Este trabalho foi financiado pelos Institutos Nacionais de Saúde (DP1CA174426 para Carlos F. Barbas) e da Universidade ShanghaiTech, Shanghai, China (a JL). Gráficos moleculares foram gerados utilizando pymol.

1. Clonagem <ol><li> Obter de dois dedos domínios ZIF substituído por alanina que foram sub-clonados no sistema de expressão vector pET-28 e estão disponíveis mediante pedido (PET-2F-ZiF). 34 </li><li> EmGFP amplificar por PCR a partir do plasmídeo pBAD-esmeralda com os iniciadores 5 &#39;Xmal-EmGFP (3-ATGGTGAGCAAGGGCGAGGAGCTGTTCAC 5&#39;-GGAAATTG CCCGGG&#39;; sítio Xmal em negrito) e 3 &#39;Saci-EmGFP (5&#39;-CGGATCT GAGCTC TTACTTGTACAGCTCGTCCATGCCGAG-3&#39; site eu Sac em negrito);. <ol><li> Use 5 ng de ADN molde, 10 ul de tampão de polimerase 10x, 1 Unidades (U) de Taq DNA polimerase, 0,2 mM de cada dNTP e 0,2 pM de cada iniciador numa solução de 100 uL com o restante volume constituídos de água destilada / desionizada . Use as condições dos ciclos: 95 ° C durante 5 min; 30 ciclos de 95 ° C durante 30 seg, 55 ° C durante 30 seg e 72 ° C durante 1 min; 72 ° C durante 10 min. Purifica-se o produto de PCR por gel extractie em determinar a concentração de ADN utilizando um espectrofotómetro de medição Abs 260 x 50 ug / ml. </li></ol></li><li> Digest pET-2F-ZiF e a inserção que codifica EmGFP com as enzimas de restrição Xmal e Sac I em tampão recomendado durante 3 horas a 37 ° C utilizando 10 U de enzima por 1 ug de ADN. Visualizar o ADN por electroforese em gel de agarose, utilizando um corante fluorescente intercalante, tal como brometo de etídio. </li><li> Purifica-se o ADN digerido por gel extraction kit e determinar a concentração de DNA por um espectrofotómetro Abs medindo 260 x 50 ug / ml. </li><li> Ligadura o ADN que codifica EmGFP purificado em 50-100 ng de pET-2F-ZiF usando 1 U de T4 DNA ligase durante pelo menos 1 h à TA. Para melhores resultados, realizar a reacção de ligação utilizando uma razão de 6: molar de inserção-para-um vector. </li><li> Descongelar 50 ul de quaisquer células XL-1 azul de E. coli quimicamente competentes de Escherichia em gelo e misturar suavemente com 10-20 ng de ligado pET-2F-ZiF-EmGFP. </li><li> Manter em gelo durante 30 min. O choque térmico a mistura a 42 ° C durante 90 seg e recuperar as células em 2 ml de caldo super óptima com repressão catabólica (SOC) durante 1 hora a 37 ° C com agitação. </li><li> Espalhe 100 ul de cultura de recuperação em um caldo lisogenia (LB) placa de ágar com 50 ug / ml de canamicina e incubar O / N a 37 ° C. </li><li> No dia seguinte, inocula 6 ml de Super Broth (SB) ou cultura LB contendo 50 ug / ml de canamicina com uma colónia da placa de agar LB e a cultura O / N a 37 ° C. Nota: Colony PCR utilizando os iniciadores 5 &#39;e Xmal-EmGFP 3&#39; Saci-EmGFP poderia ser usado para identificar os clones positivos antes de miniprep. </li><li> Purificar pET-2F-ZiF-EmGFP por miniprep e confirmar plasmídeo por sequenciação de ADN utilizando o promotor de T7 (5&#39;-TAATACGACTCACTATAGGG-3 &#39;). </li></ol> 2. Expressão e purificação <ol><li> Descongelar 50 ul de quimicamente competentes BL21 de E. coli células no gelo e misture delicadamente com 100 ng do PET-2F-ZiF-EmGFP plasmid. Transformação como descrito nos passos 1,7-1,8. </li><li> No dia seguinte, inocular 10 ml de meio LB contendo 50 ug / ml de canamicina com uma única colónia e crescer O / N a 37 ° C com agitação. </li><li> No dia seguinte, dilui-se os 10 ml da cultura D / N para 1 L de meio LB suplementado com 50 ug / ml de canamicina, 0,2% de glucose e 100 mM de ZnCl2. Crescer a cultura a 37 ° C com agitação até uma densidade óptica a 600 nm (OD 600) de 0,8 e induzir a expressão da proteína com 2 mM de isopropil-β-D-1-tiogalactopiranósido (IPTG). Após 6 horas de crescimento a 37 ° C, as células da colheita por centrifugação a 5000 xg durante 10 min a 4 ° C. Nota: As condições de indução são muito variáveis ​​e dependem da estabilidade das proteínas a ser expressa. Monitorar a OD a 600 a cada 30 min até uma DO600 de 0,8 seja alcançado. </li><li> Ressuspender o sedimento celular em 5 ml de tampão de lise (50 mM Tris-HCl, 500 mM de NaCl, 100 mM de ZnCl2, 1 mM ditiotreitol (DTT), 1 mM de MgCl 2, 1 mM de fluoreto de fenilmetilsulfonilo (PMSF) e 10 mM de imidazol, pH 8,0). Lisar as células no