A high-order trans-membrane structural linkage is responsible for mitochondrial genome positioning and segregation by flagellar basal bodies in trypanosomes
A high-order trans-membrane structural linkage is responsible for mitochondrial genome positioning and segregation by flagellar basal bodies in trypanosomes
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DOI：
10.1091/mbc.e02-08-0525
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发表时间：
2003-05-01
影响因子：
3.3
通讯作者：
Gull, K
中科院分区：
文献类型：
--
作者：
Ogbadoyi, EO;Robinson, DR;Gull, K
在锥虫中，动质体内的大线粒体基因组与鞭毛基体物理连接，并在细胞生长期间被它们分离。导致这些现象的结构联系尚不清楚。我们已经开发了新的提取/固定协议，以表征参与动质体鞭毛附着和分离的链接。我们发现，三个特定的组件组成的结构，我们称之为三方附件复合物（TAC）。TAC包括一组连接基体与分化的线粒体外膜和内膜区的细丝，以及另一组连接分化的膜区的内面与动基体的线粒体内细丝。TAC和鞭毛-动质体DNA连接在整个细胞周期中持续存在，并在周期性的动质体DNA S期进行复制和重塑。这种对高阶跨膜连接的理解为锥虫线粒体基因组的空间位置及其分离机制提供了解释。此外，TAC的结构表明，它也可以在线粒体DNA的这种连锁质量的复制过程中发挥结构和载体作用。我们认为，这种复合物可能代表了一种极端的形式，更普遍地发生的细胞骨架/细胞骨架的相互作用。
In trypanosomes, the large mitochondrial genome within the kinetoplast is physically connected to the flagellar basal bodies and is segregated by them during cell growth. The structural linkage enabling these phenomena is unknown. We have developed novel extraction/fixation protocols to characterize the links involved in kinetoplast-flagellum attachment and segregation. We show that three specific components comprise a structure that we have termed the tripartite attachment complex (TAC). The TAC involves a set of filaments linking the basal bodies to a zone of differentiated outer and inner mitochondrial membranes and a further set of intramitochondrial filaments linking the inner face of the differentiated membrane zone to the kinetoplast. The TAC and flagellum-kinetoplast DNA connections are sustained throughout the cell cycle and are replicated and remodeled during the periodic kinetoplast DNA S phase. This understanding of the high-order trans-membrane linkage provides an explanation for the spatial position of the trypanosome mitochondrial genome and its mechanism of segregation. Moreover, the architecture of the TAC suggests that it may also function in providing a structural and vectorial role during replication of this catenated mass of mitochondrial DNA. We suggest that this complex may represent an extreme form of a more generally occurring mitochondrion/cytoskeleton interaction.