The authors thank Leif Oxburgh and Derek Adams for generously sharing their knowledge, Leif Oxburgh for the helpful comments on the manuscript, and Stefan W&#246;lfl and Ulrike M&#252;ller for their technical support and Saskia Schmitteckert , Julia Gobbert, Sascha Weyer and Viola Mayer for help in the lab. This work was supported by Development, The Company of Biologists(to CP).

Mice were maintained according to Swedish regulations and European Union legislation (2010/63/EU). All procedures were performed following the guidelines of the Swedish Ethics Committee (permits C79/9, C248/11, and C135/14). Procedures at Heidelberg University involving animal subjects have been approved by the Regierungspr&#228;sidium Karlsruhe and the Animal Welfare Officers at the University of Heidelberg.
1. Preparation of Reagents and Materials for Culture
NOTE : Use a laminar flow hood to minimize contamination.
<ol>
	<li>On the day of dissection, pre-cluster human Fc alone or recombinant chimeric ephrin protein fused to human Fc by mixing it with anti-human Fc goat antibodies at a molar ratio of 1:5 in sterile phosphate-buffered saline (PBS). Incubate for 1 h at 37 &#176;C5.</li>
	<li>Prepare the culture medium by supplementing Dulbecco&#39;s Modified Eagle Medium: Nutrient Mixture F-12 (DMEM/F12) with 1% penicillin/streptomycin (v/v), 1% glutamine (v/v), 1% insulin-transferrin-selenium (v/v), 50 &#181;g/mL human holo-transferrin, and 1.5 &#181;g/mL amphotericin. 
	NOTE: 10 mL of medium is sufficient for 16 embryos.</li>
	<li>Add clustered recombinant ephrin solution at a final concentration of 20 &#181;g/mL to the culture medium. Use clustered human Fc as control.</li>
	<li>Prepare culture plates by adding 500 &#181;L of culture medium to each well of a sterile, uncoated, flat-bottom polystyrene 4-well plate.</li>
	<li>Using sterile forceps, carefully place one polycarbonate membrane filter with a pore size of 5 &#181;m per well on top of the medium. Transfer the prepared plate to the incubator (37 &#176;C/5% CO2). Ensure that the filter stays dry on the upper surface and floats. 
	NOTE: One filter is sufficient for two kidney anlagen.</li>
	<li>Using a razor blade, cut approximately 30 pipette tips (volume: 100 &#181;L) approximately 1 mm from the tip to result in a wider opening. Place the tips back into a pipette-tip rack.</li>
</ol>
2. Dissection of Metanephric Rudiments at E11.5
<ol>
	<li>Sacrifice a timed-pregnant mouse at E11.5 by cervical dislocation (or using a method approved by the local ethics committee).</li>
	<li>Remove the uterus and the embryos, as described by Brown et al 6. From this point forward, work under a dissection microscope.</li>
	<li>Using No. 5 watchmaker forceps, cut the embryo directly under the forelegs. Use a fresh petri dishfor each embryo. Remove the legs and the tail of the embryo. To do this, grab the tissue to be removed with one pair of No. 5 watchmaker forceps and use the tips of a second pair to cut.</li>
	<li>To remove the ventral organ mass, use the tips of a pair of forceps to laterally open the body wall of the embryo in a rostral-to-caudal direction.
	<ol>
		<li>Cut superficially, parallel to the dorsal aorta. Use the blood-filled and therefore visible dorsal aorta for orientation. Carefully separate the ventral part of the body wall from the dorsal part using the tips of closed forceps and flip the embryo over. Cut the body wall laterally in a rostral-to-caudal direction and using the dorsal aorta for orientation, as for the previous side.</li>
	</ol>
	</li>
	<li>Once the ventral body wall has been separated from the dorsal body, grab it with one pair of forceps and carefully pull to remove it, together with the organ mass. 
	NOTE: The metanephric anlagen usually stay attached to the dorsal body wall. They are oval, ~ 200 &#181;m long structures located at the level of the hind limbs.</li>
	<li>Hold the dorsal body wall with one pair of forceps, with the ventral side facing up. Using the other pair of forceps, grab the dorsal aorta at its rostral end and carefully peel the dorsal aorta from the dorsal body wall. 
	NOTE: Both metanephric kidneys usually stay attached to the dorsal aorta.</li>
	<li>Using one pair of forceps, cut rostrally to the kidney anlagen to remove the aorta. Then, carefully separate the two kidney anlagen using the tips of the forceps.</li>
	<li>Carefully peel off unwanted tissue from the kidney anlagen using the tips of the forceps. Take care not to damage the mesenchyme, as damage can result in poor growth and exclusion of the explant from further analysis.</li>
	<li>Transfer the kidney anlagen separately using a microliter pipette and a wide-open pipette tip in 10 &#181;L of PBS to the polycarbonate membrane filter in a 4-well-plate. 
	NOTE: Due to surface tension, the explant will be covered with a thin layer of medium. One filter is sufficient for two kidney anlagen.
	<ol>
		<li>Place each of the two kidney anlagen at the center of each respective half of the filter. Transfer the plate back to the incubator at 37 &#176;C/5% CO2. Leave the plate in the incubator until the metanephric rudiments from the next embryo are ready to be placed on the filter.</li>
