Human interferon-α A/D (BgfII) (IFN-α A/D) and mouse interferon-γ (IFN-γ) are shown to induce xanthine dehydrogenase (XD) mRNA in L929 fibroblastic cells. XD mRNA accumulation after IFN-α A/D treatment is relatively fast. being already evident after 4 h and reaching its maximum alter 24 h. IFN-α A/D is active in inducing XD mRNA at 0.1 unit/ml and it is maximally active at 103 units/ml. The half-life of the XD message is unaffected by IFN-α A/D treatment whereas the transcriptional activity of the XD gene and the concentrations of XD heterogeneous nuclear RNA are increased by 2- and 6-fold respectively. The effect of IFN-α A/D on XD mRNA is insensitive to cycloheximide, suggesting that protein synthesis de novo is not required. Experiments conducted with specific inhibitors suggest that protein kinase C, cyclic AMP and arachidonic acid metabolites derived from lipoxygenase or cycloxygenase do not act as second-messenger molecules in the induction of XD mRNA by IFN-α A/D. XD mRNA is also induced in NIH3T3 fibroblastic cells, but not in F9 teratocarcinoma or B16 melanoma cells after treatment with IFN-α A/D. NIH3T3 are the only cells so far tested that have detectable XD and xanthine oxidase activities under basal conditions and alter IFN-α A/D treatment although their responsiveness to the cytokine is much less than that observed in L929 cells.
|Number of pages||8|
|Publication status||Published - 1992|
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