Multiple protein factors interact with the cis-regulatory elements of the proximal promoter in a cell-specific manner and regulate transcription of the dopamine beta-hydroxylase gene.
The dopamine beta-hydroxylase (DBH) gene is expressed selectively in noradrenergic and adrenergic neurons and neuroendocrine cells in the nervous system. A cAMP response element (CRE) residing at -181 to -174 bp from the transcription start site of the human DBH gene seems to be essential for DBH transcription. Potential cis-regulatory motifs such as AP1 and YY1 occur proximal to and overlap this CRE, endowing the area with a composite promoter structure. Using the DBH-expressing human neuroblastoma SK-N-BE(2)C and DBH-negative HeLa cell lines as model systems, we report here that this CRE/YY1/AP1 area interacts with multiple nuclear proteins, including CRE-binding protein (CREB) and transcription factor YY1 in a cell-specific manner. In support of the notion that multiple proteins bind to the CRE/YY1/AP1 area, DNase I foot-printing analysis has demonstrated that nuclear extracts protect an extended region (from -186 to -150 bp) relative to that protected by the purified CREB (from -186 to -171 bp). Site-directed mutational analysis has revealed differential roles of potential cis-regulatory motifs in regulation of DBH transcription. Strikingly, the YY1 element positively regulated basal DBH transcription while simultaneously regulating cAMP-mediated induction negatively, which is a novel mechanism of promoter function. Furthermore, three additional DNA-binding sites have been identified by DNase I footprint analysis in the upstream 260 bp promotor region of the human DBH gene, of which two sites are cell-specific. These results support a model whereby multiple proteins bind to the 5'-proximal area in a cell-specific manner and coordinately regulate the cell type-specific transcriptional activation of the DBH gene.
Seo
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H
Department of Neurology, University of Tennessee, College of Medicine, Memphis, 38163, USA.
Yang
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C
Kim
H S
HS
Kim
K S
KS
D001483:Base Sequence; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004299:Dopamine beta-Hydroxylase / Q000235:genetics* / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D005796:Genes; D005809:Genes, Regulator; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000502:physiology*; D015345:Oligonucleotide Probes / Q000235:genetics; D011401:Promoter Regions, Genetic; D013237:Stereoisomerism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured / Q000378:metabolism; D050986:YY1 Transcription Factor
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; D004299:Dopamine beta-Hydroxylase