这个工作是由一个BBSRC授予环保部（BB / H010297 / 1），一个BBSRC助学金名额特区，以及MRC助学金为SWF。

<ol>
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The authors have no competing financial interests.

此协议的一个重要部分是产生了通常处理的，分泌的，并能够引发所述接收单元在响应中，尽管具有连接荧光部分生物活性配体。关键是要建立的荧光标记的基因产物是生物学活性使用适当的测定法。为的Shh-GFP，以激活PTC1的表达的能力，确认16。 Wnt8a具有显着有效的能力以诱导次级轴时在单个卵裂球腹20-21表达，Wnt8a-HA-eGFP的显示出保留这种生物活性。 Wnt11b抑制活化处理外?...

在早期胚胎发育，细胞被逐步致力于遵循分化的特定谱系：这意味着一组全能性（或多潜能）细胞变得逐渐限制到建立确定为产生一种细胞类型的祖细胞群体的。细胞 - 细胞信号传导是至关重要的谱系说明书的胚胎发育过程中的调节。这些信号的操作将被要求直接干细胞向特定的命运，以支持新的医疗方法。 相当一小部分的信号通路的发展过程中重申，包括路径响应TGF超家族（nodals和骨形成蛋白）1-2的FGFs 3，Wnts 4，和刺猬5。这些分泌的蛋白质结合存在于细胞膜，激活的信号转导，从而改变基因的表达和/或细胞行为受体。细胞标志的严格监管阿灵是细胞谱系的规范和正常发展的必要条件。而这些通路中的串扰是在确定细胞命运的重要，一个单一的配位体可以本身引起不同浓度不同的反应。形态发生素梯度被描述在100多年前作为一个理论来解释如何不同类型的细胞可以从细胞中6场获得。信令由一个小区组产生的分子可以扩散在一定范围内，减少在浓度与来自源更大的距离。暴露于信号的细胞将响应的局部浓度在其在电池领域位置，与细胞在不同的位置响应不同，以不同的水平的信号。用于形态发生素的存在的证据来自早期果蝇胚胎7和翼盘 8，以及脊椎动物肢9和神经管10的研究。 方法都需要在vestigate怎么形​​态发生素梯度成立，并确定在调节这些梯度其他重要分子。使用免疫组织化学来可视化内源性蛋白在体内的不同遗传背景的上下文优雅实验已经用于研究形态发生素梯度11-12然而，好的抗体和特定的突变体不总是可用的，所以我们在这里描述使用爪蟾荧光配体的过表达，是提供一种替代方案中，简单的方法来剖析外源基因产物如何影响跨越细胞的场配位体的分布的协议。 非洲爪蟾提供了一个很好的系统，其胚胎外部发展，使他们在最初阶段访问承接这些类型的实验。他们的大尺寸（直径1-1.5mm）简化了显微注射和手术操作和囊胚阶段的细胞很容易的图像，因为它们仍然是比较大的（约2081，M对面）。在爪蟾表达研究是简单的事：基因注入胚胎早期可以有针对性的特殊细胞，并有效地翻译。 使用PCS2 Wnt8a-HA 13，PCS2 Wnt11b-HA 14和绿色荧光蛋白生成的荧光标记Wnt8a / Wnt11b-HA-EGFP结构。的HA肽是重要的，包括，不仅提供额外的分子标记，而且还因为它被认为是作为一个隔离物分离的Wnt和eGFP的蛋白质允许两个基因产物的功能。用于Shh的可视化的构建体是以前用于产生转基因小鼠表达的Shh-EGFP融合蛋白15;这是好心由安迪·麦克马洪提供。重要的是，对于所有的构建体的GFP标签克隆的3&#39;到信号序列，这样它被处理后保留。它也必须确保最终蛋白质包括所需的修饰序列，例如所述additioÑ​​脂质作为是亚克隆到被合成mRNA的脾淋巴细胞优化PCS2 +表达载体Shh和Wnt信号ligands.The的cDNA的情况下它包含一个SP6启动子和多聚腺苷酸化信号（http://sitemaker.umich.edu/dlturner.vectors）。 这里介绍的工作提供了一个简单的协议，用于比较的分泌和荧光扩散标记的Wnt和Shh标记的配体。通过注入合成的mRNA的确定量，协议会绕开可变表达使用不同启动子的不同向量有关的任何问题。这些方法最近已应用到调查硫酸乙酰肝素endosulfatase Sulf1上的Shh-EGFP和Wnt8a / Wnt11b-HA-eGFP的分泌和扩散在爪蟾16-17的影响。

