scholarly journals Mcp5, a meiotic cell cortex protein, is required for nuclear movement mediated by dynein and microtubules in fission yeast

2006 ◽  
Vol 173 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Takamune T. Saito ◽  
Daisuke Okuzaki ◽  
Hiroshi Nojima
Keyword(s):  
Fission Yeast ◽  
Meiotic Prophase ◽  
Coiled Coil ◽  
Cell Cortex ◽  
Ph Domain ◽  
Nuclear Movement ◽  
Recombination Rates ◽  
Homologous Chromosome Pairing ◽  
Cortical Localization ◽  
Pulling Force

During meiotic prophase I of the fission yeast Schizosaccharomyces pombe, oscillatory nuclear movement occurs. This promotes homologous chromosome pairing and recombination and involves cortical dynein, which plays a pivotal role by generating a pulling force with the help of an unknown dynein anchor. We show that Mcp5, the homologue of the budding yeast dynein anchor Num1, may be this putative dynein anchor. mcp5+ is predominantly expressed during meiotic prophase, and GFP-Mcp5 localizes at the cell cortex. Moreover, the mcp5Δ strain lacks the oscillatory nuclear movement. Accordingly, homologous pairing and recombination rates of the mcp5Δ strain are significantly reduced. Furthermore, the cortical localization of dynein heavy chain 1 appears to be reduced in mcp5Δ cells. Finally, the full function of Mcp5 requires its coiled-coil and pleckstrin homology (PH) domains. Our results suggest that Mcp5 localizes at the cell cortex through its PH domain and functions as a dynein anchor, thereby facilitating nuclear oscillation.

scholarly journals A Cytoplasmic Dynein Heavy Chain Is Required for Oscillatory Nuclear Movement of Meiotic Prophase and Efficient Meiotic Recombination in Fission Yeast

1999 ◽  
Vol 145 (6) ◽  
pp. 1233-1250 ◽  
Author(s):  
Ayumu Yamamoto ◽  
Robert R. West ◽  
J. Richard McIntosh ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Heavy Chain ◽  
Meiotic Recombination ◽  
Meiotic Prophase ◽  
Fluorescent Protein ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Nuclear Movement ◽  
Homologous Chromosomes ◽  
Dynein Heavy Chain

Meiotic recombination requires pairing of homologous chromosomes, the mechanisms of which remain largely unknown. When pairing occurs during meiotic prophase in fission yeast, the nucleus oscillates between the cell poles driven by astral microtubules. During these oscillations, the telomeres are clustered at the spindle pole body (SPB), located at the leading edge of the moving nucleus and the rest of each chromosome dangles behind. Here, we show that the oscillatory nuclear movement of meiotic prophase is dependent on cytoplasmic dynein. We have cloned the gene encoding a cytoplasmic dynein heavy chain of fission yeast. Most of the cells disrupted for the gene show no gross defect during mitosis and complete meiosis to form four viable spores, but they lack the nuclear movements of meiotic prophase. Thus, the dynein heavy chain is required for these oscillatory movements. Consistent with its essential role in such nuclear movement, dynein heavy chain tagged with green fluorescent protein (GFP) is localized at astral microtubules and the SPB during the movements. In dynein-disrupted cells, meiotic recombination is significantly reduced, indicating that the dynein function is also required for efficient meiotic recombination. In accordance with the reduced recombination, which leads to reduced crossing over, chromosome missegregation is increased in the mutant. Moreover, both the formation of a single cluster of centromeres and the colocalization of homologous regions on a pair of homologous chromosomes are significantly inhibited in the mutant. These results strongly suggest that the dynein-driven nuclear movements of meiotic prophase are necessary for efficient pairing of homologous chromosomes in fission yeast, which in turn promotes efficient meiotic recombination.