	</ol>
	</li>
	<li>Repeat steps 2.3-2.9.1 for each embryo. 
	NOTE: With some practice, the dissection procedure will take about 5 min per embryo.</li>
	<li>Incubate the kidney anlagen for 3 days at 37 &#176;C/5% CO2.</li>
</ol>
3. Preparation of Reagents for Fixation and Staining
<ol>
	<li>To prepare 4% paraformaldehyde (PFA) in PBS without calcium and magnesium (w/v), dissolve the PFA at 60 &#176;C in PBS, continuously stirring. Cool to room temperature and use a paper filter to remove the remaining particles. Aliquot and keep at 4 &#176;C for immediate use or freeze for long-term storage. 
	CAUTION: PFA is toxic. Wear the personal protective equipment specified in the local safety standards and work in a fume hood. Discard waste following institutional guidelines and using designated waste containers.</li>
	<li>To prepare permeabilization solution, dilute Triton X-100 in PBS without calcium and magnesium to 0.3% (v/v).</li>
	<li>To prepare blocking solution, add 5% (v/v) goat serum and 0.1% Triton X-100 to PBS without calcium and magnesium. Add sodium azide to a final concentration of 0.02% (w/v). Store at 4 &#176;C. 
	CAUTION: Sodium azide is toxic. Handle sodium azide in accordance with the local safety and environmental protection regulations. 
	NOTE: When using antibodies for staining, use 5% serum from the species the secondary antibody was derived from to make blocking solution.</li>
	<li>Dilute biotinylated Dolichorus biflorus agglutinin 1:200 in blocking solution. Dilute Alexa488-conjugated streptavidin 1:200 in blocking solution.</li>
	<li>To make ready-to-use embedding medium (see the table of materials), add 0.1 g of water-soluble polyvinyl alcohol-based mucoadhesive/mL to 25% (w/v) glycerol in 0.1 M Tris-HCl (pH 8.5). Heat to 50 &#176;C under continuous agitation for 1 h, cool down, and adjust the pH to 8.0-8.5 using 1 M NaOH. Avoid higher NaOH concentrations. Add 100 &#181;g/mL N-propylgallate and thimerosal to a final concentration of 0.02% (w/v). Stir for 30 min at room temperature. 
	CAUTION: Thimerosal is toxic. Handle it in accordance with the local safety and environmental protection regulations.
	<ol>
		<li>Fill the embedding medium in 50 mL tubes, balance the rotor, and centrifuge at 3,200 x g and room temperature for 10 min. Decant the clear solution into 15 mL tubes and discard the pellet. Aliquot and store at -20 &#176;C for several weeks. Once thawed, keep the solution at 4 &#176;C. Warm to ~30 &#176;C immediately before use.</li>
	</ol>
	</li>
	<li>Prepare as many glass slides as filters with explants are to be mounted. For this, glue two small coverslips, 18 x 18 mm, on either side of the glass slide using instant adhesive, Leave a ~15 mm space for the filter in between.</li>
</ol>
4. Fixation and staining
<ol>
	<li>After a culturing period of 3 days in vitro (div), remove the plates from the incubator and carefully aspirate the culture medium from each well using a micropipette. Make sure not to touch the filter and keep the tip opening towards the wall of the well.</li>
	<li>Add 500 &#181;L of 4% PFA/PBS to each well. The filters will float on the fixative. Using a micropipette, carefully add the PFA fixative dropwise to submerge the filters. Incubate at room temperature for 30 min. 
	NOTE: For all following steps, care must be taken not to wash off the explants from the filter. Keep the opening of the pipette tip towards the wall of the well.</li>
	<li>Remove the PFA and rinse twice with 500 &#181;L of PBS, submerging the filter. Add 500 &#181;L of permeabilization solution to each well and incubate at room temperature for 1 h.</li>
	<li>Rinse twice with 500 &#181;L of PBS and add 500 &#181;L of blocking solution to each well. Incubate at room temperature for 1 h.</li>
	<li>Replace the blocking solution with 250 &#181;L of biotinylated Dolichorus biflorus agglutinin diluted 1:200 in blocking solution and incubate at 4 &#176;C for 24 h.</li>
	<li>Remove the Dolichorus biflorus agglutinin solution and rinse twice with 500 &#181;L of PBS per well.</li>
	<li>Add 250 &#181;L of Alexa488-conjugated streptavidin diluted 1:200 in blocking solution and incubate at 4 &#176;C for 24 h. Alternatively, incubate at room temperature for 2 h. 
	NOTE: A better signal-to-noise ratio is achieved when incubated at 4 &#176;C.</li>
	<li>Rinse twice with 500 &#181;L of PBS per well. Using forceps, transfer the filters to the prepared glass slides, with the explants facing up. Mount with ~50-100 &#181;L of embedding medium. Cover with 60 mm-long No. 1.5 coverslips. Allow the embedding medium solution to solidify for 2 h at room temperature in the dark. Proceed to imaging or store the slides, wrapped in foil, at 4 &#176;C until ready to image.</li>
	<li>Image with a widefield epifluorescence microscope7 coupled to an Hg-lamp and use a mirror unit for blue excitation (excitation bandpass, 460 - 495 nm; dichromatic mirror, 505 nm; and emission bandpass, 510 - 550 nm) and 20X Plan-Apochromat lenses, 0.75 numerical aperture.</li>
</ol>

