The work was supported by core funding from the Medical Research Council and from Medical Research Scotland, grant award 436_FRG_L_1006. We are grateful to Craig Nicol for preparing technical drawings. We are grateful to Matthew Pearson and Paul Perry for their imaging support.

All animal work was performed in accordance with institutional guidelines under license by the UK Home Office (project license number PPL 60/3785 and 60/4424).
1. Preparation
<ol>
	<li>Label the melanoblasts in the developing skin by combining an appropriate Cre-recombinase expressing mouse line with a fluorescent reporter mouse line. Tyr::CreA, Tyr::CreB8 and Wnt1::Cre14 have been used successfully as Cre-expressing lines and R26YFPR9 as a reporter line.</li>
	<li>Prepare the culture medium in a laminar flow hood; supplement Dulbecco&#39;s Modified Eagle Medium (DMEM) with (1% v/v Penicillin/Streptomycin), 10% v/v fetal calf serum and 0.584 gm/L L-glutamine.</li>
	<li>The live imaging apparatus is outlined in Figure 1 Sterilize the imaging chamber base by wiping down with 70% ethanol. Sterilize the inserts, imaging clips, and O-rings by soaking overnight in 70% ethanol. Use a sterile lid from a 6-well plate as the lid of the chamber.</li>
	<li>The bottom surface of the imaging chamber consists of a lummox membrane held in place by an O-ring (Figure&#160;1). Start with a 35 mm gas permeable lummox dish. Place the dish over the imaging chamber and cut out the gas permeable membrane with a single edged razor blade. Push the O-ring over the membrane to secure it to the imaging chamber.</li>
	<li>The imaging clips (6 in total) clamp the embryonic skin in place (Figure 1) before use they must be filled with 1% agarose. Prepare&#160;a 2% solution of agarose with sterile dH2O by microwaving and cooling to 60 &#176;C. Mix 1:1 with 10 ml culture medium (see step 2) preheated to 60 &#176;C. Stand the 6 imaging clips in a sterile 6-well plate. Drip the 1% agarose solution into the center of each clip using a fine pastette and allow to cool. Add 1 ml cold sterile PBS to each well to prevent the agarose from drying out. The imaging clips can be stored for several hours in PBS.</li>
	<li>To carry out the delicate separation of embryonic skin and to handle the dissected tissue use the &#39;hair stick method&#39; as described in Kashiwagi et al.3&#160;Instead of using a chopstick a bamboo kebab skewer can be used. Make a small slit in the flat end of the skewer using a single edged razor blade and insert a soft toothbrush bristle. Trim the skewer so that it is approximately 15 cm in length.</li>
	<li>Use a confocal microscope with a full environmental chamber or stage top chamber providing 5% CO2 in air. Prewarm the microscope stage to 37 &#176;C for at least 1 hr prior to imaging. This helps to prevent sample drift caused by expansion of the stage components as they warm up.</li>
	<li>Prepare a multi-position set using the microscope&#39;s control software so that one can quickly and easily center on the middle of each culture to set up an experiment.</li>
</ol>
2. Procedure
<ol>
