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Isolation and characterization of human Nramp cDNA
1Department of Pediatrics, Yamaguchi University School of Medicine, Japan.
Abstract:
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.
Insights
Researchers identified the human natural resistance-associated macrophage protein gene (Nramp). This gene is crucial for macrophage function and shows high homology to its mouse counterpart, aiding in understanding immune responses.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- The Lsh/Ity/Bcg gene locus in mice regulates macrophage activation against intracellular pathogens.
- A mouse gene, Nramp, encodes a membrane protein homologous to transport systems, implicated in this regulation.
Purpose of the Study:
- To isolate and characterize the human Nramp gene and its encoded protein.
- To investigate the structural and genomic properties of human Nramp.
Main Methods:
- Screening of a human monocyte cDNA library to isolate human Nramp cDNA.
- Sequence analysis to determine protein characteristics and homology.
- Southern and Northern blot analyses to assess gene copy number and mRNA expression.
Main Results:
- Isolation of a 2245 bp human Nramp cDNA encoding a 483 amino acid protein (52.8 kDa).
- The deduced human Nramp amino acid sequence exhibits 89% homology to mouse Nramp.
- Genomic analysis revealed a single human Nramp gene and a single mRNA transcript of approximately 2.5 kb.
Conclusions:
- The human Nramp gene has been successfully isolated and characterized.
- Human Nramp shares significant structural and genomic similarities with its mouse ortholog.
- These findings provide a basis for further research into Nramp's role in human immunity and disease.