ORBi: Jacquemin P. - The enhancers of the human placental lactogen B, A, and L genes: progressive activation during in vitro trophoblast differentiation and importance of the DF-3 element in determining their respective activities

Reference : The enhancers of the human placental lactogen B, A, and L genes: progressive activation ...


	Document type :	Scientific journals : Article
	Discipline(s) :	Life sciences : Biochemistry, biophysics & molecular biology
	To cite this reference:	http://hdl.handle.net/2268/19834

Title :	The enhancers of the human placental lactogen B, A, and L genes: progressive activation during in vitro trophoblast differentiation and importance of the DF-3 element in determining their respective activities
Language :	English
Author, co-author :	Jacquemin, P. [> > > >]
	Alsat, E. [> > > >]
	Oury, Cécile [Université de Liège - ULg > Département des sciences biomédicales et précliniques > GIGA-R : Génétique générale et humaine >]
	Belayew, A. [> > > >]
	Muller, Marc [Université de Liège - ULg > Département des sciences de la vie > GIGA-R : Biologie et génétique moléculaire >]
	Evain-Brion, D. [> > > >]
	Martial, Joseph [Université de Liège - ULg > Département des sciences de la vie > GIGA-R : Biologie et génétique moléculaire >]
Publication date :	1996
Journal title :	DNA & Cell Biology
Publisher :	Mary Ann Liebert, Inc.
Volume :	15
Issue/season :	10
Pages :	845-54
Audience :	International
ISSN :	1044-5498
e-ISSN :	1557-7430
City :	Larchmont
Country :	NY
Keywords :	[en] Base Sequence ; Cell Differentiation ; Cell Line ; Cells, Cultured ; Chloramphenicol O-Acetyltransferase/biosynthesis ; Chromosomes, Human, Pair 17 ; Enhancer Elements, Genetic ; Female ; Gene Expression Regulation ; Humans ; Mutagenesis ; Placenta/cytology ; Placental Lactogen/biosynthesis/genetics ; Polymerase Chain Reaction ; Pregnancy ; Recombinant Fusion Proteins/biosynthesis ; Sequence Homology, Nucleic Acid ; Thymidine Kinase/biosynthesis ; Transcription, Genetic ; Transfection ; Trophoblasts/cytology/*physiology
Abstract :	[en] The hCS-A and hCS-B genes encoding human chorionic somatomammotropin and the related hCS-L gene are very similar in their coding and flanking sequences. For each of these genes, downstream enhancers, varying in strength, have been identified with the help of cytotrophoblast-derived JEG-3 cells, which do not express the hCS genes. Here we study the activity of the hCS enhancers in human syncytiotrophoblast in primary culture, which naturally expresses the hCS genes. We show that the activity of the hCS-B gene enhancer is mediated by two elements, DF-3 and DF-4, whereas the hCS-L and hCS-A gene enhancers display weaker activity due to mutations in their respective DF-3 sites. Replacement of the hCS-B DF-3 site with the homologous hCS-A sequence causes hCS-B enhancer activity to decrease. Primary cytotrophoblasts differentiate in culture to form the syncytiotrophoblast. We show that during this process the production of hCS progressively increases and that concomitantly all three hCS enhancers are progressively activated. A targeted mutation in the 3' part of the DF-4 element abolishes the binding of a protein present only in syncytiotrophoblast extracts and inactivates the DF-4 element. Thus, a direct correlation exists between the appearance of this syncytiotrophoblast-specific protein and hCS enhancer activity. This primary culture model proves useful in studying the regulation of the hCS genes.
Permalink :	http://hdl.handle.net/2268/19834
Mentions required by the publisher for OA :	1996/10/01

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