Characterization of a mutant type-1 angiotensin II receptor

We have used PCR to amplify the rat AT1 receptor from liver mRNA. The receptor DNA was subcloned into pcDNAI and a number of individual clones were transiently expressed in COS-7 cells. These individual receptors were characterized by binding of [125I] Sar1, Ile8-angiotensin II. It was found that one of the AT1 receptor clones did not bind the radiolabeled angiotensin II ligand. The mutant clone was analyzed by nucleotide sequencing. This analysis revealed that the clone has a single amino acid substitution in the third transmembrane domain of the receptor; a leucine at position 112 was changed to a proline. At this stage it is not known whether the mutant receptor is the result of a PCR artifact or an allelic difference.