ROLES OF DNA ADENINE METHYLATION IN CONTROLLING REPLICATION OF THE REPI REPLICON OF PLASMID PCOIV-K30
ROLES OF DNA ADENINE METHYLATION IN CONTROLLING REPLICATION OF THE REPI REPLICON OF PLASMID PCOIV-K30
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DOI：
10.1111/j.1365-2958.1991.tb02133.x
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发表时间：
1991-02-01
影响因子：
3.6
通讯作者：
CROSA, JH
中科院分区：
文献类型：
--
作者：
GAMMIE, AE;CROSA, JH
DNA腺嘌呤甲基化通过影响蛋白质识别和改变起始点的螺旋稳定性来控制含有原型REPI复制子的质粒的DNA复制。变性梯度凝胶电泳显示腺嘌呤甲基化的起始DNA比未甲基化的更容易解链。然而，由于在起点处添加的DNA腺嘌呤甲基化（dam）位点，无论是与其他螺旋对齐的dam位点同相还是异相，实际上都阻止了复制，因此我们得出结论，螺旋的不稳定不是腺嘌呤甲基化在REPI复制中的唯一功能。我们发现，构象和甲基化程度的起点，功能是重要的蛋白质识别，是必不可少的复制。事实上，REPI复制子的复制起始所需的蛋白质RePI含有与特异性识别并结合5 ′-GATC-3 ′的蛋白质中的结构域同源的区域。我们认为，大坝网站的起源发挥双重作用：一个是不稳定的螺旋，另一个是蛋白质识别。
DNA adenine methylation controls DNA replication of plasmids containing the prototypic REPI replicon by affecting protein recognition and by altering the helical stability of the origin. Denaturing radient gel electrophoresis shows that adenine methylated origin DNA is more easily melted than unmethylated. However, because an added DNA adenine methylation (dam) site at the origin, whether in or out of phase with other helically aligned dam sites, actually prevents replication, we conclude that destabilization of the helix is not the exclusive function of adenine methylation in REPI replication. We find that the conformation and degree of methylation at the origin, features which are important for protein recognition, are essential for replication. In fact, Repl, a protein required for replication initiation at REPI replicons, contains a region homologous with a domain in proteins which specifically recognize and bind 5'-GATC-3'. We propose that the dam sites in the origin play a dual role: one is destabilization of the helix, and the other is protein recognition.