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.

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.

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.

scholarly journals ADY1, A Novel Gene Required for Prospore Membrane Formation at Selected Spindle Poles inSaccharomyces cerevisiae

2001 ◽  
Vol 12 (9) ◽  
pp. 2646-2659 ◽  
Author(s):  
Changchun Deng ◽  
William S. Saunders
Keyword(s):  
Meiotic Chromosome ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Membrane Formation ◽  
Spindle Poles ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Prospore Membrane ◽  
A Cell ◽  
Body Component

ADY1 is identified in a genetic screen for genes on chromosome VIII of Saccharomyces cerevisiae that are required for sporulation. ADY1 is not required for meiotic recombination or meiotic chromosome segregation, but it is required for the formation of four spores inside an ascus. In the absence of ADY1, prospore formation is restricted to mainly one or two spindle poles per cell. Moreover, the two spores in the dyads of the ady1 mutant are predominantly nonsisters, suggesting that the proficiency to form prospores is not randomly distributed to the four spindle poles in theady1 mutant. Interestingly, the meiosis-specific spindle pole body component Mpc54p, which is known to be required for prospore membrane formation, is localized predominantly to only one or two spindle poles per cell in the ady1 mutant. A partially functional Myc-Pfs1p is localized to the nucleus of mononucleate meiotic cells but not to the spindle pole body or prospore membrane. These results suggest that Pfs1p is specifically required for prospore formation at selected spindle poles, most likely by ensuring the functionality of all four spindle pole bodies of a cell during meiosis II.

scholarly journals Mutational Analysis Reveals a Role for the C Terminus of the Proteasome Subunit Rpt4p in Spindle Pole Body Duplication inSaccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 705-720 ◽  
Author(s):  
Heather B McDonald ◽  
Astrid Hoes Helfant ◽  
Erin M Mahony ◽  
Shaun K Khosla ◽  
Loretta Goetsch
Keyword(s):  
Cell Cycle ◽  
Mutational Analysis ◽  
Genetic Interaction ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Terminal Region ◽  
Wild Type ◽  
Pole Body ◽  
C Terminus

AbstractThe ubiquitin/proteasome pathway plays a key role in regulating cell cycle progression. Previously, we reported that a conditional mutation in the Saccharomyces cerevisiae gene RPT4/PCS1, which encodes one of six ATPases in the proteasome 19S cap complex/regulatory particle (RP), causes failure of spindle pole body (SPB) duplication. To improve our understanding of Rpt4p, we created 58 new mutations, 53 of which convert clustered, charged residues to alanine. Virtually all mutations that affect the N-terminal region, which contains a putative nuclear localization signal and coiled-coil motif, result in a wild-type phenotype. Nine mutations that affect the central ATPase domain and the C-terminal region confer recessive lethality. The two conditional mutations identified, rpt4-145 and rpt4-150, affect the C terminus. After shift to high temperature, these mutations generally cause cells to progress slowly through the first cell cycle and to arrest in the second cycle with large buds, a G2 content of DNA, and monopolar spindles, although this phenotype can vary depending on the medium. Additionally, we describe a genetic interaction between RPT4 and the naturally polymorphic gene SSD1, which in wild-type form modifies the rpt4-145 phenotype such that cells arrest in G2 of the first cycle with complete bipolar spindles.

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 Mutant Membrane Protein of the Budding Yeast Spindle Pole Body Is Targeted to the Endoplasmic Reticulum Degradation Pathway

Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 567-578 ◽  
Author(s):  
Susan McBratney ◽  
Mark Winey
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole Body ◽  
Degradation Pathway ◽  
Spindle Pole ◽  
Wild Type ◽  
Er Quality Control ◽  
Pole Body ◽  
Cytoplasmic Face ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Conjugation

Abstract Mutation of either the yeast MPS2 or the NDC1 gene leads to identical spindle pole body (SPB) duplication defects: The newly formed SPB is improperly inserted into the nuclear envelope (NE), preventing the cell from forming a bipolar mitotic spindle. We have previously shown that both MPS2 and NDC1 encode integral membrane proteins localized at the SPB. Here we show that CUE1, previously known to have a role in coupling ubiquitin conjugation to ER degradation, is an unusual dosage suppressor of mutations in MPS2 and NDC1. Cue1p has been shown to recruit the soluble ubiquitin-conjugating enzyme, Ubc7p, to the cytoplasmic face of the ER membrane where it can ubiquitinate its substrates and target them for degradation by the proteasome. Both mps2-1 and ndc1-1 are also suppressed by disruption of UBC7 or its partner, UBC6. The Mps2-1p mutant protein level is markedly reduced compared to wild-type Mps2p, and deletion of CUE1 restores the level of Mps2-1p to nearly wild-type levels. Our data indicate that Mps2p may be targeted for degradation by the ER quality control pathway.

