scholarly journals Spindle Pole Body Duplication in Fission Yeast Occurs at the G1/S Boundary but Maturation Is Blocked until Exit from S by an Event Downstream of Cdc10+

2004 ◽  
Vol 15 (12) ◽  
pp. 5219-5230 ◽  
Author(s):  
Satoru Uzawa ◽  
Fei Li ◽  
Ye Jin ◽  
Kent L. McDonald ◽  
Michael B. Braunfeld ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Specific Inhibitor ◽  
Spindle Pole ◽  
Feedback Mechanism ◽  
G1 Arrest ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Pole Body ◽  
In Cells

The regulation and timing of spindle pole body (SPB) duplication and maturation in fission yeast was examined by transmission electron microscopy. When cells are arrested at G1 by nitrogen starvation, the SPB is unduplicated. On release from G1, the SPBs were duplicated after 1–2 h. In cells arrested at S by hydroxyurea, SPBs are duplicated but not mature. In G1 arrest/release experiments with cdc2.33 cells at the restrictive temperature, SPBs remained single, whereas in cells at the permissive temperature, SPBs were duplicated. In cdc10 mutant cells, the SPBs seem not only to be duplicated but also to undergo partial maturation, including invagination of the nuclear envelope underneath the SPB. There may be an S-phase–specific inhibitor of SPB maturation whose expression is under control of cdc10+. This model was examined by induction of overreplication of the genome by overexpression of rum1p or cdc18p. In cdc18p-overexpressing cells, the SPBs are duplicated but not mature, suggesting that cdc18p is one component of this feedback mechanism. In contrast, cells overexpressing rum1p have large, deformed SPBs accompanied by other features of maturation and duplication. We propose a feedback mechanism for maturation of the SPB that is coupled with exit from S to trigger morphological changes.

scholarly journals MOB1, an Essential Yeast Gene Required for Completion of Mitosis and Maintenance of Ploidy

1998 ◽  
Vol 9 (1) ◽  
pp. 29-46 ◽  
Author(s):  
Francis C. Luca ◽  
Mark Winey
Keyword(s):  
Genetic Interaction ◽  
Sequence Similarity ◽  
Spindle Pole Body ◽  
Mitotic Checkpoint ◽  
Spindle Pole ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Yeast Gene ◽  
Pole Body ◽  
Yeast Genes

Mob1p is an essential Saccharomyces cerevisiaeprotein, identified from a two-hybrid screen, that binds Mps1p, a protein kinase essential for spindle pole body duplication and mitotic checkpoint regulation. Mob1p contains no known structural motifs; however MOB1 is a member of a conserved gene family and shares sequence similarity with a nonessential yeast gene,MOB2. Mob1p is a phosphoprotein in vivo and a substrate for the Mps1p kinase in vitro. Conditional alleles ofMOB1 cause a late nuclear division arrest at restrictive temperature. MOB1 exhibits genetic interaction with three other yeast genes required for the completion of mitosis,LTE1, CDC5, and CDC15 (the latter two encode essential protein kinases). Most haploid mutantmob1 strains also display a complete increase in ploidy at permissive temperature. The mechanism for the increase in ploidy may occur through MPS1 function. One mob1strain, which maintains stable haploidy at both permissive and restrictive temperature, diploidizes at permissive temperature when combined with the mps1–1 mutation. Strains containingmob2Δ also display a complete increase in ploidy when combined with the mps1-1 mutation. Perhaps in addition to, or as part of, its essential function in late mitosis, MOB1 is required for a cell cycle reset function necessary for the initiation of the spindle pole body duplication.

Distinct nuclear and spindle pole body populations of cyclin–cdc2 in fission yeast

Nature ◽  
1990 ◽  
Vol 347 (6294) ◽  
pp. 680-682 ◽  
Author(s):  
Caroline E. Alfa ◽  
Bernard Ducommun ◽  
David Beach ◽  
Jeremy S. Hyams
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

scholarly journals Studies concerning the temporal and genetic control of cell polarity in Saccharomyces cerevisiae.

1991 ◽  
Vol 114 (3) ◽  
pp. 515-532 ◽  
Author(s):  
M Snyder ◽  
S Gehrung ◽  
B D Page
Keyword(s):  
Cell Cycle ◽  
Cell Polarity ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Cells ◽  
Cell Cycle Distribution ◽  
Restrictive Temperature ◽  
Microtubule Bundle ◽  
Pole Body ◽  
Capture Site

