Polypeptides of avian RNA tumor viruses: V. Analysis of the virus core

Abstract Disruption of avian myeloblastosis virus (AMV) with NP 40 followed by a brief treatment with cold ether led to a quantitative isolation of structures resembling the virus core. Analysis of the cores indicated that they contained the high molecular weight virus RNA, a major polypeptide (28,000 daltons molecular weight) which represents a group-specific (gs) antigen, and RNA and DNA polymerizing activities. Treatment of the cores with various enzymes and examination in the electron microscope indicated that both lipid and protein were required for their integrity. When the core preparations were applied to chick embryo fibroblast cultures, virus particles containing gs antigen and high-molecular-weightRNA were found in the supernatants after two cell passages, indicating the presence of infectious material.