Drean YL ; Liu D ; Wong AO ; Xiong F ; Hew CL ;

Mol Endocrinol vol. 10 (3)   pp. 217-29, Mar 1996

Research Institute Hospital for Sick Children, University of Toronto, Ontario, Canada.

The orphan nuclear receptor steroidogenic factor-1 (SF-1) regulates the expression of several genes involved in the reproductive function and development of the adrenal, the gonads, and the pituitary gonadotropes. It also confers the gonadotrope-specific expression of the glycoprotein hormone a subunit gene by the binding to a gonadotrope-specific element (GSE). In this study, we have shown that SF-1 transactivates the salmon gonadotropin II beta subunit (sGTHII beta) gene expression. SF-1 alone offered a slight but significant enhancement on sGTHII beta promoter activity (7.2 +/- 0.6 fold). However, it stimulated sGTHII beta gene expression dramatically (127 +/- 37 fold) when combined with the estrogen receptor (ER). This synergistic interaction was specific for sGTHII beta promoter as well as for both SF-1 and ER and was estradiol- dose dependent. 5'-Deletion studies of the sGTHII beta promoter identified two putative SF-1 binding sites (GSE) and one previously identified proximal estrogen-responsive element (pERE) at -274 bp involved in this activation. The two GSE sequences located at -354 bp (sGSE(3) and -162 bp (sGSE(2) upstream of the transcription site, although imperfect as compared with the consensus GSE, bound specifically to the in vitro-translated mouse SF-1 protein. 5'-Deletion studies, competition experiments, and site-directed mutagenesis showed that binding to pERE and GSE(2) were necessary for the SF-1/ER synergistic effect. These studies suggest that the synergistic interaction of SF-1 and ER, possibly through cooperative binding or protein-protein interaction, is essential in conferring a cell type- specific expression of the GTHII beta subunit gene.

Animal ;  Comparative Study ;  Consensus Sequence ;  DNA-Binding Proteins: physiology ;  Gene Expression Regulation ;  Genes,Structural ;  Gonadotropins,Pituitary: biosynthesis: genetics ;  Hela Cells ;  Human ;  Mice ;  Mutagenesis,Site-Directed ;  Organ Specificity ;  Promoter Regions (Genetics) ;  Receptors,Estradiol: physiology ;  Recombinant Fusion Proteins: biosynthesis ;  Regulatory Sequences,Nucleic Acid ;  Salmon: genetics ;  Sequence Alignment ;  Sequence Homology,Amino Acid ;  Stimulation,Chemical ;  Support,Non-U.S.Gov't ;  Transcription Factors: physiology ;  Transcription,Genetic ;  Transfection ;  28120 ;