We would like to acknowledge David O'Brien for his support with data analysis, and all the members of the Canto-Soler lab for their critical discussions. This work was supported by NIH grants EY004859 and EY022631 (MVCS), Core Grant EY1765, and an unrestricted departmental grant from Research to Prevent Blindness, Inc.

Alle in dieser Arbeit beschriebenen Verfahren wurden nach den von der Animal Care und Verwenden Ausschuss empfahl der Johns Hopkins University Richtlinien durchgeführt. 1. Ahead of Time: Herstellung von Instrumenten, Reagenzien und Geschirr <ol><li> Herstellung der Eier: Inkubieren befruchteten White Leghorn Hühnereiern bei 37,5 ° C und 60% relativer Luftfeuchtigkeit für 5 Tage in einem Brutkasten. HINWEIS: Ein Inkubator mit Schaukelkapazität kann hilfreich für die Standardisierung und die Synchronisierung der Embryonalentwicklung, aber Schaukel ist für den Ausgang dieses Protokoll unbedingt erforderlich. </li><li> Plasmidpräparation: <ol><li> Design Plasmidkonstrukt zur Gen-Überexpression oder Herunterregulierung (zum Beispiel durch die Verwendung von RNAi-Technik 1,34) je nach Bedarf. Fügen Sie ein Reporter-Gen (wie EGFP, RFP oder LacZ) in dem Konstrukt, wann immer möglich. HINWEIS: Einige häufig verwendete Promotoren, wie CMV, kann nach der Zeit zum Schweigen gebracht zu werden. Die CAG promotER (Huhn-beta-Aktin-Promotor CMV-Enhancer) ist eine sehr gute Alternative, eine effiziente langfristige Expression des Gens von Interesse 35-37. </li><li> Vorbereitung einer Plasmid-Lösung bei einer Konzentration von 1,5 ug / ul in sterilem PBS. OPTIONAL: Bereiten Plasmid-Lösung vor der Zeit und bewahren Sie sie eingefroren, bis gebrauchsfertig. HINWEIS: Höhere Plasmid-Konzentrationen nicht zu einer signifikanten Steigerung der Effizienz führen, wohingegen mit niedrigeren Plasmid-Konzentrationen senken die Transfektionseffizienz 1. </li></ol></li><li> Elektroden: <ol><li> Für die Anode Verwendung einer dicken Gold gekippt Elektrode (siehe Tabelle spezifischer Materialien / Ausrüstung). Wischen Sie mit 70% Ethanol. HINWEIS: Isolierung des Gold gekippt Elektrode, so dass etwa 0,5 mm ausgesetzt sind, ist es ratsam, um ein Auslaufen des elektrischen Stroms zu minimieren. Informationen für Isoliermaterial kann in Tabelle spezifischer Materialien gefunden werden. </li><li> Machen Sie eine Kathode aus einem 2,5 mm Quadrat box Filament, 4,5 mm breit (in der Regel in der Mikropipette Abzieher verwendet). Mit Hilfe einer Pinzette, lösen Sie die quadratische Box und strecken Filaments in einem langen Streifen. Klicken Sie dann unter Dissektionsmikroskop und mit einem Lineal als Führung, biegen Sie das Filament in eine quadratische U-Form 3 mm lang an der Basis und 2 mm hoch auf einer Seite, mit der anderen Seite die verbleibende Länge des Fadens (Abbildung 1 , C - D). Mit einer Pinzette, tauchen Sie die Elektrode in 96% Ethanol und Flamm zu sterilisieren. Bringen Sie dann eine elektrische Leitung mit einer kleinen Krokodilklemme mit dem längeren Arm der Elektrode. </li></ol></li><li> Elektroporationskammer Setup: <ol><li> Vorbereitung der Elektroporation Kammer durch Schneiden des Deckels einer sterilen 1,5-ml-Mikrozentrifugenröhrchen und Befestigen darauf flachen Seite nach unten auf eine 100 mm Petrischale mit Klebeband (1E). Hinweis: andere Behälter in Form eines gut ähnlicher Größe funktionieren würde; ist jedoch ein Mikrozentrifugenröhrchen Deckel leicht zugänglich und autoklavierbar. Der Brunnenmuss groß genug sein, um ein Küken Auge und Kathodenelektrode Haus, aber nicht so groß sein, daß sie zu einer Verschwendung von Plasmid-Lösung führen. </li></ol></li></ol> 2. Ex ovo Elektroporation Ordnung <ol><li> Vorbereitung des Instruments: <ol><li> Sterilisieren Mikrodissektion Werkzeuge (2 Paar große gebogene Moloney Zange zum Öffnen von Eierschalen und Aushöhlungen Embryonen, 2 Paar Feinspitze gekrümmt Dumont Pinzetten zum Entfernen von RPE, ein Paar Bonn gezahnten Pinzette zur Entfernung von Linse und Glas) durch Eintauchen des Tipps in 96% Ethanol und flammenden. Saubere Dissektion Umfang mit Tüchern in 70% Ethanol getaucht. Warm eine Flasche sterile Calcium-Magnesium-freien Hanks Balanced Salt Solution (CMF-HBSS) in einem 37 ° C Wasserbad. Füllen 100 mm sterile Petrischalen bis zu 3/4 mit warmen CMF-HBSS. </li><li> Zeigen Elektroporationskammer unter einem anderen sauberen Dissektionsmikroskop füllen und mit 120 ul von Plasmid-Lösung. Verbinden Elektroden Elektroporationseinrichtung, so dasssicher maßgeschneiderte Elektrode ist mit dem negativen Pol verbunden und Gold gekippt Elektrode an den positiven Pol. </li></ol></li><li> Embryo-Kollektion: <ol><li> Reinigen Sie die Eier durch Abwischen Muscheln mit Tüchern in 70% Ethanol benetzt. Pflegen sterile Verfahren für den Rest des Protokolls zu vermeiden, tragen Verschmutzung in die Kulturen. Verwenden von großen gekrümmten Moloney Zange ein Loch in der Eierschale vorsichtig öffnen durch leichtes Antippen auf der abgerundeten Spitze von einem Ei (über der Luftkammer) und dann Greifen und Herausziehen Schalenstücke. </li><li> Mit einer anderen Pinzette entfernen, Membranen und sammeln Embryos durch Schöpfen sie aus dem Ei (darauf achten, daß der Embryo schädigen). Legen Sie sie in eine Schüssel mit CMF-HBSS. HINWEIS: Sammeln Sie so viele Embryonen wie nötig, um die gewünschte Anzahl von Netzhaut-Tassen für Elektroporation zu erhalten, wie in 2.4.4 festgelegt </li><li> Entscheidender Schritt: Stufe werden die Embryonen nach Hamburger und Hamilton 38. WICHTIG: Um eine optimale Effizienz Embryonen zu erhaltenmuss im Stadium 27 (2A) zu sein. </li><li> Euthanize die Embryonen durch Enthauptung mit Moloney Pinzette. </li></ol></li><li> Beziehen Retinal Cups: <ol><li> Mit feinen Dumont Pinzetten vorsichtig entkernen die Augen und Transfer zu einem neuen CMF-HBSS Gericht. </li><li> Ausgehend von dem hinteren Teil jedes Auge, in der Nähe des Sehnervenkopfes und unter Verwendung von zwei feinen Dumont Pinzetten, präsentieren eine Spitze jedes Pinzette zwischen der neuronalen Netzhaut und RPE und sorgfältig sezieren die RPE vorsichtig zu sein, um nicht die Nervenschäden Netzhaut (2B). HINWEIS: Der Mangel an Ca 2+ und Mg 2+ in der Lösung wird die RPE Herauslösen aus dem neuronalen Netzhaut leichter. </li></ol></li><li> Elektroporation: <ol><li> Parameter Elektroporator eingestellt bis 5 Rechteckimpulse von 15 Volt, 50 ms Dauer und 950 ms-Intervall zu liefern. Platz U-förmige negative Elektrode im Inneren Elektroporationskammer (Mikrozentrifugendeckel filled mit 120 ul von Plasmid-enthaltenden Lösung). </li><li> Verwendung gekrümmt Dumont Pinzetten Übertragung einer Netzhautbecher an die Elektroporation Kammer (mit einer Schöpfkelle, nicht drücken), und legen Sie sie im Inneren des U-förmigen Elektrode, mit dem hinteren Teil der Netzhaut in Richtung der Unterseite der Elektrode und dem Objektiv nach oben ( 2D). </li><li> Legen Sie die Anode, so dass sie den vorderen Teil des Auges berührt, neben dem Objektiv, und mit Hilfe der Elektroporator die Fußpedal den gewünschten elektrischen Impulsen. </li><li> Übertragen elektroporiert retinalen Bechers an eine neue Petrischale mit CMF-HBSS und wiederholen Elektroporationsverfahren mit jedem der übrigen Netzhautschalen. HINWEIS: Bis zu 6 retinalen Becher können mit dem gleichen Plasmid Lösung ohne signifikante Einbußen der Transfektionseffizienz elektroporiert werden. </li><li> Entfernen Sie die Linse und Glaskörper jeder Elektroporation Netzhautbecher durch Greifen sie mit Bonn Zahnzange und leichtes Ziehen durch ter Öffnung Schüler weitergegeben, während das Auge an Ort und Stelle mit der Rückseite der gekrümmten Dumont Pinzetten halten. </li><li> Fahren Sie mit der Dissoziation und Kultur der Elektroporation Netzhautzellen nach Standardverfahren. HINWEIS: Für eine detaillierte Protokoll auf der Dissoziation und Kultur der Küken Netzhautzellen beziehen sich auf Vergara und Canto-Soler, 2012 Weitere Datei 4 21 In diesem Protokoll werden die Zellen bei geringer Dichte auf Polyornithin beschichteten 6-Well-Platten oder 35 ausgesät. -mm Gerichte (6 x 10 5 Zellen / 35 mm-Durchmesser gut oder Schale). Das verwendete Medium ist Medium 199 mit Penicillin / Glutamin, 10% fötalem Kälberserum (FCS) und Linolsäure-BSA bei 100 &amp; mgr; g / ml. Die Kulturen werden in einem befeuchteten Inkubator bei 37ºC mit 5% CO 2 gehalten. Mit dieser Vorgehensweise 5 - kann 6 x 10 6 Zellen in der Regel pro jeder Stufe 27 elektroporiert Auge erhalten werden. HINWEIS: Im Idealfall sollte nicht mehr als 3 Stunden zwischen Embryo-Entnahmeeinheiten und Zellbeschichtung übergeben, um eine gute Zelle Überleben zu sichernund minimieren Stress. Ein typisches Timing für Beobachtung und weiteren Analyse ist nach 4 Tagen in Kultur, da an dieser Stelle die Zellen guten morphologischen und molekularen Differenzierung erreicht und das Überleben ist immer noch hoch. </li></ol></li></ol>

<ol>
	<li>Vergara, M. N., Gutierrez, C., O'Brien, D. R., Canto-Soler, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+electroporation+of+retinal+cells:+a+novel,+high+efficiency+method+for+functional+studies+in+primary+retinal+cultures.">Ex vivo electroporation of retinal cells: a novel, high efficiency method for functional studies in primary retinal cultures.</a> Exp Eye Res. 109, 40-50 (2013).</li><li>Chalmel, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rod-derived+Cone+Viability+Factor-2+is+a+novel+bifunctional-thioredoxin-like+protein+with+therapeutic+potential.">Rod-derived Cone Viability Factor-2 is a novel bifunctional-thioredoxin-like protein with therapeutic potential.</a> BMC Mol Biol. 8, 74 (2007).</li><li>Goureau, O., Regnier-Ricard, F., Desire, L., Courtois, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+nitric+oxide+in+photoreceptor+survival+in+embryonic+chick+retinal+cell+culture.">Role of nitric oxide in photoreceptor survival in embryonic chick retinal cell culture.</a> J Neurosci Res. 55 (4), 423-431 (1999).</li><li>Hewitt, A. T., Lindsey, J. D., Carbott, D., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoreceptor+survival-promoting+activity+in+interphotoreceptor+matrix+preparations:+characterization+and+partial+purification.">Photoreceptor survival-promoting activity in interphotoreceptor matrix preparations: characterization and partial purification.</a> Exp Eye Res. 50 (1), 79-88 (1990).</li><li>Leveillard, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+and+characterization+of+rod-derived+cone+viability+factor.">Identification and characterization of rod-derived cone viability factor.</a> Nat Genet. 36, 755-759 (2004).</li><li>Lorentz, O., Sahel, J., Mohand-Said, S., Leveillard, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cone+survival:+identification+of+RdCVF.">Cone survival: identification of RdCVF.</a> Adv Exp Med Biol. 572, 315-319 (2006).</li><li>Nakamura, M., Singh, D. P., Kubo, E., Chylack Jr, L. T., Shinohara, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LEDGF:+survival+of+embryonic+chick+retinal+photoreceptor+cells.">LEDGF: survival of embryonic chick retinal photoreceptor cells.</a> Invest Ophthalmol Vis Sci. 41 (5), 1168-1175 (2000).</li><li>Paes-de-Carvalho, R., Maia, G. A., Ferreira, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenosine+regulates+the+survival+of+avian+retinal+neurons+and+photoreceptors+in+culture.">Adenosine regulates the survival of avian retinal neurons and photoreceptors in culture.</a> Neurochem Res. 28 (10), 1583-1590 (2003).</li><li>Stenkamp, D. L., Gregory, J. K., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retinoid+effects+in+purified+cultures+of+chick+embryo+retina+neurons+and+photoreceptors.">Retinoid effects in purified cultures of chick embryo retina neurons and photoreceptors.</a> Invest Ophthalmol Vis Sci. 34 (8), 2425-2436 (1993).</li><li>Fuhrmann, S., Kirsch, M., Hofmann, H. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ciliary+neurotrophic+factor+promotes+chick+photoreceptor+development+in+vitro.">Ciliary neurotrophic factor promotes chick photoreceptor development in vitro.</a> Development. 121 (8), 2695-2706 (1995).</li><li>Toy, J., Norton, J. S., Jibodh, S. R., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+homeobox+genes+on+the+differentiation+of+photoreceptor+and+nonphotoreceptor+neurons.">Effects of homeobox genes on the differentiation of photoreceptor and nonphotoreceptor neurons.</a> Invest Ophthalmol Vis Sci. 43 (11), 3522-3529 (2002).</li><li>Yan, R. T., He, L., Wang, S. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pro-photoreceptor+activity+of+chick+neurogenin1.">Pro-photoreceptor activity of chick neurogenin1.</a> Invest Ophthalmol Vis Sci. 50 (12), 5567-5576 (2009).</li><li>Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+neurite+growth+in+purified+retina+neuronal+cultures:+Effects+of+PNPF,+a+substratum-bound,+neurite-promoting+factor.">Regulation of neurite growth in purified retina neuronal cultures: Effects of PNPF, a substratum-bound, neurite-promoting factor.</a> J Neurosci Res. 8 (2-3), 165-177 (1982).</li><li>Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+of+retinal+cell+differentiation+in+the+chick+embryo.">A model of retinal cell differentiation in the chick embryo.</a> Prog Retin Eye Res. 19 (5), 529-557 (2000).</li><li>Adler, R., Hatlee, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasticity+and+differentiation+of+embryonic+retinal+cells+after+terminal+mitosis.">Plasticity and differentiation of embryonic retinal cells after terminal mitosis.</a> Science. 243 (4889), 391-393 (1989).</li><li>Adler, R., Lindsey, J. D., Elsner, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+cone-like+properties+by+chick+embryo+neural+retina+cells+in+glial-free+monolayer+cultures.">Expression of cone-like properties by chick embryo neural retina cells in glial-free monolayer cultures.</a> J Cell Biol. 99 (3), 1173-1178 (1984).</li><li>Adler, R., Magistretti, P. J., Hyndman, A. G., Shoemaker, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+cytochemical+identification+of+neuronal+and+non-neuronal+cells+in+chick+embryo+retina+cultures.">Purification and cytochemical identification of neuronal and non-neuronal cells in chick embryo retina cultures.</a> Dev Neurosci. 5 (1), 27-39 (1982).</li><li>Belecky-Adams, T., Cook, B., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlations+between+terminal+mitosis+and+differentiated+fate+of+retinal+precursor+cells+in+vivo+and+in+vitro:+analysis+with+the+'window-labeling'+technique.">Correlations between terminal mitosis and differentiated fate of retinal precursor cells in vivo and in vitro: analysis with the 'window-labeling' technique.</a> Dev Biol. 178 (2), 304-315 (1996).</li><li>Hyndman, A. G., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+retina+development+in+vitro.+Effects+of+tissue+extracts+on+cell+survival+and+neuritic+development+in+purified+neuronal+cultures.">Neural retina development in vitro. Effects of tissue extracts on cell survival and neuritic development in purified neuronal cultures.</a> Dev Neurosci. 5 (1), 40-53 (1982).</li><li>Politi, L. E., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+enriched+populations+of+cultured+photoreceptor+cells.">Generation of enriched populations of cultured photoreceptor cells.</a> Invest Ophthalmol Vis Sci. 27 (5), 656-665 (1986).</li><li>Vergara, M. N., Canto-Soler, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rediscovering+the+chick+embryo+as+a+model+to+study+retinal+development.">Rediscovering the chick embryo as a model to study retinal development.</a> Neural Dev. 7, 22 (2012).</li><li>Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+cellular+types+in+the+retina.">Determination of cellular types in the retina.</a> Invest Ophthalmol Vis Sci. 34 (5), 1677-1682 (1993).</li><li>Repka, A., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiation+of+retinal+precursor+cells+born+in+vitro.">Differentiation of retinal precursor cells born in vitro.</a> Dev Biol. 153 (2), 242-249 (1992).</li><li>Morris, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Symmetry+in+a+receptor+mosaic+demonstrated+in+the+chick+from+the+frequencies,+spacing+and+arrangement+of+the+types+of+retinal+receptor.">Symmetry in a receptor mosaic demonstrated in the chick from the frequencies, spacing and arrangement of the types of retinal receptor.</a> J Comp Neurol. 140 (3), 359-398 (1970).</li><li>Li, H., Chan, S. T. H., Tang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+of+rat+brain+cells+by+electroporation.">Transfection of rat brain cells by electroporation.</a> J Neurosci Methods. 75 (1), 29-32 (1997).</li><li>Martinez, C. Y., Hollenbeck, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+of+primary+central+and+peripheral+nervous+system+neurons+by+electroporation.">Transfection of primary central and peripheral nervous system neurons by electroporation.</a> Methods Cell Biol. 71, 339-351 (2003).</li><li>Boatright, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+5'+flanking+regions+of+IRBP+and+arrestin+have+promoter+activity+in+primary+embryonic+chicken+retina+cell+cultures.">The 5' flanking regions of IRBP and arrestin have promoter activity in primary embryonic chicken retina cell cultures.</a> Exp Eye Res. 64 (2), 269-277 (1997).</li><li>Dudek, H., Ghosh, A., Greenberg, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+phosphate+transfection+of+DNA+into+neurons+in+primary+culture.">Calcium phosphate transfection of DNA into neurons in primary culture.</a> Curr Protoc Neurosci. Chapter 3, Unit 3.11 (2001).</li><li>Kumar, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+bZIP+transcription+factor+Nrl+stimulates+rhodopsin+promoter+activity+in+primary+retinal+cell+cultures.">The bZIP transcription factor Nrl stimulates rhodopsin promoter activity in primary retinal cell cultures.</a> J Biol Chem. 271 (47), 29612-29618 (1996).</li><li>Toy, J., Bradford, R. L., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid-mediated+gene+transfection+into+chick+embryo+retinal+cells+in+ovo+and+in+vitro.">Lipid-mediated gene transfection into chick embryo retinal cells in ovo and in vitro.</a> J Neurosci Methods. 104 (1), 1-8 (2000).</li><li>Werner, M., Madreperla, S., Lieberman, P., Adler, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+transfected+genes+by+differentiated,+postmitotic+neurons+and+photoreceptors+in+primary+cell+cultures.">Expression of transfected genes by differentiated, postmitotic neurons and photoreceptors in primary cell cultures.</a> J Neurosci Res. 25 (1), 50-57 (1990).</li><li>Yuan, L., Kawada, M., Havlioglu, N., Tang, H., Wu, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+in+PRPF31+inhibit+pre-mRNA+splicing+of+rhodopsin+gene+and+cause+apoptosis+of+retinal+cells.">Mutations in PRPF31 inhibit pre-mRNA splicing of rhodopsin gene and cause apoptosis of retinal cells.</a> J Neurosci. 25 (3), 748-757 (2005).</li><li>Hughes, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+RCAS+vector+system.">The RCAS vector system.</a> Folia Biol (Praha). 50 (3-4), 107-119 (2004).</li><li>Das, R. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+robust+system+for+RNA+interference+in+the+chicken+using+a+modified+microRNA+operon.">A robust system for RNA interference in the chicken using a modified microRNA operon.</a> Dev Biol. 294 (2), 554-563 (2006).</li><li>Nguyen, A. T., Dow, A. C., Kupiec-Weglinski, J., Busuttil, R. W., Lipshutz, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+gene+promoters+for+liver+expression+by+hydrodynamic+gene+transfer.">Evaluation of gene promoters for liver expression by hydrodynamic gene transfer.</a> J Surg Res. 148 (1), 60-66 (2008).</li><li>Xu, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CMV-beta-actin+promoter+directs+higher+expression+from+an+adeno-associated+viral+vector+in+the+liver+than+the+cytomegalovirus+or+elongation+factor+1+alpha+promoter+and+results+in+therapeutic+levels+of+human+factor+X+in+mice.">CMV-beta-actin promoter directs higher expression from an adeno-associated viral vector in the liver than the cytomegalovirus or elongation factor 1 alpha promoter and results in therapeutic levels of human factor X in mice.</a> Hum Gene Ther. 12 (5), 563-573 (2001).</li><li>You, L. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hybrid+promoter-containing+vector+for+direct+cloning+and+enhanced+expression+of+PCR-amplified+ORFs+in+mammalian+cells.">A hybrid promoter-containing vector for direct cloning and enhanced expression of PCR-amplified ORFs in mammalian cells.</a> Mol Biol Rep. 37 (6), 2757-2765 (2009).</li><li>Hamburger, V., Hamilton, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.">A series of normal stages in the development of the chick embryo.</a> Dev Dyn. 195 (4), 231-272 (1992).</li></ol>

