The Saccharomyces cerevisiae Homologues of Endonuclease III from Escherichia coli, Ntg1 and Ntg2, Are Both Required for Efficient Repair of Spontaneous and Induced Oxidative DNA Damage in Yeast
The Saccharomyces cerevisiae Homologues of Endonuclease III from Escherichia coli, Ntg1 and Ntg2, Are Both Required for Efficient Repair of Spontaneous and Induced Oxidative DNA Damage in Yeast
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大肠杆菌内切核酸酶 III 的酿酒酵母同源物 Ntg1 和 Ntg2 都是有效修复酵母自发和诱导氧化 DNA 损伤所必需的
DOI：
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发表时间：
1999
影响因子：
5.3
通讯作者：
M. Bjørås
中科院分区：
文献类型：
--
作者：
I. Alseth;L. Eide;Manuela Pirovano;Torbjørn Rognes;E. Seeberg;M. Bjørås
摘要 来自大肠杆菌的核酸内切酶 III 是一种普遍存在的 DNA 修复酶的原型，对于消除氧化嘧啶碱基损伤至关重要。酵母基因组计划揭示了酿酒酵母中存在两个基因 NTG1 和 NTG2，编码与核酸内切酶 III 相似的蛋白质。两者都含有高度保守的螺旋-发夹-螺旋基序，而只有一个 (Ntg2) 含有内切核酸酶 III 家族的特征性铁硫簇。我们通过突变体和酶分析以及基因表达和细胞内定位研究来表征这些基因功能。 NTG1和NTG2的靶向基因破坏产生的突变体相对于野生型大大增加了自发突变和过氧化氢诱导的突变频率，并且双突变体中的突变反应进一步增加。研究发现这两种酶都能高效去除 DNA 中的胸腺嘧啶乙二醇和 2,6-二氨基-4-羟基-5-N-甲基甲酰胺嘧啶 (faPy) 残基。然而，在紫外线照射的 DNA 上，Ntg2 的饱和浓度仅去除了 Ntg1 释放的胞嘧啶光产物的一半。相反，只有 Ntg2 才能有效去除 5-羟基胞嘧啶。这些酶似乎具有不同的反应模式，从 Ntg2 对受损 DNA 更高的亲和力以及 Ntg1 更有效地硼氢化物捕获到 DNA 中的脱碱基位点（尽管 DNA 结合有限）来判断。 Northern 印迹和启动子融合分析表明，NTG1 可通过细胞暴露于 DNA 损伤剂来诱导，而 NTG2 则为组成型表达。 Ntg2 似乎是一种核酶，而 Ntg1 既被分类到细胞核又被分类到线粒体。我们得出结论，NTG1 和 NTG2 的功能对于消除酵母中的氧化 DNA 损伤都很重要。
ABSTRACT Endonuclease III from Escherichia coli is the prototype of a ubiquitous DNA repair enzyme essential for the removal of oxidized pyrimidine base damage. The yeast genome project has revealed the presence of two genes in Saccharomyces cerevisiae,NTG1 and NTG2, encoding proteins with similarity to endonuclease III. Both contain the highly conserved helix-hairpin-helix motif, whereas only one (Ntg2) harbors the characteristic iron-sulfur cluster of the endonuclease III family. We have characterized these gene functions by mutant and enzyme analysis as well as by gene expression and intracellular localization studies. Targeted gene disruption of NTG1 and NTG2produced mutants with greatly increased spontaneous and hydrogen peroxide-induced mutation frequency relative to the wild type, and the mutation response was further increased in the double mutant. Both enzymes were found to remove thymine glycol and 2,6-diamino-4-hydroxy-5-N-methylformamidopyrimidine (faPy) residues from DNA with high efficiency. However, on UV-irradiated DNA, saturating concentrations of Ntg2 removed only half of the cytosine photoproducts released by Ntg1. Conversely, 5-hydroxycytosine was removed efficiently only by Ntg2. The enzymes appear to have different reaction modes, as judged from much higher affinity of Ntg2 for damaged DNA and more efficient borhydride trapping of Ntg1 to abasic sites in DNA despite limited DNA binding. Northern blot and promoter fusion analysis showed that NTG1 is inducible by cell exposure to DNA-damaging agents, whereas NTG2 is constitutively expressed. Ntg2 appears to be a nuclear enzyme, whereas Ntg1 was sorted both to the nucleus and to the mitochondria. We conclude that functions of both NTG1 and NTG2 are important for removal of oxidative DNA damage in yeast.
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影响因子：
3.8
作者：
Rezaee M;Alizadeh E;Hunting D;Sanche L
通讯作者：
Sanche L
DOI：
10.1073/pnas.91.14.6609
发表时间：
1994-07-05
影响因子：
11.1
作者：
FEIG, DI;SOWERS, LC;LOEB, LA
通讯作者：
LOEB, LA
胸腺嘧啶乙二醇在选择性抑制氧化 DNA 模板上的 DNA 合成中可能发挥的作用。
影响因子：
11.2
作者：
Rouet,P;Essigmann,JM
通讯作者：
Essigmann,JM
影响因子：
2.9
作者：
MELAMEDE, RJ;HATAHET, Z;WALLACE, SS
通讯作者：
WALLACE, SS
影响因子：
14.9
作者：
IDE, H;KOW, YW;WALLACE, SS
通讯作者：
WALLACE, SS