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DNA Repair Sep 2009The DNA damage and replication checkpoints are believed to primarily slow the progression of the cell cycle to allow DNA repair to occur. Here we summarize known aspects... (Review)
Review
The DNA damage and replication checkpoints are believed to primarily slow the progression of the cell cycle to allow DNA repair to occur. Here we summarize known aspects of the Saccharomyces cerevisiae checkpoints including how these responses are integrated into downstream effects on the cell cycle, chromatin, DNA repair, and cytoplasmic targets. Analysis of the transcriptional response demonstrates that it is far more complex and less relevant to the repair of DNA damage than the bacterial SOS response. We also address more speculative questions regarding potential roles of the checkpoint during the normal S-phase and how current evidence hints at a checkpoint activation mechanism mediated by positive feedback that amplifies initial damage signals above a minimum threshold.
Topics: Cell Cycle; DNA Damage; DNA Replication; Feedback, Physiological; Saccharomyces cerevisiae
PubMed: 19477695
DOI: 10.1016/j.dnarep.2009.04.021 -
FEMS Yeast Research Feb 2014The sirtuins are a phylogenetically conserved family of NAD(+) -dependent protein deacetylases that consume one molecule of NAD(+) for every deacetylated lysine side... (Review)
Review
The sirtuins are a phylogenetically conserved family of NAD(+) -dependent protein deacetylases that consume one molecule of NAD(+) for every deacetylated lysine side chain. Their requirement for NAD(+) potentially makes them prone to regulation by fluctuations in NAD(+) or biosynthesis intermediates, thus linking them to cellular metabolism. The Sir2 protein from Saccharomyces cerevisiae is the founding sirtuin family member and has been well characterized as a histone deacetylase that functions in transcriptional silencing of heterochromatin domains and as a pro-longevity factor for replicative life span (RLS), defined as the number of times a mother cell divides (buds) before senescing. Deleting SIR2 shortens RLS, while increased gene dosage causes extension. Furthermore, Sir2 has been implicated in mediating the beneficial effects of caloric restriction (CR) on life span, not only in yeast, but also in higher eukaryotes. While this paradigm has had its share of disagreements and debate, it has also helped rapidly drive the aging research field forward. S. cerevisiae has four additional sirtuins, Hst1, Hst2, Hst3, and Hst4. This review discusses the function of Sir2 and the Hst homologs in replicative aging and chronological aging, and also addresses how the sirtuins are regulated in response to environmental stresses such as CR.
Topics: Gene Expression Regulation, Fungal; Models, Biological; Saccharomyces cerevisiae; Sirtuins
PubMed: 24164855
DOI: 10.1111/1567-1364.12115 -
Seminars in Cell & Developmental Biology Sep 2010Macroautophagy (hereafter autophagy) is a cellular degradation process, which in yeast is induced in response to nutrient deprivation. In this process, a double-membrane... (Review)
Review
Macroautophagy (hereafter autophagy) is a cellular degradation process, which in yeast is induced in response to nutrient deprivation. In this process, a double-membrane vesicle, an autophagosome, surrounds part of the cytoplasm and fuses with the vacuole to allow the breakdown and subsequent recycling of the cargo. In yeast, many autophagy-related (ATG) genes have been identified that are required for selective and/or nonselective autophagy. In all autophagy-related pathways, core Atg proteins are required for the formation of the autophagosome, which is one of the most unique aspects of autophagy and is unlike other vesicle transport events. In contrast to nonselective autophagy, the selective processes are induced in response to various specific physiological conditions such as alterations in the carbon source. In this review, we provide an overview of the common aspects concerning the mechanism of autophagy-related pathways, and highlight recent advances in our understanding of the machinery that controls autophagy induction in response to nutrient starvation conditions.
Topics: Autophagy; Phagosomes; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Signal Transduction
PubMed: 20359542
DOI: 10.1016/j.semcdb.2010.03.009 -
The Journal of Cell Biology Nov 1977The budding yeast, Saccharomyces cerevisiae, was grown exponentially at different rates in the presence of growth rate-limiting concentrations of a protein synthesis...
