Transcriptional Control of the Human Pregnancy-Specific Glycoprotein 5 Gene Is Dependent on Two GT-Boxes Recognized by the Ubiquitous Specificity Protein 1 (Sp1) Transcription Factor

NORES, R.; BLANCHON, L.; LÓPEZ-DÍAZ, F.; BOCCO, J.L.; PATRITO, L.C.; SAPIN, V.; PANZETTA-DUTARI, G.

Embu das Artes, San Pablo

Simposio; Ist Latin-American Symposium on Maternal-Fetal Interaction - Placenta: Clinical & Research (I-SLIMP); 2003

Sociedad Latinoamericana de Investigaciones Materno-Fetales y Placentarias

Pregnancy-specific glycoprotein 5 (PSG5) gene belongs to the human pregnancy-specific glycoprotein family, which is encoded by eleven highly similar and transcriptionally active genes. High levels of PSG biosynthesis are restricted to the placenta syncytiotrophoblast and are essential for the maintenance of normal gestation in mammalian species. To get further insight into the regulatory factors involved in PSG5 gene expression, we have investigated the nature of the transcription factors that recognize similar GT-box motifs present in FP1 (-455/-433) and CPE (-147/-140) regulatory sequences. Gel shift, super gel shift and UV-crosslinking experiments clearly demonstrate that the ubiquitous Sp1 protein is the major transcription factor involved in complex formation with both cis-acting elements in normal term placenta and in PSG-non-expressing COS7 cells. Furthermore, transfection experiments indicate that Sp1 activates PSG5 promoter constructs in COS7 and SL2 cell lines. In addition, Sp1 is co-expressed with PSG genes in the syncytiotrophoblast cells, stressing its potential role in the in vivo regulation of PSG expression.