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Ingegneria proteina ricombinante è una tecnica molto potente che abbraccia molte discipline. Si è costo-efficace, regolabile e una procedura relativamente semplice, consentendo la produzione di alte rese di proteine ​​personalizzati. È importante notare che la progettazione ed esprimere proteine ​​bersaglio non è sempre semplice. Espressione basale e la stabilità della proteina ricombinante dipendono da specifiche scelte di vettore, E. coli cellulari, peptide tag aggiunte e parametri colturali. Il ...

Proteine ​​coprono una vasta gamma di biomolecole che sono responsabili di molte funzioni biologiche, portando in definitiva a formazione di tessuto corretto e organizzazione. Queste molecole iniziano migliaia di vie di segnalazione che controllano up-regulation e / o down-regolazione dei geni e delle altre proteine, mantenendo l&#39;equilibrio all&#39;interno del corpo umano. Rottura di una singola proteina colpisce tutta questa rete di segnali, che può portare alla comparsa di disturbi o malattie devastanti. Ingegneria singole proteine ​​in laboratorio offre una soluzione per la lotta contro questi effetti collaterali e offre un&#39;alternativa ai farmaci a piccole molecole. Nel 1977, un gene che codifica la sequenza amminoacidica somatostatina 14 è stato uno dei primi polipeptidi ingegnerizzati creati utilizzando E. coli 1. Poco dopo, nel 1979, l&#39;insulina è stato clonato in plasmide pBR322, trasformato, espresso e purificato 2. Da allora, proteine ​​ricombinanti hanno esteso la loro influenza per più campi di research come biomateriali, drug delivery, l&#39;ingegneria dei tessuti, prodotti biofarmaceutici, agricoltura, enzimi industriali, biocarburanti, ecc (per una rassegna vedi riferimenti 3-8). Ciò è dovuto alla versatilità che la tecnica offre tramite l&#39;aggiunta di applicazioni porzioni chimiche specifiche o sequenze proteiche per scopi che includono, ma non limitato a, l&#39;identificazione delle proteine ​​bersaglio, stabilizzazione e purificazione. Tramite la tecnologia del DNA ricombinante, proteine ​​ricombinanti possono essere espressi in una varietà di sistemi ospite eucariotiche e procariotiche inclusi mammiferi, insetti, piante, lieviti, funghi o batteri. Ogni host offre diversi vantaggi e tipicamente il miglior sistema è determinato sulla base della funzione della proteina, resa, stabilità, costi complessivi e scalabilità. Cellule dei batteri spesso mancano i meccanismi di modificazione post-traslazionale che ospita eucariotiche forniscono (ad esempio la glicosilazione, disolfuro di transizione, e<html> tc.) 5. Di conseguenza, i sistemi di mammiferi e insetti solito risultato migliore compatibilità e l&#39;espressione di proteine ​​eucariotiche, tuttavia questi host sono generalmente più costosi e 9 richiede tempo. Pertanto, E. coli è l&#39;ospite privilegiato per il nostro sistema di espressione perché le cellule si espandono rapidamente in condizioni di crescita economici ed i meccanismi di espressione genetica sono ben compresi 5,9. Inoltre, questo sistema è facile da scalare, per scopi produttivi e dei risultati in proteine ​​funzionali nonostante la mancanza di modificazioni post-traslazionali 10. Il E. coli K12 è scelto in questo protocollo per la clonazione, perché questo ceppo offre ottimi rendimenti plasmide basato su alte efficienze di trasformazione. Inoltre, un E. coli BL21 è utilizzato per l&#39;espressione perché questo ceppo ospite contiene il gene della polimerasi T7 RNA che fornisce l&#39;espressione proteica controllata e stabilità 11. tenda &quot;&gt; Dopo la selezione ospitante, inoltre bisogna fare attenzione nella scelta del vettore di espressione ideale per facilitare l&#39;espressione della proteina selezionata e controllata. Sintetizzando proteine ​​ricombinanti inizia con una sequenza di DNA bersaglio che è clonato sotto la direzione del batteriofago T7 trascrizione e traduzione segnali, e espressione viene indotta in cellule ospiti contenenti copie cromosomiche del gene T7 RNA polimerasi 12. Questi vettori derivati ​​da pBR322 plasmide vettore (per una rassegna vedi riferimento 13), sono strettamente controllato dal promotore T7 sviluppato inizialmente da Studier e colleghi 14 e fornire ulteriori controllo attraverso l&#39;inclusione dell&#39;operatore lac e repressore lac (lac1) 15,16. Per ingegneria proteica ricombinante, questo sistema di espressione offre la possibilità di personalizzare una specifica sequenza amminoacidica di una proteina desiderata inserendo diverse sequenze di DNA bersaglio o per creare proteine ​​di fusione costituiti di dominio combinatos da singole proteine. Inoltre, alcune serie vettore comprendono peptide modifiche tag per essere immessi sul N o C terminus. Per i nostri scopi di progettazione, una istidina (His) tag è stato aggiunto alla sequenza bersaglio di DNA per la purificazione e una sequenza amminoacidica biotinylatable 15 è stato incluso per biotinylation 17,18. In questo protocollo un plasmide contenente un gene di resistenza all&#39;ampicillina, è stato scelto per portare le sequenze di proteine ​​di fusione biotinylatable. Espressione è controllata in questo vettore tramite il T7 promotore lac ed è facilmente indotta con isopropil β-D-1-thiogalactopyranoside (IPTG). Espressioni di prova (colture su piccola scala) vengono utilizzati per determinare la presenza e la solubilità della proteina bersaglio, che può essere espresso sia in una forma solubile o insolubile formulare procedure di purificazione. Una proteina solubile espressa all&#39;interno della cellula batterica subirà pieghevole spontanea di mantenere la sua struttura nativa 19. Tipicamente il nativostruttura è termodinamicamente favorevole. In molti casi l&#39;attività metabolica dell&#39;ospite non è favorevole alla proteina bersaglio, ponendo sollecitazioni al sistema che porta alla produzione di proteine ​​insolubili e la formazione di corpi di inclusione composti di aggregati proteici insolubili. Così la proteina bersaglio denatura, rendendoli generalmente biologicamente inattivo 20. Entrambe le espressioni di prova sono scalati-up, e procedure di isolamento sono determinate dalla solubilità della proteina bersaglio. È necessaria una rinaturazione supplementare o ripiegamento passo per le proteine ​​insolubili. Le proteine ​​ricombinanti risultanti possono essere ulteriormente purificati mediante cromatografia ad esclusione dimensionale. In casa produzione di proteine ​​ricombinanti offre vantaggi economici rispetto ai prodotti commerciali dal milligrammi di proteina bersaglio possono essere isolati per litro di coltura principale. La maggior parte delle attrezzature necessarie è disponibile in un tipico laboratorio biologico o chimico. Ingegneria proteica consente la creazionedi proteine ​​di fusione personalizzato con ulteriori funzionalità che non sempre sono disponibili in commercio. figura 1 illustra i principali procedure necessarie proteine ​​ricombinanti ingegneria. Con questo sistema di espressione abbiamo creato molte proteine ​​biotinylatable, come l&#39;interferone-gamma, fattore di crescita derivato dalle piastrine, e la proteina morfogenetica dell&#39;osso, 21-23, ma ci concentreremo su due proteine ​​che abbiamo progettato per la guida degli assoni, NGF (29 kDa ) e Sema3A (91 kDa) 10 (per una rassegna vedi riferimento 24). Biotinylation è una tecnica comune per l&#39;identificazione, immobilizzazione e l&#39;isolamento di proteine ​​marcate utilizzando il noto interazione biotina-streptavidina 25-27. Sonde biofisiche 28,29, biosensori 30 e 31 punti quantici sono alcuni esempi di sistemi che utilizzano l&#39;alta affinità della biotina-streptavidina coniugazione con una K d dell&#39;ordine di 10 -15 M 27. Il E. bio coliligasi stagno, Bira, aiuti nel legame covalente di biotina alla catena laterale di lisina trovati all&#39;interno della biotina etichettato sequenza di 18,32. Tethering biotina ai materiali e biomolecole ha prodotto la consegna sostenuto di fattori di crescita per cellulare per molteplici applicazioni di ingegneria tissutale 21,33-35. Pertanto, ingegneria queste proteine ​​biotinylatable progettati su misura è un potente strumento che può trascendere molteplici interessi di ricerca.

