The author thanks Hugo Juraver-Geslin, Marion Wassef and Anne H&#233;l&#232;ne Monsoro-Burq for their help and advice, and the Animal Facility of the Institut Curie. The author thanks Paul Johnson for his editing work on the manuscript. This work was supported by the Centre National de la Recherche Scientifique (CNRS UMR8197, INSERM U1024) and by grants from the "Association pour la Recherche sur le Cancer" (ARC 4972 and ARC 5115; FRC DOC20120605233 and LABEX Memolife) and the Fondation Pierre Gilles de Gennes (FPGG0039).

<ol>
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The authors have nothing to disclose.

神経発生は（3,31,32に投稿）周囲の組織からの細胞の発生プログラムと信号間の複雑な相互作用によって編成されます。ここでは、Xで使用することができるプロトコルのセットを記述し外因性およびin vitroおよびin vivoでの神経運命の決意と神経形態形成に関与する内因性の要因を探るために胚をアフリカツメガエル 。これらのプロトコルは、Xでその?...

脊椎動物の神経系は神経上皮細胞の均質層として神経板から出てきます。発生プログラムは、神経板の地域化の際に、誘導された符号化され、確立されている方法を理解することは、現時点では、発生生物学の主要な目標です。他のシステムと比較して、実験的に影響を受けやすいアフリカツメガエル胚は神経発達1,2の初期段階を分析するための選択のモデルです。これは、胚を大量に得ることが容易であり、外部の開発は神経胚形成3の非常に最初のステップへのアクセスを提供します。多くのツールは、実験的にアフリカツメガエル （ アフリカツメガエル）胚発生を操作するために利用可能です。一緒に生化学的および薬理学的ツールで誘導MOを含めたmRNAまたはモルフォリノ（MO）のマイクロインジェクション、関数（GOF）および機能喪失（LOF）および経路4,5シグナリングの特定の改変の制御ゲインができます。 BLA胞胚の動物極の周りに配置stocoel屋根外胚葉、または非常に初期原腸胚、および「アニマルキャップ」（AC）とも呼ばれる前に遺伝子発現を操作することによってプログラムすることができる多能性細胞の供給源であります準備を外植片。この原稿ではXを使用するための詳細なプロトコルは、 ツメガエル交流植片は、in vitroおよびin vivo分子機構および細胞プロセス基盤となる神経の発達にテストします。 技術は、 アフリカツメガエルのオタマジャクシの神経管における遺伝子発現パターンの微細な観察 ​​を可能にする、運命の決意キューの同定における予備段階を提示しています。フラットマウント組織の観察は、一般にニワトリ胚6の研究で使用されるが、それは適切にアフリカツメガエルに記載されていません。 2または4細胞期胚の割球に合成mRNAまたはMOを注入することにより、遺伝子発現の操作は、ACのプログラミングを可能にします外植4。抗BMP要因ノギンの発現による骨形成タンパク質（BMP）経路の例を阻害するために、AC細胞3に神経アイデンティティを与えます。プロトコルは、陰イオン交換樹脂ビーズとの直接接触を介して、外因性の合図にAC外植片の局所及び露光時間制御を行うために詳述されています。最後に、技術は、解離および再会合プログラムの異なる細胞から調製した混合植片の移植により、インビボで神経前駆細胞の発達の機能をテストするために記載されています。 カエルの胚は、初期の脊椎動物の神経発達を研究するための強力なモデルです。 体外培養で外植片に遺伝子発現の操作を組み合わせることにより、神経上皮の地域化、増殖、および形態形成7-12の研究に重要な情報を提供しています。交流外植片のプログラミングは 、ex vivo 13,14の機能の心臓の開発を可能にしました。使用15を移植植片の神経堤分化プログラム16を誘導する最小の転写スイッチの同定につながりました。 透明帯境界のintrathalamica（ZLI）は尾側前脳の成長と地域化を制御するために、ソニックヘッジホッグ（Shhのを）分泌シグナルセンターです。連続のShhにさらされると、3転写因子の遺伝子を共発現神経上皮細胞- BARH様ホメオボックス2（barhl2）、orthodenticle-2（OTX2）とイロコイ-3（irx3 は） - ZLI室の二つの特徴を取得する：能力へSHH発現し、前方神経板の細胞から分離する能力。モデル系として、神経上皮細胞へのZLIの運命の誘導は8に提示されます。 これらのプロトコルは、基本的なMECを探索するために発達生物学者や他の研究者のための単純な、安く、効率的なツールを提供することを目指してキー神経細胞の挙動のhanisms。これらのプロトコルは、非常に汎用性であり、外因性および内因性神経決意合図の大規模な範囲の調査を可能にします。これは、神経系統のコミットメント、誘導性相互作用および細胞行動の生体分析に長期を可能にします。

