Este trabajo fue apoyado por un Ontario Tratamiento del VIH operativo de red Beca de Investigación (ROG-G645) y los Institutos Canadienses de Salud Investigator Award Nueva investigación (MSH-113554) de JEL, y la Universidad de Toronto Becas a la HA, la FCA, y JDC. Los autores desean agradecer a Marnie Fusco, Abelson Dafna y la Dra. Erica Saphire Ollmann en el Instituto de Investigación Scripps (La Jolla, CA) para las células que proporcionan, los virus Ébola vector de expresión GP y asesoramiento general.

<ol>
	<li>Celik, E., Calik, P. <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+recombinant+proteins+by+yeast+cells.">Production of recombinant proteins by yeast cells.</a> Biotechnol. Adv. , (2011).</li><li>Yokoyama, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+expression+systems+for+structural+genomics+and+proteomics.">Protein expression systems for structural genomics and proteomics.</a> Curr. Opin. Chem. Biol. 7, 39-43 (2003).</li><li>Nettleship, J. E., Assenberg, R., Diprose, J. M., Rahman-Huq, N., Owens, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+the+production+of+proteins+in+insect+and+mammalian+cells+for+structural+biology.">Recent advances in the production of proteins in insect and mammalian cells for structural biology.</a> J. Struct. Biol. 172, 55-65 (2010).</li><li>Carlson, E. D., Gan, R., Hodgman, C. E., Jewett, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-free+protein+synthesis:+Applications+come+of+age.">Cell-free protein synthesis: Applications come of age.</a> Biotechnol. Adv. , (2011).</li><li>Lee, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+the+Ebola+virus+glycoprotein+bound+to+an+antibody+from+a+human+survivor.">Structure of the Ebola virus glycoprotein bound to an antibody from a human survivor.</a> Nature. 454, 177-182 (2008).</li><li>Bowden, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+basis+of+Nipah+and+Hendra+virus+attachment+to+their+cell-surface+receptor+ephrin-B2.">Structural basis of Nipah and Hendra virus attachment to their cell-surface receptor ephrin-B2.</a> Nat. Struct. Mol. Biol. 15, 567-572 (2008).</li><li>Evans, M. J., Hartman, S. L., Wolff, D. W., Rollins, S. A., Squinto, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+expression+of+an+anti-human+C5+chimeric+Fab+utilizing+a+vector+that+replicates+in+COS+and+293+cells.">Rapid expression of an anti-human C5 chimeric Fab utilizing a vector that replicates in COS and 293 cells.</a> J. Immunol. Methods. 184, 123-138 (1995).</li><li>Ye, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-level+protein+expression+in+scalable+CHO+transient+transfection.">High-level protein expression in scalable CHO transient transfection.</a> Biotechnol. Bioeng. 103, 542-551 (2009).</li><li>Wurm, F. 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+recombinant+protein+therapeutics+in+cultivated+mammalian+cells.">Production of recombinant protein therapeutics in cultivated mammalian cells.</a> Nat Biotechnol. 22, 1393-1398 (2004).</li><li>Lee, J. E., Fusco, M. H., Hessell, A. J., Burton, D. R., Saphire, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques+and+tactics+used+in+determining+the+structure+of+trimeric,+prefusion+Ebola+virus+GP.">Techniques and tactics used in determining the structure of trimeric, prefusion Ebola virus GP.</a> Acta Cryst. 65, 1162-1180 (2009).</li><li>Aricescu, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eukaryotic+expression:+developments+for+structural+proteomics.">Eukaryotic expression: developments for structural proteomics.</a> Acta. Crystallogr. D Biol. Crystallogr. 62, 1114-1124 (2006).</li><li>Aricescu, A. R., Lu, W., Jones, E. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+time-+and+cost-efficient+system+for+high-level+protein+production+in+mammalian+cells.">A time- and cost-efficient system for high-level protein production in mammalian cells.</a> Acta. Crystallogr. D Biol. Crystallogr. D62, 1243-1250 (2006).</li><li>Chang, V. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycoprotein+structural+genomics:+solving+the+glycosylation+problem.">Glycoprotein structural genomics: solving the glycosylation problem.</a> Structure. 15, 267-273 (2007).</li><li>Lee, J. E., Fusco, M. H., Saphire, E. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+efficient+platform+for+screening+expression+and+crystallization+of+glycoproteins+produced+in+human+cells.">An efficient platform for screening expression and crystallization of glycoproteins produced in human cells.</a> Nature Protocols. 4, 592-604 (2009).</li><li>Nettleship, J. E., Rahman-Huq, N., Owens, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+production+of+glycoproteins+by+transient+expression+in+Mammalian+cells.">The production of glycoproteins by transient expression in Mammalian cells.</a> Methods Mol. Biol. 498, 245-263 (2009).</li><li>Neil, S. J., Zang, T., Bieniasz, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tetherin+inhibits+retrovirus+release+and+is+antagonized+by+HIV-1+Vpu.">Tetherin inhibits retrovirus release and is antagonized by HIV-1 Vpu.</a> Nature. 451, 425-430 (2008).</li><li>Nakamura, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterodimerization+of+the+IL-2+receptor+beta-+and+gamma-chain+cytoplasmic+domains+is+required+for+signalling.">Heterodimerization of the IL-2 receptor beta- and gamma-chain cytoplasmic domains is required for signalling.</a> Nature. 369, 330-333 (1994).</li><li>Wang, X., Rickert, M., Garcia, K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+the+quaternary+complex+of+interleukin-2+with+its+alpha,+beta,+and+gammac+receptors.">Structure of the quaternary complex of interleukin-2 with its alpha, beta, and gammac receptors.</a> Science. 310, 1159-1163 (2005).</li></ol>

