Single-molecule analysis reveals that the lagging strand increases replisome processivity but slows replication fork progression
Single-molecule analysis reveals that the lagging strand increases replisome processivity but slows replication fork progression
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DOI：
10.1073/pnas.0906157106
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发表时间：
2009-08-11
影响因子：
11.1
通讯作者：
O'Donnell, Michael E.
中科院分区：
文献类型：
--
作者：
Yao, Nina Y.;Georgescu, Roxana E.;O'Donnell, Michael E.
单分子技术的发展，以研究机制的特点，个别E。大肠杆菌复制体在长DNA分子的合成过程中。我们发现单个复制体表现出恒定的分叉运动速率，但不同复制体的分叉运动速率在一个令人惊讶的宽范围内变化。有趣的是，滞后链的合成降低了前导链的速率，这表明滞后链的操作对复制叉的进展产生了阻力。持续性的情况正好相反。滞后链显著增加了复制体的持续合成能力，可能反映了锚定在前导链和滞后链上的滑动夹上的2种DNA聚合酶提供的对DNA的增加的抓地力。
Single-molecule techniques are developed to examine mechanistic features of individual E. coli replisomes during synthesis of long DNA molecules. We find that single replisomes exhibit constant rates of fork movement, but the rates of different replisomes vary over a surprisingly wide range. Interestingly, lagging strand synthesis decreases the rate of the leading strand, suggesting that lagging strand operations exert a drag on replication fork progression. The opposite is true for processivity. The lagging strand significantly increases the processivity of the replisome, possibly reflecting the increased grip to DNA provided by 2 DNA polymerases anchored to sliding clamps on both the leading and lagging strands.