Isolation of cDNAs encoding a novel member of the neurotransmitter transporter gene family

Degenerate oligonucleotides deduced from two regions of the rat gamma-aminobutyric acid (GABA) transporter were used to amplify related sequences from rat spinal cord by polymerase chain reaction (PCR). The resulting product then allowed isolation of two overlapping cDNA clones with an open reading frame encoding a hydrophobic polypeptide of 630 amino acids. This protein, termed NTT, exhibits 38% sequence homology to the GABA and 48% to the noradrenaline transporters and contains 12 putative transmembrane regions. PCR amplification revealed low-level expression of NTT transcripts in spinal cord, but not in brain and cerebellum.