Thyrotropin (TSH) is the pituitary glycoprotein hormone which controls the growth and function of the thyroid gland. It is produced solely by thyrotrope cells, one of five terminally differentiated pituitary cell types. The TSH molecule is composed of two nonidentical glycosylated subunits, alpha and TSHbeta, which are noncovalently associated. These two subunits arise independently from separate genes located on different chromosomes. The alpha-subunit gene is expressed not only in TSH cells but also pituitary gonadotropes and placental chorionic gonadotropes. In contrast, TSH-beta gene expression is restricted only to thyrotropes. The studies outlined in this grant proposal are firmly based on previous studies from this laboratory in which the gene for the murine TSH-beta subunit has been isolated and sequenced, its promoter-region characterized, the important functional cis-acting DNA elements identified, and the putative areas of protein-DNA interactions on the promoter determined. Our proposed investigations will be to first define the DNA sequences contained in the functionally most important footprint of the TSH-beta promoter which are responsible for thyrotrope-specific expression of this gene. We will then analyze the role of our newly discovered thyrotrope-specific variant isoform of the Pit-1 protein. The studies are designed to understand precisely the role of this novel factor on TSH-beta promoter activation. We will then attempt to reconstitute TSH- beta promoter activation in stably transfected cells with the unique Pit-1 isoforms. For these studies, we will utilize another unique reagent developed in this laboratory, an isogenic alpha-TSH cell line which has lost the ability to express the TSH-beta subunit gene. Finally, we will utilize our precise understanding of the cis-acting determinants of the TSH-beta promoter to identify and clone other novel DNA-binding factors in thyrotrope cells which activate the TSH-beta promoter. These projects will utilize the most modern techniques of cell biology and molecular endocrinology. Recombinant DNA technology will be coupled with novel methods analyzing gene expression in unique cell lines. These studies will provide fundamental information on pituitary cell differentiation and cell-specific gene expression which is directly applicable to human thyroid-pituitary disease.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Endocrinology Study Section (END)
Program Officer
Linder, Barbara
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Colorado Denver
Internal Medicine/Medicine
Schools of Medicine
United States
Zip Code
Charles, Michael A; Saunders, Thomas L; Wood, William M et al. (2006) Pituitary-specific Gata2 knockout: effects on gonadotrope and thyrotrope function. Mol Endocrinol 20:1366-77
Christoffolete, Marcelo A; Ribeiro, Rogerio; Singru, Praful et al. (2006) Atypical expression of type 2 iodothyronine deiodinase in thyrotrophs explains the thyroxine-mediated pituitary thyrotropin feedback mechanism. Endocrinology 147:1735-43
Gordon, David F; Tucker, Elizabeth A; Tundwal, Kavita et al. (2006) MED220/thyroid receptor-associated protein 220 functions as a transcriptional coactivator with Pit-1 and GATA-2 on the thyrotropin-beta promoter in thyrotropes. Mol Endocrinol 20:1073-89
Sarapura, Virginia D; Wood, William M; Woodmansee, Whitney W et al. (2006) Pituitary tumors arising from glycoprotein hormone alpha-subunit-deficient mice contain transcription factors and receptors present in thyrotropes. Pituitary 9:11-8
Woodmansee, Whitney W; Kerr, Janice M; Tucker, Elizabeth A et al. (2006) The proliferative status of thyrotropes is dependent on modulation of specific cell cycle regulators by thyroid hormone. Endocrinology 147:272-82
McDermott, Michael T; Haugen, Bryan R; Black, Jennifer N et al. (2002) Congenital isolated central hypothyroidism caused by a ""hot spot"" mutation in the thyrotropin-beta gene. Thyroid 12:1141-6
Gordon, David F; Woodmansee, Whitney W; Black, Jennifer N et al. (2002) Domains of Pit-1 required for transcriptional synergy with GATA-2 on the TSH beta gene. Mol Cell Endocrinol 196:53-66
Wood, William M; Sarapura, Virginia D; Dowding, Janet M et al. (2002) Early gene expression changes preceding thyroid hormone-induced involution of a thyrotrope tumor. Endocrinology 143:347-59
Brinkmeier, M L; Stahl, J H; Gordon, D F et al. (2001) Thyroid hormone-responsive pituitary hyperplasia independent of somatostatin receptor 2. Mol Endocrinol 15:2129-36
Woodmansee, W W; Gordon, D F; Dowding, J M et al. (2000) The effect of thyroid hormone and a long-acting somatostatin analogue on TtT-97 murine thyrotropic tumors. Thyroid 10:533-41

Showing the most recent 10 out of 43 publications