No hay conflictos de interés declarado.

Las fábricas de células 10-capa son un buque eficaz para la producción de cantidades de miligramos de proteína. Una ventaja importante del uso de la fábrica de células sobre otras embarcaciones tradicionales, tales como botellas de rodillos, matraces de agitación o spinner frascos, es que no requieren la compra de cualquier equipo de laboratorio adicional. Un estándar de incubadora de CO 2 (aproximadamente 6.0 pies cúbicos) fácilmente acomodar a cuatro capas de 10 fábricas de células (Fig....

<table border="1"><tbody><tr><td> Nombre de reactivo </td><td> Empresa </td><td> Número de catálogo </td><td> Comentarios </td></tr><tr><td> La fosfatasa alcalina (BCIP / NBT) solución de sustrato líquido </td><td> Sigma </td><td> B6404 </td><td></td></tr><tr><td> Antibiótico / antimicótico, 100X </td><td> Invitrogen </td><td> 15240062 </td><td></td></tr><tr><td> Anti-HA matriz de afinidad, el clon 3F10 </td><td> Roche </td><td> 1815016 </td><td></td></tr><tr><td> Anti-HA AcM murino, el clon 16B12 </td><td> Covance </td><td> MMS-101P </td><td></td></tr><tr><td> Frasco de cultivo celular, T75 cm 2 de cultivo de tejidos tratados </td><td> Corning </td><td> 430641 </td><td></td></tr><tr><td> Frasco de cultivo celular, T225 de 2 cm de cultivo de tejidos tratados </td><td> Corning </td><td> 431082 </td><td></td></tr><tr><td>Placas de cultivo celular ,6-de cultivo de tejidos tratados </td><td> Corning </td><td> 3516 </td><td></td></tr><tr><td> Fábrica de la célula, de 10 capas CellSTACK </td><td> Corning </td><td> 3312 </td><td></td></tr><tr><td> Centramate Omega 5K cassette </td><td> Palio </td><td> OS005C12 </td><td></td></tr><tr><td> Centramate Omega 30K cassette </td><td> Palio </td><td> OS030C12 </td><td></td></tr><tr><td> Cromatografía en columna de vidrio, 1.0x10 cm </td><td> Kontes </td><td> 4204001010 </td><td></td></tr><tr><td> Ciprofloxacino </td><td> Sigma </td><td> 17850 </td><td></td></tr><tr><td> De CO 2 </td><td></td><td></td><td></td></tr><tr><td> Dulbecco modificado de Eagle medio (DMEM) </td><td> Sigma </td><td> D5796 </td><td></td></tr><tr><td> Suero fetal bovino (FBS), inactivado por calor </td><td> Invitrogen </td><td> 12484-028 </td><td></td></tr><tr><td> FuGENE HD reactivo de transfección </td><td> Promega </td><td> 4709691001 </td><td></td></tr><tr><td> GeneJuice reactivo de transfección </td><td> EMD / Merck </td><td> 70967-6 </td><td></td></tr><tr><td> Glicina </td><td> Sigma </td><td> G8898 </td><td></td></tr><tr><td> Cabra anti-ratón IgG F (ab &#39;) 2 alcalina </td><td> Thermo Scientific </td><td> 