Abstract
Antibody class switching in activated B cells uses class switch recombination (CSR), which joins activation-induced cytidine deaminase (AID)-dependent double-strand breaks (DSBs) within two large immunoglobulin heavy chain (IgH) locus switch (S) regions that lie up to 200 kilobases apart. To test postulated roles of S regions and AID in CSR, we generated mutant B cells in which donor Smu and accepter Sgamma1 regions were replaced with yeast I-SceI endonuclease sites. We found that site-specific I-SceI DSBs mediate recombinational IgH locus class switching from IgM to IgG1 without S regions or AID. We propose that CSR evolved to exploit a general DNA repair process that promotes joining of widely separated DSBs within a chromosome.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
B-Lymphocytes / immunology*
-
Base Sequence
-
Cell Line
-
Cytidine Deaminase / metabolism*
-
DNA Breaks, Double-Stranded*
-
DNA Repair
-
Deoxyribonucleases, Type II Site-Specific / genetics
-
Deoxyribonucleases, Type II Site-Specific / metabolism*
-
Embryonic Stem Cells
-
Gene Targeting
-
Genes, Immunoglobulin Heavy Chain
-
Hybridomas
-
Immunoglobulin Class Switching*
-
Immunoglobulin G / biosynthesis
-
Immunoglobulin G / genetics
-
Immunoglobulin M / biosynthesis
-
Immunoglobulin M / genetics
-
Immunoglobulin Switch Region*
-
Lymphocyte Activation
-
Mice
-
Mice, Inbred C57BL
-
Molecular Sequence Data
-
Mutation
-
Recombination, Genetic
-
Saccharomyces cerevisiae / enzymology
-
Saccharomyces cerevisiae Proteins
Substances
-
Immunoglobulin G
-
Immunoglobulin M
-
Saccharomyces cerevisiae Proteins
-
SCEI protein, S cerevisiae
-
Deoxyribonucleases, Type II Site-Specific
-
AICDA (activation-induced cytidine deaminase)
-
Cytidine Deaminase