scholarly journals Meiotic Spindle Pole Bodies Acquire the Ability to Assemble the Spore Plasma Membrane by Sequential Recruitment of Sporulation-specific Components in Fission Yeast

2008 ◽  
Vol 19 (6) ◽  
pp. 2476-2487 ◽  
Author(s):  
Yukiko Nakase ◽  
Michiko Nakamura-Kubo ◽  
Yanfang Ye ◽  
Aiko Hirata ◽  
Chikashi Shimoda ◽  
...  
Keyword(s):  
De Novo ◽  
Close Contact ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Deletion Mutants ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Cytoplasmic Side

The spindle pole body (SPB) of Schizosaccharomyces pombe is required for assembly of the forespore membrane (FSM) during meiosis. Before de novo biogenesis of the FSM, the meiotic SPB forms outer plaques, an event referred to as SPB modification. A constitutive SPB component, Spo15, plays an indispensable role in SPB modification and sporulation. Here, we analyzed two sporulation-specific genes, spo13+ and spo2+, which are not required for progression of meiotic nuclear divisions, but are essential for sporulation. Spo13 is a 16-kDa coiled-coil protein, and Spo2 is a 15-kDa nonconserved protein. Both Spo13 and Spo2 specifically associated with the meiotic SPB. The respective deletion mutants are viable, but defective in SPB modification and in the onset of FSM formation. Spo13 and Spo2 localized on the cytoplasmic side of the SPB in close contact with the nascent FSM. Localization of Spo13 to the SPB was dependent on Spo15 and Spo2; that of Spo2 depended only on Spo15, suggesting that their recruitment to the SPB is strictly controlled. Spo2 physically associated with both Spo15 and Spo13, but Spo13 and Spo15 did not interact directly. Taken together, these observations indicate that Spo2 is recruited to the SPB during meiosis and then assists in the localization of Spo13 to the outer surface of the SPB.

scholarly journals Vesicle Docking to the Spindle Pole Body Is Necessary to Recruit the Exocyst During Membrane Formation inSaccharomyces cerevisiae

2010 ◽  
Vol 21 (21) ◽  
pp. 3693-3707 ◽  
Author(s):  
Erin M. Mathieson ◽  
Yasuyuki Suda ◽  
Mark Nickas ◽  
Brian Snydsman ◽  
Trisha N. Davis ◽  
...  
Keyword(s):  
De Novo ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Resonance Energy ◽  
Initiation Site ◽  
Spindle Pole ◽  
Rab Gtpase ◽  
Membrane Formation ◽  
Vesicle Docking ◽  
Pole Body

During meiosis II in Saccharomyces cerevisiae, the cytoplasmic face of the spindle pole body, referred to as the meiosis II outer plaque (MOP), is modified in both composition and structure to become the initiation site for de novo formation of a membrane called the prospore membrane. The MOP serves as a docking complex for precursor vesicles that are targeted to its surface. Using fluorescence resonance energy transfer analysis, the orientation of coiled-coil proteins within the MOP has been determined. The N-termini of two proteins, Mpc54p and Spo21p, were oriented toward the outer surface of the structure. Mutations in the N-terminus of Mpc54p resulted in a unique phenotype: precursor vesicles loosely tethered to the MOP but did not contact its surface. Thus, these mpc54 mutants separate the steps of vesicle association and docking. Using these mpc54 mutants, we determined that recruitment of the Rab GTPase Sec4p, as well as the exocyst components Sec3p and Sec8p, to the precursor vesicles requires vesicle docking to the MOP. This suggests that the MOP promotes membrane formation both by localization of precursor vesicles to a particular site and by recruitment of a second tethering complex, the exocyst, that stimulates downstream events of fusion.

S. pombe sporulation-specific coiled-coil protein Spo15p is localized to the spindle pole body and essential for its modification

2000 ◽  
Vol 113 (3) ◽  
pp. 545-554 ◽  
Author(s):  
S. Ikemoto ◽  
T. Nakamura ◽  
M. Kubo ◽  
C. Shimoda
Keyword(s):  
Life Cycle ◽  
Fusion Gene ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Wild Type ◽  
Membrane Formation ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Meiotic Spindles

Spindle pole bodies in the fission yeast Schizosaccharomyces pombe are required during meiosis, not only for spindle formation but also for the assembly of forespore membranes. The spo15 mutant is defective in the formation of forespore membranes, which develop into spore envelopes. The spo15(+)gene encodes a protein with a predicted molecular mass of 223 kDa, containing potential coiled-coil regions. The spo15 gene disruptant was not lethal, but was defective in spore formation. Northern and western analyses indicated that spo15(+) was expressed not only in meiotic cells but also in vegetative cells. When the spo15-GFP fusion gene was expressed by the authentic spo15 promoter during vegetative growth and sporulation, the fusion protein colocalized with Sad1p, which is a component of spindle pole bodies. Meiotic divisions proceeded in spo15delta cells with kinetics similar to those in wild-type cells. In addition, the morphology of the mitotic and meiotic spindles and the nuclear segregation were normal in spo15delta. Intriguingly, transformation of spindle pole bodies from a punctate to a crescent form prior to forespore membrane formation was not observed in spo15delta cells. We conclude that Spo15p is associated with spindle pole bodies throughout the life cycle and plays an indispensable role in the initiation of spore membrane formation.

The spindle pole body cycle, meiosis, and basidial cytology of the smut fungus Microbotryum violaceum

1991 ◽  
Vol 69 (8) ◽  
pp. 1795-1803 ◽  
Author(s):  
Mary L. Berbee ◽  
Robert Bauer ◽  
F. Oberwinkler
Keyword(s):  
Spindle Pole Body ◽  
Freeze Substitution ◽  
Ustilago Maydis ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Smut Fungus ◽  
Microbotryum Violaceum ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Middle Piece

Freeze-substituted basidia of the smut fungus Microbotryum violaceum (Ustilaginales, Basidiomycotina) were examined electron microscopically with particular attention to the meiotic spindle pole body cycle and cytoplasmic characters of phylogenetic significance. Prophase basidia contained a subapical cluster of vesicles and tubules. During prophase, the spindle pole body consisted of two globular elements connected by a middle piece. The spindle pole body had an electron-opaque layer near the nucleus, and each globular element was bisected by an electron-opaque disk. The meiosis I spindle extended between two monoglobular, disc-containing spindle pole bodies. During interphase I and II, septa lacking pores divided the basidium between daughter nuclei. In interphase I, a putative new spindle pole body appeared between the nuclear envelope and the monoglobular spindle pole body residual from the first division. In meiosis II, a spindle was again established between two monoglobular spindle pole bodies, each of which again contained an electron-opaque disc. The cytoplasmic characters of M. violaceum are compared with those of Ustilago maydis and Sphacelotheca polygoni-serrulati. Key words: Microbotryum violaceum, basidiomycete, Ustilaginales, spindle pole body, freeze-substitution, ultrastructure.

scholarly journals Ady4p and Spo74p Are Components of the Meiotic Spindle Pole Body That Promote Growth of the Prospore Membrane in Saccharomyces cerevisiae

2003 ◽  
Vol 2 (3) ◽  
pp. 431-445 ◽  
Author(s):  
Mark E. Nickas ◽  
Cindi Schwartz ◽  
Aaron M. Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Membrane Formation ◽  
Auxiliary Component ◽  
Pole Body ◽  
Prospore Membrane ◽  
Organizing Center

ABSTRACT Spore formation in Saccharomyces cerevisiae occurs via the de novo synthesis of the prospore membrane during the second meiotic division. Prospore membrane formation is triggered by assembly of a membrane-organizing center, the meiotic outer plaque (MOP), on the cytoplasmic face of the spindle pole body (SPB) during meiosis. We report here the identification of two new components of the MOP, Ady4p and Spo74p. Ady4p and Spo74p interact with known proteins of the MOP and are localized to the outer plaque of the SPB during meiosis II. MOP assembly and prospore membrane formation are abolished in spo74Δ/spo74Δ cells and occur aberrantly in ady4Δ/ady4Δ cells. Spo74p and the MOP component Mpc70p are mutually dependent for recruitment to SPBs during meiosis. In contrast, both Ady4p and Spo74p are present at SPBs, albeit at reduced levels, in cells that lack the MOP component Mpc54p. Our findings suggest a model for the assembled MOP in which Mpc54p, Mpc70p, and Spo74p make up a core structural unit of the scaffold that initiates synthesis of the prospore membrane, and Ady4p is an auxiliary component that stabilizes the plaque.

Ady3p Links Spindle Pole Body Function to Spore Wall Synthesis in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1439-1450
Author(s):  
Mark E Nickas ◽  
Aaron M Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Spindle Pole Body ◽  
Leading Edge ◽  
Spindle Pole ◽  
Spore Wall ◽  
Pole Body ◽  
Prospore Membrane ◽  
Sporulation Efficiency ◽  
Spore Walls

Abstract Spore formation in Saccharomyces cerevisiae requires the de novo synthesis of prospore membranes and spore walls. Ady3p has been identified as an interaction partner for Mpc70p/Spo21p, a meiosis-specific component of the outer plaque of the spindle pole body (SPB) that is required for prospore membrane formation, and for Don1p, which forms a ring-like structure at the leading edge of the prospore membrane during meiosis II. ADY3 expression has been shown to be induced in midsporulation. We report here that Ady3p interacts with additional components of the outer and central plaques of the SPB in the two-hybrid assay. Cells that lack ADY3 display a decrease in sporulation efficiency, and most ady3Δ/ady3Δ asci that do form contain fewer than four spores. The sporulation defect in ady3Δ/ady3Δ cells is due to a failure to synthesize spore wall polymers. Ady3p forms ring-like structures around meiosis II spindles that colocalize with those formed by Don1p, and Don1p rings are absent during meiosis II in ady3Δ/ady3Δ cells. In mpc70Δ/mpc70Δ cells, Ady3p remains associated with SPBs during meiosis II. Our results suggest that Ady3p mediates assembly of the Don1p-containing structure at the leading edge of the prospore membrane via interaction with components of the SPB and that this structure is involved in spore wall formation.

