Name: use of immunolabeling to analyze stable, dynamic, and nascent microtubules in the zebrafish embryo
Uploaded: 2017-09-20T13:00:00
Description: Watch this Scientific Journal Video about Use of Immunolabeling to Analyze Stable, Dynamic, and Nascent Microtubules in the Zebrafish Embryo at JoVE.com

The confocal microscope was purchased with funds from the U.S. National Science Foundation (NSF), grant #DBI-0722569. The research was supported by the U.S. National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS) grant #GM085290 and U.S. Department of Defense (DOD) grant #W81XWH-16-1-0466 awarded to R.M. Brewster. E. Vital was supported by a grant to UMBC from the Howard Hughes Medical Institute through the Pre-college and Undergraduate Science Education Program, grant #52008090. S.P. Brown was supported by a U.S. Department of Education GAANN Fellowship, a Meyerhoff Graduate Fellowship funded by NIH/NIGMS grant #GM055036, and a Research Assistantship funded by the U.S. DOD grant #W81XWH-16-1-0466.

Ethics Statement: The procedures described below follow the University of Maryland Baltimore County animal care guidelines.
1. Analysis of Stable and Dynamic MTs Using Immunolabeling (Protocol 1)
<ol>
	<li>Manual dechorionation of embryos prior to fixation
	<ol>
		<li>Obtain freshly spawned embryos by pouring off excess system water and then collecting remaining embryos into a plastic Petri dish (refer to Table of Materials).</li>
		<li>Remove any debris fro...

<ol>
	<li>Akhmanova, A., Steinmetz, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+the+ends:+a+dynamic+protein+network+controls+the+fate+of+microtubule+tips.">Tracking the ends: a dynamic protein network controls the fate of microtubule tips.</a> Nat Rev Mol Cell Biol. 9 (4), 309-322 (2008).</li><li>Conde, C., C&#225;ceres, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule+assembly,+organization+and+dynamics+in+axons+and+dendrites.">Microtubule assembly, organization and dynamics in axons and dendrites.</a> Nat Rev Neurosci. 10 (5), 319-332 (2009).</li><li>Kaverina, I., Straube, A. <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+cell+migration+by+dynamic+microtubules.">Regulation of cell migration by dynamic microtubules.</a> Semin Cell Dev Biol. 22 (9), 968-974 (2011).</li><li>Kollman, J. M., Merdes, A., Mourey, L., Agard, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule+nucleation+by+&#947;-tubulin+complexes.">Microtubule nucleation by &#947;-tubulin complexes.</a> Nat Rev Mol Cell Biol. 12 (11), 709-721 (2011).</li><li>Howard, J., Hyman, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth,+fluctuation+and+switching+at+microtubule+plus+ends.">Growth, fluctuation and switching at microtubule plus ends.</a> Nat Rev Mol Cell Biol. 10 (8), 569-574 (2009).</li><li>Schulze, E., Kirschner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+and+stable+populations+of+microtubules+in+cells.">Dynamic and stable populations of microtubules in cells.</a> J Cell Biol. 104 (2), 277-288 (1987).</li><li>Gundersen, G. G., Kalnoski, M. H., Bulinski, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+populations+of+microtubules:+Tyrosinated+and+nontyrosinated+alpha+tubulin+are+distributed+differently+in+vivo.">Distinct populations of microtubules: Tyrosinated and nontyrosinated alpha tubulin are distributed differently in vivo.</a> Cell. 38 (3), 779-789 (1984).</li><li>Li, R., Gundersen, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+polymer+polarity:+how+the+cytoskeleton+builds+a+polarized+cell.">Beyond polymer polarity: how the cytoskeleton builds a polarized cell.</a> Nat Rev Mol Cell Biol. 9 (11), 860-873 (2008).</li><li>Asakawa, K., Kawakami, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transgenic+zebrafish+for+monitoring+in+vivo+microtubule+structures.">A transgenic zebrafish for monitoring in vivo microtubule structures.</a> Dev Dyn Off Publ Am Assoc Anat. 239 (10), 2695-2699 (2010).</li><li>W&#252;hr, M., Tan, E. S., Parker, S. K., Detrich, H. W., Mitchison, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+for+cleavage+plane+determination+in+early+amphibian+and+fish+embryos.">A model for cleavage plane determination in early amphibian and fish embryos.</a> Curr Biol CB. 20 (22), 2040-2045 (2010).</li><li>Tran, L. D., Hino, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+microtubules+at+the+vegetal+cortex+predict+the+embryonic+axis+in+zebrafish.">Dynamic microtubules at the vegetal cortex predict the embryonic axis in zebrafish.</a> Development. 139 (19), 3644-3652 (2012).</li><li>Butler, R., Wood, J. D., Landers, J. A., Cunliffe, V. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+and+chemical+modulation+of+spastin-dependent+axon+outgrowth+in+zebrafish+embryos+indicates+a+role+for+impaired+microtubule+dynamics+in+hereditary+spastic+paraplegia.">Genetic and chemical modulation of spastin-dependent axon outgrowth in zebrafish embryos indicates a role for impaired microtubule dynamics in hereditary spastic paraplegia.</a> Dis Model Mech. 3 (11-12), 743-751 (2010).</li><li>Yoo, S. K., Lam, P. -. Y., Eichelberg, M. R., Zasadil, L., Bement, W. M., Huttenlocher, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+microtubules+in+neutrophil+polarity+and+migration+in+live+zebrafish.">The role of microtubules in neutrophil polarity and migration in live zebrafish.</a> J Cell Sci. 125 (23), 5702-5710 (2012).</li><li>Andersen, E. F., Halloran, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Centrosome+movements+in+vivo+correlate+with+specific+neurite+formation+downstream+of+LIM+homeodomain+transcription+factor+activity.">Centrosome movements in vivo correlate with specific neurite formation downstream of LIM homeodomain transcription factor activity.</a> Development. 139 (19), 3590-3599 (2012).</li><li>Lee, S. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+regulation+of+the+microtubule+and+actin+cytoskeleton+in+zebrafish+epiboly.">Dynamic regulation of the microtubule and actin cytoskeleton in zebrafish epiboly.</a> Biochem Biophys Res Commun. 452 (1), 1-7 (2014).</li><li>Bulinski, J. C., Gundersen, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stabilization+and+post-translational+modification+of+microtubules+during+cellular+morphogenesis.">Stabilization and post-translational modification of microtubules during cellular morphogenesis.</a> BioEssays. 13 (6), 285-293 (1991).</li><li>Magiera, M. M., Janke, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+16+-+Investigating+Tubulin+Posttranslational+Modifications+with+Specific+Antibodies.">Chapter 16 - Investigating Tubulin Posttranslational Modifications with Specific Antibodies.</a> Methods Cell Biol. 115, 247-267 (2013).</li><li>Hong, E., Jayachandran, P., Brewster, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+polarity+protein+Pard3+is+required+for+centrosome+positioning+during+neurulation.">The polarity protein Pard3 is required for centrosome positioning during neurulation.</a> Dev Biol. 341 (2), 335-345 (2010).</li><li>Westermann, S., Weber, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Post-translational+modifications+regulate+microtubule+function.">Post-translational modifications regulate microtubule function.</a> Nat Rev Mol Cell Biol. 4 (12), 938-948 (2003).</li><li>Jayachandran, P., Olmo, V. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule-associated+protein+1b+is+required+for+shaping+the+neural+tube.">Microtubule-associated protein 1b is required for shaping the neural tube.</a> Neural Develop. 11, 1 (2016).</li><li>Nam, S. -. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+Tau,+a+microtubule+associated+protein,+in+Drosophila+photoreceptor+morphogenesis.">Role of Tau, a microtubule associated protein, in Drosophila photoreceptor morphogenesis.</a> Genes N Y N 2000. 54 (11), 553-561 (2016).</li><li>Abal, M., Piel, M., Bouckson-Castaing, V., Mogensen, M., Sibarita, J. -. B., Bornens, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule+release+from+the+centrosome+in+migrating+cells.">Microtubule release from the centrosome in migrating cells.</a> J Cell Biol. 159 (5), 731-737 (2002).</li><li>Delgehyr, N., Sillibourne, J., Bornens, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule+nucleation+and+anchoring+at+the+centrosome+are+independent+processes+linked+by+ninein+function.">Microtubule nucleation and anchoring at the centrosome are independent processes linked by ninein function.</a> J Cell Sci. 118 (8), 1565-1575 (2005).</li><li>Manning, J. A., Lewis, M., Koblar, S. A., Kumar, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+essential+function+for+the+centrosomal+protein+NEDD1+in+zebrafish+development.">An essential function for the centrosomal protein NEDD1 in zebrafish development.</a> Cell Death Differ. 17 (8), 1302-1314 (2010).</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 Off Publ Am Assoc Anat. 203 (3), 253-310 (1995).</li><li>Beck, A. P., Watt, R. 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Z-functions - ImageJ Available from: <a target="_blank" href="https://imagej.net/Z-functions">https://imagej.net/Z-functions</a> (2017)</li></ol>

