Les auteurs tiennent à remercier Irene Choi pour illustrer les chefs d&#39;embryons dans la figure 1 et les autres membres du laboratoire de l&#39;aide et de discussion. Ce travail est soutenu par le NIH subvention DE012728 (TW)

1. Préparer dispase II <ol><li> Préparer une nouvelle solution saline tamponnée Hepes (EBM) (50 mM de HEPES / KOH à pH 7,4, NaCl 150 mM). Ajouter 2 ml 0,5 M HEPES / KOH pH 7,4 et 1,2 ml 2,5 M de NaCl dans 16,8 ml ultrapure H O. 2 </li><li> Faire 10 mg / ml dispase II. Peser 0,2 g dispase II (Roche, Cat # 4942078001) et dissoudre dans 20 ml de HBS. Préparer des aliquotes de 1,0 ml dans des tubes Eppendorf individuelles et conserver à -20 ° C pour stockage à long terme. </li><li> Diluer 10 mg / ml dispase II 1:10 dans PBS avant de les utiliser. Mettez le diluée dispase II sur la glace. </li></ol> 2. Disséquer CD-1 embryons E10.5 Femme enceinte de Toutes les expériences sur les animaux ont été effectuées conformément aux protocoles approuvés par le soin des animaux Université du Colorado à Denver (UCD) et le Comité d&#39;utilisation. Souris CD-1 (ICR) ont été obtenus auprès de Harlan Laboratories (Indianapolis, IN). <ol><li> Nettoyez la zone de dissection et les outils avec de l&#39;éthanol à 70%. </li><li> Euthanasier enceintes CD-1 femelles à l&#39;aide approuvantprotocoles éd. </li><li> Vaporiser l&#39;abdomen avec de l&#39;éthanol 70% puis ouvrez l&#39;abdomen. Utilisez un jeu de pinces pour tirer l&#39;utérus et l&#39;autre pour arracher le mésomètre de l&#39;utérus. Enlever l&#39;utérus du corps. Répétez l&#39;opération pour corne utérine de l&#39;autre côté de l&#39;abdomen. </li><li> Rincer brièvement l&#39;utérus avec PBS glacé dans un plat de 10 cm de Petri pour laver le sang. </li><li> Transfert de l&#39;utérus dans un nouveau plat de Pétri avec du PBS glacé. Séparer en un embryon de fragments en coupant entre les sites d&#39;implantation. </li><li> Transfert d&#39;un embryon dans du PBS glacé sous un stéréomicroscope. Utilisez une pince fine à arracher la paroi musculaire de l&#39;utérus à partir de l&#39;un des sites de coupe pour exposer l&#39;embryon avec le sac vitellin. Retirez le sac vitellin et l&#39;amnios. Transfert d&#39;embryons disséqué dans un plat de Pétri de 6 cm avec du PBS sur la glace. Continuez jusqu&#39;à ce que tous les embryons ont été collectés de cette façon. </li></ol> 3. Dispase II Traitement <ol><li> Lavez tous les embryons avec du PBS dans un plat de Pétri de 6 cm. RemplacerPBS avec 10 ml diluée dans du PBS II Dispase. Couvrir la boîte de Pétri et incuber à 37 ° C pendant 25 min - une infection bactérienne incubateur ou la pièce chaude devrait suffire - nous n&#39;avons pas utilisé de CO 2 incubateur de culture tissulaire pour cette étape. </li><li> Prenez la boîte de Pétri et observer l&#39;embryon sous un stéréomicroscope. L&#39;ectoderme aurait dû se détacher, caractérisée par un écart évident entre cette couche de tissu et le mésenchyme sous-jacent. Sinon, incuber pendant 5 minutes supplémentaires à 37 ° C. Ensuite, mettre la boîte de Pétri sur de la glace. </li></ol> 4. Disséquer les protubérances intactes du visage <ol><li> Utiliser une pipette de verre jetable (VWR, Cat # 14672-380) pour transférer un dispase II traités embryon dans du PBS glacé dans un plat de Pétri de 6 cm sous un stéréomicroscope. </li><li> Utilisez une paire de pinces pour tenir l&#39;embryon. Utilisez une autre paire de pinces fines pour couper soigneusement les limites des protubérances du visage attachés à la tête (figure 1 montre les limites deles saillies du visage). Commencer à partir d&#39;un côté de la MNP, puis le MxP, et le dernier FNP. Faites la même chose de l&#39;autre côté de disséquer les protubérances du visage sur intactes (figure 2A). </li></ol> 5. L&#39;ectoderme séparée du visage à partir de mésenchyme <ol><li> Respecter les protubérances du visage sous un stéréomicroscope avec distance de travail 3x. Utilisez un long pipette Pasteur en verre délicatement pipeter les proéminences du visage de haut en bas 5 fois. Après cela, l&#39;ectoderme est facile à décoller. </li><li> Utilisez une paire de pinces pour tenir les protubérances du visage. Utilisez