Figure 1.

The role of Artemis in V(D)J recombination. A, using light-chain VJ recombination as an example, RAG1/RAG2 complexes (gray ovals) recognize recombination signal sequences between V and J segments and cleave the DNA to form hairpin ends. Unwanted V and J fragments are removed in this process. B, the Ku70/Ku80 complex recognizes the DNA end and recruits DNA-PKcs (pink ring) and Artemis (navy oval), which is phosphorylated by DNA-PKcs. Artemis opens the hairpin ends through its endonucleolytic activity and then processes DNA overhangs through its 5′-exonucleolytic or 5′-/3′-endonucleolytic activity. C, V and J segments are ligated together by ligase (orange oval). D, a VJ coding join is formed.