Nishihara Tadashi, Nagawa Fumikiyo, Nishizumi Hirofumi, Kodama Masami, Hirose Satoshi, Hayashi Reiko, Sakano Hitoshi
Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
Mol Cell Biol. 2004 May;24(9):3692-702. doi: 10.1128/MCB.24.9.3692-3702.2004.
The postcleavage complex involved in V(D)J joining is known to possess a transpositional strand transfer activity, whose physiological role is yet to be clarified. Here we report that RAG1 and RAG2 proteins in the signal end (SE) complex cleave the 3'-overhanging structure of the synthetic coding-end (CE) DNA in two successive steps in vitro. The 3'-overhanging structure is attacked by the SE complex imprecisely, near the double-stranded/single-stranded (ds/ss) junction, and transferred to the SE. The transferred overhang is then resolved and cleaved precisely at the ds/ss junction, generating either the linear or the circular cleavage products. Thus, the blunt-end structure is restored for the SE and variably processed ends are generated for the synthetic CE. This 3'-processing activity is observed not only with the core RAG2 but also with the full-length protein.
已知参与V(D)J连接的切割后复合物具有转座链转移活性,其生理作用尚待阐明。在此我们报告,信号末端(SE)复合物中的RAG1和RAG2蛋白在体外分两个连续步骤切割合成编码末端(CE)DNA的3'突出结构。SE复合物在双链/单链(ds/ss)交界处附近对3'突出结构进行不精确攻击,并将其转移至SE。然后,转移的突出端在ds/ss交界处被精确切割和分解,产生线性或环状切割产物。因此,SE恢复了平端结构,而合成CE产生了可变加工的末端。不仅核心RAG2,全长蛋白也具有这种3'加工活性。