Centrioles are composed of long-lived microtubules arranged in nine triplets. However, the contribution of triplet microtubules to mammalian centriole formation and stability is unknown. Little is known of the mechanism of triplet microtubule formation, but experiments in unicellular eukaryotes indicate that delta-tubulin and epsilon-tubulin, two less-studied tubulin family members, are required. Here, we report that centrioles in delta-tubulin and epsilon-tubulin null mutant human cells lack triplet microtubules and fail to undergo centriole maturation. These aberrant centrioles are formed de novo each cell cycle, but are unstable and do not persist to the next cell cycle, leading to a futile cycle of centriole formation and disintegration. Disintegration can be suppressed by paclitaxel treatment. Delta-tubulin and epsilon-tubulin physically interact, indicating that these tubulins act together to maintain triplet microtubules and that these are necessary for inheritance of centrioles from one cell cycle to the next.

中文翻译：

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人类细胞中稳定的中心粒形成和遗传需要中心粒三重微管

中心粒由排列成九个三联体的长寿微管组成。然而，三联体微管对哺乳动物中心粒形成和稳定性的贡献尚不清楚。关于三联体微管形成的机制知之甚少，但在单细胞真核生物中的实验表明需要 delta-微管蛋白和 epsilon-微管蛋白这两个研究较少的微管蛋白家族成员。在这里，我们报告 delta-微管蛋白和 epsilon-微管蛋白空突变人类细胞中的中心粒缺乏三联体微管并且无法进行中心粒成熟。这些异常的中心粒在每个细胞周期从头形成，但不稳定，不会持续到下一个细胞周期，导致中心粒形成和分解的无效循环。紫杉醇治疗可以抑制崩解。