1. Préparation des échantillons La première étape de Western blot est la préparation d&#39;échantillons. Pour préparer les échantillons pour l&#39;exécution d&#39;un gel de cellules et de tissus doivent être lysées pour libérer les protéines d&#39;intérêt. <ul><li> Une pratique, prêt à utiliser de réactifs qui est polyvalent et facile à utiliser pour l&#39;extraction des protéines solubles est CytoBuster ou PhosphoSafe. Ces tampons d&#39;extraction contiennent des détergents optimisé pour une extraction efficace des protéines solubles provenant de cellules de mammifères et d&#39;insectes. Le doux, non ioniques de composition de réactif CytoBuster Extraction des protéines permet l&#39;isolement des actifs endogènes fonctionnellement ou protéines exprimées sans avoir besoin d&#39;un traitement secondaire tels que sonication ou de gel / dégel. PhoshoSafe a l&#39;avantage de contenir quatre inhibiteurs de phosphatase. <ol><li> Pellet les cellules par centrifugation à faible vitesse (par exemple 5 min à 2500 xg), égoutter le culot cellulaire ainsi. </li><li> Resuspendre les cellules dans le réactif CytoBuster Extraction des protéines en utilisant 150 pi par 10 6 cellules (quantité optimale de réactif CytoBuster Extraction des protéines peut varier en fonction de la taille des cellules). </li><li> Incuber à température ambiante pendant 5 min. </li><li> Transférer dans un tube approprié et de spin pendant 5 min à 16000 xg à 4 ° C. </li><li> Transfert effacé surnageant (extrait cellulaire) dans un nouveau tube et procéder à l&#39;analyse. </li></ol></li><li> Pour l&#39;extraction des protéines spécialisées, nous recommandons d&#39;utiliser notre haute qualité Kits ProteoExtract. EMD a plus d&#39;une douzaine des kits pour l&#39;isolement des mitochondries, l&#39;extraction du protéome subcellulaire, l&#39;extraction des protéines transmembranaires, et bien d&#39;autres. S&#39;il vous plaît visitez notre page d&#39;atterrissage Ouest blot pour plus de détails. </li><li> EMD vend également une grande variété de protéase et inhibiteur de phosphatase ensembles cocktail. Dès que survient la lyse, la protéolyse, la déphosphorylation et de dénaturation de commencer. Ces événements peuvent être considérablement ralentie si les échantillons sont conservés sur la glace ou à 4 ° C en tout temps et les inhibiteurs appropriés sont ajoutés frais à la mémoire tampon de lyse. S&#39;il vous plaît visitez notre page d&#39;atterrissage Ouest blot pour plus de détails. </li></ul> 2. SDS-PAGE La deuxième étape du Western blot est la séparation des protéines. Les protéines sont séparées en fonction du poids moléculaire. <ul><li> Vous pouvez faire votre propre gel PAGE, cependant, nous allons utiliser une commercialement préfabriqués gel. <ol><li> Après la préparation de votre échantillon, vous êtes prêt à déterminer la concentration en protéines. EMD a deux kits pour ce pour mesurer la concentration, l&#39;un étant le Kit de non-ingérence et de protéines Assay l&#39;autre étant le kit BCA Protein Assay. </li><li> Une fois que la concentration en protéines est évaluée, nous sommes prêts à préparer notre échantillon pour le chargement du gel. Anticorps reconnaissent généralement une petite portion de la protéine d&#39;intérêt (appelé l&#39;épitope) et ce domaine peut résider dans la conformation 3D de la protéine. Pour permettre l&#39;accès de l&#39;anticorps à cette partie, il est nécessaire de déplier la protéine. </li><li> Pour dénaturer, utilisez un tampon de chargement avec le sulfate de détergents anioniques dénaturant dodécylsulfate de sodium (SDS), et faire bouillir le mélange à 95-100 ° C pendant 5 minutes. Un tampon de chargement facile et pratique à utiliser est tampon d&#39;échantillon 4X. </li></ol></li><li> Chargez la première voie du puits avec marqueur protéique Trail Mix. Ce marqueur a trois bandes de référence qui vous permettent de surveiller l&#39;électrophorèse. Lorsque le gel est coloré, les bandes 10 sont visibles allant de 10 à 225 kDa. </li><li> Remplir l&#39;appareil d&#39;électrophorèse avec beaucoup d&#39;tampon. Pour les gels PAGE, ce n&#39;est généralement 1X Tris-glycine. Pour les recettes de mémoire tampon détaillées, visitez la page Western blot. EMD offre de haute qualité réactifs tampons avec notre ligne de produit chimique OmniPur. Exécutez le gel à 220 pendant 1 heure. </li><li> Une fois que les protéines sont séparés, le gel coloration au bleu de Coomassie pour assurer les protéines ont migré équitablement et uniformément. RAPIDstain est une tache ultra-sensible qui est prêt à utiliser. Pas de décoloration est nécessaire. </li></ul> 3. La protéine de transfert Tout comme les protéines avec une charge électrique peut être amené à voyager à travers un gel dans un champ électrique, ne peut