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

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.

2003 ◽  
Vol 2 (3) ◽  
pp. 431-445 ◽  
Author(s):  
Mark E. Nickas ◽  
Cindi Schwartz ◽  
Aaron M. Neiman

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.


1973 ◽  
Vol 19 (11) ◽  
pp. 1389-1392 ◽  
Author(s):  
Lynn Rooney ◽  
Peter B. Moens

Photographic records of complete serial sections of asci in different stages of sporulation show that one of the four nuclear lobes produced during meiosis in the ascus of the yeast Wickerhamia fluorescens has a complex spindle-pole body, which is the site from where the presumptive ascospore wall, or prospore wall, develops and eventually surrounds the ascospore nucleus and associated cytoplasm. The three remaining nuclei develop spindle-pole bodies and prospore walls to lesser and varying degrees. With few exceptions, all three degenerate. The outer membrane of the prospore wall forms a fold, or rim, on the outside of the spore. Thickening of the spore wall takes place first in the asymmetric ring, then around the spore body, and finally at the site where the nucleus is associated with the wall. It is shown that ascospore delimitation in W. fluorescens and Saccharomyces cerevisiae are similar to each other, and that it differs from the type observed in a number of Euascomycetes.


2021 ◽  
Vol 7 (1) ◽  
pp. 53
Author(s):  
Matthew Durant ◽  
Joseph M. Roesner ◽  
Xheni Mucelli ◽  
Christian J. Slubowski ◽  
Erin Klee ◽  
...  

During sporulation in the budding yeast Saccharomyces cerevisiae, proper development of the prospore membrane is necessary for the formation of viable spores. The prospore membrane will eventually become the plasma membrane of the newly formed haploid spore and also serves as the template for the deposition of the spore wall. The prospore membrane is generated de novo during meiosis II and the growing edge of the prospore membrane is associated with the Leading Edge Protein (LEP) complex. We find that the Smk1 MAP kinase, along with its activator Ssp2, transiently localizes with the LEP during late meiosis II. SSP2 is required for the leading edge localization of Smk1; this localization is independent of the activation state of Smk1. Like other LEP components, the localization of Smk1 at the leading edge also depends on Ady3. Although prospore membrane development begins normally in smk1 and ssp2 mutants, late prospore membrane formation is disrupted, with the formation of ectopic membrane compartments. Thus, MAP kinase signaling plays an important role in the formation of the prospore membrane.


1980 ◽  
Vol 46 (1) ◽  
pp. 341-352
Author(s):  
R.A. Quinlan ◽  
C.I. Pogson ◽  
K. Gull

Methyl benzimidazol-2-yl-carbamate (MBC), at a concentration of 100 microM, has a pronounced effect on the growth of Saccharomyces cerevisiae, resulting in the accumulation of cells as large doublets. We have determined a specific execution point for the effect of MBC on the yeast cell cycle, and have shown that this execution point is between the cycle events of spindle pole body duplication and spindle pole body separation. An ultrastructural examination of the MBC-treated cells revealed the absence of cytoplasmic and spindle microtubules. MBC treatment also produced an altered spindle pole body morphology, causing the disappearance of the outer component. Nuclear size was also markedly increased in the MBC-induced doublet cells, although the septa were completely absent from these doublet cells. It is proposed that MBC inhibits microtubule polymerization, rather than causing the depolymerization of stable microtubules.


1986 ◽  
Vol 6 (6) ◽  
pp. 2213-2222 ◽  
Author(s):  
B Futcher ◽  
J Carbon

Plasmids carrying a Saccharomyces cerevisiae centromere have a copy number of one or two, whereas other yeast plasmids have high copy numbers. The number of CEN plasmids per yeast cell was made artificially high by transforming cells simultaneously with several different CEN plasmids carrying different, independently selectable markers. Some host cells carried five different CEN plasmids and an average total of 13 extra copies of CEN3. Several effects were noted. The copy number of each plasmid was unexpectedly high. The plasmids were mutually unstable. Cultures contained many dead cells. The viable host cells grew more slowly than control cells, even in nonselective medium. There was a pause in the cell cycle at or just before mitosis. We conclude that an excess of centromeres is toxic and that the copy number of centromere plasmids is low partly because of selection against cells carrying multiple centromere plasmids. The toxicity may be caused by competition between the centromeres for some factor present in limiting quantities, e.g., centromere-binding proteins, microtubules, or space on the spindle pole body.


