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Subcellular localization and role of Ran1 in Tetrahymena thermophila amitotic macronucleus
Author(s) -
Liang Haixia,
Xu Jing,
Zhao Dan,
Tian Huaru,
Yang Xuxia,
Liang Aihua,
Wang Wei
Publication year - 2012
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2012.08634.x
Subject(s) - macronucleus , tetrahymena , microbiology and biotechnology , ran , biology , mitosis , microtubule , small gtpase , spindle pole body , spindle apparatus , gtpase , cell division , tubulin , genetics , cell , signal transduction , ciliate
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 .