Requirement of the Activation-Induced Deaminase ( AID ) Gene for Immunoglobulin Gene Conversion

Abstract
Three phenotypically distinct processes—somatic hypermutation, gene conversion, and switch recombination—remodel the functionally rearranged immunoglobulin (Ig) loci in B cells. Somatic hypermutation and switch recombination have recently been shown to depend on the activation-induced deaminase (AID) gene product. Here, we show that the disruption of the AID gene in the chicken B cell line DT40 completely blocks Ig gene conversion and that this block can be complemented by reintroduction of theAID complementary DNA. This demonstrates that theAID master gene controls all B cell–specific modifications of vertebrate Ig genes.