Human (h) growth hormone (GH), chorionic somatomammotropin (CS) and prolactin (PRL) comprise a family of genes that are essential for normal human growth and development. Altered GH production has been implicated in various pathological states, including osteoporosis and aging. Knowledge of the regulation of these genes is important for our understanding of their physiologic and pathophysiologic functions. The proposed studies extend previous investigations on the hormonal and tissue-specific factors that mediate transcript ion of hGH/hCS genes.
Aim 1 focuses on the functional significance of DNA bending induced by the thyroid hormone receptor (TR), cell-specific factor GHF1 and Sp1. The contributions of intrinsic and transcription factor-induced DNA bending will be established by circular permutation and phasing analyses. The influence of DNA phasing-induced changes on overall promoter conformation will be correlated with promoter activities using transient transfection assays and in vitro transcription systems. TR mutants that exhibit coupled and uncoupled DNA binding and transcriptional activation responses will be examined by bending analyses to determine whether DNA bending is coupled to DNA binding or transactivation functions.
Aim 2 will examine the structure and mechanism of action of a unique, promoter-dependent negative thyroid hormone response element (nTRE) located in the 3'-flanking DNA of the hGH gene. The precise structure of the nTRE will be established utilizing mutagenesis and analysis of functional activity with transfection assays. The hGH promoter elements that are required for nTRE function will be established by mutagenesis of the hGH 5'-flanking region/promoter and functional analysis using transient transfection assays. The mechanism of nTRE action will be examined by a combination of run-on transcription, in vitro transcription and in vitro polyadenylation and/or splicing experiments to establish whether nTRE action is coupled to transcript ion initiation, elongation or termination/3'-end formation. The physiologic relevance of nTRE function on hGH gene expression will be examined by the ongoing studies of human acromegalic tumor cells. These studies will extend our understanding of the factors that regulate the hormonal and tissue-specific regulation of hGH/hCS gene expression.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK041206-08
Application #
2141635
Study Section
Endocrinology Study Section (END)
Project Start
1989-07-01
Project End
1998-06-30
Budget Start
1995-07-01
Budget End
1996-06-30
Support Year
8
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
City
Rochester
State
MN
Country
United States
Zip Code
55905
Trujillo, Miguel A; Sakagashira, Michiko; Eberhardt, Norman L (2006) The human growth hormone gene contains a silencer embedded within an Alu repeat in the 3'-flanking region. Mol Endocrinol 20:2559-75
Trujillo, Miguel A; Jiang, Shi-Wen; Tarara, James E et al. (2003) Clustering of the B cell receptor is not required for the apoptotic response. DNA Cell Biol 22:513-23
Trujillo, Miguel A; Eberhardt, Norman L (2003) Kinetics of the apoptotic response induced by anti-IgM engagement of the B cell receptor is dependent on the density of cell surface immunoglobulin M expression. DNA Cell Biol 22:525-31
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Jiang, S W; Wu, K; Eberhardt, N L (1999) Human placental TEF-5 transactivates the human chorionic somatomammotropin gene enhancer. Mol Endocrinol 13:879-89
Jiang, S W; Eberhardt, N L (1997) The human chorionic somatomammotropin enhancers form a composite silencer in pituitary cells in vitro. Mol Endocrinol 11:1233-44
Jiang, S W; Trujillo, M A; Eberhardt, N L (1997) Human chorionic somatomammotropin enhancer function is mediated by cooperative binding of TEF-1 and CSEF-1 to multiple, low-affinity binding sites. Mol Endocrinol 11:1223-32
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Jiang, S W; Eberhardt, N L (1996) TEF-1 transrepression in BeWo cells is mediated through interactions with the TATA-binding protein, TBP. J Biol Chem 271:9510-8
Eberhardt, N L; Jiang, S W; Shepard, A R et al. (1996) Hormonal and cell-specific regulation of the human growth hormone and chorionic somatomammotropin genes. Prog Nucleic Acid Res Mol Biol 54:127-63

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