ISOLATION AND CHARACTERIZATION OF THE GENE ENCODING THE RAT ALPHA(1B)ADRENERGIC-RECEPTOR

Using a rat alpha1B adrenergic receptor(AR)-encoding cDNA probe, we is olated two genomic clones from a rat liver genomic DNA library. Southe rn blot analysis and nucleotide sequencing indicate that the rat alpha 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 bo x nor a CAAT box, but has multiple transcription start points (tsp), m ultiple Sp1-binding sites, and a high G + C content. The 5'-flanking r egion also contains consensus sequences for AP1-and AP2-binding sites, and putative sites for cyclic AMP (CRE), glucocorticoid (GRE), and th yroid responses (TRE). The 3'-flanking region contains a putative poly adenylation signal (ATTAAA) 492 bp downstream from the stop codon. A c omparison of the rat alpha1B AR sequence with that of the recently clo ned human alpha1B AR gene showed that the overall structure of this ge ne is highly conserved, with some notable differences in the 5'-flanki ng region.