This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by White, B. R. Articles by Clay, C. M. Search for Related Content PubMed PubMed Citation Articles by White, B. R. Articles by Clay, C. M.

Homologous Regulation of the Gonadotropin-Releasing Hormone Receptor Gene Is Partially Mediated by Protein Kinase C Activation of an Activator Protein-1 Element

Animal Reproduction and Biotechnology Laboratory (B.R.W., D.L.D., C.M.C.) Department of Physiology College of Veterinary Medicine and Biomedical Sciences Foothills Campus, Colorado State University Fort Collins, Colorado 80523
Department of Biomedical Sciences (J.M.M., M.S.R.) Cornell University Ithaca, New York 14853

Homologous regulation of GnRH receptor (GnRHR) gene expression is an established mechanism for controlling the sensitivity of gonadotropes to GnRH. We have found that expression of the GnRHR gene in the gonadotrope-derived T3–1 cell line is mediated by a tripartite enhancer that includes a consensus activator protein-1 (AP-1) element, a binding site for SF-1 (steroidogenic factor-1), and an element we have termed GRAS (GnRHR-activating sequence). Further, in transgenic mice, approximately 1900 bp of the murine GnRHR gene promoter are sufficient for tissue-specific expression and GnRH responsiveness. The present studies were designed to further delineate the molecular mechanisms underlying GnRH regulation of GnRHR gene expression. Vectors containing 600 bp of the murine GnRHR gene promoter linked to luciferase (LUC) were transiently transfected into T3–1 cells and exposed to treatments for 4 or 6 h. A GnRH-induced, dose-dependent increase in LUC expression of the -600 promoter was observed with maximal induction of LUC noted at 100 nM GnRH. We next tested the ability of GnRH to stimulate expression of vectors containing mutations in each of the components of the tripartite enhancer. GnRH responsiveness was lost in vectors containing mutations in AP-1. Gel mobility shift data revealed binding of fos/jun family members to the AP-1 element of the murine GnRHR promoter. Treatment with GnRH or phorbol-12-myristate-13-acetate (PMA) (100 nM), but not forskolin (10 µM), increased LUC expression, which was blocked by the protein kinase C (PKC) inhibitor, GF109203X (100 nM), and PKC down-regulation (10 nM PMA for 20 h). In addition, a specific MEK1/MEK2 inhibitor, PD98059 (60 µM), reduced the GnRH and PMA responses whereas the L-type voltage-gated calcium channel agonist, ±BayK 8644 (5 µM), and antagonist, nimodipine (250 nM), had no effect on GnRH responsiveness. Furthermore, treatment of T3–1 cells with 100 nM GnRH stimulated phosphorylation of both p42 and p44 forms of extracellular signal-regulated kinase (ERK), which was completely blocked with 60 µM PD98059. We suggest that GnRH regulation of the GnRHR gene is partially mediated by an ERK-dependent activation of a canonical AP-1 site located in the proximal promoter of the GnRHR gene.

This article has been cited by other articles:

				T. B. Salisbury, A. K. Binder, and J. H. Nilson Welcoming {beta}-Catenin to the Gonadotropin-Releasing Hormone Transcriptional Network in Gonadotropes Mol. Endocrinol., June 1, 2008; 22(6): 1295 - 1303. [Abstract] [Full Text] [PDF]

				A. M. Navratil, J. G. Knoll, J. D. Whitesell, S. A. Tobet, and C. M. Clay Neuroendocrine Plasticity in the Anterior Pituitary: Gonadotropin-Releasing Hormone-Mediated Movement in Vitro and in Vivo Endocrinology, April 1, 2007; 148(4): 1736 - 1744. [Abstract] [Full Text] [PDF]

				B. D. Cherrington, T. A. Farmerie, C. A. Lents, J. D. Cantlon, M. S. Roberson, and C. M. Clay Activin Responsiveness of the Murine Gonadotropin-Releasing Hormone Receptor Gene Is Mediated by a Composite Enhancer Containing Spatially Distinct Regulatory Elements Mol. Endocrinol., April 1, 2005; 19(4): 898 - 912. [Abstract] [Full Text] [PDF]

				C. K. Cheng and P. C. K. Leung Molecular Biology of Gonadotropin-Releasing Hormone (GnRH)-I, GnRH-II, and Their Receptors in Humans Endocr. Rev., April 1, 2005; 26(2): 283 - 306. [Abstract] [Full Text] [PDF]

				K.-Y. Kam, K.-H. Jeong, E. R. Norwitz, E. M. Jorgensen, and U. B. Kaiser Oct-1 and Nuclear Factor Y Bind to the SURG-1 Element to Direct Basal and Gonadotropin-Releasing Hormone (GnRH)-Stimulated Mouse GnRH Receptor Gene Transcription Mol. Endocrinol., January 1, 2005; 19(1): 148 - 162. [Abstract] [Full Text] [PDF]

				L L Burger, D J Haisenleder, A C Dalkin, and J C Marshall Regulation of gonadotropin subunit gene transcription J. Mol. Endocrinol., December 1, 2004; 33(3): 559 - 584. [Abstract] [Full Text] [PDF]