There are currently many methods for imaging MT dynamics in early zebrafish development, ranging from live imaging of tagged molecules to immunolabeling of fixed tissue11,12,13,14. Although MTs in a single cell can exist in either dynamic or stable states, epithelialization is a process in which MTs are progressively stabilized over time. Using markers for stable and dynamic MTs offers a way to...

Microtubules (MTs) are polymers of &#945;- and &#946;-tubulin that assemble into linear protofilaments, several of which combine to form a hollow tube1,2. MTs are polarized structures, with fast-growing plus ends and slow-growing minus ends that are anchored at the centrosome or other microtubule-organizing center (MTOC)3. De novo MT formation is initiated by nucleation at the &#947;-tubulin ring complex (&#947;-TURC), which provides a template for MT assembly4. In any given cell, two populations of MTs can be distinguished that turn over at different rates. Dynamic MTs explore their cellular environment by switching between phases of growth and shrinkage in a process known as dynamic instability5. Unlike dynamic MTs, stable MTs are non-growing and have a longer half-life than dynamic MTs6.

Decades of research in cell biology has provided a sophisticated array of tools to study MT structure and function and resulted in a large body of knowledge on these cytoskeletal elements. For instance, MTs play a central role in the establishment and maintenance of cell polarity, which is attributable not only to their intrinsic polarity, but also to the differential subcellular distribution of stable versus dynamic MTs7,8. In contrast, far less is understood about MT architecture and function in more complex three-dimensional (3-D) environments, such as the vertebrate embryo, in part due to the challenge of imaging the MT cytoskeleton at high resolution. Despite this limitation, the recent generation of GFP-expressing transgenic lines that label MTs or transient expression of fluorescently-tagged MT markers has increased our understanding of the dynamic changes that MTs undergo and their cellular and developmental role in the zebrafish embryo. The entire MT network can be imaged in transgenic lines in which tubulin is either directly labeled9 or tubulin polymers are indirectly labeled using MT-associated proteins Doublecortin-like-kinase (Dclk) or Ensconsin (EMTB)10,11. Other lines (and constructs) have been generated that enable assessment of MT intrinsic polarity by specifically labeling MT plus ends or centrosome-anchored minus ends11,12,13,14. The power of these tools lies in the ability to study MT dynamics in live, developing organisms. Such studies have revealed, for example, the spatial and dynamic distribution of MTs in specific cell populations, the orientation of mitotic spindles in tissues undergoing morphogenesis (an indicator of the plane of cell division), the polarity of the MT polymer as it relates to processes such as cell elongation and migration, and MT growth rate determined by comet speed9,13,15. The limitation of these tools is that they do not readily discriminate between stable and dynamic MT populations.

Drawing from the rich cell biology literature, immunolabeling methods to image stable and dynamic MTs in the zebrafish embryo are described here, which are complementary to the use of transgenic lines. The widespread use of such immunolabeling methods in the zebrafish has been somewhat hampered by the difficulty in preserving MT integrity during the fixation procedure. Protocol 1 outlines an optimized method for immunolabeling total, dynamic, and stable MTs in cross sections of the developing zebrafish hindbrain. Furthermore, a straightforward method using commercially available software is described to quantify these MT populations. Stable MTs are distinguished from dynamic MTs based on several post-translational modifications of &#945;-tubulin, such as acetylation and detyrosination, which accumulate on stable MTs over time16,17. In the zebrafish embryo, acetylation occurs on ciliary and axonal MTs but not on stable interphase MTs18, limiting the usefulness of this marker to a subset of stabilized MTs. In contrast, detyrosination appears to occur on all stable MTs in the zebrafish embryo18. This post-translational modification exposes the carboxy-terminal glutamic acid of &#945;-tubulin (detyrosinated tubulin)18 and can be detected using anti-Glu-tubulin19. Although detyrosination occurs preferentially on stable MTs, experimental evidence indicates that this post-translational modification is a result of, rather than a cause of, MT stability16. The reciprocal MT population, composed of dynamic MTs, is distinguished using an antibody, anti-Tyr-tubulin, that specifically recognizes the tyrosinated form of &#945;-tubulin19. Following immunolabeling with these markers and confocal imaging, the quantitative analysis of MTs (length, number, and relative abundance) can be performed in defined regions of the developing neural tube. A streamlined method is provided here for performing this analysis using 3-D image-processing software. This method can be applied to address questions regarding morphogenesis and the establishment or maturation of cell polarity20. Indeed, the elaboration of polarized arrays of stable MTs accompanies many developmental events, including photoreceptor morphogenesis21, epithelialization of cells in the developing neural tube18 and axon formation8.

Protocol 2 describes an in vivo adaptation of a cell biology assay to analyze MTs during their assembly phase (nucleation/anchorage and growth)22,23. Nascent MTs are nucleated at the centrosome and subsequently anchored to subdistal appendages of the mother centriole23. A method to analyze nascent MT regrowth following depolymerization is described. This protocol provides details on the nocodazole treatment to depolymerize MTs, the drug washout procedure and the post-treatment recovery period. MT re-growth is monitored at regular intervals post washout by immunolabeling with markers for total MTs (anti &#946;-tubulin) alongside markers for the centrosome (anti &#947;-tubulin) and nucleus (4&#39;,6-diamidino-2-phenylindole (DAPI)), according to the general procedures described in Protocol 1. The MT depolymerization step of this protocol is essential as it enables assessment of de novo MT growth rather than extension of preexisting MTs. This technique is therefore distinct from other published procedures to measure MT growth rates (in absence of depolymerization) by using a plus tip marker such as end binding protein 3 fused to green fluorescent protein (EB3-GFP), as shown in Tran et al., 201211. Furthermore, this assay is particularly useful for analyzing embryos defective in de novo MT assembly, such as the previously reported NEDD1 mutants in which recruitment of &#947;-tubulin to the centrosome is impaired, resulting in incomplete neural tube formation and neuronal defects24.

<table border="0" cellpadding="0" cellspacing="0" width="916">
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	<tbody>
		<tr height="140">
			<td height="140" style="height:140px;width:207px;">Low Melting Point Agarose</td>
			<td style="width:177px;">IBI scientific</td>
			<td style="width:159px;">IB70050</td>
			<td style="width:373px;">Only used for embedding. 
			 
			Prepare 4% LMP agarose 
			by heating a solution of&#160; 4 grams LMP agarose per 100 ml 1X TBS in a microwave 
			until polymerized. Keep warm on a 50 &#730;C hot plate with the cap secured</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:207px;">Agarose</td>
			<td style="width:177px;"></td>
			<td style="width:159px;"></td>
			<td style="width:373px;">Used to treat petridishes.&#160;&#160; Prepare 1% agarose 
			by heating a solution of&#160; 1 gram agarose per 100 ml 1X embryo medium in a microwave 
			until polymerized.&#160;</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:207px;">Nocodazole</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">487928-10MG</td>
			<td style="width:373px;">Make stock by dissolving entire bottle of powder in distilled water and aliquoting into 500ul aliquots.&#160; Store at -20 &#730;C.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">8% Formaldehyde</td>
			<td style="width:177px;">Electron Microscopy Sciences</td>
			<td style="width:159px;">157-8-100</td>
			<td style="width:373px;">Aliquot and store at -20 &#730;C.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Kpipes</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">P7643</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">NaCl</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">S7653</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Tris-HCl</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">T3253-500G</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">KCl</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">P9333-500G</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">CaCl2&#183;2H2O</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">C5080</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">NP-40</td>
			<td style="width:177px;">American Bioanalyticals</td>
			<td style="width:159px;">AB01424</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">EGTA</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">E3889-25G</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">MgCl2</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">M2670-500G</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Normal Goat Serum</td>
			<td style="width:177px;">Millipore</td>
			<td style="width:159px;">S26-100ml</td>
			<td style="width:373px;">Aliquot and store at -20 &#730;C.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Bovine serum albumin (BSA)</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">BP1605</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Triton-x</td>
			<td style="width:177px;">American Bioanalyticals</td>
			<td style="width:159px;">AB02025</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:207px;">Pronase E (non-specific Protease from Streptomyces griseus)</td>
			<td style="width:177px;">Sigma</td>
			<td style="width:159px;">P5147-1G</td>
			<td style="width:373px;">make stock solution by diluting 10mg per ml of ddH2O. Aliquot in 1ml aliquots and store at -20 &#730;C.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Anti-Fade mounting medium</td>
			<td style="width:177px;">Invitrogen</td>
			<td style="width:159px;">P10144</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:207px;">DAPI</td>
			<td style="width:177px;">Invitrogen</td>
			<td style="width:159px;">D1306</td>
			<td style="width:373px;">Prepare 50 ml DAPI solution by first combining 1 &#181;l DAPI stock&#160; with 1 ml sterile water and then adding the DAPI/water mix to 49 ml 1X TBS; store in foil at 4 &#730;C for months.</td>
		</tr>
		<tr height="51">
			<td height="51" style="height:51px;width:207px;">Mouse anti-&#946;-tubulin</td>
			<td style="width:177px;">Developmental studies Hybridoma Bank</td>
			<td style="width:159px;">E7</td>
			<td style="width:373px;">1/200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Rabbit anti-&#947;-tubulin</td>
			<td style="width:177px;">Genetex</td>
			<td style="width:159px;">GTX113286</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Rabbit anti-&#945;-tubulin</td>
			<td style="width:177px;">Genetex</td>
			<td style="width:159px;">GTX108784</td>
			<td style="width:373px;">1/1000*</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Rabbit anti-detyrosinated-tubulin</td>
			<td style="width:177px;">Millipore</td>
			<td style="width:159px;">AB3201</td>
			<td style="width:373px;">1/200-1/1000*&#160; Titrate antibody with first use of new lot.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Rabbit anti-tyrosinated-tubulin</td>
			<td style="width:177px;">Millipore</td>
			<td style="width:159px;">ABT171</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Mouse anti-centrin</td>
			<td style="width:177px;">Millipore</td>
			<td style="width:159px;">04-1624</td>
			<td style="width:373px;">1/1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Goat 488 anti-rabbit</td>
			<td style="width:177px;">Thermofisher</td>
			<td style="width:159px;">A11008</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Goat 594 anti-rabbit</td>
			<td style="width:177px;">Thermofisher</td>
			<td style="width:159px;">A11012</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Goat 594 anti-mouse</td>
			<td style="width:177px;">Thermofisher</td>
			<td style="width:159px;">A11005</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Goat 488 anti-mouse</td>
			<td style="width:177px;">Thermofisher</td>
			<td style="width:159px;">A11001</td>
			<td style="width:373px;">1/500</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Vibratome</td>
			<td style="width:177px;">Vibratome</td>
			<td style="width:159px;">1500</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Forceps</td>
			<td style="width:177px;">World Precision Instruments</td>
			<td style="width:159px;">555227F</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">100 mm petri dish</td>
			<td style="width:177px;">Cell treat</td>
			<td style="width:159px;">229693</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">35 mm petri dish</td>
			<td style="width:177px;">Cell treat</td>
			<td style="width:159px;">229638</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">50 ml falcon tube</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">14-432-22</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Woven nylon mesh 70 um</td>
			<td style="width:177px;">Amazon.com</td>
			<td style="width:159px;">B0043D1SZG&#160;</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Micropipette</td>
			<td style="width:177px;">Gilson</td>
			<td style="width:159px;">F123602</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Glass pipette</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">NC-999363-9</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Aquarium sealant</td>
			<td style="width:177px;">Amazon.com, by MarineLand</td>
			<td style="width:159px;">Silicone Sealer 1 oz (Tube)&#160;</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Ring stand</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">14-675BO</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Microbore PTFE Tubing, 0.022&#34;ID</td>
			<td style="width:177px;">Cole-Parmer</td>
			<td style="width:159px;">WU-06417-21</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Modeling clay</td>
			<td style="width:177px;">Amazon.com</td>
			<td style="width:159px;">Sargent Art 22-4000</td>
			<td style="width:373px;">Any wax or oil based non-toxic modeling clay will suffice</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Clamp</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">02-215-466</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">60ml syringe</td>
			<td style="width:177px;">Fisher</td>
			<td style="width:159px;">14-820-11</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="180">
			<td height="180" style="height:180px;width:207px;">Embryo medium (E3)</td>
			<td style="width:177px;"></td>
			<td style="width:159px;"></td>
			<td style="width:373px;">34.8 g NaCl 
			1.6 g KCl 
			5.8 g CaCl2&#183;2H2O 
			9.78 g MgCl2&#183;6H2O 
			 
			To prepare a 60X stock, dissolve the ingredients in H2O, to a final volume of 2 L. Adjust the pH to 7.2 with NaOH. Autoclave. To prepare 1X medium, dilute 16.5 mL of the 60X stock to 1 L.&#160;</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:207px;">Blocking Solution</td>
			<td style="width:177px;"></td>
			<td style="width:159px;"></td>
			<td style="width:373px;">50 ml TBS-NP-40 
			2.5 ml normal goat serum 
			1 g BSA 
			625 &#181;l Triton-X</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:207px;">TBS-NP-40 (pH 7.6)</td>
			<td style="width:177px;"></td>
			<td style="width:159px;"></td>
			<td style="width:373px;">155 mM NaCl 
			10 mM Tris HCl 
			0.1% NP-40</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:207px;">2x MAB (pH6.4)</td>
			<td style="width:177px;"></td>
			<td style="width:159px;"></td>
			<td style="width:373px;">160 mM KPIPES 
			10 mM EGTA 
			2 mM MgCl2</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:207px;">Commercial 3-D Image processing Software</td>
			<td style="width:177px;">PerkinElmer</td>
			<td style="width:159px;">Volocity (V 6.2)</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Dry block heater&#160;</td>
			<td style="width:177px;">VWR</td>
			<td style="width:159px;">12621-108</td>
			<td style="width:373px;">Used as a hot plate to melt agarose in Protocol 1.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Dissecting Microscope</td>
			<td style="width:177px;">Leica</td>
			<td style="width:159px;">MZ12</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Confocal Microscope</td>
			<td style="width:177px;">Leica</td>
			<td style="width:159px;">SP5</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:207px;">Flat embedding mold</td>
			<td style="width:177px;">emsdiasum.com</td>
			<td style="width:159px;">BEEM 70904-01</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:207px;">Public domain image processing software</td>
			<td style="width:177px;">NIH</td>
			<td style="width:159px;">ImageJ (V 1.5)</td>
			<td style="width:373px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
			<td style="width:532px;">* Success varies by lot number</td>
		</tr>
	</tbody>
</table>

use of immunolabeling to analyze stable, dynamic, and nascent microtubules in the zebrafish embryo

Microtubules (MTs) are dynamic and fragile structures that are challenging to image in vivo, particularly in vertebrate embryos. Immunolabeling methods are described here to analyze distinct populations of MTs in the developing neural tube of the zebrafish embryo. While the focus is on neural tissue, this methodology is broadly applicable to other tissues. The procedures are optimized for early to mid-somitogenesis-stage embryos (1 somite to 12 somites), however they can be adapted to a range of other stages with relatively minor adjustments. The first protocol provides a method to assess the spatial distribution of stable and dynamic MTs and perform a quantitative analysis of these populations with image-processing software. This approach complements existing tools to image microtubule dynamics and distribution in real-time, using transgenic lines or transient expression of tagged constructs. Indeed, such tools are very useful, however they do not readily distinguish between dynamic and stable MTs. The ability to image and analyze these distinct microtubule populations has important implications for understanding mechanisms underlying cell polarization and morphogenesis. The second protocol outlines a technique to analyze nascent MTs specifically. This is accomplished by capturing the de novo growth properties of MTs over time, following microtubule depolymerization with the drug nocodazole and a recovery period after drug washout. This technique has not yet been applied to the study of MTs in zebrafish embryos, but is a valuable assay for investigating the in vivo function of proteins implicated in microtubule assembly.