<table>
	<tbody>
		<tr>
			<td>Agarose</td>
			<td>Melford</td>
			<td>MB 1200</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium acetate</td>
			<td>Ambion</td>
			<td>From Megascript SP6 Kit AM 1330</td>
			<td></td>
		</tr>
		<tr>
			<td>Bicarbonate</td>
			<td>VWR International</td>
			<td>RC-091</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium nitrate</td>
			<td>Sigma</td>
			<td>C13961</td>
			<td></td>
		</tr>
		<tr>
			<td>Cap analog (m7G(5&#39;))</td>
			<td>Applied Biosystems</td>
			<td>AM 8050</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Sigma</td>
			<td>C 2432</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;L-Cysteine hydrochloride monohydrate</td>
			<td>Sigma</td>
			<td>C7880</td>
			<td></td>
		</tr>
		<tr>
			<td>dNTPs</td>
			<td>Invitrogen</td>
			<td>18427-013</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid (EDTA)</td>
			<td>Sigma</td>
			<td>O3690</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>VWR International</td>
			<td>20821.33</td>
			<td></td>
		</tr>
		<tr>
			<td>Ficoll 400</td>
			<td>Sigma</td>
			<td>F 4375</td>
			<td></td>
		</tr>
		<tr>
			<td>Fiji image J software</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Free download http://fiji.sc/Fiji</td>
		</tr>
		<tr>
			<td>Gentamycin</td>
			<td>Melford</td>
			<td>G 0124</td>
			<td></td>
		</tr>
		<tr>
			<td>Glacial acetic acid</td>
			<td>Fisher Scientific</td>
			<td>A/0400/PB17</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass cover slips, No.1.5&#160;</td>
			<td>Scientific Laboratory Supplies</td>
			<td>22X22-SGJ3015. 22X50-SGJ3030&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass needle puller</td>
			<td>Narishige</td>
			<td>Narishige PC -10</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass pull needles</td>
			<td>Drummond Scientific</td>
			<td>3-000-203-G/X</td>
			<td></td>
		</tr>
		<tr>
			<td>Human chronic gonadotropin (HCG)</td>
			<td>Intervet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Fisher Scientific</td>
			<td>P/7500/PB17</td>
			<td></td>
		</tr>
		<tr>
			<td>Lithium chloride (LiCl)</td>
			<td>Sigma</td>
			<td>L-7026</td>
			<td></td>
		</tr>
		<tr>
			<td>LSM710 and Zen software (2008-2010)</td>
			<td>Carl Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matlab software</td>
			<td>Mathworks</td>
			<td></td>
			<td>http://uk.mathworks.com/</td>
		</tr>
		<tr>
			<td>Molecular grade water&#160;</td>
			<td>Fisher Scientific</td>
			<td>BP 2819-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Nail varnish&#160;</td>
			<td>Boots</td>
			<td>Bar code 3600530 373048</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer</td>
			<td>Lab.tech International</td>
			<td>ND-1000 / ND8000</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish (55mm)</td>
			<td>VWR International</td>
			<td>391-0865</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenol-chloroform</td>
			<td>Sigma</td>
			<td>P3803</td>
			<td></td>
		</tr>
		<tr>
			<td>Photoshop software</td>
			<td>Adobe</td>
			<td>N/A</td>
			<td>http://www.photoshop.com/products</td>
		</tr>
		<tr>
			<td>High fidelity DNA polymerase and buffers&#160;</td>
			<td>Biolabs</td>
			<td>M0530S&#160; Buffer - M0531S</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride (KCl)</td>
			<td>Fisher Scientific</td>
			<td>P/4280/53</td>
			<td></td>
		</tr>
		<tr>
			<td>PVC insulation tape</td>
			<td>Onecall</td>
			<td>SH5006MPK</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel extraction kit&#160;</td>
			<td>Qiagen</td>
			<td>S28704</td>
			<td></td>
		</tr>
		<tr>
			<td>Restriction enzymes buffers</td>
			<td>Roche</td>
			<td colspan="2">SuRE/CUT Buffer Set 11082 035 001</td>
		</tr>
		<tr>
			<td>RNAse-free DNAse</td>
			<td>Promega</td>
			<td>ME10A</td>
			<td></td>
		</tr>
		<tr>
			<td>Steel back single edge blades</td>
			<td>Personna</td>
			<td>66-0403-0000</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride (NaCl)</td>
			<td>Fisher Scientific</td>
			<td>27810.364</td>
			<td></td>
		</tr>
		<tr>
			<td>SP6 transcription kit</td>
			<td>Ambion</td>
			<td>AM1330</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass slides</td>
			<td>Thermo Fisher</td>
			<td>SHE 2505</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris base</td>
			<td>Invitrogen</td>
			<td>15504-020</td>
			<td></td>
		</tr>
		<tr>
			<td>Tungsten needles</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>homemade</td>
		</tr>
		<tr>
			<td>Zen lite software</td>
			<td>Carl Zeiss</td>
			<td>N/A</td>
			<td>Free download&#160; http://www.zeiss.co.uk/microscopy/en_gb/downloads/zen.html</td>
		</tr>
	</tbody>
</table>

using confocal analysis of xenopus laevis to investigate modulators of wnt and shh morphogen gradients

这个协议描述了一种方法来可视化分布在细胞的场配位体。表达外源蛋白，用自己的细胞在早期胚胎中大尺寸在一起的易用性，使 非洲爪蟾 的可视化GFP标记的配体的一个有用的模型。的合成mRNAs注射后能有效地转化为早期爪 蟾胚胎 ，和注射剂可以针对单个小区。当与谱系示踪剂组合如膜拴RFP，注入的细胞（和它的后代）所产生的过表达的蛋白质可以容易地遵循。这个协议描述了生产的方法的荧光从注入的mRNA标记的Wnt和Shh配体。该方法涉及英里CRO清扫外胚层植（动物帽）和配体扩散的多个样品中分析。通过使用共焦成像，可以获得关于配体分泌和扩散过的细胞的字段信息。共焦图象的统计分析提供关于配体梯度的形状的量化数据。这些方法可能是有用的研究人员谁想要测试的可能调节形态发生梯度的形状因素的影响。

动物帽外植体共聚焦分析表达荧光标记的蛋白质提供了一个有效的系统来可视化不同的实验条件下配体的分布。在一个实例中，绿色荧光蛋白的分布标记的Shh所示（ 图1）。在2-细胞阶段， 爪蟾胚胎注入到两个小区中可以包含一个控制mRNA或mRNA的编码Sulf1，修饰细胞表面硫酸乙酰肝素和影响的Shh形态发生梯度16的酶。这些胚胎进行培养直到32细胞阶段和单细胞是共注射用?...

Watch this Scientific Journal Video about Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients at JoVE.com

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

该手稿这里提供一组简单的用于分析的在爪蟾荧光标记的配体的分泌和扩散的方法。这提供了一个上下文用于测试的其他蛋白质的修改配体分布的能力，并允许实验，可能会给洞察调节形态发生素梯度的机制。

利用共聚焦分析<em&gt;非洲爪蟾</em&gt;调查的Wnt和Shh形态发生素梯度的调节剂

This protocol describes a method to visualise ligands distributed across a field of cells. The ease of expressing exogenous proteins, together with the ...

using-confocal-analysis-xenopus-laevis-to-investigate-modulators-wnt

Research

JoVE Journal

Developmental Biology

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

11.0K 次观看.  The Bateson Centre, University of Sheffield.  该手稿这里提供一组简单的用于分析的在爪蟾荧光标记的配体的分泌和扩散的方法。这提供了一个上下文用于测试的其他蛋白质的修改配体分布的能力，并允许实验，可能会给洞察调节形态发生素梯度的机制。 

视频: Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

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.