<ol>
	<li>Sax&#233;n, 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> Organogenesis of the kidney. Developmental and Cell Biology Series. 19, (1987).</li><li>Lindstr&#246;m, N. O., 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=Integrated+&#946;-catenin,+BMP,+PTEN,+and+Notch+signalling+patterns+the+nephron.">Integrated &#946;-catenin, BMP, PTEN, and Notch signalling patterns the nephron.</a> eLife. 4, e04000 (2015).</li><li>Peuckert, C., 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=Multimodal+Eph/Ephrin+signaling+controls+several+phases+of+urogenital+development.">Multimodal Eph/Ephrin signaling controls several phases of urogenital development.</a> Kidney Int. 90 (2), 373-388 (2016).</li><li>Pasquale, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eph+receptor+signalling+casts+a+wide+net+on+cell+behaviour.">Eph receptor signalling casts a wide net on cell behaviour.</a> Nat Rev Mol Cell Biol. 6 (6), 462-475 (2005).</li><li>Bonanomi, D., 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=Ret+Is+a+Multifunctional+Coreceptor+that+Integrates+Diffusible-+and+Contact-Axon+Guidance+Signals.">Ret Is a Multifunctional Coreceptor that Integrates Diffusible- and Contact-Axon Guidance Signals.</a> Cell. 148 (2), 568-582 (2012).</li><li>Brown, A. C., 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=Isolation+and+Culture+of+Cells+from+the+Nephrogenic+Zone+of+the+Embryonic+Mouse+Kidney.">Isolation and Culture of Cells from the Nephrogenic Zone of the Embryonic Mouse Kidney.</a> J Vis Exp. (50), e2555 (2011).</li><li>Grobstein, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inductive+interaction+in+the+development+of+the+mouse+metanephros.">Inductive interaction in the development of the mouse metanephros.</a> J Exp Zool. 130, 319-340 (1955).</li><li>Sax&#233;n, L., Toivonen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Primary Embryonic Induction. , (1962).</li><li>Sax&#233;n, L., Koskimies, O., Lahti, A., Miettinen, H., Rapola, J., Wartiovaara, J. <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+kidney+mesenchyme+in+an+experimental+model+system.">Differentiation of kidney mesenchyme in an experimental model system.</a> Adv Morphog. 7, 251-293 (1968).</li><li>Dudley, A. T., Godin, R. E., Robertson, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interaction+between+FGF+and+BMP+signaling+pathways+regulates+development+of+metanephric+mesenchyme.">Interaction between FGF and BMP signaling pathways regulates development of metanephric mesenchyme.</a> Genes Dev. 13, 1601-1613 (1999).</li><li>Per&#228;l&#228;, N., 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=Sema4C-Plexin+B2+signalling+modulates+ureteric+branching+in+developing+kidney.">Sema4C-Plexin B2 signalling modulates ureteric branching in developing kidney.</a> Differentiation. 81 (2), 81-91 (2011).</li><li>Thesleff, I., Ekblom, P. <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+transferrin+in+branching+morphogenesis,+growth+and+differentiation+of+the+embryonic+kidney.">Role of transferrin in branching morphogenesis, growth and differentiation of the embryonic kidney.</a> J Embryol exp Morph. 82, 147-161 (1984).</li><li>Watanabe, T., Costantini, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+analysis+of+ureteric+bud+branching+morphogenesis.">Real-time analysis of ureteric bud branching morphogenesis.</a> Dev Biol. 271, 98-108 (2004).</li><li>Sebinger, D. D. R., Unbekandt, M., Ganeva, V. V., Ofenbauer, A., Werner, C., Davies, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel,+Low-Volume+Method+for+Organ+Culture+of+Embryonic+Kidneys+That+Allows+Development+of+Cortico-Medullary+Anatomical+Organization.">A Novel, Low-Volume Method for Organ Culture of Embryonic Kidneys That Allows Development of Cortico-Medullary Anatomical Organization.</a> PLoS One. 5 (5), e10550 (2010).</li><li>Ekblom, P., Miettinen, A., Virtanen, I., Wahlstr&#246;m, T., Dawnay, A., Sax&#233;n, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+segregation+of+the+metanephric+nephron.">In vitro segregation of the metanephric nephron.</a> Dev Biol. 84 (1), 88-95 (1981).</li><li>Davies, J. A., Unbekandt, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=siRNA-mediated+RNA+interference+in+embryonic+kidney+organ+culture.">siRNA-mediated RNA interference in embryonic kidney organ culture.</a> Methods Mol Biol. 886, 295-303 (2012).</li><li>Sax&#233;n, L., Lehtonen, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+kidney+in+organ+culture.">Embryonic kidney in organ culture.</a> Differentiation. 36 (1), 2-11 (1987).</li><li>Bard, J. B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+development+of+the+mouse+kidney+embryogenesis+writ+small.">The development of the mouse kidney embryogenesis writ small.</a> Curr Opin Genet Dev. 2, 589-595 (1992).</li><li>Davies, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+cold+storage+and+transport+of+viable+embryonic+kidney+rudiments.">A method for cold storage and transport of viable embryonic kidney rudiments.</a> Kidney Int. 70 (11), 2031-2034 (2006).</li><li>Batourina, E., 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=Distal+ureter+morphogenesis+depends+on+epithelial+cell+remodeling+mediated+by+vitamin+A+and+Ret.">Distal ureter morphogenesis depends on epithelial cell remodeling mediated by vitamin A and Ret.</a> Nat Genet. 32 (1), 109-115 (2002).</li></ol>

The authors have nothing to disclose.

This manuscript describes a method to isolate the developing metanephric anlagen from the mouse embryo and to culture the organ rudiments. This method is a standard technique, as developed by Grobstein8 and Sax&#233;n9,10, and was adapted and modified by many others11,12. The success of the method depends mainly on the duration of the dissection, as explant survival and inductive p...

The mammalian kidney is derived from two primordial structures with mesodermal origin: the tubular epithelial ureteric bud and the metanephric mesenchyme. During nephrogenesis, the ureteric bud invades the metanephric mesenchyme and branches to form the collecting system. The metanephric mesenchyme gives rise to the epithelial elements of the nephrons. These processes occur in a precisely timed and spatially coordinated manner and are initiated by reciprocal inductive mechanisms. Both tissue components communicate and affect the other's cell morphogenesis. 
In the 1920s, it was Boyden who performed the in vivo obstruction of the mesonephric duct in chicken, providing the first indication of inductive interactions as separated nephric blastema fail to differentiate1. At about the same time, the first successful attempts to culture chicken nephric rudiments in a hanging drop were published. Subsequently, the organ culture was developed to study tissue interactions in mammalian organogenesis. In the 1950s, Grobstein developed a technique in which metanephric rudiments could be cultured on a filter. This technique was modified by Sax&#233;n, who placed the filter on a Trowell-type screen in a culture dish1. Over the years, many modifications and applications for organ culture have emerged. The method described here is based on Sax&#233;n's technique but is simplified, as the filters float free on the medium and the diameter of the culture well only slightly exceeds the diameter of the filter, limiting unwanted movement of the filter.
Whole-organ culture is a classical, cheap, and simple but powerful tool to investigate cellular processes and intercellular communication during organogenesis. Organ culture allows for treatment with biological agents, such as growth factors, antibodies, antisense oligonucleotides, viruses, and peptides, as well as with pharmaceutical compounds and other chemicals. Also, gene function may be studied using explants derived from genetically modified mice or using inducible gene inactivation technology, such as the Cre-loxP system. This allows for the study of genetic mutations that cause embryonic lethality prior to the development of the kidney. Organ culture can also be combined with fluorescent tagging for gene function or lineage tracing and modern imaging techniques, which enable real-time monitoring of cell behavior2.
In the specific example provided here, the effect of EphrinB2-activated Eph-receptor signaling on the branching morphology of the ureteric bud was investigated. The morphology of the EphA4/EphB2 double-knockout mice suggested several severe defects in kidney development, which were detectable as early as embryonic day 11 (E11) and involved the ureteric bud, the ureter, and the common nephric duct3. Signaling via Eph receptors requires the clustering of the ligand-receptor dimer4. To over-activate Eph signaling, the kidney rudiments from E11.5 mouse embryos were cultured in the presence of clustered recombinant EphrinB2-Fc. EphrinB2 is a known ligand for the EphA4 receptor, which is expressed in the ureteric bud tips3.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>DMEM/F-12</td>
			<td>Thermo Fisher Scientific</td>
			<td>21331020</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (10,000 U/mL)</td>
			<td>Thermo Fisher Scientific</td>
			<td>15140148</td>
			<td></td>
		</tr>
		<tr>
			<td>GlutaMAX Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>35050061</td>
			<td></td>
		</tr>
		<tr>
			<td>DPBS, calcium, magnesium</td>
			<td>Thermo Fisher Scientific</td>
			<td>14040117</td>
