Hormonal regulation of the human ghrelin receptor gene transcription.
The aim of this study is to clarify the hormonal regulation of the human ghrelin receptor gene expression in GH(3) cells transfected with our previously cloned 5'-flanking region inserted into a luciferase reporter vector. Phorbor 12-tetradecanoate 13-acetate (TPA) with simultaneous addition of Bay K8644 mimicking ghrelin action caused a significant inhibition of the luciferase activity through the ghrelin receptor gene upstream proximal to -669 but not to -608 base pairs (bp). Glucocorticoid caused a weak but significant inhibition of the luciferase activity through the ghrelin receptor gene upstream proximal to -531 but not to -475 bp. Electrophoretic mobility shift assay resulted in binding of oligonucleotides between -669 and -640 bp, and between -520 and -491 bp to GH(3) cell nuclear proteins unlike AP(2) or glucocorticoid receptor. These results suggest that both TPA/Bay K8644 and glucocorticoid downregulate human ghrelin receptor gene expression through the transcriptional mechanism involving some nuclear factors.
Kaji
H
H
Department of Physiology and Biochemistry, College of Nursing Art and Science, Hyogo, Akashi 673-8588, Japan. kajis@hi-net.zaq.ne.jp
Kishimoto
M
M
Kirimura
T
T
Iguchi
G
G
Murata
M
M
Yoshioka
S
S
Iida
K
K
Okimura
Y
Y
Yoshimoto
Y
Y
Chihara
K
K
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D050882:CREB-Binding Protein; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics; D010902:Pituitary Gland / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics*; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D012045:Regulatory Sequences, Nucleic Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D015534:Trans-Activators; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D004247:DNA; D008156:Luciferases; D050882:CREB-Binding Protein; C494363:CREBBP protein, human; D013755:Tetradecanoylphorbol Acetate; D006854:Hydrocortisone