scholarly journals Structural Mutants of the Spindle Pole Body Cause Distinct Alteration of Cytoplasmic Microtubules and Nuclear Dynamics in Multinucleated Hyphae

2010 ◽  
Vol 21 (5) ◽  
pp. 753-766 ◽  
Author(s):  
Claudia Lang ◽  
Sandrine Grava ◽  
Mark Finlayson ◽  
Rhonda Trimble ◽  
Peter Philippsen ◽  
...  
Keyword(s):  
Spindle Pole Body ◽  
Spindle Pole ◽  
Wild Type ◽  
Nuclear Dynamics ◽  
Pole Body ◽  
Nucleation Sites ◽  
Bridge Structures ◽  
Cytoplasmic Microtubules ◽  
Tangential Directions

In the multinucleate fungus Ashbya gossypii, cytoplasmic microtubules (cMTs) emerge from the spindle pole body outer plaque (OP) in perpendicular and tangential directions. To elucidate the role of cMTs in forward/backward movements (oscillations) and bypassing of nuclei, we constructed mutants potentially affecting cMT nucleation or stability. Hyphae lacking the OP components AgSpc72, AgNud1, AgCnm67, or the microtubule-stabilizing factor AgStu2 grew like wild- type but showed substantial alterations in the number, length, and/or nucleation sites of cMTs. These mutants differently influenced nuclear oscillation and bypassing. In Agspc72Δ, only long cMTs were observed, which emanate tangentially from reduced OPs; nuclei mainly moved with the cytoplasmic stream but some performed rapid bypassing. Agnud1Δ and Agcnm67Δ lack OPs; short and long cMTs emerged from the spindle pole body bridge/half-bridge structures, explaining nuclear oscillation and bypassing in these mutants. In Agstu2Δ only very short cMTs emanated from structurally intact OPs; all nuclei moved with the cytoplasmic stream. Therefore, long tangential cMTs promote nuclear bypassing and short cMTs are important for nuclear oscillation. Our electron microscopy ultrastructural analysis also indicated that assembly of the OP occurs in a stepwise manner, starting with AgCnm67, followed by AgNud1 and lastly AgSpc72.

scholarly journals Nuf2, a spindle pole body-associated protein required for nuclear division in yeast.

1994 ◽  
Vol 125 (4) ◽  
pp. 853-866 ◽  
Author(s):  
M A Osborne ◽  
G Schlenstedt ◽  
T Jinks ◽  
P A Silver
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Temperature Shift ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Yeast Saccharomyces Cerevisiae ◽  
Culture Cells ◽  
Pole Body ◽  
Associated Proteins

The NUF2 gene of the yeast Saccharomyces cerevisiae encodes an essential 53-kd protein with a high content of potential coiled-coil structure similar to myosin. Nuf2 is associated with the spindle pole body (SPB) as determined by coimmunofluorescence with known SPB proteins. Nuf2 appears to be localized to the intranuclear region and is a candidate for a protein involved in SPB separation. The nuclear association of Nuf2 can be disrupted, in part, by 1 M salt but not by the detergent Triton X-100. All Nuf2 can be removed from nuclei by 8 M urea extraction. In this regard, Nuf2 is similar to other SPB-associated proteins including Nufl/SPC110, also a coiled-coil protein. Temperature-sensitive alleles of NUF2 were generated within the coiled-coil region of Nuf2 and such NUF2 mutant cells rapidly arrest after temperature shift with a single undivided or partially divided nucleus in the bud neck, a shortened mitotic spindle and their DNA fully replicated. In sum, Nuf2 is a protein associated with the SPB that is critical for nuclear division. Anti-Nuf2 antibodies also recognize a mammalian 73-kd protein and display centrosome staining of mammalian tissue culture cells suggesting the presence of a protein with similar function.

Spindle pole body fusion in the smut fungus Tilletia foetida

1986 ◽  
Vol 64 (6) ◽  
pp. 1221-1223 ◽  
Author(s):  
Blair J. Goates ◽  
James A. Hoffmann
Keyword(s):  
Nuclear Fusion ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Smut Fungus ◽  
Narrow Region ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Tilletia Foetida

Fusion of double-structured, interphase spindle pole bodies (SPBs) occurred before nuclear fusion in heterokaryotic secondary sporidia. The SPBs of two separate nuclei were juxtaposed with their long axes perpendicular to each other. Also, SPBs were observed oriented with their long axes parallel and fused to each other at both ends. Fusion apparently continued toward the midportion of the SPBs. Nuclei were observed joined together in a narrow region. These nuclei appeared to share a single SPB that was located opposite to a protuberance on both nuclei. Following fusion, the SPB apparently returned to an interphase structure.

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