Vorremmo ringraziare il Dott. Rogers Ricco di assistenza tecnica con analisi di spettrometria di massa e utili discussioni, e Drs. Rob Moritz, Jeff Ranish, e Hamid Mirzai per utili discussioni. Questo lavoro è stato finanziato dal NIH Centri di Eccellenza.

La crescita delle cellule e dei media <ol><li> Una singola colonia di cellule BY4742Δarg4Δlys1 durante la notte in 100 ml di mezzi di comunicazione ricco di un OD 600 di 1,0 allora seme in due culture, 1 litro di un mezzo di lievito minimo (0,17% lievito di base di azoto, senza solfato di ammonio o amminoacidi, solfato di ammonio 0,5%) contenente un gamma completa di aminoacidi, integrata con 20 mg / L di arginina isotopi normale o pesante (13 C 6 15 N 4; Isotec) e lisina (13 C 6 15 N 2; Isotec). </li><li> Le cellule sono state coltivate per 18 ore, ad un OD 600 del 1.8. E &#39;fondamentale che le cellule passano attraverso almeno 9 generazioni per raggiungere piena integrazione dei isotopi etichettati. Il campione luce era pellet, lavato con acqua sterile, reseeded in un oleato contenente medio (isotopicamente normale arginina e lisina, 0,2% Oleato (chimici Sigma) e 0,5% di Tween 40 (Sigma Chimica)) e stimolati per altri 85 minuti. Questo produce un isotopicamente luce, per quanto riguarda l&#39;arginina e lisina, oleato stimolati campione e un isotopi pesanti di glucosio-cresciuto campione di riferimento. </li></ol> Cellula Lysis, Isolamento e frazionamento dei peptidi <ol start="3"><li> Pesare bottiglia centrifuga. Raccolta di campioni mediante centrifugazione per 3 minuti. Rimuovere i supporti ed aspirare il liquido in eccesso. Pesare pellet e bottiglia (in genere di rendimento tra i 1-2 grammi) e poi congelare il flash in azoto liquido. Aggiungi un equivalente volume a peso pellet di tampone &#39;macinazione&#39; per i pellet congelato in azoto liquido (tampone fosfato isotonico (PBS, Gibco), 10% glicerolo, inibitori della proteasi (SigmaFAST compresse inibitore della proteasi, Sigma) e gli inibitori della fosfatasi HALT (Thermo Scientific )). </li><li> Congelare la nave macinazione in azoto liquido. Attendere che l&#39;azoto liquido cessa bollente. Trasferire il pellet alla nave di rettifica, con cuscinetti a sfera congelata. </li><li> Grind a 600 giri al minuto con un min 1 ciclo di 20 secondi con una inversione di direzione per 3 minuti. Ricongelare la nave macinazione in azoto liquido. Ripetere 4 volte per 15 minuti il ​​tempo totale di macinazione. </li><li> Raccogliere la grindate congelato in un luogo ghiaccio 50ml tubo Falcon asciutto. Conservare a -80 ° C fino al momento dell&#39;uso. </li><li> Ottenere una soluzione 10 ml di urea 8M, bicarbonato di ammonio 0,1 M, 0,1 M Tris pH 8.6. Aggiungere 3 volumi del buffer di urea al 1 ° volume del grindate congelati (per esempio 3mls del buffer di urea aggiunto a un grammo 1 pellet con 1 ml di tampone PBS). Immediatamente sonicare la miscela con un sonicatore punta della sonda (2 - 10 impulsi al secondo). Tenere la punta vicino al fondo della provetta per evitare formazione di schiuma nella soluzione. Il grindate dovrebbe immediatamente andare in soluzione. </li><li> Cancella il lisato per centrifugazione per 5 minuti a 4 ° C. </li><li> Trasferire il supernatante in tubi di fresco. </li><li> Fai una nuova aliquota di 0,5 M Tris [2-carbossietil] fosfina (TCEP). Aggiungi a campione a 1:100 per una concentrazione 5mM finale. Incubare a 37 ° C per 1 h. </li><li> Alchilazione di cisteine ​​ridotte. Lasciare raffreddare a temperatura ambiente. Fai una nuova aliquota di Iodoacetamide 1M. Tenere al buio (ci avvolgere il tubo in alluminio). Aggiungere a una concentrazione finale di 20 mm. Incubare al buio per 1 ora a temperatura ambiente. </li><li> Placare la Iodoacetamide con DTT 20 mM da uno stock 1M a temperatura ambiente per 1 h. </li><li> Quantificare la proteina con una Bradford standard o BCA test (non descritto). Prelevare un campione per l&#39;analisi di SDS PAGE seguito. </li><li> Per convalidare l&#39;incorporazione degli isotopi pesanti, usare 100 ml di lisato ridotto e alchilata. Diluire 1:4 con dH 2 O, ultrasuoni e aggiungere tripsina a 50:1 proteine ​​tripsina. Digest per un minimo di 4 ore, campione secco giù in una velocità di vac e poi desalt con colonne Ultramicrospin C18 (il gruppo Nest). <ol><li> Idrato colonna con 100 ml di Acetonitrile </li><li> Equilibrare con 200 microlitri TFA 0,1%. </li><li> Risospendere campione secco in 200 microlitri TFA 0,1%. Caricare sulla colonna. Centrifugare a ~ 200 xg o la velocità minima necessaria per il flusso attraverso la colonna. </li><li> Lavare due volte con 200 microlitri TFA 0,1%. </li><li> Eluire con due volte con 50 microlitri Acetonitrile 60%, 0,1% TFA. </li><li> Campione secco a una velocità di vac. </li><li> Campione Risospendere in 20 microlitri di acido formico 0,1%. Run 2 microlitri su uno spettrometro di massa. Controllare l&#39;incorporazione di arginina e lisina isotopi pesanti da uno spostamento 10 e 8 Dalton nelle rispettive m / z spettri. L&#39;incorporazione di ogni amminoacido deve essere tra 96 ​​- 98%. </li></ol></li><li> Mix importi equivalenti (mg di proteine) dei campioni isotopi pesanti e leggeri. </li><li> Diluire il campione 1:4 con 20% di metanolo. </li><li> Aggiungi tripsina a 1:200. Incubare per una notte a 37 ° C. </li><li> Controllare che la digestione è andato a compimento da SDS PAGE. Run 2 e 4 ml di campione predigestione e 8 unod 16 microlitri della tripsina posta digerire. Visualizzate dalla colorazione Coomassie che la digestione è completa. Se non è completa, sonicare il campione con un breve sonicatore punta della sonda e digerire di nuovo con tripsina. </li><li> Secco il campione giù in una velocità di vac. Quando aggiungete a secco 200 ml di filtrato dH 2 O e agitare fino a pellet va in soluzione. Campione secco giù in una velocità di vac. Risospendere di nuovo con dH 2 O. Campione secco di nuovo. </li><li> Risospendere il pellet in 0,1% Acido Trifluoracetic (TFA, Sigma). Verificare che il pH è di circa 3 con strisce pH. Se necessario acidificare con il 10% TFA. </li><li> Pellet qualsiasi precipitato. </li><li> Desalificare i campioni su un set-Pak Waters Vac 500 mg colonna C18. Non sovraccaricare queste colonne. L&#39;importo massimo è di 5 mg, ma è meglio caricare un po &#39;meno. Dividere il campione tra i più colonne, se necessario. <ol><li> Idratare la colonna con 5 ml di acetonitrile al 100%. Centrifugare a ~ 200 xg o la velocità minima necessaria per il flusso attraverso la colonna. </li><li> Equilibrare colonna con 5ml TFA 0,1%. Carico del campione. Raccogliere il flusso e caricare di nuovo. </li><li> Lavare con 5 ml di TFA 0,1%. Ripeti. </li><li> Eluire con 2 ml Acetonitrile 60%, 0,1% TFA. </li><li> Campione secco giù in una velocità di vac. </li></ol></li></ol> Frazionamento peptide e isolamento di fosfopeptidi <ol><li> Peptidi sono frazionati su una colonna HILIC. Usiamo un Tosoh TSK-Gel Amide-80 4,6 millimetri x 25 cm colonna analitica con una colonna di guardia. Prendete il vostro tempo con questo passaggio, eseguire la colonna per 2 ore a 90% A eseguire due gradienti vuoto prima di caricare il vostro campione. Il carico massimo su una colonna è pensato che questo formato da circa XX, di solito non caricare più di 5 mg per ciclo. </li><li> Solvente A - 98% ACN/0.1% TFA Solvente B - 2% ACN/0.1% TFA Carico nel 90% A oltre 20 &#39;, 90% A 85% A più di 5&#39;, 85% A 60% A più di 40 &#39;, 60% A 0% A più di 5&#39;, 0% A 90% su A 5 &#39;. </li><li> La portata è 1ml/min e le frazioni sono stati raccolti ad intervalli di 2 minuti dall&#39;inizio al 85% A 60% Un gradiente. </li><li> Combina frazioni di ridurre il numero di frazioni a 10. Frazioni aumentato probabilmente resa maggiore copertura del phosphoproteome. </li></ol> Arricchimento del fosfopeptidi <ol><li> Fosfopeptidi sono arricchiti con PHOS-Select Gel Affinità di ferro. Noi la nostra aliquota resina IMAC per evitare congelamento ripetuto scongelamento. Fai 50 ml di acido acetico 250 mm, Soluzione al 30% del carico ACN. Portare il pH a 2,7 con HCl. Risospendere pellet in 500 ml di soluzione di carico. Controllare il pH, regolare con HCl o NaOH, se necessario. </li><li> Prelavaggio 200 ml di perline IMAC in una colonna appropriata. Noi usiamo colonne di rotazione Molbiotec. Aggiungere 15 ml di una sospensione al 50% (gel per caricare soluzione) per ogni frazione, e incubare i campioni per 30 &#39;con il fine più di rotazione finale. Mantenere il flusso per l&#39;analisi. </li><li> Lavare i campioni 3 volte con soluzione di carico e una volta con 500 microlitri filtrata dH 2 O. </li><li> Peptidi eluire con 2 - 3 minuti con 400 ml di 50 mM Na 2 HPO 4 (pH 8,4) buffer. Trasferire in un flaconcino di vetro. </li><li> Acidificare a pH 3 con 5 microlitri di acido formico al 100%, il flash congelare in azoto liquido, e campione essiccato giù in una velocità di vac. </li><li> Fosfopeptidi risospendere in 200 ml di 0,1% TFA e C18 pulito come descritto sopra. Secco giù campioni eluiti in una velocità vac. </li><li> Risospendere peptidi in 20 microlitri di 0.1% di acido formico. Utilizzare 2 microlitri per analisi spettrometro di massa o, se necessario. </li></ol> Note Per gran parte di questo protocollo si dovrà lavorare &#39;cieco&#39;. La lisi cellulare può essere monitorato da western blotting e saggi di Bradford e BCA, e la digestione tripsina può anche essere facilmente valutata. La colonna HILIC si diede una traccia simile a questa, o come visibile da altri [1, 2] a seconda della macchina cromatografia liquida che viene utilizzata. I campioni sono monitorati mediante spettrometria di massa, i campioni di prova su macchine poco costose come LCQs o MALDIs prima di andare in analisi dei costi in alto su una massa ad alta precisione, macchine ad alta risoluzione. Infine, se si un&#39;asciugatura giù un campione con acido in essa, l&#39;uso di vetro.

