Start-up verbas para A. Dickinson de VCU apoiaram este trabalho. Os autores gostariam de agradecer Dan Nacu por seu talento artístico na criação da ilustração esquemática.

<ol>
	<li>Mossey, P. A., Little, J., Munger, R. G., Dixon, M. J., Shaw, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cleft+lip+and+palate.">Cleft lip and palate.</a> Lancet. 374, 1773-1785 (2009).</li><li>Kennedy, A. E., Dickinson, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Median+facial+clefts+in+Xenopus+laevis:+roles+of+retinoic+acid+signaling+and+homeobox+genes.">Median facial clefts in Xenopus laevis: roles of retinoic acid signaling and homeobox genes.</a> Dev Biol. 365, 229-240 (2012).</li><li>Kennedy, A. E., Dickinson, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+Analysis+of+Orofacial+Development+and+Median+Clefts+in+Xenopus+Laevis.">Quantitative Analysis of Orofacial Development and Median Clefts in Xenopus Laevis.</a> Anat Rec (Hoboken). , (2014).</li><li>Dickinson, A., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positioning+the+extreme+anterior+in+Xenopus:+cement+gland,+primary+mouth+and+anterior+pituitary.">Positioning the extreme anterior in Xenopus: cement gland, primary mouth and anterior pituitary.</a> Semin Cell Dev Biol. 18, 525-533 (2007).</li><li>Dickinson, A. J., Sive, H. <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+primary+mouth+in+Xenopus+laevis.">Development of the primary mouth in Xenopus laevis.</a> Dev Biol. 295, 700-713 (2006).</li><li>Dickinson, A. J., Sive, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Wnt+antagonists+Frzb-1+and+Crescent+locally+regulate+basement+membrane+dissolution+in+the+developing+primary+mouth.">The Wnt antagonists Frzb-1 and Crescent locally regulate basement membrane dissolution in the developing primary mouth.</a> Development. 136, 1071-1081 (2009).</li><li>Barnett, 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=Syndrome+Transcription+Factor+is+critical+for+neural+crest+cell+function+in+Xenopus+laevis.">Syndrome Transcription Factor is critical for neural crest cell function in Xenopus laevis.</a> Mech Dev. 129, 324-338 (2012).</li><li>Gonzales, B., Yang, H., Henning, D., Valdez, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloning+and+functional+characterization+of+the+Xenopus+orthologue+of+the+Treacher+Collins+syndrome+(TCOF1)+gene+product.">Cloning and functional characterization of the Xenopus orthologue of the Treacher Collins syndrome (TCOF1) gene product.</a> Gene. 359, 73-80 (2005).</li><li>Reisoli, E., De Lucchini, S., Nardi, I., Ori, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serotonin+2B+receptor+signaling+is+required+for+craniofacial+morphogenesis+and+jaw+joint+formation+in+Xenopus.">Serotonin 2B receptor signaling is required for craniofacial morphogenesis and jaw joint formation in Xenopus.</a> Development. 137, 2927-2937 (2010).</li><li>Schuff, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FoxN3+is+required+for+craniofacial+and+eye+development+of+Xenopus+laevis.">FoxN3 is required for craniofacial and eye development of Xenopus laevis.</a> Dev Dyn. 236, 226-239 (2007).</li><li>Slater, B. J., Liu, K. J., Kwan, M. D., Quarto, N., Longaker, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cranial+osteogenesis+and+suture+morphology+in+Xenopus+laevis:+a+unique+model+system+for+studying+craniofacial+development.">Cranial osteogenesis and suture morphology in Xenopus laevis: a unique model system for studying craniofacial development.</a> PLoS One. 4, (2009).</li><li>Vandenberg, L. N., Adams, D. S., Levin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normalized+shape+and+location+of+perturbed+craniofacial+structures+in+the+Xenopus+tadpole+reveal+an+innate+ability+to+achieve+correct+morphology.">Normalized shape and location of perturbed craniofacial structures in the Xenopus tadpole reveal an innate ability to achieve correct morphology.</a> Dev Dyn. 241, 863-878 (2012).</li><li>Bugaighis, I., Mattick, C. R., Tiddeman, B., Hobson, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+Facial+Morphometry+in+Children+with+Oral+Clefts.">3D Facial Morphometry in Children with Oral Clefts.</a> Cleft Palate Craniofac J. , (2013).</li><li>Farkas, L. G., Katic, M. J., Forrest, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+anatomy+of+the+face+in+Down's+syndrome:+anthropometric+proportion+indices+in+the+craniofacial+regions.">Surface anatomy of the face in Down's syndrome: anthropometric proportion indices in the craniofacial regions.</a> J Craniofac Surg. 12, 519-524 (2001).</li><li>Scheuer, H. A., Holtje, W. J., Hasund, A., Pfeifer, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognosis+of+facial+growth+in+patients+with+unilateral+complete+clefts+of+the+lip,+alveolus+and+palate.">Prognosis of facial growth in patients with unilateral complete clefts of the lip, alveolus and palate.</a> J Craniomaxillofac Surg. 29, 198-204 (2001).</li><li>Parsons, K. J., Andreeva, V., James Cooper, W., Yelick, P. 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Os autores não têm nada a revelar.