The authors declare that they have no competing financial interests or other conflicts of interest.

Der kritischste Schritt für den Erfolg dieses Protokolls ist die Auswahl des geeigneten Stadium der Embryonen. In früheren Veröffentlichungen wird ein Bereich von Embryonalstadien für diesen Kulturen gegeben, die typischerweise von den Tagen Inkubation oder embryonale Tage (ED) definiert sind; somit ist es in der Regel davon ausgegangen, dass die Verwendung von ED 5 bis ED 6 Embryonen zu vergleichbaren Ergebnissen führen. Wir haben jedoch gefunden, dass auf der Bühne 27 (ED &amp; sub5;), wird die Transfektionseffi...

Dissoziierten Zellkulturen von embryonalen Hühnernetzhaut wurden allgemein verwendet, um verschiedene Aspekte der Photorezeptor Zellbiologie, einschließlich deren Überleben 2-9, Differenzierung 10-12, Neuritenwachstum 13 und mehr zu studieren. Die Vorteile dieses Systems, in den 1980er Jahren von Ruben Adler und Mitarbeiter entwickelt und von seinem und anderen Gruppen 14-20, perfektioniert liegen in den intrinsischen Eigenschaften des Kükens als Tiermodell 21. Die Größe des Hühnerauge, auch bei embryonalen Stadien, bietet große Mengen an Material für Kulturen. Außerdem, wenn Kulturen mit embryonalen Tag (ED) durchgeführt 5 - 6 Retinae, 55 - 80% ihrer Vorläuferzellen zu differenzieren, wie Photorezeptoren, 14,15,18,22,23, und da etwa 86% der Photorezeptoren in diesem Tier sind Kegel 24 sind diese Kulturen besonders geeignet für die Studien, die sich auf dieser Zelltyp. Wir haben vor kurzem developed und dadurch eine einfache Technik, die für hocheffiziente Plasmid Transfektion der Zellen in diesen Kulturen ermöglicht, wodurch die Erweiterung der Nützlichkeit dieses Systems durch Erleichterung genetische Studien missexpression 1. Die Entwicklung dieser Technik ergab sich aus einem Hohlraum in der wissenschaftlichen Literatur von Methoden, die ein akzeptables Niveau der Transfektion bereitstellen würde, um für die Untersuchung der Gen-Funktion in einer Zelle autonom zu ermöglichen. Dies ist zum Teil, weil primären neuronalen Kulturen sind notorisch schwer zu transfizieren 25,26. Einige der am häufigsten verwendeten Techniken, die zuvor für diesen Zweck zur Verfügung enthalten chemische Transfektionsverfahren wie Lipofektion oder Calciumphosphat-vermittelte Transfektion, die in Wirkungsgrade in der Grßenordnung von 3-5% führen und kann beträchtliche Toxizität 27-32 auszuüben. Obwohl die Verwendung von Plasmiden mit einem enzymatischen Reporter-Systems kann das Problem der schlechten Transfektionseffizienz durch Verstärken des Signals zu umgehen, sie nichtdiskriminieren zellspezifische Wirkungen, und ihre Ergebnisse werden auf einer kleinen Zellpopulation, die nicht repräsentativ für die gesamte erweisen. Eine andere weit verbreitete Methode in der Küken, RCAS Virus-Infektion, ist nur auf proliferierende Zellen anwendbar und somit nicht für diese primäre Netzhautkultursystem 33 geeignet ist. Im aktuellen Protokoll embryonalen Hühneraugen werden in Stadium 27 (ED &amp; sub5;), der retinalen Pigmentepithel (RPE) wird entfernt, und das Netzhautbecher in einer Elektroporationsküvette Kammer mit einem Plasmid enthaltenden Lösung gefüllt war enukleiert und Elektroporation mit maßgeschneiderten Elektroden, gefolgt von retinalen Dissoziation und Kultur unter Verwendung von Standardtechniken 21. Nach der Optimierung dieses Verfahrens waren wir, ohne die Überlebensrate und Differenzierungsmerkmale der Lage zu Transfektionseffizienzen erzielen durchweg in der Größenordnung von 22% der Gesamtzahl der Zellen in der Kultur und 25% innerhalb der Photorezeptorpopulation AlleinKulturen 1. Hier bieten wir Ihnen ein detailliertes Protokoll umreißt alle wichtigen Schritte dieses Verfahrens, um den Erfolg und die Reproduzierbarkeit dieser Technik zu gewährleisten.

