A p60 polypeptide in the feline leukemia virus pseudotype of Moloney sarcoma virus with murine leukemia virus p30 antigenic determinants
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Abstract:
A 60,000-dalton polypeptide (p60) has been identified in the feline leukemia virus (FeLV) pseudotype of Moloney sarcoma virus [MSV(FeLV)]. This polypeptide is present in the purified virus complex in concentrations greater than either the murine p30 or the feline p27. Purified p60 crossreacts immunologically with murine p30 group antiserum and contains several interspecies determinants, whereas the group specific determinant of FeLV p27 is not detected. Comparison of peptide fingerprints of p60 and murine p30 show many peptides in common. Limited digestion of p60 with either trypsin or chymotrypsin produced p30-35 and p20 peptides which retain the MuLV p30 group and interspecies antigenic activities. The p30 produced by both enzymes comigrates in polyacrylamide gels with the murine p30 of MSV(FeLV), thus suggesting that p60 may be an uncleaved precursor to p30.
Insights
Researchers identified a 60,000-dalton polypeptide (p60) in Moloney sarcoma virus pseudotyped with feline leukemia virus (FeLV). This p60 appears to be an unprocessed precursor to the murine p30 protein.
Area of Science:
- Retroviral research
- Molecular virology
- Protein characterization
Background:
- Feline leukemia virus (FeLV) pseudotypes of Moloney sarcoma virus [MSV(FeLV)] contain specific viral proteins.
- Understanding the protein composition of MSV(FeLV) is crucial for retroviral studies.
Purpose of the Study:
- To identify and characterize a novel polypeptide (p60) within the MSV(FeLV) complex.
- To investigate the relationship between p60 and known viral proteins like murine p30 and feline p27.
Main Methods:
- Isolation and purification of the MSV(FeLV) virus complex.
- Immunological cross-reactivity assays using murine p30 group antiserum.
- Peptide fingerprinting to compare p60 and murine p30.
- Limited enzymatic digestion (trypsin, chymotrypsin) of p60 followed by gel electrophoresis.
Main Results:
- A 60,000-dalton polypeptide (p60) was identified in purified MSV(FeLV) at high concentrations.
- p60 showed immunological cross-reactivity with murine p30 antiserum and contained interspecies determinants, but lacked FeLV p27 group-specific determinants.
- Peptide mapping revealed significant similarities between p60 and murine p30. Enzymatic digestion of p60 yielded p30-35 fragments that retained immunological activity and comigrated with authentic murine p30.
Conclusions:
- The data strongly suggest that p60 is an unprocessed precursor to the murine p30 protein found in MSV(FeLV).
- This finding contributes to understanding retroviral protein processing and assembly.