<table><tbody><tr><td>1,4-Dithio-DL-threitol, DTT, 99.5%</td><td>Chem-Impex International</td><td>127</td><td>100 g</td></tr><tr><td>2-Hydroxyethylmercaptan &amp;beta;-Mercaptoethanol</td><td>Chem-Impex International</td><td>642</td><td>250 ml</td></tr><tr><td>Acetic acid, glacial</td><td>EMD</td><td>AX0073-9</td><td>2.5 L</td></tr><tr><td>Agar</td><td>Bioshop</td><td>AGR001.500</td><td>500 g</td></tr><tr><td>Ampicillin sodium salt&amp;nbsp;</td><td>Sigma-Aldrich</td><td>A9518</td><td>25 g</td></tr><tr><td>Antifoam 204</td><td>Sigma-Aldrich</td><td>A6426</td><td>500 g</td></tr><tr><td>Barstar-NGF pET-21a(+)</td><td>GenScript USA Inc.</td><td></td><td>4 &amp;micro;g</td></tr><tr><td>BL21(DE3) Competent Cells</td><td>Novagen</td><td>69450</td><td>1 ml; Expression Host</td></tr><tr><td>Bradford reagent</td><td>Sigma-Aldrich</td><td>B6916</td><td>500 ml</td></tr><tr><td>BugBuster</td><td>Novagen</td><td>70922-3</td><td>100 ml</td></tr><tr><td>Gel filtration standard</td><td>Bio-Rad</td><td>151-1901</td><td>6 vials</td></tr><tr><td>Glycerol</td><td>Bioshop</td><td>GLY001.1</td><td>1 L</td></tr><tr><td>Guanidine hydrodioride amioformamidine hydrochloride</td><td>Chem-Impex International</td><td>152</td><td>1 kg</td></tr><tr><td>His-Pur Ni-NTA Resin</td><td>Thermo Scientific</td><td>88222</td><td>100 ml</td></tr><tr><td>Hydrochloric acid</td><td>EMD</td><td>HX0603-3</td><td>2.5 L</td></tr><tr><td>Imidazole&amp;nbsp;</td><td>Chem-Impex International</td><td>418</td><td>250 g</td></tr><tr><td>IPTG</td><td>Chem-Impex International</td><td>194</td><td>100 g</td></tr><tr><td>Laemmli sample buffer</td><td>Bio-Rad</td><td>161-0737</td><td>30 ml</td></tr><tr><td>Lauryl sulfate sodium salt, Sodium dodecyl surface</td><td>Chem-Impex International</td><td>270</td><td>500 g</td></tr><tr><td>LB Broth&amp;nbsp;&amp;nbsp;</td><td>Sigma-Aldrich</td><td>L3022</td><td>1 kg</td></tr><tr><td>NovaBlue Competent Cells</td><td>Novagen</td><td>69825</td><td>1 ml; Cloning Host</td></tr><tr><td>Phosphate buffered saline</td><td>Sigma-Aldrich</td><td>P5368-10PAK</td><td>10 pack</td></tr><tr><td>Potassium Chloride</td><td>Chem-Impex International</td><td>01247</td><td>1 kg</td></tr><tr><td>Sema3A-pET-21a(+)</td><td>GenScript USA Inc.</td><td></td><td>4 &amp;micro;g</td></tr><tr><td>SimplyBlue SafeStain</td><td>Invitrogen</td><td>LC6060</td><td>1 L</td></tr><tr><td>Sodium chloride</td><td>Sigma-Aldrich</td><td>S5886-1KG</td><td>1 kg</td></tr><tr><td>Sodium hydroxide</td><td>Fisher Scientific</td><td>S318-500</td><td>500 g</td></tr><tr><td>Sodium phosphate diabasic</td><td>Sigma-Aldrich</td><td>S5136-500G</td><td>500 g</td></tr><tr><td>Sodium phosphate monobasic</td><td>Sigma-Aldrich</td><td>S5011</td><td>500 g</td></tr><tr><td>Terrific Broth</td><td>Bioshop</td><td>TER409.5</td><td>5 kg</td></tr><tr><td>Tetracycline hydrochloride</td><td>Chem-Impex International</td><td>667</td><td>25 g</td></tr><tr><td>Tris/Glycine/SDS Buffer, 10x</td><td>Bio-Rad</td><td>1610732</td><td>1 L</td></tr><tr><td>Trizma Base</td><td>Sigma-Aldrich</td><td>T1503</td><td>1 kg</td></tr><tr><td>Tryptone, pancreatic</td><td>EMD</td><td>1.07213.1000</td><td>1 kg</td></tr><tr><td>Yeast extract, granulated</td><td>EMD</td><td>1.03753.0500</td><td>500 g</td></tr><tr><td>&amp;nbsp;&amp;Auml;KTApurifier10</td><td>GE Healthcare</td><td>28-4062-64</td><td>Includes kits and accessories</td></tr><tr><td>Benchtop Orbital Shaker</td><td>Thermo Scientific</td><td>SHKE4000</td><td>MAXQ 4000</td></tr><tr><td>BirA500</td><td>Avidity</td><td>BirA500</td><td>Enzyme comes with reaction buffers and biotin solution</td></tr><tr><td>Dialysis Casette</td><td>Thermo Scientific</td><td>66380</td><td>Slide-A-Lyzer (Extra Strength)</td></tr><tr><td>Dialysis Tubing</td><td>Spectrum Laboratories</td><td>132127, 132129</td><td>MWCO: 25,000 and 50,000</td></tr><tr><td>Flow Diversion Valve FV-923</td><td>GE Healthcare</td><td>11-0011-70</td><td></td></tr><tr><td>FluoReporter Biotin Quantification Assay Kit</td><td>Invitrogen</td><td>1094598</td><td></td></tr><tr><td>Frac-950 Tube Racks, Rack C</td><td>GE Healthcare</td><td>18-6083-13</td><td></td></tr><tr><td>Fraction Collector Frac-950</td><td>GE Healthcare</td><td>18-6083-00</td><td>Includes kits and accessories</td></tr><tr><td>Heated/Refrigerated Circulator&amp;nbsp;</td><td>VWR</td><td>13271-102</td><td>Model 1156D</td></tr><tr><td>Heating Oven FD Series</td><td>Binder</td><td></td><td>Model FD 115</td></tr><tr><td>HiLoad 16/60 Superdex 200 pg</td><td>GE Healthcare</td><td>17-1069-01</td><td>Discontinued--Replacement Product: HiLoad 16/600 Superdex 200 pg</td></tr><tr><td>J-26 XPI Avanti Centrifuge</td><td>Beckman Coulter</td><td>393126</td><td></td></tr><tr><td>JA 25.50 Rotor</td><td>Beckman Coulter</td><td>363055</td><td></td></tr><tr><td>JLA 8.1 Rotor</td><td>Beckman Coulter</td><td>969329</td><td>Includes 1 L polyporpylene bottles</td></tr><tr><td>JS 5.3 Rotor</td><td>Beckman Coulter</td><td>368690</td><td></td></tr><tr><td>Laminar Flow Hood</td><td>Themo Scientific</td><td>1849</td><td>Forma 1800 Series Clean Bench</td></tr><tr><td>Microplate Reader</td><td>TECAN</td><td></td><td>infinite M200</td></tr><tr><td>Mini-PROTEAN Tetra Cell</td><td>Bio-Rad</td><td>165-8004</td><td>4-gel vertical electrophoresis system</td></tr><tr><td>Mini-PROTEAN TGX Precast Gels</td><td>Bio-Rad</td><td>456-9036</td><td>Any kDa, 15-well comb</td></tr><tr><td>Ni-NTA Column</td><td>Bio-Rad</td><td>737-2512</td><td>49 ml&amp;nbsp;volume ECONO-Column</td></tr><tr><td>Plasmid Miniprep Kit</td><td>Omega Bio-Tek</td><td>D6943-01</td><td></td></tr><tr><td>PowerPac HC Power Supply</td><td>Bio-Rad</td><td>164-5052</td><td>250 V, 3 A, 300 W</td></tr><tr><td>Round Bottom Polypropylene Copolymer Tubes</td><td>VWR</td><td>3119-0050</td><td>50 ml&amp;nbsp;tubes for JA 25.50 rotor</td></tr><tr><td>Spin-X UF Concentrators</td><td>Corning</td><td>431488, 431483</td><td>&amp;nbsp;20 and 6 ml; MWCO: 10,000 Da</td></tr><tr><td>Subcloning Service</td><td>GenScript USA Inc.</td><td></td><td>Protein Services</td></tr><tr><td>Ultrasonic Processor&amp;nbsp;</td><td>Cole-Parmer</td><td>18910445A</td><td>Model CV18</td></tr><tr><td>Vortex-Genie 2</td><td>Scientific Industries</td><td>SI-0236</td><td>Model G560</td></tr></tbody></table>

expression, isolation, and purification of soluble and insoluble biotinylated proteins for nerve tissue regeneration

Ingegneria proteica ricombinante ha utilizzato Escherichia coli (E. coli) sistemi di espressione per quasi 4 decenni, e oggi E. coli è ancora dell&#39;organismo ospite più utilizzato. La flessibilità del sistema consente l&#39;aggiunta di frazioni come per esempio un tag biotina (per interazioni streptavidina) e proteine ​​funzionali più grandi come proteina fluorescente verde o ciliegio proteina rosso. Inoltre, l&#39;integrazione di amminoacidi innaturali come chelanti di ioni metallici, gruppi funzionali reattivi univoco, sonde spettroscopiche, e molecole che impartiscono modificazioni post-traduzionali ha permesso una migliore manipolazione delle proprietà proteiche e funzionalità. Di conseguenza questa tecnica crea proteine ​​di fusione personalizzabili che offrono utilità significativa per vari campi di ricerca. Più specificamente, la sequenza proteica biotinylatable è stato incorporato in molte proteine ​​bersaglio a causa della elevata interazione affinità tra biotina con avidina e streptavidina. Questa aggiunta ha aiutato a migliorare la rilevazione e purificazione di proteine ​​nella categoria oltre ad aprire la strada ad applicazioni secondarie, come l&#39;ordinamento delle cellule. Così, molecole di biotina marcata mostrano una crescente influenza e diffusa nei campi bioindustriale e biomedica. Ai fini della nostra ricerca abbiamo ingegnerizzato proteine ​​di fusione biotinilato ricombinanti contenenti il ​​fattore di crescita nervoso (NGF) e semaphorin3A (Sema3A) regioni funzionali. Abbiamo precedentemente riportato come queste proteine ​​di fusione biotinilato, insieme ad altre sequenze proteiche attive, possono essere legati a biomateriali per l&#39;ingegneria tissutale e scopi rigenerativi. Questo protocollo delinea le basi delle proteine ​​ingegneria biotinylatable alla scala milligrammo, utilizzando un T7 lac inducibile vettoriale e E. padroni di espressione coli, a partire da trasformazione di scale-up e di purificazione.

<html> Cloning and Test Expression Quando placcatura viene eseguita correttamente, singole colonie isolate dovrebbero costituire per aumentare le possibilità di spennare clonale trasformati batteri cellule (Figura 2A). Tuttavia, se troppe cellule vengono piastrate, piastre vengono incubate troppo tempo a 37 ° C o trasformazione è discutibile, le colonie possono coprire la piastra di agar o formare grandi aggregati di cellule (figure 2b e <...

Watch this Scientific Journal Video about Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration at JoVE.com

Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Sviluppo di proteine ​​di fusione biotinylatable ha molte potenziali applicazioni in diversi campi di ricerca. Ingegneria proteina ricombinante è una procedura dritto in avanti che è costo-efficace, che fornisce alte rese di proteine ​​personalizzati.

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine ​​per Nerve Tissue Regeneration

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most ...

expression-isolation-purification-soluble-insoluble-biotinylated

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

33.5K Views.  University of Akron.  Sviluppo di proteine ​​di fusione biotinylatable ha molte potenziali applicazioni in diversi campi di ricerca. Ingegneria proteina ricombinante è una procedura dritto in avanti che è costo-efficace, che fornisce alte rese di proteine ​​personalizzati. 

Video: Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells

Rhipicephalus microplus &#8211; the cattle tick &#8211; is the most significant ectoparasite in terms of economic impact on livestock as a vector of several pathogens. Efforts have been dedicated to the cattle tick control to diminish its deleterious effects, with focus on the discovery of vaccine candidates, such as BM86, located on the surface of the tick gut epithelial cells. Current research focuses upon the utilization of cDNA and genomic libraries, to screen for other vaccine candidates. The isolation of tick gut cells constitutes an important advantage in investigating the composition of surface proteins upon the tick gut cells membrane. This paper constitutes a novel and feasible method for the isolation of epithelial cells, from the tick gut contents of semi-engorged R. microplus. This protocol utilizes TCEP and EDTA to release the epithelial cells from the subepithelial support tissues and a discontinuous density centrifugation gradient to separate epithelial cells from other cell types. Cell surface proteins were biotinylated and isolated from the tick gut epithelial cells, using streptavidin-linked magnetic beads allowing for downstream applications in FACS or LC-MS/MS-analysis.

Purification of Biotinylated Cell Surface Proteins from Rhipicephalus microplus Epithelial Gut Cells

A modified density centrifugation gradient-based methodology was utilized to isolate epithelial cells from Rhipicephalus microplus gut tissue. Surface-bound proteins were biotinylated and purified through streptavidin magnetic beads for utilization in downstream applications.

Purificazione delle proteine ​​superficiali delle cellule biotinilate da<em&gt; Rhipicephalus microplus</em&gt; Cellule epiteliali delle ghiandole

Rhipicephalus microplus &#8211; the cattle tick &#8211; is the most significant ectoparasite in terms of economic impact on livestock as a vector of ...

Ricerca

Biochimica

In Vitro Biochemical Assays using Biotin Labels to Study Protein-Nucleic Acid Interactions

Protein-nucleic acid interactions play important roles in biological processes such as transcription, recombination, and RNA metabolism. Experimental methods to study protein-nucleic acid interactions require the use of fluorescent tags, radioactive isotopes, or other labels to detect and analyze specific target molecules. Biotin, a non-radioactive nucleic acid label, is commonly used in electrophoretic mobility shift assays (EMSA) but has not been regularly employed to monitor protein activity during nucleic acid processes. This protocol illustrates the utility of biotin labeling during in vitro enzymatic reactions, demonstrating that this label works well with a range of different biochemical assays. Specifically, in alignment with previous findings using radioisotope 32P-labeled substrates, it is confirmed via biotin-labeled EMSA that MEIOB (a protein specifically involved in the meiotic recombination) is a DNA-binding protein, that MOV10 (an RNA helicase) resolves biotin-labeled RNA duplex structures, and that MEIOB cleaves biotin-labeled single-stranded DNA. This study demonstrates that biotin is capable of substituting 32P in various nucleic acid-related biochemical assays in vitro.&#160;

Presented here are protocols for in vitro biochemical assays using biotin labels that may be widely&#160;applicable for studying protein-nucleic acid interactions.

Analisi biochimiche in Vitro che utilizzano etichette di biotina per studiare le interazioni proteina-nucleica dell'acido

Protein-nucleic acid interactions play important roles in biological processes such as transcription, recombination, and RNA metabolism. Experimental ...

Genetica

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons

Regulated endocytic trafficking is the central mechanism facilitating a variety of neuromodulatory events, by dynamically controlling receptor, ion channel, and transporter cell surface presentation on a minutes time scale.&#160;There is a broad diversity of mechanisms that control endocytic trafficking of individual proteins. Studies investigating the molecular underpinnings of trafficking have primarily relied upon surface biotinylation to quantitatively measure changes in membrane protein surface expression in response to exogenous stimuli and gene manipulation.&#160;However, this approach has been mainly limited to cultured cells, which may not faithfully reflect the physiologically relevant mechanisms at play in adult neurons.&#160;Moreover, cultured cell approaches may underestimate region-specific differences in trafficking mechanisms.&#160;Here, we describe an approach that extends cell surface biotinylation to the acute brain slice preparation.&#160;We demonstrate that this method provides a high-fidelity approach to measure rapid changes in membrane protein surface levels in adult neurons.&#160;This approach is likely to have broad utility in the field of neuronal endocytic trafficking.

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons

Neuronal membrane trafficking dynamically controls plasma membrane protein availability and significantly impacts neurotransmission.&#160;To date, it has been challenging to measure neuronal endocytic trafficking in adult neurons.&#160;Here, we describe a highly effective, quantitative method to measure rapid changes in surface protein expression ex vivo in acute brain slices.

Slice Cervello biotinilazione: An<em&gt; Ex Vivo</em&gt; Approccio alla Misura Regione-specifica proteina Tratta plasma membrana in neuroni adulti

Regulated endocytic trafficking is the central mechanism facilitating a variety of neuromodulatory events, by dynamically controlling receptor, ion ...

