scholarly journals Saccharomyces cerevisiae MPS2Encodes a Membrane Protein Localized at the Spindle Pole Body and the Nuclear Envelope

1999 ◽  
Vol 10 (7) ◽  
pp. 2393-2406 ◽  
Author(s):  
Marı́a de la Cruz Muñoz-Centeno ◽  
Susan McBratney ◽  
Antonio Monterrosa ◽  
Breck Byers ◽  
Carl Mann ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Protein ◽  
Nuclear Envelope ◽  
Fluorescent Protein ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body ◽  
Monopolar Spindle

The MPS2 (monopolar spindle two) gene is one of several genes required for the proper execution of spindle pole body (SPB) duplication in the budding yeast Saccharomyces cerevisiae ( Winey et al., 1991 ). We report here that the MPS2 gene encodes an essential 44-kDa protein with two putative coiled-coil regions and a hydrophobic sequence. Although MPS2 is required for normal mitotic growth, some null strains can survive; these survivors exhibit slow growth and abnormal ploidy. The MPS2 protein was tagged with nine copies of the myc epitope, and biochemical fractionation experiments show that it is an integral membrane protein. Visualization of a green fluorescent protein (GFP) Mps2p fusion protein in living cells and indirect immunofluorescence microscopy of 9xmyc-Mps2p revealed a perinuclear localization with one or two brighter foci of staining corresponding to the SPB. Additionally, immunoelectron microscopy shows that GFP-Mps2p localizes to the SPB. Our analysis suggests that Mps2p is required as a component of the SPB for insertion of the nascent SPB into the nuclear envelope.

scholarly journals NDC1: a nuclear periphery component required for yeast spindle pole body duplication

1993 ◽  
Vol 122 (4) ◽  
pp. 743-751 ◽  
Author(s):  
M Winey ◽  
MA Hoyt ◽  
C Chan ◽  
L Goetsch ◽  
D Botstein ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Mitotic Spindle ◽  
Nuclear Periphery ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Immunofluorescent Localization ◽  
Pole Body ◽  
Acid Protein ◽  
Monopolar Spindle ◽  
Mutant Cells

The spindle pole body (SPB) of Saccharomyces cerevisiae serves as the centrosome in this organism, undergoing duplication early in the cell cycle to generate the two poles of the mitotic spindle. The conditional lethal mutation ndc1-1 has previously been shown to cause asymmetric segregation, wherein all the chromosomes go to one pole of the mitotic spindle (Thomas, J. H., and D. Botstein. 1986. Cell. 44:65-76). Examination by electron microscopy of mutant cells subjected to the nonpermissive temperature reveals a defect in SPB duplication. Although duplication is seen to occur, the nascent SPB fails to undergo insertion into the nuclear envelope. The parental SPB remains functional, organizing a monopolar spindle to which all the chromosomes are presumably attached. Order-of-function experiments reveal that the NDC1 function is required in G1 after alpha-factor arrest but before the arrest caused by cdc34. Molecular analysis shows that the NDC1 gene is essential and that it encodes a 656 amino acid protein (74 kD) with six or seven putative transmembrane domains. This evidence for membrane association is further supported by immunofluorescent localization of the NDC1 product to the vicinity of the nuclear envelope. These findings suggest that the NDC1 protein acts within the nuclear envelope to mediate insertion of the nascent SPB.

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.

scholarly journals The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint.

1996 ◽  
Vol 132 (1) ◽  
pp. 111-123 ◽  
Author(s):  
E Weiss ◽  
M Winey
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Spindle Pole Body ◽  
Mitotic Checkpoint ◽  
Spindle Pole ◽  
Normal Cycle ◽  
Pole Body ◽  
Monopolar Spindle ◽  
M Phase

M-phase checkpoints inhibit cell division when mitotic spindle function is perturbed. Here we show that the Saccharomyces cerevisiae MPS1 gene product, an essential protein kinase required for spindle pole body (SPB) duplication (Winey et al., 1991; Lauze et al., 1995), is also required for M-phase check-point function. In cdc31-2 and mps2-1 mutants, conditional failure of SPB duplication results in cell cycle arrest with high p34CDC28 kinase activity that depends on the presence of the wild-type MAD1 checkpoint gene, consistent with checkpoint arrest of mitosis. In contrast, mps1 mutant cells fail to duplicate their SPBs and do not arrest division at 37 degrees C, exhibiting a normal cycle of p34CDC28 kinase activity despite the presence of a monopolar spindle. Double mutant cdc31-2, mps1-1 cells also fail to arrest mitosis at 37 degrees C, despite having SPB structures similar to cdc31-2 single mutants as determined by EM analysis. Arrest of mitosis upon microtubule depolymerization by nocodazole is also conditionally absent in mps1 strains. This is observed in mps1 cells synchronized in S phase with hydroxyurea before exposure to nocodazole, indicating that failure of checkpoint function in mps1 cells is independent of SPB duplication failure. In contrast, hydroxyurea arrest and a number of other cdc mutant arrest phenotypes are unaffected by mps1 alleles. We propose that the essential MPS1 protein kinase functions both in SPB duplication and in a mitotic checkpoint monitoring spindle integrity.

Centromere clustering is a major determinant of yeast interphase nuclear organization

2000 ◽  
Vol 113 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Q.W. Jin ◽  
J. Fuchs ◽  
J. Loidl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Organization ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genome Separation ◽  
Pole Body ◽  
Opposite Pole ◽  
Somatic Pairing ◽  
Higher Eukaryotes

During interphase in the budding yeast, Saccharomyces cerevisiae, centromeres are clustered near one pole of the nucleus as a rosette with the spindle pole body at its hub. Opposite to the centromeric pole is the nucleolus. Chromosome arms extend outwards from the centromeric pole and are preferentially directed towards the opposite pole. Centromere clustering is reduced by the ndc10 mutation, which affects a kinetochore protein, and by the microtubule poison nocodazole. This suggests that clustering is actively maintained or enforced by the association of centromeres with microtubules throughout interphase. Unlike the Rabl-orientation known from many higher eukaryotes, centromere clustering in yeast is not only a relic of anaphase chromosome polarization, because it can be reconstituted without the passage of cells through anaphase. Within the rosette, homologous centromeres are not arranged in a particular order that would suggest somatic pairing or genome separation.

scholarly journals The S. pombe mitotic regulator Cut12 promotes spindle pole body activation and integration into the nuclear envelope

2009 ◽  
Vol 185 (5) ◽  
pp. 875-888 ◽  
Author(s):  
Victor A. Tallada ◽  
Kenji Tanaka ◽  
Mitsuhiro Yanagida ◽  
Iain M. Hagan
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Cell Cycle Control ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Loss Of Function ◽  
Pole Body ◽  
Cytoplasmic Structure ◽  
Monopolar Spindle ◽  
Nuclear Component

The fission yeast spindle pole body (SPB) comprises a cytoplasmic structure that is separated from an ill-defined nuclear component by the nuclear envelope. Upon mitotic commitment, the nuclear envelope separating these domains disperses as the two SPBs integrate into a hole that forms in the nuclear envelope. The SPB component Cut12 is linked to cell cycle control, as dominant cut12.s11 mutations suppress the mitotic commitment defect of cdc25.22 cells and elevated Cdc25 levels suppress the monopolar spindle phenotype of cut12.1 loss of function mutations. We show that the cut12.1 monopolar phenotype arises from a failure to activate and integrate the new SPB into the nuclear envelope. The activation of the old SPB was frequently delayed, and its integration into the nuclear envelope was defective, resulting in leakage of the nucleoplasm into the cytoplasm through large gaps in the nuclear envelope. We propose that these activation/integration defects arise from a local deficiency in mitosis-promoting factor activation at the new SPB.

scholarly journals Changes in the Nuclear Envelope Environment Affect Spindle Pole Body Duplication in Saccharomyces cerevisiae

Genetics ◽  
2010 ◽  
Vol 186 (3) ◽  
pp. 867-883 ◽  
Author(s):  
Keren L. Witkin ◽  
Jennifer M. Friederichs ◽  
Orna Cohen-Fix ◽  
Sue L. Jaspersen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Envelope ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

scholarly journals Mutations in yeast calmodulin cause defects in spindle pole body functions and nuclear integrity.

1992 ◽  
Vol 119 (6) ◽  
pp. 1625-1639 ◽  
Author(s):  
G H Sun ◽  
A Hirata ◽  
Y Ohya ◽  
Y Anraku
Keyword(s):  
Nuclear Envelope ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Fixation Method ◽  
Chromosome Loss ◽  
Permissive Temperature ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Pole Body ◽  
Monopolar Spindle

Yeast calmodulin (CaM) is required for the progression of nuclear division (Ohya, Y. and Y. Anraku. 1989. Curr. Genet. 15:113-120), although the precise mechanism and physiological role of CaM in this process are unclear. In this paper we have characterized the phenotype caused by a temperature-sensitive lethal mutation (cmdl-101) in the yeast CaM. The cmdl-101 mutation expresses a carboxyl-terminal half of the yeast CaM (Met72-Cys147) under the control of an inducible GAL1 promoter. Incubation of the cmdl-101 cells at a nonpermissive temperature causes a severe defect in chromosome segregation. The rate of chromosome loss in the cmdl-101 mutant is higher than wild-type cell even at permissive temperature. The primary visible defect observed by immunofluorescence and electron microscopic analyses is that the organization of spindle microtubules is abnormal in the cmdl-101 cells grown at nonpermissive temperature. Majority of budded cells arrested at the high temperature contain only one spindle pole body (SPB), which forms monopolar spindle, whereas the budded cells of the same strain incubated at permissive temperature all contain two SPBs. Using the freeze-substituted fixation method, we found that the integrity of the nuclear morphology of the cmdl-101 mutant cell is significantly disturbed. The nucleus in wild-type cells is round with smooth contours of nuclear envelope. However, the nuclear envelope in the mutant cells appears to be very flexible and forms irregular projections and invaginations that are never seen in wild-type cells. The deformation of the nuclear becomes much more severe as the incubation at nonpermissive temperature continues. The single SPB frequently localizes on the projections or the invaginations of the nuclear envelope. These observations suggest that CaM is required for the functions of SPB and spindle, and the integrity of nucleus.

scholarly journals Analysis of Tub4p, a yeast gamma-tubulin-like protein: implications for microtubule-organizing center function.

1996 ◽  
Vol 134 (2) ◽  
pp. 443-454 ◽  
Author(s):  
L G Marschall ◽  
R L Jeng ◽  
J Mulholland ◽  
T Stearns
Keyword(s):  
Fluorescent Protein ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Dependent Manner ◽  
Protein Fusion ◽  
Microtubule Organizing Center ◽  
Pole Body ◽  
Monopolar Spindle ◽  
Organizing Center ◽  
Gamma Tubulin

gamma-Tubulin is a conserved component of microtubule-organizing centers and is thought to be involved in microtubule nucleation. A recently discovered Saccharomyces cerevisiae gene (TUB4) encodes a tubulin that is related to, but divergent from, gamma-tubulins. TUB4 is essential for cell viability, and epitope-tagged Tub4 protein (Tub4p) is localized to the spindle pole body (Sobel, S.G., and M. Snyder. 1995.J. Cell Biol. 131:1775-1788). We have characterized the expression of TUB4, the association of Tub4p with the spindle pole body, and its role in microtubule organization. Tub4p is a minor protein in the cell, and expression of TUB4 is regulated in a cell cycle-dependent manner. Wild-type Tub4p is localized to the spindle pole body, and a Tub4p-green fluorescent protein fusion is able to associate with a preexisting spindle pole body, suggesting that there is dynamic exchange between cytoplasmic and spindle pole body forms of Tub4p. Perturbation of Tub4p function, either by conditional mutation or by depletion of the protein, results in spindle as well as spindle pole body defects, but does not eliminate the ability of microtubules to regrow from, or remain attached to, the spindle pole body. The spindle pole bodies in tub4 mutant cells duplicate but do not separate, resulting in a monopolar spindle. EM revealed that one spindle pole body of the duplicated pair appears to be defective for the nucleation of microtubules. These results offer insight into the role of gamma-tubulin in microtubule-organizing center function.

Bouquet formation in budding yeast: initiation of recombination is not required for meiotic telomere clustering

1999 ◽  
Vol 112 (5) ◽  
pp. 651-658 ◽  
Author(s):  
E. Trelles-Sticken ◽  
J. Loidl ◽  
H. Scherthan
Keyword(s):  
Saccharomyces Cerevisiae ◽  
In Situ Hybridization ◽  
Time Course ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Conformational State ◽  
Chromosome Territories ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body

Fluorescence in situ hybridization in combination with synaptonemal complex and spindle pole body immunostaining to both spread and structurally preserved nuclei from time course experiments disclosed prominent telomere clustering during meiotic prophase of the yeast Saccharomyces cerevisiae. It was found that centromere clustering, which dominates vegetative nuclear structure, is rapidly lost after induction of meiosis. Telomeres tightly clustered during leptotene/zygotene-equivalent stages in the vicinity of the spindle pole body, giving rise to a classical chromosomal bouquet arrangement. This arrangement dissolved later during prophase. Painting of chromosomes XI revealed that initially compacted chromosome territories adopt an outstretched morphology in bouquet nuclei. This conformational state was associated with alignment and pairing. Chromosome condensation during pachytene rendered condensed and compact bivalents, and dispersed telomeres. Both the spo11 and rad50S recombination mutants formed bouquets, demonstrating that bouquet formation is recombination and synapsis independent.

Sign in / Sign up

Export Citation Format

Share Document