De novo protein synthesis is essential to human interferon gamma gene expression by the stimulation with polyI:polyC.

Transcription of human interferon (IFN) gamma gene is induced in human peripheral lymphocyte nylon-nonadherent cells (NNA cells) by double strand RNA poly I:poly C [(1985) J. Interferon Res. 5, 77-84]. In this report, the necessity of de novo protein synthesis in an early stage of IFN gamma gene expression is described. For induction of IFN gamma gene expression, only initial 4 h treatment of poly I:poly C to NNA cells is sufficient. Addition of inhibitor of protein synthesis, cycloheximide (CHX), at an early stage of induction periods (0-4 h) inhibits the IFN gamma induction by poly I:poly C. Cell free translation assay using RNAs isolated from NNA cells which are induced by poly I:poly C in the presence of CHX reveals that in these RNAs, IFN gamma mRNA does not exist. These results demonstrate that CHX inhibits de novo synthesis of a certain protein (or proteins) and for lack of the protein(s), IFN gamma mRNA cannot be transcribed. The evidence is also described in this report which suggests that the essential protein(s) might be that (those) involved in protein kinase C (pkC) activation.