Yamamoto T, McIntyre J, Sell S M, Georgopoulos C, Skowyra D, Zylicz M
J Biol Chem. 1987 Jun 15;262(17):7996-9.
We have examined some of the early pre-priming steps of bacteriophage lambda dv DNA replication in vitro. Previous experiments have shown that bacteriophage lambda replication requires host RNA polymerase-dependent RNA synthesis near or at the origin of replication (ori lambda) to initiate DNA synthesis. Using a crude Fraction II enzymatic system we have shown that during RNA polymerase action, at least the bacteriophage lambda O and lambda P replication proteins as well as the host dnaB protein must be present to initiate ori lambda-specific DNA replication. The presence of three other host initiation proteins, dnaG primase, dnaJ, and dnaK, is not required during RNA polymerase action. Because of the apparent absence of a requirement for the dnaJ and dnaK pre-priming proteins during the transcriptional activation step, we propose that the early events of lambda dv DNA replication, prior to action by the dnaG primase, can be divided into two recognizable steps: an early step which requires at least RNA polymerase, lambda O, lambda P, and dnaB, and a subsequent step which requires the action of at least the dnaJ and dnaK proteins.
我们已经研究了噬菌体λ dv DNA体外复制的一些早期预引发步骤。先前的实验表明，噬菌体λ复制需要在复制起点（ori λ）附近或起点处进行宿主RNA聚合酶依赖性的RNA合成，以启动DNA合成。使用粗制的II组分酶系统，我们已经表明，在RNA聚合酶作用期间，至少必须存在噬菌体λ O和λ P复制蛋白以及宿主dnaB蛋白，才能启动ori λ特异性DNA复制。在RNA聚合酶作用期间，不需要另外三种宿主起始蛋白dnaG引发酶、dnaJ和dnaK。由于在转录激活步骤中显然不需要dnaJ和dnaK预引发蛋白，我们提出，在dnaG引发酶作用之前，λ dv DNA复制的早期事件可以分为两个可识别的步骤：一个早期步骤，至少需要RNA聚合酶、λ O、λ P和dnaB；以及随后的一个步骤，至少需要dnaJ和dnaK蛋白的作用。
