title: Muscarinic acetylcholine receptors activate expression of the EGR gene family of transcription factors.
abstract: In order to search for genes that are activated by muscarinic acetylcholine receptors (mAChRs), we used an mRNA differential display approach in HEK293 cells expressing m1AChR. The zinc-finger transcription factor genes Egr-1, Egr-2, and Egr-3 were identified. Northern blot analyses confirmed that mRNA levels of Egr-1, Egr-2, and Egr-3 increased readily after m1AChR stimulation and that a maximum was attained within 50 min. At that time, Egr-4 mRNA was also detectable. Western blots and electromobility shift assays demonstrated synthesis of EGR-1 and EGR-3, as well as binding to DNA recognition sites in response to m1AChR activation. Activation of m1AChR increased transcription from EGR-dependent promoters, including the acetylcholinesterase gene promoter. Activity-dependent regulation of Egr-1 mRNA expression and EGR-1 protein synthesis was also observed in cells expressing m2, m3, or m4AChR subtypes. Increased EGR-1 synthesis was mimicked by phorbol myristate acetate, but not by forskolin, and receptor-stimulated EGR-1 synthesis was partially inhibited by phorbol myristate acetate down-regulation. Together, our results demonstrate that muscarinic receptor signaling activates the EGR transcription factor family and that PKC may be involved in intracellular signaling. The data suggest that transcription of EGR-dependent target genes, including the AChE gene, can be under the control of extracellular and intracellular signals coupled to muscarinic receptors.
authors.affiliation: Center for Molecular Neurobiology and Alzheimer's Disease Research Group, University of Hamburg, Martinistrasse 52, D-20246 Hamburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: von der Kammer
authors.forename: M
authors.initials: M
authors.lastname: Mayhaus
authors.forename: C
authors.initials: C
authors.lastname: Albrecht
authors.forename: J
authors.initials: J
authors.lastname: Enderich
authors.forename: M
authors.initials: M
authors.lastname: Wegner
authors.forename: R M
authors.initials: RM
authors.lastname: Nitsch
mesh_terms: D002460:Cell Line; D005786:Gene Expression Regulation / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D007668:Kidney / Q000196:embryology; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection / Q000235:genetics; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D011976:Receptors, Muscarinic; D014157:Transcription Factors; D013755:Tetradecanoylphorbol Acetate