Nucleic Acid and Proteins Isolated from a Strain of Murine Sarcoma Virus (MSV-0)

Abstract

Summary

Murine sarcoma virus (MSV-0, Moloney) was grown in tissue cultures of transformed rat cells (MSB-1). The virus was harvested from the medium and purified by sucrose density gradient ultracentrifugation. The incorporation of ³H-uridine was shown to be reduced in virus preparation from cells treated with a crude rat interferon preparation, when compared to controls. The viral nucleic acid was extracted and characterized by sucrose density ultracentrifugation. A sedimentation value of 52S or 64S was obtained, depending on the reference values used. Upon heating to 80° the viral RNA dissociated into a major 32S and minor smaller S value species, suggesting that the larger RNA is either an aggregate of smaller 32S units, or that modifications had taken place in the secondary structure of the RNA. Pancreatic ribonuclease treatment disclosed no ribonuclease-resistant RNA in the virus or in the MSB cells. The proteins were extracted from purified MSV (0), solubilized, and separated by polyacrylamide gel electrophoresis. Six proteins were identified.