Human dopamine D1 receptor encoded by an intronless gene on chromosome 5

RECEPTORS for dopamine have been classified into two functional types, D 1 and D 2 (refs 1,2). They belong to the family of receptors acting through G (or guanine nucleotide-binding) proteins 3 . D 2 receptors inhibit adenylyl cyclase, but D 1 receptors stimulate adenylyl cyclase and activate cyclic AMP-dependent protein kinases 4,5 . Dopamine D 1 and D 2 receptors are targets of drug therapy in many psychomotor disorders, including Parkinson's disease and schizophrenia 6,7 , and may also have a role in drug addiction and alchoholism 8 . D 1 receptors regulate neuron growth and differentiation 9 , influence behaviour and modify dopamine D 2 receptor-mediated events 10,11 . We report here the cloning of the D 1 receptor gene, which resides on an intronless region on the long arm of chromosome 5, near two other members of the G-linked receptor family. The expressed protein, encoded by 446 amino acids, binds drugs with affinities identical to the native human D 1 receptor. The presence of a D 1 receptor gene restriction fragment length polymorphism will be helpful for future disease linkage studies.