<ol>
	<li>Albuquerque, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+multidimensional+chromatography+technology+for+in-depth+phosphoproteome+analysis.">A multidimensional chromatography technology for in-depth phosphoproteome analysis.</a> Mol Cell Proteomics. 7 (7), 1389-1396 (2008).</li><li>McNulty, D. E., Annan, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophilic+interaction+chromatography+reduces+the+complexity+of+the+phosphoproteome+and+improves+global+phosphopeptide+isolation+and+detection.">Hydrophilic interaction chromatography reduces the complexity of the phosphoproteome and improves global phosphopeptide isolation and detection.</a> Mol Cell Proteomics. 7 (5), 971-980 (2008).</li><li>Gygi, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+complex+protein+mixtures+using+isotope-coded+affinity+tags.">Quantitative analysis of complex protein mixtures using isotope-coded affinity tags.</a> Nat Biotechnol. 17 (10), 994-999 (1999).</li><li>Ross, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplexed+protein+quantitation+in+Saccharomyces+cerevisiae+using+amine-reactive+isobaric+tagging+reagents.">Multiplexed protein quantitation in Saccharomyces cerevisiae using amine-reactive isobaric tagging reagents.</a> Mol Cell Proteomics. 3 (12), 1154-1169 (2004).</li><li>Gruhler, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+phosphoproteomics+applied+to+the+yeast+pheromone+signaling+pathway.">Quantitative phosphoproteomics applied to the yeast pheromone signaling pathway.</a> Mol Cell Proteomics. 4 (3), 310-327 (2005).</li><li>Wilson-Grady, J. T., Villen, J., Gygi, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphoproteome+analysis+of+fission+yeast.">Phosphoproteome analysis of fission yeast.</a> J Proteome Res. 7 (3), 1088-1097 (2008).</li><li>Villen, J., Gygi, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+SCX/IMAC+enrichment+approach+for+global+phosphorylation+analysis+by+mass+spectrometry.">The SCX/IMAC enrichment approach for global phosphorylation analysis by mass spectrometry.</a> Nat Protoc. 3 (10), 1630-1638 (2008).</li><li>Jensen, S. S., Larsen, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+impact+of+some+experimental+procedures+on+different+phosphopeptide+enrichment+techniques.">Evaluation of the impact of some experimental procedures on different phosphopeptide enrichment techniques.</a> Rapid Commun Mass Spectrom. 21 (22), 3635-3645 (2007).</li><li>Larsen, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+selective+enrichment+of+phosphorylated+peptides+from+peptide+mixtures+using+titanium+dioxide+microcolumns.">Highly selective enrichment of phosphorylated peptides from peptide mixtures using titanium dioxide microcolumns.</a> Mol Cell Proteomics. 4 (7), 873-886 (2005).</li><li>Pinkse, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+isolation+at+the+femtomole+level+of+phosphopeptides+from+proteolytic+digests+using+2D-NanoLC-ESI-MS/MS+and+titanium+oxide+precolumns.">Selective isolation at the femtomole level of phosphopeptides from proteolytic digests using 2D-NanoLC-ESI-MS/MS and titanium oxide precolumns.</a> Anal Chem. 76 (14), 3935-3943 (2004).</li><li>Tao, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+phosphoproteome+analysis+using+a+dendrimer+conjugation+chemistry+and+tandem+mass+spectrometry.">Quantitative phosphoproteome analysis using a dendrimer conjugation chemistry and tandem mass spectrometry.</a> Nat Methods. 2 (8), 591-598 (2005).</li><li>Zhou, H., Watts, J. D., Aebersold, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+systematic+approach+to+the+analysis+of+protein+phosphorylation.">A systematic approach to the analysis of protein phosphorylation.</a> Nat Biotechnol. 19 (4), 375-378 (2001).</li><li>Bodenmiller, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducible+isolation+of+distinct,+overlapping+segments+of+the+phosphoproteome.">Reproducible isolation of distinct, overlapping segments of the phosphoproteome.</a> Nat Methods. 4 (3), 231-237 (2007).</li></ol>