	<li>Mate the mice and designate the first day post coitum as day E0.5. At day E14.5, cull the female by cervical dislocation and expose the body cavity by making a small midline incision, pulling apart the skin towards the head and tail and then cutting the underlying peritoneum and pealing back to either side of the body. Dissect the uterus into cold sterile PBS by holding firmly with forceps and snipping along the mesometrium using surgical scissors. Keep the uterus on ice until required. For a detailed description see Shea&#160;et al.&#160;(2007)15.</li>
	<li>Dissect embryos from the uterus by first cutting the length of the uterine wall with surgical scissors to release the decidua and then dissecting the embryos from the decidua by pulling them apart with two pairs of fine forceps. Screen for fluorescent reporter expression (if necessary).</li>
	<li>Cull embryos by decapitation prior to dissection. Subsequently remove the tail and hind limbs and then the forelimbs using a single edged razor blade. Retain tissue for genotyping if required.</li>
	<li>Make an incision in the ventrum close to the midline in a rostro-caudal direction. Using the hair sticks described in step 1.6, carefully tease away the skin from the underlying connective tissue rotating the embryo at the same time. Do not remove the skin completely but rather leave it attached along the ventral edge furthest from the first incision.</li>
	<li>It is important not to let the skin become screwed up as it is then very difficult to mount. To prevent this, flatten out the skin using the hair sticks (dermal side up) on the surface of a dry Petri dish and then cut away from the embryo trunk using a single edged razor blade. The dermal side can be distinguished from the epidermal side by careful observation of the junction between the dissected tissue and the embryo before the skin is removed. The area of the dissected tissue is approximately 0.5 mm2 when dissecting an E14.5 embryo.</li>
	<li>Place an imaging clip on top of the skin so that the agarose is touching the dermal side of the tissue. Allow to stand for 60 sec&#160;and then carefully tease the edges of the tissue up the sides of the clip. Invert the clip and use the hair sticks to flatten out the skin and remove any air bubbles, taking care to touch the surface of the tissue (in the area that will be imaged) as little as possible.</li>
	<li>Use silk suture thread to tie the skin to the imaging clip using two simple thumb knots on either side of the imaging clip so that they tighten and pull the skin into the groove close to the top of the clip. Invert the clip, push inside the imaging insert and place in the base. Fill the insert with ~5 ml of culture medium (see step 1.2). Figure 1 outlines the assembly of the imaging chamber.</li>
	<li>Repeat Protocol for the remaining 5 samples.</li>
</ol>
3. Live Imaging
<ol>
	<li>The imaging chamber has the same dimensions as a standard 6-well plate. Use an appropriate plate insert to mount the chamber on the stage of the confocal microscope.</li>
	<li>An automated stage is required to image the cultures in parallel. Define the six positions to image in the confocal software. The exact settings will depend on the capability of the microscope used. Typically a small z-stack (3-5 z-positions to account for any stage drift) is used in each of the 6-positions and a z-stack is captured every 2&#160;min&#160;for 18-24 hr. For live-imaging applications it is generally advantageous to use a wider than optically optimal pinhole setting to reduce laser power and the number of z-sections required.</li>
</ol>