了解早期器官使用简体<em&gt;原位</em&gt;杂交协议<em&gt;爪</em

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

科研

发育生物学

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during oogenesis. In order to study roles of such maternal factors in early embryonic development, it is desirable to manipulate their functions from the very beginning of embryonic development. Conventional ways of gene interference are achieved by injection of antisense oligonucleotides (oligos) or mRNA into fertilized eggs, enabling under- or over-expression of specific proteins, respectively. However, these methods normally require more than several hours until protein expression is affected, and, hence, the interference of gene functions is not effective during early embryonic stages. Here, we introduce an experimental system in which expression levels of maternal proteins can be altered before fertilization. Xenopus laevis oocytes obtained from ovaries are defolliculated by incubating with enzymes. Antisense oligos or mRNAs are injected into defolliculated oocytes at the germinal vesicle (GV) stage. These oocytes are in vitro matured to eggs at the metaphase II (MII) stage, followed by intracytoplasmic sperm injection (ICSI). By this way, up to 10% of ICSI embryos can reach the swimming tadpole stage, thus allowing functional tests of specific gene knockdown or overexpression. This approach can be a useful way to study roles of maternally stored factors in early embryonic development.

Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development

We describe methods of manipulating Xenopus laevis immature oocytes, in vitro maturation of oocytes to eggs, and intracytoplasmic sperm injection. This protocol allows degradation of some maternal proteins and overexpression of genes of interest at fertilization, and hence is valuable to study roles of specific factors in early embryonic development.

操作和<em&gt;在体外</em中&gt;成熟<em&gt;非洲爪蟾</em&gt;卵母细胞，其次是胞浆内单精子注射，研究胚胎发育

Amphibian eggs have been widely used to study embryonic development. Early embryonic development is driven by maternally stored factors accumulated during ...

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.

功能性克隆使用<em&gt;爪</em&gt;卵母细胞表达系统

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

Loss- and Gain-of-function Approach to Investigate Early Cell Fate Determinants in Preimplantation Mouse Embryos

Gene silencing and overexpression techniques are instrumental for the identification of genes involved in embryonic development. Direct target gene modification in preimplantation embryos provides a means to study the underlying mechanisms of genes implicated in, for instance, cellular differentiation into the trophectoderm (TE) and the inner cell mass (ICM). Here, we describe a protocol that examines the role of neogenin as an authentic receptor for initial cell fate determination in preimplantation mouse embryos. First, we discuss the experimental manipulations that were used to produce gain and loss of neogenin function by microinjecting neogenin cDNA and shRNA; the effectiveness of this approach was confirmed by a strong correlation between the pair-wise expression levels of either red fluorescent protein (RFP) or green fluorescent protein (GFP) and the immunocytochemical quantification of neogenin expression. Secondly, overexpression of neogenin in preimplantation mouse embryos leads to normal ICM development while neogenin knockdown causes the ICM to develop abnormally, implying that neogenin could be a receptor that relays extracellular cues to drive blastomeres to early cell fates. Given the success of this detailed protocol in investigating the function of a novel embryonic developmental stage-specific receptor, we propose that it has the potential to aid in exploration and identification of other stage-specific genes during embryogenesis.

The goal of this protocol is to describe a loss- and gain-of function method that is applicable to identify neogenin as a stage-specific receptor that leads to trophectoderm and inner cell mass differentiation in preimplantation mouse embryos.

损失 - 和增益的功能角度进行调查研究早期细胞命运决定在植入前小鼠胚胎

 Gene silencing and overexpression techniques are instrumental for the identification of genes involved in embryonic development. Direct target gene ...

