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- Title
Mutations in AID and UNG extend the function of AID.
- Authors
Ziqiang Li; Woo, Caroline J.; Scharff, Matthew D.
- Abstract
Immunoglobulin genes produce protective antibodies by undergoing two dramatic changes. Somatic hypermutation (SHM) and/or gene conversion increases antibody affinity. Class-switch recombination (CSR) ensures that those high-affinity antibodies can acquire different effector functions and be distributed throughout the body. The enzyme activation-induced cytosine deaminase (AID) is the 'master molecule' required for all these processes. It has been very unclear how AID is targeted to the variable region for SHM and gene conversion and to the switch regions to mediate CSR. AID is a B cell-specific enzyme that converts dC to dU on single-stranded DNA. In SHM, AID produces contemplated point mutations in WRCY hot spots in antibody-variable regions. In gene conversion, AID mediates templated point mutations from immunoglobulin-like pseudogenes on the same chromosome. CSR is also associated with AID-induced point mutations in switch regions that contain reiterated sequences. Although there is still some debate about whether AID is an RNA-editing enzyme, the finding that AID causes mutations in Escherichia coli, UNG modifies the spectrum of SHM and the frequency of CSR, and the substrate of AID is single-stranded DNA leave little doubt that AID deaminates dC on single-stranded DNA.
- Subjects
IMMUNOGLOBULIN genes; RNA; ESCHERICHIA coli; GENETIC mutation; IMMUNOGLOBULINS
- Publication
Nature Immunology, 2003, Vol 4, Issue 10, p945
- ISSN
1529-2908
- Publication type
Article
- DOI
10.1038/ni1003-945