Glycoprotein enrichment in Moloney leukemia virus structural proteins released from interferon-treated cells

Interferon treatment of Moloney-leukemia-virus-infected cells (3T3/MLV) leads to the formation of virus particles enriched with viral structural glycoproteins, in addition to the inhibition of virus production. A preferential inhibitory effect on incorporation of RNA and proteins rather than glycoproteins was found in the released virus particles from interferon-treated cells. Enrichment in 70,000- and 45,000-dalton glycoprotein (gP-70, gP-45) in these particles was further demonstrated by polyacrylamide analysis of viral proteins pulse-labeled with [3H]-leucine. Viral glycoproteins released as soluble antigens were also determined. A 40% reduction was found in gP-70 and gP-45 released from interferon-treated cells. Radioimmunoprecipitation of pulse-chase-labeled cellular viral proteins showed no effect of interferon on the formation of viral structural 30,000-, 15,000- to 12,000-dalton proteins, and gP-70 and gP-45 from their respective precursors. The uncoordinate effect of interferon inhibition on viral 30,000-dalton protein and gP-70 is discussed.