Cloning and expression of a human kidney cDNA for an α₂-adrenergic receptor subtype

An α₂-adrenergic receptor subtype has been cloned from a human kidney cDNA library using the gene for the human platelet α₂-adrenergic receptor as a probe. The deduced amino acid sequence resembles the human platelet α₂-adrenergic receptor and is consistent with the structure of other members of the family of guanine nucleotide-binding protein-coupled receptors. The cDNA was expressed in a mammalian cell line (COS-7), and the α₂-adrenergic ligand [³H]rauwolscine was bound. Competition curve analysis with a variety of adrenergic ligands suggests that this cDNA clone represents the α₂B-adrenergic receptor. The gene for this receptor is on human chromosome 4, whereas the gene for the human platelet α₂-adrenergic receptor (α₂A) lies on chromosome 10. This ability to express the receptor in mammalian cells, free of other adrenergic receptor subtypes, should help in developing more selective α-adrenergic ligands.