Cloning and functional characterization of a cocaine-sensitive dopamine transporter.

We report the cloning of a rat cDNA encoding a functional dopamine transporter. This cDNA, derived from an intron-containing gene, encodes a protein of 620 amino acids. Hydropathicity analysis of the protein sequence suggests the presence of 12 putative transmembrane domains. The protein displays considerable identity with transporters for noradrenaline and GABA (64 and 30%, respectively). Transient expression of the cDNA in COS7 cells directs the expression of dopamine uptake activity with appropriate pharmacology and in a sodium-dependent fashion. In situ hybridization reveals that the mRNA for this transporter is expressed in the substantia nigra and ventral tegmental area, regions that contain dopaminergic cell bodies.