Analysis of stable and dynamic MTs using immunolabeling 
In Protocol 1, the distribution of MT sub-populations during early (neural keel) and late (neural rod) stages of neural tube development is revealed, using Glu-tubulin and Tyr-tubulin as markers for stable and dynamic MTs, respectively. Dynamic MTs predominate in the hindbrain at the neural keel stage (4-5 somites) (Figure 2A-D). As the keel develo...

Watch this Scientific Journal Video about Use of Immunolabeling to Analyze Stable, Dynamic, and Nascent Microtubules in the Zebrafish Embryo at JoVE.com

Use of Immunolabeling to Analyze Stable, Dynamic, and Nascent Microtubules in the Zebrafish Embryo

Immunolabeling methods to analyze distinct populations of microtubules in the developing zebrafish brain are described here, which are broadly applicable to other tissues. The first protocol outlines an optimized method for immunolabeling stable and dynamic microtubules. The second protocol provides a method to image and quantify nascent microtubules specifically.

Microtubules (MTs) are dynamic and fragile structures that are challenging to image in vivo, particularly in vertebrate embryos. Immunolabeling methods ...

The overall goal of these labeling procedures is to image and quantify stable, dynamic and nascent microtubules in the developing zebrafish embryo. This method can help answer key questions in the field of developmental neurobiology such as, how microtubules contribute to the establishment of cell polarity. The main advantage of this technique is that it optimizes the detection and quantification of distinct microtubule populations in situ.Generally, individuals new to this method will struggle because of the difficulties in maintaining microtubule integrity. After de-chlorinating staged zebrafish embryos according to the text protocol, transfer them to 1, 5 milliliter centrifuge tubes, removing as much medium as possible. Add one milliliter of 4%PFA in microtubule assembly buffer or MAB, to fix the embryos at 28.5 degree celsius for five minutes.Then use a pipette to aspirate the fixative and replace it with one milliliter of fresh fixative. Incubate the sampels on a rocker at room temperature for three hours. Aspirate the fixative and add one milliliter of TBS NP-40 buffer.Gently agitate the embryos on a rocker for five minutes. Repeat the wash two more times. Then, after replacing the buffer with one milliliter of fresh TBS NP-40, store the embryos at four degree celsius for no more than seven days.After de-yolking and embedding embryos in agarose according to the text protocol, put the sectioning dish filled with TBS NP-40, use a vibratome to generate 40 micrometers sections of the tallest access of the agarose embedded embryos. Use fine forceps to transfer sections of interest to 500 microliters of TBS NP-40 in a 24 well plate. Remove the buffer, and add 500 microliters of blocking solution.Then rock the sections at room temperature for at least one hour. Replace the blocking solution with 300 microliters of primary antibodies diluted in blocking buffer and incubate the samples on a rocker at four degree celsius for 36 to 72 hours. Use 600 microliters of TBS NP-40 to wash the samples twice.Placing them on a rocker at room temperature for 30 minutes each. Add 300 microliters of fluorophore conjugated secondary antibodies diluted in blocking buffer to the sections and incubate them in the dark on a rocker at four degree celsius for 16 to 24 hours. Then wash the samples twice as just demonstrated.Next, add 500 microliters of DAPI solution to the embryos and incubate them at room temperature for 30 minutes. Then use TBS NP-40 to wash the samples three times at room temperature for five minutes. Following the washes, place a drop of mounting medium with anti-fade agent on the center of a dust-free slide.Use fine forceps to transfer sections to the mounting medium droplet. Then place a dust-free cover slip on top of the sample. Store slides wrapped in foil, in a dry, dark and cool place until imaging is performed.Using the details outlined in the text protocol, capture z stack confocal images with channel settings for the selected secondary antibody fluorophores and save the image files. With 3D analysis software such as, Image J, open the data file copy. Create a merged image by overlaying the channels of interest by selecting image, color, merge channels.Select the 594 nanometer, 488 nanometer and DAPI channels to be false colored red, green and blue respectively. Check, create composite and select, okay. Visualize the merged z stack as a single 2D image by performing a maximum intensity projection of the z stack using images, stack, z project.Enter the starting and ending positions of the inner best z planes as the start slide and stop slice respectively. Select max intensity as the projection type and click okay. In the 3D analysis software, select, create library and provide a descriptive name for the image library.Click, create and drag raw image files into the library. Next, select a file to analyze. Then, from the view menu, choose, extended focus to display the channel merged image in the main window.Select, the free hand ROI tool and outline the region of interest to be analyzed. Select the actions tab, followed by, crop to selection to crop the image. Then save the cropped image file under a new name.Next, click the measurements tab to create the protocol for filtering specific objects relevant to the 3D analysis. Then drag, find objects to the protocol window and rename the first protocol, DAPI. Select the beta tubulin channel in the drop down menu.Then drag the following settings to the beta tubulin protocol and place them below find objects in the following order. Fill holes and objects, separate touching objects, exclude objects by size and exclude not touching ROIs. Now, select, measure at the bottom of each protocol.Then for all channels except DAPI, choose intensity and volume measurement and skeletal length for all tubulin labeling. Draw an ROI around the region to be measured. Under the summary tab, observe the measurements after the software processes the region.Then copy the data and save them to a workable spreadsheet as shown here. To construct a multi-well flow through apparatus, using a jig or a bandsaw, split a 50 milliliter centrifuge tub in half lengthwise. From 70 micrometer nylon mesh, cut seven semicircles with a radius of three centimeters and trim them to fit tightly into one half of the split centrifuge tube.Using aquarium safe silicon sealer, glue the semicircles into the centrifuge tube parallel to the 10 milliliter gradation markings. After allowing the device to dry for two days, rinse it by soaking it in a beaker of water for two to three hours. Line the top threaded end of the cut centrifuge tube with modeling clay, such that the height of the liquid retained in the flow through device has a depth of one quarter inch.Prepare the washout apparatus by removing the plunger from a 50 milliliter syringe and insert 12 inches of fine tubing into the tip. Push the tubing in as far as it would go and use modeling clay to seal around the joint. With embryo medium, pre wet the mesh to allow the liquid to run through the entire flow through device.Angle the device on ice so that liquid pulls in all compartments but still empties out the front where the clay brim is located. Suspend the washout apparatus on a ring stand above the flow through device on ice. Chill 200 milliliters of embryo medium on ice and pour enough into the washout apparatus to ensure that all air bubbles are cleared and that the flow rate is approximately seven milliliters per minute.Adjust the flow rate by changing the height of the syringe. After de-chlorinating embryos and preparing nocodazole according to the text protocol, use 10 milliliters of cold nocodazole working solution to exchange the embryo medium of the nocodazole treatment group. Place the petri dishes on ice for an appropriate time for the developmental stage.Then using a fire polished on milliliter glass pipette, transfer the embryos to the flow through apparatus using separate compartments for each experimental group. Start the nocodazole washout by pouring ice cold embryo medium into the top of the 50 milliliter syringe. Allow the microtubules to regrow after 20 minutes of washout at room temperature by using a fire polished one milliliter glass pipette to transfer embryos to glass petri dishes containing warm embryo medium.As soon as the embryos are transferred, start a timer. Finally, fix the control and washout embryos at one, five and 10 minutes by pipetting approximately 10 embryos into a 1.5 milliliter centrifuge tube filled with one milliliter of 4%PFA MAB fixative and fix the samples as demonstrated earlier in this video. Using glu-tubulin and tyr tubulin as markers for stable and dynamic microtubules.Dynamic microtubules are shown to pre=dominate in the hind brain at the neural kill stage. As the kill develops into the neural rod, a stage of enhanced epithelialization, qualitatively, fewer microtubules are immunoreactive with the anti tyr-tubulin antibody especially, in the ventral rod. In contrast, glu-tubulin is scattered and punctate throughout the neural kill but is enriched in the ventral neural rod along microtuble tract.Arrow heads point to specific microtubular bundles or structures where labeling is increased. The nocodazole treatment depolymerizes microtubules resulting in defused labeling. As the microtubules regrow, they extend from the centrosome.However, this may not be obvious in a single plane due to their non-planar trajectories. Nevertheless, some image analysis software is capable of measuring lengths in 3D, enabling an assessment of microtubule growth after the nocodazole washout. The mean length of microtubules appears to increase over time after the nocodazole washout in all regions of the neural tube analyzed.Once the data analysis is finished using the 3D image analysis software and quality is controlled for, useful information can be recovered from the raw data such as, average length of total microtubules and stable microtubules with the ratio of stable microtubules to total microtubules. Once mastered, this technique takes no longer than a week from start to finish. While attempting this procedure, it's important to remember to collect and process samples in a timely manner as microtubules depolymerize easily.This procedure can also be applied to the analysis of mutants. After watching this video, you should have a good understanding of how to capture distinct microtubule populations in the intact embryo.

