Functional characterization of StarD7, a novel gestational tumor START domain containing-protein

S. ANGELETTI; R. NORES; V. RENA; S. GENTI-RAIMONDI

Santiago

Simposio; II Latin-American Symposium on Fetal-Maternal Interaction and Placenta: From Basic to Clinical Research (II-SLIMP) and XIX Annual Meeting of the Chilean Society of Physiological Sciences; 2005

Chilean Society of Physiological Sciences

In a previous work, we identified the StarD7 transcript, up-regulated in choriocarcinoma JEG-3 cell line. This transcript encodes one of the 15 family members with START domain present in the human genome, implicated in lipid/sterol binding. In addition, we demonstrated that StarD7 recombinant protein interacts differentially with phospholipids monolayers. The purpose of this study was to determine the role of this novel protein in the physiology of the cell. Methods: Western blot and immunofluorescence assays were performed with two different antibodies obtained against overexpressed StarD7 and StarD7-C-terminal amino acids. Besides, StarD7 expression was analyzed in JEG-3 cultures exposed to syncytialize with methotrexate. Results: A 35 kDa protein was detected in JEG-3 and HTR-8/SVNeo cell lines; placenta of first and third trimester; choriocarcinoma; and cyto, and syncytiotrophoblast cells. In addition, it was demonstrated that StarD7 protein is localized mainly in the cytoplasm. Furthermore, an increase in StarD7 expression was observed in JEG-3 cells exposed to methotrexate. Conclusions: Our findings suggest that StarD7 could play a functional role in the process of trophoblast differentiation through phospholipids uptake and transport. Supported by FONCyT and SECyT-UNC.