donc les protéines être transféré dans un champ électrique à partir du gel sur une membrane, étant soit PVDF ou de nitrocellulose. <ul><li> Aujourd&#39;hui, nous allons faire un transfert humide. En transfert humide, le gel et la membrane sont pris en sandwich entre une éponge et du papier (éponge / papier / gel / membrane / papier / éponge) et tous sont serrés ensemble, après s&#39;être assuré de bulles d&#39;air ont formé entre le gel et la membrane. Le sandwich est immergé dans du tampon de transfert à laquelle un champ électrique est appliqué. Les protéines chargées négativement de voyage vers l&#39;électrode chargée positivement, mais la membrane ne les arrête, les lie, et les empêche de continuer le. </li><li> Deux types de membranes sont disponibles: la nitrocellulose et de PVDF. Les deux fonctionnent bien. Aujourd&#39;hui, nous allons utiliser le PVDF. Membranes PVDF nécessitent trempage dans méthanol pour quelques minutes, suivi par du tampon de transfert de la glace froide pendant 5 minutes. Le gel a également besoin de s&#39;équilibrer pendant quelques minutes dans un tampon de transfert de la glace froide. Ne pas le faire peut rétrécir le gel pendant le transfert. </li><li> Le tampon pour le transfert par voie humide est 1X Tris-glycine avec 20% de méthanol. Les préparatifs de tampon détaillées sont disponibles sur notre site Web. </li><li> Une fois le transfert est terminé, c&#39;est une bonne idée de visualiser des protéines pour assurer le transfert, même avec des poches d&#39;air. Cela peut se faire facilement avec RedAlert Western Blot Stain. Cette tache est prêt à utiliser et de décoloration peut se faire facilement avec de l&#39;eau. </li></ul> 4. Les anticorps et les réactifs accessoires <ul><li> La première étape en faisant sonder et d&#39;anticorps à l&#39;antigène est de bloquer la membrane. Blocage de la membrane empêche la liaison de fond non spécifique. </li><li> Soit non gras du lait ou des BSA peut être utilisé comme une solution de blocage. Toutefois, lorsque vous utilisez anticorps phospho-spécifiques, il n&#39;est pas recommandé d&#39;utiliser du lait car cela fera de fond élevé. </li><li> EMD offre plusieurs de haute qualité réactifs de blocage, notamment SeaBlock, qui est un agent non-bloquant et de mammifères QuickBlocker BLOT, qui est préparé, prêt à utiliser bloquant. Nous avons aussi de haute qualité BSA (Fraction V) disponibles. <ol><li> Incuber la membrane 1 heure à température ambiante sous agitation douce. </li><li> Laver trois fois dans TBST ou PBST après incubation. Un moyen facile et pratique de faire ou de TBST PBST est d&#39;utiliser notre comprimés (PBS TWEEN Comprimés / SCT Tablets TWEEN) </li></ol></li><li> Une fois la membrane a été bloquée, vous êtes prêt à incuber avec l&#39;anticorps primaire. EMD a été propose un portefeuille étendu d&#39;anticorps exceptionnelle avec la meilleure garantie d&#39;anticorps dans l&#39;industrie depuis plus de 30 ans. N&#39;oubliez pas que tous les anticorps EMD, nous offrons un plein 100% sans risque de garantie. Achat d&#39;un anticorps et l&#39;utiliser pour toute la spécificité d&#39;espèce ou de l&#39;application que vous désirez. Si les anticorps ne fonctionnent pas à votre satisfaction, nous vous fournirons un crédit complet pour être utilisé sur n&#39;importe quel autre produit. Pour plus de détails, s&#39;il vous plaît visitez notre page web occidentaux buvard. <ol><li> Aujourd&#39;hui, nous allons être en incubation de nos anticorps primaire avec une solution d&#39;une SignalBoost. SignalBoost est un excellent produit qui permet à votre signal pour être amélioré de manière significative. Simplement incuber votre anticorps primaire dans la Solution 1 et incuber pendant 1 heure ou comme vous le feriez normalement. Il n&#39;est pas nécessaire d&#39;ajouter d&#39;autres agents de blocage. Alternativement, vous pouvez utiliser BSA ou poudre de lait écrémé comme agent de blocage. </li><li> Laver avec du TBST. Nous faisons TBST utilisant le prêt-à-dissoudre le comprimé TBST. </li><li> Incuber vos anticorps secondaire en utilisant la solution 2 de SignalBoost. Incuber l&#39;anticorps secondaire dans le tampon de blocage pendant 1 heure. Lavez la membrane à nouveau plusieurs fois avec TBST. </li></ol></li></ul> 5. Détection Pour conjuguer HRP Anticorps secondaires, ECL est traditionnellement utilisé. Un excellent réactif ECL que nous offrons est RapidStep. Les avantages de RapidStep sont que pas de mélange de luminal ou un amplificateur est nécessaire. Il suffit de vaporiser la membrane à quelques reprises et de développer en utilisant les films radiographiques. RapidStep offre une sensibilité faible pictogramme ainsi que émettant de la lumière pour un maximum de 2 heures après l&#39;addition du substrat.

<ol>
	<li>Towbin, H., Staehelin, T., Gordon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+transfer+of+proteins+from+polyacrylamide+gels+to+nitrocellulose+sheets:+procedure+and+some+applications.">Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.</a> Proc Natl Acad Sci U S A. 76 (9), 4350-4354 (1979).</li><li>Renart, J., Reiser, J., Stark, G. R., R, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfer+of+proteins+from+gels+to+diazobenzyloxymethyl-paper+and+detection+with+antisera:+a+method+for+studying+antibody+specificity+and+antigen+structure.">Transfer of proteins from gels to diazobenzyloxymethyl-paper and detection with antisera: a method for studying antibody specificity and antigen structure.</a> Proc Natl Acad Sci U S A. 76 (7), 3116-3120 (1979).</li><li>Burnette, W. N. '. W. e. s. t. e. r. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=blotting':+electrophoretic+transfer+of+proteins+from+sodium+dodecyl+sulfate+polyacrylamide+gels+to+unmodified+nitrocellulose+and+radiographic+detection+with+antibody+and+radioiodinated+protein+A.">blotting': electrophoretic transfer of proteins from sodium dodecyl sulfate polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A.</a> Analytical Biochemistry. 112, 195-203 (1981).</li><li>Ambroz, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+quantification+accuracy+for+Western+blots+Image+Analysis.">Improving quantification accuracy for Western blots Image Analysis.</a> , (2006).</li><li>Quan, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactive+oxygen+species-mediated+endoplasmic+reticulum+stress+and+mitochondrial+dysfunction+contribute+to+cirsimartitin-induced+apoptosis+in+human+gallbladder+carcinoma+GBC-SD+cells.">Reactive oxygen species-mediated endoplasmic reticulum stress and mitochondrial dysfunction contribute to cirsimartitin-induced apoptosis in human gallbladder carcinoma GBC-SD cells.</a> Cancer Lett Article. , (2010).</li><li>O'Malley, D. e. r. v. i. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alterations+in+colonic+corticotrophin-releasing+factor+receptors+in+the+maternally+separated+rat+model+of+irritable+bowel+syndrome:+Differential+effects+of+acute+psychological+and+physical+stressors.">Alterations in colonic corticotrophin-releasing factor receptors in the maternally separated rat model of irritable bowel syndrome: Differential effects of acute psychological and physical stressors.</a> Peptides. 31 (4), 662-670 (2010).</li></ol>

