Name: transient expression of foreign genes in insect cells (sf9) for protein functional assay
Uploaded: 2018-02-22T13:00:00
Description: Watch this Scientific Journal Video about Transient Expression of Foreign Genes in Insect Cells sf9 for Protein Functional Assay at JoVE.com

Wir danken Dr. Jian-Horng Leu des Institute of Marine Biology, National Taiwan Ocean University für die Bereitstellung von 3 Plasmid-Konstruktionen. Diese Forschung wurde von Grant 106-2311-B-197-001 - aus dem Ministerium für Wissenschaft und Technologie (MOST) unterstützt.

1. Vorbereitungen
<ol><li>Insekt Zellkultur<ol>
<li>50 mL Zellkulturmedium vorzubereiten. Hierzu hinzufügen 500 µL von Antibiotika (Amphotericin B = 0,25 µg/mL, Penicillin = 100 Einheit/mL Streptomycin = 100 µg/mL) und 5 mL Hitze-inaktivierten fötalen Rinderserum in serumfreien Zellkulturmedium (ohne FBS oder Antibiotika). Hinweis: Hitze der fötalen Rinderserum bei 65 ° C für 30 min in einem Wasserbad vor Gebrauch.</li>
		<li>Pflegen von Spodoptera Frugiperda (Lepidoptera: Noctuidae...

<ol>
	<li>Miller, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculoviruses+as+gene+expression+vectors.">Baculoviruses as gene expression vectors.</a> Annual Reviews in Microbiology. 42 (1), 177-199 (1988).</li><li>Theilmann, D. A., Fauquet, C. M., Mayo, M. A., Maniloff, J., Desselberger, U., Ball, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Family+Baculoviridae.">Family Baculoviridae.</a> Virus Taxonomy: Eighth Report of the International Committee on Taxonomy of Viruses. , 1129-1185 (2005).</li><li>Nai, Y. S., Huang, Y. F., Chen, T. H., Chiu, K. P., Wang, C. H., Shields, V. D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+nucleopolyhedrovirus'+taxonomic+position.">Determination of nucleopolyhedrovirus' taxonomic position.</a> Biological Control of Pest and Vector Insects. , 169-200 (2017).</li><li>Friesen, P. D., Miller, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+baculovirus+early+gene+expression.">Regulation of baculovirus early gene expression.</a> The Baculoviruses. , 141-170 (1997).</li><li>Smith, G. E., Summers, M., Fraser, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+human+beta+interferon+in+insect+cells+infected+with+a+baculovirus+expression+vector.">Production of human beta interferon in insect cells infected with a baculovirus expression vector.</a> Mol. Cell. Biol. 3 (12), 2156-2165 (1983).</li><li>Luckow, V. A., Summers, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trends+in+the+development+of+baculovirus+expression+vectors.">Trends in the development of baculovirus expression vectors.</a> Nature Biotechnol. 6 (1), 47-55 (1988).</li><li>Jarvis, D. L., Finn, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modifying+the+insect+cell+N-glycosylation+pathway+with+immediate+early+baculovirus+expression+vectors.">Modifying the insect cell N-glycosylation pathway with immediate early baculovirus expression vectors.</a> Nature Biotechnol. 14 (1996), 1288-1292 (1996).</li><li>Clem, R. J., Miller, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+programmed+cell+death+by+the+baculovirus+genes+p35+and+iap.">Control of programmed cell death by the baculovirus genes p35 and iap.</a> Mol. Cell. Biol. 14, 5212-5222 (1994).</li><li>Leu, J. H., Kuo, Y. C., Kou, G. H., Lo, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+cloning+and+characterization+of+an+inhibitor+of+apoptosis+protein+(IAP)+from+the+tiger+shrimp,+Penaeus+monodon.">Molecular cloning and characterization of an inhibitor of apoptosis protein (IAP) from the tiger shrimp, Penaeus monodon.</a> Dev. Comp. Immunol. 32, 121-133 (2008).</li><li>Zhao, Y. G., Eggleston, P. E. <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+promoters+for+transient+gene+expression+in+cultured+mosquito+cells.">Comparative analysis of promoters for transient gene expression in cultured mosquito cells.</a> Insect Mol. Biol. 8 (1), 31-38 (1999).</li><li>Nai, Y. S., Yang, Y. T., Kim, J. S., Wu, C. Y., Chen, Y. W., Wang, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculoviral+IAP2+and+IAP3+encoded+by+Lymantria+xylina+multiple+nucleopolyhedrovirus+(LyxyMNPV)+suppress+insect+cell+apoptosis+in+a+transient+expression+assay.">Baculoviral IAP2 and IAP3 encoded by Lymantria xylina multiple nucleopolyhedrovirus (LyxyMNPV) suppress insect cell apoptosis in a transient expression assay.</a> Appl. Entomol. Zool. 51, 305-316 (2016).</li><li>Eslami, A., Lujan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Western+Blotting:+Sample+Preparation+to+Detection.">Western Blotting: Sample Preparation to Detection.</a> J. Vis. Exp. (44), e2359 (2010).</li><li>. Basic Methods in Cellular and Molecular Biology. Separating Protein with SDS-PAGE Available from: <a target="_blank" href="https://www.jove.com/science-education/5058/separating-protein-with-sds-page">https://www.jove.com/science-education/5058/separating-protein-with-sds-page</a> (2017)</li><li>Vucic, D., Kaiser, W. J., Harvey, A. J., Miller, L. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+reaper-induced+apoptosis+by+interaction+with+inhibitor+of+apoptosis+proteins+(IAPs).">Inhibition of reaper-induced apoptosis by interaction with inhibitor of apoptosis proteins (IAPs).</a> Proc. Natl. Acad. Sci. USA. 94, 10183-10188 (1997).</li></ol>