Xenopus laevis tornou-se uma ferramenta útil para dissecar os mecanismos de desenvolvimento de desenvolvimento orofacial subjacente; no entanto, atualmente não há protocolos que descrevem tamanho e forma as mudanças desta região em sapos. O método aqui descrito vai contribuir significativamente para o campo do desenvolvimento orofacial, permitindo a quantificação mais rigorosa dos fenótipos orofaciais em Xenopus e outros vertebrados. O primeiro aspecto, mais críti...

Entre os tipos mais prevalentes e devastadores de defeitos congênitos humanos são aqueles que afetam a boca e face, tais como fendas orofaciais um. Crianças com estruturas orofaciais malformados passar por várias cirurgias ao longo da sua vida e luta com desfigurações faciais, voz, audição e problemas alimentares. Portanto, facilitando novas pesquisas no desenvolvimento crânio-orofacial e é fundamental para a prevenção e tratamento destes tipos de defeitos congênitos em humanos. Xenopus laevis surgiu como uma nova ferramenta para dissecar os mecanismos que regem o desenvolvimento craniofacial (alguns exemplos incluem 2,3,4 -11). Portanto, um método quantitativo para analisar tamanho e forma as mudanças durante o desenvolvimento da cabeça e do rosto desta espécie poderia ser muito poderosa 3. Aqui, apresentamos um método desse tipo; combinando medidas tradicionais de tamanho, com morfometria geométrica adaptados de um estudo Xenopus 12 </sup&gt; e uma riqueza de estudos que analisam forma facial humana 13-15. O objetivo deste protocolo é permitir que pesquisadores para quantificar o tamanho e formas facial para distinguir entre diferentes fenótipos orofaciais durante o desenvolvimento normal e anormal. Essa análise permitirá uma melhor diferenciação entre defeitos craniofaciais sutis, como os decorrentes de efeitos sinérgicos de genes e / ou fatores ambientais. Além disso, este método de quantificação também poderia revelar até mesmo ligeira melhoria ou resgate de um defeito orofacial. Este, portanto, faz com que seja um guia útil na análise de potenciais terapias. A combinação das medidas faciais e morfometria geométrica que apresentamos aqui permite uma análise estatística mais abrangente, tanto em tamanho e forma da região orofacial do que os protocolos actuais, que utilizam, em grande parte apenas um ou outro 15-18. Além disso, apresentamos uma forma simples de avaliar tanto a medial e planos laterais deo rosto sem a necessidade de equipamentos de imagem tridimensional sofisticado usado em estudos atuais 13,19. Demonstramos esse protocolo em Xenopus laevis embriões tratados com um inibidor do receptor do ácido retinóico que induz o desenvolvimento orofacial anormal e um 2,3 fenda palatina mediana. A quantificação das dimensões e forma da região orofacial nestes embriões revelou mudanças no terço médio da face, que é análogo aos seres humanos com fissuras palatinas semelhantes e modelos de mouse 20,21. No entanto, este protocolo pode ser utilizado para avaliar os efeitos de outros compostos no desenvolvimento orofacial substâncias naturais, tais como, herbicidas, ou proteínas, tais como factores de crescimento. Além disso, o tamanho e forma alterações orofaciais decorrentes de perturbação da expressão génica por via da perda ou ganho de experiências de função (utilizando morpholinos anti-sentido ou Crispers / Talens) pode também ser quantificada usando este protocolo. Por fim, desenvolvemos este método specificalmente para avaliar a morfologia de Xenopus; no entanto, é facilmente modificado para análise de qualquer vertebrado. Outras aplicações também poderia incluir o uso deste protocolo para a comparação de espécies estreitamente relacionadas para estudos evolutivos ou ecológicos. Embora o exemplo que fornecemos aqui utiliza este protocolo para descrever a análise da região orofacial, que poderia ser facilmente modificado para análise de outras regiões, órgãos ou estruturas. Este protocolo quantificação orofacial vai se tornar um recurso valioso para a comunidade de pesquisa, bem como uma excelente ferramenta de ensino para os alunos de graduação como uma demonstração em vídeo.

