Further characterization of the 5′‐flanking promoter region of the human β1‐adrenergic receptor gene

Further characterization of the 5′‐flanking promoter region of the human β1‐adrenergic receptor (AR) gene was attempted. The transcription initiation sites, determined by the primer extension and the rapid amplification of the 5′‐cDNA end, are multiple in a spanning about 30 nucleotides (−289 to −261 relative to the translation start site). There exist inverted CCAAT boxes, multiple binding sites for transcription factor Sp1 and AP‐2 nearby transcription initiation sites, however, this region lacks a typical TATA box. In order to localize the regulatory region for the basal transcription of the human β1‐AR gene, a variety of 5′‐flanking sequence/chloramphenicol acetyltransferase reporter gene fusion constructs was prepared and transiently expressed in HeLa cells. Functional analyses reveal negatively (−3813 to −2925 and −1772 to −796) as well as positively (−2925 to −1772) regulatory regions, in addition to the region (−796 to −87) being necessary for the basic expression of the human β1‐AR gene.