Different rat-derived transforming retroviruses code for an immunologically related intracellular phosphoprotein

Area of Science:

• Virology
• Molecular Biology
• Oncology

Background:

• Kirsten sarcoma virus (Ki-MSV) and Harvey sarcoma virus (Ha-MSV) are mouse-rat recombinant viruses.
• A phosphoprotein, p21, coded by Ki-MSV and Ha-MSV, has been identified in transformed cells.
• p21 is not a virion structural protein and was identified using specific antisera.

Purpose of the Study:

• To investigate the genetic information and protein products of a purely rat sarcoma virus (RaSV).
• To compare the protein products of RaSV with those of known sarcoma viruses like Ha-MSV and Ki-MSV.
• To determine the role of the RaSV-coded protein in fibroblast transformation.

Main Methods:

• Utilized antisera prepared by transplantation of syngeneic transformed nonproducer cells to identify viral proteins.
• Applied V-8 protease digestion to generate peptides for comparison.
• Examined a temperature-sensitive mutant of Ki-MSV for transformation maintenance.

Main Results:

• Identified a p29 protein coded by RaSV.
• Demonstrated that RaSV's p29 shares immunological determinants and V-8 protease-generated peptides with Ha-MSV's p21.
• Suggested that RaSV acquired genetic information similar to Ki-MSV and Ha-MSV.
• Indicated that the gene coding for p29 is essential for maintaining RaSV-induced fibroblast transformation.

Conclusions:

• RaSV appears to have acquired genetic information with coding capacity similar to that of Ki-MSV and Ha-MSV.
• The p29 protein coded by RaSV plays a critical role in maintaining fibroblast transformation.
• Further research into viral oncogenes and their mechanisms of transformation is warranted.