Nous remercions S. Robertson Jinks et E. Heidenreich pour fournir des plasmides et des souches de levure; P. Pham et MF Goodman pour aider les withthe TLS dosage. Ce travail a été soutenu en partie par la Fédération américaine pour la recherche sur le vieillissement de subvention et par le NIH AG20642, AG025135.

<ol>
	<li>Longo, V. D., Finch, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolutionary+medicine:+from+dwarf+model+systems+to+healthy+centenarians.">Evolutionary medicine: from dwarf model systems to healthy centenarians.</a> Science. 299, 1342-1346 (2003).</li><li>Fontana, L., Partridge, L., Longo, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extending+healthy+life+span--from+yeast+to+humans.">Extending healthy life span--from yeast to humans.</a> Science. 328, 321-326 (2010).</li><li>Mortimer, R. K., Johnston, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Life+span+of+individual+yeast+cells.">Life span of individual yeast cells.</a> Nature. 183, 1751-1752 (1959).</li><li>Muller, I., Zimmermann, M., Becker, D., Flomer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calendar+life+span+versus+budding+life+span+of+Saccharomyces+cerevisiae.">Calendar life span versus budding life span of Saccharomyces cerevisiae.</a> Mech. Ageing Dev. 12, 47-52 (1980).</li><li>Jazwinski, S. M., Egilmez, N. K., Chen, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Replication+control+and+cellular+life+span.">Replication control and cellular life span.</a> Exp. Gerontol. 24, 423-436 (1989).</li><li>Pohley, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+formal+mortality+analysis+for+populations+of+unicellular+organisms+(Saccharomyces+cerevisiae.">A formal mortality analysis for populations of unicellular organisms (Saccharomyces cerevisiae.</a> Mech Ageing Dev. 38, 231-243 (1987).</li><li>Longo, V. D., Gralla, E. B., Valentine, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superoxide+dismutase+activity+is+essential+for+stationary+phase+survival+in+Saccharomyces+cerevisiae.+Mitochondrial+production+of+toxic+oxygen+species+in+vivo.">Superoxide dismutase activity is essential for stationary phase survival in Saccharomyces cerevisiae. Mitochondrial production of toxic oxygen species in vivo.</a> J Biol Chem. 271, 12275-12280 (1996).</li><li>Longo, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The chronological life span of Saccharomyces cerevisiae. Studies of superoxide dismutase, Ras and Bcl-2 [dissertation]. , (1997).</li><li>Fabrizio, P., Pozza, F., Pletcher, S. D., Gendron, C. M., Longo, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+longevity+and+stress+resistance+by+Sch9+in+yeast.">Regulation of longevity and stress resistance by Sch9 in yeast.</a> Science. 292, 288-290 (2001).</li><li>Fabrizio, P., Longo, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chronological+life+span+of+Saccharomyces+cerevisiae.">The chronological life span of Saccharomyces cerevisiae.</a> Aging Cell. 2, 73-81 (2003).</li><li>Madia, F., Gattazzo, C., Fabrizio, P., Longo, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+model+system+for+age-dependent+DNA+damage+and+cancer.">A simple model system for age-dependent DNA damage and cancer.</a> Mech Ageing Dev. 128, 45-49 (2007).</li><li>Wei, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Life+span+extension+by+calorie+restriction+depends+on+Rim15+and+transcription+factors+downstream+of+Ras/PKA,+Tor,+and+Sch9.">Life span extension by calorie restriction depends on Rim15 and transcription factors downstream of Ras/PKA, Tor, and Sch9.</a> PLoS Genet. 4, e13-e13 (2008).</li><li>Fabrizio, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superoxide+is+a+mediator+of+an+altruistic+aging+program+in+Saccharomyces+cerevisiae.">Superoxide is a mediator of an altruistic aging program in Saccharomyces cerevisiae.</a> J Cell Biol. 166, 1055-1067 (2004).</li><li>Wei, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tor1/Sch9-regulated+carbon+source+substitution+is+as+effective+as+calorie+restriction+in+life+span+extension.">Tor1/Sch9-regulated carbon source substitution is as effective as calorie restriction in life span extension.</a> PLoS Genet. 5, e1000467-e1000467 (2009).</li><li>Capizzi, R. L., Jameson, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+table+for+the+estimation+of+the+spontaneous+mutation+rate+of+cells+in+culture.">A table for the estimation of the spontaneous mutation rate of cells in culture.</a> Mutat Res. 17, 147-148 (1973).</li><li>Heidenreich, E., Novotny, R., Kneidinger, B., Holzmann, V., Wintersberger, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-homologous+end+joining+as+an+important+mutagenic+process+in+cell+cycle-arrested+cells.">Non-homologous end joining as an important mutagenic process in cell cycle-arrested cells.</a> Embo J. 22, 2274-2283 (2003).</li><li>Heidenreich, E., Wintersberger, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Replication-dependent+and+selection-induced+mutations+in+respiration-competent+and+respiration-deficient+strains+of+Saccharomyces+cerevisiae.">Replication-dependent and selection-induced mutations in respiration-competent and respiration-deficient strains of Saccharomyces cerevisiae.</a> Mol Gen Genet. 260, 395-400 (1998).</li><li>Chen, C., Kolodner, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gross+chromosomal+rearrangements+in+Saccharomyces+cerevisiae+replication+and+recombination+defective+mutants.">Gross chromosomal rearrangements in Saccharomyces cerevisiae replication and recombination defective mutants.</a> Nat Genet. 23, 81-85 (1999).</li><li>Datta, A., Adjiri, A., New, L., Crouse, G. F., JinksRobertson, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitotic+crossovers+between+diverged+sequences+are+regulated+by+mismatch+repair+proteins+in+Saccaromyces+cerevisiae.">Mitotic crossovers between diverged sequences are regulated by mismatch repair proteins in Saccaromyces cerevisiae.</a> Mol Cell Biol. 16, 1085-1093 (1996).</li><li>Madia, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oncogene+homologue+Sch9+promotes+age-dependent+mutations+by+a+superoxide+and+Rev1/Polzeta-dependent+mechanism.">Oncogene homologue Sch9 promotes age-dependent mutations by a superoxide and Rev1/Polzeta-dependent mechanism.</a> J Cell Biol. 186, 509-523 (2009).</li><li>Wang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+expression+of+recombinant+genes+and+preparation+of+cell-free+extracts+in+yeast.">Controlled expression of recombinant genes and preparation of cell-free extracts in yeast.</a> Methods Mol Biol. 313, 317-331 (2006).</li><li>Fabrizio, P., Pletcher, S. D., Minois, N., Vaupel, J. W., Longo, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronological+aging-independent+replicative+life+span+regulation+by+Msn2/Msn4+and+Sod2+in+Saccharomyces+cerevisiae.">Chronological aging-independent replicative life span regulation by Msn2/Msn4 and Sod2 in Saccharomyces cerevisiae.</a> FEBS Lett. 557, 136-142 (2004).</li><li>Allen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+quiescent+and+nonquiescent+cells+from+yeast+stationary-phase+cultures.">Isolation of quiescent and nonquiescent cells from yeast stationary-phase cultures.</a> J Cell Biol. 174, 89-100 (2006).</li><li>Madia, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longevity+mutation+in+SCH9+prevents+recombination+errors+and+premature+genomic+instability+in+a+Werner/Bloom+model+system.">Longevity mutation in SCH9 prevents recombination errors and premature genomic instability in a Werner/Bloom model system.</a> J Cell Biol. 180, 67-81 (2008).</li></ol>

Aucun conflit d&#39;intérêt déclaré.

