Bainton R J, Kubo K M, Feng J N, Craig N L
Department of Biochemistry and Biophysics, George W. Hooper Foundation, University of California, San Francisco 94143.
Cell. 1993 Mar 26;72(6):931-43. doi: 10.1016/0092-8674(93)90581-a.
We have reconstituted the transposition of the bacterial transposon Tn7 into its specific insertion site attTn7 with four purified Tn7-encoded proteins, TnsA+TnsB+TnsC+TnsD, and ATP. TnsA+TnsB+TnsC form a "core" recombination machine that recognizes the transposon ends and executes DNA breakage and joining; TnsD specifically recognizes attTn7. TnsA+TnsB+TnsC are specifically targeted to attTn7 through the TnsD-dependent interaction of TnsC, a nonspecific DNA-binding protein, with attTn7. Recombination appears to be activated by the assembly of a nucleoprotein complex containing the DNA substrates and Tns proteins. We suggest that TnsC plays a central role in communication between the transposon and the target DNA, particularly in directing insertion away from DNAs already containing a copy of Tn7.
我们利用四种纯化的由Tn7编码的蛋白质TnsA + TnsB + TnsC + TnsD以及ATP，在体外重建了细菌转座子Tn7向其特异性插入位点attTn7的转座过程。TnsA + TnsB + TnsC形成一个“核心”重组机器，可识别转座子末端并执行DNA断裂和连接；TnsD特异性识别attTn7。通过非特异性DNA结合蛋白TnsC与attTn7的依赖于TnsD的相互作用，TnsA + TnsB + TnsC被特异性靶向attTn7。重组似乎是由包含DNA底物和Tns蛋白的核蛋白复合物的组装所激活。我们认为TnsC在转座子与靶DNA之间的通讯中起核心作用，特别是在引导插入远离已经含有Tn7拷贝的DNA方面。
