Growth in cell length in the fission yeast Schizosaccharomyces pombe

1985 ◽  
Vol 75 (1) ◽  
pp. 357-376 ◽  
Author(s):  
J.M. Mitchison ◽  
P. Nurse
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Cell Size ◽  
Single Cells ◽  
Temperature Shift ◽  
Time Lapse ◽  
Cell Length ◽  
Wild Type ◽  
Cycle Growth ◽  
A Cell ◽  
Mutant Cells

The cylindrical cells of Schizosaccharomyces pombe grow in length by extension at the ends and not the middle. At the beginning of the cell cycle, growth is restricted to the ‘old end’, which existed in the previous cycle. Later on, the ‘new end’, formed from the septum, starts to grow at a point in the cycle that we have called NETO (‘new end take-off’). Fluorescence microscopy on cells stained with Calcofluor has been used to study NETO in size mutants, in blocked cdc mutants and with different growth temperatures and media. In wild-type cells (strain 972) NETO happens at 0.34 of the cycle with a cell length of 9.5 microns. With size mutants that are smaller at division, NETO takes place at the same size (9.0-9.5 microns) but this is not achieved until later in the cycle. Another control operates in larger size mutants since NETO occurs at the same stage of the cycle (about 0.32) as in wild type but at a larger cell size. This control is probably a requirement to have completed an event in early G2, since most cdc mutant cells blocked before this point in the cycle do not show NETO whereas most of those blocked in late G2 do show it. We conclude that NETO only happens if: (1) the cell length is greater than a critical value of 9.0-9.5 microns; and (2) the cell has traversed the first 0.3-0.35 of the cycle and passed early G2. NETO is delayed in poor media, in which cell size is also reduced. Temperature has little effect on NETO under steady-state conditions, but there is a transient delay for some hours after a temperature shift. NETO is later in another wild-type strain, 132. Time-lapse photomicrography was used to follow the rates of length growth in single cells. Wild-type cells showed two linear segments during the first 75% of the cycle. There was a rate-change point (RCP), coincident with NETO, where the rate of total length extension increased by 35%. This increase was not due simply to the start of new-end growth, since old-end growth slowed down in some cells at the RCP. cdc 11.123 is a mutant in which septation and division is blocked at 35 degrees C but nuclear division continues.(ABSTRACT TRUNCATED AT 400 WORDS)

Synchronisation of mitosis in a cell division cycle mutant of Schizosaccharomyces pombe released from temperature arrest

1982 ◽  
Vol 28 (2) ◽  
pp. 261-264 ◽  
Author(s):  
Stephen M. King ◽  
Jeremy S. Hyams
Keyword(s):  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Temperature Shift ◽  
Cell Plate ◽  
Restrictive Temperature ◽  
C Cells ◽  
Wild Type ◽  
Ultrastructural Morphology ◽  
Synchronous Cultures ◽  
A Cell

When cultures of Schizosaccharomyces pombe cdc 2.33 were shifted to 25 °C, after 5 h at the restrictive temperature of 35 °C, cells entered cycles of synchronous division as judged by the appearance of peaks in the cell plate index at 1.5, 3, and 4.75 h. The timing and ultrastructural morphology of events occurring in such synchronous cultures were examined. Most cells underwent mitosis between 10 and 50 min after the temperature shift, with a maximal value after approximately 30 min. The ultrastructure of mitosis was consistent with previous descriptions of this process in wild-type cells.

The role of the cortical cytoskeleton: F-actin crosslinking proteins protect against osmotic stress, ensure cell size, cell shape and motility, and contribute to phagocytosis and development

1996 ◽  
Vol 109 (11) ◽  
pp. 2679-2691 ◽  
Author(s):  
F. Rivero ◽  
B. Koppel ◽  
B. Peracino ◽  
S. Bozzaro ◽  
F. Siegert ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Cell Size ◽  
Cell Shape ◽  
Developmental Stages ◽  
Osmotic Shock ◽  
Time Lapse ◽  
Wild Type ◽  
Protective Function ◽  
Multicellular Development ◽  
Mutant Cells

We generated Dictyostelium double mutants lacking the two F-actin crosslinking proteins alpha-actinin and gelation factor by inactivating the corresponding genes via homologous recombination. Here we investigated the consequences of these deficiencies both at the single cell level and at the multicellular stage. We found that loss of both proteins severely affected growth of the mutant cells in shaking suspension, and led to a reduction of cell size from 12 microns in wild-type cells to 9 microns in mutant cells. Moreover the cells did not exhibit the typical polarized morphology of aggregating Dictyostelium cells but had a more rounded cell shape, and also exhibited an increased sensitivity towards osmotic shock and a reduced rate of phagocytosis. Development was heavily impaired and never resulted in the formation of fruiting bodies. Expression of developmentally regulated genes and the final developmental stages that were reached varied, however, with the substrata on which the cells were deposited. On phosphate buffered agar plates the cells were able to form tight aggregates and mounds and to express prespore and prestalk cell specific genes. Under these conditions the cells could perform chemotactic signalling and cell behavior was normal at the onset of multicellular development as revealed by time-lapse video microscopy. Double mutant cells were motile but speed was reduced by approximately 30% as compared to wild type. These changes were reversed by expressing the gelation factor in the mutant cells. We conclude that the actin assemblies that are formed and/or stabilized by both F-actin crosslinking proteins have a protective function during osmotic stress and are essential for proper cell shape and motility.

Mild temperature shock alters the transcription of a discrete class of Saccharomyces cerevisiae genes

1983 ◽  
Vol 3 (3) ◽  
pp. 457-465
Author(s):  
C H Kim ◽  
J R Warner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Temperature Shift ◽  
Restrictive Temperature ◽  
Ribosomal Protein Genes ◽  
Wild Type ◽  
Temperature Shock ◽  
Mild Temperature ◽  
Mutant Cells

In Saccharomyces cerevisiae the synthesis of ribosomal proteins declines temporarily after a culture has been subjected to a mild temperature shock, i.e., a shift from 23 to 36 degrees C, each of which support growth. Using cloned genes for several S. cerevisiae ribosomal proteins, we found that the changes in the synthesis of ribosomal proteins parallel the changes in the concentration of mRNA of each. The disappearance and reappearance of the mRNA is due to a brief but severe inhibition of the transcription of each of the ribosomal protein genes, although the total transcription of mRNA in the cells is relatively unaffected by the temperature shock. The precisely coordinated response of these genes, which are scattered throughout the genome, suggests that either they or the enzyme which transcribes them has unique properties. In certain S. cerevisiae mutants, the synthesis of ribosomal proteins never recovers from a temperature shift. Yet both the decline and the resumption of transcription of these genes during the 30 min after the temperature shift are indistinguishable from those in wild-type cells. The failure of the mutant cells to grow at the restrictive temperature appears to be due to their inability to process the RNA transcribed from genes which have introns (Rosbash et al., Cell 24:679-686, 1981), a large proportion of which appear to be ribosomal protein genes.

The kinetics of the B cyclin p56cdc13 and the phosphatase p80cdc25 during the cell cycle of the fission yeast Schizosaccharomyces pombe

1996 ◽  
Vol 109 (6) ◽  
pp. 1647-1653 ◽  
Author(s):  
J. Creanor ◽  
J.M. Mitchison
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Mammalian Cells ◽  
Size Control ◽  
Base Line ◽  
Wild Type ◽  
Main Band ◽  
The Times ◽  
G1 Cells ◽  
Mutant Cells ◽  
Kinetics Of