Liquid cultures du vieillissement présentent parfois une repousse / phénotype haletant 13, ce qui complique l&#39;analyse CLS. La repousse se produit généralement lorsque plus de 90-99% de la population a perdu sa viabilité. Ce phénotype est souvent associé au stress oxydatif accru et / ou de protection a diminué dans la cellule. Par exemple, la fréquence de ce phénotype fait plus que doubler dans les cellules dépourvues superoxyde dismutase cytosolique et réduit considérablement dans la longue durée de vie des mutants (par exemple, ou sch9 Δ Δ RAS2) ou des mutants surexprimant superoxyde dismutase 22. En pratique, nous définissons la repousse comme une augmentation de la viabilité ou la stabilisation de la viabilité pour les trois prélèvements consécutifs dans la phase de forte mortalité au cours du vieillissement chronologique. Fonction de l&#39;âge des fréquences des mutations d&#39;ADN varient grandement en fonction du contexte de contrainte, la manipulation génétique, les conditions de culture, ainsi que la repousse / haletant et de survie extrêmement faible. Pré-essais devraient être effectués à des moments tels que la survie moyenne et maximale avec une densité de placage de divers essais sur la mutation de déterminer gamme de fréquence de mutation avant d&#39;échelle d&#39;analyse performingthe durée de vie complet. La souche de type sauvage doit toujours être inclus dans une durée de vie ou étudier la fréquence de mutation en parallèle à tout traitement ou mutants génétiques, telles que les inter-expérience-variations peuvent être comptabilisées. Plusieurs répliques biologiques devraient être inclus dans l&#39;étude, et, à la fois liquide et in situ la viabilité / mutation essais devraient être effectués pour corroborer les résultats. Au lieu de se concentrer sur un type particulier de mutation de l&#39;ADN, profilage d&#39;une instabilité génomique dépendant de l&#39;âge en utilisant des dosages multiples en combinaison, peuvent faire la lumière sur les dommages d&#39;ADN spécifiques et de système de réparation de l&#39;ADN des dommages (s) qui contribuent à l&#39;instabilité génomique âge-dépendante. Par exemple, une augmentation significative de la brute réarrangements chromosomiques (RME), comparés à ceux des mutations de l&#39;ADN d&#39;autres, est observé dans la levure de type sauvage suggérant une pause brin elevationof double et / ou une déficience des non-homologue fin (NHEJ) au cours de la levure vieillissement chronologique (tableau 2). Le spectre de la mutation CAN1 (séquençage du gène CAN1) obtenu dans la levure de vieillissement de type sauvage a suggéré une augmentation des dommages oxydatifs au cours du vieillissement chronologique et d&#39;erreurs réparation de l&#39;ADN, tandis que, à long vécu mutants Δ sch9, dommages à l&#39;ADN moins oxydatif et beaucoup plus réduite synthèse trans erreurs ont été observées 20. Les méthodes décrites ici peuvent être encore dépensés pour étudier l&#39;instabilité génomique âge-dépendante. Par exemple, les cellules au repos et non de repos peut être isolé de la levure en phase stationnaire des cultures en utilisant la méthode du gradient de densité décrite par Allen et al. 23. Combiné avec le test de mutation décrit ici, nous avons signalé qu&#39;une grande partie de la fonction de l&#39;âge découle de mutations des cellules quiescentes, plutôt que les diviser, les cellules endommagées ou apoptotiques 20,24.

studying age-dependent genomic instability using the s. cerevisiae chronological lifespan model

