The agonist selectivity of a mouse B1 bradykinin receptor differs from human and rabbit B1 receptors

A genomic clone encoding the mouse B1 receptor was isolated by homology to the human B1 receptor cDNA. The deduced amino acid sequence of the mouse B1 receptor is 72% identical to the human B1 receptor and 73% identical to the rabbit B1 receptor. Ligand binding studies of the mouse B1 receptor expressed in COS cells indicate that it has the pharmacological properties associated with the B1 receptor subtype. However the pharmacology of the mouse receptor is unique in that it possesses a 2-3-fold selectivity for the 'classical' B1 agonist des-Arg9BK over the agonist des-Arg10 kallidin. In contrast, the human and rabbit B1 receptors exhibit an approx. 2000- and 150-fold selectivity, respectively, for des-Arg10kallidin over des-Arg9BK. Thus relative to the human and rabbit B1 receptors the mouse B1 receptor has the opposite selectivity for kinin agonists. The DNA sequence of the region encoding bradykinin was determined for two different mouse kininogen cDNA clones, both encode the sequence Arg-BK. Antipeptide antibodies directed against a C-terminal peptide of the human B1 receptor were produced. Initial characterization of this antibody indicates that it detects specific bands by Western blot analyses that are present in membranes prepared from COS cells transfected with the human B1 receptor cDNA but not from mock transfected COS cells.