gelo por ultra-sons com a seguinte configuração: 50% de potência, 4 min de tempo de processo com 5 sec on / off intervalos de 10 segundos. Evitar o sobreaquecimento da solução. </li><li> Centrifuga-se o lisado celular a 25000 xg durante 30 min a 4 ° C e transferir o sobrenadante para um tubo de recolha de fresco. Para melhores resultados, executar todos os passos seguintes a 4 ° C. </li><li> Executar o sobrenadante através de uma coluna pré-embalada com 1 ml de suspensão equilibrada de Ni-NTA. Lava-se a resina com 20 ml de tampão de lavagem (50 mM Tris-HCl, 500 mM de NaCl, 100 fiM de ZnCl2, 1 mM de DTT, 1 mM de MgCl 2 e 30 mM de imidazol, pH 8,0). </li><li> Elui-se a proteína com 5 ml de tampão de eluição (50 mM Tris-HCl, 500 mM de NaCl, 100 fiM de ZnCl2, 1 mM de DTT, 1 mM de MgCl2, e 300 mM de imidazole, pH 8,0). </li><li> Tampão de trocar a proteína eluída com tampão de armazenamento (50 mMTris-HCl, 500 mM de NaCl, 100 mM de ZnCl2, 1 mM de DTT, 1 mM de MgCl2 e glicerol a 10%, pH 8,0) e concentrar a proteína de pelo menos 40 jiM utilizando um concentrador de rotação por centrifugação de acordo com as instruções do fabricante. </li><li> Determinar a concentração de proteína pelo ensaio de Bradford ou BCA. Misturar 2 ul de proteínas purificadas com 2 ul 2 × SDS-PAGE de corante de carga, ferver a 95 ° C durante 10 min e em seguida resolver a 4% -20% de Tris-Glicina SDS-PAGE para avaliar a pureza de proteína (Figura 2). </li></ol> 3. Proteína de armazenamento <ol><li> Alíquota da proteína concentrada, congelamento de flash em nitrogênio líquido e armazenar a -80 ° C. Para as proteínas de fusão EmGFP, cobrir o tubo com folha de alumínio para proteger a proteína da luz. </li><li> Evite congelamento e descongelamento da solução de proteína repetido. Nota: ZiF proteínas fundidas são estáveis ​​sob estas condições durante pelo menos 1 mês. Ou armazenamento inadequado mês&gt; 4 pode levara precipitação de proteínas ou de fotobranqueamento EmGFP. </li></ol> Transdução 4. Protein <ol><li> Manter as células HeLa em meio de Eagle modificado por Dulbecco (DMEM) contendo 10% (v / v) de soro fetal bovino (FBS) e 1% de antibiótico-antimicótico a 37 ° C em uma atmosfera totalmente humidi ficada com 5% de CO 2. Nota: As células passadas mais de 30 vezes não são recomendados para a transdução de proteína. </li><li> Pré-revestimento de uma placa de 24 poços com 500 ul de 50 ug / ml de poli-lisina para 30 a 60 min a 25 ° C. Semear as células num prato de 24 cavidades a uma densidade de 2 x 10 5 células por poço. Em 24 horas após a sementeira, ou uma vez que as células são entre 80% -90% confluentes, retirar o suporte de cada poço e lava-se com 500 ul de DMEM isento de soro pré-aquecido (SFM). </li><li> Para cada poço, adicione 250 mL de SFM contendo 2 uM de proteína ZiF-EmGFP e 100 uM de ZnCl2. Incubar as células a 37 ° C durante 1 h. Nota: domínios ZIF entrar nas células primarily através de macropinocitose, 34, o qual é um mecanismo dependente de energia. Portanto, as células devem ser incubados a 37 ° C durante internalização proteína eficiente. </li><li> Remover meios a partir de células e lava-se três vezes com 500 ul de cálcio e sem magnésio salina tamponada com fosfato de Dulbecco (DPBS) suplementado com 0,5 mg / ml de heparina. Nota: A heparina é necessário remover a proteína ligada à superfície que pode complicar análises a jusante. </li><li> (Opcional) tratamentos repetidos até três vezes para maior entrega. </li><li> Isolar células tratadas imediatamente depois de heparina de lavagem por digestão com 0,05% de tripsina-EDTA a 37 ° C durante 2 min. Re-suspender as células isoladas em 0,5 ml de DPBS suplementadas com 1% de FBS. </li><li> Medir a intensidade de fluorescência de cada amostra por 35 citometria de fluxo utilizando o isotiocianato de fluoresceína (FITC) canal (Figura 3). Ajuste a dispersão para a frente (FSC) e dispersão lateral (SSC) para colocar a população deinteresse na escala, assegurando que as populações com propriedades diferentes são resolvidos um do outro. </li><li> Colete 10.000 eventos ao vivo para cada amostra e analisar os dados utilizando citometria de fluxo de análise de dados software. 36 Normalize fluorescência de células HeLa tratadas com ZiF-EmGFP a essas células tratadas apenas com SFM. </li></ol>

