Whitehead Institute Fellows Funds

Teil 1: Einrichten der Infektion <ol><li> Wachsen HeLa-Zellen in Flaschen und warten, bis die Zellen ca. 80% konfluent sind. </li><li> Bereiten Sie genug virale Nährboden für das Experiment: regelmäßige DMEM mit 2% FBS und ohne Zusatz von Antibiotika. </li><li> Die Infektion kann entweder mit einer groben Bestand von Vaccinia-Virus mit einem bekannten Titer, oder Saccharose gereinigten Virus mit einem bekannten Titer, wenn Sie über Host-Genexpression sind besorgt durchgeführt werden. </li><li> Wenn Sie mit Saccharose gereinigte Virus sind, gehen Sie direkt zu Teil 2. </li><li> Wenn Sie eine grobe Vaccinia-Virus Lager sind, unmittelbar vor der Infektion, beschallen ein Aliquot des Virus in eine Tasse Sonicator mit einem Bad aus hauptsächlich aus Eis und wenig Wasser. <ul style="list-style-type:lower-alpha;"><li> Ultraschallbad bei ca. 30W für 20 Sekunden. </li><li> Vortex die Röhre, und wiederholen Sie die Beschallung 3 mal, indem mehr Eis, wenn nötig, den Kelch mit Eis gekühlt und verpackt zu halten. </li><li> Vortex zwischen den einzelnen Beschallung Schritt. </li><li> Fahren Sie mit Teil 2. </li></ul></li><li> Alternativ, wenn Sie nicht über eine Tasse Sonicator, mischen das gleiche Volumen des rohen Virus Lager und 0.25mg/mL Trypsin. <ul style="list-style-type:lower-alpha;"><li> Vortex kräftig. </li><li> Inkubieren des Virus Lager / Trypsin-Mix in einem 37 ° C im Wasserbad für 30 Minuten. </li><li> Vortex bei 5-10 Minuten-Takt. </li><li> Fahren Sie mit Teil 2. </li></ul></li></ol> Teil 2: Infektion der Zellen <ol><li> Berechnen Sie die Menge von Viruspartikeln benötigt, um die Monoschicht an der gewünschten Multiplizität der Infektion (MOI) zu infizieren. Typischerweise wird ein hohes Trägheitsmoment (zwischen 5 und 10) für eine Infektion timecourses verwendet. </li><li> Fügen Sie die gewünschte Menge an Saccharose gereinigten Virus oder trypsiniert Rohöl-Virus auf 37 ° C virale Wachstum Medien und gut mischen. Sie sollten genügend Medien gerade bedeckt den Boden des Kolbens. Zum Beispiel, 10 ml Medium für eine T-175 Kolben. </li><li> Entfernen Sie das Medium von den Zellen und gründlich mit Raumtemperatur PBS. </li><li> Fügen Sie die Virus / virale Wachstum Medien in jeden Kolben. <ul style="list-style-type:lower-alpha;"><li> Vorsichtig schwenken, neigen Platten und Inkubation bei 37 ° C in einer 5% igen CO2-Inkubator für 1 Stunde. </li><li> Tilt und wirbeln Platten alle 15 Minuten, um Viren gleichmäßig verteilt und halten Zellen feucht. </li><li> Für eine 0hr/Mock Zeitpunkt, fügen Sie das virale Wachstum Medien nur mit kein Virus hinzugefügt. </li></ul></li><li> Nach dem 1 Stunde Inkubation, entfernen Sie die Medien mit dem Virus, und spülen Sie dreimal mit PBS Raumtemperatur. </li><li> Fügen Sie die maximale Menge des viralen Wachstums-Medium pro Flasche. Zum Beispiel, 30 mL der Medien für eine T-175 Kolben. Starten Sie das Zählen diese als 0 Std. Zeitpunkt. </li></ol> Teil 3: Ernten von Zellen <ol><li> Überprüfen Sie die Zellen unter dem Mikroskop und achten Sie auf zytopathischen Effekt (CPE). </li><li> Entfernen Sie die Medien und spülen Zellen mit 30 ml Raumtemperatur PBS. </li><li> 15 ml Trypsin zu den Zellen und inkubieren für 2-5min bei 37 ° C. </li><li> Überprüfen Sie unter Mikroskop für Zellablösung und tippen Kolben vorsichtig, um Zellen zu entfernen. </li><li> Transfer-Zellen mit einer sterilen serologischen Pipette in ein konisches 50 ml-Tube. </li><li> Waschen Sie die Flasche mit dem gleichen Volumen des Zellwachstums Medien, und fügen Sie die Medien auf die Trypsin-Zellen in den konischen Rohr. </li><li> Zentrifugieren Sie die Zellen bei 300 x g für 5 Minuten bei Raumtemperatur. </li><li> Entfernen Sie die Trypsin / Medien aus dem Zellpellet. </li><li> Zellpellet entweder in Trizolreagenz oder der Lysepuffer aus Ihrer