Ce travail a été soutenu par des subventions de la Fondation canadienne pour l&#39;innovation (FCI), l&#39;Institut canadien de recherche en santé du Canada (IRSC), et les sciences naturelles et en génie du Canada (CRSNG).

Partie 1: La perturbation de la grippe A Virion <ol><li> Ajouter 750 pi de tampon de MNT (20 mM MES, 150 mM NaCl, 30 mM Tris, pH 7,5) dans un tube à centrifuger Beckman polycarbonate (11 mm x 34 mm), conçu pour s&#39;intégrer dans un rotor TLA-120.2 pour une utilisation dans un Optima Beckman Max-E ultracentrifugation. </li><li> Ajouter 500 ul de la grippe A (H3N2 X-31 A/AICHI/68 souche; 2 mg / ml) dans ce tube. Mélanger le virus avec le tampon de MNT par pipetage de haut en bas plusieurs fois. </li><li> Centrifuger pendant 10 minutes à 109 000 xg, 4 ° C, dans un Beckman Optima Max-E centrifugeuse à l&#39;aide d&#39;un rotor TLA-120.2. </li><li> Enlever le surnageant et resuspendre le culot dans 500 ul de tampon perturbations (100 mM de KCl, 5 mM MgCl 2, 5% (p / v) de glycérol, 50 mM octylglucoside, 10 mg / ml lysolécithine, 1,5 mM de dithiothréitol, 100 mM MES, pH 5,5). </li><li> Vortex vigoureusement, puis agiter à 31 ° C pendant 20 minutes dans une thermomixer Eppendorf. </li></ol> Partie 2: Dégradé glycérol Velocity culot de centrifugation <ol><li> Préparer un gradient de glycérol en plaçant les montants suivants de la glycérine dans un tube à centrifuger Beckman UltraClear (13 mm x 51 mm): 1 ml à 70% (v / v) de glycérol, 0,75 ml de glycérol 50%, 0,375 ml de glycérol 40%, et 1,8 ml de glycérol 33%. Des solutions de glycérol sont fabriqués en mélangeant glycérine pure avec un tampon de NM (150 mM NaCl, 50 mM MES, pH 5,5). Également préparer un tube d&#39;équilibrage contenant à la fois le glycérol et tampon. </li><li> Vortex, le perturbé l&#39;échantillon viral à nouveau, et le charger sur le gradient de glycérol. </li><li> Centrifuger le gradient de 3,75 heures à 217 000 xg, 4 ° C, dans un Beckman MLS-50-balancer Rotor. </li><li> Après la centrifugation est terminée, collecter manuellement 250 aliquotes du gradient à partir du haut du tube. Gardez fractions sur la glace ou à 4 ° C. </li></ol> Partie 3: Analyse des fractions du gradient de glycérol par électrophorèse sur gel de polyacrylamide SDS <ol><li> Retirer 20 ul de chaque fraction dans un nouveau tube. </li><li> Ajouter 5 ul de tampon d&#39;échantillon 5x SDS-PAGE. </li><li> Chauffer à 95 ° C pendant 5 minutes. </li><li> Isoler les échantillons brièvement et les charger sur un gel de polyacrylamide 10%, et inclure des marqueurs de poids moléculaire dans un des puits. </li><li> Exécuter les échantillons sur le gel jusqu&#39;à ce que le colorant de chargement bleu de bromophénol atteigne près du fond du gel. </li><li> Tache le gel au bleu de Coomassie. </li></ol> Partie 4: concentration des fractions vRNP <ol><li> Choisissez les fractions de glycérol contenant principalement des NP, les combiner, et les distribuer dans des tubes de centrifugeuse Beckman deux polycarbonate (11 mm x 34 mm). </li><li> Remplir chaque tube avec diéthyl pyrocarbonate (DEPC)-traité l&#39;eau ultra-pure, et une pipette de haut en bas plusieurs fois pour mélanger. </li><li> Centrifuger pendant 4,5 heures à 157 000 xg, 4 ° C, dans un Beckman TLA-120.2 du rotor. </li><li> Enlever le surnageant et resuspendre le culot dans 50 ul d&#39;eau traitée au DEPC. </li><li> Si désiré, le 280 A du vRNPs concentrée peut être mesurée. Comme NP est le composant présent dans la majeure fractions regroupées, une estimation de la molarité de NP peut être calculée à l&#39;aide de son coefficient d&#39;extinction de 55 350 M -1 cm -1 (tel que déterminé par le biais ProtParam 3). </li><li> Aliquoter l&#39;vRNPs purifiée, et les stocker à -80 ° C pour une utilisation ultérieure. </li></ol> Partie 5: coloration négative de vRNPs <ol><li> Diluez 1 pl de purifier vRNP en 9 pl d&#39;fraîchement faite et filtrés-deux tampons MNT (20 mM MES, 150 mM NaCl, 30 mM Tris, pH 7,5). D&#39;autres tampons sont également OK pour diluer le vRNPs et pour laver la grille échantillon (étape 5.5), mais ne pas utiliser du PBS, si l&#39;acétate d&#39;uranyle est utilisé pour la coloration négative. </li><li> Décharge luminescente un spécimen (TEM de cuivre) de grille préalablement revêtu d&#39;une pellicule de carbone et de parlodion pendant 30 secondes. </li><li> Tenez la grille spécimens fraîchement déchargé brillent avec des pincettes, et d&#39;appliquer une baisse de 5 pl d&#39;vRNP diluée sur la grille spécimen. </li><li> Laisser la goutte d&#39;échantillon sur la grille pendant 8 minutes. </li><li> En attendant, placer une petite bande de Parafilm sur le banc, et se dispenser 2 gouttes contenant 10 ul de tampon à chaque MNT (pour laver la grille), et une baisse de 80 pl de la solution de coloration fraîchement préparée (1 molybdate d&#39;ammonium ou 1% acétate d&#39;uranyle%) sur le Parafilm. </li><li> Après les 8 minutes d&#39;adsorption, la mèche une partie de la solution échantillon de la grille de spécimen avec un morceau de papier filtre (coupés en triangles). Ne laissez pas la grille de spécimen à sec. </li><li> Laver la grille spécimen dans 2 gouttes contenant 10 ul de tampon à chaque MNT pour un temps total de 1 minute. Cela se fait en abaissant attentivement la grille d&#39;échantillon sur la chute, puis évacuant une partie de la solution échantillon de la grille de spécimen avec un morceau de papier filtre (sans laisser la grille échantillon sec). </li><li> Immédiatement après l&#39;évacuation hors de la dernière goutte de tampon de la grille spécimen, completLy plonger la grille échantillon dans la gouttelette tache et attendre 1 minute. </li><li> Complètement hors mèche de la solution aux taches de la grille de spécimen avec un morceau de papier filtre. </li><li> Autoriser la grille spécimen sécher à l&#39;air pendant plusieurs minutes avant l&#39;observation au microscope électronique à transmission. </li></ol> Partie 6: Résultats du représentant: <img src="/files/ftp_upload/old/1105_2009_1_22_1/1105_Figure2.png" alt="Figure 2" width="600" height="215" /> Figure 1 Comme la grippe A NP (~ 56 kDa) est la principale protéine dans les complexes de ribonucléoprotéines virales, la bande NP est généralement la plus forte bande dans les fractions contenant le vRNPs (figure 1). En plus de NP, chaque vRNP la grippe contient également une copie d&#39;une polymérase ARN trimérique (poids moléculaire kDa 82, 86 et 86,5) complexes. Ceux-ci peuvent ou peuvent ne pas être visible par coloration au bleu de Coomassie parce que leur abondance est faible comparée à celle de NP. Les polymérases, cependant, peuvent être détectés si, au lieu d&#39;un bleu Commassie tache, une coloration à l&#39;argent du gel est effectué. La protéine de la matrice de la grippe M1 (~ 28 kDa) devrait être minimalement présents dans les fractions où les fractions NP pic de protéine sont présents. <img src="/files/ftp_upload/old/1105_2009_1_22_2/1105_3.png" alt="Figure 3" width="600" height="360" /> Figure 2 VRNPs négativement colorées comme visualisées sous un microscope électronique à transmission devrait donner vRNPs qui ressemblent à des particules en forme de tige, de longueur variable qui sont environ 30 nm à 120 nm de longueur (Figure 2a). Le NP oligomérique est organisé comme une chaîne de molécules de NP qui est encore plié dans une structure hélicoïdale à double répétition, des boucles ainsi de suite deux extrémités de ces particules en forme de tige peut parfois être vu (Figure 2b).

