Caenorhabditis elegans par2.1/mtssb-1 is essential for mitochondrial DNA replication and its defect causes comprehensive transcriptional alterations including a hypoxia response
Caenorhabditis elegans par2.1/mtssb-1 is essential for mitochondrial DNA replication and its defect causes comprehensive transcriptional alterations including a hypoxia response
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DOI：
10.1016/j.yexcr.2007.08.015
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发表时间：
2008-01-01
影响因子：
3.7
通讯作者：
Higashitani, Atsushi
中科院分区：
文献类型：
--
作者：
Sugimoto, Tomoko;Mori, Chihiro;Higashitani, Atsushi
DNA 聚合酶 gamma 和 mtSSB 是 mtDNA 复制机制的关键组成部分。为了研究 mtDNA 复制缺陷的生物学影响，我们使用 RNAi 来消除秀丽隐杆线虫中假定的 mtSSB（par2.1）的基因。在之前的系统 RNAi 筛选中，该基因的下调并未导致任何明显缺陷的表型。在这里，我们连续几代人将靶向 par2.1 的 dsRNA 喂给线虫。 79% 的 F1 后代在喂养后 60-72 小时生长到成年，但完全不育，生殖细胞增殖停滞。线粒体DNA拷贝数和细胞学分析表明，不育雌雄同体的线粒体较少。这些结果表明 par2.1 主要通过 mtDNA 复制来发挥生殖细胞增殖的作用；因此我们将其命名为mtssb-1。全面的转录改变，包括依赖和独立于 hif-1 功能的缺氧反应诱导，是通过 mtssb-1 的 RNAi 耗竭而发生的。溴化乙锭治疗会损害 mtDNA 复制和转录，导致类似的转录改变。此外，在部分RNAi效应的作用下，可育后代中种系细胞凋亡的频率降低。这些表明秀丽隐杆线虫 mtssb-1 的 RNAi 消耗可用作线粒体功能障碍的模型系统。 (C) 2007 Elsevier Inc. 保留所有权利。
DNA polymerase gamma and mtSSB are key components of the mtDNA replication machinery. To study the biological influences of defects in mtDNA replication, we used RNAi to deplete the gene for a putative mtSSB, par2.1, in Caernorhabditis elegans. In previous systematic RNAi screens, downregulation of this gene has not caused any clearly defective phenotypes. Here, we continuously fed a dsRNA targeting par2.1 to C. elegans over generations. Seventy-nine percent of F1 progeny produced 60-72 h after feeding grew to adulthood but were completely sterile, with an arrest of germline cell proliferation. Analyses of mtDNA copy number and cell cytology indicated that the sterile hermaphrodites had fewer mitochondria. These results indicated that par2.1 essentially functions for germline cell proliferation through mtDNA replication; we therefore termed it mtssb-1. Comprehensive transcriptional alterations including hypoxia response induction dependent on and independent of hif-1 function, occurred by RNAi depletion of mtssb-1. Treatment with ethidium bromide, which impairs mtDNA replication and transcription, caused similar transcriptional alterations. In addition, the frequency of apoptosis in the germline cells was reduced in fertile progeny with a partial RNAi effect. These suggest that RNAi depletion of C. elegans mtssb-1 is useful as a model system of mitochondrial dysfunction. (C) 2007 Elsevier Inc. All rights reserved.