Questo metodo produrrà un arricchimento di fosfopeptidi che può essere analizzato quantitativamente. Un certo numero di parametri possono essere modificati in questo protocollo, ma l&#39;aspetto più importante da ricordare è per preservare la vostra fosforilazione. Preparazione delle cellule per la quantificazione può essere ottenuto in molti modi diversi, ad esempio se non si possono etichettare le cellule in vivo, i tag come ICAT [3] o ITRAC [4] può essere utilizzato estrazione messaggio per etichettare...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Isotec&trade; L-Arginine-13C6,15N4</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>608033</td>
<td>&nbsp;</td>
<tr>
<td>Isotec&trade; L-Lysine-15N2</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>609021</td>
<td>&nbsp;</td>
<tr>
<td>GIBCO&#x2122; Phosphate-Buffered Saline (PBS) 7.4 (10X) liquid</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>70011044</td>
<td>&nbsp;</td>
<tr>
<td>SigmaFAST Protease Inhibitor Tablets</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>S8820</td>
<td>&nbsp;</td>
<tr>
<td>Pierce Halt Phosphatase Inhibitor Cocktail</td>
<td>&nbsp;</td>
<td>Thermo Scientific</td>
<td>78420</td>
<td>&nbsp;</td>
<tr>
<td>Retsch PM100 Ball Mill Grinder </td>
<td>&nbsp;</td>
<td>Retsch</td>
<td>20.540.0001</td>
<td>&nbsp;</td>
<tr>
<td>Retsch 125 ml Stainless Steel Grinding Jar</td>
<td>&nbsp;</td>
<td>Retsch</td>
<td>01.462.0148</td>
<td>&nbsp;</td>
<tr>
<td>Ultramicrospin C18 column</td>
<td>&nbsp;</td>
<td>The Nest Group</td>
<td>SUM SS10</td>
<td>&nbsp;</td>
<tr>
<td>Sep-Pak Vac 500 mg C18</td>
<td>&nbsp;</td>
<td>Waters</td>
<td>WAT043395</td>
<td>&nbsp;</td>
<tr>
<td>TSK-Gel Amide-80 4.6 mm x 25 cm analytical column</td>
<td>&nbsp;</td>
<td>TOSOH BioSciences</td>
<td>13071</td>
<td>This is the HILIC chromatographic column.</td>
</tr>
<tr>
<td>Guard column 4.6 mm ID x1 cm</td>
<td>&nbsp;</td>
<td>TOSOH BioSciences</td>
<td>19021</td>
<td>We recommend this guard column to extend the life of your HILIC column.</td>
</tr>
<tr>
<td>PHOS-Select&trade; Iron Affinity Gel</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>P9740</td>
<td>This is the IMAC resin. Aliquot and store.</td>
</tr>		</tbody>
		</table>
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quantitative phosphoproteomics in fatty acid stimulated saccharomyces cerevisiae

