Chorionic gonadotropin (CG) is a key luteotropic hormone secreted by the developing conceptus in primates. Endocrine mechanisms contributing to maximal CG subunit synthesis are important determinants of a successful pregnancy. Preliminary evidence suggests that the CG alpha subunit gene is synergistically induced in a placental-specific manner via a complex transcriptional """"""""unit"""""""" comprised of several cis elements (two CREs and the JRE) necessary for integration of multiple intracellular signals. The CRE binding complex consists of several activator (CREB, AP-1, CBP) and corepressor molecules (HDAC2). The JRE is a homeobox-binding site that interacts with Distal-less 3 (D1x3). This proposal details a complex series of experiments examining the hypothesis that transcriptional activators and repressors contribute combinatorially to the cell-specific regulation of the alpha subunit gene. Further, trophoblast differentiation depends upon gene programs induced by Dlx3. The overall goal is a comprehensive understanding of mechanisms governing CG synthesis and analysis of factors regulating trophoblast differentiation.
The aims are:
Aim 1 : Continued analysis of the mechanisms that govern CRE-dependent alpha subunit gene regulation in trophoblasts. CRE-dependent alpha subunit gene regulation and the effects of the EGF and cAMP will be examined in primary human trophoblasts. Biochemical and mutagenesis studies investigate the role of coregulators within the CRE binding complex and defines the extent of chromatin remodeling within the alpha subunit promoter.
Aim 2 : Explore the role of Dlx3 in the regulation of the alpha subunit gene. Studies will analyze the Dlx3 expression pattern in primate placenta and during trophoblast differentiation in vitro by immunocytochemistry. Biochemical and mutagenesis studies will examine interactions between CRE and JRE binding complexes within the alpha subunit promoter. Interacting partners of Dlx3 that contribute to alpha subunit gene regulation and to trophoblast differentiation will be identified.
Aim 3 : Examine the role of Dlx3 in placental development and differentiation. The Dlx3 knockout mouse will be used to identify gene programs induced by Dlx3 in murine trophoblasts using state-of-the-art gene profiling analysis. To complement these studies, an investigation of the factors required to mediate transcriptional activation of the Dlx3 gene promoter that will lead to identification of """"""""upstream"""""""" effectors of trophoblast differentiation will be conducted.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
1R01HD039354-01A2
Application #
6431063
Study Section
Biochemical Endocrinology Study Section (BCE)
Program Officer
Yoshinaga, Koji
Project Start
2002-02-20
Project End
2007-01-31
Budget Start
2002-02-20
Budget End
2003-01-31
Support Year
1
Fiscal Year
2002
Total Cost
$282,194
Indirect Cost
Name
Cornell University
Department
Other Basic Sciences
Type
Schools of Veterinary Medicine
DUNS #
City
Ithaca
State
NY
Country
United States
Zip Code
14850
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Berghorn, Kathie A; Clark-Campbell, Patricia A; Han, Li et al. (2006) Smad6 represses Dlx3 transcriptional activity through inhibition of DNA binding. J Biol Chem 281:20357-67
Berghorn, K A; Clark, P A; Encarnacion, B et al. (2005) Developmental expression of the homeobox protein Distal-less 3 and its relationship to progesterone production in mouse placenta. J Endocrinol 186:315-23
Tyner, Katherine M; Roberson, Mark S; Berghorn, Kathie A et al. (2004) Intercalation, delivery, and expression of the gene encoding green fluorescence protein utilizing nanobiohybrids. J Control Release 100:399-409
Holland, Manja P; Bliss, Stuart P; Berghorn, Kathie A et al. (2004) A role for CCAAT/enhancer-binding protein beta in the basal regulation of the distal-less 3 gene promoter in placental cells. Endocrinology 145:1096-105