Biochemical properties of Caenorhabditis elegans HMG-5, a regulator of mitochondrial DNA.
Biochemical properties of Caenorhabditis elegans HMG-5, a regulator of mitochondrial DNA.
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DOI：
10.1093/jb/mvr008
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发表时间：
2011-05
影响因子：
2.7
通讯作者：
M. Sumitani;K. Kasashima;J. Matsugi;H. Endo
中科院分区：
文献类型：
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作者：
M. Sumitani;K. Kasashima;J. Matsugi;H. Endo
秀丽隐杆线虫HMG-5基因由F45E4.9编码，含有两个高迁移率族（HMG）盒结构域，与哺乳动物线粒体转录因子A（TFAM）序列相似。在这项研究中，使用浸泡RNA干扰，我们发现，敲低HMG-5减少了P0雌雄同体的mtDNA的量，这表明它是哺乳动物TFAM的功能直系同源物。我们还研究了HMG-5在哺乳动物细胞和体外的生化特性。我们发现，HMG-5定位于人培养细胞的线粒体，并包括在NP-40不溶性部分，其中mtDNA和TFAM富集。通过免疫沉淀分析，发现HMG-5与细胞中的人线粒体DNA（mtDNA）结合。体外结合实验表明HMG-5与C.线虫mtDNA和质粒DNA，表明它是一种非特异性DNA结合蛋白。此外，发现HMG-5可以与自身相互作用。这些结果表明，HMG 5作为类核因子与哺乳动物TFAM具有相似的生化特性。HMG-5可能是研究多细胞生物mtDNA代谢的一个很好的候选者。
Caenorhabditis elegans HMG-5, which is encoded by F45E4.9, contains two high mobility group (HMG) box domains and shows sequence similarity with mammalian mitochondrial transcription factor A (TFAM). In this study, using soaking RNA interference, we found that knockdown of HMG-5 reduced the amount of mtDNA in P0 hermaphrodites, suggesting it as functional orthologue of mammalian TFAM. We also examined the biochemical property of HMG-5 in mammalian cells and in vitro. We found that HMG-5 localized to the mitochondria in human cultured cells and was included in the NP-40-insoluble fraction in which mtDNA and TFAM were enriched. By immunoprecipitation analysis, HMG-5 was found to associate with human mitochondrial DNA (mtDNA) in the cells. In vitro binding experiment also showed that HMG-5 binds to C. elegans mtDNA and plasmid DNA, indicating its feature as a non-specific DNA-binding protein. Furthermore, it was found that HMG-5 can interact with itself. These results demonstrate that HMG5 shares similar biochemical properties with mammalian TFAM as a nucleoid factor. HMG-5 could be a good candidate for investigating mtDNA metabolism in multicellular organisms.