The levels of the B cyclin p56cdc13 and the phosphatase p80cdc25 have been followed in selection-synchronised cultures of Schizosaccharomyces pombe wild-type and wee1 mutant cells. p56cdc13 has also been followed in induction-synchronised cells of the mutant cdc2-33. The main conclusions are: (1) cdc13 levels in wild-type cells start to rise from base line at about mid-G2, reach a peak before mitosis and then fall slowly through G1. Cells exit mitosis with appreciable levels of cdc13. (2) cdc13 levels in wee1 cells fall to zero in interphase. They also start to rise at the beginning of G2, which may be related to the absence of a mitotic size control. (3) cdc25 starts to rise later and reaches a peak after mitosis. This is not what would be expected from a simple mitotic inducer and suggests that cdc25 has an important function at the end of mitosis. (4) An upper (heavier) band of cdc25 peaks at the same time as the main band but rises and falls more rapidly. If this is a hyperphosphorylated form, its timing shows that it is most unlikely to function in the ways shown for such a form in eggs and mammalian cells. (5) Experiments with the mutant cdc10-129 and with hydroxyurea show that the initial signal to begin synthesis of cdc13 originates at Start. (6) In induction synchrony, where G2 spans across cell division, there is evidence that some events in one cycle cannot start in the previous one. (7) Revised timings are given for the times of mitosis in these cultures.

scholarly journals Analysis of flagellar size control using a mutant of Chlamydomonas reinhardtii with a variable number of flagella.

1982 ◽  
Vol 92 (1) ◽  
pp. 170-175 ◽  
Author(s):  
M R Kuchka ◽  
J W Jarvik
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Cell Size ◽  
Size Control ◽  
Variable Number ◽  
Pool Size ◽  
Precursor Protein ◽  
Wild Type ◽  
Protein Pool ◽  
Mutant Cells ◽  
Pool Sizes

A mutant of Chlamydomonas reinhardtii with a variable number of flagella per cell has been used to investigate flagellar size control. The mutant and wild-type do not differ in cell size nor in flagellar length, yet the size of the intracellular pool of flagellar precursor protein can differ dramatically among individual mutant cells, with, for example, triflagellate cells having three times the pool of monoflagellate cells. Because cells of the same size, but with very different pool sizes, have flagella of identical length, it appears that the concentration of the unassembled flagellar precursor protein pool does not regulate flagellar length. The relation between cell size, pool size, and flagellar length has also been investigated for wild-type cells of different sizes and ploidies. Again, flagellar length appears to be maintained independent of pool size or concentration.

scholarly journals Disease-causing mutation in α-actinin-4 promotes podocyte detachment through maladaptation to periodic stretch

2018 ◽  
Vol 115 (7) ◽  
pp. 1517-1522 ◽  
Author(s):  
Di Feng ◽  
Jacob Notbohm ◽  
Ava Benjamin ◽  
Shijie He ◽  
Minxian Wang ◽  
...  
Keyword(s):  
Direct Consequence ◽  
Adhesion Assay ◽  
Actin Network ◽  
Wild Type ◽  
Spatially Correlated ◽  
Mechanical Responses ◽  
Podocyte Detachment ◽  
A Cell ◽  
Cross Links ◽  
Mutant Cells

α-Actinin-4 (ACTN4) bundles and cross-links actin filaments to confer mechanical resilience to the reconstituted actin network. How this resilience is built and dynamically regulated in the podocyte, and the cause of its failure in ACTN4 mutation-associated focal segmental glomerulosclerosis (FSGS), remains poorly defined. Using primary podocytes isolated from wild-type (WT) and FSGS-causing point mutant Actn4 knockin mice, we report responses to periodic stretch. While WT cells largely maintained their F-actin cytoskeleton and contraction, mutant cells developed extensive and irrecoverable reductions in these same properties. This difference was attributable to both actin material changes and a more spatially correlated intracellular stress in mutant cells. When stretched cells were further challenged using a cell adhesion assay, mutant cells were more likely to detach. Together, these data suggest a mechanism for mutant podocyte dysfunction and loss in FSGS—it is a direct consequence of mechanical responses of a cytoskeleton that is brittle.

scholarly journals The UDP-Glc:Glycoprotein Glucosyltransferase Is Essential for Schizosaccharomyces pombe Viability under Conditions of Extreme Endoplasmic Reticulum Stress

1998 ◽  
Vol 143 (3) ◽  
pp. 625-635 ◽  
Author(s):  
Sandra Fanchiotti ◽  
Fabiana Fernández ◽  
Cecilia D'Alessio ◽  
Armando J. Parodi
Keyword(s):  
Cell Viability ◽  
Schizosaccharomyces Pombe ◽  
Double Mutant ◽  
Expression Vector ◽  
The Other ◽  
Wild Type ◽  
Glucosidase Ii ◽  
Wild Type Phenotype ◽  
Polypeptide Chains ◽  
Mutant Cells

Interaction of monoglucosylated oligosaccharides with ER lectins (calnexin and/or calreticulin) facilitates glycoprotein folding but this interaction is not essential for cell viability under normal conditions. We obtained two distinct single Schizosaccharomyces pombe mutants deficient in either one of the two pathways leading to the formation of monoglucosylated oligosaccharides. The alg6 mutant does not glucosy- late lipid-linked oligosaccharides and transfers Man9GlcNAc2 to nascent polypeptide chains and the gpt1 mutant lacks UDP-Glc:glycoprotein glucosyltransferase (GT). Both single mutants grew normally at 28°C. On the other hand, gpt1/alg6 double-mutant cells grew very slowly and with a rounded morphology at 28°C and did not grow at 37°C. The wild-type phenotype was restored by transfection of the double mutant with a GT-encoding expression vector or by addition of 1 M sorbitol to the medium, indicating that the double mutant is affected in cell wall formation. It is suggested that facilitation of glycoprotein folding mediated by the interaction of monoglucosylated oligosaccharides with calnexin is essential for cell viability under conditions of extreme ER stress such as underglycosylation of proteins caused by the alg6 mutation and high temperature. In contrast, gls2/alg6 double-mutant cells that transfer Man9GlcNAc2 and that are unable to remove the glucose units added by GT as they lack glucosidase II (GII), grew at 37°C and had, when grown at 28°C, a phenotype of growth and morphology almost identical to that of wild-type cells. These results indicate that facilitation of glycoprotein folding mediated by the interaction of calnexin and monoglucosylated oligosaccharides does not necessarily require cycles of reglucosylation–deglucosylation catalyzed by GT and GII.

scholarly journals A temperature-sensitive mutation of the Schizosaccharomyces pombe gene nuc2+ that encodes a nuclear scaffold-like protein blocks spindle elongation in mitotic anaphase.

1988 ◽  
Vol 106 (4) ◽  
pp. 1171-1183 ◽  
Author(s):  
T Hirano ◽  
Y Hiraoka ◽  
M Yanagida
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Gradient Centrifugation ◽  
Metaphase Plate ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Wild Type ◽  
In The Wild ◽  
Spindle Elongation ◽  
Mutant Cells

A temperature-sensitive mutant nuc2-663 of the fission yeast Schizosaccharomyces pombe specifically blocks mitotic spindle elongation at restrictive temperature so that nuclei in arrested cells contain a short uniform spindle (approximately 3-micron long), which runs through a metaphase plate-like structure consisting of three condensed chromosomes. In the wild-type or in the mutant cells at permissive temperature, the spindle is fully extended approximately 15-micron long in anaphase. The nuc2' gene was cloned in a 2.4-kb genomic DNA fragment by transformation, and its complete nucleotide sequence was determined. Its coding region predicts a 665-residues internally repeating protein (76.250 mol wt). By immunoblots using anti-sera raised against lacZ-nuc2+ fused proteins, a polypeptide (designated p67; 67,000 mol wt) encoded by nuc2+ is detected in the wild-type S. pombe extracts; the amount of p67 is greatly increased when multi-copy or high-expression plasmids carrying the nuc2+ gene are introduced into the S. pombe cells. Cellular fractionation and Percoll gradient centrifugation combined with immunoblotting show that p67 cofractionates with nuclei and is enriched in resistant structure that is insoluble in 2 M NaCl, 25 mM lithium 3,5'-diiodosalicylate, and 1% Triton but is soluble in 8 M urea. In nuc2 mutant cells, however, soluble p76, perhaps an unprocessed precursor, accumulates in addition to insoluble p67. The role of nuc2+ gene may be to interconnect nuclear and cytoskeletal functions in chromosome separation.