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Aqui, um protocolo passo-a-passo para a entrega de proteína utilizando dedo de zinco (ZiF) domínios de células-permeável é apresentado. O domínio ZiF não reduz a atividade de carga enzimática fundido 34; permite a produção e purificação de proteínas em rendimentos quase idênticos aos observados com a proteína não modificada; e pode transportar proteínas e enzimas para uma ampla gama de tipos de células, com as eficiências que excedem os sistemas tradicionais de penetração de células de p...

Altamente estratégias de fornecimento de proteína eficientes e versáteis são críticos para muitos pesquisa básica e aplicações terapêuticas. A entrega directa das proteínas purificadas em células representa um dos métodos mais seguros e mais fáceis para alcançar este objectivo. 1,2 Ao contrário das estratégias que dependem de expressão de genes de ácidos nucleicos, 3-5 entrega proteína não apresenta nenhum risco de mutagénese de inserção, é independente do transcrição / máquinas e tradução celular permite um efeito imediato. No entanto, a falta de métodos simples e generalizáveis ​​para dotar a atividade de penetração celular para proteínas confunde rotineiramente sua entrada direta nas células. Os métodos actuais para facilitar a entrega intracelular de proteínas são baseadas no uso de ocorrência natural ou 6-8 concebidos de penetração de células, péptidos 9-12 domínios de transdução de sobrealimentação, 13,14 nanopartículas 15, 16 e lipossomas partículas semelhantes a vírus 17,18 </sup&gt; e materiais de microesferas poliméricas. 19 Infelizmente, muitas dessas abordagens são dificultados pelas taxas de captação celular baixos, 20,21 pobre estabilidade, 22 inadvertida tipo de célula de especificidade, 23 propriedades de escape baixo endossomais 24 e toxicidade. 25 Além disso, muitos proteína tecnologias de transdução de reduzir a bioactividade das proteínas entregues 14. O nosso laboratório demonstrou anteriormente que zinc-finger nuclease proteínas (ZFN) - endonucleases de restrição quimérico que consiste de uma Cys His 2 2 zinc-finger programável proteína de ligação a ADN e domínio de clivagem da endonuclease de restrição FokI 26-28 - são inerentemente célula.dia permeável. 29 Esta actividade de penetração celular surpreendente mostrou ser uma propriedade intrínseca do domínio dedo-de-zinco personalizados, com uma plataforma de ligação de ADN que surgiu como uma ferramenta poderosa para o genoma segmentado enengenha-, 30-32 e ser considerada como o resultado da constelação de seis resíduos carregados positivamente na superfície da proteína. De facto, várias proteínas de ligação de ADN, incluindo c-Jun e N-DEK foram mostrados para possuir uma capacidade inata para atravessar as membranas celulares. 33 Mais recentemente, no nosso laboratório expandido estes resultados e demonstraram que a actividade da célula de penetração de zinco finger (ZIF) da domínios poderia ser aproveitado para a entrega de proteínas intracelulares. Fusão genética de ambos domínios ZIF de um ou dois dedos para carga proteína específica levou a absorção eficiências que superaram muitos sistemas de entrega de peptídeos convencionais de penetração celular. 34 Mais notavelmente, entrega ZiF mediada não comprometeu a atividade de carga enzimática fundido e facilitado altos níveis de entrega cytosolic. Colectivamente, estes resultados demonstram o potencial do domínio ZiF para facilitar a entrega eficiente e fácil de proteínas, e potencialmente mais diversos tipos de macromoléculas, em células. Aqui, um protocolo detalhado passo-a-passo sobre como implementar a tecnologia ZiF para entrega de proteína em células de mamíferos é apresentada. Nós previamente construído um conjunto de um, dois, três, quatro, cinco e seis domínios dedo-Zif que não possuem a capacidade de se ligar ao ADN, devido a substituição de cada um dos resíduos de ligação ao ADN de hélice α, mas são capazes de fornecer proteínas em células 34 (Figura 1). A produção e a transdução de esmeralda GFP (EmGFP) em células HeLa usando um domínio ZiF de dois dedos é descrito. Este protocolo é extensível para quase qualquer proteína solúvel capaz de expressão em Escherichia coli e quase qualquer tipo de células de mamíferos. Os resultados esperados são fornecidos e estratégias para maximizar o desempenho do sistema também são discutidos.

