Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2006-10-3
pubmed:abstractText
Somatic hypermutation (SHM) and class switch recombination (CSR) are initiated by activation-induced cytosine deaminase (AID). The uracil, and potentially neighboring bases, are processed by error-prone base excision repair and mismatch repair. Deficiencies in Ung, Msh2, or Msh6 affect SHM and CSR. To determine whether Msh2/Msh6 complexes which recognize single-base mismatches and loops were the only mismatch-recognition complexes required for SHM and CSR, we analyzed these processes in Msh6(-/-)Ung(-/-) mice. SHM and CSR were affected in the same degree and fashion as in Msh2(-/-)Ung(-/-) mice; mutations were mostly C,G transitions and CSR was greatly reduced, making Msh2/Msh3 contributions unlikely. Inactivating Ung alone reduced mutations from A and T, suggesting that, depending on the DNA sequence, varying proportions of A,T mutations arise by error-prone long-patch base excision repair. Further, in Msh6(-/-)Ung(-/-) mice the 5' end and the 3' region of Ig genes was spared from mutations as in wild-type mice, confirming that AID does not act in these regions. Finally, because in the absence of both Ung and Msh6, transition mutations from C and G likely are "footprints" of AID, the data show that the activity of AID is restricted drastically in vivo compared with AID in cell-free assays.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
177
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5386-92
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Somatic hypermutation and class switch recombination in Msh6(-/-)Ung(-/-) double-knockout mice.
pubmed:affiliation
Department of Molecular Genetic and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural