Ramsden D A, van Gent D C, Gellert M
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Building 5, National Institutes of Health, Bethesda, MD 20892-0540, USA.
Curr Opin Immunol. 1997 Feb;9(1):114-20. doi: 10.1016/s0952-7915(97)80167-7.
Recent in vitro work on V(D)J recombination has helped to clarify its mechanism. The first stage of the reaction, which can be reproduced with the purified RAG1 and RAG2 proteins, is a site-specific cleavage that generates the same broken DNA species found in vivo. The cleavage reaction is closely related to known types of transpositional recombination, such as that of HIV integrase. All the site specificity of V(D)J recombination, including the 12/23 rule, is determined by the RAG proteins. The later steps largely overlap with the repair of radiation-induced DNA double-strand breaks, as indicated by the identity of several newly characterized factors involved in repair. These developments open the way for a thorough biochemical study of V(D)J recombination.
最近关于V(D)J重组的体外研究有助于阐明其机制。反应的第一阶段，可通过纯化的RAG1和RAG2蛋白重现，是一种位点特异性切割，产生与体内发现的相同的断裂DNA片段。切割反应与已知类型的转座重组密切相关，如HIV整合酶的重组。V(D)J重组的所有位点特异性，包括12/23规则，都由RAG蛋白决定。如参与修复的几个新鉴定因子的一致性所示，后续步骤在很大程度上与辐射诱导的DNA双链断裂的修复重叠。这些进展为对V(D)J重组进行全面的生化研究开辟了道路。