<table><tbody><tr><td>Paraformaldehyde</td><td>VWR</td><td>&amp;nbsp;20909.290</td><td>Toxic</td></tr><tr><td>anion exchange resin beads</td><td>Biorad</td><td>140- 1231</td><td></td></tr><tr><td>Bovine Serum Albumin&amp;nbsp;</td><td>SIGMA</td><td>A-7888</td><td>For culture of animal cappH 7.6</td></tr><tr><td>Gentamycine&amp;nbsp;</td><td>GIBCO</td><td>15751-045&amp;nbsp;</td><td>antibiotic</td></tr><tr><td>Bovine Serum Albumin</td><td>SIGMA</td><td>A7906</td><td>&amp;nbsp;for bead preparation</td></tr></tbody></table>

stem cell-like xenopus embryonic explants to study early neural developmental features in vitro and in vivo

Understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. In the amphibian blastula, cells from the roof of the blastocoel are pluripotent. These cells can be isolated, and programmed to generate various tissues through manipulation of genes expression or induction by morphogens. In this manuscript protocols are described for the use of Xenopus laevis blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development. These protocols allow the investigation of fate acquisition, cell migration behaviors, and cell autonomous and non-autonomous properties. The blastocoel roof explants can be cultured in a serum-free defined medium and grafted into host embryos. This transplantation into an embryo allows the investigation of the long-term lineage commitment, the inductive properties, and the behavior of transplanted cells in vivo. These assays can be exploited to investigate molecular mechanisms, cellular processes and gene regulatory networks underlying neural development. In the context of regenerative medicine, these assays provide a means to generate neural-derived cell types in vitro that could be used in drug screening.

異なる種、発生学的操作、および調節遺伝子の発現パターンの形態学的考察に基づいて、概念モデルは、神経板が別個の組織原のフィールドを生成発達グリッドを定義し、横方向と縦方向のセグメントに分割されていることを保持しています。神経板では、前脳、中脳、後脳と脊髄の原基はすべて、すでに（23-25 ​​で検討）原腸陥入時に前後（AP）軸に沿っ...

Watch this Scientific Journal Video about Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo at JoVE.com

Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo

In Xenopus embryos, cells from the roof of the blastocoel are pluripotent and can be programmed to generate various tissues. Here, we describe protocols to use amphibian blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development.

幹細胞様<em&gt;アフリカツメガエル</em&gt;胚外植片を早期神経発達の特徴を研究するために<em&gt;インビトロ</em&gt;と<em&gt;インビボ</em

Understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. In the amphibian blastula, ...

stem-cell-like-xenopus-embryonic-explants-to-study-early-neural

Research

JoVE Journal

Developmental Biology

Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo

7.9K ビュー.  Institut Curie. In Xenopus embryos, cells from the roof of the blastocoel are pluripotent and can be programmed to generate various tissues. Here, we describe protocols to use amphibian blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development. 

ビデオ: Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo

Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus

Organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development. The Xenopuslaevis embryo is very useful for studying organogenesis because their large size makes them very suitable for identifying organs at the earliest steps in organogenesis. At this time, the primary method used for identifying a specific organ or primordium is whole mount in situ hybridization with labeled antisense RNA probes specific to a gene that is expressed in the organ of interest. In addition, it is relatively easy to manipulate genes or signaling pathways in Xenopus and in situ hybridization allows one to then assay for changes in the presence or morphology of a target organ. Whole mount in situ hybridization is a multi-day protocol with many steps involved. Here we provide a simplified protocol with reduced numbers of steps and reagents used that works well for routine assays. In situ hybridization robots have greatly facilitated the process and we detail how and when we utilize that technology in the process. Once an in situ hybridization is complete, capturing the best image of the result can be frustrating. We provide advice on how to optimize imaging of in situ hybridization results. Although the protocol describes assessing organogenesis in Xenopus laevis, the same basic protocol can almost certainly be adapted to Xenopus tropicalis and other model systems.

Understanding Early Organogenesis Using a Simplified In Situ Hybridization Protocol in Xenopus

The Xenopus laevis embryo continues to be exceptionally useful in the study of early development due to its large size and ease of manipulation. A simplified protocol for whole mount in situ hybridization protocol is provided that can be used in the identification of specific organs in this model system.

簡体字を使用した初期の器官形成の理解<em&gt;その場で</em&gt;ハイブリダイゼーションプロトコルで<em&gt;アフリカツメガエル</em

Organogenesis is the study of how organs are specified and then acquire their specific shape and functions during development.  The Xenopuslaevis embryo ...

発生生物学

Functional Cloning Using a Xenopus Oocyte Expression System

Identification of genes responsible for embryonic induction poses a number of challenges; to name a few, secreted molecules of interest may be low in abundance, may not be secreted but tethered to the signaling cell(s), or may require the presence of binding partners or upstream regulatory molecules. Thus in a search for gene products capable of eliciting an early lens-inductive response in competent ectoderm, we utilized an expression cloning system that would allow identification of paracrine or juxtacrine factors as well as transcriptional or other regulatory proteins. Pools of mRNA were injected into Xenopus oocytes, and responding tissue placed directly on the oocytes and co-cultured. Following functional cloning of ldb1 from a neural plate stage cDNA library based on its ability to elicit the expression of the early lens placode marker foxe3 in lens-competent animal cap ectoderm, we characterized the mRNA expression pattern, and assayed developmental progression following overexpression or knockdown of ldb1. This system is suitable in a very wide variety of contexts where identification of an inducer or its upstream regulatory molecules is sought using a functional response in competent tissue.

Functional Cloning Using a Xenopus Oocyte Expression System

We describe a Xenopus oocyte and animal cap system for the expression cloning of genes capable of inducing a response in competent ectoderm, and discuss techniques for the subsequent analysis of such genes. This system is useful in the functional identification of a wide range of gene products.

用いた機能クローニング<em&gt;アフリカツメガエル</em&gt;卵母細胞発現システム

Identification of genes responsible for embryonic induction poses a number of challenges; to name a few, secreted molecules of interest may be low in ...

Neural Explant Cultures from Xenopus laevis

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During axon outgrowth, the growth cone must integrate multiple sources of guidance cue information to modulate its cytoskeleton in order to propel the growth cone forward and accurately navigate to find its specific targets1. How this integration occurs at the cytoskeletal level is still emerging, and examination of cytoskeletal protein and effector dynamics within the growth cone can allow the elucidation of these mechanisms. Xenopus laevis growth cones are large enough (10-30 microns in diameter) to perform high-resolution live imaging of cytoskeletal dynamics (e.g.2-4 ) and are easy to isolate and manipulate in a lab setting compared to other vertebrates. The frog is a classic model system for developmental neurobiology studies, and important early insights into growth cone microtubule dynamics were initially found using this system5-7 . In this method8, eggs are collected and fertilized in vitro, injected with RNA encoding fluorescently tagged cytoskeletal fusion proteins or other constructs to manipulate gene expression, and then allowed to develop to the neural tube stage. Neural tubes are isolated by dissection and then are cultured, and growth cones on outgrowing neurites are imaged. In this article, we describe how to perform this method, the goal of which is to culture Xenopus laevis growth cones for subsequent high-resolution image analysis. While we provide the example of +TIP fusion protein EB1-GFP, this method can be applied to any number of proteins to elucidate their behaviors within the growth cone.