<ol>
	<li>Thomas, A. J., 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=The+making+of+a+melanocyte:+the+specification+of+melanoblasts+from+the+neural+crest.">The making of a melanocyte: the specification of melanoblasts from the neural crest.</a> Pigment Cell &amp; Melanoma Research. 21 (6), 598-610 (2008).</li><li>Mayer, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+migratory+pathway+of+neural+crest+cells+into+the+skin+of+mouse+embryos.">The migratory pathway of neural crest cells into the skin of mouse embryos.</a> Developmental Biology. 34 (1), 39-46 (1973).</li><li>Kashiwagi, M., Huh, N., Turksen, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organ+Culture+of+Developing+Mouse+Skin+and+Its+Application+for+Molecular+Mechanistic+Studies+of+Morphogenesis.">Organ Culture of Developing Mouse Skin and Its Application for Molecular Mechanistic Studies of Morphogenesis.</a> Epidermal Cells: Methods and Protocols. 289, 39-45 (2005).</li><li>Kashiwagi, M., Kuroki, T., Huh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specific+inhibition+of+hair+follicle+formation+by+epidermal+growth+factor+in+an+organ+culture+of+developing+mouse+skin.">Specific inhibition of hair follicle formation by epidermal growth factor in an organ culture of developing mouse skin.</a> Developmental Biology. 189 (1), 22-32 (1997).</li><li>Van Der Wel, L. I., Wei, L., Prens, E. P., Laman, J. D., Companjen, A. 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+modified+ex+vivo+skin+organ+culture+system+for+functional+studies.">A modified ex vivo skin organ culture system for functional studies.</a> Archives of Dermatological Research. 293 (4), 184-190 (2001).</li><li>Mort, R. L., Hay, L., Jackson, I. J. <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+live+imaging+of+melanoblast+migration+in+embryonic+mouse+skin.">Ex vivo live imaging of melanoblast migration in embryonic mouse skin.</a> Pigment Cell &amp; Melanoma Research. 23 (2), 299-301 (2010).</li><li>Jordan, S. A. A., Jackson, I. J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MGF+(KIT+ligand)+is+a+chemokinetic+factor+for+melanoblast+migration+into+hair+follicles.">MGF (KIT ligand) is a chemokinetic factor for melanoblast migration into hair follicles.</a> Developmental Biology. 225 (2), 424-436 (2000).</li><li>Delmas, V., Martinozzi, S., Bourgeois, Y., Holzenberger, M., Larue, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cre-mediated+recombination+in+the+skin+melanocyte+lineage.">Cre-mediated recombination in the skin melanocyte lineage.</a> Genesis. 36 (2), 73-80 (2003).</li><li>Srinivas, S., 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=Cre+reporter+strains+produced+by+targeted+insertion+of+EYFP+and+ECFP+into+the+ROSA26+locus.">Cre reporter strains produced by targeted insertion of EYFP and ECFP into the ROSA26 locus.</a> BMC Developmental Biology. 1 (1), (2001).</li><li>Li, A., 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=Rac1+Drives+Melanoblast+Organization+during+Mouse+Development+by+Orchestrating+Pseudopod.">Rac1 Drives Melanoblast Organization during Mouse Development by Orchestrating Pseudopod.</a> Driven Motility and Cell-Cycle Progression. Developmental Cell. 21 (4), 722-734 (2011).</li><li>Li, A., 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=Activated+Mutant+NRas(Q61K)+Drives+Aberrant+Melanocyte+Signaling,+Survival,+and+Invasiveness+via+a+Rac1-Dependent+Mechanism.">Activated Mutant NRas(Q61K) Drives Aberrant Melanocyte Signaling, Survival, and Invasiveness via a Rac1-Dependent Mechanism.</a> The Journal of Investigative Dermatology. , 1-12 (2012).</li><li>Schachtner, 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=Tissue+inducible+Lifeact+expression+allows+visualization+of+actin+dynamics+in+vivo+and+ex+vivo.">Tissue inducible Lifeact expression allows visualization of actin dynamics in vivo and ex vivo.</a> European Journal of Cell Biology. 91 (11-12), 923-929 (2012).</li><li>Ma, Y., 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=Fascin+1+is+transiently+expressed+in+mouse+melanoblasts+during+development+and+promotes+migration+and+proliferation.">Fascin 1 is transiently expressed in mouse melanoblasts during development and promotes migration and proliferation.</a> Development. 140 (10), 2203-2211 (2013).</li><li>Danielian, P. S., Muccino, D., Rowitch, D. H., Michael, S. K., McMahon, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modification+of+gene+activity+in+mouse+embryos+in+utero+by+a+tamoxifen-inducible+form+of+Cre+recombinase.">Modification of gene activity in mouse embryos in utero by a tamoxifen-inducible form of Cre recombinase.</a> Current Biology. 8 (24), 1323-1326 (1998).</li><li>Shea, K., Geijsen, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+6.5+dpc+mouse+embryos.">Dissection of 6.5 dpc mouse embryos.</a> Journal of Visualized Experiments. (2), (2007).</li></ol>

The authors have nothing to disclose.

We describe a method to culture embryonic skin that is particularity amenable to live-cell imaging on inverted confocal microscopes. The method includes recent improvements that allow 6 cultures to be imaged in parallel and removes the reliance on matrigel and Nuclepore membranes of the original method6. The crucial technical difference from similar techniques is the use of a gas-permeable lummox membrane to establish an air liquid interface and also to act as a coverslip. We have successfully maintained the c...

Traditionally embryonic skin has been cultured by dissecting from the mouse embryo and mounting on a polycarbonate Nuclepore membrane. The membrane is then floated on culture medium, thus maintaining an air-liquid interface across the surface of the developing tissue3,4. This technique has been used to assay melanoblast behavior by fixing the tissue and assessing melanoblast distribution using &#946;-galactosidase as a marker7. We have developed a method that allows live-imaging of fluorescently labeled melanoblasts in ex vivo skin culture6. Here we describe the method in detail from dissection, to setup, to live confocal imaging and include some recent improvements.
Melanoblasts are the embryonic precursors of melanocytes, the cells that produce pigment in hair and skin. Melanoblasts arise in the neural crest adjacent to the neural tube at around embryonic day 9 (E9) in the developing mouse embryo. Subsequently they migrate along a dorsolateral pathway between the ectoderm and the developing somites. At E12.5 they move from the dermis to the epidermis where they proliferate and continue their migration. The primary hair follicle pattern begins to form in the epidermis at E14.5 and by E15.5 melanoblasts are localizing to these follicles. For a review of melanoblast/melanocyte development see Thomas &#38; Erickson (2008)1. In order to label the melanoblast population we have combined Tyr::CreB animals that express Cre-recombinase driven by the mouse tyrosinase promoter8 with R26YFPR animals that express yellow fluorescent protein (YFP) conditionally from the ROSA26 locus9.
We describe a method to culture embryonic skin and capture images using an inverted confocal microscope. It is adapted form the original method described in Mort&#160;et al.&#160;(2010)6. The present method allows imaging in a 6-well format and removes the reliance on Nuclepore membranes and on matrigel to support the culture. Instead using a small block of 1% agarose to stabilize the embryonic skin. Removing the reliance on matrigel is important especially in situations where the response of the embryonic skin to soluble growth factors is the focus of study. Our original method has already been used to gain new insights into melanoblast development10-13 and we anticipate that the improvements we describe here will make it more powerful as an experimental technique especially where multiple parallel cultures are a requirement.

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	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DMEM high glucose</td>
			<td style="width:132px;">Biochrom AG</td>
			<td style="width:119px;">F0475</td>
			<td style="width:167px;">without phenol red</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Penicillin</td>
			<td style="width:132px;">Sigma</td>
			<td style="width:119px;">P3032</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Streptomycin</td>
			<td style="width:132px;">Sigma</td>
			<td style="width:119px;">S9137</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fetal calf serum</td>
			<td style="width:132px;">Hyclone</td>
			<td style="width:119px;">SV30160.03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glutamax</td>
			<td style="width:132px;">Gibco</td>
			<td style="width:119px;">35050-038</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethanol</td>
			<td style="width:132px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Live imaging chamber</td>
			<td style="width:132px;">Custom made</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Lummox dishes</td>
			<td style="width:132px;">Sarstedt</td>
			<td style="width:119px;">94.6077.410</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">6-well plate</td>
			<td style="width:132px;">Greiner Bio-One</td>
			<td style="width:119px;">657-160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Single edged razor blade</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:119px;">1244-3170</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Agarose</td>
			<td style="width:132px;">Biogene</td>
			<td style="width:119px;">300-300</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fine pastette</td>
			<td style="width:132px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PBS</td>
			<td style="width:132px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Kebab skewers</td>
			<td style="width:132px;">Waitrose</td>
			<td style="width:119px;"></td>
			<td>Bamboo BBQ skewers 30cm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Toothbrush</td>
			<td style="width:132px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Petri dishes</td>
			<td style="width:132px;">Greiner Bio-One</td>
			<td style="width:119px;">633185</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Suture thread</td>
			<td style="width:132px;">Look</td>
			<td style="width:119px;">SP115</td>
			<td>Black silk suture thread</td>
		</tr>
	</tbody>
</table>

ex vivo culture of mouse embryonic skin and live-imaging of melanoblast migration

