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Immunity through DNA deamination
Michael S Neuberger1, Reuben S Harris, Javier Di Noia
1Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge, UK CB2 2QH. msn@mrc-lmb.cam.ac.uk
Trends in Biochemical Sciences
|June 27, 2003
Summary
DNA deamination drives antibody gene diversification and adaptive immunity. This process, initiated by cytosine deamination, also plays roles in innate immunity, genome evolution, and cancer.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Antibody genes undergo diversification through somatic hypermutation, gene conversion, and class-switch recombination.
- These diversification processes are initiated by the deamination of cytosine to uracil within immunoglobulin loci.
Purpose of the Study:
- To elucidate the unifying mechanism of DNA deamination in antibody gene diversification.
- To explore the dual role of DNA deamination in adaptive and innate immunity.
- To investigate the potential involvement of DNA deaminases in genome evolution and cancer.
Main Methods:
- Analysis of DNA deamination pathways at immunoglobulin loci.
- Investigation of the resolution of dU-dG lesions.
- Comparative analysis of deamination targeting in endogenous versus foreign DNA.
Main Results:
- Somatic hypermutation, gene conversion, and class-switch recombination are all driven by DNA deamination.
- The specific diversification pattern depends on how the initial uracil-DNA lesion is resolved.
- Targeting deamination to endogenous immunoglobulin loci triggers adaptive immunity mechanisms.
- Deamination targeting foreign DNA may represent an ancient innate immunity mechanism.
Conclusions:
- DNA deamination is a central mechanism underlying antibody gene diversification and adaptive immunity.
- The DNA deaminase family's ability to target various genes suggests roles beyond adaptive immunity, including genome evolution and oncogenesis.