A steroidogenic factor-1 binding element is essential for basal human ACTH receptor gene transcription.
We have previously shown that the promoter of the human ACTH receptor (ACTH-R) contains, at -35 bp, a binding site for the steroidogenic factor 1 (SF-1), an orphan nuclear receptor which could be responsible for the transcriptional activity of this promoter. In the present study, electrophoretic mobility shift assays demonstrated that the sequence -43/-19 bound the SF-1 protein present in the nuclear extracts of adrenocortical cells. Mutation of the SF-1 binding site markedly reduced (40%) the basal transcription of the reporter gene in Y-1 cells transfected with the mutated p(-56/+22)GH construct compared to the wild-type construct. These results demonstrate that the SF-1 binding element present in this fragment is required for the basal promoter activity of the human ACTH-R gene. In addition, other binding elements located upstream from this characterized SF-1 binding site are involved in the full basal promoter activity of the human ACTH-R since transfection studies with a longer p(-1017/+22)GH construct resulted in a higher GH release than with the p(-56/+22)GH construct.
Marchal
R
R
INSERM-INRA U 418, Hôpital Debrousse, Lyon, France.
Naville
D
D
Durand
P
P
Begeot
M
M
Penhoat
A
A
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D002417:Cattle; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D006801:Humans; D008545:Melanoma; D051379:Mice; D011401:Promoter Regions, Genetic; D018043:Receptors, Corticotropin / Q000235:genetics* / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C515057:NR5A1 protein, human; D018043:Receptors, Corticotropin; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse