The primate syncytiotrophoblast expresses placental growth hormone- variant and chorionic somatomammotropin members of the growth hormone gene locus. The genetic mechanisms which underlie placenta-specific expression of these hormones remain poorly understood. To define these mechanisms in vitro, the regulation of monkey placental growth hormone- variant (mGH-V) transcription by cAMP (an important determinant of trophoblast hormone gene expression) will be studied during cytotrophoblast to syncytiotrophoblast differentiation in primary cultures. We hypothesize that cAMP stimulation and trophoblast differentiation induce or activate placenta-specific DNA-binding proteins or co-activators. Novel elements mediating transcription- activating effects of cAMP will be identified by block mutagenesis of the proximal (-140 to -66 bp) 5'-flanking DNA of-the mGH-V gene, shown to confer basal and cAMP-sensitive/placenta-specific transcriptional activity. Transcription factors which interact with these elements will be characterized by gel mobility-shift assays, uv cross-linking analyses and affinity chromatography. These transcription factors will be cloned by screening placental syncytiotrophoblast cDNA expression libraries with mGH-V regulatory element DNA probes, by using a yeast hybrid approach to screen for interacting proteins, or by differential display analysis to identify placenta-specific and cAMP-induced mRNAs. Additional distal enhancers will be located in upstream 5' and 3'- flanking gene regions. These studies will provide direct information on how transcription factors and their expression underlie the cell- specific and developmentally regulated expression of placental hormone genes at the maternal-fetal interface during trophoblast differentiation.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD026458-09
Application #
2673604
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Project Start
1989-12-01
Project End
2000-03-31
Budget Start
1998-04-01
Budget End
1999-03-31
Support Year
9
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Veterinary Sciences
Type
Other Domestic Higher Education
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715