The Sparing Effect of UV- and X-ray-dose-fractionation in Starved Diploid Yeast

1971 ◽  
Vol 26 (2) ◽  
pp. 129-133 ◽  
Author(s):  
Jürgen Kiefer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nutrient Medium ◽  
Complete Recovery ◽  
Dose Fractionation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Partial Synchronization ◽  
X Ray ◽  
Cell Progression ◽  
Sparing Effect

The sparing effect of UV- and X-ray dose fractionation and the influence of pre-exposure starvation were investigated in diploid yeast, Saccharomyces cerevisiae. A sparing effect could be demonstrated in starved cells if they were incubated in fresh nutrient medium during the fractionation interval. The time necessary for complete recovery, however, was greatly increased as compared to unstarved stationary phase cells. The possible role of cell progression and partial synchronization is discussed.

scholarly journals Coupling DNA Replication and Spindle Function in Saccharomyces cerevisiae

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3359
Author(s):  
Dimitris Liakopoulos
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Molecular Mechanisms ◽  
Genome Duplication ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spindle Dynamics ◽  
Eukaryotic Organisms ◽  
Spindle Function

In the yeast Saccharomyces cerevisiae DNA replication and spindle assembly can overlap. Therefore, signaling mechanisms modulate spindle dynamics in order to ensure correct timing of chromosome segregation relative to genome duplication, especially when replication is incomplete or the DNA becomes damaged. This review focuses on the molecular mechanisms that coordinate DNA replication and spindle dynamics, as well as on the role of spindle-dependent forces in DNA repair. Understanding the coupling between genome duplication and spindle function in yeast cells can provide important insights into similar processes operating in other eukaryotic organisms, including humans.

Lipid Rafts in Protein Sorting and Cell Polarity in Budding Yeast Saccharomyces cerevisiae

2002 ◽  
Vol 383 (10) ◽  
pp. 1475-1480 ◽  
Author(s):  
M. Bagnat ◽  
K. Simons
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Lipid Rafts ◽  
Cell Polarity ◽  
Budding Yeast ◽  
Protein Sorting ◽  
Yeast Saccharomyces Cerevisiae ◽  
Functional Consequences ◽  
Acyl Chains

Abstract Cellular membranes contain many types and species of lipids. One of the most important functional consequences of this heterogeneity is the existence of microdomains within the plane of the membrane. Sphingolipid acyl chains have the ability of forming tightly packed platforms together with sterols. These platforms or lipid rafts constitute segregation and sorting devices into which proteins specifically associate. In budding yeast, Saccharomyces cerevisiae, lipid rafts serve as sorting platforms for proteins destined to the cell surface. The segregation capacity of rafts also provides the basis for the polarization of proteins at the cell surface during mating. Here we discuss some recent findings that stress the role of lipid rafts as key players in yeast protein sorting and cell polarity.

Multifaceted role of the Saccharomyces cerevisiae Srs2 helicase in homologous recombination regulation

2005 ◽  
Vol 33 (6) ◽  
pp. 1447-1450 ◽  
Author(s):  
M.A. Macris ◽  
P. Sung
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Dna Replication ◽  
Homologous Recombination ◽  
High Energy ◽  
Yeast Saccharomyces Cerevisiae ◽  
Major Pathway ◽  
Dna Dsbs ◽  
Srs2 Helicase

Homologous recombination (HR) is a major pathway for the elimination of DNA DSBs (double-strand breaks) induced by high-energy radiation and chemicals, or that arise due to endogenous damage and stalled DNA replication forks. If not processed properly, DSBs can lead to cell death, chromosome aberrations and tumorigenesis. Even though HR is important for genome maintenance, it can also interfere with other DNA repair mechanisms and cause gross chromosome rearrangements. In addition, HR can generate DNA or nucleoprotein intermediates that elicit prolonged cell-cycle arrest and sometimes cell death. Genetic analyses in the yeast Saccharomyces cerevisiae have revealed a central role of the Srs2 helicase in preventing untimely HR events and in inhibiting the formation of potentially deleterious DNA structures or nucleoprotein complexes upon DNA replication stress. Paradoxically, efficient repair of DNA DSBs by HR is dependent on Srs2. In this paper, we review recent molecular studies aimed at deciphering the multifaceted role of Srs2 in HR and other cellular processes. These studies have provided critical insights into how HR is regulated in order to preserve genomic integrity and promote cell survival.