Les auteurs Anna Eslami et Jesse Lujan sont employés par EMD Chemicals Inc qui produit des réactifs et des instruments utilisés dans le présent article.

Dans cette vidéo de présentation, nous avons mis en évidence les grandes étapes de Western blot qui sont la préparation des échantillons, SDS-PAGE, la membrane bloquant / sondage avec des anticorps, et de détection. Pour chaque étape du processus, des protocoles et des réactifs appropriés appropriés devraient être utilisés pour atteindre des résultats de haute qualité.

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		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>CytoBuster&trade; Protein Extraction Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71009</td>
<td><a href="http://www.emdbiosciences.com/cytobuster">www.emdbiosciences.com/cytobuster</a> <a href="http://www.merck4biosciences.com/cytobuster">www.merck4biosciences.com/cytobuster</a></td>
</tr>
<tr>
<td>PhosphoSafe&trade; Extraction Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71296</td>
<td><a href="http://www.emdbiosciences.com/phosphosafe">www.emdbiosciences.com/phosphosafe</a> <a href="http://www.merck4biosciences.com/phosphosafe">www.merck4biosciences.com/phosphosafe</a></td>
</tr>
<tr>
<td>Non-Interfering Protein Assay&trade; Kit</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>488250</td>
<td><a href="http://www.emdbiosciences.com/noninterfering">www.emdbiosciences.com/noninterfering</a> <a href="http://www.merck4biosciences.com/noninterfering">www.merck4biosciences.com/noninterfering</a></td>
</tr>
<tr>
<td>BCA Protein Assay Kit </td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71285</td>
<td><a href="http://www.emdbiosciences.com/BCA">www.emdbiosciences.com/BCA</a> <a href="http://www.merck4biosciences.com/BCA">www.merck4biosciences.com/BCA</a></td>
</tr>
<tr>
<td>4X SDS Sample Buffer </td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>70607</td>
<td><a href="http://www.emdbiosciences.com/4XSDS">www.emdbiosciences.com/4XSDS</a> <a href="http://www.merck4biosciences.com/4XSDS">www.merck4biosciences.com/4XSDS</a></td>
</tr>
<tr>
<td>Trail Mix&trade; Protein Markers</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>70980</td>
<td><a href="http://www.emdbiosciences.com/trailmix">www.emdbiosciences.com/trailmix</a> <a href="http://www.merck4biosciences.com/trailmix">www.merck4biosciences.com/trailmix</a></td>
</tr>
<tr>
<td>ProteoExtract&trade; Protein Extraction Kits</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>&nbsp;</td>
<td><a href="http://www.emdbiosciences.com/proteoextract">www.emdbiosciences.com/proteoextract</a> <a href="http://www.merck4biosciences.com/proteoextract">www.merck4biosciences.com/proteoextract</a></td>
</tr>
<tr>
<td>OmniPur&reg; Products</td>
<td>&nbsp;</td>
<td>EMD Chemicals</td>
<td>&nbsp;</td>
<td><a href="http://www.emdbiosciences.com/omnipur">www.emdbiosciences.com/omnipur</a></td>
</tr>
<tr>
<td>RAPIDstain&trade; Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>553215</td>
<td><a href="http://www.emdbiosciences.com/rapidstain">www.emdbiosciences.com/rapidstain</a> <a href="http://www.merck4biosciences.com/rapidstain">www.merck4biosciences.com/rapidstain</a></td>
</tr>
<tr>
<td>RedAlert&trade; 10X Western Blot Stain</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>71078</td>
<td><a href="http://www.emdbiosciences.com/redalert">www.emdbiosciences.com/redalert</a> <a href="http://www.merck4biosciences.com/redalert">www.merck4biosciences.com/redalert</a></td>
</tr>
<tr>
<td>SeaBlock&trade; Reagent, Salmon Plasma</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>558300</td>
<td><a href="http://www.emdbiosciences.com/seablock">www.emdbiosciences.com/seablock</a> <a href="http://www.merck4biosciences.com/seablock">www.merck4biosciences.com/seablock</a></td>
</tr>
<tr>
<td>BLOT-QuickBlocker Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>WB57</td>
<td><a href="http://www.emdbiosciences.com/quickblocker">www.emdbiosciences.com/quickblocker</a> <a href="http://www.merck4biosciences.com/quickblocker">www.merck4biosciences.com/quickblocker</a></td>
</tr>
<tr>
<td>Albumin, Bovine Serum, Fraction V</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>12660</td>
<td><a href="http://www.emdbiosciences.com/bovineserum">www.emdbiosciences.com/bovineserum</a> <a href="http://www.merck4biosciences.com/bovineserum">www.merck4biosciences.com/bovineserum</a></td>
</tr>
<tr>
<td>PBS-TWEEN&reg; Tablets</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>524653</td>
<td><a href="http://www.emdbiosciences.com/PBST">www.emdbiosciences.com/PBST</a> <a href="http://www.merck4biosciences.com/PBST">www.merck4biosciences.com/PBST</a></td>
</tr>
<tr>
<td>TBS-TWEEN&reg; Tablets</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>524753</td>
<td><a href="http://www.emdbiosciences.com/TBST">www.emdbiosciences.com/TBST</a> <a href="http://www.merck4biosciences.com/TBST">www.merck4biosciences.com/TBST</a></td>
</tr>
<tr>
<td>SignalBoost&trade; Immunoreaction Enhancer Kit</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>407207</td>
<td><a href="http://www.emdbiosciences.com/signalboost">www.emdbiosciences.com/signalboost</a> <a href="http://www.merck4biosciences.com/signalboost">www.merck4biosciences.com/signalboost</a></td>
</tr>
<tr>
<td>RapidStep&trade; ECL Reagent</td>
<td>&nbsp;</td>
<td>EMD Chemicals/Merck KGaA</td>
<td>345818</td>
<td><a href="http://www.emdbiosciences.com/rapidstep">www.emdbiosciences.com/rapidstep</a> <a href="http://www.merck4biosciences.com/rapidstep">www.merck4biosciences.com/rapidstep</a></td>
</tr>		</tbody>
		</table>
		</div>