Neural Explant Cultures from Xenopus laevis

Culturing neural explants from dissected Xenopus laevis embryos that express fluorescent fusion proteins allows for imaging of growth cone cytoskeletal dynamics.

からの神経外植文化<em&gt;アフリカツメガエル</em

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During ...

神経科学

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and associated extracellular matrix. Because they provide a suitable organotypic environment, cortical slice explants are often used to investigate those interactions that control neuronal differentiation and development. Although beneficial, the slice explant model can suffer from drawbacks including aberrant cellular lamination and migration. Here we report a whole cerebral hemisphere explant system for studies of early cortical development that is easier to prepare than cortical slices and shows consistent organotypic migration and lamination. In this model system, early lamination and migration patterns proceed normally for a period of two days in vitro, including the period of preplate splitting, during which prospective cortical layer six forms. We then developed an ex utero electroporation (EUEP) approach that achieves ~80% success in targeting GFP expression to neurons developing in the dorsal medial cortex.
The whole hemisphere explant model makes early cortical development accessible for electroporation, pharmacological intervention and live imaging approaches. This method avoids the survival surgery required of in utero electroporation (IUEP) approaches while improving both transfection and areal targeting consistency. This method will facilitate experimental studies of neuronal proliferation, migration and differentiation.

Ex utero Electroporation and Whole Hemisphere Explants: A Simple Experimental Method for Studies of Early Cortical Development

This protocol describes an improved explant procedure that involves ex utero electroporation, dissection and culture of entire cerebral hemispheres from the embryonic mouse. The preparation facilitates pharmacological studies and assays of gene function during early cortical development.

exの子宮内エレクトロポレーションと全半球植：早期皮質の発達についての研究のための簡単な実験方法

Cortical development involves complex interactions between neurons and non-neuronal elements including precursor cells, blood vessels, meninges and ...

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological processes. In particular, appropriate regulation of calcium activity patterns during embryogenesis is necessary for many aspects of vertebrate neural development, including proper neural tube closure, synaptogenesis, and neurotransmitter phenotype specification. While the observation that calcium activity patterns can differ in both frequency and amplitude suggests a compelling mechanism by which these fluxes might transmit encoded signals to downstream effectors and regulate gene expression, existing population-level approaches have lacked the precision necessary to further explore this possibility. Furthermore, these approaches limit studies of the role of cell-cell interactions by precluding the ability to assay the state of neuronal determination in the absence of cell-cell contact. Therefore, we have established an experimental workflow that pairs time-lapse calcium imaging of dissociated neuronal explants with a fluorescence in situ hybridization assay, allowing the unambiguous correlation of calcium activity pattern with molecular phenotype on a single-cell level. We were successfully able to use this approach to distinguish and characterize specific calcium activity patterns associated with differentiating neural cells and neural progenitor cells, respectively; beyond this, however, the experimental framework described in this article could be readily adapted to investigate correlations between any time-series activity profile and expression of a gene or genes of interest.

Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis

We present a two-part protocol that combines fluorescent calcium imaging with in situ hybridization, allowing the experimenter to correlate patterns of calcium activity with gene expression profiles on a single-cell level.

ゼノプス・ラエビスにおける神経前駆体特性評価のための蛍光カルシウムイメージングとその後のその後の位置ハイブリダイゼーション

Spontaneous intracellular calcium activity can be observed in a variety of cell types and is proposed to play critical roles in a variety of physiological ...

