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

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.

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

Canadian Journal of Botany ◽

10.1139/b92-081 ◽

1992 ◽

Vol 70 (3) ◽

pp. 629-638 ◽

Cited By ~ 8

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.

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Spindle pole body fusion in the smut fungus Tilletia foetida

Canadian Journal of Botany ◽

10.1139/b86-166 ◽

1986 ◽

Vol 64 (6) ◽

pp. 1221-1223 ◽

Cited By ~ 4

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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An electron microscopic study of meiosis and the spindle pole body cycle in the smut fungus Sphacelotheca polygoni-serrulati

Canadian Journal of Botany ◽

10.1139/b91-035 ◽

1991 ◽

Vol 69 (2) ◽

pp. 245-255 ◽

Cited By ~ 15

Author(s):

Robert Bauer ◽

Mary L. Berbee ◽

Franz Oberwinkler

Keyword(s):

Microscopic Study ◽

Electron Microscopic Study ◽

Spindle Pole Body ◽

Spindle Pole ◽

Meiotic Spindle ◽

Smut Fungus ◽

Electron Microscopic ◽

Pole Body ◽

Intact Surface ◽

Metaphase I

An electron microscopic study was made of meiosis and the meiotic spindle pole body (SPB) cycle in germinating teliospores of the smut fungus Sphacelotheca polygoni-serrulati. SPB development in prophase I and duplication in interphase I were studied in detail. During prophase, the globular elements of the biglobular SPB enlarged, became oblate in form, developed internal layering, and became associated with astral microtubules. The middle piece decreased in size and finally disappeared. Prior to metaphase I, the two oblate elements moved apart along the intact surface of the nuclear envelope, and the nuclear membrane bulged into the space between the two SPBs. Metaphase I – early telophase I and metaphase II – early telophase II SPBs were intranuclear, oblate spheroidal in shape, and traversed by an electron-dense disc. In interphase I, an electron-dense bar appeared in association with the nuclear side of the original SPB. The bar initially overlapped one edge of the electron-dense disc and later appeared at the side of the disc. The bar became one of the metaphase II SPBs. Similarities and differences between meiosis and SPBs in Sphacelotheca polygoni-serrulati, Ustilago maydis, Ustilago esculenta, Tilletia foetida, and other heterobasidiomycetes are discussed. Key words: heterobasidiomycetes, Ustilaginales, Sphacelotheca, meiosis, spindle pole body, ultrastructure.

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

Molecular Biology of the Cell ◽

10.1091/mbc.e08-02-0118 ◽

2008 ◽

Vol 19 (6) ◽

pp. 2476-2487 ◽

Cited By ~ 23

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.

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Faculty Opinions recommendation of Fission yeast Myo51 is a meiotic spindle pole body component with discrete roles during cell fusion and spore formation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.2137023.1737135 ◽

2010 ◽

Author(s):

Christopher McInerny

Keyword(s):

Fission Yeast ◽

Cell Fusion ◽

Spindle Pole Body ◽

Spindle Pole ◽

Spore Formation ◽

Meiotic Spindle ◽

Pole Body ◽

Body Component

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

Developmental Cell ◽

10.1016/j.devcel.2005.04.016 ◽

2005 ◽

Vol 9 (1) ◽

pp. 63-73 ◽

Cited By ~ 20

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

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Conservative Duplication of Spindle Poles during Meiosis in Saccharomyces cerevisiae

Journal of Bacteriology ◽

10.1128/jb.183.7.2372-2375.2001 ◽

2001 ◽

Vol 183 (7) ◽

pp. 2372-2375 ◽

Cited By ~ 10

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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Microtubules in the fungal pathogen Ustilago maydis are highly dynamic and determine cell polarity

Journal of Cell Science ◽

10.1242/jcs.114.3.609 ◽

2001 ◽

Vol 114 (3) ◽

pp. 609-622 ◽

Cited By ~ 6

Author(s):

G. Steinberg ◽

R. Wedlich-Soldner ◽

M. Brill ◽

I. Schulz

Keyword(s):

Cell Polarity ◽

Fungal Pathogens ◽

Spindle Pole Body ◽

Ustilago Maydis ◽

Spindle Pole ◽

Microtubule Organization ◽

Growth Region ◽

Alpha Tubulin ◽

Pole Body

Many fungal pathogens undergo a yeast-hyphal transition during their pathogenic development that requires rearrangement of the cytoskeleton, followed by directed membrane traffic towards the growth region. The role of microtubules and their dynamic behavior during this process is not well understood. Here we set out to elucidate the organization, cellular role and in vivo dynamics of microtubules in the dimorphic phytopathogen Ustilago maydis. Hyphae and unbudded yeast-like cells of U. maydis contain bundles of spindle pole body-independent microtubules. At the onset of bud formation two spherical tubulin structures focus microtubules towards the growth region, suggesting that they support polar growth in G(2), while spindle pole body-nucleated astral microtubules participate in nuclear migration in M and early G(1). Conditional mutants of an essential alpha-tubulin gene from U. maydis, tub1, confirmed a role for interphase microtubules in determination of cell polarity and growth. Observation of GFP-Tub1 fusion protein revealed that spindle pole body-independent and astral microtubules are dynamic, with elongation and shrinkage rates comparable to those found in vertebrate systems. In addition, very fast depolymerization was measured within microtubule bundles. Unexpectedly, interphase microtubules underwent bending and rapid translocations within the cell, suggesting that unknown motor activities participate in microtubule organization in U. maydis. Movies available on-line: http://www.biologists.com/JCS/movies/jcs1792.html

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

Journal of Cell Science ◽

10.1242/jcs.113.3.545 ◽

2000 ◽

Vol 113 (3) ◽

pp. 545-554 ◽

Cited By ~ 8

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.

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