Transcriptional regulation of the StarD7 gene by steroidogenic factor 1

RENA VIVIANA; ANGELETTI SOFÍA; PANZETTA DE DUTARI GRACIELA M; GENTI-RAIMONDI SUSANA

Rosario Argentina

Congreso; XLII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

SAIB

We have previously cloned and characterized a novel gene upregulated in choriocarcinoma JEG-3 cell line. This gene, denominated StarD7 encodes a protein that belongs to the StARrelated lipids transfer proteins involved in intracellular transport and metabolism of lipids. To understand the molecular mechanisms that regulate the expression of StarD7 gene, we have cloned and characterized the 5´flanking region of the gene. Transient transfections of several 5´deleted StarD7-promoterfirefly luciferase constructs into JEG-3 and COS-7 cells suggest that the -312/+157 region contains the gene minimal promoter. In addition, sequence analysis of a 1,6 kb gene fragment revealed the presence of a TATA-less promoter as well as multiple regulatory motifs, including one steroidogenic factor 1 (SF-1) binding site at -796/-784 and three cAMP-responsive binding elements at -512/-509, -465/-462 and -115/-111. Electrophoretic mobility shift assays using nuclear proteins from JEG-3 show DNA-protein specific complexes. Co-transfection experiments of JEG-3 and COS-7 cell lines demonstrated that the human StarD7 promoter is activated by SF-1 transcription factor and this effect is increased by cAMP. These studies provide novel insights into the regulation of the human StarD7 gene at the transcriptional level by SF-1.