Thanks to the members of the Moens lab for helpful input during the writing of this article. H.K. is post-doctoral fellow supported by NIH/NICHD grant #5R01HD037909-08. C.B.M. is an investigator with the Howard Hughes Medical Institute.

A step-by-step guide to generating targeted chimeric zebrafish embryos by transplantation at the blastula or gastrula stage.
One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an organism that contains cells from more than one animal; mosaics are one type of chimera in which cells from more than one genotype are mixed, usually wild-type and mutant. In the zebrafish, chimeras can be readily made ...

<ol>
	<li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Zebrafish Book. , (2000).</li><li>Kimmel, C. B., Warga, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+lineage+and+developmental+potential+of+cells+in+the+zebrafish+embryo.">Cell lineage and developmental potential of cells in the zebrafish embryo.</a> Trends Genet. 4, 68-74 (1988).</li><li>Kimmel, C. B., Warga, R. M., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Origin+and+organization+of+the+zebrafish+fate+map.">Origin and organization of the zebrafish fate map.</a> Development. 108, 581-594 (1990).</li><li>Woo, K., Fraser, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Order+and+coherence+in+the+fate+map+of+the+zebrafish+nervous+system.">Order and coherence in the fate map of the zebrafish nervous system.</a> Development. 121, 2595-2609 (1995).</li><li>Raz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primordial+germ-cell+development:+the+zebrafish+perspective.">Primordial germ-cell development: the zebrafish perspective.</a> Nat Rev Genet. 4, 690-700 (2003).</li><li>Yoon, C., Kawakami, K., Hopkins, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+vasa+homologue+RNA+is+localized+to+the+cleavage+planes+of+2-+and+4-cell-stage+embryos+and+is+expressed+in+the+primordial+germ+cells.">Zebrafish vasa homologue RNA is localized to the cleavage planes of 2- and 4-cell-stage embryos and is expressed in the primordial germ cells.</a> Development. 124, 3157-3165 (1997).</li><li>Koprunner, M., Thisse, C., Thisse, B., Raz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+zebrafish+nanos-related+gene+is+essential+for+the+development+of+primordial+germ+cells.">A zebrafish nanos-related gene is essential for the development of primordial germ cells.</a> Genes Dev. 15 (21), 2877-2885 (2001).</li><li>Weidinger, G., Wolke, U., Koprunner, M., Klinger, M., Raz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+tissues+and+patterning+events+required+for+distinct+steps+in+early+migration+of+zebrafish+primordial+germ+cells.">Identification of tissues and patterning events required for distinct steps in early migration of zebrafish primordial germ cells.</a> Development. 126 (23), 5295-5307 (1999).</li><li>Weidinger, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+zebrafish+primordial+germ+cell+migration+by+attraction+towards+an+intermediate+target.">Regulation of zebrafish primordial germ cell migration by attraction towards an intermediate target.</a> Development. 129 (1), 25-36 (2002).</li><li>Ciruna, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+maternal-zygotic+mutant+zebrafish+by+germ-line+replacement.">Production of maternal-zygotic mutant zebrafish by germ-line replacement.</a> Proc Natl Acad Sci U S A. 99, 14919-14924 (2002).</li><li>Waskiewicz, A. J., Rikhof, H. A., Moens, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eliminating+zebrafish+pbx+proteins+reveals+a+hindbrain+ground+state.">Eliminating zebrafish pbx proteins reveals a hindbrain ground state.</a> Dev Cell. 3, 723-733 (2002).</li><li>Weidinger, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=dead+end,+a+novel+vertebrate+germ+plasm+component,+is+required+for+zebrafish+primordial+germ+cell+migration+and+survival.">dead end, a novel vertebrate germ plasm component, is required for zebrafish primordial germ cell migration and survival.</a> Curr Biol. 13, 1429-1434 (2003).</li><li>Blaser, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transition+from+non-motile+behaviour+to+directed+migration+during+early+PGC+development+in+zebrafish.">Transition from non-motile behaviour to directed migration during early PGC development in zebrafish.</a> J Cell Sci. 118, 4027-4038 (2005).</li></ol>