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes in cell surface area and cell height, and where cells undergo mitosis and migrate. Furthermore, epithelial cells can also regulate morphogenetic movements in adjacent tissues1. A traditional method to study epithelial cells and tissues involve chemical fixation and histological methods to determine cell morphology or localization of particular proteins of interest. These approaches continue to be useful and provide "snapshots" of cell shapes and tissue architecture, however, much remains to be understood about how cells acquire specific shapes, how various proteins move or localize to specific positions, and what paths cells follow toward their final differentiated fate. High resolution live imaging complements traditional methods and also allows more direct investigation into the dynamic cellular processes involved in the formation, maintenance, and morphogenesis of multicellular epithelial sheets. Here we demonstrate experimental methods from the isolation of animal cap tissues from Xenopus laevis embryos to confocal imaging of epithelial cells and simple measurement approaches that together can augment molecular and cellular studies of epithelial morphogenesis.

Live-cell Imaging and Quantitative Analysis of Embryonic Epithelial Cells in Xenopus laevis

Xenopus embryonic epithelia are an ideal model system to study cell behaviors such as polarity development and shape change during epithelial morphogenesis. Traditional histology of fixed samples is increasingly being complemented by live-cell confocal imaging. Here we demonstrate methods to isolate frog tissues and visualize live epithelial cells and their cytoskeleton using live-cell confocal microscopy.

生細胞イメージングとの胚上皮細胞の定量分析アフリカツメガエル</em

Embryonic epithelial cells serve as an ideal model to study morphogenesis where multi-cellular tissues undergo changes in their geometry, such as changes ...

生物学

Generation of Na&#239;ve Blastoderm Explants from Zebrafish Embryos

Due to their optical clarity and rapid development, zebrafish embryos are an excellent system for examining cell behaviors and developmental processes. However, because of the complexity and redundancy of embryonic signals, it can be challenging to discern the complete role of any single signal during early embryogenesis. By explanting the animal region of the zebrafish blastoderm, relatively na&#239;ve clusters of embryonic cells are generated that can be easily cultured and manipulated ex vivo. By introducing a gene of interest by RNA injection before explantation, one can assess the effect of this molecule on gene expression, cell behaviors, and other developmental processes in relative isolation. Furthermore, cells from embryos of different genotypes or conditions can be combined in a single chimeric explant to examine cell/tissue interactions and tissue-specific gene functions. This article provides instructions for generating zebrafish blastoderm explants and demonstrates that a single signaling molecule - a Nodal ligand - is sufficient to induce germ layer formation and extension morphogenesis in otherwise na&#239;ve embryonic tissues. Due to their ability to recapitulate embryonic cell behaviors, morphogen gradients, and gene expression patterns in a simplified ex vivo system, these explants are anticipated to be of great utility to many zebrafish researchers.

Zebrafish blastoderm explants are generated by isolating embryonic cells from endogenous signaling centers within the early embryo, producing relatively na&#239;ve cell clusters easily manipulated and cultured ex vivo. This article provides instructions for making such explants and demonstrates their utility by interrogating roles for Nodal signaling during gastrulation.

ゼブラフィッシュ胚からのナイーブ・ブラストデム・エクスプラントの生成

Due to their optical clarity and rapid development, zebrafish embryos are an excellent system for examining cell behaviors and developmental processes. ...

Assessing Primary Neurogenesis in Xenopus Embryos Using Immunostaining

Primary neurogenesis is a dynamic and complex process during embryonic development that sets up the initial layout of the central nervous system. During this process, a portion of neural stem cells undergo differentiation and give rise to the first populations of differentiated primary neurons within the nascent central nervous system. Several vertebrate model organisms have been used to explore the mechanisms of neural cell fate specification, patterning, and differentiation. Among these is the African clawed frog, Xenopus, which provides a powerful system for investigating the molecular and cellular mechanisms responsible for primary neurogenesis due to its rapid and accessible development and ease of embryological and molecular manipulations. Here, we present a convenient and rapid method to observe the different populations of neuronal cells within Xenopus central nervous system. Using antibody staining and immunofluorescence on sections of Xenopus embryos, we are able to observe the locations of neural stem cells and differentiated primary neurons during primary neurogenesis.