<ol>
	<li>Kemler, I., Whittaker, G., Helenius, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+import+of+microinjected+influenza+virus+ribonucleoproteins.">Nuclear import of microinjected influenza virus ribonucleoproteins.</a> Virology. 202, 1028-1033 (1994).</li><li>Wu, W. W. H., Weaver, L. L., Pant&#233;, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructural+analysis+of+the+nuclear+localization+sequences+on+influenza+a+ribonucleoprotein+complexes.">Ultrastructural analysis of the nuclear localization sequences on influenza a ribonucleoprotein complexes.</a> J Mol Biol. 374, 910-916 (2007).</li><li>Gasteiger, E., Walker, J. M. <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 Proteomics Protocols Handbook. , 571-607 (2005).</li><li>Wu, W. W. H., Sun, Y. H. B., Pant&#233;, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+import+of+influenza+A+viral+ribonucleoprotein+complexes+is+mediated+by+two+nuclear+localization+sequences+on+viral+nucleoprotein.">Nuclear import of influenza A viral ribonucleoprotein complexes is mediated by two nuclear localization sequences on viral nucleoprotein.</a> Virol J. 4, 49-49 (2007).</li><li>Babcock, H. P., Chen, C., Zhuang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+single-particle+tracking+to+study+nuclear+trafficking+of+viral+genes.">Using single-particle tracking to study nuclear trafficking of viral genes.</a> Biophys J. 87, 2749-2758 (2004).</li></ol>

La purification de vRNPs est basé sur la procédure décrite par Kemler et al. (1994). 1 Nous et les autres ont également utilisé ce protocole pour isoler vRNPs d&#39;étudier leur import nucléaire. 2,4,5 Nous recommandons l&#39;utilisation de la RNase conseils et des tubes lors de la manipulation vRNPs parce que le génome viral est constitué d&#39;ARN, et se dégrade donc facilement dans la présence d&#39;ARN. En outre, tous les tampons devraient être ...

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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>H3N2 X-31 A/AICHI/68 influenza A</td>
<td>&nbsp;</td>
<td>Charles River Laboratories</td>
<td>490715</td>
<td>&nbsp;</td>
<tr>
<td>Tris</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>T1503</td>
<td>&nbsp;</td>
<tr>
<td>MES</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M-8250</td>
<td>&nbsp;</td>
<tr>
<td>Glycerol</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>G33-1</td>
<td>&nbsp;</td>
<tr>
<td>Octylglucoside</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>O-8001</td>
<td>&nbsp;</td>
<tr>
<td>Lysolecithin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>L-4129</td>
<td>&nbsp;</td>
<tr>
<td>Dithiothreitol</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>D-9779</td>
<td>&nbsp;</td>
<tr>
<td>Coomassie brilliant blue G-250</td>
<td>&nbsp;</td>
<td>Kodak</td>
<td>1367796</td>
<td>&nbsp;</td>
<tr>
<td>diethyl pyrocarbonate (DEPC)-treated water</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>750024</td>
<td>&nbsp;</td>
<tr>
<td>Uranyl Acetate</td>
<td>&nbsp;</td>
<td>Ted Pella</td>
<td>19481</td>
<td>&nbsp;</td>
<tr>
<td>Ammonium Molybdate</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>A-674</td>
<td>&nbsp;</td>
<tr>
<td>Optima MAX-E Ultracentrifuge</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>434491</td>
<td>&nbsp;</td>
<tr>
<td>MLS-50 Rotor Package, Swinging Bucket</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>367280</td>
<td>&nbsp;</td>
<tr>
<td>TLA-120.2 Rotor Assembly, Fixed-Angle, Titanium</td>
<td>&nbsp;</td>
<td>Beckman Coulter</td>
<td>362046</td>
<td>&nbsp;</td>
<tr>
<td>Eppendorf Thermomixer</td>
<td>&nbsp;</td>
<td>Brinkman</td>
<td>022670000</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

purification and visualization of influenza a viral ribonucleoprotein complexes

La grippe A génome viral est constitué de huit sens négatif, simple brin des molécules d&#39;ARN, emballés individuellement avec des copies multiples de la grippe A nucléoprotéine (NP) en particules virales ribonulceoprotein (vRNPs). Le vRNPs la grippe sont enfermés dans l&#39;enveloppe virale. Lors de l&#39;entrée des cellules, cependant, ces complexes sont vRNP libéré dans le cytoplasme, où ils accéder à la machinerie de transport hôte nucléaire. Afin d&#39;étudier l&#39;import nucléaire de la grippe et le vRNPs la réplication du génome de la grippe, il est utile de travailler avec vRNPs isolés de telle sorte que les autres composantes du virus ne pas interférer avec ces processus. Ici, nous décrivons une procédure de purifier ces vRNPs du virus influenza A. La procédure débute par la perturbation de la grippe A virion avec des détergents afin de libérer les complexes vRNP du virion enveloppé. Le vRNPs sont ensuite séparées des autres composants de la grippe A virion sur un gradient discontinu de glycérol 33-70% par sédimentation de vitesse. Les fractions obtenues à partir du gradient de glycérol sont ensuite analysées via SDS-PAGE après coloration au bleu de Coomassie. Les fractions de pic contenant du NP sont ensuite rassemblées et concentrées par centrifugation. Après la concentration, l&#39;intégrité de la vRNPs est vérifiée par la visualisation de la vRNPs par microscopie électronique à transmission après coloration négative. La purification sur gradient de glycérol est une modification de celle du Kemler<em&gt; Et al.</em&gt; (1994)<sup&gt; 1</sup&gt;, Et la coloration négative a été réalisée par Wu<em&gt; Et al.</em&gt; (2007).<sup&gt; 2</sup

Watch this Scientific Journal Video about Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes at JoVE.com

Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes

Le génome du virus de la grippe A se compose de huit complexes séparés d&#39;ARN et de protéines, appelées complexes ribonucléoprotéiques virale (vRNPs). Ce document décrit la purification sur gradient de glycérol et de visualisation microscopie électronique en transmission de la grippe A vRNPs.

Purification et visualisation de la grippe A complexes ribonucléoprotéiques virale

The influenza A viral genome consists of eight negative-sense, single stranded RNA molecules, individually packed with multiple copies of the influenza A ...

purification-visualization-influenza-viral-ribonucleoprotein

Research

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Biology

12.9K vues.  University of British Columbia - UBC. Le génome du virus de la grippe A se compose de huit complexes séparés d'ARN et de protéines, appelées complexes ribonucléoprotéiques virale (vRNPs). Ce document décrit la purification sur gradient de glycérol et de visualisation microscopie électronique en transmission de la grippe A vRNPs.

Vidéo: Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staning of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compunds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

A short protocol for protein staining with Coomassie Brilliant Blue (CBB) G-250 in polyacrylamide gels is described without using organic solvents or acetic acid as in the classical staining procedures with CBB.

Coloration des protéines dans les gels de Coomassie G-250, sans solvant et l&#39;acide acétique organique

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

Recherche

Biologie

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging

Polyaminopolycarboxylate-based ligands are commonly used to chelate lanthanide ions, and the resulting complexes are 
useful as contrast agents for magnetic resonance imaging (MRI). Many commercially available ligands are especially useful because they contain 
functional groups that allow for fast, high-purity, and high-yielding conjugation to macromolecules and biomolecules via amine-reactive 
activated esters and isothiocyanate groups or thiol-reactive maleimides. While metalation of these ligands is considered common 
knowledge in the field of bioconjugation chemistry, subtle differences in metalation procedures must be taken into account when 
selecting metal starting materials. Furthermore, multiple options for purification and characterization exist, and selection of the most 
effective procedure partially depends on the selection of starting materials. These subtle differences are often neglected in published 
protocols. Here, our goal is to demonstrate common methods for metalation, purification, and characterization of lanthanide complexes 
that can be used as contrast agents for MRI (Figure 1). We expect that this publication will enable biomedical scientists to incorporate 
lanthanide complexation reactions into their repertoire of commonly used reactions by easing the selection of starting materials and 
purification methods.

