Kinesin-14 is Important for Chromosome Segregation During Mitosis and Meiosis in the Ciliate Tetrahymena thermophila.
Ciliates such as Tetrahymena thermophila have two distinct nuclei within one cell: the micronucleus that undergoes mitosis and meiosis and the macronucleus that undergoes amitosis, a type of nuclear division that does not involve a bipolar spindle, but still relies on intranuclear microtubules. Ciliates provide an opportunity for the discovery of factors that specifically contribute to chromosome segregation based on a bipolar spindle, by identification of factors that affect the micronuclear but not the macronuclear division. Kinesin-14 is a conserved minus-end directed microtubule motor that cross-links microtubules and contributes to the bipolar spindle sizing and organization. Here, we use homologous DNA recombination to knock out genes that encode kinesin-14 orthologues (KIN141, KIN142) in Tetrahymena. A loss of KIN141 led to severe defects in the chromosome segregation during both mitosis and meiosis but did not affect amitosis. A loss of KIN141 altered the shape of the meiotic spindle in a way consistent with the KIN141's contribution to the organization of the spindle poles. EGFP-tagged KIN141 preferentially accumulated at the spindle poles during the meiotic prophase and metaphase I. Thus, in ciliates, kinesin-14 is important for nuclear divisions that involve a bipolar spindle.
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.|Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, 371-8512, Japan.
Yasuharu
Y
Kushida
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.|Gunma University Initiative for Advanced Research, Gunma University, Maebashi, Gunma, 371-8511, Japan.
Masak
M
Takaine
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
Kentaro
K
Nakano
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
Toshiro
T
Sugai
Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA.
Krishna Kumar
KK
Vasudevan
Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA.
Mayukh
M
Guha
Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA.
Yu-Yang
YY
Jiang
Department of Cellular Biology, University of Georgia, Athens, Georgia, 30602, USA.
Jacek
J
Gaertig
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
Osamu
O
Numata
D000818:Animals; D002467:Cell Nucleus; D020090:Chromosome Segregation; D016798:Ciliophora / Q000166:cytology / Q000235:genetics*; D055786:Gene Knockout Techniques; D016547:Kinesins / Q000145:classification / Q000235:genetics* / Q000502:physiology* / Q000648:ultrastructure; D048648:Macronucleus; D008540:Meiosis; D049469:Meiotic Prophase I; D008677:Metaphase; D008870:Microtubules; D008938:Mitosis; D009154:Mutation; D010802:Phylogeny; D011994:Recombinant Proteins; D008941:Spindle Apparatus; D064047:Spindle Poles; D013768:Tetrahymena / Q000235:genetics; D016808:Tetrahymena thermophila / Q000166:cytology / Q000235:genetics* / Q000378:metabolism
D011994:Recombinant Proteins; D016547:Kinesins
Macronucleus; micronucleus; microtubule; minus-end motors; spindle