Reproduction depends on production of LH and FSH from the pituitary and CG from the placenta. Expression of the genes encoding these gonadotropins occurs in a strict temporal and spatial sequence. Any insult that perturbs their expression has dire consequences on reproductive fitness. Based on our previous work, we postulate that three levels of combinatorial code are used to direct appropriate temporal and spatial expression of gonadotropin genes. The first involves formation of a cell-specific composite regulatory element from a larger menu of many regulatory elements. The second level occurs through selection of one of many transcription factors that can bind a given element. Finally, the third code utilizes specific co-adapters that link the required DNA-binding proteins to the core transcription complex.
The aims below differ from the previous funding period because we turn from cis-acting elements that comprise the first level of code to the second and third tiers that include both DNA-binding proteins and proteins that bind to them.
Aims 1 and 2, we will use the glycoprotein hormone alpha subunit gene (alphaGSU) as a model for understanding how a single gene can be targeted for expression to two cell types that do not share a common lineage and are spatially distinct. Emphasis will be placed on addressing whether specific members of the basic leucine zipper family (BZIP) play critical roles in defining the site of alpha gene expression. We will also examine other transcription factors and determine how their targeted reduction affects expression of alpha and other genes expressed in trophoblasts and gonadotropes.
In Aim 3, we focus on the LHbeta gene and use both transfection and transgenic approaches to define elements that are both necessary and sufficient for gonadotrope-specific expression in vivo. In addition, we will use transgenic mice to explore the importance of specific transcription factors to gonadotrope health in vivo. Pursuit of these aims will involve a variety of approaches including: cloning of new transcriptional factors; transient transfection paradigms with dominant negative constructs that prevent occupancy of a target cis-acting elements; construction of stable """"""""knockdown"""""""" cell lines that lack specific trans-acting factors; and ultimate validation of physiological significance with transgenic mice that harbor dominant-negative genes targeted to gonadotropes. In essence, we intend to establish a hierarchy of genes that define functional properties of trophoblasts and gonadotropes. Such knowledge will spawn development of new therapeutic tools that include both agents and targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK028559-21
Application #
6380444
Study Section
Biochemical Endocrinology Study Section (BCE)
Program Officer
Sato, Sheryl M
Project Start
1980-09-01
Project End
2004-08-31
Budget Start
2001-09-01
Budget End
2002-08-31
Support Year
21
Fiscal Year
2001
Total Cost
$362,295
Indirect Cost
Name
Case Western Reserve University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Salisbury, Travis B; Binder, April K; Grammer, Jean C et al. (2007) Maximal activity of the luteinizing hormone beta-subunit gene requires beta-catenin. Mol Endocrinol 21:963-71
Jorgensen, Joan S; Quirk, Christine C; Nilson, John H (2004) Multiple and overlapping combinatorial codes orchestrate hormonal responsiveness and dictate cell-specific expression of the genes encoding luteinizing hormone. Endocr Rev 25:521-42
Quirk, Christine C; Seachrist, Darcie D; Nilson, John H (2003) Embryonic expression of the luteinizing hormone beta gene appears to be coupled to the transient appearance of p8, a high mobility group-related transcription factor. J Biol Chem 278:1680-5
Mohammad, Helai P; Abbud, Rula A; Parlow, Al F et al. (2003) Targeted overexpression of luteinizing hormone causes ovary-dependent functional adenomas restricted to cells of the Pit-1 lineage. Endocrinology 144:4626-36
Jorgensen, J S; Nilson, J H (2001) AR suppresses transcription of the LHbeta subunit by interacting with steroidogenic factor-1. Mol Endocrinol 15:1505-16
Jorgensen, J S; Nilson, J H (2001) AR suppresses transcription of the alpha glycoprotein hormone subunit gene through protein-protein interactions with cJun and activation transcription factor 2. Mol Endocrinol 15:1496-504
Quirk, C C; Lozada, K L; Keri, R A et al. (2001) A single Pitx1 binding site is essential for activity of the LHbeta promoter in transgenic mice. Mol Endocrinol 15:734-46
Keri, R A; Bachmann, D J; Behrooz, A et al. (2000) An NF-Y binding site is important for basal, but not gonadotropin-releasing hormone-stimulated, expression of the luteinizing hormone beta subunit gene. J Biol Chem 275:13082-8
Abbud, R A; Ameduri, R K; Rao, J S et al. (1999) Chronic hypersecretion of luteinizing hormone in transgenic mice selectively alters responsiveness of the alpha-subunit gene to gonadotropin-releasing hormone and estrogens. Mol Endocrinol 13:1449-59
Budworth, P R; Quinn, P G; Nilson, J H (1997) Multiple characteristics of a pentameric regulatory array endow the human alpha-subunit glycoprotein hormone promoter with trophoblast specificity and maximal activity. Mol Endocrinol 11:1669-80

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