Melanoblasts are the neural crest derived precursors of melanocytes; the cells responsible for producing the pigment in skin and hair. Melanoblasts migrate through the epidermis of the embryo where they subsequently colonize the developing hair follicles1,2. Neural crest cell migration is extensively studied in vitro but in vivo methods are still not well developed, especially in mammalian systems. One alternative is to use ex vivo organotypic culture3-6. Culture of mouse embryonic skin requires the maintenance of an air-liquid interface (ALI) across the surface of the tissue3,6. High resolution live-imaging of mouse embryonic skin has been hampered by the lack of a good method that not only maintains this ALI but also allows the culture to be inverted and therefore compatible with short working distance objective lenses and most confocal microscopes. This article describes recent improvements to a method that uses a gas permeable membrane to overcome these problems and allow high-resolution confocal imaging of embryonic skin in ex vivo culture6. By using a melanoblast specific Cre-recombinase expressing mouse line combined with the R26YFPR reporter line we are able to fluorescently label the melanoblast population within these skin cultures. The technique allows live-imaging of melanoblasts and observation of their behavior and interactions with the tissue in which they develop. Representative results are included to demonstrate the capability to live-image 6&#160;cultures in parallel.

Figure 2 shows representative results from a time lapse experiment using embryonic skin from Tyr::CreB x R26YFPR embryos at E14.5. 6 embryonic skin cultures were imaged by confocal microscopy every 2&#160;min&#160;for 18 hr. The freeware image analysis software package ImageJ was used to analyze the behavior of the YFP-labeled melanoblasts in the 6 movies. The melanoblasts were automatically tracked using the wrMTrck plugin developed by Jesper S&#248;ndergaard Pedersen (<a href="http://www.phage...

Watch this Scientific Journal Video about Ex vivo Culture of Mouse Embryonic Skin and Live-imaging of Melanoblast Migration at JoVE.com

Ex vivo Culture of Mouse Embryonic Skin and Live-imaging of Melanoblast Migration

We describe the dissection and ex vivo culture of mouse embryonic skin. The culture system maintains an air-liquid interface across the tissue surface and allows imaging on an inverted microscope. Melanoblasts, a component of the developing skin, are fluorescently labeled allowing their behavior to be observed using confocal microscopy.

Ex vivo Culture of Mouse Embryonic Skin and Live-imaging of Melanoblast Migration

Melanoblasts are the neural crest derived precursors of melanocytes; the cells responsible for producing the pigment in skin and hair. Melanoblasts ...

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12.5K Views.  University of Edinburgh. We describe the dissection and ex vivo culture of mouse embryonic skin. The culture system maintains an air-liquid interface across the tissue surface and allows imaging on an inverted microscope. Melanoblasts, a component of the developing skin, are fluorescently labeled allowing their behavior to be observed using confocal microscopy.

Video: Ex vivo Culture of Mouse Embryonic Skin and Live-imaging of Melanoblast Migration

Method for Culture of Early Chick Embryos ex vivo (New Culture)

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  the formation and patterning of brain, neural tube, somite and heart primordia. Applications of chick embryo culture include electroporation of DNA or RNA constructs in order to analyze gene function, grafts of growth factor coated beads such as FGFs and BMPs , as well as whole mount in situ hybridization and immunohistochemistry. This video demonstrates the different steps in chick embryo culture; First, the embryo is explanted in saline. Then, the embryo is centered on a glass ring. The membranes surrounding the embryo are lifted along the walls of the ring. The ring is then placed in a culture dish containing a pool of albumine. The culture dish is sealed and placed in a humid chamber, where the embryo is cultured for up to 24 hrs. Finally, the embryo is removed from the ring, fixed and processed for further applications. A troubleshooting guide is also presented.

Method for Culture of Early Chick Embryos ex vivo New Culture

This video demonstrates New culture, a method by which chick embryos are cultured outside the egg for up to 24 hr. This method enables one to study early development (primitive streak to 14 som.), a period corresponding to E7-9 in mouse. Applications of this technique include electroporation, in situ hybridization and immunohistochemistry.

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ...

Live Imaging of Glial Cell Migration in the Drosophila Eye Imaginal Disc

Glial cells of both vertebrate and invertebrate organisms must migrate to final target regions in order to ensheath and support associated neurons. While recent progress has been made to describe the live migration of glial cells in the developing pupal wing (1), studies of Drosophila glial cell migration have typically involved the examination of fixed tissue. Live microscopic analysis of motile cells offers the ability to examine cellular behavior throughout the migratory process, including determining the rate of and changes in direction of growth. Paired with use of genetic tools, live imaging can be used to determine more precise roles for specific genes in the process of development. Previous work by Silies et al. (2) has described the migration of glia originating from the optic stalk, a structure that connects the developing eye and brain, into the eye imaginal disc in fixed tissue. Here we outline a protocol for examining the live migration of glial cells into the Drosophila eye imaginal disc. We take advantage of a Drosophila line that expresses GFP in developing glia to follow glial cell progression in wild type and in mutant animals.