We demonstrate the metalation, purification, and characterization of lanthanide complexes. The complexes described here can be conjugated to macromolecules to enable tracking of these molecules using magnetic resonance imaging.

Préparation, la purification et la caractérisation des complexes de lanthanides pour utilisation comme agents de contraste pour imagerie par résonance magnétique

Polyaminopolycarboxylate-based ligands are commonly used to chelate lanthanide ions, and the resulting complexes are 
useful as contrast agents for ...

Purification of Hsp104, a Protein Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key selective advantages. First, renaturation of disordered aggregates by Hsp104 empowers yeast survival after various protein-misfolding stresses, including heat shock3,5,11,12. Second, remodeling of cross-beta amyloid fibrils by Hsp104 enables yeast to exploit myriad prions (infectious amyloids) as a reservoir of beneficial and heritable phenotypic variation13-22. Remarkably, Hsp104 directly remodels preamyloid oligomers and amyloid fibrils, including those comprised of the yeast prion proteins Sup35 and Ure223-30. This amyloid-remodeling functionality is a specialized facet of yeast Hsp104. The E. coli orthologue, ClpB, fails to remodel preamyloid oligomers or amyloid fibrils26,31,32.
Hsp104 orthologues are found in all kingdoms of life except, perplexingly, animals. Indeed, whether animal cells possess any enzymatic system that couples protein disaggregation to renaturation (rather than degradation) remains unknown33-35. Thus, we and others have proposed that Hsp104 might be developed as a therapeutic agent for various neurodegenerative diseases connected with the misfolding of specific proteins into toxic preamyloid oligomers and amyloid fibrils4,7,23,36-38. There are no treatments that directly target the aggregated species associated with these diseases. Yet, Hsp104 dissolves toxic oligomers and amyloid fibrils composed of alpha-synuclein, which are connected with Parkinson's Disease23 as well as amyloid forms of PrP39. Importantly, Hsp104 reduces protein aggregation and ameliorates neurodegeneration in rodent models of Parkinson's Disease23 and Huntington's disease38. Ideally, to optimize therapy and minimize side effects, Hsp104 would be engineered and potentiated to selectively remodel specific aggregates central to the disease in question4,7. However, the limited structural and mechanistic understanding of how Hsp104 disaggregates such a diverse repertoire of aggregated structures and unrelated proteins frustrates these endeavors30,40-42.
To understand the structure and mechanism of Hsp104, it is essential to study the pure protein and reconstitute its disaggregase activity with minimal components. Hsp104 is a 102kDa protein with a pI of ~5.3, which hexamerizes in the presence of ADP or ATP, or at high protein concentrations in the absence of nucleotide43-46. Here, we describe an optimized protocol for the purification of highly active, stable Hsp104 from E. coli. The use of E. coli allows simplified large-scale production and our method can be performed quickly and reliably for numerous Hsp104 variants. Our protocol increases Hsp104 purity and simplifies His6-tag removal compared to a previous purification method from E. coli47. Moreover, our protocol is more facile and convenient than two more recent protocols26,48.

Here, we describe a protocol for the purification of highly active Hsp104, a hexameric AAA+ protein from yeast, which couples ATP hydrolysis to protein disaggregation. This scheme exploits a His6-tagged construct for affinity purification from E. coli followed by anion-exchange chromatography, His6-tag removal with TEV protease, and size-exclusion chromatography.

Purification de Hsp104, une protéine Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key ...

Chromatographic Purification of Highly Active Yeast Ribosomes

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers. Particularly troublesome is the fact that lysis of cells releases a large number of proteases and nucleases which can degrade ribosomes. Thus, it is important to separate ribosomes from these enzymes as quickly as possible. Unfortunately, conventional differential ultracentrifugation methods leaves ribosomes exposed to these enzymes for unacceptably long periods of time, impacting their structural integrity and functionality. To address this problem, we utilize a chromatographic method using a cysteine charged Sulfolink resin. This simple and rapid application significantly reduces co-purifying proteolytic and nucleolytic activities, producing high yields of intact, highly biochemically active yeast ribosomes. We suggest that this method should also be applicable to mammalian ribosomes. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

Contamination of preparations of eukaryotic ribosomes purified by traditional methods by co-purifying nucleases and proteases negatively impacts on downstream biochemical and structural analyses. A rapid and simple chromatographic purification method is used to solve this problem using yeast ribosomes as a model system.

