Molecular cloning, mapping, and characterization of two novel human genes,ORCTL3 and ORCTL4, bearing homology to organic-cation transporters

Through a large-scale sequencing of genomic DNA at 3p22 --> p21.3, we have isolated two human genes (ORCTL3 alias OCTL1 and ORCTL4 alias OCTL2) encodi ng novel members of the family of organic-cation transporter molecules. The predicted proteins revealed the highest similarities to recently-isolated organic-cation transporter proteins, rat OCT-lr, rat NLT and mouse NKT. The transcripts of both genes were expressed ubiquitously in various human tis sues, but some tissue-specific transcripts were also observed in kidney, te stis, or skeletal muscle. The two genes are clustered within a 52-kb region of genomic DNA and ORCTL4 lies about 27 kb telomeric to ORCTL3 in the geno mic DNA sequence in a tail-to-head orientation.