Here we describe a protocol to examine the migration of glial cells into the developing Drosophila eye using live microscopic analysis paired with GFP tagged glial cells.

Glial cells of both vertebrate and invertebrate organisms must migrate to final target regions in order to ensheath and support associated neurons.  While ...

Live Imaging of the Zebrafish Embryonic Brain by Confocal Microscopy

In this video, we demonstrate the method our lab has developed to analyze the cell shape changes and rearrangements required to bend and fold the developing zebrafish brain (Gutzman et al, 2008). Such analysis affords a new understanding of the underlying cell biology required for development of the 3D structure of the vertebrate brain, and significantly increases our ability to study neural tube morphogenesis. The embryonic zebrafish brain is shaped beginning at 18 hours post fertilization (hpf) as the ventricles within the neuroepithelium inflate. By 24 hpf, the initial steps of neural tube morphogenesis are complete. Using the method described here, embryos at the one cell stage are injected with mRNA encoding membrane-targeted green fluorescent protein (memGFP). After injection and incubation, the embryo, now between 18 and 24 hpf, is mounted, inverted, in agarose and imaged by confocal microscopy. Notably, the zebrafish embryo is transparent making it an ideal system for fluorescent imaging. While our analyses have focused on the midbrain-hindbrain boundary and the hindbrain, this method could be extended for analysis of any region in the zebrafish to a depth of 
80-100 &mu;m.

In this video, we demonstrate a method by which to analyze the developing vertebrate brain in live zebrafish embryos at single cell resolution by confocal microscopy. This includes the method by which we inject the single-cell zebrafish embryo and subsequently mount and image the developing brain.

In this video, we demonstrate the method our lab has developed to analyze the cell shape changes and rearrangements required to bend and fold the ...

Live Imaging Of Drosophila melanogaster Embryonic Hemocyte Migrations

Many studies address cell migration using in vitro methods, whereas the physiologically relevant environment is that of the organism itself. Here we present a protocol for the mounting of Drosophila melanogaster embryos and subsequent live imaging of fluorescently labeled hemocytes, the embryonic macrophages of this organism. Using the Gal4-uas system1 we drive the expression of a variety of genetically encoded, fluorescently tagged markers in hemocytes to follow their developmental dispersal throughout the embryo. Following collection of embryos at the desired stage of development, the outer chorion is removed and the embryos are then mounted in halocarbon oil between a hydrophobic, gas-permeable membrane and a glass coverslip for live imaging. In addition to gross migratory parameters such as speed and directionality, higher resolution imaging coupled with the use of fluorescent reporters of F-actin and microtubules can provide more detailed information concerning the dynamics of these cytoskeletal components.

Live Imaging Of Drosophila melanogaster Embryonic Hemocyte Migrations

Drosophila hemocytes disperse over the entirety of the developing embryo. This protocol demonstrates how to mount and image these migrations using embryos with fluorescently labelled hemocytes.

Many studies address cell migration using in vitro methods, whereas the physiologically relevant environment is that of the organism itself. Here we ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and uterine carcinomas, where death rates have fallen in recent years, ovarian cancer cure rates have remained relatively unchanged over the past two decades 1. This is largely due to the lack of appropriate screening tools for detection of early stage disease where surgery and chemotherapy are most effective 2, 3. As a result, most patients present with advanced stage disease and diffuse abdominal involvement. This is further complicated by the fact that ovarian cancer is a heterogeneous disease with multiple histologic subtypes 4, 5. Serous ovarian carcinoma (SOC) is the most common and aggressive subtype and the form most often associated with mutations in the BRCA genes. Current experimental models in this field involve the use of cancer cell lines and mouse models to better understand the initiating genetic events and pathogenesis of disease 6, 7. Recently, the fallopian tube has emerged as a novel site for the origin of SOC, with the fallopian tube (FT) secretory epithelial cell (FTSEC) as the proposed cell of origin 8, 9. There are currently no cell lines or culture systems available to study the FT epithelium or the FTSEC. Here we describe a novel ex vivo culture system where primary human FT epithelial cells are cultured in a manner that preserves their architecture, polarity, immunophenotype, and response to physiologic and genotoxic stressors. This ex vivo model provides a useful tool for the study of SOC, allowing a better understanding of how tumors can arise from this tissue, and the mechanisms involved in tumor initiation and progression.

