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Ovarian follicles lacking FSH or FSH receptors fail to progress to a preovulatory stage, resulting in infertility. One hallmark of the preovulatory follicle is the presence of luteinizing hormone/choriogonadotropin receptors (LHCGR) on granulosa cells (GCs). However, the mechanisms by which FSH induces Lhcgr gene expression are poorly understood. Our results show that protein kinase A (PKA) and phosphoinositide 3-kinase (PI3K)/AKT pathways are required for FSH to activate both the murine Lhcgr-luciferase reporter and expression of Lhcgr mRNA in rat GCs. Based on results showing that an adenovirus (Ad) expressing a steroidogenic factor 1 (SF1) mutant that cannot bind β-catenin abolished FSH-induced Lhcgr mRNA, we evaluated the role of β-catenin in the regulation of Lhcgr gene expression. FSH promoted the PKA-dependent, PI3K-independent phosphorylation of β-catenin on Ser552 and Ser665. FSH activated the β-catenin/T-cell factor (TCF) artificial promoter-reporter TOPFlash via a PKA-dependent, PI3K-independent pathway, and dominant-negative (DN) TCF abolished FSH-activated Lhcgr-luciferase reporter and induction of Lhcgr mRNA. Microarray analysis of GCs treated with Ad-DN-TCF and FSH identified the Lhcgr as the most down-regulated gene. Chromatin immunoprecipitation results placed β-catenin phosphorylated on Ser552 and Ser675 and SF1 on the Lhcgr promoter in FSH-treated GCs; TCF3 was constitutively associated with the Lhcgr promoter. Transduction with an Ad-phospho-β-catenin mutant (Ser552/665/Asp) enhanced Lhcgr mRNA expression in FSH-treated cells greater than 3-fold. Finally, we identified a recognized PI3K/AKT target, forkhead box O1, as a negative regulator of Lhcgr mRNA expression. These results provide new understanding of the complex regulation of Lhcgr gene expression in GCs.
570, 610, Down-Regulation, Nerve Tissue Proteins, Rats, Sprague-Dawley, Phosphatidylinositol 3-Kinases, Receptors, Gonadotropin, Ovarian Follicle, Animals, RNA, Messenger, Phosphorylation, Promoter Regions, Genetic, Cells, Cultured, Granulosa Cells, Forkhead Transcription Factors, Receptors, LH, Cyclic AMP-Dependent Protein Kinases, Rats, Gene Expression Regulation, Female, Follicle Stimulating Hormone, Proto-Oncogene Proteins c-akt
570, 610, Down-Regulation, Nerve Tissue Proteins, Rats, Sprague-Dawley, Phosphatidylinositol 3-Kinases, Receptors, Gonadotropin, Ovarian Follicle, Animals, RNA, Messenger, Phosphorylation, Promoter Regions, Genetic, Cells, Cultured, Granulosa Cells, Forkhead Transcription Factors, Receptors, LH, Cyclic AMP-Dependent Protein Kinases, Rats, Gene Expression Regulation, Female, Follicle Stimulating Hormone, Proto-Oncogene Proteins c-akt
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 63 | |
popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |