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>

The authors have nothing to disclose.

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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		<col />
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		<col />
	</colgroup>
	<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

8.2K visualizações.  University of Maryland, Baltimore County. 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...