<table border="0" cellpadding="0" cellspacing="0" width="818">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">Name of the reagent</td>
			<td style="width:143px;">Company</td>
			<td style="width:136px;">Catalogue number</td>
			<td style="width:236px;">Comments (optional)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dissecting microscope</td>
			<td>Zeiss</td>
			<td></td>
			<td>fitted with AxioCamICC1 camera</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dumont #5 Inox forceps</td>
			<td>Fine Science Tools</td>
			<td>11251-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sterile, disposable scalpel</td>
			<td>Sklar</td>
			<td>06-2015</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">24-well plate</td>
			<td style="width:143px;">Fisher Scientific</td>
			<td style="width:136px;">087721</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:304px;">Standard Disposable transfer pipettes</td>
			<td style="width:143px;">Fisher Scientific</td>
			<td style="width:136px;">13-711-7M</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">150 mm X 15 mm Petri dishes</td>
			<td style="width:143px;">Falcon</td>
			<td style="width:136px;">351058</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Incubators</td>
			<td style="width:143px;">Ectotherm</td>
			<td style="width:136px;"></td>
			<td style="width:236px;">set to 15C or 20C&#160;</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:304px;">Modeling Clay</td>
			<td style="width:143px;">Premo, or other non-toxic modeling clay</td>
			<td style="width:136px;"></td>
			<td style="width:236px;">in black or white</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Straight teasing needle</td>
			<td style="width:143px;">Thermo Scientific</td>
			<td style="width:136px;">19010</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:304px;">Capillary Tubing (for needles)</td>
			<td>FHC</td>
			<td>30-30-1</td>
			<td style="width:236px;">Borosil 1.0mm OD x 0.5mm ID/Fiber, 100 mm each</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:304px;">Needle Puller, Model P-97&#160;</td>
			<td style="width:143px;">Sutter Instrument Co,&#160;</td>
			<td style="width:136px;">Needle Puller: P-97 Flaming/ Bown micropipette puller Filament: FB300B</td>
			<td style="width:236px;">For filaments, use Sutter 3.00mm square box filaments, 3.0mm wide.</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:304px;">Pipettemen</td>
			<td style="width:143px;">Gilson</td>
			<td style="width:136px;">F144802, F123600, F123602</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">BMS-453</td>
			<td style="width:143px;">Tocris</td>
			<td style="width:136px;">3409</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:304px;">DMSO</td>
			<td style="width:143px;">American Bioanalytical</td>
			<td style="width:136px;">AB00435-01000</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Cysteine</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:136px;">52-90-4</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">Paraformaldehyde powder</td>
			<td style="width:143px;">Sigma-Aldrich</td>
			<td style="width:136px;">158127</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:304px;">Petri dishes</td>
			<td style="width:143px;">Falcom</td>
			<td style="width:136px;">353003, 351058</td>
			<td style="width:236px;">100 mm diameter and 150 mm in diameter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:304px;">100% Ethanol</td>
			<td style="width:143px;">VWR</td>
			<td>89125-170</td>
			<td style="width:236px;"></td>
		</tr>
	</tbody>
</table>