Les études utilisant le modèle Saccharomyces cerevisiae vieillissement ont découvert des voies durée de vie de régulation qui sont partiellement conservés chez les eucaryotes supérieurs 1-2. La simplicité et la puissance du modèle de la levure de vieillissement peuvent aussi être explorées pour étudier les dommages de l&#39;ADN et la maintenance du génome ainsi que leurs contributions à des maladies au cours du vieillissement. Ici, nous décrivons un système à l&#39;étude des mutations d&#39;ADN dépendante de l&#39;âge, y compris des substitutions de base, cadre-déplacement des mutations, des réarrangements chromosomiques brute, et homologue / homéologues recombinaison, ainsi que l&#39;activité réparation de l&#39;ADN nucléaire, en combinant la durée de vie de la levure chronologique avec l&#39;ADN simples dommages et des essais de mutation. Les méthodes décrites ici devraient faciliter l&#39;identification des gènes / voies qui régulent l&#39;instabilité génomique et les mécanismes qui sous-tendent mutations de l&#39;ADN dépendante de l&#39;âge et le cancer chez les mammifères.

Watch this Scientific Journal Video about Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model at JoVE.com

Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model

Nous décrivons ici un ensemble d&#39;essais sur la mutation d&#39;ADN qui peuvent être combinés avec le modèle de la levure chronologique durée de vie à étudier les gènes / voies de régulation ou de contribuer à l&#39;instabilité ADN génomique au cours du vieillissement.

Etudier Instabilité génomique fonction de l&#39;âge en utilisant les S. cerevisiae Modèle chronologique Lifespan

Studies using the Saccharomyces cerevisiae aging model have uncovered life span regulatory pathways that are partially conserved in higher eukaryotes1-2. ...

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Biology

Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model

15.5K vues.  University of Southern California, Los Angeles. Nous décrivons ici un ensemble d'essais sur la mutation d'ADN qui peuvent être combinés avec le modèle de la levure chronologique durée de vie à étudier les gènes / voies de régulation ou de contribuer à l'instabilité ADN génomique au cours du vieillissement.

Vidéo: Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model

Assay for Adhesion and Agar Invasion in S. cerevisiae

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, biofilms can reduce industrial productivity, destroy structures, and threaten human life. 1-3 On the other hand, harnessing the power of biofilms can help clean the environment and generate sustainable energy. 4-8
The ability of S. cerevisiae to colonize surfaces and participate in complex biofilms was mostly ignored until the rediscovery of the differentiation programs triggered by various signaling pathways and environmental cues in this organism. 9, 10 The continuing interest in using S. cerevisiae as a model organism to understand the interaction and convergence of signaling pathways, such as the Ras-PKA, Kss1 MAPK, and Hog1 osmolarity pathways, quickly placed S. cerevisiae in the junction of biofilm biology and signal transduction research. 11-20 To this end, differentiation of yeast cells into long, adhesive, pseudohyphal filaments became a convenient readout for the activation of signal transduction pathways upon various environmental changes. However, filamentation is a complex collection of phenotypes, which makes assaying for it as if it were a simple phenotype misleading. In the past decade, several assays were successfully adopted from bacterial biofilm studies to yeast research, such as MAT formation assays to measure colony spread on soft agar and crystal violet staining to quantitatively measure cell-surface adherence. 12, 21 However, there has been some confusion in assays developed to qualitatively assess the adhesive and invasive phenotypes of yeast in agar.
Here, we present a simple and reliable method for assessing the adhesive and invasive quality of yeast strains with easy-to-understand steps to isolate the adhesion assessment from invasion assessment. Our method, adopted from previous studies, 10, 16 involves growing cells in liquid media and plating on differential nutrient conditions for growth of large spots, which we then wash with water to assess adhesion and rub cells completely off the agar surface to assess invasion into the agar. We eliminate the need for streaking cells onto agar, which affects the invasion of cells into the agar. In general, we observed that haploid strains that invade agar are always adhesive, yet not all adhesive strains can invade agar medium. Our approach can be used in conjunction with other assays to carefully dissect the differentiation steps and requirements of yeast signal transduction, differentiation, quorum sensing, and biofilm formation.

We describe a qualitative assay for yeast adhesion and agar invasion as a measure of invasive and pseudohyphal differentiation. This simple assay can be used to assess the invasive phenotype of various mutants as well as the effects environmental cues and signaling pathways on yeast differentiation.

