Switching of NR5A proteins associated with the inhibin alpha-subunit gene promoter after activation of the gene in granulosa cells.
The inhibin alpha-subunit gene is transcriptionally activated by FSH in ovarian granulosa cells during follicular growth. We have investigated the roles of the NR5A family nuclear receptors steroidogenic factor 1 (SF-1) and liver receptor homolog 1 (LRH-1) in transcriptional activation of the inhibin alpha-subunit gene. Transfection assays using an inhibin alpha-subunit promoter reporter in GRMO2 granulosa cells show that LRH-1 and SF-1 act similarly to increase promoter activity, and that the activity of both transcription factors is augmented by the coactivators cAMP response element-binding protein-binding protein and steroid receptor coactivator 1. However, chromatin immunoprecipitation experiments illustrate differential dynamic association of LRH-1 and SF-1 with the alpha-subunit inhibin promoter in both primary cells and the GRMO2 granulosa cell line such that hormonal stimulation of transcription results in an apparent replacement of SF-1 with LRH-1. Transcriptional stimulation of the inhibin alpha-subunit gene is dependent on MAPK kinase activity, as is the dynamic association/disassociation of SF-1 and LRH-1 with the promoter. Inhibition of the phosphatidylinositol 3-kinase signaling pathway influences promoter occupancy and transcriptional activation by SF-1 but not LRH-1, suggesting a possible mechanistic basis for the distinct functions of these NR5A proteins in inhibin alpha-subunit gene regulation.
Weck
Jennifer
J
Department of Biochemistry, Molecular Biology, and Cell Biology, and Center for Reproductive Science, 2205 Tech Drive, Northwestern University, Evanston, Illinois 60208, USA.
Mayo
Kelly E
KE
D000818:Animals; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D005260:Female; D006107:Granulosa Cells / Q000378:metabolism*; D051548:Histone Acetyltransferases; D018398:Homeodomain Proteins / Q000378:metabolism*; D007265:Inhibins / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D056920:Nuclear Receptor Coactivator 1; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011401:Promoter Regions, Genetic; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D017362:Cyclic AMP Response Element-Binding Protein; D051548:Histone Acetyltransferases; D018398:Homeodomain Proteins; D007265:Inhibins; D020929:Mitogen-Activated Protein Kinase Kinases; D056920:Nuclear Receptor Coactivator 1; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C431936:Nr5a2 protein, mouse; C094377:inhibin-alpha subunit; C515058:steroidogenic factor 1, mouse; C538861:Ncoa1 protein, mouse