Molecular analysis of the prostate-specific antigen upstream gene enhancer

BACKGROUND. Our objective was to identify factors other than androgen receptor that bind to and regulate the prostate-specific antigen (PSA) upstream gene enhancer (PSE). METHODS. DNAse I footprinting and electromobility shift assays (EMSA) were performed over the PSE using lysates from PSA-producing cell lines, LNCaP and LAPC4, and nonproducing PSA cell lines, PC-3 cells, U937 monocytes, and Namalwa B cells. Mutational analysis and transient transfection assays were used to determine the contributions made by different elements towards the regulation of the enhancer. RESULTS. Three distinct regions surrounding androgen response elements of the PSE were found to bind unknown ubiquitous and cell type-specific proteins. These regions, when mutated in a PSE reporter construct, were shown to be required for maximal activation in LNCaP cells. CONCLUSIONS. These results correlate unknown sequence-specific DNA binding proteins with androgen-mediated regulation of a prostate-specific gene, thus providing further insight into the mechanism of PSA gene expression.