Dosage de l&#39;adhésion et l&#39;invasion Agar chez S. cerevisiae

Yeasts are found in natural biofilms, where many microorganisms colonize surfaces. In artificial environments, such as surfaces of man-made objects, ...

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Biologie

A high-throughput method to globally study the organelle morphology in S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help achieve an comprehensive understanding of molecular pathways. In Saccharomyces cerevisiae, with the development of the non-essential gene deletion array, we can globally study the morphology of different organelles like the endoplasmic reticulum (ER) and the mitochondria using GFP (or variant)-markers in different gene backgrounds. However, incorporating GFP markers in each single mutant individually is a labor-intensive process. Here, we describe a procedure that is routinely used in our laboratory. By using a robotic system to handle high-density yeast arrays and drug selection techniques, we can significantly shorten the time required and improve reproducibility. In brief, we cross a GFP-tagged mitochondrial marker (Apc1-GFP) to a high-density array of 4,672 nonessential gene deletion mutants by robotic replica pinning.  Through diploid selection, sporulation, germination and dual marker selection, we recover both alleles. As a result, each haploid single mutant contains Apc1-GFP incorporated at its genomic locus. Now, we can study the morphology of mitochondria in all non-essential mutant background. Using this high-throughput approach, we can conveniently study and delineate the pathways and genes involved in the inheritance and the formation of organelles in a genome-wide setting.

GFP-fusion proteins are widely used to visualize organelles by confocal microscopy. However, screening for mutations that affect the morphology of organelles generally requires individual mutagenesis and is time consuming. Here, we demonstrate a method to simultaneously incorporate organelle-GFP markers in almost 5,000 non-essential genes in yeast.

Une méthode à haut débit pour étudier la morphologie globalement organite chez S. cerevisiae

High-throughput methods to examine protein localization or organelle morphology is an effective tool for studying protein interactions and can help ...

Identification of protein complexes with quantitative proteomics in S. cerevisiae

Lipids are the building blocks of cellular membranes that function as barriers and in compartmentalization of cellular processes, and recently, as important intracellular signalling molecules. However, unlike proteins, lipids are small hydrophobic molecules that traffic primarily by poorly described nonvesicular routes, which are hypothesized to occur at membrane contact sites (MCSs). MCSs are regions where the endoplasmic reticulum (ER) makes direct physical contact with a partnering organelle, e.g., plasma membrane (PM). The ER portion of ER-PM MCSs is enriched in lipid-synthesizing enzymes, suggesting that lipid synthesis is directed to these sites and implying that MCSs are important for lipid traffic. Yeast is an ideal model to study ER-PM MCSs because of their abundance, with over 1000 contacts per cell, and their conserved nature in all eukaryotes. Uncovering the proteins that constitute MCSs is critical to understanding how lipids traffic is accomplished in cells, and how they act as signaling molecules. We have found that an ER called Scs2p localize to ER-PM MCSs and is important for their formation. We are focused on uncovering the molecular partners of Scs2p. Identification of protein complexes traditionally relies on first resolving purified protein samples by gel electrophoresis, followed by in-gel digestion of protein bands and analysis of peptides by mass spectrometry. This often limits the study to a small subset of proteins. Also, protein complexes are exposed to denaturing or non-physiological conditions during the procedure. To circumvent these problems, we have implemented a large-scale quantitative proteomics technique to extract unbiased and quantified data. We use stable isotope labeling with amino acids in cell culture (SILAC) to incorporate staple isotope nuclei in proteins in an untagged control strain. Equal volumes of tagged culture and untagged, SILAC-labeled culture are mixed together and lysed by grinding in liquid nitrogen. We then carry out an affinity purification procedure to pull down protein complexes. Finally, we precipitate the protein sample, which is ready for analysis by high-performance liquid chromatography/ tandem mass spectrometry. Most importantly, proteins in the control strain are labeled by the heavy isotope and will produce a mass/ charge shift that can be quantified against the unlabeled proteins in the bait strain. Therefore, contaminants, or unspecific binding can be easily eliminated. By using this approach, we have identified several novel proteins that localize to ER-PM MCSs. Here we present a detailed description of our approach. 

