title: Antibody class switching mediated by yeast endonuclease-generated DNA breaks.
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.
authors.affiliation: Howard Hughes Medical Institute, Children's Hospital, CBR Institute for Biomedical Research, and Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Zarrin
authors.forename: Catherine
authors.initials: C
authors.lastname: Del Vecchio
authors.forename: Eva
authors.initials: E
authors.lastname: Tseng
authors.forename: Megan
authors.initials: M
authors.lastname: Gleason
authors.forename: Payam
authors.initials: P
authors.lastname: Zarin
authors.forename: Ming
authors.initials: M
authors.lastname: Tian
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Alt
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002460:Cell Line; D003564:Cytidine Deaminase / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics / Q000378:metabolism*; D053595:Embryonic Stem Cells; D018390:Gene Targeting; D050438:Genes, Immunoglobulin Heavy Chain; D006825:Hybridomas; D017578:Immunoglobulin Class Switching; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000235:genetics; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000235:genetics; D007134:Immunoglobulin Switch Region; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009154:Mutation; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D029701:Saccharomyces cerevisiae Proteins; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase