scholarly journals Phosphatidylethanolamine Is Required for Normal Cell Morphology and Cytokinesis in the Fission Yeast Schizosaccharomyces pombe

2009 ◽  
Vol 8 (5) ◽  
pp. 790-799 ◽  
Author(s):  
Jun Luo ◽  
Yasuhiro Matsuo ◽  
Galina Gulis ◽  
Haylee Hinz ◽  
Jana Patton-Vogt ◽  
...  
Keyword(s):  
Cell Growth ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Minimal Medium ◽  
Growth Media ◽  
Decarboxylase Activity ◽  
Rich Medium ◽  
Wild Type ◽  
Cellular Functions ◽  
Kennedy Pathway

ABSTRACT To investigate the contributions of phosphatidylethanolamine to the growth and morphogenesis of the fission yeast Schizosaccharomyces pombe, we have characterized three predicted genes in this organism, designated psd1, psd2, and psd3, encoding phosphatidylserine decarboxylases, which catalyze the conversion of phosphatidylserine to phosphatidylethanolamine in both eukaryotic and prokaryotic organisms. S. pombe mutants carrying deletions in any one or two psd genes are viable in complex rich medium and synthetic defined minimal medium. However, mutants carrying deletions in all three psd genes (psd1-3Δ mutants) grow slowly in rich medium and are inviable in minimal medium, indicating that the psd1 to psd3 gene products share overlapping essential cellular functions. Supplementation of growth media with ethanolamine, which can be converted to phosphatidylethanolamine by the Kennedy pathway, restores growth to psd1-3Δ cells in minimal medium, indicating that phosphatidylethanolamine is essential for S. pombe cell growth. psd1-3Δ cells produce lower levels of phosphatidylethanolamine than wild-type cells, even in medium supplemented with ethanolamine, indicating that the Kennedy pathway can only partially compensate for the loss of phosphatidylserine decarboxylase activity in S. pombe. psd1-3Δ cells appear morphologically indistinguishable from wild-type S. pombe cells in medium supplemented with ethanolamine, but when cultured in nonsupplemented medium, they produce high frequencies of abnormally shaped cells as well as cells exhibiting severe septation defects, including multiple, mispositioned, deformed, and misoriented septa. Our results demonstrate that phosphatidylethanolamine is essential for cell growth and for normal cytokinesis and cellular morphogenesis in S. pombe, and they illustrate the usefulness of this model eukaryote for investigating potentially conserved biological and molecular functions of phosphatidylethanolamine.

scholarly journals Isolation of protein glycosylation mutants in the fission yeast Schizosaccharomyces pombe.

1995 ◽  
Vol 6 (5) ◽  
pp. 485-496 ◽  
Author(s):  
K M Huang ◽  
M D Snider
Keyword(s):  
Cell Wall ◽  
Acid Phosphatase ◽  
Cell Growth ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Electrophoretic Mobility ◽  
Protein Glycosylation ◽  
Wild Type ◽  
Glycoprotein Synthesis ◽  
Lectin Staining

We have isolated mutants in the fission yeast Schizosaccharomyces pombe that are defective in protein glycosylation. A collection of osmotically sensitive mutants was prepared and screened for glycosylation defects using lectin staining as an assay. Mutants singly defective in four glycoprotein synthesis genes (gps1-4) were isolated, all of which bind less galactose-specific lectin. Acid phosphatase and other glycoproteins from the gps mutants have increased electrophoretic mobility, suggesting that these mutants make glycans of reduced size. N-linked glycan analysis revealed that terminal oligosaccharide modification is defective in the gps1 and gps2 mutants. Both mutants synthesize the Man9GlcNAc2 core glycan but have reduced amounts of larger structures. Modified core glycans from gps1 cells have normal amounts of galactose (Gal) residues, but reduced amounts of Man, consistent with a defect in a Golgi mannosyltransferase in this mutant. In contrast, N-linked oligosaccharides from gps2 mutants have much less Gal than wild type, because of reduced levels of the Gal donor, UDP-Gal. This reduction is caused by decreased activity of UDP-glucose 4-epimerase, which synthesizes UDP-Gal. Neither the gps1 or gps2 mutations are lethal, although the cells grow at reduced rates. These findings suggest that S. pombe cells can survive with incompletely glycosylated cell wall glycoproteins. In particular, these results suggest that Gal, which comprises approximately 30% by weight of cell wall glycoprotein glycans, is not crucial for cell growth or survival.