Neuroscienze

Real-time Imaging of Axonal Transport of Quantum Dot-labeled BDNF in Primary Neurons

BDNF plays an important role in several facets of neuronal survival, differentiation, and function. Structural and functional deficits in axons are increasingly viewed as an early feature of neurodegenerative diseases, including Alzheimer&#8217;s disease (AD) and Huntington&#8217;s disease (HD). As yet unclear is the mechanism(s) by which axonal injury is induced. We reported the development of a novel technique to produce biologically active, monobiotinylated BDNF (mBtBDNF) that can be used to trace axonal transport of BDNF. Quantum dot-labeled BDNF (QD-BDNF) was produced by conjugating quantum dot 655 to mBtBDNF. A microfluidic device was used to isolate axons from neuron cell bodies. Addition of QD-BDNF to the axonal compartment allowed live imaging of BDNF transport in axons. We demonstrated that QD-BDNF moved essentially exclusively retrogradely, with very few pauses, at a moving velocity of around 1.06 &#956;m/sec. This system can be used to investigate mechanisms of disrupted axonal function in AD or HD, as well as other degenerative disorders.

Axonal transport of BDNF, a neurotrophic factor, is critical for the survival and function of several neuronal populations. Some degenerative disorders are marked by disruption of axonal structure and function. We demonstrated the techniques used to examine live trafficking of QD-BDNF in microfluidic chambers using primary neurons.

In tempo reale Imaging del trasporto assonale di Quantum Dot-etichettato BDNF in neuroni primari

BDNF plays an important role in several facets of neuronal survival, differentiation, and function. Structural and functional deficits in axons are ...

Immunostaining of Biocytin-filled and Processed Sections for Neurochemical Markers

Electrophysiological recordings of cells using the patch clamp technique have allowed for the identification of different neuronal types based on firing patterns. The inclusion of biocytin/neurobiotin in the recording electrode permits post-hoc recovery of morphological details, which are necessary to determine the dendritic arborization and the regions targeted by the axons of the recorded neurons. However, given the presence of morphologically similar neurons with distinct neurochemical identities and functions, immunohistochemical staining for cell-type-specific proteins is essential to definitively identify neurons. To maintain network connectivity, brain sections for physiological recordings are prepared at a thickness of 300 &#181;m or greater. However, this thickness often hinders immunohistological postprocessing due to issues with antibody penetration, necessitating the resectioning of the tissue. Resectioning of slices is a challenging art, often resulting in the loss of tissue and morphology of the cells from which electrophysiological data was obtained, rendering the data unusable. Since recovery of morphology would limit data loss and guide in the selection of neuronal markers, we have adopted a strategy of recovering cell morphology first, followed by secondary immunostaining. We introduce a practical approach to biocytin filling during physiological recordings and subsequent serial immunostaining for the recovery of morphology, followed by the restaining of sections to determine the neurochemical identity. We report that sections that were filled with biocytin, fixed with paraformaldehyde (PFA), stained, and coverslipped can be removed and restained with a second primary antibody days later. This restaining involves the removal of the coverslip, the washing of sections in a buffer solution, and the incubation of primary and secondary antibodies to reveal the neurochemical identity. The method is advantageous for eliminating data loss due to an inability to recover morphology and for narrowing down the neurochemical markers to be tested based on morphology.

This protocol presents a method for the morphological recovery of neurons patched during electrophysiological recordings using biocytin filling and subsequent immunohistochemical postprocessing. We show that thick biocytin-filled sections that were stained and coverslipped can be restained with a second primary antibody days&#160;or months later.

Immunocolorazione delle sezioni biocitina-riempite e trasformati per neurochimici Marcatori

Electrophysiological recordings of cells using the patch clamp technique have allowed for the identification of different neuronal types based on firing ...

Determining Cell-surface Expression and Endocytic Rate of Proteins in Primary Astrocyte Cultures Using Biotinylation

Cell-surface proteins mediate a wide array of functions. In many cases, their activity is regulated by endocytic processes that modulate their levels at the plasma membrane. Here, we present detailed protocols for 2 methods that facilitate the study of such processes, both of which are based on the principle of the biotinylation of cell-surface proteins. The first is designed to allow for the semi-quantitative determination of the relative levels of a particular protein at the cell-surface. In it, the lysine residues of the plasma membrane proteins of cells are first labeled with a biotin moiety. Once the cells are lysed, these proteins may then be specifically precipitated via the use of agarose-immobilized streptavidin by exploiting the natural affinity of the latter for biotin. The proteins isolated in such a manner may then be analyzed via a standard western blotting approach. The second method provides a means of determining the endocytic rate of a particular cell-surface target over a period of time. Cell-surface proteins are first modified with a biotin derivative containing a cleavable disulfide bond. The cells are then shifted back to normal culture conditions, which causes the endocytic uptake of a proportion of biotinylated proteins. Next, the disulfide bonds of non-internalized biotin groups are reduced using the membrane-impermeable reducing agent glutathione. Via this approach, endocytosed proteins may thus be isolated and quantified with a high degree of specificity.

Two biotinylation-based methods, designed for determining the cell-surface expression and endocytic rate of proteins expressed at the plasma membrane, are presented in this report.

Determinazione dell&#39;espressione della superficie cellulare e della velocità endocitica delle proteine ​​nelle colture primarie di astrociti usando la biotinilazione

Cell-surface proteins mediate a wide array of functions. In many cases, their activity is regulated by endocytic processes that modulate their levels at ...

Identifying Cell Surface Markers of Primary Neural Stem and Progenitor Cells by Metabolic Labeling of Sialoglycan

Neural stem and progenitor cells (NSPCs) are the cellular basis for the complex structures and functions of the brain. They are located in specialized niches in vivo and can be isolated and expanded in vitro, serving as an important resource for cell transplantation to repair brain damage. However, NSPCs are heterogeneous and not clearly defined at the molecular level or purified due to a lack of specific cell surface markers. The protocol presented, which has been previously reported, combines a neural-endothelial co-culture system with a metabolic glycan labeling method to identify the surface sialoglycoproteome of primary NSPCs. The NSPC-endothelial co-culture system allows self-renewal and expansion of primary NSPCs in vitro, generating a sufficient number of NSPCs. Sialoglycans in cultured NSPCs are labeled using an unnatural sialic acid metabolic reporter with bioorthogonal functional groups. By comparing the sialoglycoproteome from self-renewing NSPCs expanded in an endothelial co-culture with differentiating neural culture, we identify a list of membrane proteins that are enriched in NSPCs. In detail, the protocol involves: 1) set-up of an NSPC-endothelial co-culture and NSPC differentiating culture; 2) labeling with azidosugar per-O-acetylated N-azidoacetylmannosamine (Ac4ManNAz); and 3) biotin conjugation to modified sialoglycan for imaging after fixation of neural culture or protein extraction from neural culture for mass spectrometry analysis. Then, the NSPC-enriched surface marker candidates are selected by comparative analysis of mass spectrometry data from both the expanded NSPC and differentiated neural cultures. This protocol is highly sensitive for identifying membrane proteins of low abundance in the starting materials, and it can be applied to marker discovery in other systems with appropriate modifications

Presented here is a protocol that combines an in vitro neural-endothelial co-culture system and metabolic incorporation of sialoglycan with bioorthogonal functional groups to expand primary neural stem and progenitor cells and label their surface sialoglycoproteins for imaging or mass-spectrometry analysis of cell surface markers.

Identificazione dei marcatori di superficie cellulare delle cellule staminali primarie e delle cellule progenitrici mediante l'etichettatura metabolica di Sialoglycan

Neural stem and progenitor cells (NSPCs) are the cellular basis for the complex structures and functions of the brain. They are located in specialized ...

Purification of Fibroblasts and Schwann Cells from Sensory and Motor Nerves in Vitro

The principal cells in the peripheral nervous system are the Schwann cells (SCs) and the fibroblasts. Both these cells distinctly express the sensory and motor phenotypes involved in different patterns of neurotrophic factor gene expression and other biological processes, affecting nerve regeneration. The present study has established a protocol to obtain highly purified rat sensory and motor SCs and fibroblasts more rapidly. The ventral root (motor nerve) and the dorsal root (sensory nerve) of neonatal rats (7-days-old) were dissociated and the cells were cultured for 4-5 days, followed by isolation of sensory and motor fibroblasts and SCs by combining differential digestion and differential adherence methods sequentially. The results of immunocytochemistry and flow cytometry analyses showed that the purity of the sensory and motor SCs and fibroblasts were &#62;90%. This protocol can be used to obtain a large number of sensory and motor fibroblasts/SCs more rapidly, contributing to the exploration of sensory and motor nerve regeneration.

Here, we present a method to purify fibroblasts and Schwann cells from sensory and motor nerves in vitro.

Purificazione dei fibroblasti e delle cellule di Schwann dai nervi sensoriali e motori in Vitro

The principal cells in the peripheral nervous system are the Schwann cells (SCs) and the fibroblasts. Both these cells distinctly express the sensory and ...

An Improved Protocol to Purify and Directly Mono-Biotinylate Recombinant BDNF in a Tube for Cellular Trafficking Studies in Neurons

Recombinant BDNF containing an Avi sequence (BDNFAvi) is produced in HEK293 cells and then cost-effectively purified by affinity chromatography. A reproducible protocol was developed to directly&#160;mono-biotinylate BDNFAvi with the enzyme BirA in a tube. In this reaction, mono-biotinylated BDNFAvi retains its biological activity.
Neurotrophins are target-derived growth factors playing a role in neuronal development and maintenance. They require rapid transport mechanisms along the endocytic pathway to allow long-distance signaling between different neuronal compartments. The development of molecular tools to study the trafficking of neurotrophins has enabled the precise tracking of these proteins in the cell using in vivo recording. In this protocol, we developed an optimized and cost-effective procedure for the production of mono-biotinylated BDNF. A recombinant BDNF variant containing a biotinylable avi sequence (BDNFAvi) is produced in HEK293 cells in the microgram range and then purified in an easily scalable procedure using affinity chromatography. The purified BDNF can then be homogeneously mono-biotinylated by a direct in vitro reaction with the enzyme BirA in a tube. The biological activity of the mono-biotinylated BDNF (mbtBDNF) can be conjugated to streptavidin-conjugated to different fluorophores. BDNFAvi and mbtBDNF retain their biological activity demonstrated through the detection of downstream phosphorylated targets using western blot and activation of the transcription factor CREB, respectively. Using streptavidin-quantum dots, we were able to visualize mbtBDNF internalization concomitant with activation of CREB, which was detected with a phospho-CREB specific antibody. In addition, mbtBDNF conjugated to streptavidin-quantum dots was suitable for retrograde transport analysis in cortical neurons grown in microfluidic chambers. Thus, in tube produced mbtBDNF is a reliable tool to study physiological signaling endosome dynamics and trafficking in neurons.

Recombinant BDNF containing an Avi sequence (BDNFAvi) is produced in HEK293 cells in a cost-effective manner and is purified by affinity chromatography. BDNFavi is then directly mono-biotinylated with the enzyme BirA in a tube. BDNFavi and mono-biotinylated BDNFavi retain their biological activity when compared to commercially available BDNF.

Un protocollo migliorato per purificare e direttamente mono-biotinyare recombinante BDNF in un tubo per gli studi sul traffico cellulare nei neuroni

Recombinant BDNF containing an Avi sequence (BDNFAvi) is produced in HEK293 cells and then cost-effectively purified by affinity chromatography. A ...

Cell-surface Biotinylation Assay

A cell can regulate the amount of particular proteins on its cell membrane through endocytosis, following which cell surface proteins are effectively sequestered in the cytoplasm. Once within a cell, these surface proteins can be either destroyed or &#8220;recycled&#8221; back to the membrane. The cell surface biotinylation assay provides researchers with a way to study these phenomena. The technique makes use of a derivative of the small molecule biotin, which can label surface proteins and then be chemically cleaved. However, if the surface protein is endocytosed, the biotin derivative will be protected from cleavage. Thus, by analyzing the uncleaved, endocytosed biotin label, scientists can assess the amounts of internalized surface proteins.In this video, we review the concepts behind the biotinylation assay, delving into the chemical structure of the biotin derivative and the mechanism of its cleavage. This is followed by a generalized protocol of the technique, and finally, a description of how researchers are currently using it to study the dynamics of different cell surface proteins.

Saggio di biotinilazione delle proteine di membrana

A cell can regulate the amount of particular proteins on its cell membrane through endocytosis, following which cell surface proteins are effectively ...

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine per Nerve Tissue Regeneration

Riepilogo

Esplora Altri Video

Capitoli in questo video

Purificazione delle proteine superficiali delle cellule biotinilate da

Analisi biochimiche in Vitro che utilizzano etichette di biotina per studiare le interazioni proteina-nucleica dell'acido

Slice Cervello biotinilazione: An

In tempo reale Imaging del trasporto assonale di Quantum Dot-etichettato BDNF in neuroni primari

Immunocolorazione delle sezioni biocitina-riempite e trasformati per neurochimici Marcatori

Determinazione dell'espressione della superficie cellulare e della velocità endocitica delle proteine nelle colture primarie di astrociti usando la biotinilazione

Identificazione dei marcatori di superficie cellulare delle cellule staminali primarie e delle cellule progenitrici mediante l'etichettatura metabolica di Sialoglycan

Purificazione dei fibroblasti e delle cellule di Schwann dai nervi sensoriali e motori in Vitro

Un protocollo migliorato per purificare e direttamente mono-biotinyare recombinante BDNF in un tubo per gli studi sul traffico cellulare nei neuroni

Saggio di biotinilazione delle proteine di membrana

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine ​​per Nerve Tissue Regeneration

Riepilogo

Esplora Altri Video

Capitoli in questo video

Purificazione delle proteine ​​superficiali delle cellule biotinilate da

Analisi biochimiche in Vitro che utilizzano etichette di biotina per studiare le interazioni proteina-nucleica dell'acido

Slice Cervello biotinilazione: An

In tempo reale Imaging del trasporto assonale di Quantum Dot-etichettato BDNF in neuroni primari

Immunocolorazione delle sezioni biocitina-riempite e trasformati per neurochimici Marcatori

Determinazione dell'espressione della superficie cellulare e della velocità endocitica delle proteine ​​nelle colture primarie di astrociti usando la biotinilazione

Identificazione dei marcatori di superficie cellulare delle cellule staminali primarie e delle cellule progenitrici mediante l'etichettatura metabolica di Sialoglycan

Purificazione dei fibroblasti e delle cellule di Schwann dai nervi sensoriali e motori in Vitro

Un protocollo migliorato per purificare e direttamente mono-biotinyare recombinante BDNF in un tubo per gli studi sul traffico cellulare nei neuroni

Saggio di biotinilazione delle proteine di membrana

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine per Nerve Tissue Regeneration

Purificazione delle proteine superficiali delle cellule biotinilate da

Determinazione dell'espressione della superficie cellulare e della velocità endocitica delle proteine nelle colture primarie di astrociti usando la biotinilazione