Questo protocollo descrive la crescita e la stimolazione, con l&#39;oleato di acidi grassi, degli isotopi pesanti e leggeri cellule di S. cerevisiae. Le cellule sono a terra con un procedimento cryolysis in una smerigliatrice mulino a sfere e la conseguente grindate portato in soluzione mediante solubilizzazione urea. Questa procedura permette la lisi delle cellule in uno stato metabolicamente inattivo, conservando la fosforilazione e la prevenzione riorientamento della phosphoproteome durante la lisi cellulare. Dopo la riduzione, alchilazione, tripsina digestione delle proteine, i campioni sono dissalati su colonne C18 e la complessità del campione ridotto di frazionamento mediante cromatografia di interazione idrofilica (HILIC). Colonne HILIC preferenzialmente trattenere le molecole idrofile che ben si adatta per fosfoproteomica. Peptidi fosforilata tendono ad eluire successivamente nel profilo cromatografico che le controparti non fosforilata. Dopo frazionamento, fosfopeptidi sono arricchite usando la cromatografia in metallo immobilizzato, che si basa sulla carica a base di affinità per l&#39;arricchimento fosfopeptide. Al termine di questa procedura i campioni sono pronti per essere analizzato quantitativamente mediante spettrometria di massa.

Watch this Scientific Journal Video about Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae at JoVE.com

Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae

Descrizione di una procedura di fosforilazione quantitativa, utilizzando cryolysis, solubilziation urea, frazionamento HILIC e arricchimento IMAC di peptidi fosforilati.

Fosfoproteomica quantitativa in acidi grassi Stimolati Saccharomyces cerevisiae</em

This protocol describes the growth and stimulation, with the fatty acid oleate, of isotopically heavy and light S. cerevisiae cells. Cells are ground ...

quantitative-phosphoproteomics-fatty-acid-stimulated-saccharomyces

Research

JoVE Journal

Biology

Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae

10.0K Views.  Institute for Systems Biology. Descrizione di una procedura di fosforilazione quantitativa, utilizzando cryolysis, solubilziation urea, frazionamento HILIC e arricchimento IMAC di peptidi fosforilati.

Video: Quantitative Phosphoproteomics in Fatty Acid Stimulated Saccharomyces cerevisiae

Dissection of Saccharomyces Cerevisiae Asci

Yeast is a highly tractable model system that is used to study many different cellular processes. The common laboratory strain Saccharomyces cerevisiae exists in either a haploid or diploid state. The ability to combine alleles from two haploids and the ability to introduce modifications to the genome requires the production and dissection of asci. Asci production from haploid cells begins with the mating of two yeast haploid strains with compatible mating types to produce a diploid strain. This can be accomplished in a number of ways either on solid medium or in liquid. It is advantageous to select for the diploids in medium that selectively promotes their growth compared to either of the haploid strains. The diploids are then allowed to sporulate on nutrient-poor medium to form asci, a bundle of four haploid daughter cells resulting from meiotic reproduction of the diploid. A mixture of vegetative cells and asci is then treated with the enzyme zymolyase to digest away the membrane sac surrounding the ascospores of the asci. Using micromanipulation with a microneedle under a dissection microscope one can pick up individual asci and separate and relocate the four ascopores. Dissected asci are grown for several days and tested for the markers or alleles of interest by replica plating onto appropriate selective media.

Dissection of Saccharomyces Cerevisiae Asci

Micromanipulation of yeast cells is needed for meiotic genetic analysis or to select diploid zygotes. These micromanipulations are carried out using the microneedle of a dissection microscope. The microneedle is used to relocate cells and is controlled by a micromanipulator which are available with various degrees of automation.

Dissezione di Saccharomyces cerevisiae Asci

Yeast is a highly tractable model system that is used to study many different cellular processes. The common laboratory strain Saccharomyces cerevisiae ...

Ricerca

Biologia

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.

Microarray analisi per 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 ...

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a quality control mechanism that can target and selectively degrade cellular material including organelles1-4. For example, damaged or redundant mitochondria (Fig. 1), not disposed of by autophagy, can represent a threat to cellular homeostasis and cell survival. In the yeast, Saccharomyces cerevisiae, nutrient deprivation (e.g., nitrogen starvation) or damage can promote selective turnover of mitochondria by autophagy in a process termed mitophagy 5-9.
We describe a simple fluorescence microscopy approach to assess autophagy. For clarity we restrict our description here to show how the approach can be used to monitor mitophagy in yeast cells. The assay makes use of a fluorescent reporter, Rosella, which is a dual-emission biosensor comprising a relatively pH-stable red fluorescent protein linked to a pH-sensitive green fluorescent protein. The operation of this reporter relies on differences in pH between the vacuole (pH ~ 5.0-5.5) and mitochondria (pH ~ 8.2) in living cells. Under growing conditions, wild type cells exhibit both red and green fluorescence distributed in a manner characteristic of the mitochondria. Fluorescence emission is not associated with the vacuole. When subjected to nitrogen starvation, a condition which induces mitophagy, in addition to red and green fluorescence labeling the mitochondria, cells exhibit the accumulation of red, but not green fluorescence, in the acidic vacuolar lumen representing the delivery of mitochondria to the vacuole. Scoring cells with red, but not green fluorescent vacuoles can be used as a measure of mitophagic activity in cells5,10-12.