<table><tbody><tr><td>XmaI</td><td>New England Biolabs</td><td>R0180L</td><td></td></tr><tr><td>SacI</td><td>New England Biolabs</td><td>R0156L</td><td></td></tr><tr><td>Expand High Fidelity PCR system</td><td>Roche</td><td>11759078001</td><td></td></tr><tr><td>dNTPs</td><td>New England Biolabs</td><td>N0446S</td><td></td></tr><tr><td>4%-20% Tris-Glycine Mini protein gels, 1.5 mm, 10 wells</td><td>Life Technologies</td><td>EC6028BOX</td><td></td></tr><tr><td>2x Laemmli Sample Buffer</td><td>BioRad</td><td>161-0737</td><td></td></tr><tr><td>T4 DNA Ligase</td><td>Life Technologies</td><td>15224-017</td><td></td></tr><tr><td>BL21 (DE3) Competent &lt;em&gt;E. coli&lt;/em&gt;</td><td>New England Biolabs</td><td>C2527I</td><td></td></tr><tr><td>IPTG</td><td>Thermo Scientific</td><td>R0391</td><td></td></tr><tr><td>Zinc Chloride</td><td>Sigma-Aldrich</td><td>208086-5G</td><td></td></tr><tr><td>Kanamycin Sulfate</td><td>Fisher Scientific</td><td>BP906-5</td><td></td></tr><tr><td>Glucose</td><td>Sigma-Aldrich</td><td>G8270-100G</td><td></td></tr><tr><td>Tris Base</td><td>Fisher Scientific</td><td>BP152-25</td><td></td></tr><tr><td>Sodium Chloride</td><td>Sigma-Aldrich</td><td>S9888-25G</td><td></td></tr><tr><td>DTT</td><td>Fisher Scientific</td><td>PR-V3151&amp;nbsp;</td><td></td></tr><tr><td>PMSF</td><td>Thermo Scientific</td><td>36978</td><td></td></tr><tr><td>Ni-NTA Agarose Resin</td><td>QIAGEN</td><td>30210</td><td></td></tr><tr><td>Glycerol</td><td>Sigma-Aldrich</td><td>G5516-500ML</td><td></td></tr><tr><td>Imidazole</td><td>Sigma-Aldrich</td><td>I5513-25G</td><td></td></tr><tr><td>Amicon Ultra-15 Centrifugal Filter Units</td><td>EMO Millipore</td><td>UFC900324</td><td></td></tr><tr><td>DMEM</td><td>Life Technologies</td><td>11966-025</td><td></td></tr><tr><td>Fetal Bovine Serum</td><td>Life Technologies</td><td>10437-028</td><td></td></tr><tr><td>Antibiotic-Antimycotic&amp;nbsp;</td><td>Life Technologies</td><td>15240-062</td><td></td></tr><tr><td>24-Well Flat Bottom Plate</td><td>Sigma-Aldrich</td><td>CLS3527-100EA</td><td></td></tr><tr><td>Poly-Lysine</td><td>Sigma-Aldrich</td><td>P7280</td><td></td></tr><tr><td>DPBS, No Calcium, No Magnesium</td><td>Life Technologies</td><td>21600010</td><td></td></tr><tr><td>Heparan Sulfate</td><td>Sigma-Aldrich</td><td>H4777</td><td></td></tr><tr><td>Trypsin</td><td>Life Technologies</td><td>25300054</td><td></td></tr><tr><td>HeLa cells</td><td>ATCC</td><td>CCL-2</td><td></td></tr><tr><td>Nano Drop ND-1000 spectrophotometer&amp;nbsp;</td><td>Thermo Fisher Scientific</td><td></td><td></td></tr><tr><td>QIAquick PCR Purification Kit</td><td>QIAGEN</td><td>28104</td><td></td></tr><tr><td>QIAquick Gel Extraction Kit</td><td>QIAGEN</td><td>28704</td><td></td></tr></tbody></table>

