ESCHERICHIA-COLI TUS PROTEIN ACTS TO ARREST THE PROGRESSION OF DNA-REPLICATION FORKS INVITRO
ESCHERICHIA-COLI TUS PROTEIN ACTS TO ARREST THE PROGRESSION OF DNA-REPLICATION FORKS INVITRO
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DOI：
10.1073/pnas.87.7.2481
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发表时间：
1990-04-01
影响因子：
11.1
通讯作者：
MARIANS, KJ
中科院分区：
文献类型：
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作者：
HILL, TM;MARIANS, KJ
当DNA结合蛋白Tus与大肠杆菌染色体末端区发现的4个23碱基对终止位点（ter）中的任何一个形成复合体时，极性DNA复制屏障就形成了。我们在体外用纯化蛋白重组的质粒DNA复制系统来研究Tus蛋白与复制叉的相互作用。仅纯化的Tus蛋白就足以阻止含有ter位点的cole1型质粒模板上的DNA复制。蛋白质催化的终止取决于质粒DNA中ter位点的方向。终止的新生DNA的核苷酸分辨率图谱显示，前导链DNA合成在与Tus蛋白接触的点停止，而最后的滞后链引物位点在上游50-70个核苷酸处。此外，当复制叉的滞后链一侧的蛋白质组成发生改变时，前导链阻滞位点的分布也会发生变化。
A polar DNA replication barrier is formed when the DNA-binding protein Tus forms a complex with any of the four 23-base-pair terminator (ter) sites found in the terminus region of the Escherichia coli chromosome. We have used a plasmid DNA replication system reconstituted with purified proteins in vitro to investigate the interaction of the Tus protein with the replication fork. Purified Tus protein alone is necessary and sufficient to arrest DNA replication on ColE1-type plasmid templates containing ter sites. Tus protein-catalyzed termination depends upon the orientation of the ter site in the plasmid DNA. Nucleotide resolution mapping of the terminated nascent DNA shows that leading-strand DNA synthesis arrests at the point of contact with the Tus protein, while the final lagging-strand primer sites are 50-70 nucleotides upstream. In addition, the distribution of leading-strand arrest sites changes when the composition of the proteins on the lagging-strand side of the replication fork is altered.