Syncytiotrophoblast differentiation is associated with transcriptional activation of genes belonging to the pregnancy-specific glycoprotein gene family

CAMOLOTTO S.; RACCA A.; RENA V.; PATRITO L; GENTI-RAIMONDI S; PANZETTA-DUTARI G.

Los Cocos. Argentina

Simposio; III Latin-American Symposium on Maternal-Fetal Interaction & Placenta: Basic and clinical research; 2007

Latin American Placenta group

The eleven human pregnancy-specific glycoprotein (PSG) genes are tightly linked within

Ch 19q13.2. They are highly similar, have the same transcriptional orientation and are

essential for maintenance of gestation. PSG mRNAs and proteins are markedly induced

during trophoblast differentiation. However, little is known about the transcriptional

control and expression pattern of each PSG gene. Objectives: This report examines

the expression level and transcriptional activation of five PSG genes during in vitro syncytialization

of human trophoblast cells. Methods: Normal villous cytotrophoblast and

Jeg3 cells were induced to differentiate into syncytium- like structures. RNA isolated

at different times was analyzed by semi-quantitative RT-PCR using PSG transcript specific

primers. Transient transfection assays of PSG promoters:LUC constructs were performed.

Results: PSG expression of all analyzed transcripts increased during

differentiation. PSG3, 5 and 7 promoter constructs bearing up to 600 pb of the 5 ´ proximal

regulatory region revealed different basal promoter activities which were increased upon

differentiation. In addition, treatment of Jeg3 cells with chromatin modifying reagents induced

increased transcription of endogenous PSG genes. Conclusions: Our results suggest

that transcription of all PSG family members are activated during trophoblast

differentiation. This activation involves regulatory elements present within the 5 ´ proximal

regulatory region, as well as, chromatin modifications. Supported by CONICET,

FONCYT and SECyT UNC.