Diese Arbeit wird durch ein Start-up Fund aus dem Department of Biological Sciences an der Purdue University unterstützt.

Teil 1: Vorbereitungen vor Mikrodissektion <ol><li> Lösungen <ol class="lalpha"><li> E3 Medium 4 (5 mM NaCl, 0,17 mM KCl, 0,33 mM CaCl 2 und 0,33 mM MgSO 4). </li><li> Ringer-Lösung 1, 5 (116 mM NaCl, 2,9 mM KCl, 1,8 mM CaCl 2, 5 mM HEPES, pH 7,2), sterilfiltriert. </li><li> 5N NaOH. </li></ol></li><li> Chemisches Ätzen von Wolfram Nadeln <ol class="lalpha"><li> Sichern Sie sich einen kleinen Becher mit 5N NaOH auf einer Petrischale mit Ton. </li><li> Bringen Sie eine Büroklammer auf der Seite des Bechers, so dass es in Kontakt mit der NaOH-Lösung kommt. </li><li> Verbinden Sie die negative Elektrode aus einer DC-Stromversorgung, die Büroklammer und die positive Elektrode an einem Ende ein kurzes Stück (~ 2cm) aus Wolframdraht. </li><li> Wickeln Sie das andere Ende des Wolfram-Draht mit einem kleinen Ton-Ball und dip diesem Zweck in die NaOH-Lösung. </li><li> Erhöhen Sie die Spannung auf ca. 3V und tauchen den Draht nach oben und unten in der NaOH-Lösung, bis eine gute Ätzrate erreicht ist. Eine Nadel in guter Qualität können in der Regel in 10 Minuten geätzt werden. </li><li> Der Wolframdraht der Lösung ausgesetzt wird allmählich dünner. Wenn der Ton Kugel abfällt, wird die andere Seite der Leitung, die noch auf der positiven Elektrode angebracht haben eine spitze Nadel Form. </li><li> Spülen Sie die spitze Nadel mit Ringer-Lösung oder E3 zu Salzablagerungen zu entfernen. </li><li> Befestigen Sie die Nadel zu einem Holzstab durch Band oder einen Nadelhalter für eine einfache Handhabung. </li></ol></li><li> Kultur-Platten <ol class="lalpha"><li> Die Falcon 60 x 15 mm Polystyrol Kultur Platten sind bereit, für Netzhaut-Mikrodissektion verwendet werden. </li><li> Für Sezieren RPE-attached Netzhaut, crush zwei Embryonen völlig in einer Kultur Platte mit Ringer-Lösung, um loszuwerden, die Haftfähigkeit der Oberfläche 30 Minuten vor dem Sezieren. Kurz vor ihrer Zerlegung, waschen Sie die Platte intensiv mit frischer Ringerlösung. </li></ol></li><li> Embryonen Sammlung und Inszenierung <ol class="lalpha"><li> Adult Zebrafisch erhalten bleiben, wie beschrieben 4, 5. </li><li> Trennen Sie die Eltern Fisch in statischen Zuchtbecken durch einen Teiler paarweise in der Nacht zuvor Zucht. </li><li> Entfernen Sie die Trennlinie nach dem Raumlicht eingeschaltet ist am nächsten Morgen geworden. Lassen Sie die Eltern, um im 10-Minuten-Takt Cross jede halbe Stunde. Trennen Sie die Fische nach jeder Kreuzung. </li><li> Pflegen Sie die Embryonen aus jeder Kreuzung in E3 Medium getrennt gesammelt bei 28 ° C. </li><li> Embryonen bei 10 bis 12 Stunden nach der Befruchtung (HPF) und reinszenieren unmittelbar vor Dissektion an der bestimmten Zeitpunkten, nach festgelegten Kriterien 1, 6. </li></ol></li></ol> Teil 2: Dissection - Gehirn entfernt und Auge Belichtung 1 <ul><li> Die Verfahren in diesem Abschnitt beschrieben sind häufig zum Präparieren Netzhaut (Teil 3A) und RPE-attached Netzhaut (3b). </li><li> Alle feinen Sektionen werden von einer Spitze des Dumont Pinzetten getan und unterstützt durch ein anderes Paar von Dumont Pinzetten zur Positionierung des Gewebes. Ein chemisch geätzten Wolframnadel kann für eine feinere Manipulationen bei Bedarf verwendet werden. </li><li> Alle feinen Dissektionen sind bei ~ 5-8fache Vergrößerung unter einem SZX16 Mikroskop mit einem 1X Ziel oder gleichwertig ausgestattet war. </li><li> Pflegen Sie die Embryonen in E3-Medium in einem Tischgerät Brutschrank bei 28 ° C neben dem Mikroskop leicht Embryo Zugang beim Präparieren. </li><li> Der Mikroskoptisch ist bis 28 ° C durch eine thermo Platte erwärmt, um den Einfluss von Temperaturschwankungen auf die Genexpression zu minimieren. </li></ul><ol><li> Transfer eines Embryos zu einem bestimmten Entwicklungsstadium an Ringer-Lösung in einem Falcon 60 X 15 mm Kulturplatte hergestellt, wie in Teil 1 # 3 beschrieben. </li><li> Schneiden Sie den Kopf mit einem Teil der vorderen Kofferraum schnell aus dem Körper. </li><li> Pin das hintere Ende dieses Gewebes auf die Kultur Platte mit der Unterstützung der Pinzette. </li><li> Öffnen Sie den Kopf auf der Rückenseite ab der vorderen Stirn. </li><li> Entfernen Sie das Gehirn, so dass die mediale Seite der Augen ausgesetzt ist und nach oben gerichtet ist für weitere Manipulationen. </li></ol> Teil 3a: Retinal Dissektion 1 <ol><li> Bereiten Sie den Embryo als in Teil 2 beschrieben. </li><li> Gründlich abbürsten der exponierten RPE auf der medialen Seite des Augapfels, die nach oben durch die Spitze der Zange, bis eine kleine Öffnung auf der Netzhaut zu sehen ist. </li><li> Setzen Sie die Bürsten und Peeling Aktion bis der medialen Seite der Netzhaut fast alle ausgesetzt sind. Vermeiden Sie Kratzer und Stanzen der exponierten Netzhaut. </li><li> Um die seitliche RPE auf der Netzhaut, die nun vor nach unten, Ansatz entfernen, und Bürste in einem Winkel von ca. 45 ° von der Kultur Plattenoberfläche. </li><li> Entfernen Sie das RPE, die relativ fest an der ora serrata befestigt durch Pinning der abgelösten Teil des RPE, die culture Platte für die Präparation und heben Sie dann die Netzhaut sanft. </li><li> Rolle der Netzhaut auf dem Boden der Kulturschale zu bereinigen die restliche RPE. <ol class="lalpha"><li> Wir haben bemerkt, dass diese besondere Falcon Polystyrol Kulturplatte Vorzugspreis Einhaltung der RPE für ca. 20 Minuten einmal ein Embryo ist gebrochen. Diese Eigenschaft ist für die Entfernung von RPE Reste eingesetzt. Allerdings sind die Zellen der Netzhaut-Stick an die Oberfläche zu einem geringeren Teil, die eng unter hoher Vergrößerung untersucht werden. Man muss ein Gleichgewicht zwischen der Vollständigkeit der RPE Entfernung und Retina Integrität zu schlagen. </li><li> Das Objektiv oft hält sich an die Kultur Platte und löst sich von der Netzhaut beim Walzen. Gelegentlich ist es notwendig, die Linse durch eine geätzte Wolframnadel lösen mit einem wirbelnden Wirkung auf die Oberfläche der Linse. </li></ol></li><li> Diese Verfahren können erfolgreich beseitigt RPE von der Netzhaut, ohne dabei die Integrität des Gewebes. Dies wird durch eine insgesamt gute Morphologie (Abbildung 1B und B &#39;) und Histologie (Abbildung 1B &quot;) angegeben, Pfeil Insbesondere die Erhaltung der extrazellulären Matrix zwischen den Photorezeptor-Schicht und der RPE außergewöhnlich gut ist (Abbildung 1B.&quot; Vergleich mit der Histologie aus der ganzen Embryo (Abbildung 1A &quot;)). </li></ol> Teil 3b: RPE-attached Netzhaut Dissektion 3 <ol><li> Bereiten Sie den Embryo als in Teil 2 beschrieben. </li><li> Pin den Kopf, um die Kultur Platte vom Assistenten Pinzette. Heben Sie das Auge vorsichtig aus dem hinteren lateralen Seite und rollen auf der Vorderseite. <ol class="lalpha"><li> Die mutmaßlichen Aderhaut und Skleralgewebe auf der Außenseite des RPE Schicht relativ dicht an der Haut befestigt und kann meist abgezogen werden durch Rollen der Augen sorgfältig auf die Vorderseite. </li></ol></li><li> Nehmen Sie das Objektiv mit einer Wolfram-Nadel nach der lateralen Seite des Auges ausgesetzt ist, und wenn das Auge ist immer noch auf der Haut angebracht. </li><li> Diese Verfahren können mit Erfolg in der ganzen RPE-Schicht mit der Netzhaut. Mutmaßlich Choroidea und Skleralgewebe weitgehend entfernt werden (Abbildung 1C, C &#39;und C &quot;). </li></ol> Teil 4: Tissue Probenentnahme für die RNA-Arbeiten <ol><li> Die seziert Proben können in TRIzol in ein RNase-freies Mikrozentrifugenröhrchen für nachgeschaltete RNA Charakterisierung als vor 1 beschrieben gesammelt werden. </li></ol> Repräsentative Ergebnisse <img src="/files/ftp_upload/2028/2028fig1.jpg" alt="Abbildung 1" /> Abbildung 1. (A) Laterale und (A &#39;) Dorsalansicht eines Zebrafisch-Larven Kopf bei 52 hpf vor ihrer Zerlegung. (A &quot;) die entsprechenden histologischen Schnitt der larvalen Kopf in (A) &amp; (A &#39;). (B) Laterale und (B&#39;) Dorsalansicht eines seziert Netzhaut bei 54 hpf. Die Oberfläche der Netzhaut intakt war von beiden seitlichen und dorsalen Aussicht. (B &quot;) die entsprechenden histologischen Schnitt des seziert Netzhaut in (B) und (B &#39;). Die Struktur der Netzhaut und des retinalen Laminierung war intakt. Insbesondere die extrazelluläre Matrix zwischen den Photorezeptorschicht und RPE (A &quot;(, Pfeile war, Pfeile) sowie in den sezierten Netzhaut B) erhalten.&quot; (C) Quer-und (C &#39;) medialen Darstellung eines seziert RPE-attached Netzhaut bei 52 hpf. RPE-Schicht intakt war und kontinuierliche, was auch durch die histologischen Schnitt des sezierten Gewebes (C &quot;) angegeben. Der weiße Bereich in C &#39;ist der Sehnerv (Pfeil). Für Histologie, Gewebeproben gesammelt und in 4% Paraformaldehyd. Plastic Einbettung und Schneiden dieser Proben wurden wie 3 beschrieben. Scale-bar = 50 pm.

<ol>
	<li>Leung, Y. F., Dowling, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+expression+profiling+of+zebrafish+embryonic+retina.">Gene expression profiling of zebrafish embryonic retina.</a> Zebrafish. 2, 269-283 (2005).</li><li>Leung, Y. F., Ma, P., Link, B. A., Dowling, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factorial+microarray+analysis+of+zebrafish+retinal+development.">Factorial microarray analysis of zebrafish retinal development.</a> Proc Natl Acad Sci U S A. 105, 12909-12914 (2008).</li><li>Leung, Y. F., Ma, P., Dowling, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+expression+profiling+of+zebrafish+embryonic+retinal+pigment+epithelium+in+vivo.">Gene expression profiling of zebrafish embryonic retinal pigment epithelium in vivo.</a> Invest Ophthalmol Vis Sci. 48, 881-890 (2007).</li><li>Nusslein-Volhard, C., Dahm, R. <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 : a practical approach. , (2002).</li><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=The+zebrafish+book+:+a+guide+for+the+laboratory+use+of+zebrafish+(Danio+rerio).">The zebrafish book : a guide for the laboratory use of zebrafish (Danio rerio).</a> , (2000).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., 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=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev Dyn. 203, 253-310 (1995).</li><li>Fadool, J. M., Dowling, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish:+a+model+system+for+the+study+of+eye+genetics.">Zebrafish: a model system for the study of eye genetics.</a> Prog Retin Eye Res. 27, 89-110 (2008).</li></ol>

Tierversuche wurden in Übereinstimmung mit den Richtlinien und Vorschriften her von Purdue Animal Care und Verwenden Ausschusses durchgeführt.

Mikrodissektion von Zebrafisch Augengewebe effektiv erhalten intakte Netzhaut und RPE-attached Netzhaut. Diese im Wesentlichen unterstützt Ausdruck Studien in Bezug auf ein bestimmtes Augengewebes (dh Netzhaut oder RPE). In der Tat haben wir erfolgreich diese Verfahren genutzt werden, um RNA Expressionsprofile der ganze Netzhaut 1 und RPE 3 zu erhalten. Der Nutzen dieser Profile ist stark von unserer letzten Identifizierung von Wegen und Gen-Familien, die in einem Retina-Differenzierung mutierten ...