scholarly journals Disruption of aldA Influences the Developmental Process in Myxococcus xanthus

2000 ◽  
Vol 182 (2) ◽  
pp. 546-550 ◽  
Author(s):  
Mandy J. Ward ◽  
Helen Lew ◽  
David R. Zusman
Keyword(s):  
Gene Disruption ◽  
Minimal Medium ◽  
Developmental Process ◽  
Myxococcus Xanthus ◽  
Protein Sequences ◽  
Rich Medium ◽  
Wild Type ◽  
Rate Of Growth ◽  
Alanine Dehydrogenase ◽  
Developmental Conditions

ABSTRACT Previously, we identified a gene (aldA) fromMyxococcus xanthus, which we suggested encoded the enzyme alanine dehydrogenase on the basis of similarity to known Ald protein sequences (M. J. Ward, H. Lew, A. Treuner-Lange, and D. R. Zusman, J. Bacteriol. 180:5668–5675, 1998). In this study, we have confirmed that aldA does encode a functional alanine dehydrogenase, since it catalyzes the reversible conversion of alanine to pyruvate and ammonia. Whereas an aldA gene disruption mutation did not significantly influence the rate of growth or spreading on a rich medium, AldA was required for growth on a minimal medium containing l-alanine as the major source of carbon. Under developmental conditions, the aldA mutation caused delayed aggregation in both wild-type (DZ2) and FB (DZF1) strains. Poorly formed aggregates and reduced levels of spores were apparent in the DZ2 aldA mutant, even after prolonged development.

Human p53 inhibits growth in Schizosaccharomyces pombe

1992 ◽  
Vol 12 (4) ◽  
pp. 1405-1411
Author(s):  
J R Bischoff ◽  
D Casso ◽  
D Beach
Keyword(s):  
Amino Acid ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Amino Acid Residue ◽  
Mechanism Of Action ◽  
Mammalian Cells ◽  
Simple System ◽  
Wild Type ◽  
Dominant Mutation ◽  
Mutant Forms

Overexpression of wild-type p53 in mammalian cells blocks growth. We show here that the overexpression of wild-type human p53 in the fission yeast Schizosaccharomyces pombe also blocks growth, whereas the overexpression of mutant forms of p53 does not. The p53 polypeptide is located in the nucleus and is phosphorylated at both the cdc2 site and the casein kinase II site in S. pombe. A new dominant mutation of p53, resulting in the change of a cysteine to an arginine at amino acid residue 141, was identified. The results presented here demonstrate that S. pombe could provide a simple system for studying the mechanism of action of human p53.

scholarly journals Intramitotic controls in the fission yeast Schizosaccharomyces pombe: the effect of cell size on spindle length and the timing of mitotic events.

1990 ◽  
Vol 110 (5) ◽  
pp. 1617-1621 ◽  
Author(s):  
I M Hagan ◽  
P N Riddle ◽  
J S Hyams
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Average Length ◽  
Nuclear Migration ◽  
Yeast Cells ◽  
Reverse Direction ◽  
Wild Type ◽  
Spindle Elongation ◽  
Anaphase B ◽  
In Cells

We have used a new cinemicroscopy technique in combination with antitubulin immunofluorescence microscopy to investigate the timing of mitotic events in cells of the fission yeast Schizosaccharomyces pombe having lengths at division between 7 and 60 microns. Wild-type fission yeast cells divide at a length of 14 microns. Separation of daughter nuclei (anaphase B) proceeds at a rate of 1.6 +/- 0.2 microns min-1, until the spindle extends the length of the cell. Coincident with spindle depolymerization, the nuclei reverse direction and take up positions that will become the center of the two daughter cells. This post-mitotic nuclear migration occurs at a rate of 1.4 +/- 0.5 microns-1. In cells in which the weel+ gene is overexpressed fivefold and that have an average length at mitosis of 28 microns, the rate of nuclear separation was only slightly reduced but, as spindles in these cells measure 20-22 microns, the duration of anaphase B was extended by approximately 40%. By contrast, in the mutant weel.50, which divides at 7 microns, both the rate and duration of anaphase B were indistinguishable from wild type. Nuclei reach the ends of these cells earlier but remain there until a point corresponding to the time of postmitotic nuclear migration in wild type. Thus, the events of mitosis can be extended but not abbreviated. These results are discussed in terms of a mitotic termination control that monitors many different events, one of which is spindle elongation.

