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

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.

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A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e17-08-0497 ◽

2017 ◽

Vol 28 (25) ◽

pp. 3647-3659 ◽

Cited By ~ 23

Author(s):

Masashi Yukawa ◽

Tomoki Kawakami ◽

Masaki Okazaki ◽

Kazunori Kume ◽

Ngang Heok Tang ◽

...

Keyword(s):

Fission Yeast ◽

Chromosome Segregation ◽

Spindle Pole Body ◽

Spindle Assembly ◽

Spindle Pole ◽

Temperature Sensitive ◽

Bipolar Spindle ◽

Pole Body ◽

Cross Linker ◽

Spindle Elongation

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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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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A stable microtubule array drives fission yeast polarity reestablishment upon quiescence exit

The Journal of Cell Biology ◽

10.1083/jcb.201502025 ◽

2015 ◽

Vol 210 (1) ◽

pp. 99-113 ◽

Cited By ~ 12

Author(s):

Damien Laporte ◽

Fabien Courtout ◽

Benoît Pinson ◽

Jim Dompierre ◽

Bénédicte Salin ◽

...

Keyword(s):

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Actin Filament ◽

Molecular Model ◽

Spindle Pole Body ◽

Spindle Pole ◽

Microtubule Array ◽

Pole Body

Cells perpetually face the decision to proliferate or to stay quiescent. Here we show that upon quiescence establishment, Schizosaccharomyces pombe cells drastically rearrange both their actin and microtubule (MT) cytoskeletons and lose their polarity. Indeed, while polarity markers are lost from cell extremities, actin patches and cables are reorganized into actin bodies, which are stable actin filament–containing structures. Astonishingly, MTs are also stabilized and rearranged into a novel antiparallel bundle associated with the spindle pole body, named Q-MT bundle. We have identified proteins involved in this process and propose a molecular model for Q-MT bundle formation. Finally and importantly, we reveal that Q-MT bundle elongation is involved in polarity reestablishment upon quiescence exit and thereby the efficient return to the proliferative state. Our work demonstrates that quiescent S. pombe cells assemble specific cytoskeleton structures that improve the swiftness of the transition back to proliferation.

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Cosegregation of asymmetric features during cell division

Open Biology ◽

10.1098/rsob.210116 ◽

2021 ◽

Vol 11 (8) ◽

pp. 210116

Author(s):

Silje Anda ◽

Erik Boye ◽

Kay Oliver Schink ◽

Beata Grallert

Keyword(s):

Cell Division ◽

Schizosaccharomyces Pombe ◽

Spindle Pole Body ◽

Spindle Pole ◽

Unicellular Eukaryote ◽

Unicellular Eukaryotes ◽

Pole Body ◽

Cellular Asymmetry ◽

Multicellular Organisms ◽

Chromosome I

Cellular asymmetry plays a major role in the ageing and evolution of multicellular organisms. However, it remains unknown how the cell distinguishes ‘old’ from ‘new’ and whether asymmetry is an attribute of highly specialized cells or a feature inherent in all cells. Here, we investigate the segregation of three asymmetric features: old and new DNA, the spindle pole body (SPB, the centrosome analogue) and the old and new cell ends, using a simple unicellular eukaryote, Schizosaccharomyces pombe . To our knowledge, this is the first study exploring three asymmetric features in the same cells. We show that of the three chromosomes of S. pombe , chromosome I containing the new parental strand, preferentially segregated to the cells inheriting the old cell end. Furthermore, the new SPB also preferentially segregated to the cells inheriting the old end. Our results suggest that the ability to distinguish ‘old’ from ‘new’ and to segregate DNA asymmetrically are inherent features even in simple unicellular eukaryotes.

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The use of cell division cycle mutants to investigate the control of microtubule distribution in the fission yeast Schizosaccharomyces pombe

Journal of Cell Science ◽

10.1242/jcs.89.3.343 ◽

1988 ◽

Vol 89 (3) ◽

pp. 343-357 ◽

Cited By ~ 9

Author(s):

I.M. Hagan ◽

J.S. Hyams

Keyword(s):

Cell Division ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Spindle Pole Body ◽

Spindle Pole ◽

Cell Division Cycle ◽

Microtubule Organization ◽

Cytoplasmic Face ◽

Cytoplasmic Microtubules ◽

Positional Control

We have characterized the changes in microtubule organization that occur through the cell division cycle of the fission yeast Schizosaccharomyces pombe by indirect immunofluorescence microscopy. During interphase, groups of cytoplasmic microtubules, independent of the spindle pole body (SPB), form an array extending between the cell tips. These microtubules are involved in positioning the nucleus at the cell equator and in the establishment of cell polarity. At mitosis, the interphase array disappears and is replaced by an intranuclear spindle extending between the now duplicated SPBs. Elongation of the spindle sees the appearance of astral microtubules emanating from the cytoplasmic face of the SPBs. These persist until the end of anaphase whereupon the spindle microtubules depolymerize and two microtubule organizing centres (MTOCs) at the cell equator re-establish the interphase array. We have used the unique properties of various cell division cycle mutants to investigate further the function of these different microtubule arrays and their temporal and positional control.