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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>Cordless pestle motor</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>47747-370</td>
<td>&nbsp;</td>
<tr>
<td>DC power supply</td>
<td>&nbsp;</td>
<td>Lascar</td>
<td>PSU130</td>
<td>Any DC supply would work. The specific voltage of a different machine will need further optimization.</td>
</tr>
<tr>
<td>Disposable pestle &amp; microtube, 1.5 mL (DNase, RNase and pyrogen-free)</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>47747-366</td>
<td>These are used for tissue collection in TRIzol for expression analysis.</td>
</tr>
<tr>
<td>Dumont #5 forceps, Tips: 0.05 x 0.01mm, Inox</td>
<td>&nbsp;</td>
<td>World Precision Instruments</td>
<td>500341</td>
<td>Fine tip dimension is desirable but is not inflexible, as one may need to sharpen the tip from time to time.</td>
</tr>
<tr>
<td>Dumont #5SF forceps, Tips: 0.025 x 0.005mm, Inox</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>11252-00</td>
<td>Fine tip dimension is desirable but is not inflexible, as one may need to sharpen the tip from time to time.</td>
</tr>
<tr>
<td>Falcon polystyrene culture plates, 60 X 15 mm</td>
<td>&nbsp;</td>
<td>BD Biosciences</td>
<td>351007</td>
<td>These plates are used as dissection plates.</td>
</tr>
<tr>
<td>Olympus SZX16 Stereomicroscope</td>
<td>&nbsp;</td>
<td>Olympus</td>
<td>SZX16</td>
<td>Any stereomicroscope would work. We used Leica stereomicroscope in previous studies1-3 without any issues. We also use the 1X objective exclusively for the dissection even though we have a 2X objective installed. </td>
</tr>
<tr>
<td>Sharpening stone</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>29008-01</td>
<td>Use this to sharpen the tip of the forceps if necessary</td>
</tr>
<tr>
<td>Thermo plate</td>
<td>&nbsp;</td>
<td>Tokai Hit</td>
<td>MATS-U55SZX2B</td>
<td>This is used to maintain the temperature of the tissue throughout dissection and minimize the influence of temperature fluctuation on gene expression. We also put the whole microscope in an environmentally controlled room at 28&deg;C during dissection in previous studies1-3 with good success.</td>
</tr>
<tr>
<td>Trizol, 100 mL</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15596-026</td>
<td>&nbsp;</td>
<tr>
<td>tungsten wire, 0.015 inch diameter</td>
<td>&nbsp;</td>
<td>World Precision Instruments</td>
<td>TGW1510</td>
<td>&nbsp;</td>
<tr>
<td>Wooden Applicator</td>
<td>&nbsp;</td>
<td>Puritan</td>
<td>807</td>
<td>This is used for holding the chemically-etched tungsten needle.</td>
</tr>		</tbody>
		</table>
		</div>

microdissection of zebrafish embryonic eye tissues

Zebrafisch ist ein beliebter Tiermodell zur Erforschung der Entwicklung des Auges wegen seiner schnellen<em&gt; Ex utero</em&gt; Entwicklung und gute Fruchtbarkeit. Von 3 Tagen nach der Befruchtung (DPF), werden die Larven zeigen die erste visuelle Antwort. Viele Gene sind identifiziert worden, um eine ordnungsgemäße Entwicklung des Auges steuern, aber wir sind weit von einem vollständigen Verständnis der zugrunde liegenden genetischen Architektur. Whole Genome Genexpressions-Profiling ist ein nützliches Werkzeug, um Genregulationsnetzwerk für Entwicklung des Auges zu erläutern. Allerdings macht die geringe Größe des embryonalen Auges in Zebrafisch es schwierig, intakt und rein Augengewebe für die Expression Analyse zu erhalten. Zum Beispiel ist die anterior-posterior Länge des Auges zwischen Tag 2 und 3 nur etwa 200-300 um, während der Durchmesser der Linse ist weniger 100 um. Außerdem ist das retinale Pigmentepithel (RPE) der Netzhaut zugrunde liegende nur ein Single-Layer-Epithel. Während Genexpressionsprofile aus der ganzen Embryos gewonnen werden können, tun sie nicht genau die Expression dieser Gewebe. Deshalb reine Gewebe muss für eine erfolgreiche Genexpressionsanalysen von der Entwicklung des Auges erreicht werden. Um dieses Problem anzugehen, haben wir einen Ansatz zur intakten Netzhaut und der Netzhaut mit RPE 1 bis 3 dpf angebracht, die wichtigsten Stadien der Morphogenese Auge abdecken microdissect entwickelt. Alle Vorgänge können mit feinen Pinzetten und allgemeinen Laborbedarf unter Standard-Stereomikroskope durchgeführt werden. Für Netzhaut Dissektion ist die Single-Layer-RPE entfernt und durch Bürsten Aktion und die bevorzugte Einhaltung der RPE Reste auf der Oberfläche der Kulturplatte für die Präparation geschält. Für RPE-attached Netzhaut Dissektion, ist die Einhaltung von RPE der Dissektion Platte vor der Dissektion entfernt, so dass der RPE vollständig mit der Retina erhalten. Eine sorgfältige Hubwirkung dieses Gewebes können effizient trennen die mutmaßlichen Ader-und Lederhaut. Die Linse kann in beiden Fällen durch eine chemisch geätzt Wolframnadel entfernt werden. Kurz gesagt, unser Ansatz erhalten intakte Auge Gewebe und wurde erfolgreich genutzt, um Gewebe-spezifische Expression Profile der Zebrafisch-Retina-Studie<sup&gt; 1, 2</sup&gt; Und Pigmentepithel<sup&gt; 3</sup&gt;.

Watch this Scientific Journal Video about Microdissection of Zebrafish Embryonic Eye Tissues at JoVE.com

Microdissection of Zebrafish Embryonic Eye Tissues

Dieser Artikel beschreibt einen Ansatz zur Zebrafisch Retina mit und ohne Pigmentepithel angebracht, von einem bis drei Tagen der Befruchtung Embryonen microdissect.