l&#39;autre paire de pinces pour détacher l&#39;ectoderme très lentement. Figure 2B montre les feuilles séparées de l&#39;ectoderme facial. </li><li> Utiliser une nouvelle pipette Pasteur en verre longue de transférer l&#39;ectoderme facial dans un tube Eppendorf de 1,5 ml avec du PBS sur la glace. Transférer le mésenchyme dans un autre tube Eppendorf de 1,5 ml avec du PBS sur la glace. </li><li> Utilisez la nouvelle PBS glacé pour chaque dissection. Prélever des échantillons. </li><li> Laver til échantillons avec du PBS. Centrifuger à 4 ° C, 500 g pendant 3 min. </li><li> Aspirer le PBS à l&#39;aide de longues pipettes Pasteur en verre. Si les échantillons doivent être utilisés pour le dosage ChIP, passez à l&#39;étape 6.1. Pour l&#39;extraction d&#39;ARN, passez à l&#39;étape 6.2. Pour l&#39;extraction des protéines, passez à l&#39;étape 6.3. </li></ol> 6. Les échantillons pour l&#39;expérimentation de processus plus <ol><li> Les échantillons pour analyse ChIP <ol><li> Ajouter 1 ml de PBS avec du formaldéhyde à 1% de réticulation. Homogénéiser les échantillons. </li><li> Incuber à température ambiante pendant 10 min avec rotation. </li><li> Ajouter 110 ul de 1,25 M glycine dans chaque tube pour étancher formaldéhyde n&#39;ayant pas réagi. </li><li> Mélanger et incuber à température ambiante pendant 5 min. </li><li> Centrifuger à 500 xg à 4 ° C pendant 3 min. Retirer le surnageant. </li><li> Ajouter 1 ml de PBS froid pour laver les tissus. </li><li> Centrifuger à 500 xg à 4 ° C pendant 3 min. </li><li> Retirer du PBS et PBS laver une fois répéter. </li><li> Retirer le surnageant, Snap geler les tissus dans de l&#39;azote liquide. Rangez la samples à -80 ° C pour la mise en commun et le traitement ultérieur. </li></ol></li><li> Les échantillons destinés à l&#39;extraction d&#39;ARN <ol><li> Placez l&#39;ectoderme du visage et du mésenchyme dans des tubes contenant le RNAlater (Ambion). </li><li> Incuber les échantillons dans une solution RNAlater nuit à 4 ° C pour permettre la pénétration en profondeur des tissus. </li><li> Conserver à -20 ° C pour la mise en commun et le traitement ultérieur. </li></ol></li><li> Les échantillons destinés à l&#39;extraction des protéines </li></ol> Ajouter un tampon de lyse à l&#39;échantillon pour un traitement ultérieur. Ou prenez geler les tissus dans de l&#39;azote liquide. Stocker les échantillons à -80 ° C pendant la mise en commun et le traitement ultérieur. Remarques <ol><li> Les contraintes de temps. Prévoyez 4-6 heures à partir du début de la dissection jusqu&#39;au début de l&#39;article 6. </li><li> Lorsque compétent, il faut ~ 10-15 min par embryon d&#39;effectuer sections 4 et 5 (dissection importance et la séparation ectoderme). </li><li> Si les échantillons sont pour l&#39;ARN isolement, tous les solution doit être traité avec diéthylpyrocarbonate premier. Aussi nettoyer les pinces et la zone de travail avec RNase Away. </li><li> Conserver les échantillons sur la glace en tout temps sauf pour le traitement dispase II et dissections. Changer à nouveau PBS glacée pour chaque dissection pour s&#39;assurer que le PBS utilisé pour la dissection est froid. </li><li> Pinces pointues sont essentiels pour obtenir une dissection précise. Nettoyer la pince complètement pour éviter toute contamination. </li><li> Pour prélever des échantillons de différentes saillies, disséquer chaque proéminence séparément après dispase II de traitement. Puis séparer l&#39;ectoderme et le mésenchyme. </li><li> Après traitement à la dispase II, l&#39;ectoderme facial est facile à décoller. Portez une attention particulière à la contamination de l&#39;ectoderme autre. Jetez tous les tissus potentiellement contaminés. </li><li> Une fois que vous commencez, ne vous arrêtez pas jusqu&#39;à ce que les échantillons parviennent au point approprié dans la section 6. Terminer la séparation de l&#39;ectoderme facial et mésenchyme pour tous les embryons aussi rapidement que vous le pouvez. </li><li> L&#39;enzyme activités de dispase II peut être différent entre les lots et les marques. Il est nécessaire d&#39;ajuster le temps de traitement pour les différentes marques et les lots de dispase II. </li></ol>

