scholarly journals Centrosome and spindle pole body dynamics: A review of the EMBO/EMBL Conference on Centrosomes and Spindle Pole Bodies, Heidelberg, September 13-17, 2002

2003 ◽  
Vol 54 (2) ◽  
pp. 148-154 ◽  
Author(s):  
Robert E. Palazzo
Keyword(s):  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Body Dynamics

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.

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.

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.

The fine structure of ascospore delimitation in the yeast Wickerhamia fluorescens

1973 ◽  
Vol 19 (11) ◽  
pp. 1389-1392 ◽  
Author(s):  
Lynn Rooney ◽  
Peter B. Moens
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fine Structure ◽  
Outer Membrane ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Spore Wall ◽  
Serial Sections ◽  
Spore Body ◽  
Pole Body ◽  
Spindle Pole Bodies

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.

scholarly journals Components of the yeast spindle and spindle pole body.

1990 ◽  
Vol 111 (5) ◽  
pp. 1913-1927 ◽  
Author(s):  
M P Rout ◽  
J V Kilmartin
Keyword(s):  
Spindle Pole Body ◽  
Spindle Pole ◽  
The Other ◽  
Yeast Cells ◽  
Immunofluorescent Staining ◽  
Cell Extracts ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Cytoplasmic Face ◽  
Spindle Microtubules

Yeast spindle pole bodies (SPBs) with attached nuclear microtubles were enriched approximately 600-fold from yeast cell extracts. 14 mAbs prepared against this enriched SPB fraction define at least three components of the SPB and spindle. Immunofluorescent staining of yeast cells showed that throughout the cell cycle two of the components (110 and 90 kD) were localized exclusively to the SPB region, and the other (80 kD) was localized both to the SPB region and to particulate dots in short spindles. Immunoelectron microscopy confirmed and extended most of these findings. Thus the 110-kD component was localized to a layer in the SPB just to the nuclear side of the plane of the inner nuclear membrane. The 90-kD component was localized in a layer across the cytoplasmic face of intact SPBs, and, in SPBs where nuclear microtubules were removed by extraction with DEAE-dextran, the 90-kD component was also found in an inner nuclear layer close to where spindle microtubules emerge. In intact SPBs with attached nuclear microtubules the anit-80-kD mAb labels microtubules, particularly those close to the SPB. These results begin to provide a preliminary molecular map of the SPB and should also enable the corresponding genes to be isolated.

scholarly journals MEIOSIS IN NEUROSPORA CRASSA. II. GENETIC AND CYTOLOGICAL CHARACTERIZATION OF THREE MEIOTIC MUTANTS

Genetics ◽  
1980 ◽  
Vol 96 (2) ◽  
pp. 379-398
Author(s):  
A M DeLange ◽  
A J F Griffiths
Keyword(s):  
Meiotic Recombination ◽  
Meiotic Division ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Primary Defect ◽  
Meiotic Mutants ◽  
Meiotic Chromosomes ◽  
Pole Body ◽  
Spindle Pole Bodies

ABSTRACT Three recessive meiotic mutants, asc(DL95), asc(DL243) and asc(DL879), were detected by the abortion of many of their ascospores and were analyzed using both cytological and genetic methods. Even though asc(DL95), asc(DL243) and the previously studied meiotic mutant, mei-1 (Smith 1975; Lu and Galeazzi 1978), complement one another in crosses, they apparently do not recombine (DeLange and Griffiths 1980). Thus, they may represent alleles of the same gene or comprise a gene cluster. Ascospore abortion in these mutants is caused by abnormal disjunction of meiotic chromosomes. In crosses homozygous for asc(DL95), asc(DL879) or mei-1, both pairing of homologs and meiotic recombination frequencies are reduced. In each case, this primary defect is followed by the formation of univalents at metaphase I and their irregular segregation. The mutant asc(DL243) has a defect in ascus formation, and later in disjunction during the second meiotic and post-meiotic divisions. The first-acting defect before or during karyogamy results in the abortion of most cells. Some cells manage to proceed past this block. During the second meiotic division, most chromosomes of the few resulting asci are attached to only one of the two spindle-pole bodies. Disjunction at the postmeiotic division is also highly irregular. This mutant appears to be defective in the attachment of one spindle-pole body to a set of chromosomes. The defect may involve either a centromere-associated product or a spindle-pole body.