Technique to Target Microinjection to the Developing Xenopus Kidney

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus embryos are large, develop externally, and can be easily manipulated by microinjection or surgical procedures. In addition, fate maps have been established for early Xenopus embryos. Targeted microinjection into the individual blastomere that will eventually give rise to an organ or tissue of interest can be used to selectively overexpress or knock down gene expression within this restricted region, decreasing secondary effects in the rest of the developing embryo. In this protocol, we describe how to utilize established Xenopus fate maps to target the developing Xenopus kidney (the pronephros), through microinjection into specific blastomere of 4- and 8-cell embryos. Injection of lineage tracers allows verification of the specific targeting of the injection. After embryos have developed to stage 38 - 40, whole-mount immunostaining is used to visualize pronephric development, and the contribution by targeted cells to the pronephros can be assessed. The same technique can be adapted to target other tissue types in addition to the pronephros.

Technique to Target Microinjection to the Developing Xenopus Kidney

Here, we present a protocol to use fate maps and lineage tracers to target injections into individual blastomeres that give rise to the kidney of Xenopus laevis embryos.

技术目标显微注射到显影<em&gt;爪</em&gt;肾

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus ...

Studying Wnt Signaling During Patterning of Conducting Airways

Wnt signaling pathways play critical roles during development of the respiratory tract. Defining precise mechanisms of differentiation and morphogenesis controlled by Wnt signaling is required to understand how tissues are patterned during normal development. This knowledge is also critical to determine the etiology of birth defects such as lung hypoplasia and tracheobronchomalacia. Analysis of earliest stages of development of respiratory tract imposes challenges, as the limited amount of tissue prevents the performance of standard protocols better suited for postnatal studies. In this paper, we discuss methodologies to study cell differentiation and proliferation in the respiratory tract. We describe techniques such as whole mount staining, processing of the tissue for confocal microscopy and immunofluorescence in paraffin sections applied to developing tracheal lung. We also discuss methodologies for the study of tracheal mesenchyme differentiation, in particular cartilage formation. Approaches and techniques discussed in the current paper circumvent the limitation of material while working with embryonic tissue, allowing for a better understanding of the patterning process of developing conducting airways.

The use of reporter mice coupled to whole mount and section staining, microscopy and in vivo assays facilitates the analysis of mechanisms underlying the normal patterning of the respiratory tract. Here we describe how these techniques contributed to the analysis of Wnt signaling during tracheal development.

研究Wnt信号传导过程中的航空公司图案

Wnt signaling pathways play critical roles during development of the respiratory tract. Defining precise mechanisms of differentiation and morphogenesis ...

Building Finite Element Models to Investigate Zebrafish Jaw Biomechanics

Skeletal morphogenesis occurs through tightly regulated cell behaviors during development; many cell types alter their behavior in response to mechanical strain. Skeletal joints are subjected to dynamic mechanical loading. Finite element analysis (FEA) is a computational method, frequently used in engineering that can predict how a material or structure will respond to mechanical input. By dividing a whole system (in this case the zebrafish jaw skeleton) into a mesh of smaller 'finite elements', FEA can be used to calculate the mechanical response of the structure to external loads. The results can be visualized in many ways including as a 'heat map' showing the position of maximum and minimum principal strains (a positive principal strain indicates tension while a negative indicates compression. The maximum and minimum refer the largest and smallest strain). These can be used to identify which regions of the jaw and therefore which cells are likely to be under particularly high tensional or compressional loads during jaw movement and can therefore be used to identify relationships between mechanical strain and cell behavior. This protocol describes the steps to generate Finite Element models from confocal image data on the musculoskeletal system, using the zebrafish lower jaw as a practical example. The protocol leads the reader through a series of steps: 1) staining of the musculoskeletal components, 2) imaging the musculoskeletal components, 3) building a 3 dimensional (3D) surface, 4) generating a mesh of Finite Elements, 5) solving the FEA and finally 6) validating the results by comparison to real displacements seen in movements of the fish jaw.

Finite Element Analysis is a frequently used tool to investigate the mechanical performance of structures under load. Here we apply its use to modeling the biomechanics of the zebrafish jaw.