The ease with which transplantation can be used to produce targeted chimeras is one of the great powers of the zebrafish as a vertebrate model. A modification of this protocol not described above allows analysis of maternal gene function for genes with essential roles in zygotic development. Since these mutant fish cannot survive until adulthood, it is necessary to transfer the mutant germline into an otherwise wild-type host embryo, creating &#x201C;germline clones&#x201D; of mutant cells. Generating germline mosaics in...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Injection rig</td>
<td>&nbsp;</td>
<td>Applied Scientific Instrumentation</td>
<td>MPPI-3</td>
<td>Foot pedal can be ordered separately</td>
</tr>
<tr>
<td>Pronase</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P5147</td>
<td>&#x201C;protease type XIV&#x201D;</td>
</tr>
<tr>
<td>Pen-Strep</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P4458</td>
<td>100x stock</td>
</tr>
<tr>
<td>Methyl cellulose</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>M-0387</td>
<td>&nbsp;</td>
<tr>
<td>Fluorescent dextrans</td>
<td>&nbsp;</td>
<td>Molecular Probes/ Invitrogen</td>
<td>various</td>
<td>Eg. lysine-fixable rhodamine dextran (D7162)</td>
</tr>
<tr>
<td>Injection pipettes (1.2mmx0.94mmx10cm)</td>
<td>&nbsp;</td>
<td>Sutter</td>
<td>BF120-94-10</td>
<td>&nbsp;</td>
<tr>
<td>Transplant pipette option 1</td>
<td>&nbsp;</td>
<td>World Precision Instruments</td>
<td>TW100-4</td>
<td>&nbsp;</td>
<tr>
<td>Transplant pipette option 2</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>#53508-400</td>
<td>&nbsp;</td>
<tr>
<td>micromanipulator</td>
<td>&nbsp;</td>
<td>Narishige</td>
<td>UMJ-3FC (?)</td>
<td>&nbsp;</td>
<tr>
<td>Micromanipulator magnetic stand</td>
<td>&nbsp;</td>
<td>Narishige</td>
<td>GJ-1</td>
<td>&nbsp;</td>
<tr>
<td>Transplant apparatus</td>
<td>&nbsp;</td>
<td>Sutter Instrument Co. </td>
<td>MI-10010</td>
<td>&nbsp;</td>
<tr>
<td>Fine micromanipulator</td>
<td>&nbsp;</td>
<td>Narishige</td>
<td>MMO-203</td>
<td>&nbsp;</td>
<tr>
<td>Depression slides</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>12560A</td>
<td>&nbsp;</td>
<tr>
<td>Agar molds for injection and transplants</td>
<td>&nbsp;</td>
<td>AL-AN Mfg, Inc.</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>
			<div>
			Reagents: Recipes for many of the reagents used for these procedures are found in The Zebrafish Book, which is available in full online at <a href="http://zfin.org/zf_info/zfbook/zfbk.html">http://zfin.org/zf_info/zfbook/zfbk.html</a>. Recipes are provided there for preparation of Fish Water, Embryo Medium with and without antibiotics, pronase for dechorionating, fluorescent dextrans, and methyl cellulose.		</div>

generating chimeric zebrafish embryos by transplantation

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an organism that contains cells from more than one animal; mosaics are one type of chimera in which cells from more than one genotype are mixed, usually wild-type and mutant. In the zebrafish, chimeras can be readily made by transplantation of cells from a donor embryo into a host embryo at the appropriate embryonic stage. Labeled donor cells are generated by injection of a lineage marker, such as a fluorescent dye, into the one-cell stage embryo. Labeled donor cells are removed from donor embryos and introduced into unlabeled host embryos using an oil-controlled glass pipette mounted on either a compound or dissecting microscope. Donor cells can in some cases be targeted to a specific region or tissue of the developing blastula or gastrula stage host embryo by choosing a transplantation site in the host embryo based on well-established fate maps.