gewünschten RNA Isolation Kit. </li><li> Wenn Sie TRIzol sind, teilen Sie die Probe in 1 ml Aliquots in 1,5 ml Eppendorf-Röhrchen beschriftet und frieren bei -80 ° C. </li><li> Wiederholen Sie dies für alle Zeitpunkte, die Ernte ein Kolben pro Zeitpunkt. </li></ol> Teil 4: RNA-Extraktion der Proben in TRIzol <ol><li> An diesem Punkt sollten Sie Ihre Proben in Trizolreagenz resuspendiert werden und bereit, verarbeitet werden. </li><li> Add 200 ul der BCP Phasentrennung Reagenz für alle 1 ml Trizol in jeder Röhre. Möglicherweise müssen Sie die Probe auf ein größeres Rohr übertragen, wenn Sie beginnen mit einer großen Menge von TRIzol. </li><li> Vortex oder kräftig schütteln und Inkubieren bei Raumtemperatur für 2-3 Minuten. </li><li> Zentrifugieren Sie die Probe bei 12.000 xg für 15 Minuten. </li><li> Übertragen Sie die wässrige Phase in ein frisches Röhrchen. Die wässrige Phase wird die klare Schicht auf der Oberseite. Sie sollten sich erholen rund 600μL für jeden 1ml von TRIzol Sie begann mit. </li><li> Haben ein zweites Phenol / Chloroform-Extraktion, diesmal mit 500μL Chloroform pro 1 ml TRIzol, anstelle von BCP. </li><li> Vortex oder kräftig schütteln und Inkubieren bei Raumtemperatur für 2-3 Minuten. </li><li> Zentrifugieren Sie die Probe bei 12.000 xg für 15 Minuten. </li><li> Übertragen Sie die wässrige Phase in ein frisches Röhrchen. Die wässrige Phase wird die klare Schicht auf der Oberseite. </li><li> Add 20mg von linearen Acrylamid zu jeder Probe. Die lineare Acrylamid wirkt als Träger und hilft bei der Fällung der RNA. </li><li> Add 500 &amp; micro; L Isopropanol pro 1 ml TRIzol Sie begann mit jeder Probe und gut mischen. </li><li> Inkubieren Proben bei Raumtemperatur für 10 Minuten. </li><li> Zentrifuge in einer Mikrozentrifuge bei maximaler Geschwindigkeit für 10-15 Minuten. </li><li> Das RNA-Pellet wird sichtbar am Boden des Röhrchens. Ganz vorsichtig den Überstand aus der Tube, entweder mit einem Staubsauger Sauger, oder manuell durch Pipette. Bitte nicht stören das Pellet. </li><li> Waschen des Pellets mit 1 ml 70% Ethanol. <ul style="list-style-type:lower-alpha;"><li> 1 ml 70% Ethanol zum Pellet. </li><li> Zentrifuge mit hoher Geschwindigkeit 14.000 g für 5-7 Minuten. </li><li> Sehr vorsichtig, nehmen Sie die Ethanol aus der Tube, entweder mit einem Staubsauger Sauger, oder manuell durch Pipette. Prüfen Sie, ob das Pellet sichtbar am Boden des Röhrchens wird. </li><li> Überstand verwerfen. </li></ul></li><li> Wiederholen Sie den Waschvorgang. Nachdem der Überstand wird verworfen, markieren, wo Pellet wird auf das Rohr. </li><li> Der Luft trocknen lassen Pellet nicht länger als 5 Minuten. Nicht übertrocknen oder der RNA wird schwierig sein, zu rekonstruieren! </li><li> Wenn Sie den optionalen DNase-Behandlung folgen, um alle verbleibenden DNA aus der Probe entfernt werden soll, das Pellet in 17μL von Nuklease-freies Wasser. Ansonsten das Pellet in 20 &amp;mgr; l von Nuklease-freies Wasser und weiterhin Schritt 22 fort. </li><li> (Optional DNase-Behandlung) mit dem Qiagen RNase-freie DNase Set, fügen 2μL Buffer RDD und 1μL rekonstituierte RNase-freie DNase I auf der resuspendierten RNA. Vorsichtig mischen. </li><li> (Optional DNase-Behandlung) bei 37 ° C für 30 Minuten. </li><li> (Optional DNase-Behandlung) hinzufügen 2μL von 2,5 mM EDTA und Inkubation bei 65 ° C für 5 Minuten, um die DNase zu inaktivieren. Überschreiten Sie nicht die Inaktivierung der Zeit oder Temperatur längere Zeit / höhere Temperaturen Abbau der RNA führen kann. </li><li> Überprüfen Sie die RNA-Konzentration von Spektralphotometer. </li><li> Bewahren Sie die RNA-Probe bei -80 ° C. </li><li> (Optional QC) Überprüfen Sie die RNA-Qualität mittels eines Agilent BioAnalyzer, oder indem Sie die Probe auf einem denaturierenden Gel und die Kontrolle der OD. (260nm und 260/280 Ratio) </li></ol>

