Heterogeneity of poly(I).poly(C)-induced human fibroblast interferon mRNA species

Abstract
Since it is generally considered that fibroblast (F) IFN (interferon) represents a single protein, current efforts to clone human F IFN mRNA sequences are based on the observation that F IFN mRNA sediments in sucrose gradients as a single RNA species of size corresponding to 12-14 S. However, gel electrophoresis of mRNA from human fibroblast FS-4 cells exposed to poly(I.cntdot.C) and cycloheximide showed that 2 populations of translationally active human F IFN mRNA molecules exist.sbd.an abundant 14 S species and a scarce 11 S species. Microinjection of either species of mRNA into Xenopus oocytes led to the synthesis of biologically active F-type human IFN.