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

A robust approach to monitor the delivery of organelles to the acidic lumen of the yeast vacuole for degradation and recycling is described. The method relies on the specific labeling of target organelles with a genetically encoded dual-emission fluorescence pH-biosensor, and visualization of individual cells using fluorescence microscopy.

Un saggio microscopia a fluorescenza per Mitophagy monitoraggio nel lievito Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a ...

Quantitation and Analysis of the Formation of HO-Endonuclease Stimulated Chromosomal Translocations by Single-Strand Annealing in Saccharomyces cerevisiae

Genetic variation is frequently mediated by genomic rearrangements that arise through interaction between dispersed repetitive elements present in every eukaryotic genome. This process is an important mechanism for generating diversity between and within organisms1-3. The human genome consists of approximately 40% repetitive sequence of retrotransposon origin, including a variety of LINEs and SINEs4. Exchange events between these repetitive elements can lead to genome rearrangements, including translocations, that can disrupt gene dosage and expression that can result in autoimmune and cardiovascular diseases5, as well as cancer in humans6-9.
Exchange between repetitive elements occurs in a variety of ways. Exchange between sequences that share perfect (or near-perfect) homology occurs by a process called homologous recombination (HR). By contrast, non-homologous end joining (NHEJ) uses little-or-no sequence homology for exchange10,11. The primary purpose of HR, in mitotic cells, is to repair double-strand breaks (DSBs) generated endogenously by aberrant DNA replication and oxidative lesions, or by exposure to ionizing radiation (IR), and other exogenous DNA damaging agents. 
In the assay described here, DSBs are simultaneously created bordering recombination substrates at two different chromosomal loci in diploid cells by a galactose-inducible HO-endonuclease (Figure 1). The repair of the broken chromosomes generates chromosomal translocations by single strand annealing (SSA), a process where homologous sequences adjacent to the chromosome ends are covalently joined subsequent to annealing. One of the substrates, his3-&Delta;3', contains a 3' truncated HIS3 allele and is located on one copy of chromosome XV at the native HIS3 locus. The second substrate, his3-&Delta;5', is located at the LEU2 locus on one copy of chromosome III, and contains a 5' truncated HIS3 allele. Both substrates are flanked by a HO endonuclease recognition site that can be targeted for incision by HO-endonuclease. HO endonuclease recognition sites native to the MAT locus, on both copies of chromosome III, have been deleted in all strains. This prevents interaction between the recombination substrates and other broken chromosome ends from interfering in the assay. The KAN-MX-marked galactose-inducible HO endonuclease expression cassette is inserted at the TRP1 locus on chromosome IV. The substrates share 311 bp or 60 bp of the HIS3 coding sequence that can be used by the HR machinery for repair by SSA. Cells that use these substrates to repair broken chromosomes by HR form an intact HIS3 allele and a tXV::III chromosomal translocation that can be selected for by the ability to grow on medium lacking histidine (Figure 2A). Translocation frequency by HR is calculated by dividing the number of histidine prototrophic colonies that arise on selective medium by the total number of viable cells that arise after plating appropriate dilutions onto non-selective medium (Figure 2B). A variety of DNA repair mutants have been used to study the genetic control of translocation formation by SSA using this system12-14.

Quantitation and Analysis of the Formation of HO-Endonuclease Stimulated Chromosomal Translocations by Single-Strand Annealing in Saccharomyces cerevisiae

The HO-stimulated translocation assay monitors single-strand annealing following the creation of DNA double-strand breaks at multiple loci in diploid Saccharomyces cerevisiae. This mechanism may model genome rearrangements in somatic cells of higher eukaryotes following exposure to high doses of ionizing radiation.

Quantificazione e analisi della formazione di HO-endonucleasi Stimolato traslocazioni cromosomiche da Single-Strand Ricottura in Saccharomyces cerevisiae</em

Genetic variation is frequently mediated by genomic rearrangements that arise through interaction between dispersed repetitive elements present in every ...

Visualization and Analysis of mRNA Molecules Using Fluorescence In Situ Hybridization in Saccharomyces cerevisiae

The Fluorescence in situ Hybridization (FISH) method allows one to detect nucleic acids in the native cellular environment. Here we provide a protocol for using FISH to quantify the number of mRNAs in single yeast cells. Cells can be grown in any condition of interest and then fixed and made permeable. Subsequently, multiple single-stranded deoxyoligonucleotides conjugated to fluorescent dyes are used to label and visualize mRNAs. Diffraction-limited fluorescence from single mRNA molecules is quantified using a spot-detection algorithm to identify and count the number of mRNAs per cell. While the more standard quantification methods of northern blots, RT-PCR and gene expression microarrays provide information on average mRNAs in the bulk population, FISH facilitates both the counting and localization of these mRNAs in single cells at single-molecule resolution.