Watch this Scientific Journal Video about Generating Chimeric Zebrafish Embryos by Transplantation at JoVE.com

Generating Chimeric Zebrafish Embryos by Transplantation

A step-by-step guide to generating targeted chimeric zebrafish embryos by transplantation at the blastula or gastrula stage.

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an ...

generating-chimeric-zebrafish-embryos-by-transplantation

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21.0K vues.  Fred Hutchinson Cancer Research Center - FHCRC. Un guide étape par étape pour générer ciblées embryons de poissons zèbres chimérique par transplantation au stade blastula ou de gastrula.

Vidéo: Generating Chimeric Zebrafish Embryos by Transplantation

A step-by-step guide to generating targeted chimeric zebrafish embryos by transplantation at the blastula or gastrula...

imaging glycans in zebrafish embryos by metabolic labeling and bioorthogonal click chemistry

Imaging Glycans in Zebrafish Embryos by Metabolic Labeling and Bioorthogonal Click Chemistry

A click-chemistry based method that allows for the rapid, noninvasive, and robust labeling of alkyne-tagged glycans in zebrafish embryos is described. Fucosylated glycans in the enveloping layer of zebrafish embryos in the late gastrulation stage were imaged in this...

laser ablation of the zebrafish pronephros to study renal epithelial regeneration

Laser Ablation of the Zebrafish Pronephros to Study Renal Epithelial Regeneration

Acute kidney injury (AKI) in humans is a common clinical problem caused by damage to the epithelial cells that comprise kidney nephrons, and AKI is associated with high mortality rates of 50-70%1.  Following epithelial cell destruction, nephrons have a limited ability to regenerate, though the mechanisms and limitations that guide this phenomenon remain poorly understood.  In this video article, we describe our technique for targeted laser ablation of kidney nephron cells in the zebrafish...

shifting zebrafish lethal skeletal mutant penetrance by progeny testing

Shifting Zebrafish Lethal Skeletal Mutant Penetrance by Progeny Testing

The goal of this protocol is to alter the penetrance of lethal skeletal mutant phenotypes in zebrafish by selective breeding. Lethal mutants cannot be grown to adulthood and bred themselves, therefore this protocol describes a method for tracking and selecting penetrance through multiple generations by progeny testing.

a simple and effective transplantation device for zebrafish embryos

A Simple and Effective Transplantation Device for Zebrafish Embryos

Embryological manipulations such as extirpation and transplantation of cells are important tools to study early development. This protocol describes a simple and effective transplantation device to perform these manipulations in zebrafish...

optogenetic activation of zebrafish somatosensory neurons using chef-tdtomato

Optogenetic Activation of Zebrafish Somatosensory Neurons using ChEF-tdTomato

Optogenetic techniques have made it possible to study the contribution of specific neurons to behavior.  We describe a method in larval zebrafish for activating single somatosensory neurons expressing a channelrhodopsin variant (ChEF) with a diode-pumped solid state (DPSS) laser and recording the elicited behaviors with a high-speed video...

surgical size reduction of zebrafish for the study of embryonic pattern scaling

Surgical Size Reduction of Zebrafish for the Study of Embryonic Pattern Scaling

Here, we describe a method for reducing the size of zebrafish embryos without disrupting normal developmental processes. This technique enables the study of pattern scaling and developmental robustness against size...

high-resolution cell transplantation in embryonic and larval zebrafish

Author Spotlight: Mapping Cellular Connectivity in the Zebrafish Nervous System During Development and Regeneration

Here we present a protocol to transplant cells with high spatial and temporal resolution in zebrafish embryos and larvae at any stage between at least 1 and 7 days post...

