title: A novel isoform of liver receptor homolog-1 is regulated by steroidogenic factor-1 and the specificity protein family in ovarian granulosa cells.
abstract: Liver receptor homolog-1 (LRH-1) is a member of the nuclear receptor 5A (NR5A) subfamily. It is expressed in granulosa cells of the ovary and is involved in steroidogenesis and ovulation. To reveal the transcriptional regulatory mechanism of LRH-1, we determined its transcription start site in the ovary using KGN cells, a human granulosa cell tumor cell line. 5'-rapid amplification of cDNA ends PCR revealed that human ovarian LRH-1 was transcribed from a novel transcription start site, termed exon 2o, located 41 bp upstream of the reported exon 2. The novel LRH-1 isoform was expressed in the human ovary but not the liver. Promoter analysis and an EMSA indicated that a steroidogenic factor-1 (SF-1) binding site and a GC box upstream of exon 2o were required for promoter activity, and that SF-1 and specificity protein (Sp)-1/3 bind to the respective regions in ovarian granulosa cells. In KGN cells, transfection of SF-1 increased ovarian LRH-1 promoter activity and SF-1-dependent reporter activity was further enhanced when peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) was cotransfected. In Drosophila SL2 cells, Sp1 was more effective than Sp3 in enhancing promoter activity, and co-transfection of the NR5A-family synergistically increased activity. Infection with adenoviruses expressing SF-1 or PGC-1α induced LRH-1 expression in KGN cells. These results indicate that the expression of human LRH-1 is regulated in a tissue-specific manner, and that the novel promoter region is controlled by the Sp-family, NR5A-family and PGC-1α in ovarian granulosa cells in a coordinated fashion.
authors.affiliation: Department of Biochemistry, University of Fukui, Fukui 910-1193, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Kawabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Yazawa
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kanno
authors.forename: Yoko
authors.initials: Y
authors.lastname: Usami
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizutani
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Imamichi
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Ju
authors.forename: Takehiro
authors.initials: T
authors.lastname: Matsumura
authors.forename: Makoto
authors.initials: M
authors.lastname: Orisaka
authors.forename: Kaoru
authors.initials: K
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D004330:Drosophila; D005260:Female; D005786:Gene Expression Regulation; D006107:Granulosa Cells / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000378:metabolism*; D054339:Steroidogenic Factor 1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D006360:Heat-Shock Proteins; C515057:NR5A1 protein, human; C082631:NR5A2 protein, human; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D018160:Receptors, Cytoplasmic and Nuclear; C497121:SP3 protein, human; D016329:Sp1 Transcription Factor; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; D051705:Sp3 Transcription Factor