Regulation of rat dopamine beta-hydroxylase gene transcription by early growth response gene 1 (Egr1).
Egr1, a transcription factor rapidly induced by various stimuli including stress, can elevate transcription of genes for the catecholamine biosynthetic enzymes TH and PNMT. To examine if Egr1 also regulates dopamine beta-hydroxylase (DBH) gene expression, PC12 cells were transfected with expression vector for full length or truncated inactive Egr1 and various DBH promoter-driven luciferase constructs. While Egr1 elevated TH promoter activity, DBH promoter activity was reduced. The reduction occurred as early as 4 h and reached maximal inhibition 16-40 h after transfection. Egr1 also reduced the expression of endogenous DBH mRNA and the induction of DBH promoter activity by cAMP. These effects were not observed with truncated Egr1 lacking the DNA binding domain. The first 247, but not 200, nucleotides of DBH promoter are sufficient for this suppression. Several putative Egr1 motifs were identified, and mutagenesis showed that the motif at -227/-224 is required. Binding of Egr1 to this region of the DBH promoter was verified by chromatin immunoprecipitation and electrophoretic mobility shift assays. This study demonstrates that DBH promoter contains at least one functional Egr1 motif; and indicates, for the first time, that Egr1 can play an inhibitory role in regulation of DBH gene transcription.
Cheng
Shu-Yuan
SY
Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595, USA.
Serova
Lidia I
LI
Glazkova
Dina
D
Sabban
Esther L
EL
D000704:Analysis of Variance; D000818:Animals; D047369:Chromatin Immunoprecipitation / Q000379:methods; D000242:Cyclic AMP / Q000494:pharmacology; D004299:Dopamine beta-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000502:physiology; D016716:PC12 Cells; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000502:physiology; D051381:Rats; D013997:Time Factors; D014162:Transfection
D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D000242:Cyclic AMP; D008156:Luciferases; D004299:Dopamine beta-Hydroxylase