<table><tbody><tr><td>ECM 830 Electro Square Porator</td><td>BTX/ Harvard Apparatus</td><td>45-0052</td><td></td></tr><tr><td>Genetrode, L-Shaped, 5 mm Gold Tip</td><td>BTX/ Harvard Apparatus</td><td>45-0115 model 512</td><td>Gold tipped electrode used as anode</td></tr><tr><td>Polyimide Tubing</td><td>Vention Medical</td><td>custom made</td><td>Internal Diameter: 0.5 mm/wall thickness: 0.15 - 0.2 mm. Used for insulating gold tiped electrode</td></tr><tr><td>2.5 mm square box filament, 4.5 mm wide</td><td>Sutter Instrument Company</td><td>FB245B</td><td>Used to make cathode electrode</td></tr><tr><td>HBSS, no calcium, no magnesium, no phenol red</td><td>Gibco - Life Technologies</td><td>14175-095</td><td></td></tr><tr><td>Moloney forceps</td><td>Roboz</td><td>RS-8254</td><td>Serrated; Slight Curve; 4.5&quot; Length</td></tr><tr><td>Dumont tweezers 5/45</td><td>Roboz</td><td>RS-5058</td><td>Pattern #5, 45 Degree Angle; .10 X .06mm Tip Size; 109mm Length</td></tr><tr><td>Bonn micro forceps, 1x2 teeth</td><td>Roboz</td><td>RS-5172</td><td>Tying Platform; 1x2 Teeth, 0.12 mm Teeth; 3.75&quot; Length; 0.3 mm Tip Width</td></tr></tbody></table>

efficient gene transfer in chick retinas for primary cell culture studies: an ex-ovo electroporation approach

Die Kegelphotorezeptor-angereicherten Kulturen von embryonalen Hühnernetzhaut abgeleitet sind zu einem unverzichtbaren Werkzeug für Forscher auf der ganzen Welt das Studium der Biologie der Netzhautneuronen, insbesondere Photorezeptoren. Die Anwendungen dieses Systems gehen über die Grundlagenforschung, da sie leicht zu Hochdurchsatztechnologien zur Wirkstoffentwicklung angepasst werden. Jedoch genetische Manipulation von retinalen Photorezeptoren in diesen Kulturen hat sich als sehr schwierig, sie eine erhebliche Einschränkung für die Nützlichkeit des Systems. Wir haben vor kurzem entwickelt und validiert eine ex ovo Plasmid Elektroporationstechnik die die Rate der Transfektion von Retinazellen in diesen Kulturen erhöht durch das Fünffache im Vergleich zu anderen gegenwärtig verfügbaren Protokolle 1. Bei diesem Verfahren embryonalen Hühneraugen an Stufe 27 ausgeschält, die RPE wird entfernt, und das Netzhautbecher wird in einem Plasmid-haltigen Lösung gegeben und elektroporiert Verwendung einfach aufgebaut Kundenhergestellten Elektroden. Die Netzhaut werden dann dissoziiert und kultiviert Verwendung von Standardverfahren. Diese Technik kann durch die Verwendung von Plasmid-driven RNAi-Technologie zu Expressionsstudien sowie zu der Herunterregulierung der Genexpression verwendet werden, zum Beispiel, allgemein erzielen die Transgen-Expression in 25% der Photorezeptorpopulation. Das Videoformat der vorliegenden Veröffentlichung wird diese Technologie leicht zugänglich für Forscher auf dem Gebiet zu machen, so dass die Untersuchung von Gen-Funktion in der primären Netzhautkulturen. Wir haben auch detaillierte Erläuterungen der kritischen Schritte dieses Verfahrens für ein erfolgreiches Ergebnis und Reproduzierbarkeit.

Hier präsentieren wir ein einfaches Protokoll für Plasmidtransfektion in entkernte Küken Netzhautbecher für nachfolgende dissoziierten Zellkultur. Transfektion durch Elektroporation unter Verwendung einfach individuelle Elektroden (- 2 Die Zahlen 1) Nutzen erzielt. Die in diesem Protokoll beschriebenen Parameter optimiert wurden Transfektionseffizienzen zwischen 20 und 27% (mit einem Durchschnitt von 22%) (Figur 3D) Bereich zu erhalten. Bemerken, dass bei den oben genannten Gründen...

Watch this Scientific Journal Video about Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach at JoVE.com

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Embryonale Küken Netzhautzellkulturen stellen wertvolle Werkzeuge für das Studium der Photorezeptorbiologie. Wir haben ein effizientes Gentransfertechnik, die auf ex ovo Elektroporation von Plasmid der Netzhaut vor der Kultur entwickelt. Diese Technik wesentlich erhöht Transfektionseffizienzen über derzeit verfügbaren Protokolle, was die genetische Manipulation möglich für dieses System.