Robust Zebrafish Cell Transplantation for Regeneration and Development Research

https://cloudfront.jove.com/CDNSource/teasers/67218_b.jpg

High-resolution Cell Transplantation in Embryonic and Larval Zebrafish

analyzing in vivo cell migration using cell transplantations and time-lapse imaging in zebrafish embryos

Analyzing In Vivo Cell Migration using Cell Transplantations and Time-lapse Imaging in Zebrafish Embryos

Combining cell transplantation, cytoskeletal labeling and loss/gain of function approaches, this protocol describes how the migrating zebrafish prospective prechordal plate can be used to analyze the function of a candidate gene in in vivo cell migration.

Analyzing In Vivo Cell Migration using Cell Transplantations and Time-lapse Imaging in Zebrafish Embryos

in vivo imaging of transgenic gene expression in individual retinal progenitors in chimeric zebrafish embryos to study cell nonautonomous influences

In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences

Live tracking of individual WT retinal progenitors in distinct genetic backgrounds allows for the assessment of the contribution of cell non-autonomous signaling during neurogenesis. Here, a combination of gene knockdown, chimera generation via embryo transplantation and in vivo time-lapse confocal imaging was utilized for this...

In Vivo Imaging of Transgenic Gene Expression in Individual Retinal Progenitors in Chimeric Zebrafish Embryos to Study Cell Nonautonomous Influences

transplantation of gfp-expressing blastomeres for live imaging of retinal and brain development in chimeric zebrafish embryos

Transplantation of GFP-expressing Blastomeres for Live Imaging of Retinal and Brain Development in Chimeric Zebrafish Embryos

We demonstrate a protocol to generate chimeric zebrafish embryos for live imaging cellular behavior during embryogenesis.

generation of parabiotic zebrafish embryos by surgical fusion of developing blastulae

Generation of Parabiotic Zebrafish Embryos by Surgical Fusion of Developing Blastulae

This protocol provides step-by-step instruction on how to generate parabiotic zebrafish embryos of different genetic backgrounds. When combined with the unparalleled imaging capabilities of the zebrafish embryo, this method provides a uniquely powerful means to investigate cell-autonomous versus non-cell-autonomous functions for candidate genes of...

production of haploid zebrafish embryos by in vitro fertilization

Production of Haploid Zebrafish Embryos by In Vitro Fertilization

The zebrafish is a powerful model system for developmental biology and human disease research due to their genetic similarity with higher vertebrates. This protocol describes a methodology to create haploid zebrafish embryos that can be utilized for forward screen strategies to identify recessive mutations in genes essential for early...

Production of Haploid Zebrafish Embryos by In Vitro Fertilization

tissue targeted embryonic chimeras: zebrafish gastrula cell transplantation

Tissue Targeted Embryonic Chimeras: Zebrafish Gastrula Cell Transplantation

Zebrafish cell transplantation enables the combination of genetics and embryology to generate tissue specific chimeras.  This video demonstrates gastrula staged cell transplantations that have allowed our lab to investigate the roles of astroglial populations and specific guidance cues during commissure formation in the...

dechorionation of medaka embryos and cell transplantation for the generation of chimeras

Dechorionation of Medaka Embryos and Cell Transplantation for the Generation of Chimeras

Due to the hard chorion and soft embryos, manipulation of medaka embryos is more involved than in zebrafish. This video shows step-by-step procedures for how to manipulate medaka embryos, including dechorionation, mounting in agarose for imaging and cell transplantation for the production of chimeras. These procedures are essential to use medaka and zebrafish in a laboratory to take full advantage of their complementary features for the genetic dissection of vertebrate genome...

optogenetic signaling activation in zebrafish embryos

Author Spotlight: Manipulating Signaling in Zebrafish Embryos to Decode Cell Fate Decisions 

Optogenetic manipulation of signaling pathways can be a powerful strategy to investigate how signaling is decoded in development, regeneration, homeostasis, and disease. This protocol provides practical guidelines for using light-oxygen-voltage sensing domain-based Nodal and bone morphogenic protein (BMP) signaling activators in the early zebrafish...