Visualization and Analysis of mRNA Molecules Using Fluorescence In Situ Hybridization in Saccharomyces cerevisiae

This protocol describes an experimental procedure for performing Fluorescence in situ Hybridization (FISH) for counting mRNAs in single cells at single-molecule resolution.

Visualizzazione e l&#39;analisi di molecole di mRNA mediante fluorescenza<em&gt; In Situ</em&gt; Ibridazione in<em&gt; Saccharomyces cerevisiae</em

The Fluorescence in situ Hybridization (FISH) method allows one to detect nucleic acids in the native cellular environment. Here we provide a protocol for ...

Coupled Assays for Monitoring Protein Refolding in Saccharomyces cerevisiae

Proteostasis, defined as the combined processes of protein folding/biogenesis, refolding/repair, and degradation, is a delicate cellular balance that must be maintained to avoid deleterious consequences 1. External or internal factors that disrupt this balance can lead to protein aggregation, toxicity and cell death. In humans this is a major contributing factor to the symptoms associated with neurodegenerative disorders such as Huntington's, Parkinson's, and Alzheimer's diseases 10. It is therefore essential that the proteins involved in maintenance of proteostasis be identified in order to develop treatments for these debilitating diseases. This article describes techniques for monitoring in vivo protein folding at near-real time resolution using the model protein firefly luciferase fused to green fluorescent protein (FFL-GFP). FFL-GFP is a unique model chimeric protein as the FFL moiety is extremely sensitive to stress-induced misfolding and aggregation, which inactivates the enzyme 12. Luciferase activity is monitored using an enzymatic assay, and the GFP moiety provides a method of visualizing soluble or aggregated FFL using automated microscopy. These coupled methods incorporate two parallel and technically independent approaches to analyze both refolding and functional reactivation of an enzyme after stress. Activity recovery can be directly correlated with kinetics of disaggregation and re-solubilization to better understand how protein quality control factors such as protein chaperones collaborate to perform these functions. In addition, gene deletions or mutations can be used to test contributions of specific proteins or protein subunits to this process. In this article we examine the contributions of the protein disaggregase Hsp104 13, known to partner with the Hsp40/70/nucleotide exchange factor (NEF) refolding system 5, to protein refolding to validate this approach.

Coupled Assays for Monitoring Protein Refolding in Saccharomyces cerevisiae

This article describes the use of a firefly luciferase-GFP fusion protein to investigate in vivo protein folding in Saccharomyces cerevisiae. Using this reagent, refolding of a model heat-denatured protein can be monitored simultaneously by fluorescence microscopy and an enzymatic assay to probe the roles of proteostasis network components in protein quality control.

Saggi accoppiati per il monitoraggio delle proteine ​​in ripiegamento<em&gt; Saccharomyces cerevisiae</em

Proteostasis, defined as the combined processes of protein folding/biogenesis, refolding/repair, and degradation, is a delicate cellular balance that must ...

Measurement of mRNA Decay Rates in Saccharomyces cerevisiae Using rpb1-1 Strains

mRNA steady state levels vary depending on environmental conditions. Regulation of the steady state accumulation levels of an mRNA ensures that the correct amount of protein is synthesized for the cell&#8217;s specific growth conditions. One approach for measuring mRNA decay rates is inhibiting transcription and subsequently monitoring the disappearance of the already present mRNA. The rate of mRNA decay can then be quantified, and an accurate half-life can be determined utilizing several techniques. In S. cerevisiae, protocols that measure mRNA half-lives have been developed and include inhibiting transcription of mRNA using strains that harbor a temperature sensitive allele of RNA polymerase II, rpb1-1. Other techniques for measuring mRNA half-lives include inhibiting transcription with transcriptional inhibitors such as thiolutin or 1,10-phenanthroline, or alternatively, by utilizing mRNAs that are under the control of a regulatable promoter such as the galactose inducible promoter and the TET-off system. Here, we describe measurement of S. cerevisiae mRNA decay rates using the temperature sensitive allele of RNA polymerase II. This technique can be used to measure mRNA decay rates of individual mRNAs or genome-wide.

Measurement of mRNA Decay Rates in Saccharomyces cerevisiae Using rpb1-1 Strains

The steady state level of specific mRNAs is determined by the rate of synthesis and decay of the mRNA. Genome-wide mRNA degradation rates or the decay rates of specific mRNAs can be measured by determining mRNA half-lives. This protocol focuses on measurement of mRNA decay rates in Saccharomyces cerevisiae.