31324 </td><td></td></tr><tr><td> anticuerpo conjugado con fosfatasa </td><td></td><td></td><td></td></tr><tr><td> La hemaglutinina (HA) péptido, 100 mg </td><td> Genscript </td><td> síntesis de la costumbre </td><td></td></tr><tr><td> (Secuencia: YPYDVPDYA, y el 95% de pureza) </td><td></td><td></td><td></td></tr><tr><td> HEK 293T </td><td> ATCC </td><td> CRL-11268 </td><td></td></tr><tr><td> Household cloro (4% w / v hipoclorito de sodio) </td><td> varias marcas de fábrica están disponibles </td><td></td><td></td></tr><tr><td> Immobilon-P membrana PVDF </td><td> Millipore </td><td> IPVH07850 </td><td></td></tr><tr><td> MiniPrep kit de purificación de plásmido, PureLink rápida </td><td> Invitrogen </td><td> K2100-11 </td><td></td></tr><tr><td> Maxiprep kit de purificación de plásmido, PureLink HiPure </td><td> Invitrogen </td><td> K2100-07 </td><td></td></tr><tr><td> NaN 3 </td><td> Sigma </td><td> S8032 </td><td></td></tr><tr><td> pDISPLAY vector de expresión </td><td> Invitrogen </td><td> V660-20 </td><td></td></tr><tr><td> La penicilina / estreptomicina (penicilina / estreptomicina), 100X </td><td> Invitrogen </td><td> 15140-122 </td><td></td></tr><tr><td> Tampón fosfato salino (PBS) estéril 1X </td><td> Sigma </td><td> D8537 </td><td></td></tr><tr><td> Polietilenimina (PEI), lineales 25 kDa </td><td> Polyscience </td><td> 23966 </td><td></td></tr><tr><td> Leche descremada en polvo en seco </td><td> Clavel </td><td></td><td></td></tr><tr><td> Stericup-GP de vacío PSE unidad de filtración, </td><td> Millipore </td><td> SCGPU05RE </td><td></td></tr><tr><td> 0,22 mm, 500 ml de capacidad </td><td></td><td></td><td></td></tr><tr><td> El azul tripán </td><td> Invitrogen </td><td> 15250061 </td><td></td></tr><tr><td> Tripsina-EDTA, 0,05% (w / v) </td><td> Invitrogen </td><td> 25300-054 </td><td></td></tr><tr><td> Tween-20 al </td><td> Sigma </td><td> P7949 </td><td></td></tr><tr><td> El ácido valproico </td><td> Sigma </td><td> P4543 </td><td></td></tr><tr><td> Centramate sistema de flujo tangencial </td><td> Palio </td><td></td><td></td></tr><tr><td> CO 2 humidificado incubadora, 6.0 pies cúbicos estándar. pie </td><td> varias marcas de fábrica están disponibles </td><td></td><td></td></tr><tr><td> Electroforesis y transferencia de la unidad </td><td> varias marcas de fábrica están disponibles </td><td></td><td></td></tr><tr><td> Incubadora, 37 ° C </td><td> varias marcas de fábrica están disponibles </td><td></td><td></td></tr></tbody></table>

a convenient and general expression platform for the production of secreted proteins from human cells