The budding yeast, Saccharomyces cerevisiae, was grown exponentially at different rates in the presence of growth rate-limiting concentrations of a protein synthesis inhibitor, cycloheximide. The volumes of the parent cell and the bud were determined as were the intervals of the cell cycle devoted to the unbudded and budded periods. We found that S. cerevisiae cells divide unequally. The daughter cell (the cell produced at division by the bud of the previous cycle) is smaller and has a longer subsequent cell cycle than the parent cell which produced it. During the budded period most of the volume increase occurs in the bud and very little in the parent cell, while during the unbudded period both the daughter and the parent cell increase significantly in volume. The length of the budded interval of the cell cycle varies little as a function of population doubling time; the unbudded interval of the parent cell varies moderately; and the unbudded interval for the daughter cell varies greatly (in the latter case an increase of 100 min in population doubling time results in an increase of 124 min in the daughter cell's unbudded interval). All of the increase in the unbudded period occurs in that interval of G1 that precedes the point of cell cycle arrest by the S. cerevisiae alpha-mating factor. These results are qualitatively consistent with and support the model for the coordination of growth and division (Johnston, G. C., J. R. Pringle, and L. H. Hartwell. 1977. Exp. Cell. Res. 105:79-98.) This model states that growth and not the events of the DNA division cycle are rate limiting for cellular proliferation and that the attainment of a critical cell size is a necessary prerequisite for the "start" event in the DNA-division cycle, the event that requires the cdc 28 gene product, is inhibited by mating factor and results in duplication of the spindle pole body.
Topics: Cell Division; Cycloheximide; Models, Biological; Saccharomyces cerevisiae
PubMed: 400873
DOI: 10.1083/jcb.75.2.422 -
Brazilian Journal of Microbiology :... Dec 2013Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are...
Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Characterisation tests for invasiveness in Agar medium, killer activity, flocculation and fermentative capacity were performed on 22 strains (11 rough and 11 smooth colonies). The effects of acid treatment at different pH values on the growth of two strains ("52"--rough and "PE-02"--smooth) as well as batch fermentation tests with cell recycling and acid treatment of the cells were also evaluated. Invasiveness in YPD Agar medium occurred at low frequency; ten of eleven rough yeasts exhibited flocculation; none of the strains showed killer activity; and the rough strains presented lower and slower fermentative capacities compared to the smooth strains in a 48-h cycle in a batch system with sugar cane juice. The growth of the rough strain was severely affected by the acid treatment at pH values of 1.0 and 1.5; however, the growth of the smooth strain was not affected. The fermentative efficiency in mixed fermentation (smooth and rough strains in the same cell mass proportion) did not differ from the efficiency obtained with the smooth strain alone, most likely because the acid treatment was conducted at pH 1.5 in a batch cell-recycle test. A fermentative efficiency as low as 60% was observed with the rough colony alone.
Topics: Alcohols; Carboxylic Acids; Culture Media; Fermentation; Hydrogen-Ion Concentration; Saccharomyces cerevisiae
PubMed: 24688501
DOI: 10.1590/S1517-83822014005000020 -
FEMS Microbiology Reviews Mar 2014Homologous recombination (HR) contributes to maintaining genome integrity by facilitating error-free repair of DNA double-strand breaks (DSBs) primarily during the S and... (Review)
Review
Homologous recombination (HR) contributes to maintaining genome integrity by facilitating error-free repair of DNA double-strand breaks (DSBs) primarily during the S and G2 phases of the mitotic cell cycle, while nonhomologous end joining (NHEJ) is the preferred pathway for DSB repair in G1 phase. The decision to repair a DSB by NHEJ or HR is made primarily at the level of DSB end resection, which is inhibited by the Ku complex in G1 and promoted by the Sae2 and Mre11 nucleases in S/G2 . The cell cycle regulation of HR is accomplished both at the transcription level and at the protein level through post-translational modification, degradation and subcellular localization. Cyclin-dependent kinase Cdc28 plays an established key role in these events, while the role of transcriptional regulation and protein degradation are less well understood. Here, the cell cycle regulatory mechanisms for mitotic HR in Saccharomyces cerevisiae are reviewed, and evolutionarily conserved principles are highlighted.
