We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Molecular aspects of pregnancy. Cyclic AMP- and differentiation-dependent regulation of the proximal gene promoter in term villous trophoblasts.
- Authors
Knöfler, Martin; Saleh, Leila; Strohmer, Heinz; Husslein, Peter; Wolschek, Markus F.
- Abstract
Although the regulatory mechanisms controlling α and β human chorionic gonadotrophin (HCG) expression have been investigated in choriocarcinoma cell model systems, little is known about the regulation of HCG subunit synthesis in non-tumourigenic trophoblasts. We therefore investigated αHCG mRNA transcription in villous cytotrophoblasts isolated from term placentae and have shown for the first time that the proximal αHCG gene promoter is functional in these cells. By establishing conditions which allow efficient transient transfection of immunopurified cells, we have demonstrated that a 363 bp sequence in the proximal 5′ flanking region of the αHCG gene is sufficient to direct trophoblast-specific expression of a luciferase reporter. After 12-60 h cultivation, an increase in endogenous αHCG mRNA expression could be detected, indicating that aggregated villous trophoblasts undergo biochemical differentiation. Concomitantly, we observed induction of αHCG promoter-driven luciferase activity, suggesting that the 363 bp sequence of the proximal 5′ flanking region is sufficient to direct differentiation-dependent increase of αHCG mRNA. Continuous luciferase expression required functional cAMP-response elements (CREs), since deletion of both recognition sequences eliminated differentiation-dependent transcription of the reporter. Elevation of cAMP values increased transcription of the wild-type construct; however, it did not affect promoter activity of the mutant plasmid. Moreover, we have demonstrated that during in-vitro differentiation, CREs interacted with increasing amounts of phosphorylated activating transcription factor/cyclic AMP response element-binding protein (ATF-1/CREB-1) suggesting that these cAMP-dependent DNA-binding factors are major determinants in regulating αHCG gene expression in villous trophoblasts.
- Subjects
CHORIONIC gonadotropins; TROPHOBLAST
- Publication
Molecular Human Reproduction, 1999, Vol 5, Issue 6, p573
- ISSN
1360-9947
- Publication type
Article
- DOI
10.1093/molehr/5.6.573