Posttranscriptional control of human gamma interferon gene expression in transfected mouse fibroblasts.

Human gamma interferon genomic DNA was introduced into NIH 3T3 fibroblasts by calcium phosphate precipitation and was not expressed in these cells at the cytoplasmic mRNA or protein level. Treatment of the transfected cells with cycloheximide (1 microgram/ml) induced the accumulation of cytoplasmic gamma interferon mRNA and biologically active human gamma interferon. Analysis of the nuclear enriched RNA from untreated cells indicated that human gamma interferon mRNA was present, suggesting that cycloheximide may act by inhibiting a specific nuclease or may enhance the processing or transport of the RNA from the nucleus to the cytoplasm.