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 Inactivation of Mitotic Kinase Triggers Translocation of MEN Components to Mother-Daughter Neck in Yeast

2003 ◽  
Vol 14 (11) ◽  
pp. 4734-4743 ◽  
Author(s):  
Hong Hwa Lim ◽  
Foong May Yeong ◽  
Uttam Surana
Keyword(s):  
Chromosome Segregation ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Mitotic Exit ◽  
Mitotic Kinase ◽  
Division Site ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Mitotic Exit Network ◽  
Mutant Cells

Chromosome segregation, mitotic exit, and cytokinesis are executed in this order during mitosis. Although a scheme coordinating sister chromatid separation and initiation of mitotic exit has been proposed, the mechanism that temporally links the onset of cytokinesis to mitotic exit is not known. Exit from mitosis is regulated by the mitotic exit network (MEN), which includes a GTPase (Tem1) and various kinases (Cdc15, Cdc5, Dbf2, and Dbf20). Here, we show that Dbf2 and Dbf20 functions are necessary for the execution of cytokinesis. Relocalization of these proteins from spindle pole bodies to mother daughter neck seems to be necessary for this role because cdc15-2 mutant cells, though capable of exiting mitosis at semipermissive temperature, are unable to localize Dbf2 (and Dbf20) to the “neck” and fail to undergo cytokinesis. These cells can assemble and constrict the actomyosin ring normally but are incapable of forming a septum, suggesting that MEN components are critical for the initiation of septum formation. Interestingly, the spindle pole body to neck translocation of Dbf2 and Dbf20 is triggered by the inactivation of mitotic kinase. The requirement of kinase inactivation for translocation of MEN components to the division site thus provides a mechanism that renders mitotic exit a prerequisite for cytokinesis.

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 Outer plaque assembly and spore encapsulation are defective during sporulation of adenylate cyclase-deficient mutants of Saccharomyces cerevisiae.

1985 ◽  
Vol 100 (6) ◽  
pp. 1854-1862 ◽  
Author(s):  
I Uno ◽  
K Matsumoto ◽  
A Hirata ◽  
T Ishikawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Adenylate Cyclase ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Sensitive Period ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
Diploid Cells

Sporulation in diploid cells homozygous for the cyr1-2 mutation of the yeast Saccharomyces cerevisiae was examined. This mutation causes a defect in adenylate cyclase and temperature-sensitive arrest in the G1 phase of the mitotic cell cycle. The cyr1-2/cyr1-2 diploid cells were able to initiate meiotic divisions, but produced predominantly two-spored asci at the restrictive temperature. Temperature-sensitive period for production of two-spored asci was approximately 12 h after the transfer of cells to the sporulation medium. The levels of cAMP increased during this period in the wild type and cyr1-2/cyr1-2 diploid cells incubated at the permissive temperature, but remained at an extremely low level in the cyr1-2/cyr1-2 diploid cells incubated at the restrictive temperature. Dyad analysis of the cyr1-2 strain indicated that meiotic products were randomly included into ascospores. Fluorescent microscopy of the cyr1-2/cyr1-2 diploid cells incubated at the restrictive temperature revealed that individual haploid nuclei were enclosed in each of the two spores after meiosis. About half of the cyr1-2/cyr1-2 diploid cells entered normal meiosis 1 producing two normal spindle pole bodies with inner and outer plaques, and the other half entered abnormal meiosis 1 producing one normal spindle pole body and one defective spindle pole body without out plaque. At meiosis II, some cells contained a pair of normal spindle pole bodies and other cells contained pairs of normal and abnormal spindle pole bodies.

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