Electron tomography of the microtubule cytoskeleton in multinucleated hyphae of Ashbya gossypii
Electron tomography of the microtubule cytoskeleton in multinucleated hyphae of Ashbya gossypii
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DOI：
10.1242/jcs.111005
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发表时间：
2012-12-01
影响因子：
4
通讯作者：
Antony, Claude
中科院分区：
文献类型：
--
作者：
Gibeaux, Romain;Lang, Claudia;Antony, Claude
我们报道了指导棉阿什比亚菌丝中多核迁移模式的机制基础。使用电子断层扫描，我们重建了三个尖端区域的细胞质微管（cMT）细胞骨架，共有 13 个核，以及四个有丝分裂核的纺锤体微管。每个纺锤体极体（SPB）成核三个cMT，并且大多数超过一定长度的cMT根据其正端结构生长。长 cMT 沿着皮层紧密排列数微米，可能标记了动力蛋白对细胞核产生拉力的区域。没有观察到从相邻核发出的 cMT 之间的紧密接近。大多数细胞核携带重复的并排 SPB，它们平均发出 6 个 cMT，在大多数情况下相对于菌丝生长轴方向相反。这种 cMT 阵列解释了为什么许多原子核会进行短程来回运动。只有偶尔，所有六个 cMT 才会朝一个方向定向，这是远程核旁路的先决条件。有丝分裂后，子核携带一个带有三个 cMT 的 SPB。所有三个 cMT 朝一个方向定向的可能性增加解释了在这些原子核中观察到的高核旁路率。研究发现，棉A. gossypii 有丝分裂纺锤体在核微管（nMT）数量、长度分布和三维组织方面与酿酒酵母有丝分裂纺锤体结构相似，尽管这两种生物体在染色体数量上存在显着差异。我们的结果表明，棉曲霉的每个动粒上有两个 nMT，而不是像酿酒酵母那样只有一个 nMT。
We report the mechanistic basis guiding the migration pattern of multiple nuclei in hyphae of Ashbya gossypii. Using electron tomography, we reconstructed the cytoplasmic microtubule (cMT) cytoskeleton in three tip regions with a total of 13 nuclei and also the spindle microtubules of four mitotic nuclei. Each spindle pole body (SPB) nucleates three cMTs and most cMTs above a certain length grow according to their plus-end structure. Long cMTs closely align for several microns along the cortex, presumably marking regions where dynein generates pulling forces on nuclei. Close proximity between cMTs emanating from adjacent nuclei was not observed. The majority of nuclei carry duplicated side-by-side SPBs, which together emanate an average of six cMTs, in most cases in opposite orientation with respect to the hyphal growth axis. Such cMT arrays explain why many nuclei undergo short-range back and forth movements. Only occasionally do all six cMTs orient in one direction, a precondition for long-range nuclear bypassing. Following mitosis, daughter nuclei carry a single SPB with three cMTs. The increased probability that all three cMTs orient in one direction explains the high rate of nuclear bypassing observed in these nuclei. The A. gossypii mitotic spindle was found to be structurally similar to that of Saccharomyces cerevisiae in terms of nuclear microtubule (nMT) number, length distribution and three-dimensional organization even though the two organisms differ significantly in chromosome number. Our results suggest that two nMTs attach to each kinetochore in A. gossypii and not only one nMT like in S. cerevisiae.