				K.-H. Jeong, W. W. Chin, and U. B. Kaiser Essential Role of the Homeodomain for Pituitary Homeobox 1 Activation of Mouse Gonadotropin-Releasing Hormone Receptor Gene Expression through Interactions with c-Jun and DNA Mol. Cell. Biol., July 15, 2004; 24(14): 6127 - 6139. [Abstract] [Full Text] [PDF]

				R. M. Luque, R. D. Kineman, S. Park, X.-D. Peng, F. Gracia-Navarro, J. P. Castano, and M. M. Malagon Homologous and Heterologous Regulation of Pituitary Receptors for Ghrelin and Growth Hormone-Releasing Hormone Endocrinology, July 1, 2004; 145(7): 3182 - 3189. [Abstract] [Full Text] [PDF]

				P. R. Manna, D. W. Eubank, and D. M. Stocco Assessment of the Role of Activator Protein-1 on Transcription of the Mouse Steroidogenic Acute Regulatory Protein Gene Mol. Endocrinol., March 1, 2004; 18(3): 558 - 573. [Abstract] [Full Text] [PDF]

				F. Liu, D. A. Austin, and N. J. G. Webster Gonadotropin-Releasing Hormone-Desensitized L{beta}T2 Gonadotrope Cells Are Refractory to Acute Protein Kinase C, Cyclic AMP, and Calcium-Dependent Signaling Endocrinology, October 1, 2003; 144(10): 4354 - 4365. [Abstract] [Full Text] [PDF]

				A. M. Navratil, S. P. Bliss, K. A. Berghorn, J. M. Haughian, T. A. Farmerie, J. K. Graham, C. M. Clay, and M. S. Roberson Constitutive Localization of the Gonadotropin-releasing Hormone (GnRH) Receptor to Low Density Membrane Microdomains Is Necessary for GnRH Signaling to ERK J. Biol. Chem., August 22, 2003; 278(34): 31593 - 31602. [Abstract] [Full Text] [PDF]

				H. Sadie, G. Styger, and J. Hapgood Expression of the Mouse Gonadotropin-Releasing Hormone Receptor Gene in {alpha}T3-1 Gonadotrope Cells Is Stimulated by Cyclic 3',5'-Adenosine Monophosphate and Protein Kinase A, and Is Modulated by Steroidogenic Factor-1 and Nur77 Endocrinology, May 1, 2003; 144(5): 1958 - 1971. [Abstract] [Full Text] [PDF]

				B. S. Ellsworth, B. R. White, A. T. Burns, B. D. Cherrington, A. M. Otis, and C. M. Clay c-Jun N-Terminal Kinase Activation of Activator Protein-1 Underlies Homologous Regulation of the Gonadotropin-Releasing Hormone Receptor Gene in {alpha}T3-1 Cells Endocrinology, March 1, 2003; 144(3): 839 - 849. [Abstract] [Full Text] [PDF]

				E. R. Norwitz, S. Xu, J. Xu, L. B. Spiryda, J. S. Park, K.-H. Jeong, E. A. McGee, and U. B. Kaiser Direct Binding of AP-1 (Fos/Jun) Proteins to a SMAD Binding Element Facilitates Both Gonadotropin-releasing Hormone (GnRH)- and Activin-mediated Transcriptional Activation of the Mouse GnRH Receptor Gene J. Biol. Chem., September 27, 2002; 277(40): 37469 - 37478. [Abstract] [Full Text] [PDF]

				V. V. Vasilyev, M. A. Lawson, D. Dipaolo, N. J. G. Webster, and P. L. Mellon Different Signaling Pathways Control Acute Induction versus Long-Term Repression of LH{beta} Transcription by GnRH Endocrinology, September 1, 2002; 143(9): 3414 - 3426. [Abstract] [Full Text] [PDF]

				E. R. Norwitz, S. Xu, K.-H. Jeong, G. Y. Bedecarrats, L. D. Winebrenner, W. W. Chin, and U. B. Kaiser Activin A Augments GnRH-Mediated Transcriptional Activation of the Mouse GnRH Receptor Gene Endocrinology, March 1, 2002; 143(3): 985 - 997. [Abstract] [Full Text]

				T. Zhang, M. W. Wolfe, and M. S. Roberson An Early Growth Response Protein (Egr) 1 cis-Element Is Required for Gonadotropin-releasing Hormone-induced Mitogen-activated Protein Kinase Phosphatase 2 Gene Expression J. Biol. Chem., November 30, 2001; 276(49): 45604 - 45613. [Abstract] [Full Text] [PDF]

				G. Maya-Nunez and P. Michael Conn Cyclic Adenosine 3',5'-Monophosphate (cAMP) and cAMP Responsive Element-Binding Protein Are Involved in the Transcriptional Regulation of Gonadotropin-Releasing Hormone (GnRH) Receptor by GnRH and Mitogen-Activated Protein Kinase Signal Transduction Pathway in GGH3 Cells Biol Reprod, August 1, 2001; 65(2): 561 - 567. [Abstract] [Full Text] [PDF]

