Collateral Damage from Antigen Receptor Gene Diversification

Chromosomal translocations that juxtapose antigen receptor genes and oncogenes are frequently associated with lymphoid malignancies. In this issue, Robbiani et al. ( 2008) show that activation-induced deaminase ( AID), an enzyme involved in antigen receptor gene diversification, generates DNA double-strand breaks (DSBs) in oncogenes, and Tsai et al. ( 2008) propose that AID and the recombinase-activating gene ( RAG) endonuclease may collaborate to generate off-target DSBs.