Characterization of fission yeast meiotic mutants based on live observation of meiotic prophase nuclear movement

Chromosoma ◽  
2000 ◽  
Vol 109 (1-2) ◽  
pp. 103-109 ◽  
Author(s):  
Yasushi Hiraoka ◽  
Da-Qiao Ding ◽  
Ayumu Yamamoto ◽  
Chihiro Tsutsumi ◽  
Yuji Chikashige
Keyword(s):  
Fission Yeast ◽  
Meiotic Prophase ◽  
Nuclear Movement ◽  
Meiotic Mutants

scholarly journals Dynamic Behavior of Microtubules during Dynein-dependent Nuclear Migrations of Meiotic Prophase in Fission Yeast

2001 ◽  
Vol 12 (12) ◽  
pp. 3933-3946 ◽  
Author(s):  
Ayumu Yamamoto ◽  
Chihiro Tsutsumi ◽  
Hiroaki Kojima ◽  
Kazuhiro Oiwa ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Dynamic Behavior ◽  
Meiotic Prophase ◽  
Fluorescent Protein ◽  
Cortical Microtubule ◽  
Spindle Pole Body ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Microtubule Assembly ◽  
Cell Cortex

During meiotic prophase in fission yeast, the nucleus migrates back and forth between the two ends of the cell, led by the spindle pole body (SPB). This nuclear oscillation is dependent on astral microtubules radiating from the SPB and a microtubule motor, cytoplasmic dynein. Here we have examined the dynamic behavior of astral microtubules labeled with the green fluorescent protein during meiotic prophase with the use of optical sectioning microscopy. During nuclear migrations, the SPB mostly follows the microtubules that extend toward the cell cortex. SPB migrations start when these microtubules interact with the cortex and stop when they disappear, suggesting that these microtubules drive nuclear migrations. The microtubules that are followed by the SPB often slide along the cortex and are shortened by disassembly at their ends proximal to the cortex. In dynein-mutant cells, where nuclear oscillations are absent, the SPB never migrates by following microtubules, and microtubule assembly/disassembly dynamics is significantly altered. Based on these observations, together with the frequent accumulation of dynein at a cortical site where the directing microtubules interact, we propose a model in which dynein drives nuclear oscillation by mediating cortical microtubule interactions and regulating the dynamics of microtubule disassembly at the cortex.

scholarly journals The 14-kDa Dynein Light Chain-Family Protein Dlc1 Is Required for Regular Oscillatory Nuclear Movement and Efficient Recombination during Meiotic Prophase in Fission Yeast

2002 ◽  
Vol 13 (3) ◽  
pp. 930-946 ◽  
Author(s):  
Futaba Miki ◽  
Koei Okazaki ◽  
Mizuki Shimanuki ◽  
Ayumu Yamamoto ◽  
Yasushi Hiraoka ◽  
...  
Keyword(s):  
Light Chain ◽  
Meiotic Prophase ◽  
Fluorescent Protein ◽  
Spindle Pole Body ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Cell Cortex ◽  
Dynein Light Chain ◽  
Nuclear Movement ◽  
Green Fluorescent

A Schizosaccharomyces pombe spindle pole body (SPB) protein interacts in a two-hybrid system with Dlc1, which belongs to the 14-kDa Tctex-1 dynein light chain family. Green fluorescent protein-tagged Dlc1 accumulated at the SPB throughout the life cycle. During meiotic prophase, Dlc1 was present along astral microtubules and microtubule-anchoring sites on the cell cortex, reminiscent of the cytoplasmic dynein heavy chain Dhc1. In a dlc1-null mutant, Dhc1-dependent nuclear movement in meiotic prophase became irregular in its duration and direction. Dhc1 protein was displaced from the cortex anchors and the formation of microtubule bundle(s) that guide nuclear movement was impaired in the mutant. Meiotic recombination in the dlc1 mutant was reduced to levels similar to that in the dhc1 mutant. Dlc1 and Dhc1 also have roles in karyogamy and rDNA relocation during the sexual phase. Strains mutated in both the dlc1 and dhc1loci displayed more severe defects in recombination, karyogamy, and sporulation than in either single mutant alone, suggesting that Dlc1 is involved in nuclear events that are independent of Dhc1. S. pombe contains a homolog of the 8-kDa dynein light chain, Dlc2. This class of dynein light chain, however, is not essential in either the vegetative or sexual phases.