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Spindle pole body components are reorganized during fission yeast meiosis

Molecular Biology of the Cell ◽

10.1091/mbc.e11-11-0951 ◽

2012 ◽

Vol 23 (10) ◽

pp. 1799-1811 ◽

Cited By ~ 24

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.

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Plo1 Kinase Recruitment to the Spindle Pole Body and Its Role in Cell Division inSchizosaccharomyces pombe

Molecular Biology of the Cell ◽

10.1091/mbc.10.8.2771 ◽

1999 ◽

Vol 10 (8) ◽

pp. 2771-2785 ◽

Cited By ~ 90

Author(s):

Daniel P. Mulvihill ◽

Janni Petersen ◽

Hiroyuki Ohkura ◽

David M. Glover ◽

Iain M. Hagan

Keyword(s):

Cell Division ◽

Fission Yeast ◽

Spindle Pole Body ◽

Spindle Pole ◽

Multiple Roles ◽

Anaphase Promoting Complex ◽

Pole Body ◽

Early Anaphase ◽

Anaphase B ◽

Mitotic Event

Polo kinases execute multiple roles during cell division. The fission yeast polo related kinase Plo1 is required to assemble the mitotic spindle, the prophase actin ring that predicts the site for cytokinesis and for septation after the completion of mitosis ( Ohkuraet al., 1995 ; Bahler et al., 1998 ). We show that Plo1 associates with the mitotic but not interphase spindle pole body (SPB). SPB association of Plo1 is the earliest fission yeast mitotic event recorded to date. SPB association is strong from mitotic commitment to early anaphase B, after which the Plo1 signal becomes very weak and finally disappears upon spindle breakdown. SPB association of Plo1 requires mitosis-promoting factor (MPF) activity, whereas its disassociation requires the activity of the anaphase-promoting complex. The stf1.1 mutation bypasses the usual requirement for the MPF activator Cdc25 ( Hudson et al., 1990 ). Significantly, Plo1 associates inappropriately with the interphase SPB of stf1.1 cells. These data are consistent with the emerging theme from many systems that polo kinases participate in the regulation of MPF to determine the timing of commitment to mitosis and may indicate that pole association is a key aspect of Plo1 function. Plo1 does not associate with the SPB when septation is inappropriately driven by deregulation of the Spg1 pathway and remains SPB associated if septation occurs in the presence of a spindle. Thus, neither Plo1 recruitment to nor its departure from the SPB are required for septation; however, overexpression ofplo1+activates the Spg1 pathway and causes transient Cdc7 recruitment to the SPB and multiple rounds of septation.

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Spindle assembly without spindle pole body insertion into the nuclear envelope in fission yeast meiosis

Chromosoma ◽

10.1007/s00412-019-00710-y ◽

2019 ◽

Vol 128 (3) ◽

pp. 267-277 ◽

Cited By ~ 3

Author(s):

Alberto Pineda-Santaella ◽

Alfonso Fernández-Álvarez

Keyword(s):

Nuclear Envelope ◽

Fission Yeast ◽

Spindle Pole Body ◽

Spindle Assembly ◽

Spindle Pole ◽

Pole Body ◽

Yeast Meiosis

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Calmodulin localizes to the spindle pole body of Schizosaccharomyces pombe and performs an essential function in chromosome segregation

Journal of Cell Science ◽

10.1242/jcs.110.15.1805 ◽

1997 ◽

Vol 110 (15) ◽

pp. 1805-1812 ◽

Cited By ~ 8

Author(s):

M.J. Moser ◽

M.R. Flory ◽

T.N. Davis

Keyword(s):

Cell Growth ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Chromosome Segregation ◽

Fluorescent Protein ◽

Budding Yeast ◽

Spindle Pole Body ◽

Spindle Pole ◽

Temperature Sensitive ◽

Pole Body

The essential calmodulin genes in both Saccharomyces cerevisiae and Schizosaccharomyces pombe were precisely replaced with genes encoding fusions between calmodulin and the green fluorescent protein (GFP). In living budding yeast the GFP-calmodulin fusion protein (GFP-Cmd1p) localized simultaneously to sites of cell growth and to the spindle pole body (SPB), the yeast analog of the centrosome. Having demonstrated proper localization of GFP-calmodulin in budding yeast, we examined the localization of a fusion between GFP and calmodulin (GFP-Camlp) in fission yeast, where calmodulin had not been localized by any method. We find GFP-Camlp also localizes both to sites of polarized cell growth and to the fission yeast SPB. The localization of calmodulin to the SPB by GFP fusion was confirmed by indirect immunofluorescence. Antiserum to S. pombe calmodulin labeled the ends of the mitotic spindle stained with anti-tubulin antiserum. This pattern was identical to that seen using antiserum to Sad1p, a known SPB component. We then characterized the defects in a temperature-sensitive S. pombe calmodulin mutant. Mutant cam1-E14 cells synchronized in S phase completed DNA synthesis, but lost viability during transit of mitosis. Severe defects in chromosome segregation, including hypercondensation, fragmentation, and unequal allocation of chromosomal material were observed. Immunofluorescence analysis of tubulin revealed a population of cells containing either broken or mislocalized mitotic spindles, which were never observed in wild-type cells. Taken together with the subcellular localization of calmodulin, the observed spindle and chromosome segregation defects suggest that calmodulin performs an essential role during mitosis at the fission yeast SPB.

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