title: C/EBPβ (CCAAT/enhancer-binding protein β) mediates progesterone production through transcriptional regulation in co-operation with SF-1 (steroidogenic factor-1).
abstract: The transcription factor SF-1 (steroidogenic factor-1) is a master regulator of steroidogenesis. Previously, we have found that SF-1 induces the differentiation of mesenchymal stem cells into steroidogenic cells. To elucidate the molecular mechanisms of SF-1-mediated functions, we attempted to identify protein components of the SF-1 nuclear protein complex in differentiated cells. SF-1 immunoaffinity chromatography followed by MS/MS analysis was performed, and 24 proteins were identified. Among these proteins, we focused on C/EBPβ (CCAAT/enhancer-binding protein β), which is an essential transcription factor for ovulation and luteinization, as the transcriptional mechanisms of C/EBPβ working together with SF-1 are poorly understood. C/EBPβ knockdown attenuated cAMP-induced progesterone production in granulosa tumour-derived KGN cells by altering STAR (steroidogenic acute regulatory protein), CYP11A1 (cytochrome P450, family 11, subfamily A, polypeptide 1) and HSD3B2 (hydroxy-δ-5-steroid dehydrogenase, 3β- and steroid δ-isomerase 2) expression. EMSA and ChIP assays revealed novel C/EBPβ-binding sites in the upstream regions of the HSD3B2 and CYP11A1 genes. These interactions were enhanced by cAMP stimulation. Luciferase assays showed that C/EBPβ-responsive regions were found in each promoter and C/EBPβ is involved in the cAMP-induced transcriptional activity of these genes together with SF-1. These results indicate that C/EBPβ is an important mediator of progesterone production by working together with SF-1, especially under tropic hormone-stimulated conditions.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizutani
authors.affiliation: *Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Ju
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Imamichi
authors.affiliation: ‡Department of Molecular Pharmacology, National Cerebral and Cardiovascular Center Research Institute, Osaka 565-8565, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Osaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Yazawa
authors.forename: Shinya
authors.initials: S
authors.lastname: Kawabe
authors.forename: Shin
authors.initials: S
authors.lastname: Ishikane
authors.affiliation: *Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Matsumura
authors.affiliation: *Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kanno
authors.affiliation: *Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Yasue
authors.initials: Y
authors.lastname: Kamiki
authors.affiliation: *Department of Biochemistry, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Kimura
authors.affiliation: ‡Department of Molecular Pharmacology, National Cerebral and Cardiovascular Center Research Institute, Osaka 565-8565, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Minamino
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D010750:Phosphoproteins; D011374:Progesterone / Q000096:biosynthesis* / Q000235:genetics; D011375:Progesterone Reductase / Q000235:genetics; D054339:Steroidogenic Factor 1 / Q000502:physiology*; D053719:Tandem Mass Spectrometry; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D010750:Phosphoproteins; D054339:Steroidogenic Factor 1; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; C533068:3 beta-hydroxysteroid dehydrogenase type II; D011375:Progesterone Reductase; D002786:Cholesterol Side-Chain Cleavage Enzyme