We report the molecular cloning of a β3-adrenergic receptor β3-AR cDNA from human brown adipose tissue. The cDNA-encoded protein is identical to the previously cloned β3-AR but with 6 additional amino acids at the C-terminus. The C-terminus is shared by the β3 receptors expressed in human neuroblastoma cells [SK-N-MC] [Mol. Pharmacol. 42 (1992) 964-970]. Furthermore, using a polymerase chain reaction strategy we have cloned and sequenced the β3-AR introns. Sequence analysis demonstrates that the human β3-AR gene comprises at least 3 exons and 2 introns and that the most abundant β3-AR transcripts encode a protein with an exon 3-derived C-terminus. Interestingly, although a similar organization has been found in rodent genes, the rat β3-AR transcripts encode a receptor with an exon 2-derived C-terminus.