Ultrastructure of meiosis and the spindle pole body cycle in freeze-substituted basidia of the smut fungi Ustilago maydis and Ustilago avenae

1992 ◽  
Vol 70 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Kerry O'Donnell
Keyword(s):  
Electron Microscopy ◽  
Spindle Pole Body ◽  
Ustilago Maydis ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Smut Fungi ◽  
Late Prophase ◽  
Prophase I ◽  
Pole Body ◽  
Middle Piece

Meiosis in the smut fungi Ustilago maydis and Ustilago avenae (Basidiomycota, Ustilaginales) was studied by electron microscopy of serial-sectioned freeze substituted basidia. At prophase I, a spindle pole body composed of two globular elements connected by a middle piece was attached to the extranuclear surface of each nucleus. Astral and spindle microtubules were initiated at each globular element at late prophase I to prometaphase I. During spindle initiation, the middle piece disappeared and interdigitating half-spindles entered the nucleoplasm, which was surrounded by discontinuous nuclear envelope together with perinuclear endoplasmic reticulum. Kinetochore pairs at metaphase I were analyzed to obtain a karyotype for each species. The meiotic spindle pole body replicational cycle is described. Key words: electron microscopy, freeze-substitution, meiosis, Ustilago, spindle pole body.

scholarly journals The Fission Yeast Homolog of the Human Transcription Factor EAP30 Blocks Meiotic Spindle Pole Body Amplification

2005 ◽  
Vol 9 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Ye Jin ◽  
Joel J. Mancuso ◽  
Satoru Uzawa ◽  
Daniela Cronembold ◽  
W. Zacheus Cande
Keyword(s):  
Transcription Factor ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Pole Body ◽  
Yeast Homolog ◽  
Human Transcription Factor

scholarly journals Spc98p Directs the Yeast γ-Tubulin Complex into the Nucleus and Is Subject to Cell Cycle-dependent Phosphorylation on the Nuclear Side of the Spindle Pole Body

1998 ◽  
Vol 9 (4) ◽  
pp. 775-793 ◽  
Author(s):  
Gislene Pereira ◽  
Michael Knop ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Mitotic Checkpoint ◽  
Spindle Pole ◽  
Nuclear Localization Sequence ◽  
Checkpoint Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body ◽  
Cycle Dependent ◽  
Cytoplasmic Side

In the yeast Saccharomyces cerevisiae, microtubules are organized by the spindle pole body (SPB), which is embedded in the nuclear envelope. Microtubule organization requires the γ-tubulin complex containing the γ-tubulin Tub4p, Spc98p, and Spc97p. The Tub4p complex is associated with cytoplasmic and nuclear substructures of the SPB, which organize the cytoplasmic and nuclear microtubules. Here we present evidence that the Tub4p complex assembles in the cytoplasm and then either binds to the cytoplasmic side of the SPB or is imported into the nucleus followed by binding to the nuclear side of the SPB. Nuclear import of the Tub4p complex is mediated by the essential nuclear localization sequence of Spc98p. Our studies also indicate that Spc98p in the Tub4p complex is phosphorylated at the nuclear, but not at the cytoplasmic, side of the SPB. This phosphorylation is cell cycle dependent and occurs after SPB duplication and nucleation of microtubules by the new SPB and therefore may have a role in mitotic spindle function. In addition, activation of the mitotic checkpoint stimulates Spc98p phosphorylation. The kinase Mps1p, which functions in SPB duplication and mitotic checkpoint control, seems to be involved in Spc98p phosphorylation. Our results also suggest that the nuclear and cytoplasmic Tub4p complexes are regulated differently.

scholarly journals Conservative Duplication of Spindle Poles during Meiosis in Saccharomyces cerevisiae

2001 ◽  
Vol 183 (7) ◽  
pp. 2372-2375 ◽  
Author(s):  
Andreas Wesp ◽  
Susanne Prinz ◽  
Gerald R. Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Spore Formation ◽  
Wild Type ◽  
Body Distribution ◽  
Spindle Poles ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Type Strains

ABSTRACT During sporulation in diploid Saccharomyces cerevisiae, spindle pole bodies acquire the so-called meiotic plaque, a prerequisite for spore formation. Mpc70p is a component of the meiotic plaque and is thus essential for spore formation. We show here that MPC70/mpc70 heterozygous strains most often produce two spores instead of four and that these spores are always nonsisters. In wild-type strains, Mpc70p localizes to all four spindle pole bodies, whereas in MPC70/mpc70 strains Mpc70p localizes to only two of the four spindle pole bodies, and these are always nonsisters. Our data can be explained by conservative spindle pole body distribution in which the two newly synthesized meiosis II spindle pole bodies of MPC70/mpc70 strains lack Mpc70p.

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