This work was supported by a grant from the German Research Foundation (DFG; LU1455/1-1).

1. Ex ovo Culture
<ol>
 <li>Fresh fertilized eggs are laid onto their long side in a forced-draft incubator (BSS160, Ehret, Germany) at 37.5 &deg;C with 60% humidity for incubation. Eggs stored at 12 &deg;C for longer than one week should not be used. </li>
 <li>After incubation for 2.5 days (about stage HH17), take out the eggs and label the top with a pencil to indicate direction for cracking. </li>
 <li>Before cracking, pour about 20 ml sterile distilled water into a clean large Petri dish (diamete...

<ol>
	<li>Momose, T., Tonegawa, A., Takeuchi, J., Ogawa, H., Umesono, K., Yasuda, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+targeting+of+gene+expression+in+chick+embryos+by+microelectroporation.">Efficient targeting of gene expression in chick embryos by microelectroporation.</a> Dev. Growth Differ. 41, 335-344 (1999).</li><li>Luo, J., Ju, M. J., Lin, J., Yan, X., Markus, A., Mix, E., Rolfs, A., Redies, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cadherin-20+expression+by+motor+neurons+is+regulated+by+Sonic+hedgehog+during+spinal+cord+development.">Cadherin-20 expression by motor neurons is regulated by Sonic hedgehog during spinal cord development.</a> NeuroReport. 20, 365-370 (2009).</li><li>Luo, J., Ju, M. J., Redies, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regionalized+cadherin-7+expression+by+radial+glia+is+regulated+by+Shh+and+Pax7+during+chicken+spinal+cord+development.">Regionalized cadherin-7 expression by radial glia is regulated by Shh and Pax7 during chicken spinal cord development.</a> Neuroscience. 142, 1133-1143 (2006).</li><li>Nakamura, H., Katahira, T., Sato, T., Watanabe, Y., Funahashi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gain-+and+loss-of-function+in+chick+embryos+by+electroporation.">Gain- and loss-of-function in chick embryos by electroporation.</a> Mech. Dev. 121, 1137-1143 (2004).</li><li>Dai, F., Yusuf, F., Farjah, G. H., Brand-Saberi, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNAi-induced+targeted+silencing+of+developmental+control+genes+during+chicken+embryogenesis.">RNAi-induced targeted silencing of developmental control genes during chicken embryogenesis.</a> Dev. Biol. 258, 80-90 (2005).</li><li>Rao, M., Baraban, J. H., Rajaii, F., Sockanathan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+comparative+study+of+RNAi+methodologies+by+in+ovo+electroporation+in+the+chick+embryo.">In vivo comparative study of RNAi methodologies by in ovo electroporation in the chick embryo.</a> Dev. Dyn. 231, 592-600 (2004).</li><li>Kos, R., Tucker, R. P., Hall, R., Duong, T. D., Erickson, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+introducing+morpholinos+into+the+chicken+embryo.">Methods for introducing morpholinos into the chicken embryo.</a> Dev. Dyn. 226, 470-477 (2003).</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> J. Morphol. 88, 49-92 (1951).</li><li>Auerbach, R., Kubai, L., Knighton, D., Folkman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+procedure+for+the+long-term+cultivation+of+chicken+embryos.">A simple procedure for the long-term cultivation of chicken embryos.</a> Dev. Biol. 10, 391-394 (1974).</li><li>Luo, J., Treubert-Zimmermann, U., Redies, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cadherins+guide+migrating+Purkinje+cells+to+specific+parasagittal+domains+during+cerebellar+development.">Cadherins guide migrating Purkinje cells to specific parasagittal domains during cerebellar development.</a> Mol. Cell. Neurosci. 25, 138-152 (2004).</li><li>Luo, J., Redies, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+ovo+electroporation+for+gene+transfer+into+older+chicken+embryos.">Ex ovo electroporation for gene transfer into older chicken embryos.</a> Dev. Dyn. 233, 1470-1477 (2005).</li><li>Treubert-Zimmermann, U., Heyers, D., Redies, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+axons+to+specific+fiber+tracts+in+vivo+by+altering+cadherin+expression.">Targeting axons to specific fiber tracts in vivo by altering cadherin expression.</a> J. Neurosci. 22, 7617-7626 (2002).</li></ol>

This protocol provides a guide for gene transfer into older chicken embryos (e.g, into the optic tectum at E6) by ex ovo electroporation. This method extends the use of electroporation to older chicken embryos and can be easily applied to many laboratories for studying gene function in vivo at later stages. Embryos from E4 to at least E7 can be successfully electroporated by this method and the electroporated embryos can be survival until E1511. Besides the brain, this method can be also used...

<table border="1">
<tbody>
 <tr>
 <td>Name</td>
 <td>Company</td>
 <td>Catalog 			Number</td>
 </tr>
 <tr>
 <td>Electroporator</td>
 <td>Nepa Gene, Japan</td>
 <td>CUY21-Edit</td>
 </tr>
 <tr>
 <td>Electrodes</td>
 <td>Nepa Gene, Japan</td>
 <td>CUY661-3x7</td>
 </tr>
 <tr>
 <td>Egg incubator</td>
 <td>Ehret, Germany</td>
 <td>BSS160</td>
 </tr>
 <tr>
 <td>Embryo incubator</td>
 <td>BINDER GmbH, Germany</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Fluorescent microscope</td>
 <td>Keyence, 			Deutschland GmbH</td>
 <td>BZ-8000</td>
 </tr>
 <tr>
 <td>Petri dish</td>
 <td>Greiner Bio-One GmbH, 			Germany</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Microelectrode puller</td>
 <td>World Precision 			Instruments, Germany</td>
 <td>PUL-100 </td>
 </tr>
 </tbody>
</table>

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.

Watch this Scientific Journal Video about Gene Transfer into Older Chicken Embryos by ex ovo Electroporation at JoVE.com

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.

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 ...

gene-transfer-into-older-chicken-embryos-by-ex-ovo-electroporation

Research

JoVE Journal

Biology

14.4K visualizações.  School of Medicine University of Rostock. Um método de transferência de genes em embriões de galinha em fases posteriores de incubação (com mais de Hamburger e Hamilton fase (HH) 22) é descrito. Este método supera as desvantagens dos In ovo aplicado aos embriões de galinha e mais velhos é uma técnica útil para estudar a função e regulação gênica em estádios mais avançados de desenvolvimento.