title: Uracil residues dependent on the deaminase AID in immunoglobulin gene variable and switch regions.
abstract: Activation-induced deaminase (AID) initiates diversity of immunoglobulin genes through deamination of cytosine to uracil. Two opposing models have been proposed for the deamination of DNA or RNA by AID. Although most data support DNA deamination, there is no physical evidence of uracil residues in immunoglobulin genes. Here we demonstrate their presence by determining the sensitivity of DNA to digestion with uracil DNA glycosylase (UNG) and abasic endonuclease. Using several methods of detection, we identified uracil residues in the variable and switch regions. Uracil residues were generated within 24 h of B cell stimulation, were present on both DNA strands and were found to replace mainly cytosine bases. Our data provide direct evidence for the model that AID functions by deaminating cytosine residues in DNA.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Maul
authors.forename: Huseyin
authors.initials: H
authors.lastname: Saribasak
authors.forename: Stella A
authors.initials: SA
authors.lastname: Martomo
authors.forename: Rhonda L
authors.initials: RL
authors.lastname: McClure
authors.forename: William
authors.initials: W
authors.lastname: Yang
authors.forename: Alexandra
authors.initials: A
authors.lastname: Vaisman
authors.forename: Hillary S
authors.initials: HS
authors.lastname: Gramlich
authors.forename: David G
authors.initials: DG
authors.lastname: Schatz
authors.forename: Roger
authors.initials: R
authors.lastname: Woodgate
authors.forename: David M
authors.initials: DM
authors.lastname: Wilson
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Gearhart
mesh_terms: D000818:Animals; D000940:Antigenic Variation / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D003564:Cytidine Deaminase / Q000235:genetics / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics / Q000378:metabolism*; D017578:Immunoglobulin Class Switching; D007135:Immunoglobulin Variable Region; D015847:Interleukin-4 / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008956:Models, Chemical; D013154:Spleen / Q000473:pathology; D014498:Uracil / Q000032:analysis; D051981:Uracil-DNA Glycosidase / Q000235:genetics / Q000378:metabolism*; D000098830:AICDA (Activation-Induced Cytidine Deaminase)
chemical_list: D007135:Immunoglobulin Variable Region; D008070:Lipopolysaccharides; D015847:Interleukin-4; D014498:Uracil; D051981:Uracil-DNA Glycosidase; D000098830:AICDA (Activation-Induced Cytidine Deaminase); D003564:Cytidine Deaminase; C486216:Apex1 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase