Name: Pleins feux sur l’auteur : Comprendre le réseau de microtubules dans les jonctions neuromusculaires de la drosophile
Uploaded: 2023-10-20T14:00:00
Description: Watch this Scientific Journal Video about Understanding Microtubule Network in Drosophila Neuromuscular Junctions at JoVE.com

Nous remercions le Dr Ying Xiong pour les discussions et les commentaires sur le manuscrit. Ces travaux sont soutenus par une subvention de la National Science Foundation of China (NSFC) à C. M. (31500839).

1. Dissection des larves
REMARQUE : La solution de dissection solution saline de type hémolymphatique (HL3.1)18 et la solution de fixation à 4% de paraformaldéhyde (PFA)19,20 sont utilisées à température ambiante car les microtubules se dépolymérisent lorsque la température est trop basse.
<ol><li>Repérez une larve errante du 3e stade à l’aide d’une longue pince émo...

Observation des réseaux de microtubules dans les jonctions neuromusculaires et les cellules musculaires de la drosophile

<ol>
	<li>Halpain, S., Dehmelt, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+MAP1+family+of+microtubule-associated+proteins.">The MAP1 family of microtubule-associated proteins.</a> Genome biology. 7 (6), 224 (2006).</li><li>S&#225;nchez, C., D&#237;az-Nido, J., Avila, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorylation+of+microtubule-associated+protein+2+(MAP2)+and+its+relevance+for+the+regulation+of+the+neuronal+cytoskeleton+function.">Phosphorylation of microtubule-associated protein 2 (MAP2) and its relevance for the regulation of the neuronal cytoskeleton function.</a> Progress in neurobiology. 61 (2), 133-168 (2000).</li><li>Dehmelt, L., Halpain, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+MAP2/Tau+family+of+microtubule-associated+proteins.">The MAP2/Tau family of microtubule-associated proteins.</a> Genome biology. 6 (1), 204 (2005).</li><li>Roll-Mecak, A., McNally, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule-severing+enzymes.">Microtubule-severing enzymes.</a> Current opinion in cell biology. 22 (1), 96-103 (2010).</li><li>Walczak, C. E., Gayek, S., Ohi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule-depolymerizing+kinesins.">Microtubule-depolymerizing kinesins.</a> Annual review of cell and developmental biology. 29, 417-441 (2013).</li><li>Bramblett, G. T., 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=Abnormal+tau+phosphorylation+at+Ser396+in+Alzheimer's+disease+recapitulates+development+and+contributes+to+reduced+microtubule+binding.">Abnormal tau phosphorylation at Ser396 in Alzheimer's disease recapitulates development and contributes to reduced microtubule binding.</a> Neuron. 10 (6), 1089-1099 (1993).</li><li>Van Vactor, D., Sigrist, 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=Presynaptic+morphogenesis,+active+zone+organization+and+structural+plasticity+in+Drosophila.">Presynaptic morphogenesis, active zone organization and structural plasticity in Drosophila.</a> Current opinion in neurobiology. 43, 119-129 (2017).</li><li>Hummel, T., Krukkert, K., Roos, J., Davis, G., Kl&#228;mbt, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+Futsch/22C10+is+a+MAP1B-like+protein+required+for+dendritic+and+axonal+development.">Drosophila Futsch/22C10 is a MAP1B-like protein required for dendritic and axonal development.</a> Neuron. 26 (2), 357-370 (2000).</li><li>Roos, J., Hummel, T., Ng, N., Kl&#228;mbt, C., Davis, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+Futsch+regulates+synaptic+microtubule+organization+and+is+necessary+for+synaptic+growth.">Drosophila Futsch regulates synaptic microtubule organization and is necessary for synaptic growth.</a> Neuron. 26 (2), 371-382 (2000).</li><li>Packard, M., 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=The+Drosophila+Wnt,+wingless,+provides+an+essential+signal+for+pre-+and+postsynaptic+differentiation.">The Drosophila Wnt, wingless, provides an essential signal for pre- and postsynaptic differentiation.