western blotting: sample preparation to detection

Western blot est une technique d&#39;analyse utilisée pour détecter des protéines spécifiques dans un échantillon donné d&#39;homogénat de tissu ou de l&#39;extrait. Elle utilise l&#39;électrophorèse sur gel pour séparer les protéines natives ou dénaturées par la longueur du polypeptide (conditions dénaturantes) ou par la structure en 3-D de la protéine (natif / non-dénaturantes). Les protéines sont ensuite transférées sur une membrane (typiquement de nitrocellulose ou PVDF), où ils sont sondés (détectée) utilisant des anticorps spécifiques à la protéine cible.

Watch this Scientific Journal Video about Western Blotting: Sample Preparation to Detection at JoVE.com

Western Blotting: Sample Preparation to Detection

Western blot est une technique d&#39;analyse utilisée pour détecter des protéines spécifiques dans un échantillon donné d&#39;homogénat de tissu ou de l&#39;extrait.

Western Blot: préparation d&#39;échantillons à la détection

Western blotting is an analytical technique used to detect specific proteins in a given sample of tissue homogenate or extract. It uses gel ...

western-blotting-sample-preparation-to-detection

Research

JoVE Journal

Biology

138.9K vues.  EMD Chemicals Inc.. Western blot est une technique d'analyse utilisée pour détecter des protéines spécifiques dans un échantillon donné d'homogénat de tissu ou de l'extrait.

Vidéo: Western Blotting: Sample Preparation to Detection

MALDI Sample Preparation: the Ultra Thin Layer Method

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) 1,2. The ultra-thin layer method involves the production of a substrate layer of matrix crystals (alpha-cyano-4-hydroxycinnamic acid) on the sample plate, which serves as a seeding ground for subsequent crystallization of a matrix/analyte mixture. Advantages of the ultra-thin layer method over other sample deposition approaches (e.g. dried droplet) are that it provides (i) greater tolerance to impurities such as salts and detergents, (ii) better resolution, and (iii) higher spatial uniformity. This method is especially useful for the accurate mass determination of proteins. The protocol was initially developed and optimized for the analysis of membrane proteins and used to successfully analyze ion channels, metabolite transporters, and receptors, containing between 2 and 12 transmembrane domains 2. Since the original publication, it has also shown to be equally useful for the analysis of soluble proteins. Indeed, we have used it for a large number of proteins having a wide range of properties, including those with molecular masses as high as 380 kDa 3. It is currently our method of choice for the molecular mass analysis of all proteins. The described procedure consistently produces high-quality spectra, and it is sensitive, robust, and easy to implement.

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS).

Préparation des échantillons MALDI: la méthode de la couche ultra mince

This video demonstrates the preparation of an ultra-thin matrix/analyte layer for analyzing peptides and proteins by Matrix-Assisted Laser Desorption ...

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Biologie

Western Blotting Using the Invitrogen NuPage Novex Bis Tris MiniGels

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the relative amount of the protein present in different samples, and analyze the results of co-immunoprecipitation experiments. In this method, a target protein is detected with a specific primary antibody in a given sample of tissue homogenate or extract. Protein separation according to molecular weight is achieved using denaturing SDS-PAGE. After transfer to a membrane, the target protein is probed with a specific primary antibody and detected by chemiluminescence.
Since its first description, the western-blotting technique has undergone several improvements, including pre-cast gels and user-friendly equipment. In our laboratory, we have chosen to use the commercially available NuPAGE electrophoresis system from Invitrogen. It is an innovative neutral pH, discontinuous SDS-PAGE, pre-cast mini-gel system. This system presents several advantages over the traditional Laemmli technique including: i) a longer shelf life of the pre-cast gels ranging from 8 months to 1 year; ii) a broad separation range of molecular weights from 1 to 400 kDa depending of the type of gel used; and iii) greater versatility (range of acrylamide percentage, the type of gel, and the ionic composition of the running buffer).
The procedure described in this video article utilizes the Bis-Tris discontinuous buffer system with 4-12% Bis-Tris gradient gels and MES running buffer, as an illustration of how to perform a western-blot using the Invitrogen NuPAGE electrophoresis system. In our laboratory, we have obtained good and reproducible results for various biochemical applications using this western-blotting method.