Mikrodissektion von Zebrafisch Embryonale Augentücher

Zebrafish is a popular animal model for research on eye development because of its rapid ex utero development and good fecundity. By 3 days post ...

microdissection-of-zebrafish-embryonic-eye-tissues

Research

JoVE Journal

Biology

16.0K Aufrufe.  Purdue University. Dieser Artikel beschreibt einen Ansatz zur Zebrafisch Retina mit und ohne Pigmentepithel angebracht, von einem bis drei Tagen der Befruchtung Embryonen microdissect.

Serie: Microdissection of Zebrafish Embryonic Eye Tissues

Laser Capture Microdissection of Mammalian Tissue

Laser capture microscopy, also known as laser microdissection (LMD), enables the user to isolate small numbers of cells or tissues from frozen or formalin-fixed, paraffin-embedded tissue sections. LMD techniques rely on a thermo labile membrane placed either on top of, or underneath, the tissue section. In one method, focused laser energy is used to melt the membrane onto the underlying cells, which can then be lifted out of the tissue section. In the other, the laser energy vaporizes the foil along a path "drawn" on the tissue, allowing the selected cells to fall into a collection device. Each technique allows the selection of cells with a minimum resolution of several microns. DNA, RNA, protein, and lipid samples may be isolated and analyzed from micro-dissected samples. In this video, we demonstrate the use of the Leica AS-LMD laser microdissection instrument in seven segments, including an introduction to the principles of LMD, initializing the instrument for use, general considerations for sample preparation, mounting the specimen and setting up capture tubes, aligning the microscope, adjusting the capture controls, and capturing tissue specimens. Laser-capture micro-dissection enables the investigator to isolate samples of pure cell populations as small as a few cell-equivalents. This allows the analysis of cells of interest that are free of neighboring contaminants, which may confound experimental results.

Laser Capture Mikrodissektion von Säugetiergewebe

Laser capture microscopy, also known as laser microdissection (LMD), enables the user to isolate small numbers of cells or tissues from frozen or ...

Forschung

Biologie

Live Imaging of the Zebrafish Embryonic Brain by Confocal Microscopy

In this video, we demonstrate the method our lab has developed to analyze the cell shape changes and rearrangements required to bend and fold the developing zebrafish brain (Gutzman et al, 2008). Such analysis affords a new understanding of the underlying cell biology required for development of the 3D structure of the vertebrate brain, and significantly increases our ability to study neural tube morphogenesis. The embryonic zebrafish brain is shaped beginning at 18 hours post fertilization (hpf) as the ventricles within the neuroepithelium inflate. By 24 hpf, the initial steps of neural tube morphogenesis are complete. Using the method described here, embryos at the one cell stage are injected with mRNA encoding membrane-targeted green fluorescent protein (memGFP). After injection and incubation, the embryo, now between 18 and 24 hpf, is mounted, inverted, in agarose and imaged by confocal microscopy. Notably, the zebrafish embryo is transparent making it an ideal system for fluorescent imaging. While our analyses have focused on the midbrain-hindbrain boundary and the hindbrain, this method could be extended for analysis of any region in the zebrafish to a depth of 
80-100 &mu;m.

In this video, we demonstrate a method by which to analyze the developing vertebrate brain in live zebrafish embryos at single cell resolution by confocal microscopy. This includes the method by which we inject the single-cell zebrafish embryo and subsequently mount and image the developing brain.

Live-Imaging der Zebrafisch embryonalen Gehirn durch konfokale Mikroskopie

In this video, we demonstrate the method our lab has developed to analyze the cell shape changes and rearrangements required to bend and fold the ...

Lens Transplantation in Zebrafish and its Application in the Analysis of Eye Mutants

The lens plays an important role in the development of the optic cup[1,2]. Using the zebrafish as a model organism, questions regarding lens development can be addressed. The zebrafish is useful for genetic studies due to several advantageous characteristics, including small size, high fecundity, short lifecycle, and ease of care. Lens development occurs rapidly in zebrafish. By 72 hpf, the zebrafish lens is functionally mature [3]. Abundant genetic and molecular resources are available to support research in zebrafish. In addition, the similarity of the zebrafish eye to those of other vertebrates provides basis for its use as an excellent animal model of human defects[4-7]. Several zebrafish mutants exhibit lens abnormalities, including high levels of cell death, which in some cases leads to a complete degeneration of lens tissues [8]. To determine whether lens abnormalities are due to intrinsic causes or to defective interactions with the surrounding tissues, transplantation of a mutant lens into a wild-type eye is performed. Using fire-polished metal needles, mutant or wild-type lenses are carefully dissected from the donor animal, and transferred into the host. To distinguish wild-type and mutant tissues, a transgenic line is used as the donor. This line expresses membrane-bound GFP in all tissues, including the lens. This transplantation technique is an essential tool in the studies of zebrafish lens mutants.

Lens development involves interactions with other tissues. Several zebrafish eye mutants are characterized by an abnormally small lens size. Here we demonstrate a lens transplantation experiment to determine whether this phenotype is due to intrinsic causes or defective interactions with tissues that surround the lens.

Objektiv Transplantation in Zebrafisch und ihre Anwendung in der Analyse von Eye-Mutanten

The lens plays an important role in the development of the optic cup[1,2]. Using the zebrafish as a model organism, questions regarding lens development ...

Tissue Targeted Embryonic Chimeras: Zebrafish Gastrula Cell Transplantation

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.

Tissue Gezielte Embryonale Chimären: Zebrafisch Gastrula Cell Transplantation

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

RNA Isolation from Embryonic Zebrafish and cDNA Synthesis for Gene Expression Analysis

Many important and complex laboratory procedures require an input of high quality, intact RNA.  A degraded sample or the presence of impurities can lead to disastrous results in downstream experimental applications.  It is therefore, of utmost importance to use solid techniques with numerous safeguards and quality control checks to ensure a superior sample.  Herein, we detail a protocol to isolate total RNA from whole zebrafish embryos using a commercially available chemical denaturant and subsequent cleanup to remove traces of DNA and impurities using a commercial RNA isolation kit. As RNA is relatively unstable and easily prone to cleavage by RNAses, most protocols assay gene expression using a cDNA product that is directly synthesized from an RNA template. We detail a procedure to convert RNA into the more stable cDNA product using a commercially available kit. Throughout these procedures there are numerous quality control checks to ensure that the sample is not degraded or contaminated.  The end product of these protocols is cDNA that is suitable for microarray analysis, RT-PCR or long-term storage.    

The isolation of high quality, intact RNA is an essential step in many laboratory protocols. Here, we demonstrate RNA extraction from whole zebrafish embryos and cDNA synthesis for subsequent application in various experimental procedures including gene expression microarray analysis.

RNA Isolation aus embryonalen Zebrafisch und cDNA-Synthese für die Genexpressionsanalyse

Many important and complex laboratory procedures require an input of high quality, intact RNA.  A degraded sample or the presence of impurities can lead ...

Microdissection of Black Widow Spider Silk-producing Glands

Modern spiders spin high-performance silk fibers with a broad range of biological functions, including locomotion, prey capture and protection of developing offspring 1,2. Spiders accomplish these tasks by spinning several distinct fiber types that have diverse mechanical properties. Such specialization of fiber types has occurred through the evolution of different silk-producing glands, which function as small biofactories. These biofactories manufacture and store large quantities of silk proteins for fiber production. Through a complex series of biochemical events, these silk proteins are converted from a liquid into a solid material upon extrusion.
Mechanical studies have demonstrated that spider silks are stronger than high-tensile steel 3. Analyses to understand the relationship between the structure and function of spider silk threads have revealed that spider silk consists largely of proteins, or fibroins, that have block repeats within their protein sequences 4. Common molecular signatures that contribute to the incredible tensile strength and extensibility of spider silks are being unraveled through the analyses of translated silk cDNAs. Given the extraordinary material properties of spider silks, research labs across the globe are racing to understand and mimic the spinning process to produce synthetic silk fibers for commercial, military and industrial applications. One of the main challenges to spinning artificial spider silk in the research lab involves a complete understanding of the biochemical processes that occur during extrusion of the fibers from the silk-producing glands.
Here we present a method for the isolation of the seven different silk-producing glands from the cobweaving black widow spider, which includes the major and minor ampullate glands [manufactures dragline and scaffolding silk] 5,6, tubuliform [synthesizes egg case silk] 7,8, flagelliform [unknown function in cob-weavers], aggregate [makes glue silk], aciniform [synthesizes prey wrapping and egg case threads] 9 and pyriform [produces attachment disc silk] 10. This approach is based upon anesthetizing the spider with carbon dioxide gas, subsequent separation of the cephalothorax from the abdomen, and microdissection of the abdomen to obtain the silk-producing glands. Following the separation of the different silk-producing glands, these tissues can be used to retrieve different macromolecules for distinct biochemical analyses, including quantitative real-time PCR, northern- and western blotting, mass spectrometry (MS or MS/MS) analyses to identify new silk protein sequences, search for proteins that participate in the silk assembly pathway, or use the intact tissue for cell culture or histological experiments.

Here we describe an efficient strategy to remove the silk-producing glands from the abdomen of female black widow spiders. This procedure allows the rapid isolation of the seven distinct silk-producing glands in a highly purified fashion, an important process for investigators studying spider silk production and fiber assembly.

Mikrodissektion von Black Widow Spider Silk-produzierenden Drüsen

Modern spiders spin high-performance silk fibers with a broad range of biological functions, including locomotion, prey capture and protection of ...