建立有限元模型，研究斑马鱼下颌生物力学

Skeletal morphogenesis occurs through tightly regulated cell behaviors during development; many cell types alter their behavior in response to mechanical ...

Visualization and Quantitative Analysis of Embryonic Angiogenesis in Xenopus tropicalis

Blood vessels supply oxygen and nutrients throughout the body, and the formation of the vascular network is under tight developmental control. The efficient in vivo visualization of blood vessels and the reliable quantification of their complexity are key to understanding the biology and disease of the vascular network. Here, we provide a detailed method to visualize blood vessels with a commercially available fluorescent dye, human plasma acetylated low density lipoprotein DiI complex (DiI-AcLDL), and to quantify their complexity in Xenopus tropicalis. Blood vessels can be labeled by a simple injection of DiI-AcLDL into the beating heart of an embryo, and blood vessels in the entire embryo can be imaged in live or fixed embryos. Combined with gene perturbation by the targeted microinjection of nucleic acids and/or the bath application of pharmacological reagents, the roles of a gene or of a signaling pathway on vascular development can be investigated within one week without resorting to sophisticated genetically engineered animals. Because of the well-defined venous system of Xenopus and its stereotypic angiogenesis, the sprouting of pre-existing vessels, vessel complexity can be quantified efficiently after perturbation experiments. This relatively simple protocol should serve as an easily accessible tool in diverse fields of cardiovascular research.

Visualization and Quantitative Analysis of Embryonic Angiogenesis in Xenopus tropicalis

This protocol demonstrates a fluorescence-based method to visualize the vasculature and to quantify its complexity in Xenopus tropicalis. Blood vessels can be imaged minutes after the injection of a fluorescent dye into the beating heart of an embryo after genetic and/or pharmacological manipulations to study cardiovascular development in vivo.

胚胎血管生成的可视化和定量分析<em&gt;热带非洲爪蟾</em

Blood vessels supply oxygen and nutrients throughout the body, and the formation of the vascular network is under tight developmental control. The ...

Microinjection of DNA into Eyebuds in Xenopus laevis Embryos and Imaging of GFP Expressing Optic Axonal Arbors in Intact, Living Xenopus Tadpoles

The primary visual projection of tadpoles of the aquatic frog Xenopus laevis serves as an excellent model system for studying mechanisms that regulate the development of neuronal connectivity. During establishment of the retino-tectal projection, optic axons extend from the eye and navigate through distinct regions of the brain to reach their target tissue, the optic tectum. Once optic axons enter the tectum, they elaborate terminal arbors that function to increase the number of synaptic connections they can make with target interneurons in the tectum. Here, we describe a method to express DNA encoding green fluorescent protein (GFP), and gain- and loss-of-function gene constructs, in optic neurons (retinal ganglion cells) in Xenopus embryos. We explain how to microinject a combined DNA/lipofection reagent into eyebuds of one day old embryos such that exogenous genes are expressed in single or small numbers of optic neurons. By tagging genes with GFP or co-injecting with a GFP plasmid, terminal axonal arbors of individual optic neurons with altered molecular signaling can be imaged directly in brains of intact, living Xenopus tadpoles several days later, and their morphology can be quantified. This protocol allows for determination of cell-autonomous molecular mechanisms that underlie the development of optic axon arborization in vivo.

Microinjection of DNA into Eyebuds in Xenopus laevis Embryos and Imaging of GFP Expressing Optic Axonal Arbors in Intact, Living Xenopus Tadpoles

This protocol aims to demonstrate how to microinject a DNA/DOTAP mixture into eyebuds of one day old Xenopus laevis embryos, and how to image and reconstruct individual green fluorescent protein (GFP) expressing optic axonal arbors in tectal midbrains of intact, living Xenopus tadpoles.

将DNA微注射到异种胚胎的眼蕾中，以及GFP表达光学轴状轴向轴向的成像，活的Xenopus大白鼠

The primary visual projection of tadpoles of the aquatic frog Xenopus laevis serves as an excellent model system for studying mechanisms that regulate the ...

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.

荧光钙成像及其后续原位杂交，用于异种性前体特征

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 ...