Subcellular localization and role of Ran1 in Tetrahymena thermophila amitotic macronucleus
Subcellular localization and role of Ran1 in Tetrahymena thermophila amitotic macronucleus
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DOI：
10.1111/j.1742-4658.2012.08634.x
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
Haixia Liang;Jing Xu;Dan Zhao;Hua Tian;Xuxia Yang;A. Liang;Wei Wang
中科院分区：
文献类型：
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作者：
Haixia Liang;Jing Xu;Dan Zhao;Hua Tian;Xuxia Yang;A. Liang;Wei Wang
无丝分裂是一种常见于纤毛虫、真菌和某些动植物细胞的直接细胞分裂方式。在无丝分裂过程中，尽管缺乏双极纺锤体，但核内微管被重组成特定的阵列，这些阵列有助于细胞核的分离。然而，无丝分裂的调控尚不清楚。在这里，我们专注于定位和有丝分裂纺锤体组装调节：Ran GTfl（Ran1）在大核无丝分裂在双核原生动物嗜热四膜虫的作用。HA标记的Ran1在四膜虫营养生长的整个细胞周期中定位于大核中，并且Ran1的辅助因子结合结构域有助于其大核定位。不完全体细胞敲除RAN1导致异常的大核内微管阵列形成，大核染色体的错误分离，并最终阻止大核增殖。当Ran1周期被Ran1T25 N（GDP结合的Ran1模拟物）或Ran1Q70 L（GTP结合的Ran1模拟物）过表达干扰时，大核内微管组装受到抑制或形成多微核细胞。这些结果表明，Ran GT3通路参与了一个专门的大核内微管网络的组装，并协调四膜虫的无丝分裂进程。
Amitosis, a direct method of cell division is common in ciliated protozoan, fungi and some animal and plant cells. During amitosis, intranuclear microtubules are reorganized into specified arrays which assist in separation of nucleus, despite lack of a bipolar spindle. However, the regulation of amitosis is not understood. Here, we focused on the localization and role of mitotic spindle assembly regulator: Ran GTPase (Ran1) in macronuclear amitosis in binucleated protozoan Tetrahymena thermophila. HA‐tagged Ran1 was localized in the macronucleus throughout the cell cycle of Tetrahymena during vegetative growth, and the accessory factor binding domains of Ran1 contributed to its macronuclear localization. Incomplete somatic knockout of RAN1 resulted in aberrant intramacronuclear microtubule array formation, missegregation of macronuclear chromosomes and ultimately blocked macronuclei proliferation. When the Ran1 cycle was perturbed by overexpression of Ran1T25N (GDP‐bound Ran1‐mimetic) or Ran1Q70L (GTP‐bound Ran1‐mimetic), intramacronuclear microtubule assembly was inhibited or multi‐micronucleate cells formed. These results suggest that Ran GTPase pathway is involved in assembly of a specialized intramacronuclear microtubule network and coordinates amitotic progression in Tetrahymena.