Optogenetic Signaling Activation in Zebrafish Embryos

metabolic profile analysis of zebrafish embryos

Metabolic Profile Analysis of Zebrafish Embryos

Zebrafish represent a powerful vertebrate model that has been under-utilised for metabolic studies. Here we describe a rapid way to measure the in vivo metabolic profile of developing zebrafish that allows the comparison of different mitochondrial function parameters between genetically or pharmacologically manipulated embryos, thereby increasing the applicability of this...

long-term orthotopic transplantation of tumor cells into zebrafish embryos: an efficient method to deliver tumor cells into the fourth ventricle of zebrafish embryos for long-term analysis of tumor cell behavior

This video demonstrates the orthotopic transplantation of zebrafish brain tumor cells into the fourth ventricle of an immunocompetent zebrafish embryo. This procedure allows for the long-term study of tumor cell invasion and...

Long-term Orthotopic Transplantation of Tumor Cells into Zebrafish Embryos: An Efficient Method to Deliver Tumor Cells into the Fourth Ventricle of Zebrafish Embryos for Long-term Analysis of Tumor Cell Behavior

generation of na&#239;ve blastoderm explants from zebrafish embryos

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

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...

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

Transplantation of Whole Kidney Marrow in Adult Zebrafish

Hematopoietic stem cells (HSC) are a rare population of pluripotent cells that maintain all the differentiated blood lineages throughout the life of an organism. The functional definition of a HSC is a transplanted cell that has the ability to reconstitute all the blood lineages of an irradiated recipient long term. This designation was established by decades of seminal work in mammalian systems. Using hematopoietic cell transplantation (HCT) and reverse genetic manipulations in the mouse, the underlying regulatory factors of HSC biology are beginning to be unveiled, but are still largely under-explored. Recently, the zebrafish has emerged as a powerful genetic model to study vertebrate hematopoiesis. Establishing HCT in zebrafish will allow scientists to utilize the large-scale genetic and chemical screening methodologies available in zebrafish to reveal novel mechanisms underlying HSC regulation. In this article, we demonstrate a method to perform HCT in adult zebrafish. We show the dissection and preparation of zebrafish whole kidney marrow, the site of adult hematopoiesis in the zebrafish, and the introduction of these donor cells into the circulation of irradiated recipient fish via intracardiac injection. Additionally, we describe the post-transplant care of fish in an "ICU" to increase their long-term health. In general, gentle care of the fish before, during, and after the transplant is critical to increase the number of fish that will survive more than one month following the procedure, which is essential for assessment of long term (&lt;3 month) engraftment. The experimental data used to establish this protocol will be published elsewhere. The establishment of this protocol will allow for the merger of large-scale zebrafish genetics and transplant biology.

In this article, we demonstrate a method to perform HCT in adult zebrafish.

Hematopoietic stem cells (HSC) are a rare population of pluripotent cells that maintain all the differentiated blood lineages throughout the life of an ...

Microinjection of mRNA and Morpholino Antisense Oligonucleotides in Zebrafish Embryos.

An essential tool for investigating the role of a gene during development is the ability to perform gene knockdown, overexpression, and misexpression studies. In zebrafish (Danio rerio), microinjection of RNA, DNA, proteins, antisense oligonucleotides and other small molecules into the developing embryo provides researchers a quick and robust assay for exploring gene function in vivo. In this video-article, we will demonstrate how to prepare and microinject in vitro synthesized EGFP mRNA and a translational-blocking morpholino oligo against pkd2, a gene associated with autosomal dominant polycystic kidney disease (ADPKD), into 1-cell stage zebrafish embryos. We will then analyze the success of the mRNA and morpholino microinjections by verifying GFP expression and phenotype analysis. Broad applications of this technique include generating transgenic animals and germ-line chimeras, cell-fate mapping and gene screening. Herein we describe a protocol for overexpression of EGFP and knockdown of pkd2 by mRNA and morpholino oligonucleotide injection.

