Pituitary adenylate cyclase-activating polypeptide and cyclic adenosine 3',5'-monophosphate stimulate the promoter activity of the rat gonadotropin-releasing hormone receptor gene via a bipartite response element in gonadotrope-derived cells.
Specific type I receptors for pituitary adenylate cyclase-activating polypeptide (PACAP) are present in gonadotrope cells of the anterior pituitary gland. By transient transfection of mouse gonadotrope-derived alphaT3-1 cells, which are direct targets for PACAP and express gonadotropin-releasing hormone receptor (GnRH-R), a marker of the gonadotrope lineage, we provide the first evidence that PACAP stimulates rat GnRH-R gene promoter activity. The EC(50) of this stimulation is compatible with a mediation via activation of the cyclic AMP-dependent signaling pathway and, consistently, co-transfection of an expression vector expressing the protein kinase A inhibitor causes reduction in PACAP as well as cholera toxin-stimulated promoter activity. Deletion and mutational analyses indicate that PACAP activation necessitates a bipartite response element that consists of a first region (-272/-237) termed PACAP response element (PARE) I that includes a steroidogenic factor-1 (SF-1)-binding site and a second region (-136/-101) referred to as PARE II that contains an imperfect cyclic AMP response element. Gel shift experiments indicate the specific binding of the SF-1 and a potential SF-1-interacting factor to PARE I while a protein immunologically related to the cyclic AMP response element-binding protein interacts with PARE II. These findings suggest that PACAP might regulate the GnRH-R gene at the transcriptional level, providing novel insights into the regulation of pituitary-specific genes by hypothalamic hypophysiotropic signals.
Pincas
H
H
Endocrinologie Cellulaire et Moléculaire de la Reproduction, Université Pierre et Marie Curie, Centre National de la Recherche Scientifique, ESA 7080, 75252 Paris, France.
Laverrière
J N
JN
Counis
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R
D000818:Animals; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D051717:Fushi Tarazu Transcription Factors; D005796:Genes; D018398:Homeodomain Proteins; D046911:Macromolecular Substances; D051379:Mice; D008954:Models, Biological; D009154:Mutation; D009479:Neuropeptides / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D011966:Receptors, LHRH / Q000235:genetics*; D020218:Response Elements; D015398:Signal Transduction; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation
C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D046911:Macromolecular Substances; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018160:Receptors, Cytoplasmic and Nuclear; D011966:Receptors, LHRH; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse; C515060:steroidogenic factor 1, rat; D002772:Cholera Toxin; D000242:Cyclic AMP; D015500:Chloramphenicol O-Acetyltransferase; D017868:Cyclic AMP-Dependent Protein Kinases