<ol>
	<li>KH, R. u. b. i. n. s., LE, H. e. n. s. l. e. y., GW, B. e. l. l., Wang, C., EJ, L. e. f. k. o. w. i. t. z., PO, B. r. o. w. n., DA, R. e. l. m. a. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analysis+of+viral+gene+expression+programs+during+poxvirus+infection:+a+transcriptional+map+of+the+vaccinia+and+monkeypox+genomes.">Comparative analysis of viral gene expression programs during poxvirus infection: a transcriptional map of the vaccinia and monkeypox genomes.</a> PLoS ONE. 3 (7), e2628-e2628 (2008).</li><li>Assarsson, E., Greenbaum, J. A., Sundstr&#246;m, M., Schaffer, L., Hammond, J. A., Pasquetto, V., Oseroff, C., Hendrickson, R. C., Lefkowitz, E. J., Tscharke, D. C., Sidney, J., Grey, H. M., Head, S. R., Peters, B., Sette, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+analysis+of+a+complete+poxvirus+transcriptome+reveals+an+immediate-early+class+of+genes.">Kinetic analysis of a complete poxvirus transcriptome reveals an immediate-early class of genes.</a> Proc. Natl. Acad. Sci. 105 (6), 2140-2145 (2008).</li><li>Satheshkumar, P. S., Moss, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poxvirus+transcriptome+analysis.">Poxvirus transcriptome analysis.</a> Proc. Natl. Acad. Sci. U.S.A. 105, E62-E62 (2008).</li><li>Assarsson, E., Greenbaum, J. A., Sundstr&#246;m, M., Schaffer, L., Hammond, J. A., Pasquetto, V., Oseroff, C., Hendrickson, R. C., Lefkowitz, E. J., Tscharke, D. C., Sidney, J., Grey, H. M., Head, S. R., Peters, B., Sette, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A.+Reply+to+Satheshkumar+and+Moss:+Poxvirus+transcriptome+analysis.">A. Reply to Satheshkumar and Moss: Poxvirus transcriptome analysis.</a> Proc. Natl. Acad. Sci. U.S.A. 105, E63-E64 (2008).</li><li>Guerra, S., L&#243;pez-Fern&#225;ndez, L. A., Pascual-Montano, A., Mu&#241;oz, M., Harshman, K., Esteban, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+gene+expression+survey+of+vaccinia+virus+infection+of+human+HeLa+cells.">Cellular gene expression survey of vaccinia virus infection of human HeLa cells.</a> J Virol. 77 (11), 6493-6506 (2003).</li><li>Guerra, S., L&#243;pez-Fern&#225;ndez, L. A., Conde, R., Pascual-Montano, A., Harshman, K., Esteban, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microarray+analysis+reveals+characteristic+changes+of+host+cell+gene+expression+in+response+to+attenuated+modified+vaccinia+virus+Ankara+infection+of+human+HeLa+cells.">Microarray analysis reveals characteristic changes of host cell gene expression in response to attenuated modified vaccinia virus Ankara infection of human HeLa cells.</a> J Virol. 78 (11), 5820-5824 (2004).</li><li>Guerra, S., L&#243;pez-Fern&#225;ndez, L. A., Pascual-Montano, A., N&#225;jera, J. L., Zaballos, A., Esteban, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host+response+to+the+attenuated+poxvirus+vector+NYVAC:+upregulation+of+apoptotic+genes+and+NF-kappaB-responsive+genes+in+infected+HeLa+cells.">Host response to the attenuated poxvirus vector NYVAC: upregulation of apoptotic genes and NF-kappaB-responsive genes in infected HeLa cells.</a> J Virol. 80 (2), 985-998 (2006).</li><li>Guerra, S., N&#225;jera, J. L., Gonz&#225;lez, J. M., L&#243;pez-Fern&#225;ndez, L. A., Climent, N., JM, G. a. t. e. l. l., Gallart, T., Esteban, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+gene+expression+profiling+after+infection+of+immature+human+monocyte-derived+dendritic+cells+by+the+attenuated+poxvirus+vectors+MVA+and+NYVAC.">Distinct gene expression profiling after infection of immature human monocyte-derived dendritic cells by the attenuated poxvirus vectors MVA and NYVAC.</a> 81 (16), 8707-8721 (2007).</li></ol>

Kritische Schritte Part 1 &amp; 2 Es gibt mehrere wichtige Schritte zum Aufbau einer synchronen Vaccinia-Infektion, wobei die erste sorgfältige Ultraschall (oder trypzinizing) des Virus, um Viruspartikel aufzuschlüsseln. Vaccinia ist sehr anfällig für Aggregation, und die Störung der Viruspartikel ist dafür auch die Infektion der Zellen wichtig. Um eine synchrone Infektion zu erreichen, sollte ein hohes MOI (größer als 2) verwendet werden, um sicherzustellen, ...

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		<th>Comment</th>
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<td>TRIzol Reagent</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>15596-026</td>
<td>Similar reagents, such as TriPure from Roche, will also work.</td>
</tr>
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<td>BCP Phase Separation Reagent</td>
<td>Reagent</td>
<td>Molecular Research Center</td>
<td>BP151</td>
<td>&nbsp;</td>
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<td>RNase-Free DNase Set</td>
<td>Reagent</td>
<td>Qiagen</td>
<td>79254</td>
<td>DNase treatment is an optional step.</td>
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vaccinia virus infection &amp; temporal analysis of virus gene expression: part 1

Die Familie<em&gt; Poxviridae</em&gt; Besteht aus großen doppelsträngigen DNA-Viren enthalten, die ausschließlich im Zytoplasma der infizierten Zellen replizieren. Die Mitglieder des<em&gt; Orthopox</em&gt; Gattung gehören Variola, dem Erreger der menschlichen Pocken, Affenpocken und Vaccinia (VAC), der prototypische Mitglied der Virus-Familie. Innerhalb der relativ groß (~ 200 kb) Vaccinia-Genom gibt drei Klassen von Genen kodiert: frühe, mittlere und spät. Während alle drei Klassen von viral-kodierten RNA-Polymerasen transkribiert werden, dient jede Klasse eine andere Funktion im Lebenszyklus des Virus. Pockenviren nutzen mehrere Strategien zur Modulation der zellulären Umgebung Host während der Infektion. Um Regulierung der Wirt und Virus Genexpression verstehen, müssen wir genomweite Ansätze genutzt werden, um Transkript Fülle von beiden Viren und Wirtszellen zu analysieren. Hier zeigen wir, zeitlicher Verlauf Infektionen von HeLa-Zellen mit Vaccinia-Virus und Sampling-RNA zu verschiedenen Zeitpunkten nach der Infektion. Beide Gastgeber und virale RNA isoliert und verstärkt für die Hybridisierung an Microarrays zur Analyse der Genexpression.

