Isolation and characterization of the gene encoding the rat α 1B adrenergic receptor

Abstract

Using a rat α 1B adrenergic receptor(AR)-encoding cDNA probe, we isolated two genomic clones from a rat liver genomic DNA library. Southern blot analysis and nucleotide sequencing indicate that the rat α 1B AR gene has two exons and a single large intron of at least 16 kb. Analysis of the sequence of the 5'-flanking region suggests that this gene has the features of a housekeeping gene: it has neither a TATA box nor a CAAT box, but has multiple transcription start points ( tsp), multiple Sp1-binding sites, and a high G + C content. The 5'-flanking region also contains consensus sequences for AP1-and AP2-binding sites, and putative sites for cyclic AMP ( CRE), glucocorticoid (GRE), and thyroid responses ( TRE). The 3'-flanking region contains a putative polyadenylation signal (ATTAAA) 492 bp downstream from the stop codon. A comparison of the rat α 1B AR sequence with that of the recently cloned human α 1B AR gene showed that the overall structure of this gene is highly conserved, with some notable differences in the 5'-flanking region.