A human nucleobase transporter-like cDNA (SLC23A1): Member of a transporter family conserved from bacteria to mammals

A family of related polytopic membrane proteins that mediate the transport of nucleobases has been extended to Homo sapiens by the cloning of a full-l ength human cDNA that encodes a nucleobase transporter-like protein. The pr otein is predicted to contain 11-14 transmembrane-spanning regions, exhibit s 20-28% overall sequence identity to fungal and bacterial transporters, an d contains a conserved signature motif found in this family. Fluorescence i n situ hybridization localized the gene (HGMW-approved symbol SLC23A1) to h uman chromosome 20p13. Human nucleobase transporter-like mRNA was present i n all tissues examined, with lower levels found in heart, skeletal muscle, and ovary. Expression of the 60-kDa cDNA-encoded protein was demonstrated b y an in vitro transcription-translation approach. The identification of thi s nucleobase transporter-like protein will allow the further elucidation of the interaction of human cells with physiological nucleobases and pharmaco logically important drugs such as 5-F-uracil, dideoxynucleosides, and acycl ic nucleosides. (C) 1999 Academic Press.