scholarly journals Methionine Induces Sexual Development in the Fission Yeast Schizosaccharomyces pombe via anste11-Dependent Signalling Pathway

1998 ◽  
Vol 180 (23) ◽  
pp. 6338-6341 ◽  
Author(s):  
Anne-Marie Schweingruber ◽  
Norma Hilti ◽  
Eleonore Edenharter ◽  
M. Ernst Schweingruber
Keyword(s):  
Cyclic Amp ◽  
Stationary Phase ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Development ◽  
Minimal Medium ◽  
Signalling Pathway ◽  
Intracellular Camp

ABSTRACT Methionine added to minimal medium overcomes the repressing effects of ammonium and cyclic AMP (cAMP) on sexual development and efficiently induces mating and sporulation in homothallic strains ofSchizosaccharomyces pombe. In heterothallic strains it induces G1 arrest when cells enter stationary phase. We show that methionine reduces the intracellular cAMP pool and induces the expression of at least two cAMP-repressible genes, includingfbp1 and ste11. The easiest interpretation of the results is that methionine induces sexual development via a cAMP-dependent ste11 signalling pathway.

scholarly journals Cell Surface Galactosylation Is Essential for Nonsexual Flocculation in Schizosaccharomyces pombe

1999 ◽  
Vol 181 (4) ◽  
pp. 1356-1359 ◽  
Author(s):  
Naotaka Tanaka ◽  
Atsuro Awai ◽  
M. Shah Alam Bhuiyan ◽  
Kiyotaka Fujita ◽  
Hiroshi Fukui ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Cell Surface ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Wild Type ◽  
Liquid Media ◽  
Calcium Dependent ◽  
Yeast Mutants

ABSTRACT We have isolated fission yeast mutants that constitutively flocculate upon growth in liquid media. One of these mutants, thegsf1 mutant, was found to cause dominant, nonsexual, and calcium-dependent aggregation of cells into flocs. Its flocculation was inhibited by the addition of galactose but was not affected by the addition of mannose or glucose, unlike Saccharomyces cerevisiae FLO mutants. The gsf1 mutant coflocculated withSchizosaccharomyces pombe wild-type cells, while no coflocculation was found with galactose-deficient (gms1Δ) cells. Moreover, flocculation of the gsf1 mutant was also inhibited by addition of cell wall galactomannan from wild-type cells but not from gms1Δ cells. These results suggested that galactose residues in the cell wall glycoproteins may be receptors ofgsf1-mediated flocculation, and therefore cell surface galactosylation is required for nonsexual flocculation in S. pombe.

Pseudo-exponential growth in length of the fission yeast, Schizosaccharomyces pombe

1988 ◽  
Vol 34 (12) ◽  
pp. 1338-1343 ◽  
Author(s):  
Hisao Miyata ◽  
Machiko Miyata ◽  
Byron F. Johnson
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Exponential Growth ◽  
Linear Growth ◽  
Normal Growth ◽  
Growth Patterns ◽  
Birth Length ◽  
Yeast Cells ◽  
Wild Type ◽  
Constant Length

The growth patterns of individual cells of the fission yeast (Schizosaccharomyces pombe wild-type cells, strain 972 h−; cells exposed to hydroxyurea; and cdc mutants, 11-123, 2-33) were investigated by time-lapse photomicrography. Wild-type cells showed one, two, or three linear-growth segments followed by a constant-length stage. Cells with two segments were most frequent. Hydroxyurea cells that divided as oversized cells (about three times the birth length) had three linear-growth segments in a cycle. Mutant cdc11-123 cells did not divide but had a constant-length stage separating the cycles; both the first and second cycles consisted of two linear-growth segments, and cells were oversized at the second constant-length stage (about 3.5 times the birth length). Elongating cdc2-33 cells that did not divide and were oversized (about five times the birth length) while under observation, showed four linear-growth segments. Cells of all strains showed 30 to 40% increase in growth rate at the rate-change point and maintained approximate exponential (pseudo-exponential) growth. We conclude that the normal growth pattern of individual fission-yeast cells is the pseudo-exponential pattern.

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