<ol>
	<li>Wilkie, A. O., Morriss-Kay, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+of+craniofacial+development+and+malformation.">Genetics of craniofacial development and malformation.</a> Nat. Rev. Genet. 2, 458-468 (2001).</li><li>Gritli-Linde, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+2+-+The+Etiopathogenesis+of+cleft+lip+and+cleft+palate:+usefulness+and+caveats+of+mouse+models.">Chapter 2 - The Etiopathogenesis of cleft lip and cleft palate: usefulness and caveats of mouse models.</a> Current Topics in Developmental Biology. 84, 37-138 (2008).</li><li>Schutte, B. C., Murray, J. 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+many+faces+and+factors+of+orofacial+clefts.">The many faces and factors of orofacial clefts.</a> Human Molecular Genetics. 8, 1-7 (1999).</li><li>Chai, Y., Maxson, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+craniofacial+morphogenesis.">Recent advances in craniofacial morphogenesis.</a> Dev. Dyn. 235, 2353-2375 (2006).</li><li>Jiang, R., Bush, J. O., Lidral, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+upper+lip:+Morphogenetic+and+molecular+mechanisms.">Development of the upper lip: Morphogenetic and molecular mechanisms.</a> Dev. Dyn. 235, 1152-1166 (2006).</li><li>Reid, B. S., Yang, H., Melvin, V. S., Taketo, M. M., Williams, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ectodermal+WNT/&#946;-catenin+signaling+shapes+the+mouse+face.">Ectodermal WNT/&#946;-catenin signaling shapes the mouse face.</a> Developmental Biology. 349, 261-269 (2011).</li><li>Feng, W., 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=Spatial+and+temporal+analysis+of+gene+expression+during+growth+and+fusion+of+the+mouse+facial+prominences.">Spatial and temporal analysis of gene expression during growth and fusion of the mouse facial prominences.</a> PLoS ONE. 4, e8066 (2009).</li><li>Chia, R., Achilli, F., Festing, M. F., Fisher, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+origins+and+uses+of+mouse+outbred+stocks.">The origins and uses of mouse outbred stocks.</a> Nat. Genet. 37 (11), 1181-1186 (2005).</li><li>Nagai, T., Aruga, J., Takada, 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=The+expression+of+the+mouse+Zic1,+Zic2,+and+Zic3+gene+suggests+an+essential+role+for+Zic+genes+in+body+pattern+formation.">The expression of the mouse Zic1, Zic2, and Zic3 gene suggests an essential role for Zic genes in body pattern formation.</a> Developmental Biology. 182, 299-313 (1997).</li><li>Britsch, 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=The+transcription+factor+Sox10+is+a+key+regulator+of+peripheral+glial+development.">The transcription factor Sox10 is a key regulator of peripheral glial development.</a> Genes Dev. 15 (1), 66-78 (2001).</li></ol>

Les auteurs n&#39;ont aucun intérêt concurrents ou d&#39;autres conflits associés avec le contenu de cet article.

Ce protocole fournit une méthode simple pour séparer l&#39;ectoderme embryonnaire de la souris pour le visage et le mésenchyme basée sur une première étape de traitement dispase II. Dans des études antérieures, nous avons procédé à la dissection des protubérances du visage avant dispase II du traitement, mais nous avons toujours trouvé que le mésenchyme devient &quot;collante&quot; et plus difficile à manipuler. Notre nouveau protocole permet d&#39;éviter ce problème. Combinaison dispase II le traitemen...

<table>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments</td>
 </tr>
 <td>Dispase II (neutral protease, grade II)</td>
 <td>Roche</td>
 <td>4942078001</td>
 <td>Make 10 mg/ml Dispase II stock solution in HBS. Aliquot and store at -20 &deg;C . </td>
 </tr>
 <td>RNAlater</td>
 <td>Ambion</td>
 <td>AM7021</td>
 <td>&nbsp;</td>
 </tr>
</table>

separation of mouse embryonic facial ectoderm and mesenchyme

Fentes orofaciales sont les défauts les plus fréquents cranio-faciales, qui touchent 1,5 en 1000 1,2 nouveau-nés dans le monde entier. Clefting orofaciale est causée par 3 un développement anormal du visage. Chez l&#39;homme et la souris, la croissance initiale et structuration de la face repose sur plusieurs petits bourgeons de tissu pour le visage, les proéminences 4,5. Le visage est dérivée à partir de six protubérances frontales principales paires: les processus nasaux (FNP), les protubérances maxillaires (MXP) et des proéminences mandibulaires (MdP). Ces protubérances sont constitués de gonflements de mésenchyme qui sont enfermés dans un épithélium sus-jacent. Etudes de multiples espèces ont montré que la signalisation diaphonie entre ectoderme et le mésenchyme facial est essentiel pour façonner la face 6. Pourtant, les détails mécanistiques concernant les gènes impliqués dans ces relais de signalisation font défaut. Une façon d&#39;acquérir une compréhension globale de l&#39;expression des gènes, facteur de transcription liant, et les marques associées à la chromatine le déveectoderme ping visage et le mésenchyme est d&#39;isoler et de caractériser les différents types de tissus séparés. Nous présentons ici une méthode pour séparer l&#39;ectoderme facial et mésenchyme au jour embryonnaire (E) 10,5, une étape critique du développement de la formation de la souris pour le visage qui précède la fusion des protubérances. Notre méthode est une adaptation de l&#39;approche que nous avons utilisée précédemment pour disséquer les protubérances du visage 7. Dans cette étude, plus tôt nous avions utilisé C57BL consanguine / 6 souris que cette souche est devenu un standard pour la génétique, la morphologie du visage et de la génomique 8. Ici, cependant, en raison des quantités plus limitées de tissus disponibles, nous avons utilisé le consanguine souche CD-1 qui est moins cher à l&#39;achat, plus robuste pour l&#39;élevage, et qui tend à produire plus d&#39;embryons (12-18) par portée que n&#39;importe quel consanguine souche de souris 8. Suite à l&#39;isolation embryon, neutre protéase dispase II a été utilisé pour traiter l&#39;embryon entier. Ensuite, les protubérances faciales ont été disséquered dehors, et l&#39;ectoderme facial a été séparé du mésenchyme. Cette méthode permet de conserver à la fois l&#39;ectoderme facial et le mésenchyme intacte. Les échantillons obtenus selon cette méthode ne peut être utilisé pour des techniques telles que la détection de protéines, immunoprécipitation de la chromatine (ChIP) analyse, études de puces à ADN et l&#39;ARN-seq.

Après dispase II le traitement, l&#39;ectoderme de l&#39;embryon tend à être lâche. Les protubérances du visage doivent être intacts après dissection (figure 2A). L&#39;ectoderme isolé du visage est clair et exempt de tissu mésenchyme (figure 2B). Pour déterminer l&#39;efficacité du protocole et de détecter toute contamination croisée, nous dosés pour prosencéphale exprimé ZIC3 9, ectodermique spécifique CDH1 5 et mésenchymateuses spécifique SOX1...

