Isolation and characterization of human Nramp cDNA.

The mouse gene locus Lsh/Ity/Bcg regulates macrophage activation for antimicrobial activity against intracellular pathogens. A candidate gene, designated natural resistance-associated macrophage protein gene (Nramp), recently isolated from a mouse pre-B cell cDNA library, encodes an integral membrane protein that has structural homology with known prokaryotic and eukaryotic transport systems. In the present study, the cDNA for human Nramp was isolated by screening a human monocyte cDNA library. The cDNA was 2245 bp in length and coded for a protein of 483 amino acid residues with a molecular weight mass of 52.8 kDa. The deduced amino acid sequence was 89% homologous with that of mouse. Southern blot analysis indicated a single gene for Nramp counterpart in the human genome. Northern blot analysis revealed a single species of mRNA of approximately 2.5 kb.