1: Mol Hum Reprod. 2002 Mar;8(3):262-70. 

Control of the human inhibin alpha chain promoter in cytotrophoblast cells
differentiating into syncytium.

Debieve F, Thomas K.

Department of Obstetrics and Gynaecological Endocrinology, Universite Catholique
de Louvain, Brussels, Belgium. debieve@obst.ucl.ac.be

Inhibins are dimeric proteins consisting of a common alpha subunit linked to one
of the beta subunits, beta A or beta B. During pregnancy, the placenta is the
main source of inhibin A production and the in-vitro transformation of
cytotrophoblast cells into syncytium is associated with an inhibin alpha subunit
mRNA up-regulation. In this study, the 5' region of the human inhibin alpha gene
was isolated and sequenced. Three transcription initiation sites were
identified. When transiently transfected in trophoblast cells with a luciferase
reporter vector, the sequence displayed promoter activity. DNase I footprinting
and electrophoretic mobility shift assay (EMSA) analysis showed a specific
DNA-protein interaction in the promoter when using cytotrophoblast nuclear
proteins. This interaction was weaker with syncytiotrophoblast nuclear proteins.
Moreover, the deletion of this DNA-protein interaction region suppressed the
promoter activity. In an attempt to identify this factor, the potential binding
of known factors delta EF1, AP1 and NFE2 were excluded by competition EMSA
experiments. We suggest that it may correspond to an undescribed protein
interaction. The identification of the human inhibin alpha promoter could help
in understanding the mechanisms modulating inhibin gene transcription. Moreover,
the identification of a factor, whose presence is related to the trophoblast
cell differentiation state, could help in understanding the transformation of
cytotrophoblast cells into syncytium.

PMID: 11870234 [PubMed - indexed for MEDLINE]


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