Identification of a polypeptide encoded by the avian sarcoma virus src gene

Area of Science:

• Molecular Biology
• Virology
• Oncogenesis

Background:

• The avian sarcoma virus (ASV) possesses a src gene implicated in cellular transformation.
• Identifying the specific polypeptide encoded by the ASV src gene is crucial for understanding its oncogenic mechanisms.

Purpose of the Study:

• To identify and characterize the protein product of the avian sarcoma virus (ASV) src gene.
• To confirm the identity of the ASV src gene polypeptide using distinct biochemical approaches.

Main Methods:

• Immunoprecipitation of a 60,000 molecular weight (Mr) antigen from ASV-transformed chick embryo fibroblasts using specific antisera.
• In vitro translation of the 3' terminal RNA fragment of the ASV genome in a reticulocyte lysate system.
• Peptide mapping of the synthesized polypeptides using two-dimensional tryptic peptide fractionation.

Main Results:

• A transformation-specific antigen with an Mr of 60,000 was immunoprecipitated from ASV-transformed cells.
• In vitro translation of ASV RNA yielded a polypeptide that co-migrated with the immunoprecipitated antigen.
• Tryptic peptide analysis confirmed the identity of the in vitro translated polypeptide and the immunoprecipitated antigen.

Conclusions:

• The study successfully identified the polypeptide encoded by the ASV src gene.
• The 60,000 Mr polypeptide is confirmed as the transformation-specific antigen produced by the ASV src gene.
• These findings provide direct evidence for the role of the ASV src gene product in viral oncogenesis.