Transcriptional Compensation for Gene Loss Plays a Minor Role in Maintaining Genetic Robustness in Saccharomyces cerevisiae

Chromosome segregation must be executed accurately during both mitotic and meiotic cell divisions. Sgo1 plays a key role in ensuring faithful chromosome segregation in at least two ways. During meiosis this protein regulates the removal of cohesins, the proteins that hold sister chromatids together, from chromosomes. During mitosis, Sgo1 is required for sensing the absence of tension caused by sister kinetochores not being attached to microtubules emanating from opposite poles. Here we describe a differential requirement for Sgo1 in the segregation of homologous chromosomes and sister chromatids. Sgo1 plays only a minor role in segregating homologous chromosomes at meiosis I. In contrast, Sgo1 is important to bias sister kinetochores toward biorientation. We suggest that Sgo1 acts at sister kinetochores to promote their biorientation.

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Nuclear behaviour and cell wall composition in relation to budding in mutants of the yeast Saccharomyces cerevisiae

Canadian Journal of Botany ◽

10.1139/b86-027 ◽

1986 ◽

Vol 64 (1) ◽

pp. 193-200 ◽

Cited By ~ 4

Author(s):

Mario Lachapelle ◽

E. Roger Boothroyd

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Spindle Pole ◽

Minor Role ◽

Temperature Sensitive ◽

Yeast Saccharomyces Cerevisiae ◽

Bud Emergence ◽

Spindle Elongation ◽

10 Nm Filaments ◽

A Minor

A temperature-sensitive, cell division cycle mutant (cdc24–1) and karyogamy-deficient (kar1) mutant of Saccharomyces cerevisiae, both of which can produce binucleate or multinucleate cells, were used to study certain aspects of budding, after fluorescent staining for mannan, chitin, and nuclei (DNA). In most binucleate cells the two nuclei lay close together and divided into the same bud. In a few, however, the nuclei were far apart and one or two buds were formed, each proximal to a nucleus. The proximity of daughter nuclei in most blocked cdc24–1 cells suggests a role for the CDC24 gene product in spindle elongation. The relationship between the nuclei and the number and location of buds supports the theory of a preponderant role for the nucleus in budding. Although buds develop preferentially in regions of low chitin content in kar1 heterokaryons, the ability of cdc24–1 cells to bud even with a uniformly high content of chitin and mannan suggests a minor role for these cell wall constituents in determining the sites of bud emergence. The chitin ring is not needed for bud emergence but seems to play a role in normal bud development and in septum formation. Electron microscopy of cdc24–1 cells blocked (37 °C) for 8 h and released (23 °C) for 30 min showed morphologically normal spindle pole bodies, cytoplasmic microtubules, and intranuclear spindles. Although the chitin ring was absent, the ring of 10-nm filaments was present, consistent with its proposed role in bud emergence.

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C-terminal HA tags compromise function and exacerbate phenotypes of Saccharomyces cerevisiae Bloom’s helicase homolog Sgs1 SUMOylation-associated mutants

10.1101/2020.04.23.058578 ◽

2020 ◽

Author(s):

Matan Cohen ◽

Michael Lichten

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Mitotic Cell ◽

Minor Role ◽

Mitotic Cell Cycle ◽

Human Influenza ◽

Wild Type ◽

Epitope Tag ◽

Influenza Hemagglutinin ◽

A Minor

AbstractThe Sgs1 helicase and Top3-Rmi1 decatenase form a complex that affects homologous recombination outcomes during the mitotic cell cycle and during meiosis. Previous studies have reported that Sgs1-Top3-Rmi1 function is regulated by SUMOylation that is catalyzed by the Smc5-Smc6-Mms21 complex. These studies used strains in which SGS1 was C-terminally tagged with three or six copies of a human influenza hemagglutinin-derived epitope tag (3HA and 6HA). They identified SGS1 mutants that affect its SUMOylation, which we will refer to as SGS1 SUMO-site mutants. In previous work, these mutants showed phenotypes consistent with substantial loss of Sgs1-Top3-Rmi1 function during the mitotic cell cycle. We find that the reported phenotypes are largely due to the presence of the HA epitope tags. Untagged SGS1 SUMO-site mutants show either wild-type or weak hypomorphic phenotypes, depending on the assay. These phenotypes are exacerbated by both 6HA and 3HA epitope tags in two different S. cerevisiae strain backgrounds. Importantly, a C-terminal 6HA tag confers strong hypomorphic or null phenotypes on an otherwise wild-type Sgs1 protein. Taken together, these results suggest that the HA epitope tags used in previous studies seriously compromise Sgs1 function. Furthermore, they raise the possibilities either that sufficient SUMOylation of the Sgs1-Top3-Rmi1 complex might still occur in the SUMO-site mutants isolated, or that Smc5-Smc6-Mms21-mediated SUMOylation plays a minor role in the regulation of Sgs1-Top3-Rmi1 during recombination.