Purification chromatographique des ribosomes de levure hautement active

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers.  ...

Method for the Isolation and Identification of mRNAs, microRNAs and Protein Components of Ribonucleoprotein Complexes from Cell Extracts using RIP-Chip

As a result of the development of high-throughput sequencing and efficient microarray analysis, global gene expression analysis has become an easy and readily available form of data collection. In many research and disease models however, steady state levels of target gene mRNA does not always directly correlate with steady state protein levels. Post-transcriptional gene regulation is a likely explanation of the divergence between the two. Driven by the binding of RNA Binding Proteins (RBP), post-transcriptional regulation affects mRNA localization, stability and translation by forming a Ribonucleoprotein (RNP) complex with target mRNAs. Identifying these unknown de novo mRNA targets from cellular extracts in the RNP complex is pivotal to understanding mechanisms and functions of the RBP and their resulting effect on protein output. This protocol outlines a method termed RNP immunoprecipitation-microarray (RIP-Chip), which allows for the identification of specific mRNAs associated in the ribonucleoprotein complex, under changing experimental conditions, along with options to further optimize an experiment for the individual researcher. With this important experimental tool, researchers can explore the intricate mechanisms associated with post-transcriptional gene regulation as well as other ribonucleoprotein interactions.

A step by step protocol to isolating and identifying RNA associated complexes through RIP-Chip.

Méthode pour l&#39;isolement et l&#39;identification des ARNm, les microARN et composants protéiques des complexes ribonucléoprotéiques partir d&#39;extraits cellulaires utilisant RIP-Chip

As a result of the development of high-throughput sequencing and efficient microarray analysis, global gene expression analysis has become an easy and ...

Identification of Protein Complexes in Escherichia coli using Sequential Peptide Affinity Purification in Combination with Tandem Mass Spectrometry

Since most cellular processes are mediated by macromolecular assemblies, the systematic identification of protein-protein interactions (PPI) and the identification of the subunit composition of multi-protein complexes can provide insight into gene function and enhance understanding of biological systems1, 2. Physical interactions can be mapped with high confidence vialarge-scale isolation and characterization of endogenous protein complexes under near-physiological conditions based on affinity purification of chromosomally-tagged proteins in combination with mass spectrometry (APMS). This approach has been successfully applied in evolutionarily diverse organisms, including yeast, flies, worms, mammalian cells, and bacteria1-6. In particular, we have generated a carboxy-terminal Sequential Peptide Affinity (SPA) dual tagging system for affinity-purifying native protein complexes from cultured gram-negative Escherichia coli, using genetically-tractable host laboratory strains that are well-suited for genome-wide investigations of the fundamental biology and conserved processes of prokaryotes1, 2, 7. Our SPA-tagging system is analogous to the tandem affinity purification method developed originally for yeast8, 9, and consists of a calmodulin binding peptide (CBP) followed by the cleavage site for the highly specific tobacco etch virus (TEV) protease and three copies of the FLAG epitope (3X FLAG), allowing for two consecutive rounds of affinity enrichment. After cassette amplification, sequence-specific linear PCR products encoding the SPA-tag and a selectable marker are integrated and expressed in frame as carboxy-terminal fusions in a DY330 background that is induced to transiently express a highly efficient heterologous bacteriophage lambda recombination system10. Subsequent dual-step purification using calmodulin and anti-FLAG affinity beads enables the highly selective and efficient recovery of even low abundance protein complexes from large-scale cultures. Tandem mass spectrometry is then used to identify the stably co-purifying proteins with high sensitivity (low nanogram detection limits).
Here, we describe detailed step-by-step procedures we commonly use for systematic protein tagging, purification and mass spectrometry-based analysis of soluble protein complexes from E. coli, which can be scaled up and potentially tailored to other bacterial species, including certain opportunistic pathogens that are amenable to recombineering. The resulting physical interactions can often reveal interesting unexpected components and connections suggesting novel mechanistic links. Integration of the PPI data with alternate molecular association data such as genetic (gene-gene) interactions and genomic-context (GC) predictions can facilitate elucidation of the global molecular organization of multi-protein complexes within biological pathways. The networks generated for E. coli can be used to gain insight into the functional architecture of orthologous gene products in other microbes for which functional annotations are currently lacking.