quantification of orofacial phenotypes in xenopus

Xenopus tornou-se uma ferramenta importante para dissecar os mecanismos que regem o desenvolvimento craniofacial e defeitos. Um método para quantificar o desenvolvimento orofacial irá permitir uma análise mais rigorosa dos fenótipos orofaciais mediante revogação com substâncias que podem manipular geneticamente ou molecularmente a expressão do gene ou a função da proteína. Usando imagens bidimensionais dos chefes embrionárias, dimensões, tais como tamanho tradicional orofacial largura, altura e área- são medidos. Além disso, uma medida de arredondamento da abertura da boca embrionária é usada para descrever a forma da boca. Morfometria geométrica destes dois imagens tridimensionais também é executada para fornecer uma visão mais sofisticada de mudanças na forma da região orofacial. Marcos são atribuídos a pontos específicos na região orofacial e coordenadas são criados. A análise de componentes principais é usada para reduzir coordenadas marco para componentes principais que, em seguida, discriminam o tratamentogrupos. Estes resultados são exibidos como um gráfico de dispersão em que os indivíduos com formas orofaciais semelhantes se agrupam. Também é útil para executar uma análise da função discriminante, que compara estatisticamente as posições dos pontos de referência de entre dois grupos de tratamento. Esta análise é apresentada em uma grade transformação, onde mudanças na posição do marco são vistos como vetores. A grade é sobreposto a estes vetores para que um padrão de deformação é exibido para mostrar onde as posições marco significativas mudaram. As mudanças de forma na análise da função discriminante baseiam-se numa medida estatística, e, por conseguinte, pode ser avaliada por um valor de p. Esta análise é simples e acessível, necessitando apenas de um estereoscópio e software freeware, e, portanto, será um recurso valioso de pesquisa e ensino.

Aqui, foi demonstrada uma análise quantitativa do tamanho e forma orofacial para comparar os embriões tratados com um inibidor do receptor do ácido retinóico (RAR inibidor) a controlos não tratados. Os embriões foram tratados com uma concentração de 1 uM de inibidor químico esta fase de 24 a 30 anos (26-35 hpf), lavou-se para fora, e fixado em fase 42 (82 hpf). Eles foram, em seguida, processada e analisada como descrito no protocolo. Os resultados são dados originais, mas consistente com as observações em p...

Watch this Scientific Journal Video about Quantification of Orofacial Phenotypes in Xenopus at JoVE.com

Quantification of Orofacial Phenotypes in Xenopus

Um método para quantificar o tamanho e forma orofacial de embriões de Xenopus laevis foi desenvolvido. Neste protocolo, as medições de tamanho tradicional são combinados com morfometria geométrica para permitir análises mais sofisticadas de desenvolvimento orofacial e defeitos.

Quantificação de Orofacial nos fenótipos<em&gt; Xenopus</em

Xenopus has become an important tool for dissecting the mechanisms governing craniofacial development and defects. A method to quantify orofacial ...

quantification-of-orofacial-phenotypes-in-xenopus

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JoVE Journal

Biology

Quantification of Orofacial Phenotypes in Xenopus

9.7K visualizações.  Virginia Commonwealth University.  Um método para quantificar o tamanho e forma orofacial de embriões de Xenopus laevis foi desenvolvido. Neste protocolo, as medições de tamanho tradicional são combinados com morfometria geométrica para permitir análises mais sofisticadas de desenvolvimento orofacial e defeitos. 

Vídeo: Quantification of Orofacial Phenotypes in Xenopus

Microinjection of Xenopus Laevis Oocytes

Microinjection of Xenopus laevis oocytes followed by thin-sectioning electron microscopy (EM) is an excellent system for studying nucleocytoplasmic transport. Because of its large nucleus and high density of nuclear pore complexes (NPCs), nuclear transport can be easily visualized in the Xenopus oocyte. Much insight into the mechanisms of nuclear import and export has been gained through use of this system (reviewed by Pant&eacute;, 2006). In addition, we have used microinjection of Xenopus oocytes to dissect the nuclear import pathways of several viruses that replicate in the host nucleus. 
Here we demonstrate the cytoplasmic microinjection of Xenopus oocytes with a nuclear import substrate. We also show preparation of the injected oocytes for visualization by thin-sectioning EM, including dissection, dehydration, and embedding of the oocytes into an epoxy embedding resin. Finally, we provide representative results for oocytes that have been microinjected with the capsid of the baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV) or the parvovirus Minute Virus of Mice (MVM), and discuss potential applications of the technique.