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Mec1 and Rad53 Inhibit Formation of Single-Stranded DNA at Telomeres of Saccharomyces cerevisiae cdc13-1 Mutants

Genetics ◽

10.1093/genetics/166.2.753 ◽

2004 ◽

Vol 166 (2) ◽

pp. 753-764 ◽

Cited By ~ 2

Author(s):

Xindan Jia ◽

Ted Weinert ◽

David Lydall

Keyword(s):

Saccharomyces Cerevisiae ◽

Budding Yeast ◽

Minor Role ◽

Clamp Loader ◽

Checkpoint Proteins ◽

Checkpoint Kinases ◽

Sliding Clamp ◽

Telomere Binding Protein ◽

A Minor ◽

Dependent Pathway

Abstract Here we examine the roles of budding-yeast checkpoint proteins in regulating degradation of dsDNA to ssDNA at unprotected telomeres (in Cdc13 telomere-binding protein defective strains). We find that Rad17, Mec3, as well as Rad24, members of the putative checkpoint clamp loader (Rad24) and sliding clamp (Rad17, Mec3) complexes, are important for promoting degradation of dsDNA in and near telomere repeats. We find that Mec1, Rad53, as well as Rad9, have the opposite role: they inhibit degradation. Downstream checkpoint kinases Chk1 and Dun1 play no detectable role in either promoting degradation or inhibiting it. These data suggest, first, that the checkpoint sliding clamp regulates and/or recruits some nucleases for degradation, and, second, that Mec1 activates Rad9 to activate Rad53 to inhibit degradation. Further analysis shows that Rad9 inhibits ssDNA generation by both Mec1/Rad53-dependent and -independent pathways. Exo1 appears to be targeted by the Mec1/Rad53-dependent pathway. Finally, analysis of double mutants suggests a minor role for Mec1 in promoting Rad24-dependent degradation of dsDNA. Thus, checkpoint proteins orchestrate carefully ssDNA production at unprotected telomeres.

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Genetic Analysis of the TOR Pathway in Aspergillus nidulans

Eukaryotic Cell ◽

10.1128/ec.4.9.1595-1598.2005 ◽

2005 ◽

Vol 4 (9) ◽

pp. 1595-1598 ◽

Cited By ~ 35

Author(s):

Gregory J. Fitzgibbon ◽

Igor Y. Morozov ◽

Meriel G. Jones ◽

Mark X. Caddick

Keyword(s):

Saccharomyces Cerevisiae ◽

Genetic Analysis ◽

Aspergillus Nidulans ◽

Minor Role ◽

Tor Signaling ◽

Tor Pathway ◽

Genes Encoding ◽

Tor Kinase ◽

Mutant Phenotypes ◽

A Minor

ABSTRACT We identified five genes encoding components of the TOR signaling pathway within Aspergillus nidulans. Unlike the situation in Saccharomyces cerevisiae, there is only a single Tor kinase, as in plant and animal systems, and mutant phenotypes suggest that the TOR pathway plays only a minor role in regulating nitrogen metabolism.

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Decreased Meiotic Intergenic Recombination and Increased Meiosis I Nondisjunction in exo1 Mutants of Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/156.4.1549 ◽

2000 ◽

Vol 156 (4) ◽

pp. 1549-1557 ◽

Cited By ~ 5

Author(s):

David T Kirkpatrick ◽

John R Ferguson ◽

Thomas D Petes ◽

Lorraine S Symington

Keyword(s):

Saccharomyces Cerevisiae ◽

Homozygous Deletion ◽

Minor Role ◽

Strand Breaks ◽

Exonuclease I ◽

Primary Activity ◽

Dna Mismatches ◽

Intergenic Recombination ◽

A Minor ◽

Meiosis I

Abstract Exonuclease I was originally identified as a 5′ → 3′ deoxyribonuclease present in fractionated extracts of Schizosaccharomyces pombe and Saccharomyces cerevisiae. Genetic analysis of exo1 mutants of both yeasts revealed no major defect in meiosis, suggesting that exonuclease I is unlikely to be the primary activity that processes meiosis-specific double-strand breaks (DSBs). We report here that exo1 mutants of S. cerevisiae exhibit subtle but complex defects in meiosis. Diploids containing a homozygous deletion of EXO1 show decreased spore viability associated with an increase in meiosis I nondisjunction, while intergenic recombination is reduced about twofold. Exo1p functions in the same pathway as Msh5p for intergenic recombination. The length of heteroduplex tracts within the HIS4 gene is unaffected by the exo1 mutation. These results suggest that Exo1p is unlikely to play a major role in processing DSBs to form single-stranded tails at HIS4, but instead appears to promote crossing over to ensure disjunction of homologous chromosomes. In addition, our data indicate that exonuclease I may have a minor role in the correction of large DNA mismatches that occur in heteroduplex DNA during meiotic recombination at the HIS4 locus.

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The Effect of Path Length and Display Size on Memory for Spatial Information

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000137 ◽

2012 ◽

Vol 59 (3) ◽

pp. 147-152 ◽

Cited By ~ 11

Author(s):

Katherine Guérard ◽

Sébastien Tremblay

Keyword(s):

Path Length ◽

Potential Role ◽

Spatial Information ◽

Recall Performance ◽

Minor Role ◽

Length Effect ◽

Serial Memory ◽

Fixed Reference ◽

A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

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Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656198 ◽

1958 ◽

Vol 02 (05/06) ◽

pp. 462-480 ◽

Cited By ~ 1

Author(s):

Marc Verstraete ◽

Patricia A. Clark ◽

Irving S. Wright

Keyword(s):

Prothrombin Time ◽

Anticoagulant Therapy ◽

Factor Vii ◽

Rabbit Brain ◽

Minor Role ◽

Rabbit Lung ◽

Coagulation Mechanism ◽

Time Test ◽

The One ◽

A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

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Produktivkraft als Versprechen

PROKLA Zeitschrift für kritische Sozialwissenschaft ◽

10.32387/prokla.v46i185.135 ◽

2016 ◽

Vol 46 (185) ◽

pp. 621-638 ◽

Cited By ~ 3

Author(s):

Christian Siefkes

Keyword(s):

Private Consumption ◽

Minor Role ◽

Progressive Reduction ◽

Internal Forces ◽

A Minor

The ‘Fragment on Machines’ from Marx’s Grundrisse is often cited as an argument that the internal forces of capitalism will lead to its doom. But the argument that the progressive reduction of labor must doom capitalism lacks a proper foundation, as a comparison with the ‘Schemes of Reproduction’ given in Capital II shows. The latter, however, aren’t fully convincing either. In reality, more depends on the private consumption of capitalists than either model recognizes. Ultimately, most can be made of the ‘Fragment on Machines’ by reading it not as an exposure of capitalism’s internal contractions, but as a discussion of a possible communist future where labor (or work) will play but a minor role.

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Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

Current Molecular Pharmacology ◽

10.2174/1874467212666190620143303 ◽

2019 ◽

Vol 12 (4) ◽

pp. 311-323 ◽

Cited By ~ 3

Author(s):

Salvatore Benvenga ◽

Antonio Micali ◽

Giovanni Pallio ◽

Roberto Vita ◽

Consuelo Malta ◽

...

Keyword(s):

Structural Changes ◽

Natural Antioxidants ◽

Minor Role ◽

Positive Role ◽

Testosterone Levels ◽

Tnf Α ◽

Testicular Lesions ◽

A Minor ◽

Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

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