Das Konzept der Hitze Schock-basierte pDHsp/V5-His/sf9 Zellsystem wurde erstmals von Clem Et Al. 19948beschrieben. Vergleich der Baculoviral gen Promotor (IE1) und Drosophila hsp70 zeigte, dass hsp70 hatte eine höhere Effizienz in Mücke Zellen10. Darüber hinaus konnte das Timing der Proteinexpression aufgrund der Hitze-Schock-Induktion, genau nach Hitze-Schock-Behandlung kontrolliert werden. Dieses System galt dann für Protein funktio...

Zwei Eiweiß Expressionssysteme werden häufig für die Herstellung von Proteinen: intramolekulare Protein Expressionssysteme (Escherichia coli Gene Expressionssystem) und Eukaryote Expressionssysteme für Protein. Ein beliebtes Eukaryote Protein Ausdruck System ist das Baculovirus Ausdruck Vektor System (BEV)1. Baculoviren dienten zuerst als weltweite biologische Bekämpfungsmittel von Land- und forstwirtschaftliche Schädlinge. In den letzten Jahrzehnten wurden Baculoviren als biotechnologische Werkzeuge für Protein Expressionsvektoren sowie entwickelt. Die Genome von Baculoviren bestehen aus kreisförmigen doppelsträngige DNA und umhüllten Nucleocapsids2. Heute, mehr als 78 Baculovirus wurden Isolate sequenzierten3. Basierend auf den zeitlichen Kaskade von Baculoviral gen Ausdrücke in Wirtszellen Insekt, konnten die Gentranskription in vier zeitliche Kaskaden, einschließlich der sofortigen-früh, verzögert-frühe, späte und sehr späte Gene4eingestuft werden.
BEVSs wurden ausgewiesen, so dass die sehr späten gen Promotoren (d.h., Polyeder oder p10 Promotor) verwendet wurden, um die Zielgene fahren während der rekombinanten Baculovirus durch homologe Rekombination erzeugt wurde. Ausdruck von Fremdproteinen in Insektenzellen durch rekombinante Baculovirus ist ähnlich dem von Säugetieren Proteine in post-translationalen Modifikationen (geeignet für Glykoprotein Produktion). So wurde das Baculovirus verbreitete5,6,7. Eine Einschränkung ist jedoch das Vorhandensein von verschiedenen N-Glykosylierung Wege in Insektenzellen7.
Daher wurde eine neue Baculovirus Expressionssystems Expressionssystems transiente gen entwickelt. Dieses System drückt Fremdgene unter dem Laufwerk Baculoviral unmittelbaren frühen Förderer (dh-1 -Promotor) in Insektenzellen. Durch den Einsatz dieses Systems kann das Zielprotein sofort unter die Kontrolle des dh-1 Promotors ausgedrückt werden, während des Änderns des N-Glykosylierung Weges in Insektenzellen, wodurch bessere N-linked Oligosaccharide7. Darüber hinaus Baculoviral unmittelbaren frühen Gene sind von der Wirtszelle RNA-Polymerase II transkribiert und erfordern keine virale Faktoren für Aktivierung4. Daher können Fremdeiweiße in Insektenzellen innerhalb kurzer Zeit ausgedrückt werden. Bis heute ist die transiente ist gen Expressionssystems eine der wichtigsten Technologien zur Ausführung von Protein funktionelle Assays in Baculovirus in Vitro Zellkultursystem. Das System kann angewendet werden, um die Funktion des Baculovirus oder Fremdeiweiße zu analysieren. Eines der im Handel erhältlichen transiente gen Ausdruck Systeme basiert auf die unmittelbaren frühen gen (IE) Förderer von Orgyia Pseudotsugata multicapsid Nucleopolyhedrovirus (OpMNPV) (OpIE2 und OpIE1 Promotoren).
Im Untergeschoss der Expression von Fremdgenen in Insektenzellen war jedoch noch ein Problem, als Promotor-basierte transiente gen Expressionssystems OpIE verwendeten8,9,10war. So wurde ein anderes Transienten gen Ausdruck System basierend auf der Projektträger der Drosophila Hitze Shock Protein 70 (hsp70) gen8,9erstellt. Die Förderer der hsp70 arbeitet effizienter als Baculoviral IE Promotor, wenn durch einen Hitzeschock in Insektenzellen10. In diesem System wurden die Zielgene unter dem Laufwerk von Drosophila Hitze Schock 70 (Dhsp70) Promoter geäußert. Fremdgene können leicht in die transiente gen Ausdruck Plasmid von PCR-basierten Klonen Methoden geklont werden. Darüber hinaus kann die Kontrolle des Zeitpunkts für die Genexpression durch Hitze Schock Induktion durchgeführt werden.
In diesem Bericht, wir folgen dem Ansatz und drei verschiedenen Trunkierungen des Baculoviral-Gens (Inhibitor der Apoptose 3, iap3 von Lymantria Xylina MNPV) mittels Hitze Schock-basierte transiente Protein Expressionssystems und weiter gelten Sie diese exprimierten Proteine auf Anti-apoptotische Aktivitätsanalyse. Dieses System kann entweder schnell Fremdeiweiße ausdrücken oder zur Bewertung der Anti-apoptotische Proteinaktivität in sf9 Zellen, wobei er auch das Potenzial für andere Protein Aktivität Assays gelten weiter angewendet werden.

