Persistent damaged bases in DNA allow mutagenic break repair in Escherichia coli.
Persistent damaged bases in DNA allow mutagenic break repair in Escherichia coli.
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DOI：
10.1371/journal.pgen.1006733
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发表时间：
2017-07
期刊：
影响因子：
4.5
通讯作者：
Hastings PJ
中科院分区：
文献类型：
--
作者：
Moore JM;Correa R;Rosenberg SM;Hastings PJ
细菌、酵母和人类癌细胞具有通过应激反应上调的诱变机制。胁迫诱导的诱变可能加速适应，并可能提供重要的诱变模型，驱动癌症，宿主病原体相互作用，抗生素耐药性和可能的大部分进化。在大肠杆菌中，双链断裂（DSB）的修复变得致突变，使用在SOS DNA损伤反应和RpoS一般应激反应的控制下的低保真度DNA聚合酶，其上调并允许易错DNA聚合酶IV（DinB）、II和V的作用在修复期间产生突变。Pol IV被暗示在DSB修复复制体处与高保真DNA聚合酶竞争并取代高保真DNA聚合酶，从而引起诱变。我们报告说，上调的Pol IV是不够的诱变断裂修复（MBR），在DNA中受损的碱基也是必需的，在饥饿应激的细胞，这些是由活性氧（ROS）。首先，MBR被ROS清除剂或氧化损伤反应的组成性激活减少，这两者都降低细胞ROS水平。ROS促进MBR，而不是通过引起DSB，饱和错配修复，氧化蛋白质或诱导SOS反应或一般应激反应。我们发现ROS通过DNA中的氧化鸟嘌呤（8-oxo-dG）驱动MBR，因为从DNA中去除8-oxo-dG的糖基化酶的过度产生阻止了MBR。此外，其他受损的DNA碱基可以取代8-氧代-dG，因为如果DNA嘧啶二聚体或烷基化碱基被诱导，ROS清除的细胞恢复MBR。我们假设DNA中受损的碱基暂停了复制体，并允许从高保真到DSB修复复制体中的易错DNA聚合酶的关键切换，从而允许MBR。这些数据意味着，除了间接的压力响应控制开关MBR，直接顺式作用开关MBR发生独立的DNA断裂，造成的ROS氧化的DNA可能受到ROS调节。由应激反应上调的突变机制促进细菌中的从头抗生素抗性和交叉抗性、酵母中的抗真菌药物抗性以及缺氧应激下癌细胞中的基因组不稳定性。胁迫诱导的诱变被认为是驱动细菌进化的自发诱变的主要来源，并且通常可以驱动大部分进化。一个广泛使用的模型机制是大肠杆菌中的诱变DNA断裂修复，其中两种应激反应的激活允许断裂修复复制体中的易错DNA聚合酶并引入错配，随后作为突变固定。这两种压力反应上调的易错的诱变DNA聚合酶Pol IV（DinB），这表明调节诱变的时间的压力是通过间接的基因上调，然后通过DNA聚合酶的竞争。这篇论文描述了这样的发现，即应激反应不足以允许由断裂-修复复制体中的易错DNA聚合酶引起的诱变--还必须存在受损的DNA碱基--并且这些是由饥饿的E.杆菌我们推测，受损的碱基可能会抑制高度进行性和高保真复制的DNA聚合酶的进展，从而允许切换到易错的DNA聚合酶和诱变。这些发现表明，自发突变率可能是由活性氧的产生和清除调节的，活性氧是代谢的一种非常常见的副产品。
Bacteria, yeast and human cancer cells possess mechanisms of mutagenesis upregulated by stress responses. Stress-inducible mutagenesis potentially accelerates adaptation, and may provide important models for mutagenesis that drives cancers, host pathogen interactions, antibiotic resistance and possibly much of evolution generally. In Escherichia coli repair of double-strand breaks (DSBs) becomes mutagenic, using low-fidelity DNA polymerases under the control of the SOS DNA-damage response and RpoS general stress response, which upregulate and allow the action of error-prone DNA polymerases IV (DinB), II and V to make mutations during repair. Pol IV is implied to compete with and replace high-fidelity DNA polymerases at the DSB-repair replisome, causing mutagenesis. We report that up-regulated Pol IV is not sufficient for mutagenic break repair (MBR); damaged bases in the DNA are also required, and that in starvation-stressed cells, these are caused by reactive-oxygen species (ROS). First, MBR is reduced by either ROS-scavenging agents or constitutive activation of oxidative-damage responses, both of which reduce cellular ROS levels. The ROS promote MBR other than by causing DSBs, saturating mismatch repair, oxidizing proteins, or inducing the SOS response or the general stress response. We find that ROS drive MBR through oxidized guanines (8-oxo-dG) in DNA, in that overproduction of a glycosylase that removes 8-oxo-dG from DNA prevents MBR. Further, other damaged DNA bases can substitute for 8-oxo-dG because ROS-scavenged cells resume MBR if either DNA pyrimidine dimers or alkylated bases are induced. We hypothesize that damaged bases in DNA pause the replisome and allow the critical switch from high fidelity to error-prone DNA polymerases in the DSB-repair replisome, thus allowing MBR. The data imply that in addition to the indirect stress-response controlled switch to MBR, a direct cis-acting switch to MBR occurs independently of DNA breakage, caused by ROS oxidation of DNA potentially regulated by ROS regulators. Mutagenesis mechanisms upregulated by stress responses promote de novo antibiotic resistance and cross resistance in bacteria, anti-fungal-drug resistance in yeasts, and genome instability in cancer cells under hypoxic stress. Stress-induced mutagenesis is implicated as the main source of spontaneous mutagenesis that drives bacterial evolution, and may drive much of evolution generally. A widely useful model mechanism is mutagenic DNA break repair in Escherichia coli, in which activation of two stress responses allows error-prone DNA polymerase in the break-repair replisome and introduce misincorporations, later fixed as mutations. Both stress responses upregulate the error-prone mutagenic DNA polymerase Pol IV (DinB), suggesting that the regulation of mutagenesis to times of stress is accomplished by indirect gene upregulation, followed by DNA polymerase competition. This paper describes the discovery that the stress responses are not sufficient to allow mutagenesis caused by error-prone DNA polymerases in the break-repair replisome—damaged DNA bases must also be present—and that these are caused by reactive oxygen species in starving E. coli. We hypothesize that damaged bases may inhibit the progress of the highly processive and high fidelity replicative DNA polymerase, thus allowing the switch to error-prone DNA polymerases and mutagenesis. These findings suggest the possibility that the spontaneous mutation rate is regulated by the generation and removal of reactive oxygen, a very common byproduct of metabolism.
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影响因子：
14.9
作者：
Degtyareva NP;Heyburn L;Sterling J;Resnick MA;Gordenin DA;Doetsch PW
通讯作者：
Doetsch PW
影响因子：
11.4
作者：
Ballesteros, M;Fredriksson, Å;Nyström, T
通讯作者：
Nyström, T
DOI：
10.1007/bf00267420
发表时间：
1979-01-01
期刊：
MOLECULAR AND GENERAL GENETICS
影响因子：
--
作者：
CHLEBOWICZ, E;JACHYMCZYK, WJ
通讯作者：
JACHYMCZYK, WJ
DOI：
10.1016/0027-5107(90)90173-2
发表时间：
1990-07-01
期刊：
MUTATION RESEARCH
影响因子：
--
作者：
BERANEK, DT
通讯作者：
BERANEK, DT
大肠杆菌K-12的构造框架，单基因敲除突变体：Keio Collection。
影响因子：
9.9
作者：
通讯作者：
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