Belanger K G, Kreuzer K N
Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Mol Cell. 1998 Nov;2(5):693-701. doi: 10.1016/s1097-2765(00)80167-7.
Two-dimensional gel analysis of the bacteriophage T4 ori(uvsY) region revealed a novel "comet" on the Y arc. This comet contains simple Y molecules in which the branch points map to the ori(uvsY) transcript region. The comet depends on the the origin and DNA synthesis and is abolished by a mutation that reduces replication without affecting transcription. These results argue that the branched molecules are intermediates in replication initiation. A transcriptional terminator, cloned just downstream of the origin promoter, shortened the tail of the comet. Therefore, the location of the transcript determines the DNA branch points. We conclude that the comet DNA consists of intermediates in which unidirectional replication has been triggered by priming from the RNA of the origin R loop.
对噬菌体T4 ori(uvsY)区域进行的二维凝胶分析显示，Y弧上出现了一种新型的“彗星”。这种彗星包含简单的Y分子，其中分支点定位于ori(uvsY)转录区域。该彗星依赖于起始点和DNA合成，并且因一个在不影响转录的情况下减少复制的突变而消失。这些结果表明，分支分子是复制起始过程中的中间体。一个克隆在起始点启动子下游的转录终止子缩短了彗星的“尾巴”。因此，转录本的位置决定了DNA分支点。我们得出结论，彗星DNA由中间体组成，在这些中间体中，单向复制是由来自起始点R环RNA的引发所触发的。
