
- Understanding viral protein synthesis is crucial for deciphering viral replication cycles.
- Polyoma virus is a well-characterized DNA tumor virus, making it a model for studying viral gene expression.
Purpose of the Study:
- To isolate and characterize polyoma virus messenger RNA (mRNA) responsible for capsid protein synthesis.
- To establish in vitro conditions for the synthesis of polyoma virus capsid proteins (VP1 and VP2).
Main Methods:
- Isolation of polyadenylated RNA from infected mouse 3T6 cells.
- In vitro translation of isolated RNA.
- Identification of synthesized proteins using polyacrylamide gel electrophoresis, immunoprecipitation, and tryptic peptide fingerprinting.
- Isolation of specific polyoma mRNA species via hybridization to immobilized viral DNA.
Main Results:
- Polyoma virus capsid proteins, VP1 and VP2, were identified in the cell-free translation products.
- Isolated polyoma mRNA species were demonstrated to code for both VP1 and VP2.
- Conditions were established for isolating late polyoma mRNA.
Conclusions:
- The study successfully established conditions for isolating late polyoma mRNA and synthesizing viral capsid proteins in vitro.
- The findings indicate that the active mRNA species coding for VP1 and VP2 are at least partially virus-encoded.