2017 ◽  
Vol 28 (26) ◽  
pp. 3881-3895 ◽  
Author(s):  
Tsuyoshi S. Nakamura ◽  
Yumi Numajiri ◽  
Yuuya Okumura ◽  
Junji Hidaka ◽  
Takayuki Tanaka ◽  
...  

During the developmental process of sporulation in Saccharomyces cerevisiae, membrane structures called prospore membranes are formed de novo, expand, extend, acquire a round shape, and finally become plasma membranes of the spores. GIP1 encodes a regulatory/targeting subunit of protein phosphatase type 1 that is required for sporulation. Gip1 recruits the catalytic subunit Glc7 to septin structures that form along the prospore membrane; however, the molecular basis of its localization and function is not fully understood. Here we show that Gip1 changes its localization dynamically and is required for prospore membrane extension. Gip1 first associates with the spindle pole body as the prospore membrane forms, moves onto the prospore membrane and then to the septins as the membrane extends, distributes around the prospore membrane after closure, and finally translocates into the nucleus in the maturing spore. Deletion and mutation analyses reveal distinct sequences in Gip1 that are required for different localizations and for association with Glc7. Binding to Glc7 is also required for proper localization. Strikingly, localization to the prospore membrane, but not association with septins, is important for Gip1 function. Further, our genetic analysis suggests that a Gip1–Glc7 phosphatase complex regulates prospore membrane extension in parallel to the previously reported Vps13, Spo71, Spo73 pathway.


2010 ◽  
Vol 30 (8) ◽  
pp. 2057-2074 ◽  
Author(s):  
Masayuki Onishi ◽  
Takako Koga ◽  
Aiko Hirata ◽  
Taro Nakamura ◽  
Haruhiko Asakawa ◽  
...  

ABSTRACT During yeast sporulation, a forespore membrane (FSM) initiates at each spindle-pole body and extends to form the spore envelope. We used Schizosaccharomyces pombe to investigate the role of septins during this process. During the prior conjugation of haploid cells, the four vegetatively expressed septins (Spn1, Spn2, Spn3, and Spn4) coassemble at the fusion site and are necessary for its normal morphogenesis. Sporulation involves a different set of four septins (Spn2, Spn5, Spn6, and the atypical Spn7) that does not include the core subunits of the vegetative septin complex. The four sporulation septins form a complex in vitro and colocalize interdependently to a ring-shaped structure along each FSM, and septin mutations result in disoriented FSM extension. The septins and the leading-edge proteins appear to function in parallel to orient FSM extension. Spn2 and Spn7 bind to phosphatidylinositol 4-phosphate [PtdIns(4)P] in vitro, and PtdIns(4)P is enriched in the FSMs, suggesting that septins bind to the FSMs via this lipid. Cells expressing a mutant Spn2 protein unable to bind PtdIns(4)P still form extended septin structures, but these structures fail to associate with the FSMs, which are frequently disoriented. Thus, septins appear to form a scaffold that helps to guide the oriented extension of the FSM.


2010 ◽  
Vol 21 (21) ◽  
pp. 3693-3707 ◽  
Author(s):  
Erin M. Mathieson ◽  
Yasuyuki Suda ◽  
Mark Nickas ◽  
Brian Snydsman ◽  
Trisha N. Davis ◽  
...  

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.


2001 ◽  
Vol 183 (7) ◽  
pp. 2372-2375 ◽  
Author(s):  
Andreas Wesp ◽  
Susanne Prinz ◽  
Gerald R. Fink

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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