Regulation of NGFI-B/Nur77 gene expression in the rat ovary and in leydig tumor cells MA-10

• Published in: Molecular reproduction and development Vol. 75; no. 5; pp. 931 - 939
• Main Authors: Inaoka, Yoshihiko, Yazawa, Takashi, Uesaka, Miki, Mizutani, Tetsuya, Yamada, Kazuya, Miyamoto, Kaoru
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.05.2008; Wiley-Liss
• Subjects: 8-Bromo Cyclic Adenosine Monophosphate - pharmacology; Animals; Biological and medical sciences; Cell Line, Tumor; Chorionic Gonadotropin - pharmacology; Cyclic AMP Response Element-Binding Protein - metabolism; Cyclic AMP-Dependent Protein Kinases - metabolism; Diethylstilbestrol - pharmacology; DNA-Binding Proteins - biosynthesis; Estrogens, Non-Steroidal - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Neoplastic - drug effects; Humans; Hypothalamo-Hypophyseal System - metabolism; Leydig Cell Tumor - metabolism; Leydig Cell Tumor - pathology; Luteinizing Hormone - pharmacology; MA-10; Mice; Molecular and cellular biology; Molecular genetics; NGFI-B/Nur77; Nuclear Receptor Subfamily 4, Group A, Member 1; ovary; Proto-Oncogene Proteins c-jun - metabolism; Rats; Receptors, Steroid - biosynthesis; Response Elements; Theca Cells - metabolism; Theca Cells - pathology; Transcription Factor AP-1; NGFI-B/Nur77; MA-10; Rat; Rodentia; Testicle; Gene expression; Male genital system; In vitro; Leydig cell; Ovary; Vertebrata; Regulation(control); Mammalia; Animal; Female genital system; Tumor cell; Quantitative analysis
• ISSN: 1040-452X; 1098-2795; 1098-2795
• DOI: 10.1002/mrd.20788

NR4A1, also called NGFI‐B in the rat, Nur77 in the mouse and TR3 in humans, belongs to the orphan nuclear steroid hormone receptor superfamily and is one of the immediate‐early genes. In the endocrine organs, including the gonads, NGFI‐B/Nur77 gene expression is rapidly induced by pituitary hormones. NGFI‐B/Nur77 expression was found to be rapidly reduced by an estrogenic endocrine disrupter, diethylstilbestrol (DES) in theca interna cells of immature rat ovaries. DES treatment also triggered a rapid decrease of serum luteinizing hormone (LH) levels, suggesting that DES acts on the hypothalamo–pituitary axis to suppress LH secretion from the pituitary. The transcriptional regulation of NGFI‐B/Nur77 by LH/human chorionic gonadotropin (hCG) or 8‐bromoadenosine 3′–5′‐cyclic monophosphate (8 Br‐cAMP) was examined in mouse Leydig tumor cells MA‐10. Luciferase assays using NGFI‐B/Nur77 promoter constructs and electric mobility shift assays (EMSA) showed that NGFI‐B/Nur77 gene expression was mediated through three of the four activator protein‐1 (AP‐1)‐like sites, namely the −233 AP‐1, −213 AP‐1 and −69 AP‐1 sites adjacent to the transcription start site of the NGFI‐B/Nur77 promoter. We also demonstrated here that both the Jun family and cAMP‐responsive element binding (CREB) proteins bind to the −233 AP‐1 site, whereas the main binding protein to the −213 AP‐1 site was CREB, and Jun family protein to the −69 AP‐1 site, respectively. The rapid induction of NGFI‐B/Nur77 gene expression by LH/hCG in MA‐10 cells appears to be mediated by both CREB and Jun family proteins through the cAMP‐protein kinase A (PKA) pathway. Mol. Reprod. Dev. 75: 931–939, 2008. © 2007 Wiley‐Liss, Inc.