use-immunolabeling-to-analyze-stable-dynamic-nascent-microtubules

Research

JoVE Journal

Developmental Biology

Production and Use of Lentivirus to Selectively Transduce Primary Oligodendrocyte Precursor Cells for In Vitro Myelination Assays

Myelination is a complex process that involves both neurons and the myelin forming glial cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS). We use an in vitro myelination assay, an established model for studying CNS myelination in vitro. To do this, oligodendrocyte precursor cells (OPCs) are added to the purified primary rodent dorsal root ganglion (DRG) neurons to form myelinating co-cultures. In order to specifically interrogate the roles that particular proteins expressed by oligodendrocytes exert upon myelination we have developed protocols that selectively transduce OPCs using the lentivirus overexpressing wild type, constitutively active or dominant negative proteins before being seeded onto the DRG neurons. This allows us to specifically interrogate the roles of these oligodendroglial proteins in regulating myelination. The protocols can also be applied in the study of other cell types, thus providing an approach that allows selective manipulation of proteins expressed by a desired cell type, such as oligodendrocytes for the targeted study of signaling and compensation mechanisms. In conclusion, combining the in vitro myelination assay with lentiviral infected OPCs provides a strategic tool for the analysis of molecular mechanisms involved in myelination.

Production and Use of Lentivirus to Selectively Transduce Primary Oligodendrocyte Precursor Cells for In Vitro Myelination Assays

Here we present protocols that offer a flexible and strategic foundation for virally manipulating oligodendrocyte precursor cells to overexpress proteins of interest in order to specifically interrogate their role in oligodendrocytes via the in vitro model of central nervous system myelination.

Myelination is a complex process that involves both neurons and the myelin forming glial cells, oligodendrocytes in the central nervous system (CNS) and ...

Use of the TetON System to Study Molecular Mechanisms of Zebrafish Regeneration

The zebrafish has become a very important model organism for studying vertebrate development, physiology, disease, and tissue regeneration. A thorough understanding of the molecular and cellular mechanisms involved requires experimental tools that allow for inducible, tissue-specific manipulation of gene expression or signaling pathways. Therefore, we and others have recently adapted the TetON system for use in zebrafish. The TetON system facilitates temporally and spatially-controlled gene expression and we have recently used this tool to probe for tissue-specific functions of Wnt/beta&#8211;catenin signaling during zebrafish tail fin regeneration. Here we describe the workflow for using the TetON system to achieve inducible, tissue-specific gene expression in the adult regenerating zebrafish tail fin. This includes the generation of stable transgenic TetActivator and TetResponder lines, transgene induction and techniques for verification of tissue-specific gene expression in the fin regenerate. Thus, this protocol serves as blueprint for setting up a functional TetON system in zebrafish and its subsequent use, in particular for studying fin regeneration.

Here we outline the workflow for using the TetON system to achieve tissue-specific gene expression in the adult regenerating zebrafish tail fin.

The zebrafish has become a very important model organism for studying vertebrate development, physiology, disease, and tissue regeneration. A thorough ...