Isolation of the Schizosaccharomyces pombe RAD54 homologue, rhp54+, a gene involved in the repair of radiation damage and replication fidelity

1996 ◽  
Vol 109 (1) ◽  
pp. 73-81 ◽  
Author(s):  
D.F. Muris ◽  
K. Vreeken ◽  
A.M. Carr ◽  
J.M. Murray ◽  
C. Smit ◽  
...  
Keyword(s):  
Amino Acids ◽  
Schizosaccharomyces Pombe ◽  
Deletion Mutant ◽  
Chromosome Loss ◽  
Recombinational Repair ◽  
Wild Type ◽  
Facs Analysis ◽  
High Level ◽  
Mutant Cells ◽  
Very High

The RAD54 gene of Saccharomyces cerevisiae encodes a putative helicase, which is involved in the recombinational repair of DNA damage. The RAD54 homologue of the fission yeast Schizosaccharomyces pombe, rhp54+, was isolated by using the RAD54 gene as a heterologous probe. The gene is predicted to encode a protein of 852 amino acids. The overall homology between the mutual proteins of the two species is 67% with 51% identical amino acids and 16% similar amino acids. A rhp54 deletion mutant is very sensitive to both ionizing radiation and UV. Fluorescence microscopy of the rhp54 mutant cells revealed that a large portion of the cells are elongated and occasionally contain aberrant nuclei. In addition, FACS analysis showed an increased DNA content in comparison with wild-type cells. Through a minichromosome-loss assay it was shown that the rhp54 deletion mutant has a very high level of chromosome loss. Furthermore, the rhp54 mutation in either a rad17 or a cdc2.3w mutant background (where the S-phase/mitosis checkpoint is absent) shows a significant reduction in viability. It is hypothesized that the rhp54+ gene is involved in the recombinational repair of UV and X-ray damage and plays a role in the processing of replication-specific lesions.

scholarly journals The GTS1 gene, which contains a Gly-Thr repeat, affects the timing of budding and cell size of the yeast Saccharomyces cerevisiae.

1994 ◽  
Vol 14 (8) ◽  
pp. 5569-5578 ◽  
Author(s):  
K Mitsui ◽  
S Yaguchi ◽  
K Tsurugi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Cell Size ◽  
Single Cells ◽  
Exponential Growth Phase ◽  
Restrictive Temperature ◽  
Multicopy Plasmid ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mean Cell Volume

A gene with an open reading frame encoding a protein of 417 amino acid residues with a Gly-Thr repeat was isolated from the yeast Saccharomyces cerevisiae by using synthetic oligonucleotides encoding three Gly-Thr dimers as probes. The deduced amino acid sequence showed partial homology to the clock-affecting gene, per, of Drosophila melanogaster in the regions including the GT repeat. The function of the gene, named GTS1, was examined by characterizing the phenotypes of transformants with different copy numbers of the GTS1 gene produced either by inactivating the GTS1 gene by gene disruption (TM delta gts1) or by transformation with multicopy plasmid pPER119 (TMpGTS1). They grew at similar rates during the exponential growth phase, but the lag phases were shorter for TM delta gts1 and longer for TMpGTS1 cells than that for the wild type. Analyses of their cell cycle parameters using synchronized cells revealed that the unbudding period changed as a function of gene dosage; that is, the periods of TM delta gts1 and TMpGTS1 were about 20% shorter and longer, respectively, than that of the wild-type. Another significant change in the transformants was detected in the distribution of the cell size. The mean cell volume of the TM delta gts1 cells in the unbudded period (single cells) was 27% smaller than that of single wild-type cells, whereas that of single TMpGTS1 cells was 48% larger. Furthermore, in the temperature-sensitive cdc4 mutant, the GTS1 gene affected the timing of budding at the restrictive temperature. Thus, the GTS1 gene product appears to modulate the timing of budding to obtain an appropriate cell size independent of the DNA replication cycle.

Sign in / Sign up

Export Citation Format

Share Document