Molecular cloning and functional characterization of a mouse bradykinin B1 receptor gene

The gene encoding a putative mouse bradykinin B1 receptor was cloned from a genomic library by low stringency screening. Analysis of two isolated clones revealed a region which contains an open reading frame uninterrupted by introns and encodes a 334 amino acid protein, which exhibits seven potential transmembrane domains and is 68% identical to the human and rabbit bradykinin B1 receptors, Lipopolysaccharide-treatment induces B1 receptor transcripts in the heart, liver and lung, Stable expression of the coding region in COS-7 cells resulted in high levels of binding sites for the specific B1 ligand des-Arg(10) kallidin (K-d = 1.3 nM; B-max = 51 fmol/mg protein). The rank order of affinity of the receptor for the agonists and antagonists was: des Arg(9)BKdes-Arg(9)Leu(8)BKdrs-Arg(10)kallidin much greater than Hoe-140 = bradykinin. Functional coupling of the cloned receptor was demonstrated by the dose-dependent effect of des-Arg(9)BK on the extracellular acidification rate in stably transfected COS-7 cells. This effect was not produced by bradykinin and could be blocked by the B1 antagonist des-Arg(9)Leu(8)BK. (C) 1996 Academic Press, Inc.