Uptake and trafficking of exogenous sterols in Saccharomyces cerevisiae

2006 ◽  
Vol 34 (3) ◽  
pp. 359-362 ◽  
Author(s):  
S. Raychaudhuri ◽  
W.A. Prinz
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Abc Transporters ◽  
Cellular Functions ◽  
Yeast Saccharomyces Cerevisiae ◽  
Membrane Function ◽  
Oxysterol Binding Protein ◽  
Atp Binding Cassette Transporters ◽  
Related Proteins

The proper distribution of sterols among organelles is critical for numerous cellular functions. How sterols are sorted and moved among membranes remains poorly understood, but they are transported not only in vesicles but also by non-vesicular pathways. One of these pathways moves exogenous sterols from the plasma membrane to the endoplasmic reticulum in the yeast Saccharomyces cerevisiae. We have found that two classes of proteins play critical roles in this transport, ABC transporters (ATP-binding-cassette transporters) and oxysterol-binding protein-related proteins. Transport is also regulated by phosphoinositides and the interactions of sterols with other lipids. Here, we summarize these findings and speculate on the role of non-vesicular sterol transfer in determining intracellular sterol distribution and membrane function.

The role of PSO and SNM genes in DNA repair of the yeast Saccharomyces cerevisiae

1990 ◽  
Vol 18 (5) ◽  
pp. 387-393 ◽  
Author(s):  
Jo�o A. P. Henriques ◽  
Martin Brendel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Yeast Saccharomyces Cerevisiae

scholarly journals Phosphatase 2A Negatively Regulates Mitotic Exit in Saccharomyces cerevisiae

2006 ◽  
Vol 17 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Yanchang Wang ◽  
Tuen-Yung Ng
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Exit ◽  
Regulatory Subunit ◽  
Temperature Sensitive ◽  
Cyclin Dependent Kinase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Catalytic Subunits ◽  
Phosphatase 2A ◽  
Negative Role

In budding yeast Saccharomyces cerevisiae, Cdc5 kinase is a component of mitotic exit network (MEN), which inactivates cyclin-dependent kinase (CDK) after chromosome segregation. cdc5-1 mutants arrest at telophase at the nonpermissive temperature due to the failure of CDK inactivation. To identify more negative regulators of MEN, we carried out a genetic screen for genes that are toxic to cdc5-1 mutants when overexpressed. Genes that encode the B-regulatory subunit (Cdc55) and the three catalytic subunits (Pph21, Pph22, and Pph3) of phosphatase 2A (PP2A) were isolated. In addition to cdc5-1, overexpression of CDC55, PPH21, or PPH22 is also toxic to other temperature-sensitive mutants that display defects in mitotic exit. Consistently, deletion of CDC55 partially suppresses the temperature sensitivity of these mutants. Moreover, in the presence of spindle damage, PP2A mutants display nuclear localized Cdc14, the key player in MEN pathway, indicative of MEN activation. All the evidence suggests the negative role of PP2A in mitotic exit. Finally, our genetic and biochemical data suggest that PP2A regulates the phosphorylation of Tem1, which acts at the very top of MEN pathway.

scholarly journals Differential mismatch repair can explain the disproportionalities between physical distances and recombination frequencies of cyc1 mutations in yeast.

Genetics ◽  
1988 ◽  
Vol 119 (1) ◽  
pp. 21-34
Author(s):  
C W Moore ◽  
D M Hampsey ◽  
J F Ernst ◽  
F Sherman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mismatch Repair ◽  
Meiotic Recombination ◽  
Mitotic Recombination ◽  
The Other ◽  
Recombination Rates ◽  
Base Pairs ◽  
Yeast Saccharomyces Cerevisiae ◽  
X Ray ◽  
Mismatched Base Pair

Abstract Recombination rates have been examined in two-point crosses of various defined cyc1 mutations that cause the loss or nonfunction of iso-1-cytochrome c in the yeast Saccharomyces cerevisiae. Recombinants arising by three different means were investigated, including X-ray induced mitotic recombination, spontaneous mitotic recombination, and meiotic recombination. Heteroallelic diploid strains were derived by crossing cyc1 mutants containing a series of alterations at or near the same site to cyc1 mutants containing alterations at various distances. Marked disproportionalities between physical distances and recombination frequencies were observed with certain cyc1 mutations, indicating that certain mismatched bases can significantly affect recombination. The marker effects were more pronounced when the two mutational sites of the heteroalleles were within about 20 base pairs, but separated by at least 4 base pairs. Two alleles, cyc1-163 and cyc1-166, which arose by G.C----C.G transversions at nucleotide positions 3 and 194, respectively, gave rise to especially high rates of recombination. Other mutations having different substitutions at the same nucleotide positions were not associated with abnormally high recombination frequencies. We suggest that these marker effects are due to the lack of repair of either G/G or C/C mismatched base pairs, while the other mismatched base pair of the heteroallele undergoes substantial repair. Furthermore, we suggest that diminished recombination frequencies are due to the concomitant repair of both mismatches within the same DNA tract.

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