Involvement of cyclic adenosine 5'-monophosphate response element-binding protein, steroidogenic factor 1, and Dax-1 in the regulation of gonadotropin-inducible ovarian transcription factor 1 gene expression by follicle-stimulating hormone in ovarian granulosa cells.
Upon FSH stimulation, many genes are acutely induced in granulosa cells. Gonadotropin-inducible ovarian transcription factor 1 (GIOT1) represents a novel member of the group of transcriptional repressors that belong to one such gene. To investigate the mechanism of this transcriptional activation, a rat GIOT1 promoter region was isolated and subsequently ligated to a luciferase vector and transfected to freshly prepared granulosa cells. A luciferase reporter gene driven by 0.8 kb of the GIOT1 5'-flanking region was highly expressed in response to FSH. Deletion and mutational analyses indicated that two response elements, including a steroidogenic factor 1 (SF-1) site and a cAMP response element (CRE), are required for the activation of the gene by FSH. Gel shift experiments also indicated that SF-1 and CRE binding protein specifically bind to each site. To reveal the relationship between SF-1 and the cAMP-dependent protein kinase A pathway, cotransfection was performed using SF-1-deficient cells. Although SF-1 and the catalytic subunit of protein kinase A individually caused a modest stimulation of the GIOT1 promoter, dramatic synergistic effects were observed in the case of cotransfection. Although the amount of SF-1 remained unchanged in response to FSH in granulosa cells, Dax-1 expression immediately decreased. The ectopic expression of Dax-1 inhibited the SF-1-dependent GIOT1 promoter activity. These results suggest that the synergistic action of CRE binding protein and SF-1 and the rapid down-regulation of Dax-1 are responsible for the acute induction of GIOT1 gene by gonadotropin.
Yazawa
Takashi
T
Department of Biochemistry, Fukui Medical University, Fukui 910-1193, Japan.
Mizutani
Tetsuya
T
Yamada
Kazuya
K
Kawata
Hiroko
H
Sekiguchi
Toshio
T
Yoshino
Miki
M
Kajitani
Takashi
T
Shou
Zhangfei
Z
Miyamoto
Kaoru
K
D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology*; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000502:physiology*; D015536:Down-Regulation; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D051717:Fushi Tarazu Transcription Factors; D015870:Gene Expression / Q000187:drug effects; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D018398:Homeodomain Proteins; D008969:Molecular Sequence Data; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid / Q000502:physiology*; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
D017362:Cyclic AMP Response Element-Binding Protein; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; C486721:Giot1 protein, rat; D018398:Homeodomain Proteins; C539967:Nr0b1 protein, rat; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515060:steroidogenic factor 1, rat; D005640:Follicle Stimulating Hormone