I. Thaw the Cells
Take the frozen vial of TN5 cells, and thaw it in a 37&deg;C water bath. Add 5ml of insect Express medium (Invitrogen, catalog number-10486) in 25cm2 T.C flask. Note that Express five comes without Glutamine; need to add 10ml of 100X glutamine pen strep or Glutamine alone to 1 lt media. Add TN5 cells into it and incubate for 30 minutes in a 27&deg;C incubator. Then, aspirate the medium with DMSO gently without disturbing the cells attached to the bottom of flask. Add 5ml of Fresh medium.
II. Growing and Expanding the Cells
Monitor the cells every day. When flask is nearly 70% confluent, bring the cells in suspension by banging the flask on both sides and transfer the cells to 175cm2 flask by adding 21 ml of Insect express medium and 5ml of cell culture. Each T175 flask should have around 25-30ml medium as a&nbsp;final volume. Split confluent flask (approx 1 million/ml conc.) 1/4 or 1/5 as needed. Do not let cells overgrow. Count the number of passages that you have split the cells. Do not grow over passage number 30 because it may cause aging of cells resulting cell lysis. When you reach the desired volume at the concentration of 1 million/ml, infect the cells.
I generally grow up to 2 to 2.5 liters, which usually amounts to seventy 175cm2 flasks and approx. 25 to 30ml / flask, or five 1 liter Erlenmeyer flasks and approx. 400ml to 500 ml in each flask
Note: You either can grow cells in T-175 plug seal flask or Corning Erlenmeyer flask. Growing cells in Erlenmeyer Flasks is faster and easier.
III. Titering the Virus by End Point Dilution Method
<ol>
<li>Plate 3000-5000 cells per well in flat bottom 96 well plate in 200ul of Express five SFM medium. Let the cells settle at 27&deg;C for at least 30 minutes.</li>
<li>Make serial dilution of baculovirus stock. One should do 1/10 dilution in one line of 96 well U bottom plate, using 250ul per well. Dilutions are made in Express Five SFM medium. </li>
<li>Using a multichannel pipette, transfer a fixed amount (usually 20 ul) of different dilutions to the cells.</li>
<li>Culture at 27&deg;C for 7 days. To avoid the evaporation from the edge rows, wrap the edges of plate with parafilm.</li>
<li>After 7 days, check the plate and determine which dilution of virus gives a 50% infection - half the wells at this virus concentration are infected). Then use a formula to compute the titer, which is expressed in pfu/ml (pfu-plaque forming units). The formula is found in most baculovirus manuals.</li>
</ol>
IV. Infecting the cells
It is very important to know the Exact titer of virus. Add required amount of virus. For viral stock preparation the cells should be infected at Multiplicity of Infection (MOI) of not more than 1 (1pfu to 1High Five cell) Higher MOI leads to production of viral mutations. For protein production, usual amount is MO1 5-10.
Example:
The titer of mCD1d baculovirus = 1X108 pfu/ml
Add MOI=1 (to amplify the virus)= 20X10^6 cells/ flask / 1X10^8 pfu / ml=200 ul / flask
MOI= 5 to 10 (for protein production)= 1ml to 2ml For 20x10^6 cells/flask
On Day 4 after infection, look at the infected cells. They should be detached, floating, swollen and forming sausages.
V. Recovering Supernatants
Take the medium from infected flasks, and transfer to 250ml blue cap Falcon Spinning bottles. They can be autoclaved and reused. Fill the bottles evenly and centrifuge the cells in Sorvall GSA rotor at 200rpm, 20 minutes, 4&deg;C. Collect the supernatant and proceed for further purification.
VI. Purification Of Recombinant mCD1d
<ol>
<li>Dialysis and Concentration in 150mM Sodium Phosphate buffer (pH 7.4) </li>
<li>By Ni- NTA Agarose Chromatography, elute the protein mCD1d+b2m with 150mM Sodium phosphate +200mM Immidazole</li>
<li>Run Desalting column using 20mM Tris Hcl pH8 buffer to get rid of Immidazole</li>
<li>Run Anion Exchange Chromatography using MonoQ column to eliminate the remaining contaminants.</li>
<li>Concentrate to 1mg/ml using YM 30 concentrator (Millipore) </li>
<li>BirA enzymatic biotynlation of mCD1d according to manufacturer's protocol (Avidity) </li>
<li>The free biotin is eliminated by S200 column (size exclusion Chromatograpy) using phosphate buffered saline (PBS), pH7.4. An average of 2 to 3 mgs of biotynlated protein could be obtained from 2 liter of supernatant </li>
<li>Production of a-Galcer CD1d tetramer. </li>
</ol>
In order to load CD1d molecule with a-Galcer, soluble biotynlated CD1d-b2m is incubated overnight at room temperature with three fold molar excess of a-Galcer, dissolved in 0.5% Tween -20 in PBS, O.9% Sodium Chloride. Tetramers are generated by mixing of a-Galcer loaded CD1d monomers with 4 fold molar excess of PE - Conjugated streptavidin and incubating for 4 hours at room temperature. Store at 48&deg;C.

<ol>
	<li>Benlagha, K., Weiss, A., Beavis, A., Teyton, L., Bendelac, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+identification+of+glycolipipd+antigen-specific+T+cells+using+fluorecent+CD1d+tetramers.">In vivo identification of glycolipipd antigen-specific T cells using fluorecent CD1d tetramers.</a> J. Exp. Med. 191, 1895-1903 (2000).</li><li>Kinjo, Y., Wu, D., Kim, G., Xing, G. W., Poles, M. A., Ho, D. D., Tsuji, M., Kawahara, K., Wong, C. H., Kronenberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recognition+of+bacterial+glycosphingolipids+by+natural+killer+T+cells.">Recognition of bacterial glycosphingolipids by natural killer T cells.</a> Nature. 434, 520-525 (2005).</li><li>Naidenko, O. V., Maher, J. K., Ernst, W. A., Sakai, T., Modlin, R. L., Kronenberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Binding+and+antigen+presentation+of+ceramide-containing+glycolipids+by+soluble+mouse+and+human+CD1d+molecules.">Binding and antigen presentation of ceramide-containing glycolipids by soluble mouse and human CD1d molecules.</a> J. Exp. Med. 190, 1069-1080 (1999).</li><li>Porcelli, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+CD1+family:+A+third+lineage+of+antigen-+presenting+molecules.">The CD1 family: A third lineage of antigen- presenting molecules.</a> Adv. Immunol. 59, 1-98 (1995).</li><li>Sidobre, S., Kronemberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD1+tetramers:+A+powerful+tool+for+the+analysis+of+glycolipid-reactive+T+cells.">CD1 tetramers: A powerful tool for the analysis of glycolipid-reactive T cells.</a> J. Immunol. 169, 1340-1348 (2002).</li></ol>

In this procedure, it is shown how to initiate, grow, infect Insect cells and how to titer the baculovirus using these cells. The most important aspects of this procedure are maintenance of cells and to know the exact titer of baculovirus. Once you have generated CD1 tetramers, they can be used as a powerful tool for analysis of glycolipid reactive T cells. Baculovirus systems are also used widely to produce recombinant proteins, including MHC class II tetramers so this procedure has a much wider applicability.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Express Five SFM</td>
<td> Serum Free Medium</td>
<td>Invitrogen</td>
<td>10486025</td>
<td>&nbsp;</td>
<tr>
<td>High Five TM</td>
<td> Insect Cells</td>
<td>Invitrogen</td>
<td>B855-02</td>
<td>&nbsp;</td>
<tr>
<td>Glutamine Pen strep</td>
<td>Antibiotics</td>
<td>Invitrogen</td>
<td>10378-016</td>
<td>&nbsp;</td>
<tr>
<td>25cm2 TC Flask</td>
<td> Plastic</td>
<td>Fisher</td>
<td>10-126-28</td>
<td>&nbsp;</td>
<tr>
<td>175 cm2 TC Flask</td>
<td> Plug seal flask</td>
<td>Fisher</td>
<td>10-126-8</td>
<td>&nbsp;</td>
<tr>
<td>Erlenmeyer Flask</td>
<td> Cell Culture Flask</td>
<td>Fisher</td>
<td>07 200 672</td>
<td>&nbsp;</td>
<tr>
<td>YM 30 Concenterator</td>
<td>30,000 MWCO</td>
<td>Millipore</td>
<td>UFC 903096</td>
<td>&nbsp;</td>
<tr>
<td>FPLC equipment</td>
<td>&nbsp;</td>
<td>GE Healthcare</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>BrA Enzyme and Buffer</td>
<td> Biotinylation Kit</td>
<td>Avidity</td>
<td>BIRA500</td>
<td>&nbsp;</td>
<tr>
<td>Ni-NTA Agarose Column</td>
<td>His Tag Protein Purification Column</td>
<td>GE Healthcare</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Desalting column</td>
<td> To get Rod of Salt from Protein</td>
<td>GE Healthcare</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>MonoQ Column</td>
<td>Anion Exchange Chromatgraphy</td>
<td>GE Healthcare</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>S200 Column</td>
<td> Size Exclusion Chromatography</td>
<td>GE Healthcare</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>alpha-Galcer</td>
<td> Glycolipid</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>PE- Streptavidin</td>
<td> For conjugating Protein</td>
<td>Molecular Probe</td>
<td> S-866</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

a method for production of recombinant mcd1d protein in insect cells.

CD1 proteins constitute a third class of antigen-presenting molecules. They are cell surface glycoproteins, expressed as approximately 50-kDa glycosylated heavy chains that are noncovalently associated with beta2-microglobulin. They bind lipids rather than peptides. Although their structure confirms the similarity of CD1 proteins to MHC class I and class II antigen presenting molecules, the mCD1d groove is relatively narrow, deep, and highly hydrophobic and it has two binding pockets instead of the several shallow pockets described for the classical MHC-encoded antigen-presenting molecules. Based upon their amino acid sequences, such a hydrobphobic groove provides an ideal environment for the binding of lipid antigens. The Natural Killer T (NKT) cells use their TCR to recognize glycolipids bound to or presented by CD1d. T cells reactive to lipids presented by CD1 have been involved in the protection against autoimmune and infectious diseases and in tumor rejection. Thus, the ability to identify, purify , and track the response of CD1-reactive NKT cell is of great importance . The generation of tetramers of alpha Galactosyl ceramide (a-Galcer) with CD1d has significant insight into the biology of NKT cells. Tetramers constructed from other CD1 molecules have also been generated and these new reagents have greatly expanded the knowledge of the functions of lipid-reactive T cells, with potential use in monitoring the response to lipid-based vaccines and in the diagnosis of autoimmune diseases and other treatments.

Watch this Scientific Journal Video about A Method For Production of Recombinant mCD1d Protein in Insect Cells. at JoVE.com

A Method For Production of Recombinant mCD1d Protein in Insect Cells.

A Method to prepare Insect cells and infect them with baculovirus for the the purpose of production of recombinant mCD1d proteinand generating mCD1d tetramers.

CD1 proteins constitute a third class of antigen-presenting molecules. They are cell surface glycoproteins, expressed as approximately 50-kDa glycosylated ...

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10.6K Views.  La Jolla Institute for Allergy and Immunology. A Method to prepare Insect cells and infect them with baculovirus for the the purpose of production of recombinant mCD1d proteinand generating mCD1d tetramers.

Video: A Method For Production of Recombinant mCD1d Protein in Insect Cells.

A Protocol for Phage Display and Affinity Selection Using Recombinant Protein Baits

Using recombinant phage as a scaffold to present various protein portions encoded by a directionally cloned cDNA library to immobilized bait molecules is an efficient means to discover interactions. The technique has largely been used to discover protein-protein interactions but the bait molecule to be challenged need not be restricted to proteins. The protocol presented here has been optimized to allow a modest number of baits to be screened in replicates to maximize the identification of independent clones presenting the same protein. This permits greater confidence that interacting proteins identified are legitimate interactors of the bait molecule. Monitoring the phage titer after each affinity selection round provides information on how the affinity selection is progressing as well as on the efficacy of negative controls. One means of titering the phage, and how and what to prepare in advance to allow this process to progress as efficiently as possible, is presented. Attributes of amplicons retrieved following isolation of independent plaque are highlighted that can be used to ascertain how well the affinity selection has progressed. Trouble shooting techniques to minimize false positives or to bypass persistently recovered phage are explained. Means of reducing viral contamination flare up are discussed.

Phage display is a powerful technique to capture proteins or protein moieties that interact with an immobilized molecule of interest. Once a decision of the type of phage cDNA library to create and screen has been made, the protocol described here permits efficient affinity selection leading to identification of interactors.

Using  recombinant phage as a scaffold to present various protein portions encoded by  a directionally cloned cDNA library to immobilized bait molecules ...

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.

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

Investigating Protein-protein Interactions in Live Cells Using Bioluminescence Resonance Energy Transfer

Assays based on Bioluminescence Resonance Energy Transfer (BRET) provide a sensitive and reliable means to monitor protein-protein interactions in live cells. BRET is the non-radiative transfer of energy from a 'donor' luciferase enzyme to an 'acceptor' fluorescent protein. In the most common configuration of this assay, the donor is Renilla reniformis luciferase and the acceptor is Yellow Fluorescent Protein (YFP). Because the efficiency of energy transfer is strongly distance-dependent, observation of the BRET phenomenon requires that the donor and acceptor be in close proximity. To test for an interaction between two proteins of interest in cultured mammalian cells, one protein is expressed as a fusion with luciferase and the second as a fusion with YFP. An interaction between the two proteins of interest may bring the donor and acceptor sufficiently close for energy transfer to occur. Compared to other techniques for investigating protein-protein interactions, the BRET assay is sensitive, requires little hands-on time and few reagents, and is able to detect interactions which are weak, transient, or dependent on the biochemical environment found within a live cell. It is therefore an ideal approach for confirming putative interactions suggested by yeast two-hybrid or mass spectrometry proteomics studies, and in addition it is well-suited for mapping interacting regions, assessing the effect of post-translational modifications on protein-protein interactions, and evaluating the impact of mutations identified in patient DNA.

Interactions between proteins are fundamental to all cellular processes. Using Bioluminescence Resonance Energy Transfer, the interaction between a pair of proteins can be monitored in live cells and in real time. Furthermore, the effects of potentially pathogenic mutations can be assessed.

Assays based on Bioluminescence Resonance Energy Transfer (BRET) provide a sensitive and reliable means to monitor protein-protein interactions in live ...

Recombinant Protein Expression for Structural Biology in HEK 293F Suspension Cells: A Novel and Accessible Approach

The expression and purification of large amounts of recombinant protein complexes is an essential requirement for structural biology studies. For over two decades, prokaryotic expression systems such as E. coli have dominated the scientific literature over costly and less efficient eukaryotic cell lines. Despite the clear advantage in terms of yields and costs of expressing recombinant proteins in bacteria, the absence of specific co-factors, chaperones and post-translational modifications may cause loss of function, mis-folding and can disrupt protein-protein interactions of certain eukaryotic multi-subunit complexes, surface receptors and secreted proteins. The use of mammalian cell expression systems can address these drawbacks since they provide a eukaryotic expression environment. However, low protein yields and high costs of such methods have until recently limited their use for structural biology. Here we describe a simple and accessible method for expressing and purifying milligram quantities of protein by performing transient transfections of suspension grown HEK (Human Embryonic Kidney) 293F cells.

The expression of recombinant proteins by mammalian systems is becoming an attractive method for producing protein complexes for structural biology. Here we present a simple yet highly efficient expression system using suspension grown mammalian cells to purify protein complexes for structural studies.

The expression and purification of large amounts of recombinant protein complexes is an essential requirement for structural biology studies. For over two ...

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.

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

A Comparative Analysis of Recombinant Protein Expression in Different Biofactories: Bacteria, Insect Cells and Plant Systems

Plant-based systems are considered a valuable platform for the production of recombinant proteins as a result of their well-documented potential for the flexible, low-cost production of high-quality, bioactive products.
In this study, we compared the expression of a target human recombinant protein in traditional fermenter-based cell cultures (bacterial and insect) with plant-based expression systems, both transient and stable.
For each platform, we described the set-up, optimization and length of the production process, the final product quality and the yields and we evaluated provisional production costs, specific for the selected target recombinant protein.
Overall, our results indicate that bacteria are unsuitable for the production of the target protein due to its accumulation within insoluble inclusion bodies. On the other hand, plant-based systems are versatile platforms that allow the production of the selected protein at lower-costs than Baculovirus/insect cell system. In particular, stable transgenic lines displayed the highest-yield of the final product and transient expressing plants the fastest process development. However, not all recombinant proteins may benefit from plant-based systems but the best production platform should be determined empirically with a case-by-case approach, as described here.

In this study the expression of a target human recombinant protein in different production platforms was compared. We focused on traditional fermenter-based cultures and on plants, describing the set-up of each system and highlighting, on the basis of the reported results, the inherent limits and advantages for each platform.

Plant-based systems are considered a valuable platform for the production of recombinant proteins as a result of their well-documented potential for the ...

Nephrotoxin Microinjection in Zebrafish to Model Acute Kidney Injury

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid decline in renal function and development of the clinical syndrome known as acute kidney injury (AKI). Pharmacological agents used to treat medical circumstances ranging from bacterial infection to cancer, when administered individually or in combination with other drugs, can initiate AKI. Zebrafish are a useful animal model to study the chemical effects on renal function in vivo, as they form an embryonic kidney comprised of nephron functional units that are conserved with higher vertebrates, including humans. Further, zebrafish can be utilized to perform genetic and chemical screens, which provide opportunities to elucidate the cellular and molecular facets of AKI and develop therapeutic strategies such as the identification of nephroprotective molecules. Here, we demonstrate how microinjection into the zebrafish embryo can be utilized as a paradigm for nephrotoxin studies.

Renal injuries incurred from nephrotoxins, which include drugs ranging from antibiotics to chemotherapeutics, can result in complex disorders whose pathogenesis remains incompletely understood. This protocol demonstrates how zebrafish can be used for disease modeling of these conditions, which can be applied to the identification of renoprotective measures.

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid ...

A Graphical User Interface for Software-assisted Tracking of Protein Concentration in Dynamic Cellular Protrusions

Filopodia are dynamic, finger-like cellular protrusions associated with migration and cell-cell communication. In order to better understand the complex signaling mechanisms underlying filopodial initiation, elongation and subsequent stabilization or retraction, it is crucial to determine the spatio-temporal protein activity in these dynamic structures. To analyze protein function in filopodia, we recently developed a semi-automated tracking algorithm that adapts to filopodial shape-changes, thus allowing parallel analysis of protrusion dynamics and relative protein concentration along the whole filopodial length. Here, we present a detailed step-by-step protocol for optimized cell handling, image acquisition and software analysis. We further provide instructions for the use of optional features during image analysis and data representation, as well as troubleshooting guidelines for all critical steps along the way. Finally, we also include a comparison of the described image analysis software with other programs available for filopodia quantification. Together, the presented protocol provides a framework for accurate analysis of protein dynamics in filopodial protrusions using image analysis software.

We present a software solution for semi-automated tracking of relative protein concentration along the length of dynamic cellular protrusions.

Filopodia are dynamic, finger-like cellular protrusions associated with migration and cell-cell communication. In order to better understand the complex ...

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.

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

Production and Imaging of Recombinant Protein-Filled Vesicles from &lt;em&gt;E. coli&lt;/em&gt;

Optimized Production and Analysis of Recombinant Protein-Filled Vesicles from E. coli

This innovative system, using a short peptide tag, that exports multiple recombinant proteins in membrane bound vesicles from E. coli, provides an effective solution to a range of problems associated with bacterial recombinant protein expression. These recombinant vesicles compartmentalise proteins within a micro-environment that facilitates the production of otherwise challenging, toxic, insoluble, or disulfide-bond containing proteins from bacteria. Protein yield is increased considerably when compared to typical bacterial expression in the absence of the vesicle-nucleating peptide tag. The release of vesicle-packaged proteins supports isolation from the culture medium&#160;and permits long-term active protein storage. This technology gives rise to increased yields of vesicle-packaged, functional proteins for simplified downstream processing for a diverse range of applications from applied biotechnology to discovery science and medicine. In the present article and the associated video, a detailed protocol of the method is provided, which highlights key steps in the methodology to maximize recombinant protein-filled vesicle production.

Author Spotlight: The Production of Recombinant Proteins 

The present protocol describes a detailed method for the bacterial production of recombinant proteins, including typically insoluble or disulfide-bond containing proteins, packaged inside extracellular membrane-bound vesicles. This has the potential to be applied to versatile areas of scientific research, including applied biotechnology and medicine.