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

ANGELETTI SOFÍA; NORES RODRIGO; RENA VIVIANA; GENTI DE RAIMONDI SUSANA

Santiago de Chile

Simposio; II Latin-american symposium materno-fetal interaction & placenta: from basic to clinical research.; 2005

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 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 synctytialize with methotrexate. Results: A 35 kDa protein was detected in JEG-3 and HTR8/SVNeo cell lines; placenta of first and third trimester; choriocarcinoma; and cyto and syncitiotrophoblast cells. Furthermore, an increase in StarD7 expression was observed in JEG-3 cells exposed to methotrexate. Conclusions: Our findings suggest that StarD7 may play a functional role in the process of trophoblast differentiation throught phospholipids uptake and transport.