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

The fallopian tube (FT) is emerging as an alternative site of origin for serous ovarian carcinoma (SOC). This protocol describes a novel method for the isolation and ex vivo culture of fallopian tube epithelial cells. This system recapitulates the in vivo epithelium and allows the study of SOC pathogenesis.

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and ...

A System for ex vivo Culturing of Embryonic Pancreas

The pancreas controls vital functions of our body, including the production of digestive enzymes and regulation of blood sugar levels1. Although in the past decade many studies have contributed to a solid foundation for understanding pancreatic organogenesis, important gaps persist in our knowledge of early pancreas formation2. A complete understanding of these early events will provide insight into the development of this organ, but also into incurable diseases that target the pancreas, such as diabetes or pancreatic cancer. Finally, this information will generate a blueprint for developing cell-replacement therapies in the context of diabetes.
 During embryogenesis, the pancreas originates from distinct embryonic outgrowths of the dorsal and ventral foregut endoderm at embryonic day (E) 9.5 in the mouse embryo3,4. Both outgrowths evaginate into the surrounding mesenchyme as solid epithelial buds, which undergo proliferation, branching and differentiation to generate a fully mature organ2,5,6. Recent evidences have suggested that growth and differentiation of pancreatic cell lineages, including the insulin-producing &beta;-cells, depends on proper tissue-architecture, epithelial remodeling and cell positioning within the branching pancreatic epithelium7,8. However, how branching morphogenesis occurs and is coordinated with proliferation and differentiation in the pancreas is largely unknown. This is in part due to the fact that current knowledge about these developmental processes has relied almost exclusively on analysis of fixed specimens, while morphogenetic events are highly dynamic.
 Here, we report a method for dissecting and culturing mouse embryonic pancreatic buds ex vivo on glass bottom dishes, which allow direct visualization of the developing pancreas (Figure 1). This culture system is ideally devised for confocal laser scanning microscopy and, in particular, live-cell imaging. Pancreatic explants can be prepared not only from wild-type mouse embryos, but also from genetically engineered mouse strains (e.g. transgenic or knockout), allowing real-time studies of mutant phenotypes. Moreover, this ex vivo culture system is valuable to study the effects of chemical compounds on pancreatic development, enabling to obtain quantitative data about proliferation and growth, elongation, branching, tubulogenesis and differentiation. In conclusion, the development of an ex vivo pancreatic explant culture method combined with high-resolution imaging provides a strong platform for observing morphogenetic and differentiation events as they occur within the developing mouse embryo.

A System for ex vivo Culturing of Embryonic Pancreas

Here, we describe a method for isolation, culture and manipulation of mouse embryonic pancreas. This represents an excellent ex vivo system for studying various aspects of pancreatic development, including morphogenesis, differentiation and growth. Pancreatic bud explants can be cultured for several days and used in a range of different applications, including whole-mount immunofluorescence and live imaging.

The pancreas controls vital functions of our body,  including the production of digestive enzymes and regulation of blood sugar  levels1. Although in the ...