scholarly journals Spindle pole body components are reorganized during fission yeast meiosis

2012 ◽  
Vol 23 (10) ◽  
pp. 1799-1811 ◽  
Author(s):  
Midori Ohta ◽  
Masamitsu Sato ◽  
Masayuki Yamamoto
Keyword(s):  
Fission Yeast ◽  
Meiotic Prophase ◽  
Spindle Pole Body ◽  
Mitotic Cell ◽  
Spindle Pole ◽  
Nuclear Movement ◽  
Pole Body ◽  
Proper Number ◽  
Body Components ◽  
Yeast Meiosis

During meiosis, the centrosome/spindle pole body (SPB) must be regulated in a manner distinct from that of mitosis to achieve a specialized cell division that will produce gametes. In this paper, we demonstrate that several SPB components are localized to SPBs in a meiosis-specific manner in the fission yeast Schizosaccharomyces pombe. SPB components, such as Cut12, Pcp1, and Spo15, which stay on the SPB during the mitotic cell cycle, disassociate from the SPB during meiotic prophase and then return to the SPB immediately before the onset of meiosis I. Interestingly, the polo kinase Plo1, which normally localizes to the SPB during mitosis, is excluded from them in meiotic prophase, when meiosis-specific, horse-tail nuclear movement occurs. We found that exclusion of Plo1 during this period was essential to properly remodel SPBs, because artificial targeting of Plo1 to SPBs resulted in an overduplication of SPBs. We also found that the centrin Cdc31 was required for meiotic SPB remodeling. Thus Plo1 and a centrin play central roles in the meiotic SPB remodeling, which is essential for generating the proper number of meiotic SPBs and, thereby provide unique characteristics to meiotic divisions.

scholarly journals Bqt2p is essential for initiating telomere clustering upon pheromone sensing in fission yeast

2006 ◽  
Vol 173 (6) ◽  
pp. 845-851 ◽  
Author(s):  
Xie Tang ◽  
Ye Jin ◽  
W. Zacheus Cande
Keyword(s):  
Fission Yeast ◽  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Homologous Chromosome ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Meiotic Progression ◽  
Pole Body ◽  
Homologous Chromosome Pairing

The telomere bouquet, i.e., telomere clustering on the nuclear envelope (NE) during meiotic prophase, is thought to promote homologous chromosome pairing. Using a visual screen, we identified bqt2/im295, a mutant that disrupts telomere clustering in fission yeast. Bqt2p is required for linking telomeres to the meiotic spindle pole body (SPB) but not for attachment of telomeres or the SPB to the NE. Bqt2p is expressed upon pheromone sensing and colocalizes thereafter to Sad1p, an SPB protein. This localization only depends on Bqt1p, not on other identified proteins required for telomere clustering. Upon pheromone sensing, generation of Sad1p foci next to telomeres depends on Bqt2p. However, depletion of Bqt2p from the SPB is dispensable for dissolving the telomere bouquet at the end of meiotic prophase. Therefore, telomere bouquet formation requires Bqt2p as a linking component and is finely regulated during meiotic progression.

scholarly journals Kinesin-6 Klp9 plays motor-dependent and -independent roles in collaboration with Kinesin-5 Cut7 and the microtubule crosslinker Ase1 in fission yeast

2018 ◽  
Author(s):  
Masashi Yukawa ◽  
Masaki Okazaki ◽  
Yasuhiro Teratani ◽  
Ken’ya Furuta ◽  
Takashi Toda
Keyword(s):  
Fission Yeast ◽  
Structural Integrity ◽  
Coiled Coil ◽  
Cell Cortex ◽  
Mitotic Spindles ◽  
Motor Region ◽  
Spindle Microtubules ◽  
Spindle Elongation ◽  
Synthetically Lethal ◽  
Anaphase B