Watch this Scientific Journal Video about Separation of Mouse Embryonic Facial Ectoderm and Mesenchyme at JoVE.com

Separation of Mouse Embryonic Facial Ectoderm and Mesenchyme

Un protocole pour la séparation de l&#39;ectoderme embryonnaire visage et le mésenchyme est décrite. Nous utilisons dispase II pour traiter les embryons entiers d&#39;abord, disséquer l&#39;ensemble du visage protubérances sur, puis séparer l&#39;ectoderme facial et le mésenchyme.

Séparation de souris embryonnaires ectoderme visage et Mesenchyme

 Orofacial clefts are the most frequent  craniofacial defects, which affect 1.5 in 1,000 newborns worldwide1,2. Orofacial clefting is caused by abnormal ...

separation-of-mouse-embryonic-facial-ectoderm-and-mesenchyme

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10.8K vues.  University of Colorado Denver Anschutz Medical Campus. Un protocole pour la séparation de l'ectoderme embryonnaire visage et le mésenchyme est décrite. Nous utilisons dispase II pour traiter les embryons entiers d'abord, disséquer l'ensemble du visage protubérances sur, puis séparer l'ectoderme facial et le mésenchyme.

Vidéo: Separation of Mouse Embryonic Facial Ectoderm and Mesenchyme

Electrophoretic Separation of Proteins

Electrophoresis is used to separate complex mixtures of proteins (e.g., from cells, subcellular fractions, column fractions, or immunoprecipitates), to investigate subunit compositions, and to verify homogeneity of protein samples. It can also serve to purify proteins for use in further applications. In polyacrylamide gel electrophoresis, proteins migrate in response to an electrical field through pores in a polyacrylamide gel matrix; pore size decreases with increasing acrylamide concentration. The combination of pore size and protein charge, size, and shape determines the migration rate of the protein. In this unit, the standard Laemmli method is described for discontinuous gel electrophoresis under denaturing conditions, i.e., in the presence of sodium dodecyl sulfate (SDS). 

In this video, we demonstrate a method for electrophoretic separation of proteins using poly-acrylimide gel electrophoresis (PAGE).

Séparation électrophorétique de protéines

Electrophoresis is used to separate complex mixtures of proteins (e.g., from cells, subcellular fractions, column fractions, or immunoprecipitates), to ...

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Biologie

Isolation and Derivation of Mouse Embryonic Germinal Cells

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum (dpc) mouse embryos.  Developing gonadal ridges from mouse embryos (C57BL6J) were dissociated by mechanical disruption with collagenase, then plated in a mouse embryo fibroblast feeder layer (MEF-CF1) that was previously mitotically inactivated with mitomycin C in the presence of knockout media and supplemented with Leukemia Inhibitor Factor (LIF), basic Fibroblast Growth Factor (bFGF), and Stem Cell Factor (SCF).  Using these optimized methods for PCG identification, isolation, and establishment of culture conditions permits long term cultures of EG cells for more than 40 days.  The embryonic germinal cell lines showed embryonic phenotype and expression of common used markers of the pluripotent state.  Isolation and derivation of germinal cells in culture provide a tool to understand their development in vitro and offer the opportunity to monitor cumulative damage at genetic and epigenetic levels after exposure to oxidative stress.

The ability of embryonic germinal cells to differentiate into primordial germinal cells during early development stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum mouse embryos.

L&#39;isolement et la dérivation de cellules germinales embryonnaires de souris

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental ...

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.

L&#39;imagerie in vivo et des traitements thérapeutiques dans un modèle de souris orthotopique de cancer des ovaires

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

Adenovirus-mediated Genetic Removal of Signaling Molecules in Cultured Primary Mouse Embryonic Fibroblasts

The ability to genetically remove specific components of various cell signalling cascades has been an integral tool in modern signal transduction analysis. One particular method to achieve this conditional deletion is via the use of the Cre-loxP system. This method involves flanking the gene of interest with loxP sites, which are specific recognition sequences for the Cre recombinase protein. Exposure of the so-called floxed (flanked by loxP site) DNA to this enzyme results in a Cre-mediated recombination event at the loxP sites, and subsequent excision of the intervening gene3. Several different methods exist to administer Cre recombinase to the site of interest. In this video, we demonstrate the use of an adenovirus containing the Cre recombinase gene to infect primary mouse embryonic fibroblasts (MEFs) obtained from embryos containing a floxed Rac1 allele1. Our rationale for selecting Rac1 MEFs for our experiments is that clear morphological changes can be seen upon deletion of Rac1, due to alterations in the actin cytoskeleton2,5. 72 hours following viral transduction and Cre expression, cells were stained using the actin dye phalloidin and imaged using confocal laser scanning microscopy. It was observed that MEFs which had been exposed to the adeno-Cre virus appeared contracted and elongated in morphology compared to uninfected cells, consistent with previous reports2,5. The adenovirus method of Cre recombinase delivery is advantageous as the adeno-Cre virus is easily available, and gene deletion via Cre in nearly 100% of the cells can be achieved with optimized adenoviral infection.