Here we demonstrate cytoplasmic microinjection of Xenopus laevis oocytes with a nuclear import substrate, as well as preparation of the injected oocytes for visualization by thin-sectioning electron microscopy.

Microinjeção de Oócitos Xenopus laevis

Microinjection of Xenopus laevis oocytes followed by thin-sectioning electron microscopy (EM) is an excellent system for studying nucleocytoplasmic ...

Biologia

Visualizing RNA Localization in Xenopus Oocytes

RNA localization is a conserved mechanism of establishing cell polarity. Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to spatially restrict gene expression of Vg1 protein. Tight control of Vg1 distribution in this manner is required for proper germ layer specification in the developing embryo. RNA sequence elements in the 3' UTR of the mRNA, the Vg1 localization element (VLE) are required and sufficient to direct transport. To study the recognition and transport of Vg1 mRNA in vivo, we have developed an imaging technique that allows extensive analysis of trans-factor directed transport mechanisms via a simple visual readout. 
To visualize RNA localization, we synthesize fluorescently labeled VLE RNA and microinject this transcript into individual oocytes. After oocyte culture to allow transport of the injected RNA, oocytes are fixed and dehydrated prior to imaging by confocal microscopy. Visualization of mRNA localization patterns provides a readout for monitoring the complete pathway of RNA transport and for identifying roles in directing RNA transport for cis-acting elements within the transcript and trans-acting factors that bind to the VLE (Lewis et al., 2008, Messitt et al., 2008). We have extended this technique through co-localization with additional RNAs and proteins (Gagnon and Mowry, 2009, Messitt et al., 2008), and in combination with disruption of motor proteins and the cytoskeleton (Messitt et al., 2008) to probe mechanisms underlying mRNA localization.

Visualizing RNA Localization in Xenopus Oocytes

Visualization of in vivo RNA transport is accomplished by microinjection of fluorescently labeled RNA transcripts into Xenopus oocytes, followed by confocal microscopy.

Visualizando Localização RNA em Xenopus Oócitos

RNA localization is a conserved mechanism of establishing cell polarity.  Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to ...

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may also be used to study the structure-function relationship for other ion channels and neurotransmitter receptors1. BK channels are widely expressed in different tissues and have been implicated in many physiological functions, including regulation of smooth muscle contraction, frequency tuning of inner hair cells and regulation of neurotransmitter release2-6. BK channels are activated by membrane depolarization and by intracellular Ca2+ and Mg2+ 6-9. Therefore, the protocol is designed to control both the membrane voltage and the intracellular solution. In this protocol, messenger RNA of BK channels is injected into Xenopus laevis oocytes (stage V-VI) followed by 2-5 days of incubation at 18&deg;C10-13. Membrane patches that contain single or multiple BK channels are excised with the inside-out configuration using patch clamp techniques10-13. The intracellular side of the patch is perfused with desired solutions during recording so that the channel activation under different conditions can be examined. To summarize, the mRNA of BK channels is injected into Xenopus laevis oocytes to express channel proteins on the oocyte membrane; patch clamp techniques are used to record currents flowing through the channels under controlled voltage and intracellular solutions.

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

Ionic current of BK channels is recorded using patch clamp techniques. BK channels are expressed in Xenopus oocytes by injecting messenger RNA. The intracellular solution during patch clamp recordings is controlled by a perfusion system.

Grampo patch e Técnicas de Perfusão para estudar canais iônicos Expresso em Xenopus Oócitos

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may ...