				K. W. Cheng, B. K. C. Chow, and P. C. K. Leung Functional Mapping of a Placenta-Specific Upstream Promoter for Human Gonadotropin-Releasing Hormone Receptor Gene Endocrinology, April 1, 2001; 142(4): 1506 - 1516. [Abstract] [Full Text]

				H. Pincas, K. Amoyel, R. Counis, and J.-N. Laverrière Proximal cis-Acting Elements, Including Steroidogenic Factor 1, Mediate the Efficiency of a Distal Enhancer in the Promoter of the Rat Gonadotropin-Releasing Hormone Receptor Gene Mol. Endocrinol., February 1, 2001; 15(2): 319 - 337. [Abstract] [Full Text]

				K. W. Cheng, E. S. W. Ngan, S. K. Kang, B. K. C. Chow, and P. C. K. Leung Transcriptional Down-Regulation of Human Gonadotropin-Releasing Hormone (GnRH) Receptor Gene by GnRH: Role of Protein Kinase C and Activating Protein 1 Endocrinology, October 1, 2000; 141(10): 3611 - 3622. [Abstract] [Full Text] [PDF]

				R. C. X. Li, P. Ping, J. Zhang, W. B. Wead, X. Cao, J. Gao, Y. Zheng, S. Huang, J. Han, and R. Bolli PKCepsilon modulates NF-kappa B and AP-1 via mitogen-activated protein kinases in adult rabbit cardiomyocytes Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H1679 - H1689. [Abstract] [Full Text] [PDF]

				J. M. Mulvaney and M. S. Roberson Divergent Signaling Pathways Requiring Discrete Calcium Signals Mediate Concurrent Activation of Two Mitogen-activated Protein Kinases by Gonadotropin-releasing Hormone J. Biol. Chem., May 5, 2000; 275(19): 14182 - 14189. [Abstract] [Full Text] [PDF]

				R. Grosse, S. Roelle, A. Herrlich, J. Hohn, and T. Gudermann Epidermal Growth Factor Receptor Tyrosine Kinase Mediates Ras Activation by Gonadotropin-releasing Hormone J. Biol. Chem., April 14, 2000; 275(16): 12251 - 12260. [Abstract] [Full Text] [PDF]

				J. Weck, A. C. Anderson, S. Jenkins, P. C. Fallest, and M. A. Shupnik Divergent and Composite Gonadotropin-Releasing Hormone-Responsive Elements in the Rat Luteinizing Hormone Subunit Genes Mol. Endocrinol., April 1, 2000; 14(4): 472 - 485. [Abstract] [Full Text]

				D. L. Duval, A. R. Farris, C. C. Quirk, T. M. Nett, D. L. Hamernik, and C. M. Clay Responsiveness of the Ovine Gonadotropin-Releasing Hormone Receptor Gene to Estradiol and Gonadotropin-Releasing Hormone Is Not Detectable in Vitro But Is Revealed in Transgenic Mice Endocrinology, March 1, 2000; 141(3): 1001 - 1010. [Abstract] [Full Text] [PDF]

				J. M. Mulvaney, T. Zhang, C. Fewtrell, and M. S. Roberson Calcium Influx through L-type Channels Is Required for Selective Activation of Extracellular Signal-regulated Kinase by Gonadotropin-releasing Hormone J. Biol. Chem., October 15, 1999; 274(42): 29796 - 29804. [Abstract] [Full Text] [PDF]

				E. R. Norwitz, K.-H. Jeong, and W. W. Chin Molecular Mechanisms of Gonadotropin-Releasing Hormone Receptor Gene Regulation Reproductive Sciences, July 1, 1999; 6(4): 169 - 178. [Abstract] [PDF]

				S. C. Sharma and J. S. Richards Regulation of AP1 (Jun/Fos) Factor Expression and Activation in Ovarian Granulosa Cells. RELATION OF JunD AND Fra2 TO TERMINAL DIFFERENTIATION J. Biol. Chem., October 20, 2000; 275(43): 33718 - 33728. [Abstract] [Full Text] [PDF]

				A. M. Ionescu, E. M. Schwarz, C. Vinson, J. E. Puzas, R. Rosier, P. R. Reynolds, and R. J. O'Keefe PTHrP Modulates Chondrocyte Differentiation through AP-1 and CREB Signaling J. Biol. Chem., April 6, 2001; 276(15): 11639 - 11647. [Abstract] [Full Text] [PDF]

				H. Pincas, J.-N. Laverriere, and R. Counis Pituitary Adenylate Cyclase-activating Polypeptide and Cyclic Adenosine 3',5'-Monophosphate Stimulate the Promoter Activity of the Rat Gonadotropin-releasing Hormone Receptor Gene via a Bipartite Response Element in Gonadotrope-derived Cells J. Biol. Chem., June 22, 2001; 276(26): 23562 - 23571. [Abstract] [Full Text] [PDF]