Watch this Scientific Journal Video about Vaccinia Virus Infection & Temporal Analysis of Virus Gene Expression: Part 1 at JoVE.com

Vaccinia Virus Infection &amp; Temporal Analysis of Virus Gene Expression: Part 1

Protokoll zur Vaccinia-Infektion von HeLa-Zellen und die Analyse von Host-und virale Genexpression.

Vaccinia Virus Infection &amp; Temporal Analysis des Virus Gene Expression: Teil 1

The family Poxviridae consists of large double-stranded DNA containing viruses that replicate exclusively in the cytoplasm of infected cells.  Members of ...

vaccinia-virus-infection-temporal-analysis-virus-gene-expression-part

Research

JoVE Journal

Biology

10.2K Aufrufe.  MIT - Massachusetts Institute of Technology. Protokoll zur Vaccinia-Infektion von HeLa-Zellen und die Analyse von Host-und virale Genexpression.

Serie: Vaccinia Virus Infection & Temporal Analysis of Virus Gene Expression: Part 1

Bacterial Gene Expression Analysis Using Microarrays

Bakterielle Gene Expression Analysis Using Microarrays

Forschung

Biologie

The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell  electroporation system and Gene Pulser  electroporation buffer were specifically developed to transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells.This video demonstrates how to establish primary hematopoietic cell cultures from murine bone marrow, and then prepare them for electroporation in the MXcell system. We begin by isolating femur and tibia. Bone marrow from both femur and tibia are then harvested and cultures are established. Cultured bone marrow cells are then transfected and analyzed.

This procedure describes how to establish primary hematopoietic cell cultures from murine bone marrow and is followed by transfection using the Gene Pulser MXCell electroporation system.

Die Herstellung von primären hämatopoetischen Zellkulturen aus Knochenmark der Maus für die Elektroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

Vaccinia Virus Infection &amp; Temporal Analysis of Virus Gene Expression: Part 2

The family Poxviridae consists of large double-stranded DNA containing viruses that replicate exclusively in the cytoplasm of infected cells. Members of the orthopox genus include variola, the causative agent of human small pox, monkeypox, and vaccinia (VAC), the prototypic member of the virus family. Within the relatively large (~ 200 kb) vaccinia genome, three classes of genes are encoded: early, intermediate, and late. While all three classes are transcribed by virally-encoded RNA polymerases, each class serves a different function in the life cycle of the virus. Poxviruses utilize multiple strategies for modulation of the host cellular environment during infection. In order to understand regulation of both host and virus gene expression, we have utilized genome-wide approaches to analyze transcript abundance from both virus and host cells. Here, we demonstrate time course infections of HeLa cells with Vaccinia virus and sampling RNA at several time points post-infection. Both host and viral total RNA is isolated and amplified for hybridization to microarrays for analysis of gene expression.

Protocol for Vaccinia infection of HeLa cells and analysis of host and viral gene expression. Part 2 of 3.

Vaccinia Virus Infection &amp; Temporal Analysis des Virus Gene Expression: Teil 2

Vaccinia Virus Infection &amp; Temporal Analysis of Virus Gene Expression: Part 3

The family Poxviridae consists of large double-stranded DNA containing viruses that replicate exclusively in the cytoplasm of infected cells. Members of the orthopox genus include variola, the causative agent of human small pox, monkeypox, and vaccinia (VAC), the prototypic member of the virus family. Within the relatively large (~ 200 kb) vaccinia genome, three classes of genes are encoded: early, intermediate, and late. While all three classes are transcribed by virally-encoded RNA polymerases, each class serves a different function in the life cycle of the virus. Poxviruses utilize multiple strategies for modulation of the host cellular environment during infection. In order to understand regulation of both host and virus gene expression, we have utilized genome-wide approaches to analyze transcript abundance from both virus and host cells. Here, we demonstrate time course infections of HeLa cells with Vaccinia virus and sampling RNA at several time points post-infection. Both host and viral total RNA is isolated and amplified for hybridization to microarrays for analysis of gene expression.

Protocol for Vaccinia infection of HeLa cells and analysis of host and viral gene expression. Part 3 describes the process of fluorescently labeling the amplified RNA from both host and viral samples by amino allyl coupling of dyes. Part 3 of 3.

Vaccinia Virus Infection &amp; Temporal Analysis des Virus Gene Expression: Teil 3

Virus-induced Gene Silencing (VIGS) in Nicotiana benthamiana and Tomato

RNA interference (RNAi) is a highly specific gene-silencing phenomenon triggered by dsRNA1. This silencing mechanism uses two major classes of RNA regulators: microRNAs, which are produced from non-protein coding genes and short interfering RNAs (siRNAs). Plants use RNAi to control transposons and to exert tight control over developmental processes such as flower organ formation and leaf development2,3,4. Plants also use RNAi to defend themselves against infection by viruses. Consequently, many viruses have evolved suppressors of gene silencing to allow their successful colonization of their host5.
Virus-induced gene silencing (VIGS) is a method that takes advantage of the plant RNAi-mediated antiviral defense mechanism. In plants infected with unmodified viruses the mechanism is specifically targeted against the viral genome. However, with virus vectors carrying sequences derived from host genes, the process can be additionally targeted against the corresponding host mRNAs. VIGS has been adapted for high-throughput functional genomics in plants by using the plant pathogen Agrobacterium tumefaciens to deliver, via its Ti plasmid, a recombinant virus carrying the entire or part of the gene sequence targeted for silencing. Systemic virus spread and the endogenous plant RNAi machinery take care of the rest. dsRNAs corresponding to the target gene are produced and then cleaved by the ribonuclease Dicer into siRNAs of 21 to 24 nucleotides in length. These siRNAs ultimately guide the RNA-induced silencing complex (RISC) to degrade the target transcript2.
Different vectors have been employed in VIGS and one of the most frequently used is based on tobacco rattle virus (TRV). TRV is a bipartite virus and, as such, two different A. tumefaciens strains are used for VIGS. One carries pTRV1, which encodes the replication and movement viral functions while the other, pTRV2, harbors the coat protein and the sequence used for VIGS6,7. Inoculation of Nicotiana benthamiana and tomato seedlings with a mixture of both strains results in gene silencing. Silencing of the endogenous phytoene desaturase (PDS) gene, which causes photobleaching, is used as a control for VIGS efficiency. It should be noted, however, that silencing in tomato is usually less efficient than in N. benthamiana. RNA transcript abundance of the gene of interest should always be measured to ensure that the target gene has efficiently been down-regulated. Nevertheless, heterologous gene sequences from N. benthamiana can be used to silence their respective orthologs in tomato and vice versa8.

Virus-induced Gene Silencing VIGS in Nicotiana benthamiana and Tomato

Description of a virus-induced gene silencing (VIGS) method for knock-down of gene expression in Nicotiana benthamiana and tomato.

Virus-induzierten Gene Silencing (VIGS) in Nicotiana benthamiana Und Tomaten

RNA interference (RNAi) is a highly specific gene-silencing phenomenon triggered by dsRNA1. This silencing mechanism uses two major classes of RNA ...

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

Mit dem Gene Pulser MXcell Elektroporation System zur Primary Cells mit hohem Wirkungsgrad zu transfizieren

Using an Automated Cell Counter to Simplify Gene Expression Studies: siRNA Knockdown of IL-4 Dependent Gene Expression in Namalwa Cells