RNAi Screening to Identify Postembryonic Phenotypes in C. elegans

C. elegans has proven to be a valuable model system for the discovery and functional characterization of many genes and gene pathways1. More sophisticated tools and resources for studies in this system are facilitating continued discovery of genes with more subtle phenotypes or roles. 
Here we present a generalized protocol we adapted for identifying C. elegans genes with postembryonic phenotypes of interest using RNAi2. This procedure is easily modified to assay the phenotype of choice, whether by light or fluorescence optics on a dissecting or compound microscope. This screening protocol capitalizes on the physical assets of the organism and molecular tools the C. elegans research community has produced. As an example, we demonstrate the use of an integrated transgene that expresses a fluorescent product in an RNAi screen to identify genes required for the normal localization of this product in late stage larvae and adults. First, we used a commercially available genomic RNAi library with full-length cDNA inserts. This library facilitates the rapid identification of multiple candidates by RNAi reduction of the candidate gene product. Second, we generated an integrated transgene that expresses our fluorecently tagged protein of interest in an RNAi-sensitive background. Third, by exposing hatched animals to RNAi, this screen permits identification of gene products that have a vital embryonic role that would otherwise mask a post-embryonic role in regulating the protein of interest. Lastly, this screen uses a compound microscope equipped for single cell resolution.

RNAi Screening to Identify Postembryonic Phenotypes in C. elegans

We describe a sensitized method to identify postembryonic regulators of protein expression and localization in C. elegans using an RNAi-based genomic screen and an integrated transgene that expresses a functional, fluorescently tagged protein.

RNAi de triagem para identificar fenótipos pós-embrionário em C. elegans</em

C. elegans has proven to be a valuable model system for the discovery and functional characterization of many genes and gene pathways1. More sophisticated ...

Facial Transplants in Xenopus laevis Embryos

Craniofacial birth defects occur in 1 out of every 700 live births, but etiology is rarely known due to limited understanding of craniofacial development. To identify where signaling pathways and tissues act during patterning of the developing face, a 'face transplant' technique has been developed in embryos of the frog Xenopus laevis. A region of presumptive facial tissue (the "Extreme Anterior Domain" (EAD)) is removed from a donor embryo at tailbud stage, and transplanted to a host embryo of the same stage, from which the equivalent region has been removed. This can be used to generate a chimeric face where the host or donor tissue has a loss or gain of function in a gene, and/or includes a lineage label. After healing, the outcome of development is monitored, and indicates roles of the signaling pathway within the donor or surrounding host tissues. Xenopus is a valuable model for face development, as the facial region is large and readily accessible for micromanipulation. Many embryos can be assayed, over a short time period since development occurs rapidly. Findings in the frog are relevant to human development, since craniofacial processes appear conserved between Xenopus and mammals.

Facial Transplants in Xenopus laevis Embryos

A technique for transplanting "Extreme Anterior Domain" facial tissue between Xenopus laevis embryos has been developed. Tissue can be moved from one gene expression background into another, allowing the study of local requirements for craniofacial development and for signaling interactions between facial regions.

Transplantes faciais em<em&gt; Xenopus laevis</em&gt; Os embriões

Craniofacial birth defects occur in 1 out of every 700 live births, but etiology is rarely known due to limited understanding of craniofacial development. ...

The Xenopus Oocyte Cut-open Vaseline Gap Voltage-clamp Technique With Fluorometry

The cut-open oocyte Vaseline gap (COVG) voltage clamp technique allows for analysis of electrophysiological and kinetic properties of heterologous ion channels in oocytes. Recordings from the cut-open setup are particularly useful for resolving low magnitude gating currents, rapid ionic current activation, and deactivation. The main benefits over the two-electrode voltage clamp (TEVC) technique include increased clamp speed, improved signal-to-noise ratio, and the ability to modulate the intracellular and extracellular milieu.
Here, we employ the human cardiac sodium channel (hNaV1.5), expressed in Xenopus oocytes, to demonstrate the cut-open setup and protocol as well as modifications that are required to add voltage clamp fluorometry capability.
The properties of fast activating ion channels, such as hNaV1.5, cannot be fully resolved near room temperature using TEVC, in which the entirety of the oocyte membrane is clamped, making voltage control difficult. However, in the cut-open technique, isolation of only a small portion of the cell membrane allows for the rapid clamping required to accurately record fast kinetics while preventing channel run-down associated with patch clamp techniques.
In conjunction with the COVG technique, ion channel kinetics and electrophysiological properties can be further assayed by using voltage clamp fluorometry, where protein motion is tracked via cysteine conjugation of extracellularly applied fluorophores, insertion of genetically encoded fluorescent proteins, or the incorporation of unnatural amino acids into the region of interest1. This additional data yields kinetic information about voltage-dependent conformational rearrangements of the protein via changes in the microenvironment surrounding the fluorescent molecule.

