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.

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.

scholarly journals Dissociation of the Nuf2-Ndc80 Complex Releases Centromeres from the Spindle-Pole Body during Meiotic Prophase in Fission Yeast

2005 ◽  
Vol 16 (5) ◽  
pp. 2325-2338 ◽  
Author(s):  
Haruhiko Asakawa ◽  
Aki Hayashi ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Meiotic Prophase ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Mating Pheromone ◽  
Pole Body ◽  
Pheromone Signaling ◽  
Ndc80 Complex ◽  
Mutant Cells

In the fission yeast Schizosaccharomyces pombe, centromeres remain clustered at the spindle-pole body (SPB) during mitotic interphase. In contrast, during meiotic prophase centromeres dissociate from the SPB. Here we examined the behavior of centromere proteins in living meiotic cells of S. pombe. We show that the Nuf2-Ndc80 complex proteins (Nuf2, Ndc80, Spc24, and Spc25) disappear from the centromere in meiotic prophase when the centromeres are separated from the SPB. The centromere protein Mis12 also dissociates during meiotic prophase; however, Mis6 remains throughout meiosis. When cells are induced to meiosis by inactivation of Pat1 kinase (a key negative regulator of meiosis), centromeres remain associated with the SPB during meiotic prophase. However, inactivation of Nuf2 by a mutation causes the release of centromeres from the SPB in pat1 mutant cells, suggesting that the Nuf2-Ndc80 complex connects centromeres to the SPB. We further found that removal of the Nuf2-Ndc80 complex from the centromere and centromere-SPB dissociation are caused by mating pheromone signaling. Because pat1 mutant cells also show aberrant chromosome segregation in the first meiotic division and this aberration is compensated by mating pheromone signaling, dissociation of the Nuf2-Ndc80 complex may be associated with remodeling of the kinetochore for meiotic chromosome segregation.

scholarly journals Membrane proteins Bqt3 and -4 anchor telomeres to the nuclear envelope to ensure chromosomal bouquet formation

2009 ◽  
Vol 187 (3) ◽  
pp. 413-427 ◽  
Author(s):  
Yuji Chikashige ◽  
Miho Yamane ◽  
Kasumi Okamasa ◽  
Chihiro Tsutsumi ◽  
Tomoko Kojidani ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Fission Yeast ◽  
Nuclear Membrane ◽  
Meiotic Prophase ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Null Mutant ◽  
Vegetative Cells ◽  
Nuclear Membranes ◽  
Pole Body

In many organisms, telomeres cluster to form a bouquet arrangement of chromosomes during meiotic prophase. Previously, we reported that two meiotic proteins, Bqt1 and -2, are required for tethering telomeres to the spindle pole body (SPB) during meiotic prophase in fission yeast. This study has further identified two novel, ubiquitously expressed inner nuclear membrane (INM) proteins, Bqt3 and -4, which are required for bouquet formation. We found that in the absence of Bqt4, telomeres failed to associate with the nuclear membranes in vegetative cells and consequently failed to cluster to the SPB in meiotic prophase. In the absence of Bqt3, Bqt4 protein was degraded during meiosis, leading to a phenotype similar to that of the bqt4-null mutant. Collectively, these results show that Bqt4 anchors telomeres to the INM and that Bqt3 protects Bqt4 from protein degradation. Interestingly, the functional integrity of telomeres is maintained even when they are separated from the nuclear envelope in vegetative cells.

Pcp1/pericentrin controls the SPB number in fission yeast meiosis and ploidy homeostasis

2021 ◽  
Vol 221 (1) ◽  
Author(s):  
Qian Zhu ◽  
Zhaodi Jiang ◽  
Xiangwei He
Keyword(s):  
Cell Division ◽  
Sexual Reproduction ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Bipolar Spindle ◽  
Pole Body ◽  
Yeast Meiosis ◽  
Quantity Control

During sexual reproduction, the zygote must inherit exactly one centrosome (spindle pole body [SPB] in yeasts) from the gametes, which then duplicates and assembles a bipolar spindle that supports the subsequent cell division. Here, we show that in the fission yeast Schizosaccharomyces pombe, the fusion of SPBs from the gametes is blocked in polyploid zygotes. As a result, the polyploid zygotes cannot proliferate mitotically and frequently form supernumerary SPBs during subsequent meiosis, which leads to multipolar nuclear divisions and the generation of extra spores. The blockage of SPB fusion is caused by persistent SPB localization of Pcp1, which, in normal diploid zygotic meiosis, exhibits a dynamic association with the SPB. Artificially induced constitutive localization of Pcp1 on the SPB is sufficient to cause blockage of SPB fusion and formation of extra spores in diploids. Thus, Pcp1-dependent SPB quantity control is crucial for sexual reproduction and ploidy homeostasis in fission yeast.

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 Chromosomes Rein Back the Spindle Pole Body during Horsetail Movement in Fission Yeast Meiosis

2014 ◽  
Vol 39 (2) ◽  
pp. 93-100 ◽  
Author(s):  
Yuji Chikashige ◽  
Miho Yamane ◽  
Kasumi Okamasa ◽  
Chie Mori ◽  
Noriko Fukuta ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
Yeast Meiosis

Distinct nuclear and spindle pole body populations of cyclin–cdc2 in fission yeast

Nature ◽  
1990 ◽  
Vol 347 (6294) ◽  
pp. 680-682 ◽  
Author(s):  
Caroline E. Alfa ◽  
Bernard Ducommun ◽  
David Beach ◽  
Jeremy S. Hyams
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

Asymmetry of the spindle pole bodies and spg1p GAP segregation during mitosis in fission yeast

1999 ◽  
Vol 112 (14) ◽  
pp. 2313-2321 ◽  
Author(s):  
L. Cerutti ◽  
V. Simanis
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Mitotic Cell ◽  
Spindle Pole ◽  
The Other ◽  
Septum Formation ◽  
Spindle Pole Bodies ◽  
Interphase Cells ◽  
Early Mitosis

In the fission yeast Schizosaccharomyces pombe, the onset of septum formation is induced by a signal transduction network involving several protein kinases and a GTPase switch. One of the roles of the spg1p GTPase is to localise the cdc7p protein kinase to the poles of the mitotic spindle, from where the onset of septation is thought to be signalled at the end of mitosis. Immunofluorescence studies have shown that cdc7p is located on both spindle pole bodies early in mitosis, but only on one during the later stages of anaphase. This is mediated by inactivation of spg1p on one pole before the other. The GAP for spg1p is a complex of two proteins, cdc16p and byr4p. Localisation of cdc16p and byr4p by indirect immunofluorescence during the mitotic cell cycle showed that both proteins are present on the spindle pole body in interphase cells. During mitosis, byr4p is seen first on both poles of the spindle, then on only one. This occurs prior to cdc7p becoming asymmetric. In contrast, the signal due to cdc16p decreases to a low level during early mitosis, before being seen strongly on the same pole as byr4p. Double staining indicates that this is the opposite pole to that which retains cdc7p in late anaphase. Examination of the effect of inactivating cdc16p at various stages of the cell cycle suggests that cdc16p, together with cdc2p plays a role in restraining septum formation during interphase. The asymmetric inactivation of spg1p is mediated by recruitment of the cdc16p-byr4p GAP to one of the poles of the spindle before the other, and the asymmetry of the spindle pole bodies may be established early during mitosis. Moreover, the spindle pole bodies appear to be non-equivalent even after division has been completed.

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