Immunostaining of Dissected Zebrafish Embryonic Heart

Zebrafish embryo becomes a popular in vivo vertebrate model for studying cardiac development and human heart diseases due to its advantageous embryology and genetics 1,2. About 100-200 embryos are readily available every week from a single pair of adult fish. The transparent embryos that develop ex utero make them ideal for assessing cardiac defects 3. The expression of any gene can be manipulated via morpholino technology or RNA injection 4. Moreover, forward genetic screens have already generated a list of mutants that affect different perspectives of cardiogenesis 5. 
Whole mount immunostaining is an important technique in this animal model to reveal the expression pattern of the targeted protein to a particular tissue 6. However, high resolution images that can reveal cellular or subcellular structures have been difficult, mainly due to the physical location of the heart and the poor penetration of the antibodies. 
 Here, we present a method to address these bottlenecks by dissecting heart first and then conducting the staining process on the surface of a microscope slide. To prevent the loss of small heart samples and to facilitate solution handling, we restricted the heart samples within a circle on the surface of the microscope slides drawn by an immEdge pen. After the staining, the fluorescence signals can be directly observed by a compound microscope. 
Our new method significantly improves the penetration for antibodies, since a heart from an embryonic fish only consists of few cell layers. High quality images from intact hearts can be obtained within a much reduced procession time for zebrafish embryos aged from day 2 to day 6. Our method can be potentially extended to stain other organs dissected from either zebrafish or other small animals.

A rapid way to conduct immunostaining of zebrafish embryonic heart is described. Compared to the whole mount immunostaining approach, this method dramatically increases the penetration of the antibodies, which allows obtaining high resolution images that reveal cellular/subcellular structures in the heart within a much reduced processing time.

Immunfärbung von Dissected Zebrafisch embryonale Herz

Zebrafish embryo becomes a popular in vivo vertebrate model for studying cardiac development and human heart diseases due to its advantageous embryology ...

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal neurons. In contrast, the adult zebrafish retina possesses the robust ability to spontaneously regenerate any neuronal class that is lost in a variety of different retinal damage models, including retinal puncture, chemical ablation, concentrated high temperature, and intense light treatment 1-8. Our lab extensively characterized regeneration of photoreceptors following constant intense light treatment and inner retinal neurons after intravitreal ouabain injection 2, 5, 9. In all cases, resident M&uuml;ller glia re-enter the cell cycle to produce neuronal progenitors, which continue to proliferate and migrate to the proper retinal layer, where they differentiate into the deficient neurons. 
	We characterized five different stages during regeneration of the light-damaged retina that were highlighted by specific cellular responses. We identified several differentially expressed genes at each stage of retinal regeneration by mRNA microarray analysis 10. Many of these genes are also critical for ocular development. To test the role of each candidate gene/protein during retinal regeneration, we needed to develop a method to conditionally limit the expression of a candidate protein only at times during regeneration of the adult retina. 
	Morpholino oligos are widely used to study loss of function of specific proteins during the development of zebrafish, Xenopus, chick, mouse, and tumors in human xenografts 11-14. These modified oligos basepair with complementary RNA sequence to either block the splicing or translation of the target RNA. Morpholinos are stable in the cell and can eliminate or "knockdown" protein expression for three to five days 12. 
	Here, we describe a method to efficiently knockdown target protein expression in the adult zebrafish retina. This method employs lissamine-tagged antisense morpholinos that are injected into the vitreous of the adult zebrafish eye. Using electrode forceps, the morpholino is then electroporated into all the cell types of the dorsal and central retina. Lissamine provides the charge on the morpholino for electroporation and can be visualized to assess the presence of the morpholino in the retinal cells. 
	Conditional knockdown in the retina can be used to examine the role of specific proteins at different times during regeneration. Additionally, this approach can be used to study the role of specific proteins in the undamaged retina, in such processes as visual transduction and visual processing in second order neurons.

In vivo Electroporation of Morpholinos into the Adult Zebrafish Retina

A method to conditionally knockdown a target protein&#x2019;s expression in the adult zebrafish retina is described, which involves intravitreally injecting antisense morpholinos and electroporating them into the retina. The resulting protein is knocked down for several days, which allows testing the protein&#x2019;s role in the regenerating or intact retina.

In-vivo-Elektroporation von Morpholinos in die Adult Zebrafisch Retina

Many devastating inherited eye diseases result in progressive and irreversible blindness because humans cannot regenerate dying or diseased retinal ...

