scholarly journals Study of Cellular Processes in Higher Eukaryotes Using the Yeast Schizosaccharomyces pombe as a Model

10.5772/60720 ◽  
2015 ◽  
Author(s):  
Nora Hilda Rosas-Murrieta ◽  
Guadalupe Rojas-Sánchez ◽  
Sandra R. Reyes-Carmona ◽  
Rebeca D. Martínez-Contreras ◽  
Nancy Martínez-Montiel ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Cellular Processes ◽  
Higher Eukaryotes

scholarly journals Mycoplasmas and Their Antibiotic Resistance: The Problems and Prospects in Controlling Infections

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 24-34 ◽  
Author(s):  
O. A. Chernova ◽  
E. S. Medvedeva ◽  
A. A. Mouzykantov ◽  
N. B. Baranova ◽  
V. M. Chernov
Keyword(s):  
Antibiotic Resistance ◽  
Molecular Basis ◽  
Rapid Development ◽  
Integrated Approach ◽  
Stress Factors ◽  
Antimicrobial Drugs ◽  
Cellular Processes ◽  
Complex Processes ◽  
Development Of Resistance ◽  
Higher Eukaryotes

The present review discusses the problem of controlling mycoplasmas (class Mollicutes), the smallest of self-replicating prokaryotes, parasites of higher eukaryotes, and main contaminants of cell cultures and vaccines. Possible mechanisms for the rapid development of resistance to antimicrobial drugs in mycoplasmas have been analyzed. Omics technologies provide new opportunities for investigating the molecular basis of bacterial adaptation to stress factors and identifying resistomes, the total of all genes and their products contributing to antibiotic resistance in microbes. The data obtained using an integrated approach with post-genomics methods show that antibiotic resistance may be caused by more complex processes than has been believed heretofore. The development of antibiotic resistance in mycoplasmas is associated with essential changes in the genome, proteome, and secretome profiles, which involve many genes and proteins related to fundamental cellular processes and virulence.

scholarly journals Miga-mediated endoplasmic reticulum–mitochondria contact sites regulate neuronal homeostasis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Lingna Xu ◽  
Xi Wang ◽  
Jia Zhou ◽  
Yunyi Qiu ◽  
Weina Shang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Mitochondrial Dynamics ◽  
Molecular Organization ◽  
Lipid Transport ◽  
Cellular Processes ◽  
Contact Sites ◽  
Neuronal Homeostasis ◽  
Higher Eukaryotes ◽  
Lateral Sclerosis

Endoplasmic reticulum (ER)–mitochondria contact sites (ERMCSs) are crucial for multiple cellular processes such as calcium signaling, lipid transport, and mitochondrial dynamics. However, the molecular organization, functions, regulation of ERMCS, and the physiological roles of altered ERMCSs are not fully understood in higher eukaryotes. We found that Miga, a mitochondrion located protein, markedly increases ERMCSs and causes severe neurodegeneration upon overexpression in fly eyes. Miga interacts with an ER protein Vap33 through its FFAT-like motif and an amyotrophic lateral sclerosis (ALS) disease related Vap33 mutation considerably reduces its interaction with Miga. Multiple serine residues inside and near the Miga FFAT motif were phosphorylated, which is required for its interaction with Vap33 and Miga-mediated ERMCS formation. The interaction between Vap33 and Miga promoted further phosphorylation of upstream serine/threonine clusters, which fine-tuned Miga activity. Protein kinases CKI and CaMKII contribute to Miga hyperphosphorylation. MIGA2, encoded by the miga mammalian ortholog, has conserved functions in mammalian cells. We propose a model that shows Miga interacts with Vap33 to mediate ERMCSs and excessive ERMCSs lead to neurodegeneration.

Heat shock factor is required for growth at normal temperatures in the fission yeast Schizosaccharomyces pombe

1993 ◽  
Vol 13 (2) ◽  
pp. 749-761
Author(s):  
G J Gallo ◽  
H Prentice ◽  
R E Kingston
Keyword(s):  
Heat Shock ◽  
Schizosaccharomyces Pombe ◽  
Normal Growth ◽  
Growth Conditions ◽  
Heat Shock Factor ◽  
Binding Ability ◽  
Lower Growth ◽  
General Role ◽  
Functional Conservation ◽  
Cellular Processes

Schizosaccharomyces pombe is becoming an increasingly useful organism for the study of cellular processes, since in certain respects, such as the cell cycle and splicing, it is similar to metazoans. Previous biochemical studies have shown that the DNA binding ability of S. pombe heat shock factor (HSF) is fully induced only under stressed conditions, in a manner similar to that of Drosophila melanogaster and humans but differing from the constitutive binding by HSF in the budding yeasts. We report the isolation of the cDNA and gene for the HSF from S. pombe. S. pombe HSF has a domain structure that is more closely related to the structure of human and D. melanogaster HSFs than to the structure of the budding yeast HSFs, further arguing that regulation of HSF in S. pombe is likely to reflect regulation in metazoans. Surprisingly, the S. pombe HSF gene is required for growth at normal temperatures. We show that the S. pombe HSF gene can be replaced by the D. melanogaster HSF gene and that strains containing either of these genes behave similarly to transiently heat-shocked strains with respect to viability and the level of heat-induced transcripts from heat shock promoters. Strains containing the D. melanogaster HSF gene, however, have lower growth rates and show altered morphology at normal growth temperatures. These data demonstrate the functional conservation of domains of HSF that are required for response to heat shock. They further suggest a general role for HSF in growth of eukaryotic cells under normal (nonstressed) growth conditions.

Co-ordination of cytokinesis with chromosome segregation

2008 ◽  
Vol 36 (3) ◽  
pp. 387-390 ◽  
Author(s):  
Manuel Mendoza ◽  
Yves Barral
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Chromosome Segregation ◽  
Cleavage Plane ◽  
Budding Yeast ◽  
Sister Chromatids ◽  
Higher Eukaryotes ◽  
Spindle Elongation

During anaphase, the spindle pulls the sister kinetochores apart until the sister chromatids are fully separated from each other. Subsequently, cytokinesis cleaves between the two separated chromosome masses to form two nucleated cells. Results from Schizosaccharomyces pombe suggested that cytokinesis and chromosome segregation are not co-ordinated with each other. However, recent studies indicate that, at least in budding yeast, a checkpoint called NoCut prevents abscission when spindle elongation is impaired, and might delay cytokinesis until all chromosomes are pulled out of the cleavage plane. Here, we discuss this possibility and summarize evidence suggesting that such a checkpoint is likely to be conserved in higher eukaryotes.

scholarly journals Coordination of Initiation of Nuclear Division and Initiation of Cell Division in Schizosaccharomyces pombe: Genetic Interactions of Mutations

1998 ◽  
Vol 180 (4) ◽  
pp. 892-900 ◽  
Author(s):  
A. Grallert ◽  
B. Grallert ◽  
B. Ribar ◽  
M. Sipiczki
Keyword(s):  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
High Frequency ◽  
Mutant Allele ◽  
Nuclear Division ◽  
Genetic Interactions ◽  
Developmental Gene ◽  
M Phase ◽  
Regulatory Link ◽  
Higher Eukaryotes

ABSTRACT sep1+ encodes a Schizosaccharomyces pombe homolog of the HNF-3/forkhead family of the tissue-specific and developmental gene regulators identified in higher eukaryotes. Its mutant allele sep1-1 causes a defect in cytokinesis and confers a mycelial morphology. Here we report on genetic interactions of sep1-1 with the M-phase initiation mutationswee1− , cdc2-1w, andcdc25-22. The double mutants sep1-1 wee1− and sep1-1 cdc2-1w form dikaryon cells at high frequency, which is due to nuclear division in the absence of cell division. The dikaryosis is reversible and suppressible by cdc25-22. We propose that the geneswee1+ , cdc2+ ,cdc25+ , and sep1+ form a regulatory link between the initiation of mitosis and the initiation of cell division.

Yeast models for amyloid disease

2014 ◽  
Vol 56 ◽  
pp. 85-97 ◽  
Author(s):  
Barry Panaretou ◽  
Gary W. Jones
Keyword(s):  
Model Organism ◽  
Unicellular Eukaryote ◽  
Vast Array ◽  
Cellular Processes ◽  
High Profile ◽  
Genome Wide ◽  
Higher Eukaryotes ◽  
Multicellular Organisms ◽  
Amyloid Diseases ◽  
Broad Overview

Saccharomyces cerevisiae (baker's yeast) is a well-established eukaryotic model organism, which has significantly contributed to our understanding of mechanisms that drive numerous core cellular processes in higher eukaryotes. Moreover, this has led to a greater understanding of the underlying pathobiology associated with disease in humans. This tractable model offers an abundance of analytical capabilities, including a vast array of global genetics and molecular resources that allow genome-wide screening to be carried out relatively simply and cheaply. A prime example of the versatility and potential for applying yeast technologies to explore a mammalian disease is in the development of yeast models for amyloid diseases such as Alzheimer's, Parkinson's and Huntington's. The present chapter provides a broad overview of high profile human neurodegenerative diseases that have been modelled in yeast. We focus on some of the most recent findings that have been developed through genetic and drug screening studies using yeast genomic resources. Although this relatively simple unicellular eukaryote seems far removed from relatively complex multicellular organisms such as mammals, the conserved mechanisms for how amyloid exhibits toxicity clearly underscore the value of carrying out such studies in yeast.

scholarly journals Cell viability and secretion of active proteins in Schizosaccharomyces pombe do not require the chaperone function of calnexin

2004 ◽  
Vol 380 (2) ◽  
pp. 441-448 ◽  
Author(s):  
Alexandre MARÉCHAL ◽  
Pierre-Luc TANGUAY ◽  
Mario CALLEJO ◽  
Renée GUÉRIN ◽  
Guy BOILEAU ◽  
...  
Keyword(s):  
Quality Control ◽  
Schizosaccharomyces Pombe ◽  
Secretory Pathway ◽  
Cellular Processes ◽  
Rate Limiting Step ◽  
Secretion Efficiency ◽  
Model Protein ◽  
Endogenous Proteins ◽  
Quality Control Mechanism

Folding of newly synthesized proteins within the ER (endoplasmic reticulum) is a rate-limiting step in protein secretion. Thus ER molecular chaperones and foldases have a major impact in determining the rate and yield of these crucial cellular processes. Calnexin is a key ER chaperone implicated in the folding, retention and targeting for degradation of proteins that go through the secretory pathway. Calnexin molecules contain a highly conserved central domain (hcd) that has been proposed to be involved in the interaction with folding substrates and other chaperones. To gain a better understanding of the roles played by calnexin in the secretory pathway, we examined the efficiency of fission yeast (Schizosaccharomyces pombe) strains expressing calnexin mutants to secrete different model proteins. Remarkably, calnexin hcd-deletion mutants, although devoid of detectable chaperone activity in vitro, confer viability and cause a considerable increase in the secretion of heterologous cellulase. Surprisingly the quality-control efficiency, measured as the activity/amount ratio of secreted model protein, was not severely reduced in these calnexin hcd-deletion mutant strains. Our results indicate that the essential function of calnexin does not reside in its role in the folding or in the retention of misfolded proteins. These observations suggest the existence of a highly stringent quality control mechanism in the ER of S. pombe that might reduce the secretion efficiency of endogenous proteins.

scholarly journals Dual Functions for the Schizosaccharomyces pombe Inositol Kinase Ipk1 in Nuclear mRNA Export and Polarized Cell Growth

2008 ◽  
Vol 8 (2) ◽  
pp. 134-146 ◽  
Author(s):  
Bhaskarjyoti Sarmah ◽  
Susan R. Wente
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Cell Morphology ◽  
Mrna Export ◽  
Coiled Coil ◽  
Polarized Growth ◽  
Inositol Polyphosphate ◽  
Inositol Polyphosphates ◽  
Cellular Processes ◽  
Terminal Domain ◽  
Carboxy Terminal

ABSTRACT The inositol 1,3,4,5,6-pentakisphosphate (IP5) 2-kinase (Ipk1) catalyzes the production of inositol hexakisphosphate (IP6) in eukaryotic cells. Previous studies have shown that IP6 is required for efficient nuclear mRNA export in the budding yeast Saccharomyces cerevisiae. Here, we report the first functional analysis of ipk1 + in Schizosaccharomyces pombe. S. pombe Ipk1 (SpIpk1) is unique among Ipk1 orthologues in that it harbors a novel amino (N)-terminal domain with coiled-coil structural motifs similar to those of BAR (Bin-amphiphysin-Rvs) domain proteins. Mutants with ipk1 + deleted (ipk1Δ) had mRNA export defects as well as pleiotropic defects in polarized growth, cell morphology, endocytosis, and cell separation. The SpIpk1 catalytic carboxy-terminal domain was required to rescue these defects, and the mRNA export block was genetically linked to SpDbp5 function and, likely, IP6 production. However, the overexpression of the N-terminal domain alone also inhibited these functions in wild-type cells. This revealed a distinct noncatalytic function for the N-terminal domain. To test for connections with other inositol polyphosphates, we also analyzed whether the loss of asp1 + function, encoding an IP6 kinase downstream of Ipk1, had an effect on ipk1Δ cells. The asp1Δ mutant alone did not block mRNA export, and its cell morphology, polarized growth, and endocytosis defects were less severe than those of ipk1Δ cells. Moreover, ipk1Δ asp1Δ double mutants had altered inositol polyphosphate levels distinct from those of the ipk1Δ mutant. This suggested novel roles for asp1 + upstream of ipk1 +. We propose that IP6 production is a key signaling linchpin for regulating multiple essential cellular processes.

scholarly journals Schizosaccharomyces pombe Spk1 is a tyrosine-phosphorylated protein functionally related to Xenopus mitogen-activated protein kinase.

1993 ◽  
Vol 13 (10) ◽  
pp. 6427-6434 ◽  
Author(s):  
Y Gotoh ◽  
E Nishida ◽  
M Shimanuki ◽  
T Toda ◽  
Y Imai ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Tyrosine Phosphorylation ◽  
Mitogen Activated Protein Kinase ◽  
Diploid Strain ◽  
Evolutionarily Conserved ◽  
Mitogen Activated Protein ◽  
Tyrosine Phosphorylated Protein ◽  
Higher Eukaryotes ◽  
Direct Activator

Mitogen-activated protein kinase (MAPK) and its direct activator, MAPK kinase (MAPKK), have been suggested to play a pivotal role in a variety of signal transduction pathways in higher eukaryotes. The fission yeast Schizosaccharomyces pombe carries a gene, named spk1, whose product is structurally related to vertebrate MAPK. Here we show that Spk1 is functionally related to Xenopus MAPK. (i) Xenopus MAPK partially complemented a defect in the spk1- mutant. An spk1- diploid strain could not sporulate, but one carrying Xenopus MAPK could. (ii) Both Spk1 and Xenopus MAPK interfered with sporulation if overexpressed in S. pombe cells. (iii) Spk1 underwent tyrosine phosphorylation as does Xenopus MAPK. Tyrosine phosphorylation of Spk1 appeared to be dependent upon mating signals because it occurred in homothallic cells but not in heterothallic cells. Furthermore, this phosphorylation was diminished in a byr1 disruptant strain, suggesting that spk1 lies downstream of byr1, which encodes a MAPKK homolog in S. pombe. Taken together, the MAPKK-MAPK cascade may be evolutionarily conserved in signaling pathways in yeasts and vertebrates.

scholarly journals Characterization of a Holliday junction-resolving enzyme from Schizosaccharomyces pombe.

1997 ◽  
Vol 17 (11) ◽  
pp. 6465-6471 ◽  
Author(s):  
M F White ◽  
D M Lilley
Keyword(s):  
Homologous Recombination ◽  
Schizosaccharomyces Pombe ◽  
Holliday Junctions ◽  
Holliday Junction ◽  
Sequence Specificity ◽  
Common Pathway ◽  
Saccharomyces Cerevisiae Mitochondria ◽  
Higher Eukaryotes ◽  
High Degree

The rearrangement and repair of DNA by homologous recombination involves the creation of Holliday junctions, which are cleaved by a class of junction-specific endonucleases to generate recombinant duplex DNA products. Only two cellular junction-resolving enzymes have been identified to date: RuvC in eubacteria and CCE1 from Saccharomyces cerevisiae mitochondria. We have identified a protein from Schizosaccharomyces pombe which has 28% sequence identity to CCE1. The YDC2 protein has been cloned and overexpressed in Escherichia coli, and the purified recombinant protein has been shown to be a Holliday junction-resolving enzyme. YDC2 has a high degree of specificity for the structure of the four-way junction, to which it binds as a dimer. The enzyme exhibits a sequence specificity for junction cleavage that differs from both CCE1 and RuvC, and it cleaves fixed junctions at the point of strand exchange. The conservation of the mechanism of Holliday junction cleavage between two organisms as diverse as S. cerevisiae and S. pombe suggests that there may be a common pathway for mitochondrial homologous recombination in fungi, plants, protists, and possibly higher eukaryotes.

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