Here we describe a new quantitative proteomics technique for identifying protein complexes in Saccharomyces cerevisiae. In this study, we have used the SILAC method together with affinity purification followed by tandem mass spectrometry to identify with high specificity the binding partners of an ER protein, Scs2p.

Identification des complexes protéiques avec la protéomique quantitative chez S. cerevisiae

Lipids are the building blocks of cellular membranes that function as barriers and in compartmentalization of cellular processes, and recently, as ...

Microarray Analysis for Saccharomyces cerevisiae

In this protocol, gene expression in yeast (Saccharomyces cerevisiae) is changed after exposure to oxidative stress induced by the addition of hydrogen peroxide (H2O2), an oxidizing agent. In the experiment, yeast is grown for 48 hours in 1/2X YPD broth containing 3X glucose. The culture is split into a control and treated group. The experiment culture is treated with 0.5 mM H2O2 in Hanks Buffered Saline (HBSS) for 1 hour. The control culture is treated with HBSS only. Total RNA is extracted from both cultures and is converted to a biotin-labeled cRNA product through a multistep process. The final synthesis product is taken back to the UVM Microarray Core Facility and hybridized to the Affymetrix yeast GeneChips. The resulting gene expression data are uploaded into bioinformatics data analysis software.

Microarray Analysis for Saccharomyces cerevisiae

In this protocol, gene expression in yeast (Saccharomyces cerevisiae) is changed after exposure to oxidative stress induced by the addition of hydrogen peroxide (H2O2), an oxidizing agent.

Analyse de Microarray pour Saccharomyces cerevisiae</em

In this protocol, gene expression in yeast (Saccharomyces cerevisiae) is changed after exposure to oxidative stress induced by the addition of hydrogen ...

Genomic MRI - a Public Resource for Studying Sequence Patterns within Genomic DNA

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in their nucleotide composition and consist of a complex mosaic of sequence patterns. These patterns include so-called Mid-Range Inhomogeneity (MRI) regions -- sequences 30-10000 nucleotides in length that are enriched by a particular base or combination of bases (e.g. (G+T)-rich, purine-rich, etc.). MRI regions are associated with unusual (non-B-form) DNA structures that are often involved in regulation of gene expression, recombination, and other genetic processes (Fedorova &amp; Fedorov 2010). The existence of a strong fixation bias within MRI regions against mutations that tend to reduce their sequence inhomogeneity additionally supports the functionality and importance of these genomic sequences (Prakash et al. 2009).
Here we demonstrate a freely available Internet resource -- the Genomic MRI program package -- designed for computational analysis of genomic sequences in order to find and characterize various MRI patterns within them (Bechtel et al. 2008). This package also allows generation of randomized sequences with various properties and level of correspondence to the natural input DNA sequences. The main goal of this resource is to facilitate examination of vast regions of non-coding DNA that are still scarcely investigated and await thorough exploration and recognition.

We present a public computational web site for the analysis of genomic sequences. It detects DNA sequence patterns with various non-random nucleotide compositions. This resource also generates randomized sequences with diverse levels of complexity.

Genomic IRM - une ressource publique pour l&#39;étude des schémas de séquence dans l&#39;ADN génomique

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in ...