Microbead Implantation in the Zebrafish Embryo

The zebrafish has emerged as a valuable genetic model system for the study of developmental biology and disease. Zebrafish share a high degree of genomic conservation, as well as similarities in cellular, molecular, and physiological processes, with other vertebrates including humans. During early ontogeny, zebrafish embryos are optically transparent, allowing researchers to visualize the dynamics of organogenesis using a simple stereomicroscope. Microbead implantation is a method that enables tissue manipulation through the alteration of factors in local environments. This allows researchers to assay the effects of any number of signaling molecules of interest, such as secreted peptides, at specific spatial and temporal points within the developing embryo. Here, we detail a protocol for how to manipulate and implant beads during early zebrafish development.

The zebrafish is an excellent model system for genetic and developmental studies. Bead implantation is a valuable tissue manipulation technique that can be used to interrogate developmental mechanisms by introducing alterations in local cellular environments. This protocol describes how to perform microbead implantation in the zebrafish embryo.

The zebrafish has emerged as a valuable genetic model system for the study of developmental biology and disease. Zebrafish share a high degree of genomic ...

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders. In the study of neuromuscular diseases, the integrity of the muscle membrane is a critical disease determinant. To date, numerous neuromuscular conditions display degenerating muscle fibers with abnormal membrane integrity; this is most commonly observed in muscular dystrophies. Evans Blue Dye (EBD) is a vital, cell permeable dye that is rapidly taken into degenerating, damaged, or apoptotic cells; in contrast, it is not taken up by cells with an intact membrane. EBD injection is commonly employed to ascertain muscle integrity in mouse models of neuromuscular diseases. However, such EBD experiments require muscle dissection and/or sectioning prior to analysis. In contrast, EBD uptake in zebrafish is visualized in live, intact preparations. Here, we demonstrate a simple and straightforward methodology for performing EBD injections and analysis in live zebrafish. In addition, we demonstrate a co-injection strategy to increase efficacy of EBD analysis. Overall, this video article provides an outline to perform EBD injection and characterization in zebrafish models of neuromuscular disease.

In this study, we describe a straightforward method to perform Evans Blue Dye (EBD) analysis on zebrafish larvae. This technique is a powerful tool for the characterization of skeletal muscle integrity and delineation of zebrafish models of muscular dystrophy, and is a valuable method for the development of novel therapeutics.

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Imaging Subcellular Structures in the Living Zebrafish Embryo

In vivo imaging provides unprecedented access to the dynamic behavior of cellular and subcellular structures in their natural context. Performing such imaging experiments in higher vertebrates such as mammals generally requires surgical access to the system under study. The optical accessibility of embryonic and larval zebrafish allows such invasive procedures to be circumvented and permits imaging in the intact organism. Indeed the zebrafish is now a well-established model to visualize dynamic cellular behaviors using in vivo microscopy in a wide range of developmental contexts from proliferation to migration and differentiation. A more recent development is the increasing use of zebrafish to study subcellular events including mitochondrial trafficking and centrosome dynamics. The relative ease with which these subcellular structures can be genetically labeled by fluorescent proteins and the use of light microscopy techniques to image them is transforming the zebrafish into an in vivo model of cell biology. Here we describe methods to generate genetic constructs that fluorescently label organelles, highlighting mitochondria and centrosomes as specific examples. We use the bipartite Gal4-UAS system in multiple configurations to restrict expression to specific cell-types and provide protocols to generate transiently expressing and stable transgenic fish. Finally, we provide guidelines for choosing light microscopy methods that are most suitable for imaging subcellular dynamics.

Imaging the dynamic behavior of organelles and other subcellular structures in vivo can shed light on their function in physiological and disease conditions. Here, we present methods for genetically tagging two organelles, centrosomes and mitochondria, and imaging their dynamics in living zebrafish embryos using wide-field and confocal microscopy.

In vivo imaging provides unprecedented access to the dynamic behavior of cellular and subcellular structures in their natural context. Performing such ...

Observing Mitotic Division and Dynamics in a Live Zebrafish Embryo

Mitosis is critical for organismal growth and differentiation. The process is highly dynamic and requires ordered events to accomplish proper chromatin condensation, microtubule-kinetochore attachment, chromosome segregation, and cytokinesis in a small time frame. Errors in the delicate process can result in human disease, including birth defects and cancer. Traditional approaches investigating human mitotic disease states often rely on cell culture systems, which lack the natural physiology and developmental/tissue-specific context advantageous when studying human disease. This protocol overcomes many obstacles by providing a way to visualize, with high resolution, chromosome dynamics in a vertebrate system, the zebrafish. This protocol will detail an approach that can be used to obtain dynamic images of dividing cells, which include: in vitro transcription, zebrafish breeding/collecting, embryo embedding, and time-lapse imaging. Optimization and modifications of this protocol are also explored. Using H2A.F/Z-EGFP (labels chromatin) and mCherry-CAAX (labels cell membrane) mRNA-injected embryos, mitosis in AB wild-type, auroraBhi1045, and esco2hi2865 mutant zebrafish is visualized. High resolution live imaging in zebrafish allows one to observe multiple mitoses to statistically quantify mitotic defects and timing of mitotic progression. In addition, observation of qualitative aspects that define improper mitotic processes (i.e., congression defects, missegregation of chromosomes, etc.) and improper chromosomal outcomes (i.e., aneuploidy, polyploidy, micronuclei, etc.) are observed. This assay can be applied to the observation of tissue differentiation/development and is amenable to the use of mutant zebrafish and pharmacological agents. Visualization of how defects in mitosis lead to cancer and developmental disorders will greatly enhance understanding of the pathogenesis of disease.

Mitosis is critical to every living organism and defects often lead to cancer and developmental disorders. Using this imaging protocol and zebrafish as a model system, researchers can visualize mitosis in a live vertebrate organism and the multitude of defects that arise when mitotic processes are defective.

Mitosis is critical for organismal growth and differentiation. The process is highly dynamic and requires ordered events to accomplish proper chromatin ...