			<td>use for dissection</td>
		</tr>
		<tr>
			<td>holo-Transferrin human</td>
			<td>Sigma-Aldrich</td>
			<td>T0665</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin-Transferrin-Selenium (ITS -G) (100X)</td>
			<td>Thermo Fisher Scientific</td>
			<td>41400045</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>158127</td>
			<td></td>
		</tr>
		<tr>
			<td>Amphotericin B solution</td>
			<td>Sigma-Aldrich</td>
			<td>A2942</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>X100</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium azide</td>
			<td>Sigma-Aldrich</td>
			<td>S8032</td>
			<td></td>
		</tr>
		<tr>
			<td>Thimerosal</td>
			<td>Sigma-Aldrich</td>
			<td>T5125</td>
			<td></td>
		</tr>
		<tr>
			<td>Propyl gallate</td>
			<td>Sigma-Aldrich</td>
			<td>2370</td>
			<td></td>
		</tr>
		<tr>
			<td>Mowiol 4-88</td>
			<td>Sigma-Aldrich</td>
			<td>81381</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma-Aldrich</td>
			<td>G5516</td>
			<td></td>
		</tr>
		<tr>
			<td>Biotinylated Dolichorus Biflorus Agglutinin</td>
			<td>Vector Laboratories</td>
			<td>B-1035</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa488 conjugated Streptavidin</td>
			<td>Jackson Immuno Research</td>
			<td>016-540-084</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Mouse Ephrin-B2 Fc Chimera Protein, CF</td>
			<td>R&#38;D Systems</td>
			<td>496-EB</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Human IgG1 Fc, CF</td>
			<td>R&#38;D Systems</td>
			<td>110-HG-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat Anti-Human IgG Fc Antibody</td>
			<td>R&#38;D Systems</td>
			<td>G-102-C</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline tablets</td>
			<td>Sigma-Aldrich</td>
			<td>P4417</td>
			<td>use for fixation and immunostaining</td>
		</tr>
		<tr>
			<td>Dumont #5, biologie 
			tips, INOX, 11cm</td>
			<td>agnthos.se</td>
			<td>0208-5-PS</td>
			<td>2 pairs of forceps are needed</td>
		</tr>
		<tr>
			<td>Iris scissors, straight, 12cm</td>
			<td>agnthos.se</td>
			<td>03-320-120</td>
			<td></td>
		</tr>
		<tr>
			<td>Dressing Forceps, 
			straight, delicate, 13cm</td>
			<td>agnthos.se</td>
			<td>08-032-130</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dishes Nunclo Delta treated</td>
			<td>Thermo Fisher Scientific</td>
			<td>150679</td>
			<td></td>
		</tr>
		<tr>
			<td>TMTP01300 Isopore Membrane Filter, polycarbonate, Hydrophilic, 5.0 &#181;m, 13 mm, white, plain</td>
			<td>MerckMillipore</td>
			<td>TMTP01300</td>
			<td></td>
		</tr>
		<tr>
			<td>Nunclon Multidishes 
			4 wells, flat bottom</td>
			<td>Sigma-Aldrich</td>
			<td>D6789-1CS</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope cover glass24x50mm thickn. No.1.5H 0.17+/-0.005mm</td>
			<td>nordicbiolabs</td>
			<td>107222</td>
			<td></td>
		</tr>
		<tr>
			<td>Cover glasses No.1.5, 18x18mm</td>
			<td>nordicbiolabs</td>
			<td>102032</td>
			<td></td>
		</tr>
		<tr>
			<td>Slides ~76x26x1, 1/2-w. ground plain</td>
			<td>nordicbiolabs</td>
			<td>1030418</td>
			<td></td>
		</tr>
		<tr>
			<td>VWR Razor Blades</td>
			<td>VWR</td>
			<td>55411-055</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL centrifuge tubes</td>
			<td>Sigma-Aldrich</td>
			<td>CLS430828</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL centrifuge tubes</td>
			<td>Sigma-Aldrich</td>
			<td>CLS430055</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatman prepleated qualitative filter paper, Grade 113V, creped</td>
			<td>Sigma-Aldrich</td>
			<td>WHA1213125</td>
			<td></td>
		</tr>
		<tr>
			<td>Fixed stage research mircoscope</td>
			<td>Olympus</td>
			<td>BX61WI</td>
			<td></td>
		</tr>
		<tr>
			<td>Black 6 inbred mice, male, C57BL/6NTac</td>
			<td>Taconic</td>
			<td>B6-M</td>
			<td></td>
		</tr>
		<tr>
			<td>Black 6 inbred mice,female, C57BL/6NTac</td>
			<td>Taconic</td>
			<td>B6-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Greenough Stereo Microscope</td>
			<td>Leica</td>
			<td>Leica S6 E</td>
			<td></td>
		</tr>
	</tbody>
</table>