This technical article describes a standard western-blotting procedure using the commercially available NuPAGE electrophoresis Mini-Gel system from Invitrogen.

Western blot en utilisant l&#39;Invitrogen NuPage Novex Bis Tris minigels

Western Blotting (or immunoblotting) is a standard laboratory procedure allowing investigators to verify the expression of a protein, determine the ...

Proteomic Sample Preparation from Formalin Fixed and Paraffin Embedded Tissue

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale quantitative analysis of formalin fixed and paraffin embedded (FFPE) tissue. The procedure comprises four distinct steps. The first one is the preparation of sections from the FFPE material and microdissection of cells of interest. In the second step the isolated cells are lysed and processed using 'filter aided sample preparation' (FASP) technique. In this step, proteins are depleted from reagents used for the sample lysis and are digested in two-steps using endoproteinase LysC and trypsin. 
After each digestion, the peptides are collected in separate fractions and their content is determined using a highly sensitive fluorescence measurement. Finally, the peptides are fractionated on 'pipette-tip' microcolumns. The LysC-peptides are separated into 4 fractions whereas the tryptic peptides are separated into 2 fractions. In this way prepared samples allow analysis of proteomes from minute amounts of material to a depth of 10,000 proteins. Thus, the described workflow is a powerful technique for studying diseases in a system-wide-fashion as well as for identification of potential biomarkers and drug targets.

Archival formalin fixed and paraffin embedded (FFPE) clinical samples are valuable material for investigation of diseases. Here we demonstrate a sample preparation workflow allowing in-depth proteomic analysis of microdissected FFPE tissue.

Protéomique Préparation de l&#39;échantillon de formol et inclus en paraffine fixe tissus

Preserved clinical material is a unique source for proteomic investigation of human disorders. Here we describe an optimized protocol allowing large scale ...

V3 Stain-free Workflow for a Practical, Convenient, and Reliable Total Protein Loading Control in Western Blotting

The western blot is a very useful and widely adopted lab technique, but its execution is challenging. The workflow is often characterized as a &#34;black box&#34; because an experimentalist does not know if it has been performed successfully until the last of several steps. Moreover, the quality of western blot data is sometimes challenged due to a lack of effective quality control tools in place throughout the western blotting process. Here we describe the V3 western workflow, which applies stain-free technology to address the major concerns associated with the traditional western blot protocol. This workflow allows researchers: 1) to run a gel in about 20-30 min; 2) to visualize sample separation quality within 5 min after the gel run; 3) to transfer proteins in 3-10 min; 4) to verify transfer efficiency quantitatively; and most importantly 5) to validate changes in the level of the protein of interest using total protein loading control. This novel approach eliminates the need of stripping and reprobing the blot for housekeeping proteins such as &#946;-actin, &#946;-tubulin, GAPDH, etc. The V3 stain-free workflow makes the western blot process faster, transparent, more quantitative&#160;and reliable.

V3 workflow is a western blot procedure using stain-free gels. The stain-free technology allows researchers to visualize protein separation quality, to verify the transfer efficiency, and most importantly, to validate the change in the protein of interest using total protein quantification as a reliable loading control.

Flux de travail sans taches V3 pour un contrôle pratique, pratique et fiable de la charge totale en protéines dans Western Blotting

The western blot is a very useful and widely adopted lab technique, but its execution is challenging. The workflow is often characterized as a &#34;black ...

The Fastest Western in Town: A Contemporary Twist on the Classic Western Blot Analysis

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of Western blotting has several drawbacks that include low quality resolution, spurious bands, decreased sensitivity, and poor protein integrity. Recent advances have drastically improved numerous aspects of the standard Western blot protocol to produce higher qualitative and quantitative data. The Bis-Tris gel system, an alternative to the conventional Laemmli system, generates better protein separation and resolution, maintains protein integrity, and reduces electrophoresis to a 35 min run time. Moreover, the iBlot dry blotting system, dramatically improves the efficacy and speed of protein transfer to the membrane in 7 min, which is in contrast to the traditional protein transfer methods that are often more inefficient with lengthy transfer times. In combination with these highly innovative modifications, protein detection using infrared fluorescent imaging results in higher-quality, more accurate and consistent data compared to the standard Western blotting technique of chemiluminescence. This technology can simultaneously detect two different antigens on the same membrane by utilizing two-color near-infrared dyes that are visualized in different fluorescent channels. Furthermore, the linearity and broad dynamic range of fluorescent imaging allows for the precise quantification of both strong and weak protein bands. Thus, this protocol describes the key improvements to the classic Western blotting method, in which these advancements significantly increase the quality of data while greatly reducing the performance time of this experiment.

This protocol explores the latest advancements in performing Western blot analyses.&#160;These novel modifications employ a Bis-Tris gel system with a 35&#160;min electrophoresis run time, a 7&#160;min dry blotting transfer system, and infrared fluorescent protein detection and imaging that generates higher resolution, quality, sensitivity, and improved accuracy of Western data.

Le plus rapide de l&#39;Ouest dans la ville: une touche contemporaine sur l&#39;analyse classique western blot

The Western blot techniques that were originally established in the late 1970s are still actively utilized today. However, this traditional method of ...

A Guide to Modern Quantitative Fluorescent Western Blotting with Troubleshooting Strategies

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins within complex biological samples. Since then, western blotting methodology has become a common component of the molecular biologists experimental repertoire. A cursory search of PubMed using the term &#8220;western blot&#8221; suggests that in excess of two hundred and twenty thousand published manuscripts have made use of this technique by the year 2014. Importantly, the last ten years have seen technical imaging advances coupled with the development of sensitive fluorescent labels which have improved sensitivity and yielded even greater ranges of linear detection. The result is a now truly Quantifiable Fluorescence based Western Blot (QFWB) that allows biologists to carry out comparative expression analysis with greater sensitivity and accuracy than ever before. Many &#8220;optimized&#8221; western blotting methodologies exist and are utilized in different laboratories. These often prove difficult to implement due to the requirement of subtle but undocumented procedural amendments. This protocol provides a comprehensive description of an established and robust QFWB method, complete with troubleshooting strategies.

The advancement of western blotting using fluorescence has allowed detection of subtle changes in protein expression enabling quantitative analyses. Here we describe a robust methodology for detection of a range of proteins across a variety of species and tissue types. A strategy to overcome common technical problems is also provided.

Un Guide to Modern quantitative fluorescente Western blot avec des stratégies de dépannage

The late 1970s saw the first publicly reported use of the western blot, a technique for assessing the presence and relative abundance of specific proteins ...

Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins

Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against invading pathogens. The main role of these macromolecules is to facilitate particle trapping and clearance while promoting lubrication of the mucosa. During protein synthesis, mucins undergo intense O-glycosylation and multimerization, which dramatically increase the mass and size of these molecules. These post-translational modifications are critical for the viscoelastic properties of mucus. As a result of the complex biochemical and biophysical nature of these molecules, working with mucins provides many challenges that cannot be overcome by conventional protein analysis methods. For instance, their high-molecular-weight prevents electrophoretic migration via regular polyacrylamide gels and their sticky nature causes adhesion to experimental tubing. However, investigating the role of mucins in health (e.g., maintaining mucosal integrity) and disease (e.g., hyperconcentration, mucostasis, cancer) has recently gained interest and mucins are being investigated as a therapeutic target. A better understanding of the production and function of mucin macromolecules may lead to novel pharmaceutical approaches, e.g., inhibitors of mucin granule exocytosis and/or mucolytic agents. Therefore, consistent and reliable protocols to investigate mucin biology are critical for scientific advancement. Here, we describe conventional methods to separate mucin macromolecules by electrophoresis using an agarose gel, transfer protein into nitrocellulose membrane, and detect signal with mucin-specific antibodies as well as infrared fluorescent gel reader. These techniques are widely applicable to determine mucin quantitation, multimerization and to test the effects of pharmacological compounds on mucins.

Mucins are high-molecular-weight glycoconjugates, with size ranging from 0.2 to 200 megadalton (MDa). As a result of their size, mucins do not penetrate conventional polyacrylamide gels and require larger pores for separation. We provide a detailed protocol for mucin agarose gel electrophoresis to assess relative quantification and study polymer assembly.

Mucine Agarose Gel Electrophoresis: Western Blot pour les glycoprotéines de haut poids moléculaire,


Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against ...

Sample Preparation for Mass Cytometry Analysis

Mass cytometry utilizes antibodies conjugated with heavy metal labels, an approach that has greatly increased the number of parameters and opportunities for deep analysis well beyond what is possible with conventional fluorescence-based flow cytometry. As with any new technology, there are critical steps that help ensure the reliable generation of high-quality data. Presented here is an optimized protocol that incorporates multiple techniques for the processing of cell samples for mass cytometry analysis. The methods described here will help the user avoid common pitfalls and achieve consistent results by minimizing variability, which can lead to inaccurate data. To inform experimental design, the rationale behind optional or alternative steps in the protocol and their efficacy in uncovering new findings in the biology of the system being investigated is covered. Lastly, representative data is presented to illustrate expected results from the techniques presented here.

This article describes the collection and processing of samples for mass cytometry analysis.

Préparation d&#39;échantillons pour l&#39;analyse de masse Cytométrie

Mass cytometry utilizes antibodies conjugated with heavy metal labels, an approach that has greatly increased the number of parameters and opportunities ...

Sample Preparation and Imaging of Exosomes by Transmission Electron Microscopy

Exosomes are nano-sized extracellular vesicles secreted by body fluids and are known to represent the characteristics of cells that secrete them. The contents and morphology of the secreted vesicles reflect cell behavior or physiological status, for example cell growth, migration, cleavage, and death. The exosomes&#39; role may depend highly on size, and the size of exosomes varies from 30 to 300 nm. The most widely used method for exosome imaging is negative staining, while other results are based on Cryo-Transmission Electron Microscopy, Scanning Electron Microscopy, and Atomic Force Microscopy. The typical exosome&#39;s morphology assessed through negative staining is a cup-shape, but further details are not yet clear. An exosome well-characterized through structural study is necessary particular in medical and pharmaceutical fields. Therefore, function-dependent morphology should be verified by electron microscopy techniques such as labeling a specific protein in the detailed structure of exosome. To observe detailed structure, ultrathin sectioned images and negative stained images of exosomes were compared. In this protocol, we suggest transmission electron microscopy for the imaging of exosomes including negative staining, whole mount immuno-staining, block preparation, thin section, and immuno-gold labelling.

This protocol describes the various techniques necessary for transmission electron microscopy including negative staining, ultrathin sectioning for detailed structure, and immuno-gold labelling to determine the positions of specific proteins in exosomes.

Préparation des échantillons et l’imagerie des Exosomes par microscopie électronique à Transmission

Exosomes are nano-sized extracellular vesicles secreted by body fluids and are known to represent the characteristics of cells that secrete them. The ...

Miniaturized Sample Preparation for Transmission Electron Microscopy

Due to recent technological progress, cryo-electron microscopy (cryo-EM) is rapidly becoming a standard method for the structural analysis of protein complexes to atomic resolution. However, protein isolation techniques and sample preparation methods for EM remain a bottleneck. A relatively small number (100,000 to a few million) of individual protein particles need to be imaged for the high-resolution analysis of proteins by the single particle EM approach, making miniaturized sample handling techniques and microfluidic principles feasible.
A miniaturized, paper-blotting-free EM grid preparation method for sample pre-conditioning, EM grid priming and post processing that only consumes nanoliter-volumes of sample is presented. The method uses a dispensing system with sub-nanoliter precision to control liquid uptake and EM grid priming, a platform to control the grid temperature thereby determining the relative humidity above the EM grid, and a pick-and-plunge-mechanism for sample vitrification. For cryo-EM, an EM grid is placed on the temperature-controlled stage and the sample is aspirated into a capillary. The capillary tip is positioned in proximity to the grid surface, the grid is loaded with the sample and excess is re-aspirated into the microcapillary. Subsequently, the sample film is stabilized and slightly thinned by controlled water evaporation regulated by the offset of the platform temperature relative to the dew-point. At a given point the pick-and-plunge mechanism is triggered, rapidly transferring the primed EM grid into liquid ethane for sample vitrification. Alternatively, sample-conditioning methods are available to prepare nanoliter-sized sample volumes for negative stain (NS) EM.
The methodologies greatly reduce sample consumption and avoid approaches potentially harmful to proteins, such as the filter paper blotting used in conventional methods. Furthermore, the minuscule amount of sample required allows novel experimental strategies, such as fast sample conditioning, combination with single-cell lysis for &#34;visual proteomics,&#34; or &#34;lossless&#34; total sample preparation for quantitative analysis of complex samples.

An instrument and methods for the preparation of nanoliter-sized sample volumes for transmission electron microscopy is presented. No paper-blotting steps are required, thus avoiding the detrimental consequences this can have for proteins, significantly reducing sample loss and enabling the analysis of single cell lysate for visual proteomics.

Préparation de l’échantillon miniaturisé pour la microscopie électronique à Transmission

Due to recent technological progress, cryo-electron microscopy (cryo-EM) is rapidly becoming a standard method for the structural analysis of protein ...