Multiple Protein Factors Interact with the cis-Regulatory Elements of the Proximal Promoter in a Cell-Specific Manner and Reg\ ulate Transcription of the Dopamine b-Hydroxylase Gene

摘要: The dopamine beta-hydroxylase (DBH) gene is expressed selectively in noradrenergic and adrenergic neurons neuroendocrine cells the nervous system. A cAMP response element (CRE) residing at -181 to -174 bp from transcription start site of human DBH seems be essential for transcription. Potential cis-regulatory motifs such as AP1 YY1 occur proximal overlap this CRE, endowing area with a composite promoter structure. Using DBH-expressing neuroblastoma SK-N-BE(2)C DBH-negative HeLa cell lines model systems, we report here that CRE/YY1/AP1 interacts multiple nuclear proteins, including CRE-binding protein (CREB) factor cell-specific manner. In support notion proteins bind area, DNase I foot-printing analysis has demonstrated extracts protect an extended region (from -186 -150 bp) relative protected by purified CREB -171 bp). Site-directed mutational revealed differential roles potential regulation Strikingly, positively regulated basal while simultaneously regulating cAMP-mediated induction negatively, which novel mechanism function. Furthermore, three additional DNA-binding sites have been identified footprint upstream 260 promotor gene, two are cell-specific. These results whereby 5'-proximal manner coordinately regulate type-specific transcriptional activation gene.