Growth hormone (GH) is a powerful regulator of linear growth and metabolic homeostasis that acts at almost all organ systems. Exogenous GH therapy is costly but effective at counteracting the profound metabolic effects associated with idiopathic GH-deficiency and, seemingly, the normal age-related decline in GH gene transcription. GH synthesis is restricted to the somatotroph cells of the anterior pituitary gland where the transcription of the GH gene is tightly regulated in distinct physiologic, age-related and circadian patterns by systemic and hypothalamic hormones, many of which operate via protein kinase systems. Our long-term goal is to identify the molecular mechanisms of hormone- regulated, somatotroph-specific GH gene expression as a first step in the design of cost-effective therapies targeting GH transcription. The transcription factor C/EBPalpha cooperates with the pituitary-specific transcription factor Pit-1 and the coactivator CBP to control protein kinase A and C-regulated GH gene transcription. Cooperative activation likely arises from mutual or complementary, kinase-regulated actions of C/EBPalpha, Pit-1 and CBP at specific basal factor and/or structural targets. C/EBPalpha, Pit-1 and CBP each interact with, and colocalize to a nuclear substructure with, the basal transcription factor TBP that participates in activation by those transcription factors and cofactor. The molecular basis for cooperative action will be assessed by examining C/EBPalpha, CBP, Pit-1, and TBP activities required for kinase-regulated GH promoter activation by, nuclear localization of, and physical interactions between, those factors. We have already developed a series of innovative in vivo cellular assays which will allow us to determine the: 1. structures in C/EBPalpha and CBP affecting kinase-regulated cooperative activation of the GH promoter, 2. structures in TBP required for kinase-regulated C/EBPalpha, CBP and Pit-1 GH promoter activation, 3. nuclear positioning of C/EBPalpha, CBP, Pit-1, TBP and TFIIB and the spatiotemporal relationships of interactions between those factors under the same cellular conditions used in the functional assays. 4. the role of C/EBPalpha in the embryonic onset of GH gene transcription in C/EBPalpha knockout mice which die shortly after birth.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK054345-03
Application #
6381203
Study Section
Biochemical Endocrinology Study Section (BCE)
Program Officer
Sato, Sheryl M
Project Start
1999-07-01
Project End
2003-06-30
Budget Start
2001-07-01
Budget End
2003-06-30
Support Year
3
Fiscal Year
2001
Total Cost
$227,420
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Kofoed, Eric M; Guerbadot, Martin; Schaufele, Fred (2010) Structure, affinity, and availability of estrogen receptor complexes in the cellular environment. J Biol Chem 285:2428-37
Kofoed, Eric M; Guerbadot, Martin; Schaufele, Fred (2008) Dimerization between aequorea fluorescent proteins does not affect interaction between tagged estrogen receptors in living cells. J Biomed Opt 13:031207
Liu, Xiaowei; Wu, Bo; Szary, Jaroslaw et al. (2007) Functional sequestration of transcription factor activity by repetitive DNA. J Biol Chem 282:20868-76
Day, Richard N; Schaufele, Fred (2005) Imaging molecular interactions in living cells. Mol Endocrinol 19:1675-86
Ross, Sarah E; Radomska, Hanna S; Wu, Bo et al. (2004) Phosphorylation of C/EBPalpha inhibits granulopoiesis. Mol Cell Biol 24:675-86
Enwright 3rd, John F; Kawecki-Crook, Margaret A; Voss, Ty C et al. (2003) A PIT-1 homeodomain mutant blocks the intranuclear recruitment of the CCAAT/enhancer binding protein alpha required for prolactin gene transcription. Mol Endocrinol 17:209-22
Schaufele, Fred; Wang, Xia; Liu, Xiaowei et al. (2003) Conformation of CCAAT/enhancer-binding protein alpha dimers varies with intranuclear location in living cells. J Biol Chem 278:10578-87
Day, Richard N; Voss, Ty C; Enwright 3rd, John F et al. (2003) Imaging the localized protein interactions between Pit-1 and the CCAAT/enhancer binding protein alpha in the living pituitary cell nucleus. Mol Endocrinol 17:333-45
Weatherman, R V; Chang, C-Y; Clegg, N J et al. (2002) Ligand-selective interactions of ER detected in living cells by fluorescence resonance energy transfer. Mol Endocrinol 16:487-96
Liu, Weiqun; Enwright 3rd, John F; Hyun, William et al. (2002) CCAAT/enhancer binding protein alpha uses distinct domains to prolong pituitary cells in the growth 1 and DNA synthesis phases of the cell cycle. BMC Cell Biol 3:6

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