Identification of Protein Complexes in Escherichia coli using Sequential Peptide Affinity Purification in Combination with Tandem Mass Spectrometry

Affinity purification of tagged proteins in combination with mass spectrometry (APMS) is a powerful method for the systematic mapping of protein interaction networks and for investigating the mechanistic basis of biological processes. Here, we describe an optimized sequential peptide affinity (SPA) APMS procedure developed for the bacterium Escherichia coli that can be used to isolate and characterize stable multi-protein complexes to near homogeneity even starting from low copy numbers per cell.

Identification des complexes protéiques dans<em&gt; Escherichia coli</em&gt; En utilisant séquentielle Purification par affinité peptide en combinaison avec la spectrométrie de masse en tandem

Since most cellular processes are mediated by macromolecular assemblies, the systematic identification of protein-protein interactions (PPI) and the ...

AFM-based Mapping of the Elastic Properties of Cell Walls: at Tissue, Cellular, and Subcellular Resolutions

We describe a recently developed method to measure mechanical properties of the surfaces of plant tissues using atomic force microscopy (AFM) micro/nano-indentations, for a JPK&#160;AFM. Specifically, in this protocol we measure the apparent Young&#8217;s modulus of cell walls at subcellular resolutions across regions of up to 100 &#181;m&#160;x 100 &#181;m in floral meristems, hypocotyls, and roots. This requires careful preparation of the sample, the correct selection of micro-indenters and indentation depths. To account for cell wall properties only, measurements are performed in highly concentrated solutions of mannitol in order to plasmolyze the cells and thus remove the contribution of cell turgor pressure.
In contrast to other extant techniques, by using different indenters and indentation depths, this method allows simultaneous multiscale measurements, i.e. at subcellular resolutions and across hundreds of cells comprising a tissue. This means that it is now possible&#160;to spatially-temporally characterize the changes that take place in the mechanical properties of cell walls during development, enabling these changes to be correlated with growth and differentiation. This represents a key step to understand how coordinated microscopic cellular changes bring about macroscopic morphogenetic events.
However, several limitations remain: the method can only be used on fairly small samples (around 100 &#181;m in diameter) and only on external tissues; the method is sensitive to tissue topography; it measures only certain aspects of the tissue&#8217;s complex mechanical properties. The technique is being developed rapidly and it is likely that most of these limitations will be resolved in the near future.

We describe a method to map mechanical properties of plant tissues using an atomic force microscope (AFM). We focus on how to record mechanical changes that take place in cell walls during plant development at wide-field mesoscale, enabling these changes to be correlated with growth and morphogenesis.

La cartographie sur-AFM des propriétés élastiques de la paroi cellulaire: au tissu, cellulaire, et des résolutions Subcellular

We describe a recently developed method to measure mechanical properties of the surfaces of plant tissues using atomic force microscopy (AFM) ...

Rapid Isolation And Purification Of Mitochondria For Transplantation By Tissue Dissociation And Differential Filtration

Previously described mitochondrial isolation methods using differential centrifugation and/or Ficoll gradient centrifugation require 60 to 100 min to complete. We describe a method for the rapid isolation of mitochondria from mammalian biopsies using a commercial tissue dissociator and differential filtration. In this protocol, manual homogenization is replaced with the tissue dissociator&#8217;s standardized homogenization cycle. This allows for uniform and consistent homogenization of tissue that is not easily achieved with manual homogenization. Following tissue dissociation, the homogenate is filtered through nylon mesh filters, which eliminate repetitive centrifugation steps. As a result, mitochondrial isolation can be performed in less than 30 min. This isolation protocol yields approximately 2 x 1010 viable and respiration competent mitochondria from 0.18 &#177; 0.04 g (wet weight) tissue sample.