A System for ex vivo Culturing of Embryonic Pancreas

The pancreas controls vital functions of our body, including the production of digestive enzymes and regulation of blood sugar levels1. Although in the past decade many studies have contributed to a solid foundation for understanding pancreatic organogenesis, important gaps persist in our knowledge of early pancreas formation2. A complete understanding of these early events will provide insight into the development of this organ, but also into incurable diseases that target the pancreas, such as diabetes or pancreatic cancer. Finally, this information will generate a blueprint for developing cell-replacement therapies in the context of diabetes.
 During embryogenesis, the pancreas originates from distinct embryonic outgrowths of the dorsal and ventral foregut endoderm at embryonic day (E) 9.5 in the mouse embryo3,4. Both outgrowths evaginate into the surrounding mesenchyme as solid epithelial buds, which undergo proliferation, branching and differentiation to generate a fully mature organ2,5,6. Recent evidences have suggested that growth and differentiation of pancreatic cell lineages, including the insulin-producing &beta;-cells, depends on proper tissue-architecture, epithelial remodeling and cell positioning within the branching pancreatic epithelium7,8. However, how branching morphogenesis occurs and is coordinated with proliferation and differentiation in the pancreas is largely unknown. This is in part due to the fact that current knowledge about these developmental processes has relied almost exclusively on analysis of fixed specimens, while morphogenetic events are highly dynamic.
 Here, we report a method for dissecting and culturing mouse embryonic pancreatic buds ex vivo on glass bottom dishes, which allow direct visualization of the developing pancreas (Figure 1). This culture system is ideally devised for confocal laser scanning microscopy and, in particular, live-cell imaging. Pancreatic explants can be prepared not only from wild-type mouse embryos, but also from genetically engineered mouse strains (e.g. transgenic or knockout), allowing real-time studies of mutant phenotypes. Moreover, this ex vivo culture system is valuable to study the effects of chemical compounds on pancreatic development, enabling to obtain quantitative data about proliferation and growth, elongation, branching, tubulogenesis and differentiation. In conclusion, the development of an ex vivo pancreatic explant culture method combined with high-resolution imaging provides a strong platform for observing morphogenetic and differentiation events as they occur within the developing mouse embryo.

A System for ex vivo Culturing of Embryonic Pancreas

Here, we describe a method for isolation, culture and manipulation of mouse embryonic pancreas. This represents an excellent ex vivo system for studying various aspects of pancreatic development, including morphogenesis, differentiation and growth. Pancreatic bud explants can be cultured for several days and used in a range of different applications, including whole-mount immunofluorescence and live imaging.

Ein System für<em&gt; Ex vivo</em&gt; Kultivierung von embryonalen Pankreas

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

Laser-inflicted Injury of Zebrafish Embryonic Skeletal Muscle

Various experimental approaches have been used in mouse to induce muscle injury with the aim to study muscle regeneration, including myotoxin injections (bupivacaine, cardiotoxin or notexin), muscle transplantations (denervation-devascularization induced regeneration), intensive exercise, but also murine muscular dystrophy models such as the mdx mouse (for a review of these approaches see 1). In zebrafish, genetic approaches include mutants that exhibit muscular dystrophy phenotypes (such as runzel2 or sapje3) and antisense oligonucleotide morpholinos that block the expression of dystrophy-associated genes4. Besides, chemical approaches are also possible, e.g. with Galanthamine, a chemical compound inhibiting acetylcholinesterase, thereby resulting in hypercontraction, which eventually leads to muscular dystrophy5. However, genetic and pharmacological approaches generally affect all muscles within an individual, whereas the extent of physically inflicted injuries are more easily controlled spatially and temporally1. Localized physical injury allows the assessment of contralateral muscle as an internal control. Indeed, we recently used laser-mediated cell ablation to study skeletal muscle regeneration in the zebrafish embryo6, while another group recently reported the use of a two-photon laser (822 nm) to damage very locally the plasma membrane of individual embryonic zebrafish muscle cells7.
Here, we report a method for using the micropoint laser (Andor Technology) for skeletal muscle cell injury in the zebrafish embryo. The micropoint laser is a high energy laser which is suitable for targeted cell ablation at a wavelength of 435 nm. The laser is connected to a microscope (in our setup, an optical microscope from Zeiss) in such a way that the microscope can be used at the same time for focusing the laser light onto the sample and for visualizing the effects of the wounding (brightfield or fluorescence). The parameters for controlling laser pulses include wavelength, intensity, and number of pulses.
Due to its transparency and external embryonic development, the zebrafish embryo is highly amenable for both laser-induced injury and for studying the subsequent recovery. Between 1 and 2 days post-fertilization, somitic skeletal muscle cells progressively undergo maturation from anterior to posterior due to the progression of somitogenesis from the trunk to the tail8, 9. At these stages, embryos spontaneously twitch and initiate swimming. The zebrafish has recently been recognized as an important vertebrate model organism for the study of tissue regeneration, as many types of tissues (cardiac, neuronal, vascular etc.) can be regenerated after injury in the adult zebrafish10, 11.

The method presented here comprises the precise injury of live zebrafish embryos with high-energy laser pulses and the subsequent analysis of these injuries and their recovery with time. We also show how genetically labeled single or groups of skeletal muscle cells can be tracked during and after laser light induced damage.

Laser-Schädigung der Zebrafisch Embryonale Skeletal Muscle

Various experimental approaches have been used in mouse to induce muscle injury with the aim to study muscle regeneration, including myotoxin injections ...