<table>
	<tbody>
		<tr>
			<td>Antibiotic-Antimycotic, 100X</td>
			<td>Gibco</td>
			<td>15240-062</td>
			<td>for insect cell culture</td>
		</tr>
		<tr>
			<td>Certified Foetal Bovine Serum</td>
			<td>Bioind</td>
			<td>04-001-1A</td>
			<td></td>
		</tr>
		<tr>
			<td>Sf-900 II SFM</td>
			<td>Thermo Fisher</td>
			<td>10902096</td>
			<td>serum-free cell culture medium</td>
		</tr>
		<tr>
			<td>Sf9 cells</td>
			<td>ATCC</td>
			<td>CRL-1711</td>
			<td></td>
		</tr>
		<tr>
			<td>25cm2 cell culture flask</td>
			<td>Nunc, Thermo Fisher</td>
			<td>156340</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted light microscopy</td>
			<td>WHITED</td>
			<td>WHITED WI-400</td>
			<td></td>
		</tr>
		<tr>
			<td>RBC HIT Competent Cell</td>
			<td>Bioman</td>
			<td>RH618-J80</td>
			<td>Escherichia coli (DH5&#945;)</td>
		</tr>
		<tr>
			<td>L.B. Broth (Miller)</td>
			<td>Bioman</td>
			<td>LBL407</td>
			<td></td>
		</tr>
		<tr>
			<td>Agar, Bacteriological Grade</td>
			<td>Bioman</td>
			<td>AGR001</td>
			<td></td>
		</tr>
		<tr>
			<td>Zeocin</td>
			<td>Invitrogen</td>
			<td>ant-zn-1</td>
			<td>selection antibiotic</td>
		</tr>
		<tr>
			<td>PCR Master Mix (2X)</td>
			<td>ThermoFisher</td>
			<td>K0171</td>
			<td></td>
		</tr>
		<tr>
			<td>Geneaid Midi Plasmid Kit (Endotoxin Free)</td>
			<td>Geneaid</td>
			<td>PIE25</td>
			<td></td>
		</tr>
		<tr>
			<td>Actinomycin D</td>
			<td>SIGMA</td>
			<td>A9415</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning 50 mL centrifuge tubes</td>
			<td>SIGMA</td>
			<td>CLS430829-500EA</td>
			<td>50 mL tubes</td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>Gizmo Supply Co</td>
			<td>B-CNT-SLDE-V2</td>
			<td></td>
		</tr>
		<tr>
			<td>24-Well Multidish</td>
			<td>Nunc, Thermo Fisher</td>
			<td>142475</td>
			<td>24-well plate</td>
		</tr>
		<tr>
			<td>Cellfectin II Reagent</td>
			<td>Thermo Fisher</td>
			<td>10362100</td>
			<td>cell transfectin reagent</td>
		</tr>
		<tr>
			<td>PBS-Phosphate-Buffered Saline (10X) pH 7.4</td>
			<td>Thermo Fisher</td>
			<td>AM9624</td>
			<td></td>
		</tr>
		<tr>
			<td>4&#215;SDS Loading Dye</td>
			<td>Bioman</td>
			<td>P1001</td>
			<td></td>
		</tr>
		<tr>
			<td>Immobilon-P (PVDF Blotting Membranes)</td>
			<td>Merck Milipore</td>
			<td>IPVH00010</td>
			<td>PVDF membranes</td>
		</tr>
		<tr>
			<td>Mini Trans-Blot Cell system</td>
			<td>BIO-RED</td>
			<td>1703930</td>
			<td>Blotting device</td>
		</tr>
		<tr>
			<td>Ponceau S solution</td>
			<td>SIGMA</td>
			<td>6226-79-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-V5</td>
			<td>SIGMA</td>
			<td>V8137</td>
			<td>rabbit anti-V5 antibody</td>
		</tr>
		<tr>
			<td>Goat anti-rabbit IgG-horseradish peroxidase (HRP)</td>
			<td>Jackson</td>
			<td>111-035-003</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Merck</td>
			<td>817072</td>
			<td></td>
		</tr>
		<tr>
			<td>6-Well Multidish</td>
			<td>Nunc, Thermo Fisher</td>
			<td>145380</td>
			<td></td>
		</tr>
		<tr>
			<td>0.4 % trypan blue solution</td>
			<td>AMRESCO</td>
			<td>K940-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>P10 pipetman</td>
			<td>Gilson</td>
			<td>F144802</td>
			<td></td>
		</tr>
		<tr>
			<td>P1000 pipetman</td>
			<td>Gilson</td>
			<td>F123602</td>
			<td></td>
		</tr>
		<tr>
			<td>Tape</td>
			<td>Symbio</td>
			<td>PPS7</td>
			<td>24 well tape ( 19 mm&#215;36 M)</td>
		</tr>
	</tbody>
</table>

transient expression of foreign genes in insect cells (sf9) for protein functional assay

Das vorübergehende gen Ausdruck System ist eine der wichtigsten Technologien zur Ausführung von Protein Funktionsanalyse in Baculovirus in Vitro Zellkultursystem. Dieses System wurde entwickelt um ausdrückliche Fremdgene unter die Kontrolle des Baculoviral-Promotors in transiente Expression Plasmiden. Darüber hinaus kann dieses System auf eine funktionelle Assay des Baculovirus selbst oder Fremdeiweiße angewendet werden. Das am weitesten verbreitete und kommerziell verfügbar transiente gen Ausdruck System wird basierend auf der sofortigen-früh gen (IE) Veranstalter von Orgyia Pseudotsugata multicapsid Nucleopolyhedrovirus (OpMNPV) entwickelt. Jedoch wurde eine Ebene geringe Expression von Fremdgenen in Insektenzellen beobachtet. Daher wurde eine transiente gen Expressionssystems gebaut, für die Verbesserung der Proteinexpression. In diesem System waren rekombinante Plasmide konstruiert, um die Zielsequenz unter der Kontrolle von Drosophila Hitze Schock 70 (Dhsp70) Promoter enthalten. Dieses Protokoll stellt die Anwendung von dieser Hitze Schock-basierte pDHsp/V5-HSI (V5 Epitop mit 6 Histidin) /Spodoptera Frugiperda Zelle (sf9 Zellen) System; Dieses System ist nicht nur für gen-Expression, sondern auch für die Bewertung der Anti-apoptotische Aktivität der Kandidat Proteine in Insektenzellen. Darüber hinaus ist dieses System kann entweder mit einem rekombinante Plasmid transfiziert werden oder Co transfiziert zwei potenziell funktional antagonistischen rekombinante Plasmide in Insektenzellen. Das Protokoll zeigt die Leistungsfähigkeit dieses Systems und bietet einen praktischen Fall diese Technik.

Die volle Länge und andere zwei Trunkierungen (BIR und RING-Domänen) von Ly-IAP3 von LyxyMNPV wurden in sf9 Zellen überexprimiert basierend auf der Hitze Schock-basierte pDHsp/V5-HSI /Spodoptera Frugiperda Zelle (sf9 Zellsystem). Die pDHsp/V5-HSI enthaltenen Drosophila Hitze Schock Protein Förderer, die nachgeschalteten Genexpression bei einer Temperatur von 42 ° C Zustand antreibt, mithilfe von zellulären transcriptional Faktoren und die Übersetzung System (<stro...

Watch this Scientific Journal Video about Transient Expression of Foreign Genes in Insect Cells sf9 for Protein Functional Assay at JoVE.com

Transient Expression of Foreign Genes in Insect Cells sf9 for Protein Functional Assay

Dieses Protokoll beschreibt eine Hitze Schock-induzierte Protein Expressionssystems (pDHsp/V5-His/sf9 Zellsystem), die verwendet werden können, mit dem Ausdruck Fremdeiweiße oder Bewertung der Anti-apoptotische Aktivität des potenziellen Fremdeiweiße und ihre abgeschnittenen amino Säuren in Insektenzellen.

Transiente Expression von Fremdgenen in Insekt Zellen (sf9) für funktionelle Protein Assay

The transient gene expression system is one of the most important technologies for performing protein functional analysis in the baculovirus in vitro cell ...

The overall goal of this heat shock-induced protein expression system is to evaluate protein anti-apoptotic activity in two potentially functionally antagonistic proteins in insect cells. This method can help answer key questions about the functions and activities of candidate proteins in biotechnology and proteomics, such as their anti-apoptotic activities and protein interactions. The main advantage of this technique is that the timing of gene expression is controlled by heat shock induction.So this method can provide insight into protein functional status. It can also be applied to other systems, such as mammalian protein expression. The Spodoptera frugiperda, or Sf9, insect cells used in this protocol are grown in cell culture medium in 25 square centimeter cell culture flasks at 28 degrees Celsius.Shake the cell culture flask to detach the cells from the flask. Then check under a light microscope to make sure that about 80%of the cells are detached. Transfer 50%of the cell suspension to a new 25 square centimeter cell culture flask, and allow the cells to attach at room temperature for 15 minutes.After 15 minutes, replace the medium with five milliliters of fresh culture medium, and grow in an incubator at 28 degrees Celsius. Depending on the cell growth, passage the cells every two to three days. Prior to harvesting the Sf9 cells, it is important to check the cells under the light microscope to make sure that there is no contamination by bacteria or other microorganisms.To harvest the Sf9 cells, shake the culture flask to detach the cells, and then transfer the cell suspension to a 15-milliliter tube. Using a P10 pipette, transfer 10 microliters of the cell suspension to a hemacytometer, and count the cell number under the light microscope. Plate three times 10 to the fifth cells into each well of a 24-well plate, and leave at room temperature for 15 minutes.After 15 minutes, replace the medium with 0.5 milliliters of plating medium. Prepare the cell transfection regent. For each transfection, dilute eight microliters of cell transfection reagent with 100 microliters of serum-free cell culture medium, and vortex for one second to mix.In this study, three different truncations of the baculoviral gene, inhibitor of apoptosis 3, or IAP3, will be expressed under the control of the Drosophila heat shock 70 promoter, the full-length IAP3, a truncation lacking the RING domain, and a truncation lacking the BIR domain. Add two micrograms of each plasmid DNA into 100 microliters of serum-free cell culture medium, and mix by vortexing for one second. Prepare a positive control as well.Combine the diluted plasmid DNA and diluted cell transfection reagent, and mix by vortexing. Incubate at room temperature for 30 minutes. Using a P1000 pipette, add 210 microliters of each DNA transfection reagent mixture dropwise onto the cells.Incubate at 28 degrees Celsius for five hours. After five hours, replace the plating medium with 0.5 milliliters of cell culture medium, and then seal the 24-well plate with tape. Incubate at 28 degrees.On the following day, heat shock to induce protein expression by floating the plate in a 42 degree Celsius water bath for 30 minutes. After 30 minutes, return the 24-well plate to the 28 degree Celsius incubator. Protein expression is subsequently confirmed by Western blot as described in the text protocol.To examine gene-induced cell apoptosis, first prepare Sf9 cells as demonstrated earlier. Next, transfect the cells in the same manner as before, but include one microgram of a plasmid containing an apoptosis inducer gene in each transfection reaction. Incubate at 28 degrees Celsius for five hours, replace the medium, and incubate for 16 hours.Heat shock the transfected cells at 42 degrees Celsius for 30 minutes. Incubate the cells at 28 degrees Celsius for five hours before conducting the cell viability assay. For chemical-induced cell apoptosis, plate one times 10 to the six Sf9 cells into each well of a six-well plate.Leave at room temperature for 15 minutes, and then replace the medium with one milliliter of plating medium. Transfect the cells with four micrograms of each plasmid DNA. After five hours, replace the plating medium with one milliliter of cell culture medium, and incubate the cells at 28 degrees Celsius for 16 hours.Then heat shock at 42 degrees Celsius for 30 minutes. Incubate the cells at 28 degrees Celsius for five hours post-heat shock. Then treat the transfected cells with actinomycin D to induce apoptosis.Incubate at 28 degrees Celsius for 16 hours before conducting the cell viability assay. Begin this procedure by washing the treated cells. Remove the medium from each well, add one milliliter of PBS, and leave for one minute.Wash the cells three times with PBS in this manner. Resuspend the cells in each well with one milliliter of PBS containing 04%trypan blue, and stain at room temperature for three minutes. Transfer the cell suspension into a 1.5 milliliter microfuge tube.Transfer 10 microliters of the trypan blue-stained cell suspension to a hemacytometer, and count the viable intact cells under a light microscope. Finally, perform statistical analysis as described in the text protocol. The full length and two truncations of IAP3 from Lymantria xylina MNPV were overexpressed in Sf9 cells, and Western blot was performed on cell lysates to confirm protein expression.The anti-apoptotic protein Ac-P35 was included as a positive control. All proteins could be detected in transfected cells at either one hour or five hours post-heat shock, with a higher expression at five hours. This system can be adapted to evaluate anti-apoptotic activity.For gene-induced cell apoptosis, the apoptosis inducer Drosophila Reaper was co-transfected with target gene plasmid constructs into Sf9 cells, which were subsequently heat shocked to activate gene expression. Compared to the vector Drosophila Reaper, the positive control showed high anti-apoptotic activity, reaching up to 80%of the viability rate. The other constructs showed various effects on anti-apoptotic activity.For chemical-induced cell apoptosis, only one construct was transfected into Sf9 cells, and actinomycin D was added five hours post-heat shock. Compared to the positive control or the negative control, the other constructs showed various effects on anti-apoptotic activity. Once mastered, this technique can be done in two to three days if it is performed properly.While attempting this procedure, it's important to remember to obey the operation rules of cell culture in laminar flow and check the status of cells diligently. Following this procedure, other methods, such as co-immunoprecipitation, can be performed to answer additional questions, like whether there is any interaction between the two proteins co-expressed in the insect cells. After its development, this technique paved the way for researchers in the field of biotechnology to explore protein functions in animal or microorganisms.After watching this video, you should have a good understanding of how to use this system to express foreign protein or evaluate potentially functionally antagonistic proteins in insect cells. Don't forget that working with some chemicals, like actinomycin D, can be extremely hazardous, and precautions, such as wearing gloves, should always be taken while performing this procedure.

Research

JoVE Journal

Genetics

Transient Expression of Foreign Genes in Insect Cells (sf9) for Protein Functional Assay

Controllable Ion Channel Expression through Inducible Transient Transfection

Steuerbare Ionenkanal-Expression durch induzierbare Transiente Transfektion

Transfection, the delivery of foreign nucleic acids into a cell, is a powerful tool in protein research. Through this method, ion channels can be ...

Forschung

Genetik

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

In-vitro- Biolumineszenz-Assay zirkadianen Rhythmus in Mamma Epithelzellen zu charakterisieren

The circadian rhythm is a fundamental physiological process present in all organisms that regulates biological processes ranging from gene expression to ...

Determination of the Optimal Chromosomal Location(s) for a DNA Element in Escherichia coli Using a Novel Transposon-mediated Approach

Determination of the Optimal Chromosomal Locations for a DNA Element in Escherichia coli Using a Novel Transposon-mediated Approach

Bestimmung der optimalen chromosomalen Speicherorte für eine DNA-Element in Escherichia coli mit einem neuartigen Transposon-vermittelte Ansatz

The optimal chromosomal position(s) of a given DNA element was/were determined by transposon-mediated random insertion followed by fitness selection. In ...

Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions

Maintaining Biological Cultures and Measuring Gene Expression in Aphis nerii: A Non-model System for Plant-insect Interactions

Aufrechterhaltung der biologischen Kulturen und Messung der Genexpression in Aphis Nerii: Non-Modellsystem für Pflanzen-Insekten-Interaktionen

Aphids are excellent experimental models for a variety of biological questions ranging from the evolution of symbioses and the development of polyphenisms ...

Endogenous Protein Tagging in Human Induced Pluripotent Stem Cells Using CRISPR/Cas9

Endogene Protein Tagging in menschlichen induzierten pluripotenten Stammzellen mit CRISPR/Cas9

A protocol is presented for generating human induced pluripotent stem cells (hiPSCs) that express endogenous proteins fused to in-frame&#160;N- or ...

Reverse Transcription-Loop-mediated Isothermal Amplification (RT-LAMP) Assay for Zika Virus and Housekeeping Genes in Urine, Serum, and Mosquito Samples

Reverse Transcription-Loop-mediated Isothermal Amplification RT-LAMP Assay for Zika Virus and Housekeeping Genes in Urine, Serum, and Mosquito Samples

Reverse Transkription-Loop-vermittelten Isothermen Verstärkung (RT-Lampe) Assay für Zika-Virus und Housekeeping-Gene in Urin, Serum und Moskito-Proben

Infection with Zika virus (ZIKV) can be asymptomatic in adults, however, infection during pregnancy can lead to miscarriage and severe neurological birth ...

Identification of Homologous Recombination Events in Mouse Embryonic Stem Cells Using Southern Blotting and Polymerase Chain Reaction

Identifikation der homologen Rekombinationsereignisse in embryonalen Stammzellen der Maus mit Southern Blotting und Polymerase-Kettenreaktion

Relative to the issues of off-target effects and the difficulty of inserting a long DNA fragment in the application of designer nucleases for genome ...

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Festsetzung des Ei Befruchtung Tabak Tabaci mit einer zytogenetischen Technik

A few species of sap-sucking whiteflies are some of the most damaging terrestrial pests worldwide because of the crop damage they inflict and plant ...

An Assay for Quantifying Protein-RNA Binding in Bacteria

Ein Assay zur Quantifizierung der Protein-RNA-Bindung in Bakterien

In the initiation step of protein translation, the ribosome binds to the initiation region of the mRNA. Translation initiation can be blocked by binding ...

An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells

Ein In-Vitro-Protokoll zur Bewertung von MicroRNA-Spiegeln, -Funktionen und assoziierten Zielgenen in Tumorzellen

MicroRNAs (miRNAs) are small regulatory RNAs which are recognized to modulate numerous intracellular signaling pathways in several diseases including ...