Fig. 2
From: ATM, ATR and DNA-PKcs kinases—the lessons from the mouse models: inhibition ≠ deletion
Schematic representation of V(D)J recombination. RAG endonucleases (RAG1 and RAG2) introduce DSBs between the participating V(D)J gene segments and their flanking recombination signal sequences (RSS). RAG cleavage generates a pair of blunt signal ends (SEs) and a pair of covalently sealed hairpined coding ends (CEs). While SEs are directly and precisely ligated by the cNHEJ factors Ligase IV/XRCC4/XLF to form a signal joint (SJ), the hairpin CEs have to first be opened by DNA-PKcs/Artemis and then joined through a process that can result in gain or loss of nucleotides and leads to the formation of a coding joint (CJ)