Rodgers William, Byrum Jennifer N, Sapkota Hem, Rahman Negar S, Cail Robert C, Zhao Shuying, Schatz David G, Rodgers Karla K
Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Pathology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
DNA Repair (Amst). 2015 Mar;27:19-27. doi: 10.1016/j.dnarep.2014.12.008. Epub 2015 Jan 8.
V(D)J recombination of lymphocyte antigen receptor genes occurs via the formation of DNA double strand breaks (DSBs) through the activity of RAG1 and RAG2. The co-existence of RAG-independent DNA DSBs generated by genotoxic stressors potentially increases the risk of incorrect repair and chromosomal abnormalities. However, it is not known whether cellular responses to DSBs by genotoxic stressors affect the RAG complex. Using cellular imaging and subcellular fractionation approaches, we show that formation of DSBs by treating cells with DNA damaging agents causes export of nuclear RAG2. Within the cytoplasm, RAG2 exhibited substantial enrichment at the centrosome. Further, RAG2 export was sensitive to inhibition of ATM, and was reversed following DNA repair. The core region of RAG2 was sufficient for export, but not centrosome targeting, and RAG2 export was blocked by mutation of Thr(490). In summary, DNA damage triggers relocalization of RAG2 from the nucleus to centrosomes, suggesting a novel mechanism for modulating cellular responses to DSBs in developing lymphocytes.
淋巴细胞抗原受体基因的V(D)J重组是通过RAG1和RAG2的活性形成DNA双链断裂（DSB）来实现的。由遗传毒性应激源产生的不依赖RAG的DNA DSB的共存可能会增加错误修复和染色体异常的风险。然而，尚不清楚遗传毒性应激源对DSB的细胞反应是否会影响RAG复合体。通过细胞成像和亚细胞分级分离方法，我们发现用DNA损伤剂处理细胞导致DSB形成会引起核内RAG2的输出。在细胞质中，RAG2在中心体处大量富集。此外，RAG2的输出对ATM的抑制敏感，并且在DNA修复后会逆转。RAG2的核心区域足以实现输出，但不足以靶向中心体，并且Thr(490)的突变会阻止RAG2的输出。总之，DNA损伤触发RAG2从细胞核重新定位到中心体，这表明在发育中的淋巴细胞中调节细胞对DSB反应的一种新机制。
