We have previously reported the cloning and characterization of a novel gene up-regulated in the choriocarcinoma JEG-3 cell line. This gene, denominated StarD7, encodes a protein that belongs to the StAR-related lipid transfer proteins involved in intracellular lipid transport pathways. In addition, we demonstrated that purified overexpressed StarD7 protein interacts differentially with phospholipid monolayers. To initiate studies of the cis- and trans-acting factors that are important for transcriptional regulation of StarD7 gene expression, we isolated the human StarD7 gene promoter from genomic DNA by PCR amplification. Transcriptional activity of several 5´-flanking regions of the StarD7 promoter driving the expression of the luciferase reporter gen was analyzed in Cos-7 and JEG-3 cells by transient transfection assays. Promoter activity was observed in different constructs containing from nt +157 up to nt -1525 of the genomic StarD7 sequence. The 5´regulatory region containing from nt -121 to nt -673 activated StarD7 and SV40 promoter transcription in JEG-3 cells. Instead, the construct nt -1525 to nt -673 repressed both promoters. Taken together, these data suggest that transcriptional positive and negative regulatory factors present in JEG-3 cells could specifically regulate StarD7 promoter by interacting with the regions previously mentioned.
Supported by CONICET, FONCyT and SECyT-UNC