direct protein delivery to mammalian cells using cell-permeable cys2-his2 zinc-finger domains

Due to their modularity and ability to be reprogrammed to recognize a wide range of DNA sequences, Cys2-His2 zinc-finger DNA-binding domains have emerged as useful tools for targeted genome engineering. Like many other DNA-binding proteins, zinc-fingers also possess the innate ability to cross cell membranes. We recently demonstrated that this intrinsic cell-permeability could be leveraged for intracellular protein delivery. Genetic fusion of zinc-finger motifs leads to efficient transport of protein and enzyme cargo into a broad range of mammalian cell types. Unlike other protein transduction technologies, delivery via zinc-finger domains does not inhibit enzyme activity and leads to high levels of cytosolic delivery. Here a detailed step-by-step protocol is presented for the implementation of zinc-finger technology for protein delivery into mammalian cells. Key steps for achieving high levels of intracellular zinc-finger-mediated delivery are highlighted and strategies for maximizing the performance of this system are discussed.

Dois dedos de proteínas de fusão ZiF-EmGFP pode ser expresso em E. coli com&gt; 95% de homogeneidade e rendimentos elevados (&gt; 25 mg / ml) (Figura 2). Em geral, de um e de dois dedos proteínas de fusão ZiF pode ser produzido em quantidades quase idênticas às de proteína não modificada tipo selvagem. No entanto, em alguns contextos, as proteínas de fusão ZiF cinco e seis dedos não são capazes de ser produzidos em rendimentos elevados o suficiente para aplicações a jusante. <...

Watch this Scientific Journal Video about Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains at JoVE.com

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains

Domínios dedo-de-zinco são intrinsecamente célula-permeável e capaz de mediar a entrega de proteína em uma ampla gama de tipos de células de mamíferos. Aqui, um protocolo detalhado passo-a-passo para a implementação da tecnologia de dedo de zinco para a entrega intracelular de proteínas é apresentada.

Entrega Protein direto para células de mamíferos utilizando células-permeável Cys<sub&gt; 2</sub&gt; -His<sub&gt; 2</sub&gt; Domínios zinc-finger

Due to their modularity and ability to be reprogrammed to recognize a wide range of DNA sequences, Cys2-His2 zinc-finger DNA-binding domains have emerged ...

direct-protein-delivery-to-mammalian-cells-using-cell-permeable-cys2

Research

JoVE Journal

Biology

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains

9.9K visualizações.  The Scripps Research Institute.  Domínios dedo-de-zinco são intrinsecamente célula-permeável e capaz de mediar a entrega de proteína em uma ampla gama de tipos de células de mamíferos. Aqui, um protocolo detalhado passo-a-passo para a implementação da tecnologia de dedo de zinco para a entrega intracelular de proteínas é apresentada. 

Vídeo: Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains

Peptide-derived Method to Transport Genes and Proteins Across Cellular and Organellar Barriers in Plants

The capacity to introduce exogenous proteins and express (or down-regulate) specific genes in plants provides a powerful tool for fundamental research as well as new applications in the field of plant biotechnology. Viable methods that currently exist for protein or gene transfer into plant cells, namely Agrobacterium and microprojectile bombardment, have disadvantages of low transformation frequency, limited host range, or a high cost of equipment and microcarriers. The following protocol outlines a simple and versatile method, which employs rationally-designed peptides as delivery agents for a variety of nucleic acid- and protein-based cargoes into plants. Peptides are selected as tools for development of the system due to their biodegradability, reduced size, diverse and tunable properties as well as the ability to gain intracellular/organellar access. The preparation, characterization and application of optimized formulations for each type of the wide range of delivered cargoes (plasmid DNA, double-stranded DNA or RNA, and protein) are described. Critical steps within the protocol, possible modifications and existing limitations of the method are also discussed.

Existing methods for the modification of plants have limited applicability. The novel peptide-derived technology proposed here promises both simplicity and efficiency in the introduction of exogenous protein or genes into the desired intracellular compartments of intact plants.

Peptídeo derivado Método para Transporte genes e proteínas Através Celular e Barreiras organelares em plantas

The capacity to introduce exogenous proteins and express (or down-regulate) specific genes in plants provides a powerful tool for fundamental research as ...

Genética

Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions

Here we present a protocol to study intracellular protein-protein interactions that is based on the widely used biotin-avidin pull-down system. The modification presented includes the combination of this technique with cell-penetrating sequences. We propose to design cell-penetrating baits that can be incubated with living cells instead of cell lysates and therefore the interactions found will reflect those that occur within the intracellular context. Connexin43 (Cx43), a protein that forms gap junction channels and hemichannels is down-regulated in high-grade gliomas. The Cx43 region comprising amino acids 266-283 is responsible for the inhibition of the oncogenic activity of c-Src in glioma cells. Here we use TAT as the cell-penetrating sequence, biotin as the pull-down tag and the region of Cx43 comprised between amino acids 266-283 as the target to find intracellular interactions in the hard-to-transfect human glioma stem cells. One of the limitations of the proposed method is that the molecule used as bait could fail to fold properly and, consequently, the interactions found could not be associated with the effect. However, this method can be especially interesting for the interactions involved in signal transduction pathways because they are usually carried out by intrinsically disordered regions and, therefore, they do not require an ordered folding. In addition, one of the advantages of the proposed method is that the relevance of each residue on the interaction can be easily studied. This is a modular system; therefore, other cell-penetrating sequences, other tags, and other intracellular targets can be employed. Finally, the scope of this protocol is far beyond protein-protein interaction because this system can be applied to other bioactive cargoes such as RNA sequences, nanoparticles, viruses or any molecule that can be transduced with cell-penetrating sequences and fused to pull-down tags to study their intracellular mechanism of action.

This is a protocol to study intracellular protein-protein interactions based on the biotin-avidin pull-down system with the novelty of combining cell-penetrating sequences. The main advantage is that the target sequence is incubated with living cells instead of cell lysates and therefore the interactions will occur within the cellular context.

Peptídeos biotinylated célula-penetrante para estudar interações da proteína-proteína intracelular

Here we present a protocol to study intracellular protein-protein interactions that is based on the widely used biotin-avidin pull-down system. The ...

Bioquímica

Cell Squeezing as a Robust, Microfluidic Intracellular Delivery Platform

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This technology has shown potential in addressing previously challenging applications; including, delivery to primary immune cells, cell reprogramming, carbon nanotube, and quantum dot delivery. This vector-free microfluidic platform relies on mechanical disruption of the cell membrane to facilitate cytosolic delivery of the target material. Herein, we describe the detailed method of use for these microfluidic devices including, device assembly, cell preparation, and system operation. This delivery approach requires a brief optimization of device type and operating conditions for previously unreported applications. The provided instructions are generalizable to most cell types and delivery materials as this system does not require specialized buffers or chemical modification/conjugation steps. This work also provides recommendations on how to improve device performance and trouble-shoot potential issues related to clogging, low delivery efficiencies, and cell viability.

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This protocol provides detailed steps on how to use the system for a broad range of applications.

Espremendo celular como uma plataforma de entrega intracelular Robust Microfluidic

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This ...

Bioengenharia

Engineering Intracellular Protein Sensors in Mammalian Cells

Proteins can function as biomarkers of pathological conditions, such as neurodegenerative diseases, infections or metabolic syndromes. Engineering cells to sense and respond to these biomarkers may help the understanding of molecular mechanisms underlying pathologies, as well as to develop new cell-based therapies. While several systems that detect extracellular proteins have been developed, a modular framework that can be easily re-engineered to sense different intracellular proteins was missing.
Here, we describe a protocol to implement a modular genetic platform that senses intracellular proteins and activates a specific cellular response. The device operates on intracellular antibodies or small peptides to sense with high specificity the protein of interest, triggering the transcriptional activation of output genes, through a TEV protease (TEVp)-based actuation module. TEVp is a viral protease that selectively cleaves short cognate peptides and is widely used in biotechnology and synthetic biology for its high orthogonality to the cleavage site. Specifically, we engineered devices that recognize and respond to protein-biomarkers of viral infections and genetic diseases, including mutated huntingtin, NS3 serine-protease, Tat and Nef proteins to detect Huntington&#8217;s disease, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections, respectively. Importantly, the system can be hand tailored for the desired input-output functional outcome, such as fluorescent readouts for biosensors, stimulation of antigen presentation for immune response, or initiation of apoptosis to eliminate unhealthy cells.

<meta charset="utf8"></head><body>Engenharia de sensores de proteínas intracelulares em células de mamíferos

Here, we present a protocol for engineering genetically-encoded intracellular protein sensor-actuator(s). The device specifically detects target proteins through intracellular antibodies (intrabodies) and responds by switching on gene transcriptional output. A general framework is built to rapidly replace intrabodies, enabling rapid detection of any desired protein, without altering the general architecture.

Engenharia de sensores de proteínas intracelulares em células de mamíferos

Proteins can function as biomarkers of pathological conditions, such as neurodegenerative diseases, infections or metabolic syndromes. Engineering cells ...

Delivery of Proteins, Peptides or Cell-impermeable Small Molecules into Live Cells by Incubation with the Endosomolytic Reagent dfTAT

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the efficiency with which macromolecules penetrate the cytosolic space of cells. Recently, we have circumvented this problem by identifying the reagent dfTAT, a disulfide bond dimer of the peptide TAT labeled with the fluorophore tetramethylrhodamine. We have generated a fluorescently labeled dimer of the prototypical cell-penetrating peptide (CPP) TAT, dfTAT, which penetrates live cells and reaches the cytosolic space of cells with a particularly high efficiency. Cytosolic delivery of dfTAT is achieved in multiple cell lines, including primary cells. Moreover, delivery does not noticeably impact cell viability, proliferation or gene expression. dfTAT can deliver small molecules, peptides, antibodies, biologically active enzymes and a transcription factor. In this report, we describe the protocols involved in dfTAT synthesis and cellular delivery. The manuscript describes how to control the amount of protein delivered to the cytosolic space of cells by varying the amount of protein administered extracellularly. Finally, the current limitations of this new technology and steps involved in validating delivery are discussed. The described protocols should be extremely useful for cell-based assays as well as for the ex vivo manipulation and reprogramming of cells.

We describe how to deliver proteins and cell-impermeable small molecules into cultured mammalian cells by a simple co-incubation protocol with a reagent that causes endocytic organelles to become leaky.

Entrega de proteínas, peptídeos ou célula-impermeável Pequenas moléculas em células vivas por incubação com o Endosomolytic Reagente dfTAT

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the ...

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.

Engenharia de Proteínas Cell-permeáveis

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

Biologia

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

Recombinant protein expression in bacteria, typically E. coli, has been the most successful strategy for milligram quantity expression of proteins. However, prokaryotic hosts are often not as appropriate for expression of human, viral or eukaryotic proteins due to toxicity of the foreign macromolecule, differences in the protein folding machinery, or due to the lack of particular co- or post-translational modifications in bacteria. Expression systems based on yeast (P. pastoris or S. cerevisiae) 1,2, baculovirus-infected insect (S. frugiperda or T. ni) cells 3, and cell-free in vitro translation systems 2,4 have been successfully used to produce mammalian proteins. Intuitively, the best match is to use a mammalian host to ensure the production of recombinant proteins that contain the proper post-translational modifications. A number of mammalian cell lines (Human Embryonic Kidney (HEK) 293, CV-1 cells in Origin carrying the SV40 larget T-antigen (COS), Chinese Hamster Ovary (CHO), and others) have been successfully utilized to overexpress milligram quantities of a number of human proteins 5-9. However, the advantages of using mammalian cells are often countered by higher costs, requirement of specialized laboratory equipment, lower protein yields, and lengthy times to develop stable expression cell lines. Increasing yield and producing proteins faster, while keeping costs low, are major factors for many academic and commercial laboratories.
Here, we describe a time- and cost-efficient, two-part procedure for the expression of secreted human proteins from adherent HEK 293T cells. This system is capable of producing microgram to milligram quantities of functional protein for structural, biophysical and biochemical studies. The first part, multiple constructs of the gene of interest are produced in parallel and transiently transfected into adherent HEK 293T cells in small scale. The detection and analysis of recombinant protein secreted into the cell culture medium is performed by western blot analysis using commercially available antibodies directed against a vector-encoded protein purification tag. Subsequently, suitable constructs for large-scale protein production are transiently transfected using polyethyleneimine (PEI) in 10-layer cell factories. Proteins secreted into litre-volumes of conditioned medium are concentrated into manageable amounts using tangential flow filtration, followed by purification by anti-HA affinity chromatography. The utility of this platform is proven by its ability to express milligram quantities of cytokines, cytokine receptors, cell surface receptors, intrinsic restriction factors, and viral glycoproteins. This method was also successfully used in the structural determination of the trimeric ebolavirus glycoprotein 5,10.
In conclusion, this platform offers ease of use, speed and scalability while maximizing protein quality and functionality. Moreover, no additional equipment, other than a standard humidified CO2 incubator, is required. This procedure may be rapidly expanded to systems of greater complexity, such as co-expression of protein complexes, antigens and antibodies, production of virus-like particles for vaccines, or production of adenoviruses or lentiviruses for transduction of difficult cell lines.

In the post-human genomics era, the availability of recombinant proteins in native conformations is crucial to structural, functional and therapeutic research and development. Here, we describe a test- and large-scale protein expression system in human embryonic kidney 293T cells that can be used to produce a variety of recombinant proteins.

A Plataforma de expressão adequada e geral para a produção de proteínas secretadas a partir de células humanas

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

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.

Expressão de proteínas recombinantes de Biologia Estrutural em HEK 293F Suspensão Cells: Uma abordagem inovadora e acessível

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

A High Yield and Cost-efficient Expression System of Human Granzymes in Mammalian Cells

When cytotoxic T lymphocytes (CTL) or natural killer (NK) cells recognize tumor cells or cells infected with intracellular pathogens, they release their cytotoxic granule content to eliminate the target cells and the intracellular pathogen. Death of the host cells and intracellular pathogens is triggered by the granule serine proteases, granzymes (Gzms), delivered into the host cell cytosol by the pore forming protein perforin (PFN) and into bacterial pathogens by the prokaryotic membrane disrupting protein granulysin (GNLY). To investigate the molecular mechanisms of target cell death mediated by the Gzms in experimental in-vitro settings, protein expression and purification systems that produce high amounts of active enzymes are necessary. Mammalian secreted protein expression systems imply the potential to produce correctly folded, fully functional protein that bears posttranslational modification, such as glycosylation. Therefore, we used a cost-efficient calcium precipitation method for transient transfection of HEK293T cells with human Gzms cloned into the expression plasmid pHLsec. Gzm purification from the culture supernatant was achieved by immobilized nickel affinity chromatography using the C-terminal polyhistidine tag provided by the vector. The insertion of an enterokinase site at the N-terminus of the protein allowed the generation of active protease that was finally purified by cation exchange chromatography. The system was tested by producing high levels of cytotoxic human Gzm A, B and M and should be capable to produce virtually every enzyme in the human body in high yields.

We describe here a cost-efficient granzyme expression system using HEK293T cells that produces high yields of pure, fully glycosylated and enzymatically active protease.

A High Yield e custo-eficiente sistema de expressão de Granzimas Humanos em células de mamíferos

When cytotoxic T lymphocytes (CTL) or natural killer (NK) cells recognize tumor cells or cells infected with intracellular pathogens, they release their ...

Entrega Protein direto para células de mamíferos utilizando células-permeável Cys

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