Misura di mRNA Decay Prezzi in<em&gt; Saccharomyces cerevisiae</em&gt; Utilizzo<em&gt; Rpb1-1</em&gt; Ceppi

mRNA steady state levels vary depending on environmental conditions. Regulation of the steady state accumulation levels of an mRNA ensures that the ...

Rapid Identification of Chemical Genetic Interactions in Saccharomyces cerevisiae

Determining the mode of action of bioactive chemicals is of interest to a broad range of academic, pharmaceutical, and industrial scientists. Saccharomyces cerevisiae, or budding yeast, is a model eukaryote for which a complete collection of ~6,000 gene deletion mutants and hypomorphic essential gene mutants are commercially available. These collections of mutants can be used to systematically detect chemical-gene interactions, i.e. genes necessary to tolerate a chemical. This information, in turn, reports on the likely mode of action of the compound. Here we describe a protocol for the rapid identification of chemical-genetic interactions in budding yeast. We demonstrate the method using the chemotherapeutic agent 5-fluorouracil (5-FU), which has a well-defined mechanism of action. Our results show that the nuclear TRAMP RNA exosome and DNA repair enzymes are needed for proliferation in the presence of 5-FU, which is consistent with previous microarray based bar-coding chemical genetic approaches and the knowledge that 5-FU adversely affects both RNA and DNA metabolism. The required validation protocols of these high-throughput screens are also described.

Rapid Identification of Chemical Genetic Interactions in Saccharomyces cerevisiae

Here we present a cost-effective method for defining chemical-genetic interactions in budding yeast. The approach is built on fundamental techniques in yeast molecular biology and is well suited for the mechanistic interrogation of small to medium collections of chemicals and other media environments.

Rapida identificazione dei chimici genetici Interactions in<em&gt; Saccharomyces cerevisiae</em

Determining the mode of action of bioactive chemicals is of interest to a broad range of academic, pharmaceutical, and industrial scientists. ...

Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening

Directed evolution in Saccharomyces cerevisiae offers many attractive advantages when designing enzymes for biotechnological applications, a process that involves the construction, cloning and expression of mutant libraries, coupled to high frequency homologous DNA recombination in vivo. Here, we present a protocol to create and screen mutant libraries in yeast based on the example of a fungal aryl-alcohol oxidase (AAO) to enhance its total activity. Two protein segments were subjected to focused-directed evolution by random mutagenesis and in vivo DNA recombination. Overhangs of ~50 bp flanking each segment allowed the correct reassembly of the AAO-fusion gene in a linearized vector giving rise to a full autonomously replicating plasmid. Mutant libraries enriched with functional AAO variants were screened in S. cerevisiae supernatants with a sensitive high-throughput assay based on the Fenton reaction. The general process of library construction in S. cerevisiae described here can be readily applied to evolve many other eukaryotic genes, avoiding extra PCR reactions, in vitro DNA recombination and ligation steps.

Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening

We present a detailed protocol to construct and screen mutant libraries for directed evolution campaigns in Saccharomyces cerevisiae.

Diretto Evolution Metodo<em&gt; Saccharomyces cerevisiae</em&gt;: Mutant Biblioteca Creazione e screening

Directed evolution in Saccharomyces cerevisiae offers many attractive advantages when designing enzymes for biotechnological applications, a process that ...

Cycloheximide Chase Analysis of Protein Degradation in Saccharomyces cerevisiae

Regulation of protein abundance is crucial to virtually every cellular process. Protein abundance reflects the integration of the rates of protein synthesis and protein degradation. Many assays reporting on protein abundance (e.g., single-time point western blotting, flow cytometry, fluorescence microscopy, or growth-based reporter assays) do not allow discrimination of the relative effects of translation and proteolysis on protein levels. This article describes the use of cycloheximide chase followed by western blotting to specifically analyze protein degradation in the model unicellular eukaryote, Saccharomyces cerevisiae (budding yeast). In this procedure, yeast cells are incubated in the presence of the translational inhibitor cycloheximide. Aliquots of cells are collected immediately after and at specific time points following addition of cycloheximide. Cells are lysed, and the lysates are separated by polyacrylamide gel electrophoresis for western blot analysis of protein abundance at each time point. The cycloheximide chase procedure permits visualization of the degradation kinetics of the steady state population of a variety of cellular proteins. The procedure may be used to investigate the genetic requirements for and environmental influences on protein degradation.

Cycloheximide Chase Analysis of Protein Degradation in Saccharomyces cerevisiae

Protein abundance reflects the rates of both protein synthesis and protein degradation. This article describes the use of cycloheximide chase followed by western blotting to analyze protein degradation in the model unicellular eukaryote, Saccharomyces cerevisiae (budding yeast).