Regulation of the 202 gene expression by interferons in L929 cells

Type I and II interferons (IFNs) stimulate the expression of the 202 and 2′-5′ oligoadenylate synthetase (OASE) genes in L929, NIH 3T3 and LM-TK^- fibroblastic cell lines. In two other cell lines, B16 melanoma and F9 teratocarcinoma, these cytokines induce OASE but not the 202 mRNA. In L929 cells, IFN-α induces the 202 mRNA at concentrations between 10 and 10³ units/ml. To achieve maximal induction of the 202 mRNA, continous exposure of L929 cells to IFN-α is necessary, whereas 30 minutes of exposure are sufficient to trigger maximal upregulation of the OASE transcript. The induction of the 202 mRNA is the consequence of both transcriptional and post-transcriptional events. Cycloheximide, a known inhibitor of protein synthesis, does not block the induction of 202 mRNA by IFN-α, demonstrating that new protein synthesis is not required for this effect. Protein kinase C, arachidonic acid metabolism via the cycloxygenase or the lipoxygenase pathways and cAMP are not involved as second messengers in the induction of the 202 mRNA by IFN-α in L929 cells.