Name: Engineering Cell-permeable Protein (Video) | JoVE Journal
Uploaded: 2009-12-28T15:00:00.000+00:00
Duration: 21 min 8 s
Description: Learn protein transduction for delivering active proteins into mammalian cells using the Paciz vector system. This method enables efficient cellular manipulation without permanent genetic modification risks.

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We thank Oliver Br&uuml;stle and all members of the Stem Cell Engineering Group, University of Bonn, for support and valuable discussions. We thank Sabine Schenk for preparation of the SDS-PAGE and enduring support throughout the project. Nicole Russ and Anna Magerhans provided excellent technical support. Furthermore, we would like to thank Andreas B&auml;r and Sheila Mertens for the production of the movie. This work was supported by grants from the Volkswagen Foundation (Az I/77864) and the German Ministry of Education and Research (BMBF, 01 GN 0813).

Construction of expression vector and expression:
The pSESAME-Cre expression vector was constructed by inserting a Cre-encoding fragment into pSESAME via AvrII and NheI restriction sites using standard cloning methods. pSESAME encodes a fusion protein consisting of a histidine-tag, TAT-domain, NLS sequence and Cre, abbreviated HTNCre. For expression of HTNCre the pSESAME-Cre was transformed into TUNER (DE3) pLacI and used to prepare a glycerol stock.
<ol>
 <li>An over-night culture was inoculated using a pipet tip coated with transformed bacteria from the glycerol stock. The over-night culture consisted of LB media supplemented with 0.5% glucose [v/v] and carbenicillin at a final concentration of 50 μg/mL and was allowed to grow at 37°C for 16 hours.</li>
 <li>Next day the densely grown over-night culture was used to inoculate the expression culture at a ratio of 1 to 40 and was put in an incubator at 37°C. Expression culture consisted of TB media supplemented with 0.5% glucose [v/v] and ampicillin at a final concentration of 100 μg/mL.</li>
 <li>At an OD595 of 1.5 the expression culture was induced with 0.5 mM IPTG for 1 h.</li>
 <li>Subsequently bacteria were collected by centrifugation at 5000 rpm for 10 minutes in a SLA3000 rotor.</li>
 <li>Bacteria pellets were stored at minus 20°C until purification.</li>
</ol>
Purification of cell-permeable protein:
<ol>
 <li>Frozen bacteria pellets were resuspended in 10 mL lysis buffer per liter flask culture for 15 minutes at room temperature.</li>
 <li>Suspension was then incubated with 1 mg/mL lysozyme for additional 15 minutes while mixing at room temperature.</li>
 <li>25 U/mL benzonase was added afterwards and incubated while mixing for 15 minutes at room temperature.</li>
 <li>After sonification on ice for 1.5 min with 0.5 s pulses at 45% of the power, 1 mL cold tartaric salt buffer (TSB) per mL suspension was carefully added while mixing and incubated for 5 min on ice. SDS-PAGE sample of lysate fraction (L) was taken.</li>
 <li>Cleared lysate was obtained by centrifugation at 4°C for 30 min at 30,000g. SDS-PAGE samples of soluble (S) and insoluble fractions (I) were taken.</li>
 <li>The supernatant was transferred into fresh 50 mL falcon tubes and was then gently mixed for 1 h at 4°C with 2 mL of 50% Ni-NTA slurry per liter of initial expression culture.</li>
 <li>The suspension was packed into a gravity flow EconoPac column (SDS-PAGE sample of flow-through fraction (FT) was taken) and washed twice with 5 bed-volumes of washing buffer. SDS-PAGE samples of both washing fractions (W1 &amp; W2) were collected.</li>
 <li>HTNCre-containing fractions were eluted with 3 bed-volumes of elution buffer and sample of eluate fraction (E) for SDS-PAGE analysis was taken.</li>
 <li>Imidazole was removed by dialyzing elution fraction against high salt buffer twice.</li>
 <li>The protein solution was further concentrated by dialyzing against glycerol buffer twice. In all dialysis steps the ratio of buffer to sample was at least 50. This procedure resulted in a glycerol stock solution containing HTNCre at a usual concentration between 200 and 450 μM, i.e. 1 liter of expression culture will result in ~12 mg of protein. Sample of glycerol stock (GS) for SDS-PAGE analysis was collected. HTNCre stock solution can be stored at minus 20°C.</li>
</ol>
<img border="0" src="/files/ftp_upload/1627/1627fig1tmb.jpg" alt="Protein purification electrophoresis results, gel bands, column fractions, SDS-PAGE analysis." data-altupdatedat="1788235205000" data-alt="Figure 1"> Figure 1: SDS-PAGE analysis of the samples collected during the purification process of Cre recombinase. Induction of Cre expression is indicated by dominant band in lysate fraction. Although a part of the protein is insoluble the Cre protein can be further enriched as seen in eluate and glycerol stock fractions. L: Lysate, I: Insoluble, S: Supernatant, FT: Flow-through, W: Washing, E: Eluate, GS: Gylcerol Stock. Please <a href="https://www.jove.com/files/ftp_upload/1627/1627fig1.jpg">click here</a> to see a larger version of figure 1.
Protein transduction into murine embryonic stem (ES) cells:
<ol>
 <li>ES cells carrying a conditional β-Galactosidase reporter5 construct were seeded as single cells using TrypLE™ Express for dissociation of adherent cells. After 4 to 6 hours the cells had re-attached and the medium was removed.</li>
 <li>Subsequently ES cells were incubated with HTNCre-containing medium for 16 hours.
 <ul>
 <li>An appropriate amount of HTNCre protein (corresponding to 10 μM) out of the glycerol stock was diluted into ES medium and subsequently sterile filtrated (0.22 μm).</li>
 </ul></li>
 <li>After protein transduction medium was changed back to normal growth medium.</li>
 <li>After two days cells were washed with PBS and fixed with 4% Paraformaldehyde (PFA) for 10 minutes.</li>
 <li>Two additional washing steps with PBS were executed before X-Gal staining was performed.</li>
 <li>Fixed cells were covered with a layer of X-Gal staining solution6 and incubated over night at 37°C. </li>
</ol>
Representative Results:
Next day X-Gal staining solution was aspired and the cells were covered with a layer of PBS for microscopy analysis. 80 to 100% of recombined cells could be observed within the murine ES cells judged by β-Galactosidase activity.

