Post-translational and transcriptional regulation of polyamine biosynthesis in Escherichia coli.
Ornithine and arginine decarboxylases (ODC and ADC) of Escherichia coli are inhibited post-translationally by antizyme and ribosomal proteins S20 and L34. The inhibition of either enzyme is relieved when excess of the other decarboxylase is added. Using this approach, in vitro as well as in vivo, we demonstrate that the extent of the post-translational inhibition of ODC and ADC in E. coli is at least 65 and 50%, respectively. The inhibited enzyme levels increase even further upon exposure of cells to polyamines. The post-translational mode of regulation can counteract a 4-fold increase of ODC protein in the cell. The negative transcriptional regulation of ODC and ADC expression by polyamines is mediated by transcription factors and not by direct polyamine effects on the promoters of their genes. Three proteins interacting with the ODC promoter region were found by southwestern blot analysis.
Panagiotidis
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Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510.
Huang
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Canellakis
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D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism*; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines / Q000378:metabolism / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology; D012269:Ribosomal Proteins / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D011506:Proteins; D012269:Ribosomal Proteins; D014157:Transcription Factors; C031017:ornithine decarboxylase antizyme; C041672:ribosomal protein L34; C029611:ribosomal protein S20; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; C019722:arginine decarboxylase