The non-core domain of RAG2 regulates various functions of the V(D)J recombinase 3185

Abstract Description V(D)J recombination of lymphocyte antigen receptor genes occurs via formation of DNA double strand breaks (DSBs) via activity of RAG1 and RAG2, termed V(D)J recombinase. Proper regulation of the V(D)J recombinase is essential to prevent aberrant recombination events that could lead to genomic instability and lymphomagenesis. Both RAG proteins are composed of a core and non-core region, where the core regions are required for DNA cleavage. The non-core region of RAG2 regulates multiple aspects of cellular properties of the V(D)J recombinase, although the mechanistic basis for these regulatory functions is poorly understood. We hypothesize multiple regions of non-core RAG2, including the acidic hinge, plant homeodomain (PHD), and C-terminal basic region, function cooperatively to regulate V(D)J recombination activity under varying cell conditions. We show RAG2 mutations in the acidic region and residues in the basic region work collectively to regulate DNA cleavage activity. Further combination of mutations demonstrates non-core RAG2 is inclined to distribute the V(D)J recombinase to membrane-less DNA poor regions under normal conditions, and re-localize the recombinase in response to excess DNA damage. We propose that while RAG2 functions to cleave DNA during V(D)J recombination, it also performs an alternate function to reinforce the cell’s response to DNA damage, prevent off-target recombination, and inhibit further cleavage activity in the face of unrepaired DNA breaks. Topic Categories Hematopoiesis and Immune System Development (HEM)