<ol><li>Gump, J. M., Dowdy, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((TAT+transduction%3A+the+molecular+mechanism+and+therapeutic+prospects%5BTitle%5D)+AND+%22Trends+Mol+Med%22%5BJournal%5D)">TAT transduction: the molecular mechanism and therapeutic prospects.</a> Trends Mol Med. 13 (10), 443-448 (2007).</li>
<li>Edenhofer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Protein+transduction+revisited%3A+novel+insights+into+the+mechanism+underlying+intracellular+delivery+of+proteins%5BTitle%5D)+AND+%22Curr+Pharm+Des%22%5BJournal%5D)">Protein transduction revisited: novel insights into the mechanism underlying intracellular delivery of proteins.</a> Curr Pharm Des. 14 (34), 3628-3636 (2008).</li>
<li>Branda, C. S., Dymecki, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Talking+about+a+revolution%3A+The+impact+of+site-specific+recombinases+on+genetic+analyses+in+mice%5BTitle%5D)+AND+%22Dev+Cell%22%5BJournal%5D)">Talking about a revolution: The impact of site-specific recombinases on genetic analyses in mice.</a> Dev Cell. 6 (1), 7-28 (2004).</li>
<li>Nolden, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Site-specific+recombination+in+human+embryonic+stem+cells+induced+by+cell-permeant+Cre+recombinase%5BTitle%5D)+AND+%22Nat+Methods%22%5BJournal%5D)">Site-specific recombination in human embryonic stem cells induced by cell-permeant Cre recombinase.</a> Nat Methods. 3 (6), 461-467 (2006).</li>
<li>Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Inducible+site-directed+recombination+in+mouse+embryonic+stem+cells%5BTitle%5D)+AND+%22Nucleic+Acids+Res%22%5BJournal%5D)">Inducible site-directed recombination in mouse embryonic stem cells.</a> Nucleic Acids Res. 24 (4), 543-548 (1996).</li>
<li>Peitz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Enhanced+purification+of+cell-permeant+Cre+and+germline+transmission+after+transduction+into+mouse+embryonic+stem+cells%5BTitle%5D)+AND+%22Genesis%22%5BJournal%5D)">Enhanced purification of cell-permeant Cre and germline transmission after transduction into mouse embryonic stem cells.</a> Genesis. 45 (8), 508-517 (2007).</li>
<li>Bosnali, M., Edenhofer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Generation+of+transducible+versions+of+transcription+factors+Oct4+and+Sox2%5BTitle%5D)+AND+%22Biol+Chem%22%5BJournal%5D)">Generation of transducible versions of transcription factors Oct4 and Sox2.</a> Biol Chem. 389 (7), 851-861 (2008).</li>
<li>Landry, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Runx+genes+are+direct+targets+of+Scl%2FTal1+in+the+yolk+sac+and+fetal+liver%5BTitle%5D)+AND+%22Blood%22%5BJournal%5D)">Runx genes are direct targets of Scl/Tal1 in the yolk sac and fetal liver.</a> Blood. 111 (6), 3005-3014 (2008).</li>
</ol>

During the purification process of the Cre fusion protein it is important not to omit the addition of ice&nbsp;cold TBS buffer prior to centrifugation. Otherwise Cre recombinase tends to precipitate within the glycerol buffer.
If the eluate fraction appears to become turbid due to the high concentration of fusion protein additional elution buffer should be added until the solution has cleared again.
The application of 10 &mu;M of Cre fusion protein typically results in a recombination efficiency of 80 to 100%. Fetal Calf Serum (FCS) being a major component of ES cell medium strongly inhibits protein transduction. Therefore high concentration of Cre recombinase had to be used. When working in serum-free conditions less protein (0.5 - 2 &mu;M) can be used to achieve similar recombination efficiencies.
With the pSESAME vector system at hand one can apply the technique of protein transduction to other proteins including transcription factors such as Oct4 and Sox27 and Scl/Tal18.

<table><tbody><tr><td>TUNER (DE3) pLacI</td><td>Novagen, EMD Millipore</td><td>70625</td><td></td></tr><tr><td>Glycerol</td><td>Carl Roth GmbH</td><td>3783.2</td><td></td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;</td><td>Carl Roth Gmbh</td><td>T876.1</td><td></td></tr><tr><td>Trizma Base</td><td>Sigma-Aldrich</td><td>T1503</td><td></td></tr><tr><td>HCl</td><td>Carl Roth Gmbh</td><td>4625.1</td><td></td></tr><tr><td>Imidazol</td><td>Carl Roth Gmbh</td><td>X998.4</td><td></td></tr><tr><td>NaCl</td><td>Carl Roth Gmbh</td><td>9265.2</td><td></td></tr><tr><td>Yeast Extract</td><td>Carl Roth Gmbh</td><td>2363.4</td><td></td></tr><tr><td>Trypton/Pepton</td><td>Carl Roth Gmbh</td><td>8952.4</td><td></td></tr><tr><td>K&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt; </td><td>Carl Roth Gmbh</td><td>P749.2</td><td></td></tr><tr><td>KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Carl Roth Gmbh</td><td>3904.1</td><td></td></tr><tr><td>Ampicillin</td><td>Sigma-Aldrich</td><td>A9518</td><td></td></tr><tr><td>Carbenicillin</td><td>Sigma-Aldrich</td><td>6344.2</td><td></td></tr><tr><td>HEPES</td><td>Sigma-Aldrich</td><td>H3375</td><td></td></tr><tr><td>Lysozyme</td><td>Sigma-Aldrich</td><td>62971</td><td></td></tr><tr><td>Benzonase</td><td>Novagen, EMD Millipore</td><td></td><td></td></tr><tr><td>L-Tartaric acid, disodium salt </td><td>Sigma-Aldrich</td><td></td><td></td></tr><tr><td>50% Ni-NTA slurry</td><td>Invitrogen</td><td>R901-15</td><td></td></tr><tr><td>EconoPac columns</td><td>Bio-Rad</td><td>732-1010</td><td></td></tr><tr><td>Sterile filter 0,22&amp;mu;m</td><td>Whatman, GE Healthcare</td><td></td><td></td></tr><tr><td>Paraformaldehyde (PFA)</td><td>Sigma-Aldrich</td><td></td><td></td></tr><tr><td>LB medium</td><td></td><td></td><td>Yeast extract, Trypton/Pepton, NaCl</td></tr><tr><td>TB medium</td><td></td><td></td><td>Yeast extract, Trypton/Pepton, Glycerol, K&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;, KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td></tr><tr><td>Lysis Buffer</td><td></td><td></td><td>50 mM Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;, 5 mM Tris, pH 7.8</td></tr><tr><td>Tartaric Salt Buffer (TSB)</td><td></td><td></td><td>PTB containing 2 M L-Tartaric acid, disodium salt, and 20 mM Imidazol</td></tr><tr><td>Washing Buffer</td><td></td><td></td><td>PTB, 500 mM NaCl, 15 mM Imidazol</td></tr><tr><td>Elution Buffer</td><td></td><td></td><td>PTB, 500 mM NaCl, 250 mM Imidazol</td></tr><tr><td>High Salt Buffer</td><td></td><td></td><td>600 mM NaCl, 20 mM HEPES, pH 7.4</td></tr><tr><td>Gylcerol Buffer</td><td></td><td></td><td>50% glycerol, 500 mM NaCl, 20 mM HEPES, pH 7.4</td></tr><tr><td>TrypLE&amp;#8482; Express</td><td>Invitrogen</td><td></td><td></td></tr><tr><td>ESGRO (LIF)</td><td>EMD Millipore</td><td></td><td></td></tr><tr><td>NEAA</td><td>GIBCO, by Life Technologies</td><td>11140035</td><td></td></tr><tr><td>L-Glutamin</td><td>GIBCO, by Life Technologies</td><td>25030024</td><td></td></tr><tr><td>&amp;#946;-Mercapt&amp;#8211;thanol</td><td>GIBCO, by Life Technologies</td><td>31350010</td><td></td></tr><tr><td>DMEM</td><td>GIBCO, by Life Technologies</td><td>11960044</td><td></td></tr><tr><td>PBS</td><td>GIBCO, by Life Technologies</td><td></td><td></td></tr><tr><td>Fetal Calf Serum (FCS)</td><td>PAA Laboratories</td><td></td><td></td></tr><tr><td>X-Gal staining solution:</td><td></td><td></td><td>4 mM K&lt;sub&gt;3&lt;/sub&gt;(FeIII(CN)&lt;sub&gt;6&lt;/sub&gt;), 4 mM K&lt;sub&gt;4&lt;/sub&gt;(FeII(CN)&lt;sub&gt;6&lt;/sub&gt;),&lt;br/&gt;2mM MgCl&lt;sub&gt;2&lt;/sub&gt; 0.4 mg/mL X-Gal solved in PBS</td></tr><tr><td>K&lt;sub&gt;3&lt;/sub&gt;(FeIII(CN)&lt;sub&gt;6&lt;/sub&gt;)</td><td>Sigma-Aldrich</td><td>P-3367</td><td></td></tr><tr><td>K&lt;sub&gt;4&lt;/sub&gt; (FeII(CN)&lt;sub&gt;6&lt;/sub&gt;)</td><td>Sigma-Aldrich</td><td>P-9387</td><td></td></tr><tr><td>MgCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Sigma-Aldrich</td><td>M8266</td><td></td></tr><tr><td>X-Gal</td><td>Sigma-Aldrich</td><td>B4252</td><td></td></tr></tbody></table>

engineering cell-permeable protein

Engineering Cell-permeable Protein

The protein transduction technique enables the direct delivery of biologically active material into mammalian cells [for review see 1,2]. For this one can make use of the translocating ability of so-called cell penetrating peptides (CPPs), also designated as protein transduction domains (PTDs). The TAT-CPP derived from the human immunodeficiency virus type 1 (HIV-1) Tat (trans-activator of transcription) protein has been widely used. The positively charged TAT promotes cell permeability thereby overcoming the barriers of the cellular membrane by endocytosis or/and direct membrane penetration2. In combination with a nuclear localization signal (NLS) fusion proteins are able to enter the nucleus exhibiting functionality. Our video presentation demonstrates, as an exemplification for the engineering of cell-permeable proteins, the construction, production and application of a cell-permeable version of the DNA-modifying enzyme Cre.
Cre is a site-specific recombinase that is able to recognize and recombine 34 base pair loxP sites in mammalian cells in vitro and in vivo. Therefore the Cre/loxP system is widely used to conditionally induce mutations in the genome of living cells3,4. The delivery of active Cre recombinase to cells, however, represents a limitation.
We describe the pSESAME vector system, which allows a direct insertion of the gene-of-interest and provides a platform to rapidly clone different domains and tags used within the vector in a convenient and standardized manner. Rearranging of the different tags has been shown to modify the biochemical properties of the fusion proteins providing a possibility to achieve higher yield and better solubility. We demonstrate how to express and purify recombinant cell-permeant proteins in and from E. coli. The functionality of the recombinant Cre protein is finally validated in cell culture by assessing its intracellular recombinase activity.

Protein transduction enables the direct delivery of biologically active proteins into cells. In contrast to conventional methods such as DNA transfection or viral transduction this non-invasive paradigm allows highly efficient cellular manipulation in a titratable manner circumventing cellular toxicity and the risk of oncogenic transformation by permanent genetic modification.

The protein transduction technique enables the direct delivery of biologically active material into mammalian cells [for review see 1,2]. For this one can ...

The manipulation of cellular function can be achieved through the classical approaches of DNA transfection or viral transduction within the last 15 years. Another method evolved. The protein transduction biological active protein can be directly delivered into mammalian cells using small peptides fused to the protein of interest, which promotes cellular uptake.As no DNA is used, the risk of exertion agenesis is prevented. In contrast to the above mentioned classical methods. The protein transduction enables delivery of proteins in a titratable manner.Moreover, small cell populations as well as non dividing cells, such as post mitotic neurons, can be modulated. To express recombinant protein in an efficient manner, we recommend the use of the Paciz vector system. It is a modular vector system consisting of an end terminal and a C terminal variant.Both vectors allow the easy insertion of your gene of interest for the means of purification. A histidine tag is integrated as well as a protein transduction domain. In our case, touch from the HI virus promoting cellular uptake for cellular distribution.A nuclear localization signal completes the vector for control reasons fusion tags can simply be removed. Besides the arrangement of those tags can have major influence on the properties of the fusion proteins. The influence on yield and purity as well as sellability and biological function is not predictable.Hi, my name is Bernard Mus and I'm working in the stem Cell Engineering group in the Institute of Reconstructive Neurobiology in Bond, Germany. Hi, my name is Christoph P and I'm also a member of the in Hoover Lab. Our work group intensively exploits the protein transduction technique to directly deliver biological active protein into various mammalian cells, and today we want to guide you through the process of expression and purification in and from e coli.Thereafter, we would like to show you how to apply cell permanent fusion protein in cell culture to exemplify the whole procedure expression, purification and application. We make use of the site specific recombination Cree to genetically modify mouse onic stem cells.Okay.Okay. Let's get started.To inoculate the overnight culture, we make use of already transformed bacteria stored in a glycerol stock at minus 80 degrees centigrade. These bacteria already contain the vector encoding for decre recombination. Using a piper tip, we scratch a small amount of the bacteria onto the piper tip and drop it into the beaker containing the overnight culture.The overnight culture consists of LB media supplemented with glucose at a final concentration of oh 0.5%and 50 micrograms of carbonic insulin per ml. The beaker is then put into an incubator running at 37 degree centigrade for the expression of the site-specific Recombinate Cree. We are using pre-war TB media for our large scale expression culture.To speed up the expression, we recommend the use of TB media warmed up to 37 degrees centigrade, which represents the temperature during the expression of the recombinant protein. Next, we add glucose to the TB media at a final concentration of oh 0.5%The glucose prevents an increased basal expression of the fusion protein during the growth of the expression culture before induction. Finally, ampicillin is added to the expression culture at a final concentration of 100 micrograms per ml to assure a pure culture only containing the bacteria which still harbor the plasmid encoding for decree protein.We now can get our overnight culture and inoculate the expression culture in the ratio of one to 50. The beakers then get transferred into an incubator running at the temperature of 37 centigrade. You should take samples to measure the optical density on a regular basis throughout the expression.As soon as the culture has reached an optical density of 1.5, the bacteria get induced with a final concentration of oh 0.5 millimolar of IPTG. After one hour of induction, the expression culture is transferred into tubings and subsequently harvested via centrifugation. For this purpose, we are using a SLA 3000 rotor.The centrifuge is running at a speed of 5, 000 round per minute for 10 minutes at four degrees antegrade. The snat then is discarded and the bacteria pellet can be stored indefinitely at minus 20 degree centigrade. The frozen pellets are resuspended in lizza buffer, a appellate corresponding to one liter of expression culture.We use 10 mls of lizza buffer wait approximately 15 minutes until the solution gets homogeneous. One milligram of lysozyme is then added per each ML of suspension. The solution is mixed for 20 minutes to allow the enzyme to break open the bacteria.Subsequently, Benson Nase is added in a dilution of one to 1000 for additional 15 minutes, which will cut the DNA resulting in a non viscous solution. Finally, a son ator is used to ensure lysis of the cells. The program is running for one and a half minutes with a power of 45%after completion of the certification.Remember to take a sample of every step here, the crude lysate or SDS page analysis of the purification. It is now really important to add one ml of ice cold TSB buffer per ML of suspension as decree protein will tend to precipitate within the glycerol stock. If you're going to skip this step, the solution gets mixed shortly and the crudely is now ready for centrifugation.For this purpose, we use a SS 34 rotor. The centrifuge is running at 17, 000 RPM for 30 minutes at four degree centigrade. When finished, centrifuge Inc carefully transferred the S supernatant into fresh 50 ml Falcon tubes.Now add nickel anti A slurry to the supernatant nickel. Anti A is a crucial reagent for the proper purification of the histidine tech fusion proteins. The histidine forms a complex with the nickel ions enabling affinity purification now gently shake the parking tubes for 60 minutes on 40 degree centigrade.After one hour, you now can apply the suspension onto 20 ML columns and allow the solution to run through by gravity flow. For large scale productions, it is feasible to split the suspension onto several columns. We then wash the column twice with a buffer containing 15 millimolar of innersole.The amount of buffer applied depends on the resin volume. Two MLS of nickel NTA correspond to one ml of resin for means of washing. We put five resin volumes of washing buffer onto the column after washing, we are now ready to elude our protein.Therefore, we use an elution buffer with a concentration of 250 millimolar of immuno. So notice how the color of the resin changes towards green. Due to the high concentrations of CRE protein, the OID fraction sometimes gets turd.To prevent this, mix the solution and add additional lys buffer, the all fractions are now getting pooled and subsequently transferred into a lysis tubing. Lysis will remove the ole first dialyzer step is performed against the buffer containing a high concentration of salt. After one hour, the high salt buffer is exchanged and dialyses procedure is applied overnight.The next day, the dialyses tubing is taken out of the high salt buffer and transferred into a glycerol buffer. After three to five hours, the glycerol buffer is exchanged and dialyses is again performed overnight. Lysis against glycerol buffer will result in an at least threefold concentrated stock solution.The stock solution can now be stored at minus 20 degrees centigrade for several years without the loss of activity For quality assurance, you can load your collected SDS page samples onto a gel and stain it subsequently. For Kamasi, the Cree fusion protein is detectable as a prominent band in the OID fraction. In order to use the appropriate concentration of crew recombination, you should determine the concentration via Redford assay.How to apply so permanent proteins into mammalian cells. First of all, prepare your target cells in order to achieve highest protein transduction efficiencies. See monolayer cells at the density resulting in the 80 to 90%confluence cell layer on the next day in case your target cells are yes cells, which are grown in compact colonies.Separate the cells and somatically and see them in a single cell suspension five hours in advance. It is important to make a single cell suspension prior to protein transduction because otherwise only air cells on the surface of a colony can be transfused. Aspire the media and watch the air cells briefly with PPS prior to tryin treatment.Remove remaining Yes, gross media containing serum. After aspirating the PPS overlay cells with dripping and let them incubate three to five minutes. Now check with the microscope if all colony comes are dissolved into single cells.The reasons just mentioned, this is a crucial step for protein transduction into yes cells. Transfer detached cells into a tube. Place the tube into a table, centrifuge and spin cells down, Aspirate the super agent and resuspend the cell.P in growth media dilute cells into appropriate cell number. That of course depends on the size of tissue culture. Dish incubate the air cells for additional five hours.This will give the air cells enough time to attach to the bottom and grow adherent. Three class row stock can be stored at minus 20 degrees for more than two years. When working with recombinant cell permanent fusion protein, it's very beneficial to have such a stock solution that can be used on demand.While waiting for the cells to attach to the dish, one can prepare the C transduction media simply dilute an appropriate volume of cell permanent creep protein from cholesterol stock into yourself.Media. Since the Clare stock solution is not yet sterile, trans media has to be sterile filtered prior to its application. We recommend using a syringe that can be screwed onto a lobe protein binding filter.The final creek concentration is dependent on cell type or media supplements. For example, serum has a strong negative influence on the transduction efficiency. This can be overcome by using serum free media or by an increased creek concentration.We find the optimal condition enabling highest recombination efficiency. Hydrate decree concentration starting from oh 0.5 up to 10 micromolar. We recommend testing different incubation times between six and 18 hours.After five hours of incubation, take out your target cells and aspirate cross media. Subsequently, we replace it with protein transduction media, put the air cells back into the incubator after overnight incubation. Briefly washed D cells with PPS and changed the protein transduction media to normal ES media.48 hours after the incubation of cell permanent Cree vent gene expression can be detected via xul. Staining cells with positive bega phenotype have successfully been genetically engineered by the site specific recombination. Cree the report.The cells harbor CRE use Lae construct upon pre mediad recombination. A lock P flank stop sequence is excised and a luxe reporter gene is activated driven by team promoter. In order to assess recombination efficiency in pre-treated reporter air cells cells have to be fixed.Aspirate s media wash cells twice with PBS overlay cells with 4%PFA and incubate cells for 10 minutes at room temperature. Thereafter wash cells once again three times with PBS. After aspirating the PBS from the last washing step at Xal Stain solution to the wells incubate cells overnight at 37 degrees in an incubator.On the next day, Beal activity can be monitored by blue collared cells. Recombination efficiency can be determined by the number of blue colonies. Under optimal conditions, you should be able to achieve a recombination efficiency higher than 90%Alright, today we have shown you how to express and purify site-specific query recombination From e coli.In this proof of principle study, we were able to induce recombination in most the salts. Okay, that's it. Good luck with your Experiments.I.

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A Functional Assay for Gap Junctional Examination; Electroporation of Adherent Cells on Indium-Tin Oxide

Electroporation was used to insert purified bacterial virulence effector proteins directly into living eukaryotic cells. Protein localization was monitored by confocal immunofluorescence microscopy. This method allows for studies on trafficking, function, and protein-protein interactions using active exogenous proteins, avoiding the need for heterologous expression in eukaryotic cells.

Electroporation of Functional Bacterial Effectors into Mammalian Cells

Here, we present a protocol to determine the orientation and topology of integral membrane proteins in living cells. This simple protocol relies on selective protease sensitivity of chimeras between the protein of interest and GFP.

Determining Membrane Protein Topology Using Fluorescence Protease Protection (FPP)

The presented protocol describes the analysis of membrane protein mediated transport on the single transporter level using pore-spanning solvent-free lipid bilayers. This is achieved by the creation of bulk produced nanopore array chips, combined with highly parallel data acquisition and analysis, enabling the future establishment of membrane protein effector screenings.

Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution

Two methods are presented here to determine intestinal barrier function. An epithelial meter (volt/ohm) is used for measurements of transepithelial electrical resistance of cultured epithelia directly in tissue culture wells. In mice, the FITC-dextran gavage method is used to determine the intestinal permeability in vivo.

In Vitro and In Vivo Approaches to Determine Intestinal Epithelial Cell Permeability

The fluorescence leakage assay is a simple method that enables the investigation of peptide/membrane interactions in order to understand their involvement in several biological processes and especially the ability of cell-penetrating peptides to disturb phospholipids bilayers during a direct cellular translocation process.

Fluorescent Leakage Assay to Investigate Membrane Destabilization by Cell-Penetrating Peptide

This protocol describes the microfabrication techniques required to build a lab-on-a-chip, microfluidic electroporation device. The experimental setup performs controlled, single-cell-level transfections in a continuous flow and can be extended to higher throughputs with population-based control. An analysis is provided showcasing the ability to electrically monitor the degree of cell membrane permeabilization in real-time.

The Fabrication and Operation of a Continuous Flow, Micro-Electroporation System with Permeabilization Detection

Porous substrate electroporation (PSEP) pairs consistent, high throughput delivery with high cell viability. Introduction of transepithelial electrical impedance (TEEI) measurements provides insight into the intermediate processes of PSEP and allows for label-free delivery. This article discusses a method for performing PSEP delivery experiments and TEEI measurement analysis simultaneously.

Porous Substrate-Based Electroporation with Transepithelial Electrical Impedance Monitoring

Learn protein transduction for delivering active proteins into mammalian cells using the Paciz vector system. This method enables efficient cellular manipulation without permanent genetic modification risks.

Engineering Cell-permeable Protein

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