Microinjection is a well-established and effective method for introducing foreign substances into fertilized zebrafish embryos. Here, we demonstrate a robust microinjection technique for performing mRNA overexpression, and morpholino oligonucleotide gene knockdown studies in zebrafish.

An essential tool for investigating the role of a gene during development is the ability to perform gene knockdown, overexpression, and misexpression ...

Microinjection of Zebrafish Embryos to Analyze Gene Function

One of the advantages of studying zebrafish is the ease and speed of manipulating protein levels in the embryo.  Morpholinos, which are synthetic oligonucleotides with antisense complementarity to target RNAs, can be added to the embryo to reduce the expression of a particular gene product.  Conversely, processed mRNA can be added to the embryo to increase levels of a gene product.  The vehicle for adding either mRNA or morpholino to an embryo is microinjection.  Microinjection is efficient and rapid, allowing for the injection of hundreds of embryos per hour.  This video shows all the steps involved in microinjection.  Briefly, eggs are collected immediately after being laid and lined up against a microscope slide in a Petri dish.  Next, a fine-tipped needle loaded with injection material is connected to a microinjector and an air source, and the microinjector controls are adjusted to produce a desirable injection volume.  Finally, the needle is plunged into the embryo's yolk and the morpholino or mRNA is expelled.

This video shows how morpholino or mRNA can be injected into zebrafish embryos at the one-cell stage to decrease or increase the level of specific gene products during subsequent development.

One of the advantages of studying zebrafish is the ease and speed of manipulating protein levels in the embryo.  Morpholinos, which are synthetic ...

Certain fundamental questions in the field of developmental biology can only be answered when cells are placed in novel environments or when small groups of cells in a larger context are altered.  Watching how one cell interacts with and behaves in a unique environment is essential to characterizing cell functions.  Determining how the localized misexpression of a specific protein influences surrounding cells provides insightful information on the roles that protein plays in a variety of developmental processes.  Our lab uses the zebrafish model system to uniquely combine genetic approaches with classical transplantation techniques to generate genotypic or phenotypic chimeras.  We study neuron-glial cell interactions during the formation of forebrain commissures in zebrafish. This video describes a method that allows our lab to investigate the role of astroglial populations in the diencephalon and the roles of specific guidance cues that influence projecting axons as they cross the midline. Due to their transparency zebrafish embryos are ideal models for this type of ectopic cell placement or localized gene misexpression. Tracking transplanted cells can be accomplished using a vital dye or a transgenic fish line expressing a fluorescent protein. We demonstrate here how to prepare donor embryos with a vital dye tracer for transplantation, as well as how to extract and transplant cells from one gastrula staged embryo to another.  We present data showing ectopic GFP+ transgenic cells within the forebrain of zebrafish embryos and characterize the location of these cells with respect to forebrain commissures.  In addition, we show laser scanning confocal timelapse microscopy of Alexa 594 labeled cells transplanted into a GFP+ transgenic host embryo.  These data provide evidence that gastrula staged transplantation enables the targeted positioning of ectopic cells to address a variety of questions in Developmental Biology.

Zebrafish cell transplantation enables the combination of genetics and embryology to generate tissue specific chimeras. This video demonstrates gastrula staged cell transplantations that have allowed our lab to investigate the roles of astroglial populations and specific guidance cues during commissure formation in the forebrain.

Certain fundamental questions in the field of developmental biology can only be answered when cells are placed in novel environments or when small groups ...

