A NUCLEAR MUTATION DEFECTIVE IN MITOCHONDRIAL RECOMBINATION IN YEAST
A NUCLEAR MUTATION DEFECTIVE IN MITOCHONDRIAL RECOMBINATION IN YEAST
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DOI：
10.1002/j.1460-2075.1995.tb00081.x
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发表时间：
1995-08-15
期刊：
影响因子：
11.4
通讯作者：
SHIBATA, T
中科院分区：
文献类型：
--
作者：
LING, F;MAKISHIMA, F;SHIBATA, T
在真核生物的细胞核中，同源重组（杂交和基因转换）通常是遗传和DNA修复所必需的，偶尔也会引起DNA畸变。然而，同源重组在线粒体DNA的遗传和稳定性中的作用却知之甚少，线粒体DNA不断受到呼吸副产物活性氧的破坏。我们报告了第一个核隐性突变的例子，这表明同源重组在线粒体DNA的稳定遗传中起重要作用，为了检测这类突变，我们设计了一个新的程序，“单倍体线粒体杂交”，这使我们能够检查许多突变克隆。使用这种方法，我们检测了酿酒酵母的突变体，这些突变体显示出紫外线诱导呼吸缺陷突变的升高。我们获得了一个突变体，它在-内含子归巢和远藤上都有缺陷。我们发现突变细胞对线粒体DNA的维持具有温度敏感性，四组分析表明，紫外线诱导的呼吸缺陷突变、重组缺陷和温度敏感性升高都是由第XII染色体上的单个核突变（mhr1）引起的。突变体的多效性特征表明MHR1基因在线粒体DNA修复、重组和维持中起重要作用。
Homologous recombination (crossing over and gene conversion) is generally essential for heritage and DNA repair, and occasionally causes DNA aberrations, in nuclei of eukaryotes, However, little is known about the roles of homologous recombination in the inheritance and stability of mitochondrial DNA which is continuously damaged by reactive oxygen species, byproducts of respiration, Here, we report the first example of a nuclear recessive mutation which suggests an essential role for homologous recombination in the stable inheritance of mitochondrial DNA, For the detection of this class of mutants, we devised a novel procedure, 'mitochondrial crossing in haploid', which has enabled us to examine many mutant clones. Using this procedure, we examined mutants of Saccharomyces cerevisiae that showed an elevated UV induction of respiration-deficient mutations. We obtained a mutant that was defective in both the omega-intron homing and Endo.SceI-induced homologous gene conversion, We found that the mutant cells are temperature sensitive in the maintenance of mitochondrial DNA, A tetrad analysis indicated that elevated UV induction of respiration-deficient mutations, recombination deficiency and temperature sensitivity are all caused by a single nuclear mutation (mhr1) on chromosome XII. The pleiotropic characteristics of the mutant suggest an essential role for the MHR1 gene in DNA repair, recombination and the maintenance of DNA in mitochondria.