Topics: Cell Cycle; DNA Breaks, Double-Stranded; DNA Repair; Homologous Recombination; Saccharomyces cerevisiae
PubMed: 24483249
DOI: 10.1111/1574-6976.12066 -
Genetics Nov 2011In response to nitrogen starvation in the presence of a poor carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and package the haploid... (Review)
Review
In response to nitrogen starvation in the presence of a poor carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and package the haploid nuclei produced in meiosis into spores. The formation of spores requires an unusual cell division event in which daughter cells are formed within the cytoplasm of the mother cell. This process involves the de novo generation of two different cellular structures: novel membrane compartments within the cell cytoplasm that give rise to the spore plasma membrane and an extensive spore wall that protects the spore from environmental insults. This article summarizes what is known about the molecular mechanisms controlling spore assembly with particular attention to how constitutive cellular functions are modified to create novel behaviors during this developmental process. Key regulatory points on the sporulation pathway are also discussed as well as the possible role of sporulation in the natural ecology of S. cerevisiae.
Topics: Animals; Cell Cycle; Cell Membrane; RNA Processing, Post-Transcriptional; Saccharomyces cerevisiae; Spores, Fungal
PubMed: 22084423
DOI: 10.1534/genetics.111.127126 -
International Microbiology : the... Jun 2002Killer yeasts secrete proteinaceous killer toxins lethal to susceptible yeast strains. These toxins have no activity against microorganisms other than yeasts, and the... (Review)
Review
Killer yeasts secrete proteinaceous killer toxins lethal to susceptible yeast strains. These toxins have no activity against microorganisms other than yeasts, and the killer strains are insensitive to their own toxins. Killer toxins differ between species or strains, showing diverse characteristics in terms of structural genes, molecular size, mature structure and immunity. The mechanisms of recognizing and killing sensitive cells differ for each toxin. Killer yeasts and their toxins have many potential applications in environmental, medical and industrial biotechnology. They are also suitable to study the mechanisms of protein processing and secretion, and toxin interaction with sensitive cells. This review focuses on the biological diversity of the killer toxins described up to now and their potential biotechnological applications.
Topics: Fermentation; Fungi; Killer Factors, Yeast; Mycotoxins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 12180782
DOI: 10.1007/s10123-002-0066-z -
Biochimica Et Biophysica Acta Aug 2007Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) elicit many of the responses that are evoked in cells by changes in certain... (Review)
Review
Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) elicit many of the responses that are evoked in cells by changes in certain environmental conditions and upon exposure to a variety of hormonal and other stimuli. These pathways were first elucidated in the unicellular eukaryote Saccharomyces cerevisiae (budding yeast). Studies of MAPK pathways in this organism continue to be especially informative in revealing the molecular mechanisms by which MAPK cascades operate, propagate signals, modulate cellular processes, and are controlled by regulatory factors both internal to and external to the pathways. Here we highlight recent advances and new insights about MAPK-based signaling that have been made through studies in yeast, which provide lessons directly applicable to, and that enhance our understanding of, MAPK-mediated signaling in mammalian cells.
Topics: Cell Cycle; Enzyme Activation; MAP Kinase Signaling System; Models, Biological; Protein Biosynthesis; Saccharomyces cerevisiae; Transcription, Genetic
PubMed: 17604854
DOI: 10.1016/j.bbamcr.2007.05.003 -
International Journal of Molecular... Mar 2018The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast . These key metabolites are... (Review)
Review
The concentrations of some key metabolic intermediates play essential roles in regulating the longevity of the chronologically aging yeast . These key metabolites are detected by certain ligand-specific protein sensors that respond to concentration changes of the key metabolites by altering the efficiencies of longevity-defining cellular processes. The concentrations of the key metabolites that affect yeast chronological aging are controlled spatially and temporally. Here, we analyze mechanisms through which the spatiotemporal dynamics of changes in the concentrations of the key metabolites influence yeast chronological lifespan. Our analysis indicates that a distinct set of metabolites can act as second messengers that define the pace of yeast chronological aging. Molecules that can operate both as intermediates of yeast metabolism and as second messengers of yeast chronological aging include reduced nicotinamide adenine dinucleotide phosphate (NADPH), glycerol, trehalose, hydrogen peroxide, amino acids, sphingolipids, spermidine, hydrogen sulfide, acetic acid, ethanol, free fatty acids, and diacylglycerol. We discuss several properties that these second messengers of yeast chronological aging have in common with second messengers of signal transduction. We outline how these second messengers of yeast chronological aging elicit changes in cell functionality and viability in response to changes in the nutrient, energy, stress, and proliferation status of the cell.
Topics: Cell Cycle; Saccharomyces cerevisiae; Second Messenger Systems
PubMed: 29543708
DOI: 10.3390/ijms19030860