AFM and Microrheology in the Zebrafish Embryo Yolk Cell

Elucidating the factors that direct the spatio-temporal organization of evolving tissues is one of the primary purposes in the study of development. Various propositions claim to have been important contributions to the understanding of the mechanical properties of cells and tissues in their spatiotemporal organization in different developmental and morphogenetic processes. However, due to the lack of reliable and accessible tools to measure material properties and tensional parameters in vivo, validating these hypotheses has been difficult. Here we present methods employing atomic force microscopy (AFM) and particle tracking with the aim of quantifying the mechanical properties of the intact zebrafish embryo yolk cell during epiboly. Epiboly is an early conserved developmental process whose study is facilitated by the transparency of the embryo. These methods are simple to implement, reliable, and widely applicable since they overcome intrusive interventions that could affect tissue mechanics. A simple strategy was applied for the mounting of specimens, AFM recording, and nanoparticle injections and tracking. This approach makes these methods easily adaptable to other developmental times or organisms.

The lack of tools to measure material properties and tensional parameters in vivo prevents validating their roles during development. We employed atomic force microscopy (AFM) and nanoparticle-tracking to quantify mechanical features on the intact zebrafish embryo yolk cell during epiboly. These methods are reliable and widely applicable avoiding intrusive interventions.

Elucidating the factors that direct the spatio-temporal organization of evolving tissues is one of the primary purposes in the study of development. ...

Immobilization of Caenorhabditis elegans to Analyze Intracellular Transport in Neurons

Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein are molecular motors that regulate anterograde and retrograde transport, respectively. These motors use microtubule networks as rails. Caenorhabditis elegans (C. elegans) is a powerful model organism to study axonal transport and IFT in vivo. Here, I describe a protocol to observe axonal transport and IFT in living C. elegans. Transported cargo can be visualized by tagging cargo proteins using fluorescent proteins such as green fluorescent protein (GFP). C. elegans is transparent and GFP-tagged cargo proteins can be expressed in specific cells under cell-specific promoters. Living worms can be fixed by microbeads on 10% agarose gel without killing or anesthetizing the worms. Under these conditions, cargo movement can be directly observed in the axons and cilia of living C. elegans without dissection. This method can be applied to the observation of any cargo molecule in any cells by modifying the target proteins and/or the cells they are expressed in. Most basic proteins such as molecular motors and adaptor proteins that are involved in axonal transport and IFT are conserved in C. elegans. Compared to other model organisms, mutants can be obtained and maintained more easily in C. elegans. Combining this method with various C. elegans mutants can clarify the molecular mechanisms of axonal transport and IFT.

Immobilization of Caenorhabditis elegans to Analyze Intracellular Transport in Neurons

Caenorhabditis elegans (C. elegans) is a good model to study axonal and intracellular transport. Here, I describe a protocol for in vivo recording and analysis of axonal and intraflagellar transport in C. elegans.

Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein ...

Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout (Oncorhynchus Mykiss) and Brown Trout (Salmo Trutta Morpha fario)

Egg collection is one of the most crucial procedures during fish reproduction in salmonid hatcheries. Classic methods involve the use of hand massage on fish abdomens to expel the eggs. An alternative method uses the pressure of gas injected into the body cavity, which causes the subsequent release of the eggs. This method is believed to have less negative effects on both the welfare and egg quality of the broodstocks. Herein, we compare the results of air and hand stripping methods with respect to one-year survival and egg quantity and quality in two salmonid fish, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta morpha fario). Our results indicate that air stripping yielded a better quality of eggs and higher one-year survival rate in rainbow trout. In addition, air stripping resulted in lower mortality rate than the group subjected to hand stripping (25% vs. 35%). The pH and hatching rate of the hand stripped group was lower than those of the air stripped group. In the case of brown trout, the quality of eggs obtained by both hand and air-stripping methods was similar; however, the one-year losses in fish were higher in air stripped group (15% compared to 0% in hand stripped fish). Although the advantages of air stripping method over hand stripping in terms of egg quality might not be observed in all salmonid species, the air-stripping procedure might be a promising option to be adopted in hatcheries as it ensures a high level of reproducibility and efficiency.

Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout Oncorhynchus Mykiss and Brown Trout Salmo Trutta Morpha fario

The principal aim of this study is to standardize and test the pneumatic method (air stripping) of collecting eggs in rainbow trout and brown trout. This method allows effective and simple collection of the eggs without the necessity of fish abdomen massage.

Egg collection is one of the most crucial procedures during fish reproduction in salmonid hatcheries. Classic methods involve the use of hand massage on ...

Following Endocardial Tissue Movements via Cell Photoconversion in the Zebrafish Embryo

During embryogenesis, cells undergo dynamic changes in cell behavior, and deciphering the cellular logic behind these changes is a fundamental goal in the field of developmental biology. The discovery and development of photoconvertible proteins have greatly aided our understanding of these dynamic changes by providing a method to optically highlight cells and tissues. However, while photoconversion, time-lapse microscopy, and subsequent image analysis have proven to be very successful in uncovering cellular dynamics in organs such as the brain or the eye, this approach is generally not used in the developing heart due to challenges posed by the rapid movement of the heart during the cardiac cycle. This protocol consists of two parts. The first part describes a method for photoconverting and subsequently tracking endocardial cells (EdCs) during zebrafish atrioventricular canal (AVC) and atrioventricular heart valve development. The method involves temporally stopping the heart with a drug in order for accurate photoconversion to take place. Hearts are allowed to resume beating upon removal of the drug and embryonic development continues normally until the heart is stopped again for high-resolution imaging of photoconverted EdCs at a later developmental time point. The second part of the protocol describes an image analysis method to quantify the length of a photoconverted or non-photoconverted region in the AVC in young embryos by mapping the fluorescent signal from the three-dimensional structure onto a two-dimensional map. Together, the two parts of the protocol allows one to examine the origin and behavior of cells that make up the zebrafish AVC and atrioventricular heart valve, and can potentially be applied for studying mutants, morphants, or embryos that have been treated with reagents that disrupt AVC and/or valve development.

This protocol describes a method for the photoconversion of Kaede fluorescent protein in endocardial cells of the living zebrafish embryo that enables the tracking of endocardial cells during atrioventricular canal and atrioventricular heart valve development.

During embryogenesis, cells undergo dynamic changes in cell behavior, and deciphering the cellular logic behind these changes is a fundamental goal in the ...