Premium
Induction of A:T mutations is dependent on cellular environment but independent of target gene location
Author(s) -
Wang JiYang,
Kano Chie
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb36
Subject(s) - somatic hypermutation , microbiology and biotechnology , activation induced (cytidine) deaminase , gene , cytidine deaminase , biology , mutation , germinal center , reporter gene , transgene , germline mutation , genetics , b cell , gene expression , antibody
The somatic hypermutation of the immunoglobulin (Ig) genes is initiated by the activation‐induced cytidine deaminase (AID), which catalyzes the deamination of cytosine to uracil and generates a U:G DNA lesion. Consistent with its substrate specificity, ectopic expression of AID in fibroblasts induces predominantly C:G mutations in a GFP reporter gene. In contrast to fibroblasts, AID induces a high proportion of A:T mutations in Ig genes in the germinal center (GC) B cells. To investigate whether the ability to generate A:T mutations is dependent on cellular environment or target gene, we introduced a GFP gene into a GC B‐like cell line Ramos and compared the AID‐induced mutations in the endogenous Ig V H and the transgenic GFP genes. Remarkably, a high proportion of A:T mutations was induced in both genes. Moreover, using a lacZ ‐transgenic system to detect endogenous genome mutations, we found that GC B cells exhibited a much higher proportion of A:T mutations as compared with naïve B, non‐GC B and cells of other tissues. These results demonstrate that the ability to generate A:T mutations is dependent on the GC B cell environment but independent of the target gene location.