Nuclear shape, growth and integrity in the closed mitosis of fission yeast depend on the Ran-GTPase system, the spindle pole body and the endoplasmic reticulum

Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

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Two-hybrid search for proteins that interact with Sad1 and Kms1, two membrane-bound components of the spindle pole body in fission yeast

Molecular Genetics and Genomics ◽

10.1007/s00438-003-0938-8 ◽

2003 ◽

Vol 270 (6) ◽

pp. 449-461 ◽

Cited By ~ 74

Author(s):

F. Miki ◽

A. Kurabayashi ◽

Y. Tange ◽

K. Okazaki ◽

M. Shimanuki ◽

...

Keyword(s):

Fission Yeast ◽

Spindle Pole Body ◽

Spindle Pole ◽

Hybrid Search ◽

Pole Body ◽

Membrane Bound ◽

Two Hybrid

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Cut1/separase C-terminus affects spindle pole body positioning in interphase of fission yeast: pointed nuclear formation

Genes to Cells ◽

10.1046/j.1365-2443.2002.00586.x ◽

2002 ◽

Vol 7 (11) ◽

pp. 1113-1124 ◽

Cited By ~ 9

Author(s):

Takahiro Nakamura ◽

Koji Nagao ◽

Yukinobu Nakaseko ◽

Mitsuhiro Yanagida

Keyword(s):

Fission Yeast ◽

Spindle Pole Body ◽

Spindle Pole ◽

Pole Body ◽

C Terminus ◽

Body Positioning

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Spindle Pole Body Duplication in Fission Yeast Occurs at the G1/S Boundary but Maturation Is Blocked until Exit from S by an Event Downstream of Cdc10+

Molecular Biology of the Cell ◽

10.1091/mbc.e04-03-0255 ◽

2004 ◽

Vol 15 (12) ◽

pp. 5219-5230 ◽

Cited By ~ 31

Author(s):

Satoru Uzawa ◽

Fei Li ◽

Ye Jin ◽

Kent L. McDonald ◽

Michael B. Braunfeld ◽

...

Keyword(s):

Fission Yeast ◽

Spindle Pole Body ◽

Specific Inhibitor ◽

Spindle Pole ◽

Feedback Mechanism ◽

G1 Arrest ◽

Restrictive Temperature ◽

Permissive Temperature ◽

Pole Body ◽

In Cells

The regulation and timing of spindle pole body (SPB) duplication and maturation in fission yeast was examined by transmission electron microscopy. When cells are arrested at G1 by nitrogen starvation, the SPB is unduplicated. On release from G1, the SPBs were duplicated after 1–2 h. In cells arrested at S by hydroxyurea, SPBs are duplicated but not mature. In G1 arrest/release experiments with cdc2.33 cells at the restrictive temperature, SPBs remained single, whereas in cells at the permissive temperature, SPBs were duplicated. In cdc10 mutant cells, the SPBs seem not only to be duplicated but also to undergo partial maturation, including invagination of the nuclear envelope underneath the SPB. There may be an S-phase–specific inhibitor of SPB maturation whose expression is under control of cdc10+. This model was examined by induction of overreplication of the genome by overexpression of rum1p or cdc18p. In cdc18p-overexpressing cells, the SPBs are duplicated but not mature, suggesting that cdc18p is one component of this feedback mechanism. In contrast, cells overexpressing rum1p have large, deformed SPBs accompanied by other features of maturation and duplication. We propose a feedback mechanism for maturation of the SPB that is coupled with exit from S to trigger morphological changes.

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Targeting Alp7/TACC to the spindle pole body is essential for mitotic spindle assembly in fission yeast

FEBS Letters ◽

10.1016/j.febslet.2014.06.027 ◽

2014 ◽

Vol 588 (17) ◽

pp. 2814-2821 ◽

Cited By ~ 12

Author(s):

Ngang Heok Tang ◽

Naoyuki Okada ◽

Chii Shyang Fong ◽

Kunio Arai ◽

Masamitsu Sato ◽

...

Keyword(s):

Fission Yeast ◽

Mitotic Spindle ◽

Spindle Pole Body ◽

Spindle Assembly ◽

Spindle Pole ◽

Pole Body ◽

Mitotic Spindle Assembly

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Cytokinetic actomyosin ring formation and septation in fission yeast are dependent on the full recruitment of the polo-like kinase Plo1 to the spindle pole body and a functional spindle assembly checkpoint

Journal of Cell Science ◽

10.1242/jcs.00031 ◽

2002 ◽

Vol 115 (18) ◽

pp. 3575-3586 ◽

Cited By ~ 23

Author(s):

D. P. Mulvihill

Keyword(s):

Fission Yeast ◽

Spindle Assembly Checkpoint ◽

Spindle Pole Body ◽

Spindle Assembly ◽

Spindle Pole ◽

Ring Formation ◽

Pole Body

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Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e13-11-0699 ◽

2014 ◽

Vol 25 (18) ◽

pp. 2735-2749 ◽

Cited By ~ 22

Author(s):

I-Ju Lee ◽

Ning Wang ◽

Wen Hu ◽

Kersey Schott ◽

Jürg Bähler ◽

...

Keyword(s):

Cell Cycle ◽

Cell Division ◽

Fission Yeast ◽

Budding Yeast ◽

Binding Protein ◽

Spindle Pole Body ◽

Spindle Pole ◽

Centrosome Duplication ◽

Pole Body ◽

The Individual

Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.

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