Isolation of a murine copper transporter gene, tissue specific expression and functional complementation of a yeast copper transport mutant.

A polymerase chain reaction (PCR)-based strategy was used to isolate a mouse cDNA (mCtr1) encoding a Cu transport protein. The deduced mCtr1 protein sequence exhibits 92% identity to human Ctr1, and has structural features in common with known high affinity Cu transporters from yeast. The expression of mouse Ctr1 functionally complements baker's yeast cells defective in high affinity Cu transport. Characterization of the mCtr1 genomic clone showed that the mCtr1 coding sequence is encompassed within four exons and that the mCtr1 locus maps to chromosome band 4C1-2. RNA blotting analysis demonstrated that mCtr1 is ubiquitously expressed, with high levels in liver and kidney, and early in embryonic development. Steady state mammalian Ctr1 mRNA levels were not changed in response to cellular Cu availability, which is distinct from the highly Cu-regulated transcription of genes encoding yeast high affinity Cu transporters. These studies provide fundamental information for further investigations on the function and regulation of Ctr1 in Cu acquisition in mammals.