Flow Cytometry-based Purification of S. cerevisiae Zygotes

Zygotes are essential intermediates between haploid and diploid states in the life cycle of many organisms, including yeast (Figure 1) 1. S. cerevisiae zygotes result from the fusion of haploid cells of distinct mating type (MATa, MATalpha) and give rise to corresponding stable diploids that successively generate as many as 20 diploid progeny as a result of their strikingly asymmetric mitotic divisions 2. Zygote formation is orchestrated by a complex sequence of events: In this process, soluble mating factors bind to cognate receptors, triggering receptor-mediated signaling cascades that facilitate interruption of the cell cycle and culminate in cell-cell fusion. Zygotes may be considered a model for progenitor or stem cell function.
Although much has been learned about the formation of zygotes and although zygotes have been used to investigate cell-molecular questions of general significance, almost all studies have made use of mating mixtures in which zygotes are intermixed with a majority population of haploid cells 3-8. Many aspects of the biochemistry of zygote formation and the continuing life of the zygote therefore remain uninvestigated.
Reports of purification of yeast zygotes describe protocols based on their sedimentation properties 9; however, this sedimentation-based procedure did not yield nearly 90% purity in our hands. Moreover, it has the disadvantage that cells are exposed to hypertonic sorbitol. We therefore have developed a versatile purification procedure. For this purpose, pairs of haploid cells expressing red or green fluorescent proteins were co-incubated to allow zygote formation, harvested at various times, and the resulting zygotes were purified using a flow cytometry-based sorting protocol. This technique provides a convenient visual assessment of purity and maturation. The average purity of the fraction is approximately 90%. According to the timing of harvest, zygotes of varying degrees of maturity can be recovered. The purified samples provide a convenient point of departure for "-omic" studies, for recovery of initial progeny, and for systematic investigation of this progenitor cell.

Flow Cytometry-based Purification of S. cerevisiae Zygotes

To purify zygotes of S. cerevisiae, haploid cells of opposite mating type were engineered to express red or green fluorescent proteins, co-incubated to allow zygote formation, and fractionated using a flow cytometry-based protocol. The highly-enriched fraction enables subsequent "-omic" studies, recovery of initial progeny, and systematic investigation of zygote morphogenesis.

Cytométrie en flux à base de purification de<em&gt; S. cerevisiae</em&gt; Zygotes

Zygotes are essential intermediates between haploid and diploid states in the life cycle of many organisms, including yeast (Figure 1) 1. S. cerevisiae ...

Evaluation of Zebrafish Kidney Function Using a Fluorescent Clearance Assay

The zebrafish embryo offers a tractable model to study organogenesis and model human genetic disease. Despite its relative simplicity, the zebrafish kidney develops and functions in almost the same way as humans. A major difference in the construction of the human kidney is the presence of millions of nephrons compared to the zebrafish that has only two. However, simplifying such a complex system into basic functional units has aided our understanding of how the kidney develops and operates. In zebrafish, the midline located glomerulus is responsible for the initial blood filtration into two pronephric tubules that diverge to run bilaterally down the embryonic axis before fusing to each other at the cloaca. The pronephric tubules are heavily populated by motile cilia that facilitate the movement of filtrate along the segmented tubule, allowing the exchange of various solutes before finally exiting via the cloaca2-4. Many genes responsible for CKD, including those related to ciliogenesis, have been studied in zebrafish5. However, a major draw back has been the difficulty in evaluating zebrafish kidney function after genetic manipulation. Traditional assays to measure kidney dysfunction in humans have proved non translational to zebrafish, mainly due to their aquatic environment and small size. For example, it is not physically possible to extract blood from embryonic staged fish for analysis of urea and creatinine content, as they are too small. In addition, zebrafish do not produce enough urine for testing on a simple proteinuria &#8216;dipstick&#8217;, which is often performed during initial patient examinations. We describe a fluorescent assay that utilizes the optical transparency of the zebrafish to quantitatively monitor the clearance of a fluorescent dye, over time, from the vasculature and out through the kidney, to give a read out of renal function1,6-9.

The zebrafish is a popular tool to model chronic kidney disease (CKD). However, their small size makes it impossible to evaluate renal function using traditional methods. We describe a fluorescent dye kidney clearance assay1 that allows quantitative analysis of zebrafish kidney function in CKD.