A method for rapid isolation of mitochondria from mammalian tissue biopsies is described. Rat liver or skeletal muscle preparations were homogenized with a commercial tissue dissociator and mitochondria were isolated by differential filtration through nylon mesh filters. Mitochondrial isolation time is &#60;30 min compared to 60 - 100 min using alternative methods.

Isolement rapide et la purification des mitochondries pour la transplantation par la dissociation des tissus et différencié Filtration

Previously described mitochondrial isolation methods using differential centrifugation and/or Ficoll gradient centrifugation require 60 to 100 min to ...

Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes

INO80 chromatin remodeling complexes regulate nucleosome dynamics and DNA accessibility by catalyzing ATP-dependent nucleosome remodeling. Human INO80 complexes consist of 14 protein subunits including Ino80, a SNF2-like ATPase, which serves both as the catalytic subunit and the scaffold for assembly of the complexes. Functions of the other subunits and the mechanisms by which they contribute to the INO80 complex&#39;s chromatin remodeling activity remain poorly understood, in part due to the challenge of generating INO80 subassemblies in human cells or heterologous expression systems. This JOVE protocol describes a procedure that allows purification of human INO80 chromatin remodeling subcomplexes that are lacking a subunit or a subset of subunits. N-terminally FLAG epitope tagged Ino80 cDNA are stably introduced into human embryonic kidney (HEK) 293 cell lines using Flp-mediated recombination. In the event that a subset of subunits of the INO80 complex is to be deleted, one expresses instead mutant Ino80 proteins that lack the platform needed for assembly of those subunits. In the event an individual subunit is to be depleted, one transfects siRNAs targeting this subunit into an HEK 293 cell line stably expressing FLAG tagged Ino80 ATPase. Nuclear extracts are prepared, and FLAG immunoprecipitation is performed to enrich protein fractions containing Ino80 derivatives. The compositions of purified INO80 subcomplexes can then be analyzed using methods such as immunoblotting, silver staining, and mass spectrometry. The INO80 and INO80 subcomplexes generated according to this protocol can be further analyzed using various biochemical assays, which are described in the accompanying JOVE protocol. The methods described here can be adapted for studies of the structural and functional properties of any mammalian multi-subunit chromatin remodeling and modifying complexes.

This protocol describes a procedure for generating and purifying wild type and mutant versions of the human INO80 chromatin remodeling complex. Epitope tagged versions of INO80 subunits are stably expressed in HEK293 cells, and complete complexes and complexes lacking specific sets of subunits are purified by immunoaffinity chromatography.

Production et purification des droits de INO80 remodelage de la chromatine Complexes et Subcomplexes

INO80 chromatin remodeling complexes regulate nucleosome dynamics and DNA accessibility by catalyzing ATP-dependent nucleosome remodeling. Human INO80 ...

Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the Nucleoskeleton and Cytoskeleton (LINC complexes). These protein scaffolds span the nuclear envelope and connect the interior of the nucleus to components of the surrounding cytoplasmic cytoskeleton. LINC complexes consist of two evolutionary-conserved protein families, Sun proteins and Nesprins that harbor C-terminal molecular signature motifs called the SUN and KASH domains, respectively. Sun proteins are transmembrane proteins of the inner nuclear membrane whose N-terminal nucleoplasmic domain interacts with the nuclear lamina while their C-terminal SUN domains protrudes into the perinuclear space and interacts with the KASH domain of Nesprins. Canonical Nesprin isoforms have a variable sized N-terminus that projects into the cytoplasm and interacts with components of the cytoskeleton. This protocol describes the validation of a dominant-negative transgenic mouse strategy that disrupts endogenous SUN/KASH interactions in a cell-type specific manner. Our approach is based on the Cre/Lox system that bypasses many drawbacks such as perinatal lethality and cell nonautonomous phenotypes that are associated with germline models of LINC complex inactivation. For this reason, this model provides a useful tool to understand the role of LINC complexes during development and homeostasis in a wide array of tissues.

Nuclear envelope proteins play a central role in many basic biological processes and have been implicated in a variety of human diseases. This protocol describes a new Cre/Lox-based mouse model that allows for the spatiotemporal control of LINC complexes disruption.

Validation d&#39;un modèle de souris de perturber CLIC complexes de façon spécifique à la cellule

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the ...