Recombination-dependent mtDNA partitioning:: in vivo role of Mhr1p to promote pairing of homologous DNA
Recombination-dependent mtDNA partitioning:: in vivo role of Mhr1p to promote pairing of homologous DNA
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DOI：
10.1093/emboj/cdf466
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发表时间：
2002-09-02
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;Shibata, T
酵母mhr1-1是一种线粒体DNA重组缺陷突变。大约一半的mhr1-1细胞在高温下生长时失去mtDNA。在这里，我们发现MHR1 -1在新生mtDNA分裂成芽时表现出缺陷，并且是编码线粒体基质蛋白的MHR1的碱基置换突变。我们发现Mhr1蛋白（Mhr1p）在体外具有将单链DNA与同源双链DNA配对形成异双关节的活性，而Mhr1 -1导致这种活性的丧失，说明其在同源mtDNA重组中的作用。虽然母细胞中的大部分mtDNA由从头到尾的串联体组成，但芽中超过一半的mtDNA以基因组大小的单体存在。mhr1-1 Deltacce1双突变细胞不维持任何mtDNA，表明mtDNA的维持严格依赖于重组功能。这些结果表明mtDNA的遗传机制类似于噬菌体DNA的复制和包装。
Yeast mhr1-1 was isolated as a defective mutation in mitochondrial DNA (mtDNA) recombination. About half of mhr1-1 cells lose mtDNA during growth at a higher temperature. Here, we show that mhr1-1 exhibits a defect in the partitioning of nascent mtDNA into buds and is a base-substitution mutation in MHR1 encoding a mitochondrial matrix protein. We found that the Mhr1 protein (Mhr1p) has activity to pair single-stranded DNA and homologous double-stranded DNA to form heteroduplex joints in vitro, and that mhr1-1 causes the loss of this activity, indicating its role in homologous mtDNA recombination. While the majority of the mtDNA in the mother cells consists of head-to-tail concatemers, more than half of the mtDNA in the buds exists as genome-sized monomers. The mhr1-1 Deltacce1 double mutant cells do not maintain any mtDNA, indicating the strict dependence of mtDNA maintenance on recombination functions. These results suggest a mechanism for mtDNA inheritance similar to that operating in the replication and packaging of phage DNA.