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

• Published in: Endocrinology (Philadelphia) Vol. 144; no. 5; pp. 1920 - 1930
• Main Authors: Yazawa, Takashi, Mizutani, Tetsuya, Yamada, Kazuya, Kawata, Hiroko, Sekiguchi, Toshio, Yoshino, Miki, Kajitani, Takashi, Shou, Zhangfei, Miyamoto, Kaoru
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 01.05.2003
• Subjects: Animals; Base Sequence - genetics; Biological and medical sciences; Cells, Cultured; Cyclic AMP Response Element-Binding Protein - physiology; DAX-1 Orphan Nuclear Receptor; DNA-Binding Proteins - physiology; Down-Regulation; Female; Follicle Stimulating Hormone - pharmacology; Fundamental and applied biological sciences. Psychology; Fushi Tarazu Transcription Factors; Gene Expression - drug effects; Granulosa Cells - drug effects; Granulosa Cells - metabolism; Homeodomain Proteins; Molecular Sequence Data; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; Receptors, Retinoic Acid - physiology; Repressor Proteins; Steroidogenic Factor 1; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription Factors - physiology
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/en.2002-221070

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.