The Xenopus Oocyte Cut-open Vaseline Gap Voltage-clamp Technique With Fluorometry

The cut-open Vaseline gap approach is used to obtain low noise recordings of ionic and gating currents from voltage-dependent ion channels expressed in Xenopus oocytes with high resolution of fast channel kinetics. With minor modification, voltage clamp fluorometry can be coupled to the cut-open oocyte protocol.

O<em&gt; Xenopus</em&gt; Oocyte Cut-aberto vaselina Gap Técnica Voltage-clamp Com Fluorometria

The cut-open oocyte Vaseline gap (COVG) voltage clamp technique allows for analysis of electrophysiological and kinetic properties of heterologous ion ...

Reconstitution Of &#946;-catenin Degradation In Xenopus Egg Extract

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has been used to study protein turnover in many cellular contexts, including the cell cycle and signal transduction pathways1-3. Herein, a method is described for isolating Xenopus egg extract that has been optimized to promote the degradation of the critical Wnt pathway component, &beta;-catenin. Two different methods are described to assess &beta;-catenin protein degradation in Xenopus egg extract. One method is visually informative ([35S]-radiolabeled proteins), while the other is more readily scaled for high-throughput assays (firefly luciferase-tagged fusion proteins). The techniques described can be used to, but are not limited to, assess &beta;-catenin protein turnover and identify molecular components contributing to its turnover. Additionally, the ability to purify large volumes of homogenous Xenopus egg extract combined with the quantitative and facile readout of luciferase-tagged proteins allows this system to be easily adapted for high-throughput screening for modulators of &beta;-catenin degradation.

Reconstitution Of &amp;#946;-catenin Degradation In Xenopus Egg Extract

A method is described for analyzing protein degradation using radiolabeled and luciferase-fusion proteins in Xenopus egg extract and its adaptation for high-throughput screening for small molecule modulators of protein degradation.

Reconstituição de β-catenina degradação na<em&gt; Xenopus</em&gt; Extrato de ovo

Xenopus laevis egg extract is a well-characterized, robust system for studying the biochemistry of diverse cellular processes. Xenopus egg extract has ...

Perfusão sanguínea em rãs africanas com garras para transcriptômica e proteômica

Effective Rapid Blood Perfusion in Xenopus

Xenopus have been powerful model organisms for understanding vertebrate development and disease for over 100 years. Here, a rapid blood perfusion protocol in Xenopus, aimed at a consistent and drastic reduction of blood within all tissues, is defined. Perfusion is carried out by inserting a needle directly into the ventricle of the heart and pumping heparinized phosphate-buffered saline (PBS) through the vascular system. The procedure can be completed in approximately 10 min per animal. The blood is dominated by a few highly abundant proteins and cell types, creating numerous issues as these proteins mask most other molecules and cell types of interest. The reproducible characterization of adult Xenopus tissues with quantitative proteomics and single-cell transcriptomics will benefit from applying this protocol prior to organ sampling. The protocols for tissue sampling are defined in companion papers. These procedures are aimed at the standardization of practices across Xenopus of different sex, age, and health status, specifically X. laevis and X. tropicalis.

Autor em destaque: Perfusão sanguínea rápida e eficaz em Xenopus  

Presented here is an effective rapid blood perfusion protocol to prepare tissue samples from African clawed frogs for transcriptomics and proteomics studies.

Perfusão sanguínea rápida eficaz em Xenopus

Xenopus have been powerful model organisms for understanding vertebrate development and disease for over 100 years. Here, a rapid blood perfusion protocol ...