Évaluation de poisson zèbre fonction rénale utilisant une habilitation immunofluorescence

The zebrafish embryo offers a tractable model to study organogenesis and model human genetic disease. Despite its relative simplicity, the zebrafish ...

Using Microfluidic Devices to Measure Lifespan and Cellular Phenotypes in Single Budding Yeast Cells

Budding yeast Saccharomyces cerevisiae is an important model organism in aging research. Genetic studies have revealed many genes with conserved effects on the lifespan across species. However, the molecular causes of aging and death remain elusive. To gain a systematic understanding of the molecular mechanisms underlying yeast aging, we need high-throughput methods to measure lifespan and to quantify various cellular and molecular phenotypes in single cells. Previously, we developed microfluidic devices to track budding yeast mother cells throughout their lifespan while flushing away newborn daughter cells. This article presents a method for preparing microfluidic chips and for setting up microfluidic experiments. Multiple channels can be used to simultaneously track cells under different conditions or from different yeast strains. A typical setup can track hundreds of cells per channel and allow for high-resolution microscope imaging throughout the lifespan of the cells. Our method also allows detailed characterization of the lifespan, molecular markers, cell morphology, and the cell cycle dynamics of single cells. In addition, our microfluidic device is able to trap a significant amount of fresh mother cells that can be identified by downstream image analysis, making it possible to measure the lifespan with higher accuracy.

This article presents a protocol optimized for the production of microfluidic chips and the setup of microfluidic experiments to measure the lifespan and cellular phenotypes of single yeast cells.

L&#39;utilisation des dispositifs microfluidiques pour mesurer et cellulaire Lifespan dans Phenotypes simples cellules de levure de bourgeonnement

Budding yeast Saccharomyces cerevisiae is an important model organism in aging research. Genetic studies have revealed many genes with conserved effects ...

High-throughput Screening for Protein-based Inheritance in S. cerevisiae

The encoding of biological information that is accessible to future generations is generally achieved via changes to the DNA sequence. Long-lived inheritance encoded in protein conformation (rather than sequence) has long been viewed as paradigm-shifting but rare. The best characterized examples of such epigenetic elements are prions, which possess a self-assembling behavior that can drive the heritable manifestation of new phenotypes. Many archetypal prions display a striking N/Q-rich sequence bias and assemble into an amyloid fold. These unusual features have informed most screening efforts to identify new prion proteins. However, at least three known prions (including the founding prion, PrPSc) do not harbor these biochemical characteristics. We therefore developed an alternative method to probe the scope of protein-based inheritance based on a property of mass action: the transient overexpression of prion proteins increases the frequency at which they acquire a self-templating conformation. This paper describes a method for analyzing the capacity of the yeast ORFeome to elicit protein-based inheritance. Using this strategy, we previously found that &gt;1% of yeast proteins could fuel the emergence of biological traits that were long-lived, stable, and arose more frequently than genetic mutation. This approach can be employed in high throughput across entire ORFeomes or as a targeted screening paradigm for specific genetic networks or environmental stimuli. Just as forward genetic screens define numerous developmental and signaling pathways, these techniques provide a methodology to investigate the influence of protein-based inheritance in biological processes.

High-throughput Screening for Protein-based Inheritance in S. cerevisiae

This protocol describes a high-throughput methodology to functionally screen for protein-based inheritance in S. cerevisiae.

Criblage à haut débit pour l’héritage basées sur les protéines chez S. cerevisiae

The encoding of biological information that is accessible to future generations is generally achieved via changes to the DNA sequence. Long-lived ...

A Mouse Model of Lumbar Spine Instability

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L3&#8211;L5 spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L4&#8211;L5 IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L5) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

We developed a lumbar intervertebral disc degeneration mouse model by resection of L3&#8211;L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Un modèle de souris de l’instabilité lombaire de colonne vertébrale

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding ...