Protein kinase C-delta mRNA is down-regulated transcriptionally and post-transcriptionally by 12-O-tetradecanoylphorbol-13-acetate.
Activation of protein kinase C-delta (PKC-delta) by 12-O-tetradecanoylphorbol-13-acetate (TPA) is followed by a gradual decrease in detectable protein 12-24 h later in the mouse B lymphoma cell line A20. Down-regulation is associated with TPA-induced proteolysis and a 50-86% decrease in PKC-delta mRNA 0.5-24 h post-treatment which is due to both a 50% decrease in transcription and accelerated degradation of PKC-delta mRNA as determined using the pulse-chase method. Destabilization of PKC-delta mRNA is also observed when actinomycin D is added to cells pretreated with TPA for 2 h; however, addition of actinomycin D or cycloheximide prior to TPA treatment blocks destabilization. Addition of PKC inhibitors to TPA-treated cells also blocks destabilization of PKC-delta mRNA. Cells treated with TPA for 4 h contain an activity not found in control cells which destabilizes PKC-delta mRNA but not glyceraldehyde-3-phosphate dehydrogenase mRNA in vitro. Addition of TPA to control extracts fails to increase degradation of PKC-delta mRNA in vitro, suggesting that treatment of intact cells is required to induce the synthesis of a factor(s) that destabilizes PKC-delta mRNA. This factor(s) then acts along with transcriptional and post-translational regulatory mechanisms to down-regulate PKC-delta.
Shih
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Molecular and Cellular Biology Program, Arizona State University, Tempe, Arizona 85287-1501, USA.
Floyd-Smith
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D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D015152:Blotting, Northern; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D003609:Dactinomycin / Q000494:pharmacology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007527:Isoenzymes / Q000096:biosynthesis* / Q000378:metabolism; D007700:Kinetics; D016393:Lymphoma, B-Cell; D051379:Mice; D009281:Naphthalenes / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D011493:Protein Kinase C / Q000096:biosynthesis* / Q000378:metabolism; D051745:Protein Kinase C-delta; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured
D000470:Alkaloids; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D009281:Naphthalenes; D010617:Phenanthridines; D012333:RNA, Messenger; D003609:Dactinomycin; C016299:chelerythrine; C497259:Prkcd protein, mouse; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate