Branch migration through DNA sequence heterology
Branch migration through DNA sequence heterology
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DOI：
10.1006/jmbi.1998.1769
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发表时间：
1998-06-19
影响因子：
5.6
通讯作者：
Hsieh, P
中科院分区：
文献类型：
--
作者：
Biswas, I;Yamamoto, A;Hsieh, P
DNA霍利迪连接的分支迁移是基因重组的关键步骤。以前，它表明，一个单一的碱基对之间的异质性，否则相同的DNA序列是一个实质性的障碍，通过霍利迪交界处在自发的分支迁移。在这里，我们利用这种抑制效应的序列异质性估计的步长的分支迁移。我们还设计了一个模拟的分支迁移通过错配的碱基对，以达到在潜在的分子基础上的块分支迁移所施加的序列异质性。基于两个相邻的序列异质性或多或少独立地对分支迁移产生影响的观察，我们得出结论，分支迁移的步长是相当小的，每个迁移步骤的数量级为一个或两个碱基对。比较分支迁移实验，通过一个单一的碱基对异源性与模拟的随机步行通过序列异源性表明，抑制分支迁移主要是由于在异源双链DNA中的未配对或错配碱基的形成所产生的热力学障碍。(C)出版社：Academic Press Limited。
Branch migration of a DNA Holliday junction is a key step in genetic recombination. Previously, it was shown that a single base-pair heterology between two otherwise identical DNA sequences is a substantial barrier to passage of a Holliday junction during spontaneous branch migration. Here, we exploit this inhibitory effect of sequence heterology to estimate the step size of branch migration. We also devise a simulation of branch migration through mismatched base-pairs to arrive at the underlying molecular basis for the block to branch migration imposed by sequence heterology. Based on the observation that two adjacent sequence heterologies exert their effects on branch migration more or less independently, we conclude that the step size of branch migration is quite small, of the order of one or two base-pairs per migratory step. Comparison of branch migration experiments through a single base-pair heterology with simulations of a random walk through sequence heterology suggests that the inhibition of branch migration is largely attributable to a thermodynamic barrier arising from the formation of unpaired or mispaired bases in heteroduplex DNAs. (C) 1998 Academic Press Limited.