A Novel Ex vivo Culture Method for the Embryonic Mouse Heart

Developmental studies in the mouse are hampered by the inaccessibility of the embryo during gestation. Thus, protocols to isolate and culture individual organs of interest are essential to provide a method of both visualizing changes in development and allowing novel treatment strategies. To promote the long-term culture of the embryonic heart at late stages of gestation, we developed a protocol in which the excised heart is cultured in a semi-solid, dilute Matrigel. This substrate provides enough support to maintain the three-dimensional structure but is flexible enough to allow continued contraction. In brief, hearts are excised from the embryo and placed in a mixture of cold Matrigel diluted 1:1 with growth medium. After the diluted Matrigel solidifies, growth medium is added to the culture dish. Hearts excised as late as embryonic day 16.5 were viable for four days post-dissection. Analysis of the coronary plexus shows that this method does not disrupt coronary vascular development. Thus, we present a novel method for long-term culture of embryonic hearts.

A Novel Ex vivo Culture Method for the Embryonic Mouse Heart

Developmental studies in the mouse are hampered by the inaccessibility of the embryo during gestation. To promote the long-term culture of the embryonic heart at late stages of gestation, we developed a protocol in which the excised heart is cultured in a semi-solid, dilute Matrigel.

Developmental studies in the mouse are hampered  by the inaccessibility of the embryo during gestation. Thus, protocols to  isolate and culture individual ...

Mouse Fetal Whole Intestine Culture System for Ex Vivo Manipulation of Signaling Pathways and Three-dimensional Live Imaging of Villus Development

Most morphogenetic processes in the fetal intestine have been inferred from thin sections of fixed tissues, providing snapshots of changes over developmental stages. Three-dimensional information from thin serial sections can be challenging to interpret because of the difficulty of reconstructing serial sections perfectly and maintaining proper orientation of the tissue over serial sections. Recent findings by Grosse et al., 2011 highlight the importance of three- dimensional information in understanding morphogenesis of the developing villi of the intestine1. Three-dimensional reconstruction of singly labeled intestinal cells demonstrated that the majority of the intestinal epithelial cells contact both the apical and basal surfaces. Furthermore, three-dimensional reconstruction of the actin cytoskeleton at the apical surface of the epithelium demonstrated that the intestinal lumen is continuous and that secondary lumens are an artifact of sectioning. Those two points, along with the demonstration of interkinetic nuclear migration in the intestinal epithelium, defined the developing intestinal epithelium as a pseudostratified epithelium and not stratified as previously thought1. The ability to observe the epithelium three-dimensionally was seminal to demonstrating this point and redefining epithelial morphogenesis in the fetal intestine. With the evolution of multi-photon imaging technology and three-dimensional reconstruction software, the ability to visualize intact, developing organs is rapidly improving. Two-photon excitation allows less damaging penetration deeper into tissues with high resolution. Two-photon imaging and 3D reconstruction of the whole fetal mouse intestines in Walton et al., 2012 helped to define the pattern of villus outgrowth2. Here we describe a whole organ culture system that allows ex vivo development of villi and extensions of that culture system to allow the intestines to be three-dimensionally imaged during their development.

Mouse Fetal Whole Intestine Culture System for Ex Vivo Manipulation of Signaling Pathways and Three-dimensional Live Imaging of Villus Development

Improved imaging technology is allowing three-dimensional imaging of organs during development. Here we describe a whole organ culture system that allows live imaging of the developing villi in the fetal mouse intestine.

Most morphogenetic processes in the fetal intestine have been inferred from thin sections of fixed tissues, providing snapshots of changes over ...

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a versatile analytical tool for characterizing viscoelastic mechanical properties for a variety of materials ranging from hard (plastic, glass, metal, etc.) surfaces to cells on any substrate. It has been widely used to measure the stiffness of cells, but less frequently used to measure the stiffness of aortas. In this paper, we will describe the procedures for using AFM in contact mode to measure the ex vivo elastic modulus of unloaded mouse arteries. We describe our procedure for isolation of mouse aortas, and then provide detailed information for the AFM analysis. This includes step-by-step instructions for alignment of the laser beam, calibration of the spring constant and deflection sensitivity of the AFM probe, and acquisition of force curves. We also provide a detailed protocol for data analysis of the force curves.

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

We present detailed protocols for isolation of aortas from mouse and measurement of their elastic modulus using atomic force microscopy.

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a ...