In this video we use an adenovirus carrying the Cre recombinase gene to infect primary mouse embryonic fibroblasts carrying a floxed Rac1 allele.

Adénovirus suppression génétique des molécules de signalisation dans les cultures de fibroblastes de souris embryonnaires primaires

The ability to genetically remove specific components of various cell signalling cascades has been an integral tool in modern signal transduction ...

Isolation and Culture of Cells from the Nephrogenic Zone of the Embryonic Mouse Kidney

Embryonic development of the kidney has been extensively studied both as a model for epithelial-mesenchymal interaction in organogenesis and to gain understanding of the origins of congenital kidney disease. More recently, the possibility of steering na&iuml;ve embryonic stem cells toward nephrogenic fates has been explored in the emerging field of regenerative medicine. Genetic studies in the mouse have identified several pathways required for kidney development, and a global catalog of gene transcription in the organ has recently been generated <a href="http://www.gudmap.org/">http://www.gudmap.org/</a>, providing numerous candidate regulators of essential developmental functions. Organogenesis of the rodent kidney can be studied in organ culture, and many reports have used this approach to analyze outcomes of either applying candidate proteins or knocking down the expression of candidate genes using siRNA or morpholinos. However, the applicability of organ culture to the study of signaling that regulates stem/progenitor cell differentiation versus renewal in the developing kidney is limited as cultured organs contain a compact extracellular matrix limiting diffusion of macromolecules and virus particles. To study the cell signaling events that influence the stem/progenitor cell niche in the kidney we have developed a primary cell system that establishes the nephrogenic zone or progenitor cell niche of the developing kidney ex vivo in isolation from the epithelial inducer of differentiation. Using limited enzymatic digestion, nephrogenic zone cells can be selectively liberated from developing kidneys at E17.5. Following filtration, these cells can be cultured as an irregular monolayer using optimized conditions. Marker gene analysis demonstrates that these cultures contain a distribution of cell types characteristic of the nephrogenic zone in vivo, and that they maintain appropriate marker gene expression during the culture period. These cells are highly accessible to small molecule and recombinant protein treatment, and importantly also to viral transduction, which greatly facilitates the study of candidate stem/progenitor cell regulator effects. Basic cell biological parameters such as proliferation and cell death as well as changes in expression of molecular markers characteristic of nephron stem/progenitor cells in vivo can be successfully used as experimental outcomes. Ongoing work in our laboratory using this novel primary cell technique aims to uncover basic mechanisms governing the regulation of self-renewal versus differentiation in nephron stem/progenitor cells.

In this report we describe a method for the isolation and culture of the progenitor cell niche from the embryonic mouse kidney that can be used to study signaling pathways regulating stem/progenitor cells of the developing kidney. These cultured cells are highly accessible to small molecule and recombinant protein treatment, and importantly also to viral transduction, which allows efficient manipulation of candidate pathways.

Isolement et culture de cellules de la zone néphrogénique du rein d&#39;embryon de souris

Embryonic development of the kidney has been extensively studied both as a model for epithelial-mesenchymal interaction in organogenesis and  to gain ...

Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling

Cell polarity is a fundamental property of eukaryotic cells that is dynamically regulated by both intrinsic and extrinsic factors during embryonic development 1, 2. One of the signaling pathways involved in this regulation is the Wnt pathway, which is used many times during embryogenesis and critical for human disease3, 4, 5. Multiple molecular components of this pathway coordinately regulate signaling in a spatially-restricted manner, but the underlying mechanisms are not fully understood. Xenopus embryonic epithelial cells is an excellent system to study subcellular localization of various signaling proteins. Fluorescent fusion proteins are expressed in Xenopus embryos by RNA microinjection, ectodermal explants are prepared and protein localization is evaluated by epifluorescence. In this experimental protocol we describe how subcellular localization of Diversin, a cytoplasmic protein that has been implicated in signaling and cell polarity determination6, 7 is visualized in Xenopus ectodermal cells to study Wnt signal transduction8. Coexpression of a Wnt ligand or a Frizzled receptor alters the distribution of Diversin fused with red fluorescent protein, RFP, and recruits it to the cell membrane in a polarized fashion 8, 9. This ex vivo protocol should be a useful addition to in vitro studies of cultured mammalian cells, in which spatial control of signaling differs from that of the intact tissue and is much more difficult to analyze.

Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling

Xenopus embryonic ectoderm has become an attractive model for studies of cell polarity. An assay is described, in which subcellular distribution of fluorescent proteins is assessed in ectoderm cells. This protocol will help address questions related to spatial control of signaling.

Translocation polarisée des protéines fluorescentes dans les Xenopus</emEctoderme> en réponse à la signalisation Wnt

Cell polarity is a fundamental property of eukaryotic cells that is dynamically regulated by both intrinsic and extrinsic factors during embryonic ...

Electroporation of Craniofacial Mesenchyme

Electroporation is an efficient method of delivering DNA and other charged macromolecules into tissues at precise time points and in precise locations. For example, electroporation has been used with great success to study neural and retinal development in Xenopus, chicken and mouse 1-10. However, it is important to note that in all of these studies, investigators were not targeting soft tissues. Because we are interested in craniofacial development, we adapted a method to target facial mesenchyme.
When we searched the literature, we found, to our surprise, very few reports of successful gene transfer into cartilaginous tissue. The majority of these studies were gene therapy studies, such as siRNA or protein delivery into chondrogenic cell lines, or, animal models of arthritis 11-13. In other systems, such as chicken or mouse, electroporation of facial mesenchyme has been challenging (personal communications, Dept of Craniofacial Development, KCL). We hypothesized that electroporation into procartilaginous and cartilaginous tissues in Xenopus might work better. In our studies, we show that gene transfer into the facial cartilages occurs efficiently at early stages (28), when the facial primordium is still comprised of soft tissue prior to cartilage differentiation.
Xenopus is a very accessible vertebrate system for analysis of craniofacial development. Craniofacial structures are more readily visible in Xenopus than in any other vertebrate model, primarily because Xenopus embryos are fertilized externally, allowing analyses of the earliest stages, and facilitating live imaging at single cell resolution, as well as reuse of the mothers 14. Among vertebrate models developing externally, Xenopus is more useful for craniofacial analysis than zebrafish, as Xenopus larvae are larger and easier to dissect, and the developing facial region is more accessible to imaging than the equivalent region in fish. In addition, Xenopus is evolutionarily closer to humans than zebrafish (&tilde;100 million years closer) 15. Finally, at these stages, Xenopus tadpoles are transparent, and concurrent expression of fluorescent proteins or molecules will allow easy visualization of the developing cartilages. We anticipate that this approach will allow us to rapidly and efficiently test candidate molecules in an in vivo model system.

Craniofacial cartilages develop in close contact with other tissues and are difficult to manipulate in live animals. We are using electroporation to deliver molecular tools during growth of the craniofacial skeleton while bypassing early embryonic effects. This approach will allow us to efficiently test candidate molecules in vivo.

Electroporation de Mesenchyme craniofaciale

Electroporation is an efficient method of delivering DNA and other charged macromolecules into tissues at precise time points and in precise locations. ...