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only to study the effects of downregulating single genes, but also to interrogate signaling pathways and other complex interaction networks.  These pathway analyses require both the use of relevant cellular models and methods that cause less perturbation to the cellular physiology.  Electroporation is increasingly being used as an effective way to introduce siRNA and other nucleic acids into difficult to transfect cell lines and primary cells without altering the signaling pathway under investigation. There are multiple critical steps to a successful siRNA experiment, and there are ways to simplify the work while improving the data quality at several experimental stages.  To help you get started with your siRNA mediated gene knockdown project, we will demonstrate how to perform a pathway study complete from collecting and counting the cells prior to electroporation through post transfection real-time PCR gene expression analysis.  The following study investigates the role of the transcriptional activator STAT6 in IL-4 dependent gene expression of CCL17 in a Burkitt lymphoma cell line (Namalwa).  The techniques demonstrated are useful for a wide range of siRNA-based experiments on both adherent and suspension cells.  We will also show how to streamline cell counting with the TC10 automated cell counter, how to electroporate multiple samples simultaneously using the MXcell electroporation system, and how to simultaneously assess RNA quality and quantity with the Experion automated electrophoresis system.

This procedure describes a quick and easy workflow to introduce siRNA into difficult to transfect cell lines and follow gene expression by real-time PCR. Use of an automated cell counter, multi-well electroporation plate, and automated electrophoresis station provide quick and reliable results without the need for expensive robotic handling.

Verwendung eines automatisierten Cell Counter zu Genexpressionsstudien Simplify: siRNA Knockdown von IL-4 abhängige Genexpression in Namalwalzellen

The use of siRNA mediated gene knockdown is continuing to be an important tool in studies of gene expression.  siRNA studies are being conducted not only ...

In vitro Reconstitution of the Active T. castaneum Telomerase

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more than a decade. Here, we present methods for the isolation of the recombinant Tribolium castaneum TERT (TcTERT) and the reconstitution of the active T. castaneum telomerase ribonucleoprotein (RNP) complex in vitro.
Telomerase is a specialized reverse transcriptase1 that adds short DNA repeats, called telomeres, to the 3' end of linear chromosomes2 that serve to protect them from end-to-end fusion and degradation. Following DNA replication, a short segment is lost at the end of the chromosome3 and without telomerase, cells continue dividing until eventually reaching their Hayflick Limit4. Additionally, telomerase is dormant in most somatic cells5 in adults, but is active in cancer cells6 where it promotes cell immortality7.
The minimal telomerase enzyme consists of two core components: the protein subunit (TERT), which comprises the catalytic subunit of the enzyme and an integral RNA component (TER), which contains the template TERT uses to synthesize telomeres8,9. Prior to 2008, only structures for individual telomerase domains had been solved10,11. A major breakthrough in this field came from the determination of the crystal structure of the active12, catalytic subunit of T. castaneum telomerase, TcTERT1.
Here, we present methods for producing large quantities of the active, soluble TcTERT for structural and biochemical studies, and the reconstitution of the telomerase RNP complex in vitro for telomerase activity assays. An overview of the experimental methods used is shown in Figure 1.

In vitro Reconstitution of the Active T. castaneum Telomerase

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more than a decade. Here, we present methods for the isolation of the recombinant Tribolium castaneum TERT (TcTERT) and the reconstitution of the active T. castaneum telomerase ribonucleoprotein (RNP) complex in vitro.

In vitro Rekonstitution der Active T. castaneum Telomerase

Efforts to isolate the catalytic subunit of telomerase, TERT, in sufficient quantities for structural studies, have been met with limited success for more ...

Agrobacterium-Mediated Virus-Induced Gene Silencing Assay In Cotton

Cotton (Gossypium hirsutum) is one of the most important crops worldwide. Considerable efforts have been made on molecular breeding of new varieties. The large-scale gene functional analysis in cotton has been lagged behind most of the modern plant species, likely due to its large size of genome, gene duplication and polyploidy, long growth cycle and recalcitrance to genetic transformation1. To facilitate high throughput functional genetic/genomic study in cotton, we attempt to develop rapid and efficient transient assays to assess cotton gene functions.
Virus-Induced Gene Silencing (VIGS) is a powerful technique that was developed based on the host Post-Transcriptional Gene Silencing (PTGS) to repress viral proliferation2,3. Agrobacterium-mediated VIGS has been successfully applied in a wide range of dicots species such as Solanaceae, Arabidopsis and legume species, and monocots species including barley, wheat and maize, for various functional genomic studies3,4. As this rapid and efficient approach avoids plant transformation and overcomes functional redundancy, it is particularly attractive and suitable for functional genomic study in crop species like cotton not amenable for transformation.
In this study, we report the detailed protocol of Agrobacterium-mediated VIGS system in cotton. Among the several viral VIGS vectors, the tobacco rattle virus (TRV) invades a wide range of hosts and is able to spread vigorously throughout the entire plant yet produce mild symptoms on the hosts5. To monitor the silencing efficiency, GrCLA1, a homolog gene of Arabidopsis Cloroplastos alterados 1 gene (AtCLA1) in cotton, has been cloned and inserted into the VIGS binary vector pYL156. CLA1 gene is involved in chloroplast development6, and previous studies have shown that loss-of-function of AtCLA1 resulted in an albino phenotype on true leaves7, providing an excellent visual marker for silencing efficiency. At approximately two weeks post Agrobacterium infiltration, the albino phenotype started to appear on the true leaves, with 100% silencing efficiency in all replicated experiments. The silencing of endogenous gene expression was also confirmed by RT-PCR analysis. Significantly, silencing could potently occur in all the cultivars we tested, including various commercially grown varieties in Texas. This rapid and efficient Agrobacterium-mediated VIGS assay provides a very powerful tool for rapid large-scale analysis of gene functions at genome-wide level in cotton.

We present the detailed protocol for Agrobacterium-mediated virus-induced gene silencing (VIGS) assay in cotton. The tobacco rattle virus (TRV)-derived VIGS vectors were deployed to induce RNA silencing of cotton GrCLA1, Cloroplastos alterados 1 gene. The albino phenotype caused by silencing GrCLA1 was observed at the seedling stage within 2 weeks after inoculation.

Agrobacterium-vermittelte Virus-induced gene silencing Assay In Cotton

Cotton (Gossypium hirsutum) is one of the most important crops worldwide. Considerable efforts have been made on molecular breeding of new varieties.  The ...

The MultiBac Protein Complex Production Platform at the EMBL

Proteomics research revealed the impressive complexity of eukaryotic proteomes in unprecedented detail. It is now a commonly accepted notion that proteins in cells mostly exist not as isolated entities but exert their biological activity in association with many other proteins, in humans ten or more, forming assembly lines in the cell for most if not all vital functions.1,2 Knowledge of the function and architecture of these multiprotein assemblies requires their provision in superior quality and sufficient quantity for detailed analysis. The paucity of many protein complexes in cells, in particular in eukaryotes, prohibits their extraction from native sources, and necessitates recombinant production. The baculovirus expression vector system (BEVS) has proven to be particularly useful for producing eukaryotic proteins, the activity of which often relies on post-translational processing that other commonly used expression systems often cannot support.3 BEVS use a recombinant baculovirus into which the gene of interest was inserted to infect insect cell cultures which in turn produce the protein of choice. MultiBac is a BEVS that has been particularly tailored for the production of eukaryotic protein complexes that contain many subunits.4 A vital prerequisite for efficient production of proteins and their complexes are robust protocols for all steps involved in an expression experiment that ideally can be implemented as standard operating procedures (SOPs) and followed also by non-specialist users with comparative ease. The MultiBac platform at the European Molecular Biology Laboratory (EMBL) uses SOPs for all steps involved in a multiprotein complex expression experiment, starting from insertion of the genes into an engineered baculoviral genome optimized for heterologous protein production properties to small-scale analysis of the protein specimens produced.5-8 The platform is installed in an open-access mode at EMBL Grenoble and has supported many scientists from academia and industry to accelerate protein complex research projects.

Protein complexes catalyze key cellular functions. Detailed functional and structural characterization of many essential complexes requires recombinant production. MultiBac is a baculovirus/insect cell system particularly tailored for expressing eukaryotic proteins and their complexes. MultiBac was implemented as an open-access platform, and standard operating procedures developed to maximize its utility.

Die MultiBac Protein Complex Produktion Platform am EMBL

Proteomics  research revealed the impressive complexity of eukaryotic proteomes in  unprecedented detail. It is now a commonly accepted notion that ...