The establishment of cell polarity was examined in the budding yeast, S. cerevisiae. The distribution of a polarized protein, the SPA2 protein, was followed throughout the yeast cell cycle using synchronized cells and cdc mutants. The SPA2 protein localizes to a patch at the presumptive bud site of G1 cells. Later it concentrates at the bud tip in budded cells. At cytokinesis, the SPA2 protein is at the neck between the mother and daughter cells. Analysis of unbudded haploid cells has suggested a series of events that occurs during G1. The SPA2 patch is established very early in G1, while the spindle pole body residues on the distal side of the nucleus. Later, microtubules emanating from the spindle pole body intersect the SPA2 crescent, and the nucleus probably rotates towards the SPA2 patch. By middle G1, most cells contain the SPB on the side of the nucleus proximal to the SPA2 patch, and a long extranuclear microtubule bundle intersects this patch. We suggest that a microtubule capture site exists in the SPA2 staining region that stabilizes the long microtubule bundle; this capture site may be responsible for rotation of the nucleus. Cells containing a polarized distribution of the SPA2 protein also possess a polarized distribution of actin spots in the same region, although the actin staining is much more diffuse. Moreover, cdc4 mutants, which form multiple buds at the restrictive temperature, exhibit simultaneous staining of the SPA2 protein and actin spots in a subset of the bud tips. spa2 mutants contain a polarized distribution of actin spots, and act1-1 and act1-2 mutants often contain a polarized distribution of the SPA2 protein suggesting that the SPA2 protein is not required for localization of the actin spots and the actin spots are not required for localization of the SPA2 protein. cdc24 mutants, which fail to form buds at the restrictive temperature, fail to exhibit polarized localization of the SPA2 protein and actin spots, indicating that the CDC24 protein is directly or indirectly responsible for controlling the polarity of these proteins. Based on the cell cycle distribution of the SPA2 protein, a "cytokinesis tag" model is proposed to explain the mechanism of the non-random positioning of bud sites in haploid yeast cells.

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 A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast

2017 ◽  
Vol 28 (25) ◽  
pp. 3647-3659 ◽  
Author(s):  
Masashi Yukawa ◽  
Tomoki Kawakami ◽  
Masaki Okazaki ◽  
Kazunori Kume ◽  
Ngang Heok Tang ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Spindle Pole Body ◽  
Spindle Assembly ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Bipolar Spindle ◽  
Pole Body ◽  
Cross Linker ◽  
Spindle Elongation

Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

Two-hybrid search for proteins that interact with Sad1 and Kms1, two membrane-bound components of the spindle pole body in fission yeast

2003 ◽  
Vol 270 (6) ◽  
pp. 449-461 ◽  
Author(s):  
F. Miki ◽  
A. Kurabayashi ◽  
Y. Tange ◽  
K. Okazaki ◽  
M. Shimanuki ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Hybrid Search ◽  
Pole Body ◽  
Membrane Bound ◽  
Two Hybrid

scholarly journals Cut1/separase C-terminus affects spindle pole body positioning in interphase of fission yeast: pointed nuclear formation

2002 ◽  
Vol 7 (11) ◽  
pp. 1113-1124 ◽  
Author(s):  
Takahiro Nakamura ◽  
Koji Nagao ◽  
Yukinobu Nakaseko ◽  
Mitsuhiro Yanagida
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
C Terminus ◽  
Body Positioning

scholarly journals Role of calmodulin and Spc110p interaction in the proper assembly of spindle pole body compenents.

1996 ◽  
Vol 133 (1) ◽  
pp. 111-124 ◽  
Author(s):  
H A Sundberg ◽  
L Goetsch ◽  
B Byers ◽  
T N Davis
Keyword(s):  
Spindle Pole Body ◽  
Spindle Pole ◽  
Immunofluorescent Staining ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Nonpermissive Temperature ◽  
Carboxy Terminus ◽  
Calmodulin Binding ◽  
Pole Body ◽  
Mutant Cells

Previously we demonstrated that calmodulin binds to the carboxy terminus of Spc110p, an essential component of the Saccharomyces cerevisiae spindle pole body (SPB), and that this interaction is required for chromosome segregation. Immunoelectron microscopy presented here shows that calmodulin and thus the carboxy terminus of Spc110p localize to the central plaque. We created temperature-sensitive SPC110 mutations by combining PCR mutagenesis with a plasmid shuffle strategy. The temperature-sensitive allele spc110-220 differs from wild type at two sites. The cysteine 911 to arginine mutation resides in the calmodulin-binding site and alone confers a temperature-sensitive phenotype. Calmodulin overproduction suppresses the temperature sensitivity of spc110-220. Furthermore, calmodulin levels at the SPB decrease in the mutant cells at the restrictive temperature. Thus, calmodulin binding to Spc110-220p is defective at the nonpermissive temperature. Synchronized mutant cells incubated at the nonpermissive temperature arrest as large budded cells with a G2 content of DNA and suffer considerable lethality. Immunofluorescent staining demonstrates failure of nuclear DNA segregation and breakage of many spindles. Electron microscopy reveals an aberrant nuclear structure, the intranuclear microtubule organizer (IMO), that differs from a SPB but serves as a center of microtubule organization. The IMO appears during nascent SPB formation and disappears after SPB separation. The IMO contains both the 90-kD and the mutant 110-kD SPB components. Our results suggest that disruption of the calmodulin Spc110p interaction leads to the aberrant assembly of SPB components into the IMO, which in turn perturbs spindle formation.

scholarly journals Nuclear shape, growth and integrity in the closed mitosis of fission yeast depend on the Ran-GTPase system, the spindle pole body and the endoplasmic reticulum

2009 ◽  
Vol 122 (14) ◽  
pp. 2464-2472 ◽  
Author(s):  
Y. Gonzalez ◽  
K. Meerbrey ◽  
J. Chong ◽  
Y. Torii ◽  
N. N. Padte ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Nuclear Shape ◽  
Ran Gtpase ◽  
Pole Body
Sign in / Sign up

Export Citation Format

Share Document