ABSTRACTBipolar mitotic spindles play a critical part in accurate chromosome segregation. During late mitosis, spindle microtubules undergo drastic elongation towards the cell cortex in a process called anaphase B. Two kinesin motors, Kinesin-5 and Kinesin-6, are thought to generate outward forces to drive spindle elongation, and the microtubule crosslinker Ase1/PRC1 maintains structural integrity of antiparallel microtubules. However, how these three proteins orchestrate this process remains unknown. Here we explore the functional interplay among fission yeast Kinesin-5/Cut7, Kinesin-6/Klp9 and Ase1. Using total internal reflection fluorescence microscopy, we show that Klp9 is a processive plus end-directed motor. klp9Δase1Δ is synthetically lethal. Surprisingly, this lethality is not ascribable to the defective motor activity of Klp9; instead, it is dependent upon an NLS and coiled coil domains within the non-motor region. We isolated a cut7 mutant (cut7-122) that displays temperature sensitivity only in the absence of Klp9. Interestingly, cut7-122 is impaired specifically in late mitotic stages. cut7-122klp9Δ double mutant cells exhibit additive defects in spindle elongation. Together, we propose that Klp9 plays dual roles during anaphase B; one is motor-dependent that collaborates with Cut7 in force generation, while the other is motor-independent and ensures structural integrity of spindle microtubules together with Ase1.

scholarly journals Dynamics of Homologous Chromosome Pairing during Meiotic Prophase in Fission Yeast

2004 ◽  
Vol 6 (3) ◽  
pp. 329-341 ◽  
Author(s):  
Da-Qiao Ding ◽  
Ayumu Yamamoto ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Homologous Chromosome ◽  
Homologous Chromosome Pairing

Oscillatory nuclear movement in fission yeast meiotic prophase is driven by astral microtubules, as revealed by continuous observation of chromosomes and microtubules in living cells

1998 ◽  
Vol 111 (6) ◽  
pp. 701-712 ◽  
Author(s):  
D.Q. Ding ◽  
Y. Chikashige ◽  
T. Haraguchi ◽  
Y. Hiraoka
Keyword(s):  
Fission Yeast ◽  
Meiotic Prophase ◽  
Fluorescent Protein ◽  
Dynamic Instability ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Living Cells ◽  
Continuous Observation ◽  
Nuclear Movement ◽  
Pole Body

Using a computerized fluorescence microscope system to observe fluorescently stained cellular structures in vivo, we have examined the dynamics of chromosomes and microtubules during the process of meiosis in the fission yeast Schizosaccharomyces pombe. Fission yeast meiotic prophase is characterized by a distinctive type of nuclear movement that is led by telomeres clustered at the spindle-pole body (the centrosome-equivalent structure in fungi): the nucleus oscillates back and forth along the cell axis, moving continuously between the two ends of the cell for some hours prior to the meiotic divisions. To obtain a dynamic view of this oscillatory nuclear movement in meiotic prophase, we visualized microtubules and chromosomes in living cells using jellyfish green fluorescent protein fused with alpha-tubulin and a DNA-specific fluorescent dye, Hoechst 33342, respectively. Continuous observation of chromosomes and microtubules in these cells demonstrated that the oscillatory nuclear movement is mediated by dynamic reorganization of astral microtubules originating from the spindle-pole body. During each half-oscillatory period, the microtubules extending rearward from the leading edge of the nucleus elongate to drive the nucleus to one end of the cell. When the nucleus reversed direction, its motion during the second half of the oscillation was not driven by the same microtubules that drove its motion during the first half, but rather by newly assembled microtubules. Reversible inhibition of nuclear movement by an inhibitor of microtubule polymerization, thiabendazole, confirmed the involvement of astral microtubules in oscillatory nuclear movement. The speed of the movement fluctuated within a range 0 to 15 micron/minute, with an average of about 5 microm/minute. We propose a model in which the oscillatory nuclear movement is mediated by dynamic instability and selective stabilization of astral microtubules.

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