dissection and culture of mouse embryonic kidney

The goal of this protocol is to describe a method for the dissection, isolation, and culture of mouse metanephric rudiments. 
During mammalian kidney development, the two progenitor tissues, the ureteric bud and the metanephric mesenchyme, communicate and reciprocally induce cellular mechanisms to eventually form the collecting system and the nephrons of the kidney. As mammalian embryos grow intrauterine and therefore are inaccessible to the observer, an organ culture has been developed. With this method, it is possible to study epithelial-mesenchymal interactions and cellular behavior during kidney organogenesis. Furthermore, the origin of congenital kidney and urogenital tract malformations can be investigated. After careful dissection, the metanephric rudiments are transferred onto a filter that floats on culture medium and can be kept in a cell culture incubator for several days. However, one must be aware that the conditions are artificial and could influence the metabolism in the tissue. Also, the penetration of test substances could be limited due to the extracellular matrix and basal membrane present in the explant.
One main advantage of organ culture is that the experimenter can gain direct access to the organ. This technology is cheap, simple, and allows a large number of modifications, such as the addition of biologically active substances, the study of genetic variants, and the application of advanced imaging techniques.

Metanephric kidney anlagen were derived from pregnant Black-6 inbred mice at E11.5 and were cultured. After 3 days, the ureteric bud had branched up to 5 times, resulting in a ramification of the initially T-shaped ureteric bud. Each explant was photographed, and the numbers of segments and endpoints were quantified to determine the branching generations and to calculate the number of endpoints per branch (Figure 1). ImageJ (rd generation; the 4th ge...

Watch this Scientific Journal Video about Dissection and Culture of Mouse Embryonic Kidney at JoVE.com

Dissection and Culture of Mouse Embryonic Kidney

This protocol describes a method for isolating and culturing metanephric rudiments from mouse embryos.

The goal of this protocol is to describe a method for the dissection, isolation, and culture of mouse metanephric rudiments. 
During mammalian kidney ...

dissection-and-culture-of-mouse-embryonic-kidney

Research

JoVE Journal

Developmental Biology

11.8K Views.  Uppsala University. This protocol describes a method for isolating and culturing metanephric rudiments from mouse embryos.

Video: Dissection and Culture of Mouse Embryonic Kidney

Large-scale Zebrafish Embryonic Heart Dissection for Transcriptional Analysis

The zebrafish embryonic heart is composed of only a few hundred cells, representing only a small fraction of the entire embryo. Therefore, to prevent the cardiac transcriptome from being masked by the global embryonic transcriptome, it is necessary to collect sufficient numbers of hearts for further analyses. Furthermore, as zebrafish cardiac development proceeds rapidly, heart collection and RNA extraction methods need to be quick in order to ensure homogeneity of the samples. Here, we present a rapid manual dissection protocol for collecting functional/beating hearts from zebrafish embryos. This is an essential prerequisite for subsequent cardiac-specific RNA extraction to determine cardiac-specific gene expression levels by transcriptome analyses, such as quantitative real-time polymerase chain reaction (RT-qPCR). The method is based on differential adhesive properties of the zebrafish embryonic heart compared with other tissues; this allows for the rapid physical separation of cardiac from extracardiac tissue by a combination of fluidic shear force disruption, stepwise filtration and manual collection of transgenic fluorescently labeled hearts.

To analyse cardiac gene expression profiles during zebrafish heart development, total RNA has to be extracted from isolated hearts. Here, we present a protocol for collecting functional/beating hearts by rapid manual dissection from zebrafish embryos to obtain cardiac-specific mRNA.

The zebrafish embryonic heart is composed of only a few hundred cells, representing only a small fraction of the entire embryo. Therefore, to prevent the ...

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.

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

Culture and Co-Culture of Mouse Ovaries and Ovarian Follicles

The mammalian ovary is composed of ovarian follicles, each follicle consisting of a single oocyte surrounded by somatic granulosa cells, enclosed together within a basement membrane. A finite pool of follicles is laid down during embryonic development, when oocytes in meiotic arrest form a close association with flattened granulosa cells, forming primordial follicles. By or shortly after birth, mammalian ovaries contain their lifetime&#8217;s supply of primordial follicles, from which point onwards there is a steady release of follicles into the growing follicular pool.
The ovary is particularly amenable to development in vitro, with follicles growing in a highly physiological manner in culture. This work describes the culture of whole neonatal ovaries containing primordial follicles, and the culture of individual ovarian follicles, a method which can support the development of follicles from an immature through to the preovulatory stage, after which their oocytes are able to undergo fertilization in vitro. The work outlined here uses culture systems to determine how the ovary is affected by exposure to external compounds. We also describe a co-culture system, which allows investigation of the interactions that occur between growing follicles and the non-growing pool of primordial follicles.

This protocol describes the primary culture/co-culture of mouse ovarian tissue, using ovaries from neonatal mice and individual ovarian follicles from prepubertal mice. The culture techniques support development in a highly physiological manner, allowing investigation of the effect of extrinsic agents on the ovary, and of interactions between ovarian follicles.

The mammalian ovary is composed of ovarian follicles, each follicle consisting of a single oocyte surrounded by somatic granulosa cells, enclosed together ...

Neural Differentiation of Mouse Embryonic Stem Cells in Serum-free Monolayer Culture

The ability to differentiate mouse embryonic stem cells (ESC) to neural progenitors allows the study of the mechanisms controlling neural specification as well as the generation of mature neural cell types for further study. In this protocol we describe a method for the differentiation of ESC to neural progenitors using serum-free, monolayer culture. The method is scalable, efficient and results in production of ~70% neural progenitor cells within 4 - 6 days. It can be applied to ESC from various strains grown under a variety of conditions. Neural progenitors can be allowed to differentiate further into functional neurons and glia or analyzed by microscopy, flow cytometry or molecular techniques. The differentiation process is amenable to time-lapse microscopy and can be combined with the use of reporter lines to monitor the neural specification process. We provide detailed instructions on media preparation and cell density optimization to allow the process to be applied to most ESC lines and a variety of cell culture vessels.

This protocol describes in detail the method for generating neural progenitors from embryonic stem cells using a serum-free monolayer method. These progenitors can be used to derive mature neural cell types or to study the process of neural specification and is amenable to multiwell format scaling for compound screening.

The ability to differentiate mouse embryonic stem cells (ESC) to neural progenitors allows the study of the mechanisms controlling neural specification as ...

Transcriptome Profiling of In-Vivo Produced Bovine Pre-implantation Embryos Using Two-color Microarray Platform

Early embryonic loss is a large contributor to infertility in cattle. Moreover, bovine becomes an interesting model to study human preimplantation embryo development due to their similar developmental process. Although genetic factors are known to affect early embryonic development, the discovery of such factors has been a serious challenge. Microarray technology allows quantitative measurement and gene expression profiling of transcript levels on a genome-wide basis. One of the main decisions that have to be made when planning a microarray experiment is whether to use a one- or two-color approach. Two-color design increases technical replication, minimizes variability, improves sensitivity and accuracy as well as allows having loop designs, defining the common reference samples. Although microarray is a powerful biological tool, there are potential pitfalls that can attenuate its power. Hence, in this technical paper we demonstrate an optimized protocol for RNA extraction, amplification, labeling, hybridization of the labeled amplified RNA to the array, array scanning and data analysis using the two-color analysis strategy.

Transcriptome Profiling of In-Vivo Produced Bovine Pre-implantation Embryos Using Two-color Microarray Platform

Microarray technology allows quantitative measurement and gene expression profiling of transcripts on a genome-wide basis. Therefore, this protocol provides an optimized technical procedure in a two-color custom made bovine array using Day 7 bovine embryos to demonstrate the feasibility of using low amount of total RNA.

Early embryonic loss is a large contributor to infertility in cattle. Moreover, bovine becomes an interesting model to study human preimplantation embryo ...

Culture of Murine Embryonic Metatarsals: A Physiological Model of Endochondral Ossification

The fundamental process of endochondral ossification is under tight regulation in the healthy individual so as to prevent disturbed development and/or longitudinal bone growth. As such, it is imperative that we further our understanding of the underpinning molecular mechanisms involved in such disorders so as to provide advances towards human and animal patient benefit. The mouse metatarsal organ explant culture is a highly physiological ex vivo model for studying endochondral ossification and bone growth as the growth rate of the bones in culture mimic that observed in vivo. Uniquely, the metatarsal organ culture allows the examination of chondrocytes in different phases of chondrogenesis and maintains cell-cell and cell-matrix interactions, therefore providing conditions closer to the in vivo situation than cells in monolayer or 3D culture. This protocol describes in detail the intricate dissection of embryonic metatarsals from the hind limb of E15 murine embryos and the subsequent analyses that can be performed in order to examine endochondral ossification and longitudinal bone growth.

We present a protocol to dissect and culture embryonic day 15 (E15) murine metatarsal bones. This highly physiological ex vivo model of endochondral ossification provides conditions closer to the in vivo situation than cells in monolayer or 3D culture and is a vital tool for investigating bone growth and development.

The fundamental process of endochondral ossification is under tight regulation in the healthy individual so as to prevent disturbed development and/or ...

Dissection and Coronal Slice Preparation of Developing Mouse Pituitary Gland

The pituitary gland or hypophysis is an important endocrine organ secreting hormones essential for homeostasis. It consists of two glands with separate embryonic origins and functions &#8212; the neurohypophysis and the adenohypophysis. The developing mouse pituitary gland is tiny and delicate with an elongated oval shape. A coronal section is preferred to display both the adenohypophysis and neurohypophysis in a single slice of the mouse pituitary.
The goal of this protocol is to achieve proper pituitary coronal sections with well-preserved tissue architectures from developing mice. In this protocol, we describe in detail how to dissect and process pituitary glands properly from developing mice. First, mice are fixed by transcardial perfusion of formaldehyde prior to dissection. Then three different dissecting techniques are applied to obtain intact pituitary glands depending on the age of mice. For fetal mice aged embryonic days (E) 17.5 - 18.5 and neonates up to 4 days, the entire sella regions including the sphenoid bone, gland, and trigeminal nerves are dissected. For pups aged postnatal days (P) 5 - 14, the pituitary glands connected with trigeminal nerves are dissected as a whole. For mice over 3 weeks old, the pituitary glands are carefully dissected free from the surrounding tissues. We also display how to embed the pituitary glands in a proper orientation by using the surrounding tissues as landmarks to obtain satisfying coronal sections. These methods are useful in analyzing histological and developmental features of pituitary glands in developing mice.

We present a protocol to dissect pituitary glands and prepare pituitary coronal sections from developing mice.

The pituitary gland or hypophysis is an important endocrine organ secreting hormones essential for homeostasis. It consists of two glands with separate ...

Dissection and Staining of Drosophila Pupal Ovaries

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a pupal case. The challenge of dissecting pupal ovaries also lies in their physical location within the pupa: the ovaries are surrounded by fat body cells inside the pupal abdomen, and these fat cells must be removed to allow for proper antibody staining. To overcome these challenges, this protocol utilizes customized Pasteur pipets to extract fat body cells from the pupal abdomen. Moreover, a chambered coverglass is used in place of a microcentrifuge tube during the staining process to improve visibility of the pupae. However, despite these and other advantages of the tools used in this protocol, successful execution of these techniques may still involve several days of practice due to the small size of pupal ovaries. The techniques outlined in this protocol could be applied to time course experiments in which ovaries are analyzed at various stages of pupal development.

Dissection and Staining of Drosophila Pupal Ovaries

The Drosophila ovary is an excellent model system for studying stem cell niche development. Though methods for dissecting larval and adult ovaries have been published, pupal ovary dissections require different techniques that have not been published in detail. Here we outline a protocol for dissecting, staining, and mounting pupal ovaries.

Unlike adult Drosophila ovaries, pupal ovaries are relatively difficult to access and examine due to their small size, translucence, and encasing within a ...

Organotypic Culture Method to Study the Development Of Embryonic Chicken Tissues

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ideal for experimentation. Currently, the study of these developmental pathways in the chicken embryo is conducted by applying inhibitors and drugs at localized sites and at low concentrations using a variety of methods. In vitro tissue&#160;culturing is a technique that enables the study of tissues separated from the host organism, while simultaneously bypassing many of the physical limitations present when working with whole embryos, such as the susceptibility of embryos to high doses of potentially lethal chemicals. Here, we present an organotypic culturing protocol for culturing the embryonic chicken half head in vitro, which presents new opportunities for the examination of developmental processes beyond the currently established methods.

Here, we present an organotypic culturing protocol to grow embryonic chicken organs in vitro. Using this method, the development of embryonic chicken tissue can be studied, while maintaining a high degree of control over the culture environment.

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ...

Dissection, Culture and Analysis of Primary Cranial Neural Crest Cells from Mouse for the Study of Neural Crest Cell Delamination and Migration

Over the past several decades there has been an increased availability of genetically modified mouse models used to mimic human pathologies. However, the ability to study cell movements and differentiation in vivo is still very difficult. Neurocristopathies, or disorders of the neural crest lineage, are particularly challenging to study due to a lack of accessibility of key embryonic stages and the difficulties in separating out the neural crest mesenchyme from adjacent mesodermal mesenchyme. Here, we set out to establish a well-defined, routine protocol for the culture of primary cranial neural crest cells. In our approach we dissect out the mouse neural plate border during the initial neural crest induction stage. The neural plate border region is explanted and cultured. The neural crest cells form in an epithelial sheet surrounding the neural plate border, and by 24 h after explant, begin to delaminate, undergoing an epithelial-mesenchymal transition (EMT) to become fully motile neural crest cells. Due to our two-dimensional culturing approach, the distinct tissue populations (neural plate versus premigratory and migratory neural crest) can be readily distinguished. Using live imaging approaches, we can then identify changes in neural crest induction, EMT and migratory behaviors. The combination of this technique with genetic mutants will be a very powerful approach for understanding normal and pathological neural crest cell biology.

This protocol describes the dissection and culture of cranial neural crest cells from mouse models, primarily for the study of cell migration. We describe the live imaging techniques used and the analysis of speed and cell shape changes.

Over the past several decades there has been an increased availability of genetically modified mouse models used to mimic human pathologies. However, the ...