Interferon, double-stranded RNA, and protein phosphorylation

Abstract

We reported earlier that the addition of double-stranded RNA and ATP increases the endonuclease activity more in an extract of Ehrlich ascites tumor cells which have been treated with an interferon preparation than in a comparable extract from control cells. We report here that the addition of double-stranded RNA to an extract from Ehrlich ascites tumor cells which have been treated with an interferon preparation [or with the interferon inducer poly(I)-poly(C)] promotes the phosphorylation by [γ-³²P]ATP of at least two proteins: P₁ (molecular weight of 64,000) and P₂ (molecular weight of 37,000). Double-stranded RNA also promotes the phosphorylation of at least one (i.e., P₁) of these two proteins in an extract from cells which have not been treated with interferon, but the extent of phosphorylation is much smaller. Double-stranded RNA which has been degraded by RNase III, or DNA, does not promote the phosphorylation.