rdf:type |
|
lifeskim:mentions |
|
pubmed:issue |
2
|
pubmed:dateCreated |
2004-10-20
|
pubmed:abstractText |
AID-mediated deamination of dC residues within the immunoglobulin locus generates dU:dG lesions whose resolution leads to class-switch recombination and somatic hypermutation. The dU:dG pair is a mismatch and comprises a base foreign to DNA and is, thus, recognized by proteins from both base excision (uracil-DNA glycosylase, UNG) and mismatch recognition (MSH2/MSH6) pathways. Strikingly, while antibody diversification is perturbed by single deficiency in either UNG or MSH2, combined UNG/MSH2 deficiency leads to a total ablation both of switch recombination and of IgV hypermutation at dA:dT pairs. The initiating dU:dG lesions appear not to be recognized and are simply replicated over. The results indicate that the major pathway for switch recombination occurs through uracil excision with mismatch recognition of dU:dG providing a backup; the second phase of hypermutation (essentially introducing mutations solely at dA:dT pairs) is triggered by mismatch recognition of the dU:dG lesion with uracil excision providing a backup.
|
pubmed:language |
eng
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pubmed:journal |
|
pubmed:citationSubset |
IM
|
pubmed:chemical |
|
pubmed:status |
MEDLINE
|
pubmed:month |
Oct
|
pubmed:issn |
1097-2765
|
pubmed:author |
|
pubmed:issnType |
Print
|
pubmed:day |
22
|
pubmed:volume |
16
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
163-71
|
pubmed:dateRevised |
2006-11-15
|
pubmed:meshHeading |
pubmed-meshheading:15494304-Animals,
pubmed-meshheading:15494304-B-Lymphocytes,
pubmed-meshheading:15494304-DNA Glycosylases,
pubmed-meshheading:15494304-DNA Repair,
pubmed-meshheading:15494304-DNA-Binding Proteins,
pubmed-meshheading:15494304-Immunoglobulin Class Switching,
pubmed-meshheading:15494304-Immunoglobulin Variable Region,
pubmed-meshheading:15494304-Immunoglobulins,
pubmed-meshheading:15494304-Mice,
pubmed-meshheading:15494304-MutS Homolog 2 Protein,
pubmed-meshheading:15494304-Mutation,
pubmed-meshheading:15494304-Proto-Oncogene Proteins,
pubmed-meshheading:15494304-Uracil,
pubmed-meshheading:15494304-Uracil-DNA Glycosidase
|
pubmed:year |
2004
|
pubmed:articleTitle |
Mismatch recognition and uracil excision provide complementary paths to both Ig switching and the A/T-focused phase of somatic mutation.
|
pubmed:affiliation |
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom. car@mrc-lmb.cam.ac.uk
|
pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|