Premium
AP1‐Mediated Transcriptional Enhancement of the Rat Tyrosine Hydroxylase Gene by Muscarinic Stimulation
Author(s) -
Chae HeeDon,
Suh ByungChang,
Joh Tong H.,
Kim KyongTai
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66031264.x
Subject(s) - carbachol , muscarinic acetylcholine receptor , protein kinase c , microbiology and biotechnology , biology , endocrinology , chemistry , medicine , stimulation , signal transduction , receptor , biochemistry
We investigated transcriptional regulation of the rat tyrosine hydroxylase (TH) gene by muscarinic stimulation in human neuroblastoma SK‐N‐BE(2)M17 cells. Carbachol treatment increased the levels of intracellular Ca 2+ and inositol 1,4,5‐trisphosphate (IP 3 ) and enhanced transcription of the TH gene. The muscarinic receptor antagonist atropine completely abolished the carbachol effect on TH gene expression. When cells were loaded with 50 µ M 1,2‐bis(2‐aminophenoxy)ethane‐ N,N,N′,N′ ‐tetraacetic acid/acetoxymethyl ester (BAPTA/AM) to chelate intracellular Ca 2+ , carbachol still raised intracellular IP 3 level and enhanced TH gene expression. Transient transfection analysis of the 5′ upstream region of TH gene revealed that the AP1 cis ‐acting element at −205 to −199 bp was responsible for carbachol stimulation. But carbachol did not enhance TH gene expression in protein kinase C (PKC)‐activated or down‐regulated cells that had been induced by 5‐min or 24‐h exposure to phorbol 12‐myristate 13‐acetate (PMA), respectively. Thus, Ca 2+ ‐independent PKC may play a role in carbachol‐induced TH gene expression. We demonstrated by gel retardation and competition assays that a DNA sequence containing the wild‐type AP1 site formed the specific DNA‐protein complex. However, treatment with carbachol or PMA did not change the amount of the specific DNA‐protein complex. Our results indicate that stimulation of phospholipase C‐linked muscarinic receptors leads to elevated TH gene expression via AP1‐mediated enhancement in a PKC‐dependent pathway.