Two-Photon-Based Photoactivation in Live Zebrafish Embryos

Photoactivation of target compounds in a living organism has proven a valuable approach to investigate various biological processes such as embryonic development, cellular signaling and adult physiology. In this respect, the use of multi-photon microscopy enables quantitative photoactivation of a given light responsive agent in deep tissues at a single cell resolution. As zebrafish embryos are optically transparent, their development can be monitored in vivo. These traits make the zebrafish a perfect model organism for controlling the activity of a variety of chemical agents and proteins by focused light. Here we describe the use of two-photon microscopy to induce the activation of chemically caged fluorescein, which in turn allows us to follow cell's destiny in live zebrafish embryos. We use embryos expressing a live genetic landmark (GFP) to locate and precisely target any cells of interest. This procedure can be similarly used for precise light induced activation of proteins, hormones, small molecules and other caged compounds.

Multiphoton microscopy allows control of low energy photons with deep optical penetration and reduced phototoxicity. We describe the use of this technology for live cell labeling in zebrafish embryos. This protocol can be readily adapted for photo-induction of various light-responsive molecules.

Photoactivation of target compounds in a living organism has proven a valuable approach to investigate various biological processes such as embryonic ...

Cells change extensively in their locations and property during embryogenesis. These changes are regulated by the interactions between the cells and their environment. Chimeric embryos, which are composed of cells of different genetic background, are great tools to study the cell-cell interactions mediated by genes of interest. The embryonic transparency of zebrafish at early developmental stages permits direct visualization of the morphogenesis of tissues and organs at the cellular level. Here, we demonstrate a protocol to generate chimeric retinas and brains in zebrafish embryos and to perform live imaging of the donor cells. The protocol covers the preparation of transplantation needles, the transplantation of GFP-expressing donor blastomeres to GFP-negative hosts, and the examination of donor cell behavior under live confocal microscopy. With slight modifications, this protocol can also be used to study the embryonic development of other tissues and organs in zebrafish. The advantages of using GFP to label donor cells are also discussed. 

We demonstrate a protocol to generate chimeric zebrafish embryos for live imaging cellular behavior during embryogenesis.

Cells change extensively in their locations and property during embryogenesis. These changes are regulated by the interactions between the cells and their ...

Medaka is a small egg-laying freshwater fish that allows both genetic and embryological analyses and is one of the three vertebrate model organisms in which genome-wide phenotype-driven mutant screens were carried out 1. Divergence of functional overlap of related genes between medaka and zebrafish allows identification of novel phenotypes that are unidentifiable in a single species 2, thus medaka and zebrafish are complementary for genetic dissection of the vertebrate genome functions. Manipulation of medaka embryos, such as dechorionation, mounting embryos for imaging and cell transplantation, are key procedures to work on both medaka and zebrafish in a laboratory. Cell transplantation examines cell autonomy of medaka mutations. Chimeras are generated by transplanting labeled cells from donor embryos into unlabeled recipient embryos. Donor cells can be transplanted to specific areas of the recipient embryos based on the fate maps 3 so that clones from transplanted cells can be integrated in the tissue of interest during development. Due to the hard chorion and soft embryos, manipulation of medaka embryos is more involved than in zebrafish. In this video, we show detailed procedures to manipulate medaka embryos.

Due to the hard chorion and soft embryos, manipulation of medaka embryos is more involved than in zebrafish. This video shows step-by-step procedures for how to manipulate medaka embryos, including dechorionation, mounting in agarose for imaging and cell transplantation for the production of chimeras. These procedures are essential to use medaka and zebrafish in a laboratory to take full advantage of their complementary features for the genetic dissection of vertebrate genome functions.

Medaka is a small egg-laying freshwater fish that allows both genetic and embryological analyses and is one of the three vertebrate model organisms in ...