Assessing Primary Neurogenesis in Xenopus Embryos Using Immunostaining

This article presents a convenient and rapid method for visualizing different neuronal cell populations in the central nervous system of Xenopus embryos using immunofluorescent staining on sections.

でプライマリ神経発生を評価します<em&gt;アフリカツメガエル</em&gt;胚用いた免疫染色

Primary neurogenesis is a dynamic and complex process during embryonic development that sets up the initial layout of the central nervous system. During ...

Blastomere Explants to Test for Cell Fate Commitment During Embryonic Development

Fate maps, constructed from lineage tracing all of the cells of an embryo, reveal which tissues descend from each cell of the embryo. Although fate maps are very useful for identifying the precursors of an organ and for elucidating the developmental path by which the descendant cells populate that organ in the normal embryo, they do not illustrate the full developmental potential of a precursor cell or identify the mechanisms by which its fate is determined. To test for cell fate commitment, one compares a cell's normal repertoire of descendants in the intact embryo (the fate map) with those expressed after an experimental manipulation. Is the cell's fate fixed (committed) regardless of the surrounding cellular environment, or is it influenced by external factors provided by its neighbors? Using the comprehensive fate maps of the Xenopus embryo, we describe how to identify, isolate and culture single cleavage stage precursors, called blastomeres. This approach allows one to assess whether these early cells are committed to the fate they acquire in their normal environment in the intact embryo, require interactions with their neighboring cells, or can be influenced to express alternate fates if exposed to other types of signals.

The fate of an individual embryonic cell can be influenced by inherited molecules and/or by signals from neighboring cells. Utilizing fate maps of the cleavage stage Xenopus embryo, single blastomeres can be identified for culture in isolation to assess the contributions of inherited molecules versus cell-cell interactions.

胚発生時に細胞運命のコミットメントをテストするために割球植

Fate maps, constructed from lineage tracing all of the cells of an embryo, reveal  which tissues descend from each cell of the embryo.  Although fate maps ...

Dissection of Xenopus laevis Neural Crest for in vitro Explant Culture or in vivo Transplantation

The neural crest (NC) is a transient dorsal neural tube cell population that undergoes an epithelium-to-mesenchyme transition (EMT) at the end of neurulation, migrates extensively towards various organs, and differentiates into many types of derivatives (neurons, glia, cartilage and bone, pigmented and endocrine cells). In this protocol, we describe how to dissect the premigratory cranial NC from Xenopus laevis embryos, in order to study NC development in vivo and in vitro. The frog model offers many advantages to study early development; abundant batches are available, embryos develop rapidly, in vivo gain and loss of function strategies allow manipulation of gene expression prior to NC dissection in donor and/or host embryos. The NC explants can be plated on fibronectin and used for in vitro studies. They can be cultured for several days in a serum-free defined medium. We also describe how to graft NC explants back into host embryos for studying NC migration and differentiation in vivo.

Dissection of Xenopus laevis Neural Crest for in vitro Explant Culture or in vivo Transplantation

This protocol describes how to dissect premigratory cranial neural crest (NC) from Xenopus laevis neurulas. These explants can be plated on fibronectin and cultured in vitro, or grafted back into host embryos. This technique allows studying the mechanisms of NC epithelium-to-mesenchyme transition, migration, and differentiation.

幹細胞様

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簡体字を使用した初期の器官形成の理解

用いた機能クローニング

からの神経外植文化

exの子宮内エレクトロポレーションと全半球植：早期皮質の発達についての研究のための簡単な実験方法

ゼノプス・ラエビスにおける神経前駆体特性評価のための蛍光カルシウムイメージングとその後のその後の位置ハイブリダイゼーション

生細胞イメージングとの胚上皮細胞の定量分析アフリカツメガエル

ゼブラフィッシュ胚からのナイーブ・ブラストデム・エクスプラントの生成

でプライマリ神経発生を評価します

胚発生時に細胞運命のコミットメントをテストするために割球植

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