Effizienten Gentransfer in Küken Netzhäute für primäre Zellkulturstudien: Eine<em&gt; Ex-ovo</em&gt; Elektroporation Ansatz

The cone photoreceptor-enriched cultures derived from embryonic chick retinas have become an indispensable tool for researchers around the world studying ...

efficient-gene-transfer-chick-retinas-for-primary-cell-culture

Universidad de Cartagena UDEC

Research

JoVE Journal

Developmental Biology

Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

8.2K Aufrufe.  The Johns Hopkins University School of Medicine.  Embryonale Küken Netzhautzellkulturen stellen wertvolle Werkzeuge für das Studium der Photorezeptorbiologie. Wir haben ein effizientes Gentransfertechnik, die auf ex ovo Elektroporation von Plasmid der Netzhaut vor der Kultur entwickelt. Diese Technik wesentlich erhöht Transfektionseffizienzen über derzeit verfügbaren Protokolle, was die genetische Manipulation möglich für dieses System. 

Serie: Efficient Gene Transfer in Chick Retinas for Primary Cell Culture Studies: An Ex-ovo Electroporation Approach

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair cells are aligned in one row of inner hair cells and three rows of outer hair cells that extend along the basal to apical axis of the cochlea. The explant culture technique described here provides an efficient method to isolate and maintain cochlear explants from the embryonic mouse inner ear. Also, the morphology and molecular characteristics of sensory hair cells and nonsensory supporting cells within the cochlear explant cultures resemble those observed in vivo and can be studied within its intrinsic cellular environment. The cochlear explants can serve as important experimental tools for the identification and characterization of molecular and genetic pathways that are involved in cellular specification and patterning. Although transgenic mouse models provide an effective approach for gene expression studies, a considerable number of mouse mutants die during embryonic development thereby hindering the analysis and interpretation of developmental phenotypes. The organ of Corti from mutant mice that die before birth can be cultured so that their in vitro development and responses to different factors can be analyzed. Additionally, we describe a technique for electroporating embryonic cochlear explants ex vivo which can be used to downregulate or overexpress specific gene(s) and analyze their potential endogenous function and test whether specific gene product is necessary or sufficient in a given context to influence mammalian cochlear development1-8.

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear. We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

Kultur von embryonalen Maus Cochlear Explantate und Gentransfer durch Elektroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair ...

Forschung

Entwicklungsbiologie

Whole Retinal Explants from Chicken Embryos for Electroporation and Chemical Reagent Treatments

The retina is a good model for the developing central nervous system. The large size of the eye and most importantly the accessibility for experimental manipulations in ovo/in vivo makes the chicken embryonic retina a versatile and very efficient experimental model. Although the chicken retina is easy to target in ovo by intraocular injections or electroporation, the effective and exact concentration of the reagents within the retina may be difficult to fully control. This may be due to variations of the exact injection site, leakage from the eye or uneven diffusion of the substances. Furthermore, the frequency of malformations and mortality after invasive manipulations such as electroporation is rather high.
This protocol describes an ex ovo technique for culturing whole retinal explants from chicken embryos and provides a method for controlled exposure of the retina to reagents. The protocol describes how to dissect, experimentally manipulate, and culture whole retinal explants from chicken embryos. The explants can be cultured for approximately 24 hr and be subjected to different manipulations such as electroporation. The major advantages are that the experiment is not dependent on the survival of the embryo and that the concentration of the introduced reagent can be varied and controlled in order to determine and optimize the effective concentration. Furthermore, the technique is rapid, cheap and together with its high experimental success rate, it ensures reproducible results. It should be emphasized that it serves as an excellent complement to experiments performed in ovo.

This protocol describes a method to dissect, experimentally manipulate and culture whole retinal explants from chicken embryos. The explant cultures are useful when high success rate, efficacy and reproducibility are needed to test the effects of plasmids for electroporation and/or reagent substances, i.e., enzymatic inhibitors.

Whole Retinal Explantaten aus Hühnerembryonen für die Elektroporation und Reagens-Behandlungen

The retina is a good model for the developing central nervous system. The large size of the eye and most importantly the accessibility for experimental ...

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural connectivity form during development. In mice, retinofugal projections are arranged in a topographic manner and form eye-specific layers in the Lateral Geniculate Nucleus (dLGN) of the thalamus and the Superior Colliculus (SC). The development of these precise patterns of retinofugal projections has typically been studied by labeling populations of RGCs with fluorescent dyes and tracers, such as horseradish peroxidase1-4. However, these methods are too coarse to provide insight into developmental changes in individual RGC axonal arbor morphology that are the basis of retinotopic map formation. They also do not allow for the genetic manipulation of RGCs.
Recently, electroporation has become an effective method for providing precise spatial and temporal control for delivery of charged molecules into the retina5-11. Current retinal electroporation protocols do not allow for genetic manipulation and tracing of retinofugal projections of a single or small cluster of RGCs in postnatal mice. It has been argued that postnatal in vivo electroporation is not a viable method for transfecting RGCs since the labeling efficiency is extremely low and hence requires targeting at embryonic ages when RGC progenitors are undergoing differentiation and proliferation6. 
In this video we describe an in vivo electroporation protocol for targeted delivery of genes, shRNA, and fluorescent dextrans to murine RGCs postnatally. This technique provides a cost effective, fast and relatively easy platform for efficient screening of candidate genes involved in several aspects of neural development including axon retraction, branching, lamination, regeneration and synapse formation at various stages of circuit development. In summary we describe here a valuable tool which will provide further insights into the molecular mechanisms underlying sensory map development.

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

We demonstrate an in vivo electroporation protocol for transfecting single or small clusters of retinal ganglion cells (RGCs) and other retinal cell types in postnatal mice over a wide range of ages. The ability to label and genetically manipulate postnatal RGCs in vivo is a powerful tool for developmental studies.

Die Transfektion von Maus retinalen Ganglienzellen durch In vivo Elektroporation

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural ...

Neurowissenschaften

In vivo Electroporation of Developing Mouse Retina

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge. Gene targeting to generate constitutive or conditional loss of function knockouts remains cost and labor intensive, as well as time consuming. Adding to these challenges, retina expressed genes may have essential roles outside the retina leading to unintended confounds when using a knockout approach. Furthermore, the ability to ectopically express a gene in a gain of function experiment can be extremely valuable when attempting to identify a role in cell fate specification and/or terminal differentiation.
We present a method for the rapid and efficient incorporation of DNA plasmids into the neonatal mouse retina by electroporation. The application of short electrical impulses above a certain field strength results in a transient increase in plasma membrane permeability, facilitating the transfer of material across the membrane 1,2,3,4. Groundbreaking work demonstrated that electroporation could be utilized as a method of gene transfer into mammalian cells by inducing the formation of hydrophilic plasma membrane pores allowing the passage of highly charged DNA through the lipid bilayer 5. Continuous technical development has resulted in the viability of electroporation as a method for in vivo gene transfer in multiple mouse tissues including the retina, the method for which is described herein 6, 7, 8, 9, 10. 
DNA solution is injected into the subretinal space so that DNA is placed between the retinal pigmented epithelium and retina of the neonatal (P0) mouse and electrical pulses are applied using a tweezer electrode. The lateral placement of the eyes in the mouse allows for the easy orientation of the tweezer electrode to the necessary negative pole-DNA-retina-positive pole alignment. Extensive incorporation and expression of transferred genes can be identified by postnatal day 2 (P2). Due to the lack of significant lateral migration of cells in the retina, electroporated and non-electroporated regions are generated. Non-electroporated regions may serve as internal histological controls where appropriate. 
Retinal electroporation can be used to express a gene under a ubiquitous promoter, such as CAG, or to disrupt gene function using shRNA constructs or Cre-recombinase. More targeted expression can be achieved by designing constructs with cell specific gene promoters. Visualization of electroporated cells is achieved using bicistronic constructs expressing GFP or by co-electroporating a GFP expression construct. Furthermore, multiple constructs may be electroporated for the study of combinatorial gene effects or simultaneous gain and loss of function of different genes. Retinal electroporation may also be utilized for the analysis of genomic cis-regulatory elements by generating appropriate expression constructs and deletion mutants. Such experiments can be used to identify cis-regulatory regions sufficient or required for cell specific gene expression 11. Potential experiments are limited only by construct availability.

In vivo Electroporation of Developing Mouse Retina

A method for the incorporation of plasmid DNA into murine retinal cells for the purpose of performing either gain- or loss of function studies in vivo is presented. This method capitalizes on the transient increase in permeability of cell plasma membranes induced by the application of an external electrical field.

In-vivo-Elektroporation von Entwicklung Maus Retina

The functional characterization of genes expressed during mammalian retinal development remains a significant challenge.  Gene targeting to generate ...

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain dopaminergic neurons is implicated in Parkinson's disease, Schizophrenia, depression, and dementia1-5. Thus, studying the regulation of midbrain dopaminergic neuron differentiation could not only provide important insight into mechanisms regulating midbrain development and neural progenitor fate specification, but also help develop new therapeutic strategies for treating a variety of human neurological disorders.
Dopaminergic neurons differentiate from neural progenitors lining the ventricular zone of embryonic ventral midbrain. The development of neural progenitors is controlled by gene expression programs6,7. Here we report techniques utilizing electroporation to express genes specifically in the midbrain of Hamburger Hamilton (HH) stage 11 (thirteen somites, 42 hours) chick embryos8,9. The external development of chick embryos allows for convenient experimental manipulations at specific embryonic stages, with the effects determined at later developmental time points10-13. Chick embryonic neural tubes earlier than HH stage 13 (nineteen somites, 48 hours) consist of multipotent neural progenitors that are capable of differentiating into distinct cell types of the nervous system. The pCAG vector, which contains both a CMV promoter and a chick &beta;-actin enhancer, allows for robust expression of Flag or other epitope-tagged constructs in embryonic chick neural tubes14. In this report, we emphasize special measures to achieve regionally restricted gene expression in embryonic midbrain dopaminergic neuron progenitors, including how to inject DNA constructs specifically into the embryonic midbrain region and how to pinpoint electroporation with small custom-made electrodes. Analyzing chick midbrain at later stages provides an excellent in vivo system for plasmid vector-mediated gain-of-function and loss-of-function studies of midbrain development. Modification of the experimental system may extend the assay to other parts of the nervous system for performing fate mapping analysis and for investigating the regulation of gene expression.

In ovo Electroporation in Chick Midbrain for Studying Gene Function in Dopaminergic Neuron Development

To assess the function and the regulation of genes during the development of midbrain dopaminergic neurons, we describe a method that involves in ovo electroporation of plasmid DNA constructs into embryonic chick ventral midbrain dopaminergic neuron progenitors. This technique can be used to achieve efficient expression of genes of interest to study different aspects of midbrain development and dopaminergic neuron differentiation.

In ovo Elektroporation in Mittelhirn-Küken für Studien über Genfunktion in dopaminergen Neuronen Entwicklung

Dopaminergic neurons located in the ventral midbrain control movement, emotional behavior, and reward mechanisms1-3. The dysfunction of ventral midbrain ...

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell differentiation, axon guidance, retinotopic organization and synapse formation[1]. One drawback is the inability to efficiently and reliably manipulate gene expression in RGCs in vivo, especially in the otherwise accessible murine visual pathways. Transgenic mice can be used to manipulate gene expression, but this approach is often expensive, time consuming, and can produce unwanted side effects. In chick, in ovo electroporation is used to manipulate gene expression in RGCs for examining retina and RGC development. Although similar electroporation techniques have been developed in neonatal mouse pups[2], adult rats[3], and embryonic murine retinae in vitro[4], none of these strategies allow full characterization of RGC development and axon projections in vivo. To this end, we have developed two applications of electroporation, one in utero and the other ex vivo, to specifically target embryonic murine RGCs[5, 6]. 
With in utero retinal electroporation, we can misexpress or downregulate specific genes in RGCs and follow their axon projections through the visual pathways in vivo, allowing examination of guidance decisions at intermediate targets, such as the optic chiasm, or at target regions, such as the lateral geniculate nucleus. Perturbing gene expression in a subset of RGCs in an otherwise wild-type background facilitates an understanding of gene function throughout the retinal pathway. Additionally, we have developed a companion technique for analyzing RGC axon growth in vitro. We electroporate embryonic heads ex vivo, collect and incubate the whole retina, then prepare explants from these retinae several days later. Retinal explants can be used in a variety of in vitro assays in order to examine the response of electroporated RGC axons to guidance cues or other factors. In sum, this set of techniques enhances our ability to misexpress or downregulate genes in RGCs and should greatly aid studies examining RGC development and axon projections.

In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

Here we present two techniques for manipulating gene expression in murine retinal ganglion cells (RGCs) by in utero and ex vivo electroporation. These techniques enable one to examine how alterations in gene expression affect RGC development, axon guidance, and functional properties.

In utero und ex vivo Elektroporation für die Genexpression in Maus retinalen Ganglienzellen

The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell ...

Biologie

Visualization of Tangential Cell Migration in the Developing Chick Optic Tectum

Time-lapse imaging is a powerful method to analyze migrating cell behavior. After fluorescent cell labeling, the movement of the labeled cells in culture can be recorded under video microscopy. For analyzing cell migration in the developing brain, slice culture is commonly used to observe cell migration parallel to the slice section, such as radial cell migration. However, limited information can be obtained from the slice culture method to analyze cell migration perpendicular to the slice section, such as tangential cell migration. Here, we present the protocols for time-lapse imaging to visualize tangential cell migration in the developing chick optic tectum. A combination of cell labeling by electroporation in ovo and a subsequent flat-mount culture on the cell culture insert enables detection of migrating cell movement in the horizontal plane. Moreover, our method facilitates detection of both individual cell behavior and the collective action of a group of cells in the long term. This method can potentially be applied to detect the sequential change of the fluorescent-labeled micro-structure, including the axonal elongation in the neural tissue or cell displacement in the non-neural tissue.

We describe the methods for fluorescent labeling of tangentially migrating cells by electroporation, and for time-lapse imaging of the labeled cell movement in a flat-mount culture in order to visualize migrating cell behavior in the developing chick optic tectum.

Visualisierung der tangentialen Zellwanderung in den Entwicklungsländern Küken Optic Tectum

Time-lapse imaging is a powerful method to analyze migrating cell behavior. After fluorescent cell labeling, the movement of the labeled cells in culture ...

Single Cell Transfection in Chick Embryos

A central theme in developmental biology is the diversification of lineages and the elucidation of underlying molecular mechanisms. This entails a thorough analysis of the fates of single cells under normal and experimental conditions. To this end, transfection methods that target single progenitors are a prerequisite. We describe here a technically straightforward method for transfecting single cells in chicken tissues in-ovo, allowing reliable lineage tracing as well as genetic manipulation. Specific tissue domains are targeted within the somite or neural tube, and DNA is injected directly into the epithelium of interest, resulting in sporadic transfection of single cells. Using reporters, clonal populations may consequently be traced for up to three days, and behavior of genetically manipulated clonal populations can be compared with that of controls. This method takes advantage of the accessibility of the chick embryo along with emerging tools for genetic manipulation. We compare and discuss its advantages over the widely-used electroporation method, and possible applications and use in additional in-vivo models are also suggested. We advocate the use of this method as a significant addition and complement for existing lineage tracing and genetic interference tools.

Using fine tip micropipettes we inject plasmid DNA into subdomains of chicken somites or neural tubes. The concentration of the plasmid is adjusted to generate single transfected cells. We then allow the cells to develop into clonal populations.

Single Cell Transfektion in Hühnerembryonen

A central theme in developmental biology is the diversification of lineages and the elucidation of underlying molecular mechanisms. This entails a ...

In Ovo Electroporation in Embryonic Chick Retina

Chicken embryonic retina is an excellent tool to study retinal development in higher vertebrates. Because of large size and external development, it is comparatively very easy to manipulate the chick embryonic retina using recombinant DNA/RNA technology. Electroporation of DNA/RNA constructs into the embryonic retina have a great advantage to study gene regulation in retinal stem/progenitor cells during retinal development. Different type of assays such as reporter gene assay, gene over-expression, gene knock down (shRNA) etc. can be performed using the electroporation technique. This video demonstrates targeted retinal injection and in ovo electroporation into the embryonic chick retina at the Hamburger and Hamilton stage 22-23, which is about embryonic day 4 (E4). Here we show a rapid and convenient in ovo electroporation technique whereby a plasmid DNA that expresses green fluorescent protein (GFP) as a marker is directly delivered into the chick embryonic subretinal space and followed by electric pulses to facilitate DNA uptake by retinal stem/progenitor cells. The new method of retinal injection and electroporation at E4 allows the visualization of all retinal cell types, including the late-born neurons1, which has been difficult with the conventional method of injection and electroporation at E1.52.

In Ovo Electroporation in Embryonic Chick Retina

The overall goal of this video is to show how to perform targeted retinal injection and in ovo electroporation of DNA/RNA constructs into the chick embryonic retina at the Hamburger and Hamilton stage 22-23, which is about embryonic day 4 (E4). This technique is very useful to study gene expression, gene regulation, and morphological change in developing chick retina.

In ovo Elektroporation in embryonalen Hühnchenretina

Chicken embryonic retina is an excellent tool to study retinal development in higher vertebrates. Because of large size and external development, it is ...

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

The chicken embryo provides an excellent model system for studying gene function and regulation during embryonic development. In ovo electroporation is a powerful method to over-express exogenous genes or down-regulate endogenous genes in vivo in chicken embryos1. Different structures such as DNA plasmids encoding genes2-4, small interfering RNA (siRNA) plasmids5, small synthetic RNA oligos6, and morpholino antisense oligonucleotides7 can be easily transfected into chicken embryos by electroporation. However, the application of in ovo electroporation is limited to embryos at early incubation stages (younger than stage HH20 - according to Hamburg and Hamilton)8 and there are some disadvantages for its application in embryos at later stages (older than stage HH22 - approximately 3.5 days of development). For example, the vitelline membrane at later stages is usually stuck to the shall membrane and opening a window in the shell causes rupture of the vessels, resulting in death of the embryos; older embryos are covered by vitelline and allantoic vessels, where it is difficult to access and manipulate the embryos; older embryos move vigorously and is difficult to control the orientation through a relatively small window in the shell.
In this protocol we demonstrate an ex ovo electroporation method for gene transfer into chicken embryos at late stages (older than stage HH22). For ex ovo electroporation, embryos are cultured in Petri dishes9 and the vitelline and allantoic vessels are widely spread. Under these conditions, the older chicken embryos are easily accessed and manipulated. Therefore, this method overcomes the disadvantages of in ovo electroporation applied to the older chicken embryos. Using this method, plasmids can be easily transfected into different parts of the older chicken embryos10-12.

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

A method of gene transfer into chicken embryos at later incubation stages (older than Hamburger and Hamilton stage (HH) 22) is described. This method overcomes disadvantages of in ovo electroporation applied to older chicken embryos and is a useful technique to study gene function and regulation at older developmental stages.

Gentransfer in Hühnerembryonen durch Ältere<em&gt; Ex ovo</em&gt; Die Elektroporation

The chicken embryo provides an  excellent model system for studying gene function and regulation during  embryonic development. In ovo electroporation is ...

Effizienten Gentransfer in Küken Netzhäute für primäre Zellkulturstudien: Eine

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