Identity of the F52F12.1 gene product in Caenorhabditis elegans as an organic cation transporter.

We describe here the cloning and functional characterization of an organic cation transporter from Caenorhabditis elegans (CeOCT1). The CeOCT1 cDNA is 1826 bp long and codes for a protein of 568 amino acids. The oct1 gene is approximately 3.2 kb in size and consists of 12 exons. The location of this gene corresponds to the F52F12.1 gene locus on chromosome I. The predicted protein contains 12 putative transmembrane domains. It exhibits significant homology to mammalian OCTs. When expressed in mammalian cells, CeOCT1 induces the transport of the prototypical organic cation tetraethylammonium. The Michaelis-Menten constant for this substrate is 80+/-16 microM. The substrate specificity of CeOCT1 is broad. This represents the first report on the cloning and functional characteristics of an organic cation transporter from C. elegans.