In order to promote an efficient humoral immune response, germinal center B cells modify
both the antigen recognition and effector domains by programmed genetic alterations of
their antibody genes. To do so, B cells use the enzyme activation-induced deaminase (AID),
which transforms deoxycytidine into deoxyuridine at the immunoglobulin genes, triggering
mutagenic DNA repair. Data accumulated during the past decade have significantly
advanced our understanding of how AID activity is regulated and preferentially targeted to …