Expresión de proteínas recombinantes en bacterias, típicamente E. coli, ha sido la estrategia de mayor éxito para la expresión cantidad miligramo de proteínas. Sin embargo, huéspedes procariotas son a menudo no es tan adecuado para la expresión de proteínas humanas, virales o eucarióticos, debido a la toxicidad de la macromolécula exterior, las diferencias en la maquinaria plegamiento de proteínas, o debido a la falta de modificaciones particulares co-o post-traslacional en bacterias. Los sistemas de expresión basados ​​en levadura (P. pastoris o S. cerevisiae) 1,2, baculovirus infectado insecto (S. frugiperda o T. ni) las células 3, y libre de células in vitro en los sistemas de traducción 2,4 han sido utilizados con éxito para producir proteínas de mamíferos. Intuitivamente, la mejor coincidencia es utilizar un huésped mamífero para asegurar la producción de proteínas recombinantes que contengan las adecuadas modificaciones post-traduccionales. Un número de líneas de células de mamíferos (Kid embriónico humanoney (HEK) 293, C V-1 en células O RIGEN que transportan el S V40 Larget antígeno T (COS), de ovario de hámster chino (CHO), y otros) se han utilizado con éxito para sobreexpresar cantidades de miligramos de un número de proteínas humanas 5-9. Sin embargo, las ventajas de utilizar células de mamífero son a menudo contrarrestada por mayores costos, requisito de equipo de laboratorio especializado, menores rendimientos de proteínas, y los tiempos prolongados para desarrollar líneas celulares estables de expresión. El aumento de rendimiento y las proteínas que producen más rápido, mientras mantiene los costos bajos, son factores importantes para muchos laboratorios académicos y comerciales. A continuación, describimos un tiempo-y costo-eficiente, procedimiento en dos partes para la expresión de proteínas secretadas por las células humanas de adherentes HEK 293T. Este sistema es capaz de producir microgramos de cantidades de miligramos de proteína funcional para estudios estructurales, biofísicos y bioquímicos. La primera parte, las construcciones de múltiples del gen de interés son producird en paralelo y transfectadas transitoriamente en células HEK 293T adherentes en pequeña escala. La detección y el análisis de la proteína recombinante secretada en el medio de cultivo celular se lleva a cabo mediante análisis Western blot utilizando anticuerpos disponibles comercialmente dirigidos contra una proteína etiqueta vector codificado purificación. Posteriormente, las construcciones adecuadas para la producción de proteínas en gran escala son transfectadas transitoriamente utilizando polietilenimina (PEI) en fábricas de células 10-capa. Las proteínas secretadas en litros volúmenes de medio condicionado se concentran en cantidades manejables utilizando filtración de flujo tangencial, seguido de purificación por cromatografía de afinidad anti-HA. La utilidad de esta plataforma se demuestra por su capacidad para expresar cantidades de miligramos de citoquinas, receptores de citoquinas, receptores de la superficie celular, factores intrínsecos de restricción, y glicoproteínas virales. Este método también fue utilizado con éxito en la determinación estructural de los inhibidores de la glucoproteína 5,10 triméricas virus Ébola. <p class = &quot;jove_content&quot;&gt; En conclusión, esta plataforma ofrece la facilidad de uso, velocidad y escalabilidad, además de maximizar la calidad de la proteína y la funcionalidad. Por otra parte, ningún equipo adicional, que no sea de humidificado incubadora de CO 2, se requiere. Este procedimiento puede ser expandido rápidamente a los sistemas de mayor complejidad, tales como co-expresión de los complejos de proteínas, antígenos y anticuerpos, la producción de partículas similares a virus de vacunas, o la producción de adenovirus o lentivirus para la transducción de líneas celulares difíciles.

Watch this Scientific Journal Video about A Convenient and General Expression Platform for the Production of Secreted Proteins from Human Cells at JoVE.com

A Convenient and General Expression Platform for the Production of Secreted Proteins from Human Cells

En la era genómica post-humana, la disponibilidad de proteínas recombinantes en conformaciones nativas es crucial para la investigación estructural, funcional y terapéutico y el desarrollo. Aquí se describe una prueba a gran escala y sistema de expresión de proteínas en células embrionarias humanas de riñón 293T que se pueden utilizar para producir una variedad de proteínas recombinantes.

Una expresión adecuada y el general de la Plataforma para la producción de proteínas secretadas por las células humanas

Recombinant protein expression in bacteria, typically E. coli, has been the most successful strategy for milligram quantity expression of proteins. ...

a-convenient-general-expression-platform-for-production-secreted

Research

JoVE Journal

Biology

21.0K vistas.  University of Toronto. En la era genómica post-humana, la disponibilidad de proteínas recombinantes en conformaciones nativas es crucial para la investigación estructural, funcional y terapéutico y el desarrollo. Aquí se describe una prueba a gran escala y sistema de expresión de proteínas en células embrionarias humanas de riñón 293T que se pueden utilizar para producir una variedad de proteínas recombinantes.

Video: A Convenient and General Expression Platform for the Production of Secreted Proteins from Human Cells

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.

La preparación de cultivos primarios de células hematopoyéticas de la médula ósea murina por electroporación

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

Investigación

Biología

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.

Tinción de las proteínas en geles con Coomassie G-250, sin ácido disolvente orgánico y el acético

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

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.

Utilizando el sistema de electroporación Gene Emisores MXcell para transfectar células primarias con alta eficiencia

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.

El uso de un contador de células automatizado para simplificar estudios de expresión génica: siRNA Derribo de IL-4 la expresión génica en células dependientes Namalwa

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 ...

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.

El Protein Complex Plataforma de Producción MultiBac en el EMBL

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

Efficient Production and Purification of Recombinant Murine Kindlin-3 from Insect Cells for Biophysical Studies

Kindlins are essential coactivators, with talin, of the cell surface receptors&#160;integrins and also participate in integrin outside-in signalling, and the control of gene transcription in the cell nucleus. The kindlins are ~75 kDa multidomain proteins and bind to an NPxY motif and upstream T/S cluster of the integrin &#946;-subunit cytoplasmic tail. The hematopoietically-important kindlin isoform, kindlin-3, is critical for platelet aggregation during thrombus formation, leukocyte rolling in response to infection and inflammation and osteoclast podocyte formation in bone resorption. Kindlin-3&#39;s role in these processes has resulted in extensive cellular and physiological studies. However, there is a need for an efficient method of acquiring high quality milligram quantities of the protein for further studies. We have developed a protocol, here described, for the efficient expression and purification of recombinant murine kindlin-3 by use of a baculovirus-driven expression system in Sf9 cells yielding sufficient amounts of high purity full-length protein to allow its biophysical characterization. The same approach could be taken in the study of the other mammalian kindlin isoforms.

Kindlins are fundamental to cell adhesion through integrins but studies of them have been hampered by the difficulty encountered in expressing them recombinantly in bacterial hosts. We describe here methods for their efficient production in baculovirus-infected insect cells.

Producción eficiente y purificación de recombinante murino kindlin-3 a partir de células de insecto para estudios biofísicos

Kindlins are essential coactivators, with talin, of the cell surface receptors&#160;integrins and also participate in integrin outside-in signalling, and ...

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and the inherent instability of many membrane proteins once solubilized in detergents. A protocol is described that combines ligation independent cloning of membrane proteins as GFP fusions with expression in Escherichia coli detected by GFP fluorescence. This enables the construction and expression screening of multiple membrane protein/variants to identify candidates suitable for further investment of time and effort. The GFP reporter is used in a primary screen of expression by visualizing GFP fluorescence following SDS polyacrylamide gel electrophoresis (SDS-PAGE). Membrane proteins that show both a high expression level with minimum degradation as indicated by the absence of free GFP, are selected for a secondary screen. These constructs are scaled and a total membrane fraction prepared and solubilized in four different detergents. Following ultracentrifugation to remove detergent-insoluble material, lysates are analyzed by fluorescence detection size exclusion chromatography (FSEC). Monitoring the size exclusion profile by GFP fluorescence provides information about the mono-dispersity and integrity of the membrane proteins in different detergents. Protein: detergent combinations that elute with a symmetrical peak with little or no free GFP and minimum aggregation are candidates for subsequent purification. Using the above methodology, the heterologous expression in E. coli of SED (shape, elongation, division, and sporulation) proteins from 47 different species of bacteria was analyzed. These proteins typically have ten transmembrane domains and are essential for cell division. The results show that the production of the SEDs orthologues in E. coli was highly variable with respect to the expression levels and integrity of the GFP fusion proteins. The experiment identified a subset for further investigation.

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.

Fluorescente verde a base de proteína Expresión Proyección de proteínas de membrana en<em&gt; Escherichia coli</em

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and ...

Enrichment of Extracellular Matrix Proteins from Tissues and Digestion into Peptides for Mass Spectrometry Analysis

The extracellular matrix (ECM) is a complex meshwork of cross-linked proteins that provides biophysical and biochemical cues that are major regulators of cell proliferation, survival, migration, etc. The ECM plays important roles in development and in diverse pathologies including cardio-vascular and musculo-skeletal diseases, fibrosis, and cancer. Thus, characterizing the composition of ECMs of normal and diseased tissues could lead to the identification of novel prognostic and diagnostic biomarkers and potential novel therapeutic targets. However, the very nature of ECM proteins (large in size, cross-linked and covalently bound, heavily glycosylated) has rendered biochemical analyses of ECMs challenging. To overcome this challenge, we developed a method to enrich ECMs from fresh or frozen tissues and tumors that takes advantage of the insolubility of ECM proteins. We describe here in detail the decellularization procedure that consists of sequential incubations in buffers of different pH and salt and detergent concentrations and that results in 1) the extraction of intracellular (cytosolic, nuclear, membrane and cytoskeletal) proteins and 2) the enrichment of ECM proteins. We then describe how to deglycosylate and digest ECM-enriched protein preparations into peptides for subsequent analysis by mass spectrometry.

This protocol describes a procedure for enriching ECM proteins from tissues or tumors and deglycosylating and digesting the ECM-enriched preparations into peptides to analyze their protein composition by mass spectrometry.

Enriquecimiento de la Matriz Extracelular Las proteínas de los tejidos y la digestión en péptidos para el análisis de espectrometría de masas

The extracellular matrix (ECM) is a complex meshwork of cross-linked proteins that provides biophysical and biochemical cues that are major regulators of ...

High Yield Expression of Recombinant Human Proteins with the Transient Transfection of HEK293 Cells in Suspension

The art of producing recombinant proteins with complex post-translational modifications represents a major challenge for studies of structure and function. The rapid establishment and high recovery from transiently-transfected mammalian cell lines addresses this barrier and is an effective means of expressing proteins that are naturally channeled through the ER and Golgi-mediated secretory pathway. Here is one protocol for protein expression using the human HEK293F and HEK293S cell lines transfected with a mammalian expression vector designed for high protein yields. The applicability of this system is demonstrated using three representative glycoproteins that expressed with yields between 95-120 mg of purified protein recovered per liter of culture. These proteins are the human Fc&#947;RIIIa and the rat &#945;2-6 sialyltransferase, ST6GalI, both expressed with an N-terminal GFP fusion, as well as the unmodified human immunoglobulin G1 Fc. This robust system utilizes a serum-free medium that is adaptable for expression of isotopically enriched proteins and carbohydrates for structural studies using mass spectrometry and nuclear magnetic resonance spectroscopy. Furthermore, the composition of the N-glycan can be tuned by adding a small molecule to prevent certain glycan modifications in a manner that does not reduce yield.

Laboratory-scale production of eukaryotic proteins with appropriate post-translational modification represents a significant barrier. Here is a robust protocol with rapid establishment and turnaround for protein expression using a mammalian expression system. This system supports selective amino acid, selective labeling of proteins and small molecule modulators of glycan composition.

High Yield La expresión de proteínas recombinantes humanos con la transfección transitoria de células HEK293 en Suspensión

The art of producing recombinant proteins with complex post-translational modifications represents a major challenge for studies of structure and ...

Transient Expression and Cellular Localization of Recombinant Proteins in Cultured Insect Cells

Heterologous protein expression systems are used for the production of recombinant proteins, the interpretation of cellular trafficking/localization, and the determination of the biochemical function of proteins at the sub-organismal level. Although baculovirus expression systems are increasingly used for protein production in numerous biotechnological, pharmaceutical, and industrial applications, nonlytic systems that do not involve viral infection have clear benefits but are often overlooked and underutilized. Here, we describe a method for generating nonlytic expression vectors and transient recombinant protein expression. This protocol allows for the efficient cellular localization of recombinant proteins and can be used to rapidly discern protein trafficking within the cell. We show the expression of four&#160;recombinant proteins in a commercially available insect cell line, including two aquaporin proteins from the insect Bemisia tabaci, as well as subcellular marker proteins specific for the cell plasma membrane and for intracellular lysosomes. All recombinant proteins were produced as chimeras with fluorescent protein markers at their carboxyl termini, which allows for the direct detection of the recombinant proteins. The double transfection of cells with plasmids harboring constructs for the genes of interest and a known subcellular marker allows for live cell imaging and improved validation of cellular protein localization.

Nonlytic insect cell expression systems are underutilized for production, cellular trafficking/localization, and recombinant protein functional analysis. Here, we describe methods to generate expression vectors and subsequent transient protein expression in commercially available lepidopteran cell lines. The co-localization of Bemisia tabaci aquaporins with subcellular fluorescent marker proteins is also presented.

Expresión transitoria y localización celular de proteínas recombinantes en células cultivadas de insectos

Heterologous protein expression systems are used for the production of recombinant proteins, the interpretation of cellular trafficking/localization, and ...