A calcium/calmodulin-dependent activation of ERK1/2 mediates JunD phosphorylation and induction of nur77 and 20alpha-hsd genes by prostaglandin F2alpha in ovarian cells.
We have previously demonstrated that prostaglandin F(2alpha) (PGF(2alpha)) induces a rapid and transient expression of Nur77 in luteal cells. We have shown that Nur77 plays an important role in ovarian physiology by mediating the PGF(2alpha) induction of 20alpha-HSD, a steroidogenic enzyme involved in the catabolism of progesterone. In this report we established, using luteinized granulosa cells, that PGF(2alpha) stimulates in vitro nur77 expression in a time- and dose-dependent manner. Serial 5'-deletion of the nur77 promoter revealed that the necessary and sufficient elements for PGF(2alpha) induction of Nur77 promoter activity are located between the nucleotides -86 and -33 upstream of the transcription start site, this region containing two AP1 elements. JunD binds to these AP1 sites, but its binding is not stimulated by PGF(2alpha). However, mutation of the AP1 sites as well as a dominant-negative JunD abolished nur77 induction by PGF(2alpha). PGF(2alpha) induces phosphorylation of JunD bound to the nur77 promoter. Stimulation of nur77 expression and JunD phosphorylation were prevented by inhibitors of calcium, calmodulin, or ERK1/2 kinase. PGF(2alpha)-induced ERK1/2 phosphorylation was prevented by calcium/calmodulin inhibitors. We conclude that activation of JunD through a calmodulim-dependent activation of ERK1/2 mediates nur77 induction by PGF(2alpha). Finally, we demonstrated that this molecular mechanism also mediates 20alpha-hsd induction.
Stocco
Carlos O
CO
Department of Physiology and Biophysics, University of Illinois College of Medicine, Chicago, Illinois 60612, USA.
Lau
Lester F
LF
Gibori
Geula
G
D015089:20-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000494:pharmacology; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015237:Dinoprost / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D010766:Phosphorylation; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid / Q000235:genetics; D017384:Sequence Deletion; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics*
D002147:Calmodulin; D004268:DNA-Binding Proteins; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D016755:Proto-Oncogene Proteins c-jun; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D015237:Dinoprost; D015089:20-Hydroxysteroid Dehydrogenases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium