Molecular mechanisms of recovery of stalled DNA replication fork

通过ORIC质粒DNA的体外复制，我们分析了恢复停滞的复制叉的分子机制。我们发现，跨病变DNA聚合酶POL IV很容易催化位于领先或滞后链DNA上的DNA损伤处的旁路DNA合成，并且通过这种旁路DNA合成恢复复制分叉进程。我们证明了Pol IV迅速(&lt；15秒)阻止Pol III^*与β钳之间的稳定相互作用(复合体&gt；5分钟的寿命)，导致Pol III^*从模板DNA中移除。我们的研究建议了一个模型，在该模型中，Pol III^*和Beta钳之间的相互作用是由Pol IV介导的，以确保DNA复制以最小的中断进行。

Using oriC plasmid DNA replication in vitro, we analyzed molecular mechanisms recovering the stalled replication fork. We found that a translesion DNA polymerase, Pol IV, readily catalyzed a bypass DNA synthesis at a DNA lesion placed on leading or lagging strand DNA and that the replication fork progression was resumed by this bypass DNA synthesis. We demonstrated that Pol IV rapidly (<15 sec) obstructs the stable interaction between Pol III^* and the beta clamp (the lifetime of the complex >5min), causing the removal of Pol III^* from template DNA. Our study suggests a model in which the interaction between Pol III^* and the beta clamp is mediated by Pol IV to ensure that DNA replication proceeds with minimal interruption.