Dao N, Gao B. The simian virus 40 core C enhancer-like element is a positive regulator in the rat alpha1B adrenergic receptor gene proximal promoter.
Biochem Biophys Res Commun 1998;
253:804-8. [PMID:
9918808 DOI:
10.1006/bbrc.1998.9860]
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Abstract
Transcription of the rat alpha1B adrenergic receptor (alpha1B AR) gene is controlled by three promoters (P1, P2, and P3), which generate 2.3-, 2.7-, and 3.3-kb transcripts, respectively. The expression of the 2.3-kb mRNA species is tissue-specific. To explore the underlying mechanism, the P1 promoter was analyzed. DNase I footprinting of the P1 promoter yielded three protected regions: Plfl(-49 to -62); P1f2 (-73 to -90), and P1f3 (-95 to -115). Sequence analysis of P1f3 revealed the presence of an SV40 core C enhancer-like element. In gel mobility shift assays, P1f3 was found to bind a sequence specific protein, which was competed away by a SV40 core C enhancer consensus oligonucleotide. Mutations of this enhancer-like core sequence within P1f3 significantly reduced specific protein binding to P1f3 and inhibited P1 promoter activity. The distribution of the protein which binds to P1f3 is restricted. These findings suggest that the P1 promoter is controlled by a cell-type-specific transcription factor, which may account for the tissue-specific expression of 2.3-kb rat alpha1B AR mRNA species.
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