Strand displacement synthesis by yeast DNA polymerase ε.
Strand displacement synthesis by yeast DNA polymerase ε.
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DOI：
10.1093/nar/gkw556
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发表时间：
2016-09-30
影响因子：
14.9
通讯作者：
Johansson E
中科院分区：
文献类型：
--
作者：
Ganai RA;Zhang XP;Heyer WD;Johansson E
DNA聚合酶ε（Pol ε）是一种具有相关3′–5′核酸外切酶活性的复制性DNA聚合酶。在此，我们探究了Pol ε进行链置换合成的能力，这是一个影响体内许多DNA代谢过程的过程。我们发现，除非其3′–5′核酸外切酶活性被去除，否则Pol ε无法进行长链的链置换合成。然而，野生型Pol ε全酶在填补缺口或切割DNA后遇到双链DNA时，能有效地置换一个核苷酸。在阻断引物的5′端的一个瓣状结构（模拟D环或发夹结构）会抑制Pol ε合成DNA直至叉状连接点。这种抑制作用在Pol ε中被观察到，但在Pol δ、RB69 gp43或Pol η中未观察到。在重组实验中，Pol ε也无法延伸D环。最后，我们表明核酸外切酶缺陷型Pol ε所观察到的链置换合成是分散性的。我们的结果表明，在同源重组过程中，Pol ε无法延伸D环中的侵入链，在长补丁碱基切除修复过程中也无法添加超过两个核苷酸。我们的结果支持Pol ε参与短补丁碱基切除修复和核糖核苷酸切除修复这一假说。
DNA polymerase ε (Pol ε) is a replicative DNA polymerase with an associated 3′–5′ exonuclease activity. Here, we explored the capacity of Pol ε to perform strand displacement synthesis, a process that influences many DNA transactions in vivo. We found that Pol ε is unable to carry out extended strand displacement synthesis unless its 3′–5′ exonuclease activity is removed. However, the wild-type Pol ε holoenzyme efficiently displaced one nucleotide when encountering double-stranded DNA after filling a gap or nicked DNA. A flap, mimicking a D-loop or a hairpin structure, on the 5′ end of the blocking primer inhibited Pol ε from synthesizing DNA up to the fork junction. This inhibition was observed for Pol ε but not with Pol δ, RB69 gp43 or Pol η. Neither was Pol ε able to extend a D-loop in reconstitution experiments. Finally, we show that the observed strand displacement synthesis by exonuclease-deficient Pol ε is distributive. Our results suggest that Pol ε is unable to extend the invading strand in D-loops during homologous recombination or to add more than two nucleotides during long-patch base excision repair. Our results support the hypothesis that Pol ε participates in short-patch base excision repair and ribonucleotide excision repair.
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影响因子：
4.8
作者：
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通讯作者：
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影响因子：
64.5
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真核铅和滞后链DNA聚合酶通过单独的机制加载到引物上，但在PCNA存在下具有可比的加工性。
影响因子：
14.9
作者：
Chilkova O;Stenlund P;Isoz I;Stith CM;Grabowski P;Lundström EB;Burgers PM;Johansson E
通讯作者：
Johansson E
影响因子：
14.9
作者：
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通讯作者：
Kunkel TA