Role of Egr-1 in cholinergic stimulation of phenylethanolamine N-methyltransferase promoter.
The effects of the cholinergic agonist carbachol on phenylethanolamine N-methyltransferase promoter activity and Egr-1 mRNA expression in PC12-derived RS1 cells were examined to investigate the potential involvement of Egr-1 in the neural regulation of phenylethanolamine N-methyltransferase gene expression. Carbachol stimulated luciferase expression in cells transfected with a rat phenylethanolamine N-methyltransferase promoter-luciferase reporter gene construct and also elevated Egr-1 mRNA levels in untransfected cells. Maximum induction of Egr-1 mRNA by carbachol was rapid (0.5 h), whereas by comparison, peak luciferase activity was delayed (6 h). In addition, carbachol stimulation of both luciferase and Egr-1 mRNA expression could be completely inhibited by atropine but not hexamethonium. Furthermore, bethanechol but not nicotine could mimic the effects of carbachol, indicating that carbachol activation was mediated through muscarinic cholinergic receptors. Finally, carbachol failed to stimulate luciferase expression in cells transfected with a mutant construct, in which the Egr-1 binding element in the phenylethanolamine N-methyl-transferase promoter was mutated. These results suggest that carbachol activates the phenylethanolamine N-methyltransferase promotor through stimulation of Egr-1 expression, and are consistent with the potential involvement of Egr-1 in the cholinergic activation of the phenylethanolamine N-methyltransferase gene.
Morita
K
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Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, California 94305-5485, USA.
Wong
D L
DL
D000818:Animals; D018723:Bethanechol / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002999:Clone Cells; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter; D017874:Immediate-Early Proteins; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis; D018721:Muscarinic Agonists / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D016716:PC12 Cells; D010625:Phenylethanolamine N-Methyltransferase / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015347:RNA Probes; D016372:RNA, Antisense; D051381:Rats; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism*; D014162:Transfection; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D018721:Muscarinic Agonists; D018722:Nicotinic Agonists; D015347:RNA Probes; D016372:RNA, Antisense; D014157:Transcription Factors; D018723:Bethanechol; D009538:Nicotine; D002217:Carbachol; D008156:Luciferases; D010625:Phenylethanolamine N-Methyltransferase