Effect of dexamethasone on the expression of interleukin-2 in a mouse T cell line.
1. The effect of the synthetic glucocorticoid, dexamethasone (dex), on the production of interleukin-2 (IL-2) and IL-2 mRNA was examined in the mouse T cell line, LBRM-33.4A2. 2. Treatment of Concanavalin A (Con A)-stimulated LBRM-33 cells with low concentrations of dex (10nM) inhibited the production of IL-2 activity by approx. 70%, with a corresponding decrease in IL-2 mRNA levels. 3. In contrast, much higher concentrations of dex (up to 10 microM) inhibited the level of another Con A-inducible mRNA, c-myc mRNA, by only 30%, and did not affect beta-tubulin mRNA levels at all. 4. Thus it appears that inhibition by dex in stimulated LBRM-33 cells is specific for the expression of IL-2 mRNA. 5. Experiments with actinomycin D suggest that dex does not mediate its suppression of IL-2 mRNA accumulation by decreasing the stability of this message; rather, it appears that dex inhibits transcription of the IL-2 gene.
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Department of Genetics and Cell Biology, Washington State University, Pullman 99164.
Magnuson
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Reeves
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D000818:Animals; D015152:Blotting, Northern; D003208:Concanavalin A / Q000494:pharmacology; D015342:DNA Probes; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006207:Half-Life; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014404:Tubulin / Q000235:genetics; D014407:Tumor Cells, Cultured; D014529:Uridine / Q000378:metabolism
D015342:DNA Probes; D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D014404:Tubulin; D003208:Concanavalin A; D003609:Dactinomycin; D003907:Dexamethasone; D013936:Thymidine; D014529:Uridine