Preparation of Mouse Embryonic Fibroblast Cells Suitable for Culturing Human Embryonic and Induced Pluripotent Stem Cells

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it is not easy to establish an effective system for culturing these cells. Since the culture conditions can influence gene expression that confers pluripotency in hESCs and hiPSCs, the optimization and standardization of the culture method is crucial.
The establishment of hESC lines was first described by using MEFs as feeder cells and fetal bovine serum (FBS)-containing culture medium2. Next, FBS was replaced with knockout serum replacement (KSR) and FGF2, which enhances proliferation of hESCs3. Finally, feeder-free culture systems enable culturing cells on Matrigel-coated plates in KSR-containing conditioned medium (medium conditioned by MEFs)4. Subsequently, hESCs culture conditions have moved towards feeder-free culture in chemically defined conditions5-7. Moreover, to avoid the potential contamination by pathogens and animal proteins culture methods using xeno-free components have been established8.
To obtain improved conditions mouse feeder cells have been replaced with human cell lines (e.g. fetal muscle and skin cells9, adult skin cells10, foreskin fibroblasts11-12, amniotic mesenchymal cells13). However, the efficiency of maintaining undifferentiated hESCs using human foreskin fibroblast-derived feeder layers is not as high as that from mouse feeder cells due to the lower level of secretion of Activin A14. Obviously, there is an evident difference in growth factor production by mouse and human feeder cells.
Analyses of the transcriptomes of mouse and human feeder cells revealed significant differences between supportive and non-supportive cells. Exogenous FGF2 is crucial for maintaining self-renewal of hESCs and hiPSCs, and has been identified as a key factor regulating the expression of Tgf&beta;1, Activin A and Gremlin (a BMP antagonist) in feeder cells. Activin A has been shown to induce the expression of OCT4, SOX2, and NANOG in hESCs15-16.
For long-term culture, hESCs and hiPSCs can be grown on mitotically inactivated MEFs or under feeder-free conditions in MEF-CM (MEF-Conditioned Medium) on Matrigel-coated plates to maintain their undifferentiated state. Success of both culture conditions fully depends on the quality of the feeder cells, since they directly affect the growth of hESCs.
Here, we present an optimized method for the isolation and culture of mouse embryonic fibroblasts (MEFs), preparation of conditioned medium (CM) and enzyme-linked immunosorbent assay (ELISA) to assess the levels of Activin A within the media.

The quality of mouse embryonic fibroblasts (MEFs) is dictated by the right strain of mouse such as CF-1. Pluripotency-supportive MEFs and conditioned media (CM) obtained from these should contain optimal concentrations of Activin A, Gremlin and Tgf&beta;1 needed for the Activin/Nodal and FGF pathways to co-operatively maintain self-renewal and pluripotency.

Préparation des cellules de souris embryonnaires fibroblastiques conviennent pour la culture embryonnaires humaines et cellules souches pluripotentes induites

In general, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs)1 can be cultured under variable conditions. However, it ...

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.

Un système d&#39;<em&gt; Ex vivo</emLa culture&gt; de pancréas embryonnaire

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

An Explant Assay for Assessing Cellular Behavior of the Cranial Mesenchyme

The central nervous system is derived from the neural plate that undergoes a series of complex morphogenetic movements resulting in formation of the neural tube in a process known as neurulation. During neurulation, morphogenesis of the mesenchyme that underlies the neural plate is believed to drive neural fold elevation. The cranial mesenchyme is comprised of the paraxial mesoderm and neural crest cells. The cells of the cranial mesenchyme form a pourous meshwork composed of stellate shaped cells and intermingling extracellular matrix (ECM) strands that support the neural folds. During neurulation, the cranial mesenchyme undergoes stereotypical rearrangements resulting in its expansion and these movements are believed to provide a driving force for neural fold elevation. However, the pathways and cellular behaviors that drive cranial mesenchyme morphogenesis remain poorly studied. Interactions between the ECM and the cells of the cranial mesenchyme underly these cell behaviors. Here we describe a simple ex vivo explant assay devised to characterize the behaviors of these cells. This assay is amendable to pharmacological manipulations to dissect the signaling pathways involved and live imaging analyses to further characterize the behavior of these cells. We present a representative experiment demonstrating the utility of this assay in characterizing the migratory properties of the cranial mesenchyme on a variety of ECM components.

The cranial mesenchyme undergoes dramatic morphogenic movements that likely provides a driving force for elevation of the neural folds1,2. Here we describe a simple ex vivo explant assay to characterize the cellular behaviors of the cranial mesenchyme during neurulation. This assay has numerous applications including being amenable to pharmacological manipulations and live imaging analyses.

Un test pour évaluer le comportement des explants cellulaires du mésenchyme crânienne

The central nervous system is derived from the neural plate that undergoes a series of complex morphogenetic movements resulting in formation of the ...