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Strain-specific determinants on the major phosphoprotein of murine mammary tumor viruses
Abstract:
The major phosphoprotein (p23) of murine mammary tumor virus (MuMTV) was purified for C3H virus, using a combination of alkyl agarose chromatography and gel filtration. Monospecific antiserum was raised against glutaraldehyde crosslinked polymers of purified p23, and the antiserum was then used with iodinated p23 to develop a competition radioimmunoassay. Phosphoprotein p23 was shown to contain both group- and type-specific antigenic determinants in assays using detergent-disrupted virions of MuMTV strains C3H, RIII, GR, and DBA/2 as competing antigens. Tryptic and chymotryptic peptide mapping analysis of p23 polypeptides isolated from MuMTV strains C3H, RIII, GR and DBA/2 showed that the p23s of each virus strain could be clearly distinguished from each other.
Insights
Murine mammary tumor virus (MuMTV) phosphoprotein p23 contains group- and type-specific antigenic determinants. Peptide mapping revealed distinct differences among p23 proteins from various MuMTV strains, aiding in viral characterization.
Area of Science:
- Virology
- Immunology
- Biochemistry
Background:
- Murine mammary tumor virus (MuMTV) is a retrovirus associated with mammary tumors in mice.
- The major phosphoprotein (p23) is a key viral component whose antigenic properties are crucial for understanding viral diversity and host response.
Purpose of the Study:
- To purify and characterize the major phosphoprotein (p23) of MuMTV.
- To investigate the antigenic determinants of p23 and its variability across different MuMTV strains.
Main Methods:
- Purification of p23 using alkyl agarose chromatography and gel filtration.
- Development of a competition radioimmunoassay using monospecific antiserum against p23.
- Peptide mapping analysis (tryptic and chymotryptic) of p23 from different MuMTV strains.
Main Results:
- Purified p23 was obtained from C3H MuMTV.
- The radioimmunoassay demonstrated that p23 possesses both group- and type-specific antigenic determinants.
- Peptide mapping clearly distinguished the p23 proteins from MuMTV strains C3H, RIII, GR, and DBA/2.
Conclusions:
- MuMTV p23 exhibits antigenic heterogeneity, with both conserved and strain-specific features.
- Peptide mapping provides a sensitive method for differentiating MuMTV strains based on their p23 protein structure.
- These findings contribute to the serological classification and understanding of MuMTV diversity.