The role of the orphan nuclear receptor, liver receptor homologue-1, in the regulation of human corpus luteum 3beta-hydroxysteroid dehydrogenase type II.
After ovulation, ovarian 3beta-hydroxysteroid dehydrogenase type II (HSD3B2) expression increases to enhance the shift of steroidogenesis toward progesterone biosynthesis. Steroidogenic factor-1 (SF-1) is a transcription factor for several genes encoding steroidogenic enzymes. However, the level of SF-1 expression decreases in the human corpus luteum (CL) after ovulation. Liver receptor homolog-1 (LRH-1) is another member of the orphan nuclear receptor family. We hypothesize that LRH-1, rather than SF-1, plays an essential role in the regulation of corpus luteum steroidogenesis. Semiquantitative RT-PCR and real-time PCR were performed to quantify the level of LRH-1 expression and correlate with HSD3B2 level. Cell transfection, mutation analysis, and EMSA were performed to examine the role of LRH-1 in the regulation of HSD3B2. LRH-1 expression was higher in CL, compared with mature ovarian follicles. Cotransfection of granulosa cells with HSD3B2 and LRH-1 resulted in a 10-fold increase of transcription. DAX-1 inhibited LRH-1-stimulated HSD3B2, which was maintained in the presence of dibutyryl cAMP. Mutation of the either of the two putative LRH-1 binding sites, which were confirmed by EMSA, in the HSD3B2 promoter decreased LRH-1 stimulation. Our findings suggest that LRH-1 is highly expressed in CL, and it plays an essential role in the regulation of HSD3B2.
Peng
Noel
N
Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas Texas 75390-9032, USA.
Kim
Joung W
JW
Rainey
William E
WE
Carr
Bruce R
BR
Attia
George R
GR
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000201:enzymology*; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000494:pharmacology; D004586:Electrophoresis; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000502:physiology*; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins / Q000494:pharmacology; D013237:Stereoisomerism; D054339:Steroidogenic Factor 1; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D015533:Transcriptional Activation / Q000502:physiology
D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D007527:Isoenzymes; C539965:NR0B1 protein, human; C515057:NR5A1 protein, human; C539966:Nr0b1 protein, mouse; C431936:Nr5a2 protein, mouse; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; C515058:steroidogenic factor 1, mouse; D015096:3-Hydroxysteroid Dehydrogenases