Imaging glycans in vivo has recently been enabled using a bioorthogonal chemical reporter strategy by treating cells or organisms with azide- or alkyne-tagged monosaccharides1, 2. The modified monosaccharides, processed by the glycan biosynthetic machinery, are incorporated into cell surface glycoconjugates. The bioorthogonal azide or alkyne tags then allow covalent conjugation with fluorescent probes for visualization, or with affinity probes for enrichment and glycoproteomic analysis. This protocol describes the procedures typically used for noninvasive imaging of fucosylated glycans in zebrafish embryos, including: 1) microinjection of one-cell stage embryos with GDP-5-alkynylfucose (GDP-FucAl), 2) labeling fucosylated glycans in the enveloping layer of zebrafish embryos with azide-conjugated fluorophores via biocompatible Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), and 3) imaging by confocal microscopy3. The method described here can be readily extended to visualize other classes of glycans, e.g. glycans containing sialic acid4 and N-acetylgalactosamine5, 6, in developing zebrafish and in other living organisms.

A click-chemistry based method that allows for the rapid, noninvasive, and robust labeling of alkyne-tagged glycans in zebrafish embryos is described. Fucosylated glycans in the enveloping layer of zebrafish embryos in the late gastrulation stage were imaged in this study.

Imaging glycans in vivo has recently been enabled using a bioorthogonal chemical reporter strategy by treating cells or organisms with azide- or ...

Transplantation of Cells Directly into the Kidney of Adult Zebrafish

Regenerative medicine based on the transplantation of stem or progenitor cells into damaged tissues has the potential to treat a wide range of chronic diseases1. However, most organs are not easily accessible, necessitating the need to develop surgical methods to gain access to these structures. In this video article, we describe a method for transplanting cells directly into the kidney of adult zebrafish, a popular model to study regeneration and disease2. Recipient fish are pre-conditioned by irradiation to suppress the immune rejection of the injected cells3. We demonstrate how the head kidney can be exposed by a lateral incision in the flank of the fish, followed by the injection of cells directly in to the organ. Using fluorescently labeled whole kidney marrow cells comprising a mixed population of renal and hematopoietic precursors, we show that nephron progenitors can engraft and differentiate into new renal tissue - the gold standard of any cell-based regenerative therapy. This technique can be adapted to deliver purified stem or progenitor cells and/or small molecules to the kidney as well as other internal organs and further enhances the zebrafish as a versatile model to study regenerative medicine.

Cell transplantation is an essential technique for studying tissue regeneration and for developing cell-based therapies of disease. We demonstrate here a microsurgical technique that permits the transplantation of genetically labeled cells directly into the kidney of adult zebrafish fish.

Regenerative medicine based on the transplantation of stem or progenitor cells into damaged tissues has the potential to treat a wide range of chronic ...

A growing goal in the field of metabolism is to determine the impact of genetics on different aspects of mitochondrial function. Understanding these relationships will help to understand the underlying etiology for a range of diseases linked with mitochondrial dysfunction, such as diabetes and obesity. Recent advances in instrumentation, has enabled the monitoring of distinct parameters of mitochondrial function in cell lines or tissue explants. Here we present a method for a rapid and sensitive analysis of mitochondrial function parameters in vivo during zebrafish embryonic development using the Seahorse bioscience XF 24 extracellular flux analyser. This protocol utilizes the Islet Capture microplates where a single embryo is placed in each well, allowing measurement of bioenergetics, including: (i) basal respiration; (ii) basal mitochondrial respiration (iii) mitochondrial respiration due to ATP turnover; (iv) mitochondrial uncoupled respiration or proton leak and (iv) maximum respiration. Using this approach embryonic zebrafish respiration parameters can be compared between wild type and genetically altered embryos (mutant, gene over-expression or gene knockdown) or those manipulated pharmacologically. It is anticipated that dissemination of this protocol will provide researchers with new tools to analyse the genetic basis of metabolic disorders in vivo in this relevant vertebrate animal model.

Zebrafish represent a powerful vertebrate model that has been under-utilised for metabolic studies. Here we describe a rapid way to measure the in vivo metabolic profile of developing zebrafish that allows the comparison of different mitochondrial function parameters between genetically or pharmacologically manipulated embryos, thereby increasing the applicability of this organism.

A growing goal in the field of metabolism is to determine the impact of genetics on different aspects of mitochondrial function. Understanding these ...