</a> Cell. 111 (3), 319-330 (2002).</li><li>Dent, E. W., Callaway, J. L., Szebenyi, G., Baas, P. W., Kalil, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reorganization+and+movement+of+microtubules+in+axonal+growth+cones+and+developing+interstitial+branches.">Reorganization and movement of microtubules in axonal growth cones and developing interstitial branches.</a> The Journal of neuroscience: the official journal of the Society for Neuroscience. 19 (20), 8894-8908 (1999).</li><li>Tanaka, E. M., Kirschner, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtubule+behavior+in+the+growth+cones+of+living+neurons+during+axon+elongation.">Microtubule behavior in the growth cones of living neurons during axon elongation.</a> The Journal of cell biology. 115 (2), 345-363 (1991).</li><li>Ahmad, F. J., Yu, W., McNally, F. J., Baas, P. W. <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+role+for+katanin+in+severing+microtubules+in+the+neuron.">An essential role for katanin in severing microtubules in the neuron.</a> The Journal of cell biology. 145 (2), 305-315 (1999).</li><li>Hu, Z., 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=Fidgetin+regulates+cultured+astrocyte+migration+by+severing+tyrosinated+microtubules+at+the+leading+edge.">Fidgetin regulates cultured astrocyte migration by severing tyrosinated microtubules at the leading edge.</a> Molecular biology of the cell. 28 (4), 545-553 (2017).</li><li>Feizabadi, M. S., Castillon, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+Tau+and+taxol+on+polymerization+of+MCF7+microtubules+in+vitro.">The effect of Tau and taxol on polymerization of MCF7 microtubules in vitro.</a> International journal of molecular sciences. 23 (2), 677 (2022).</li><li>Velasco, C. D., 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+depolymerization+contributes+to+spontaneous+neurotransmitter+release+in+vitro.">Microtubule depolymerization contributes to spontaneous neurotransmitter release in vitro.</a> Communications biology. 6 (1), 488 (2023).</li><li>H&#246;&#246;g, J. L., 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=Electron+tomography+reveals+a+flared+morphology+on+growing+microtubule+ends.">Electron tomography reveals a flared morphology on growing microtubule ends.</a> Journal of cell science. 124, 693-698 (2011).</li><li>Feng, Y., Ueda, A., Wu, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+minimal+hemolymph-like+solution,+HL3.1,+for+physiological+recordings+at+the+neuromuscular+junctions+of+normal+and+mutant+Drosophila+larvae.">A modified minimal hemolymph-like solution, HL3.1, for physiological recordings at the neuromuscular junctions of normal and mutant Drosophila larvae.</a> Journal of neurogenetics. 18 (2), 377-402 (2004).</li><li>Broadie, K. S., Bate, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+embryonic+neuromuscular+synapse+of+Drosophila+melanogaster.">Development of the embryonic neuromuscular synapse of Drosophila melanogaster.</a> The Journal of neuroscience: the official journal of the Society for Neuroscience. 13 (1), 144-166 (1993).</li><li>Xiong, Y., 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=HDAC6+mutations+rescue+human+tau-induced+microtubule+defects+in+Drosophila.">HDAC6 mutations rescue human tau-induced microtubule defects in Drosophila.</a> Proceedings of the National Academy of Sciences of the United States of America. 110 (12), 4604-4609 (2013).</li><li>Sullivan, W., Ashburner, M., Hawley, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Drosophila Protocols. , (2000).</li><li>Mao, C. X., 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-severing+protein+Katanin+regulates+neuromuscular+junction+development+and+dendritic+elaboration+in+Drosophila.">Microtubule-severing protein Katanin regulates neuromuscular junction development and dendritic elaboration in Drosophila.</a> Development. 141 (5), 1064-1074 (2014).</li><li>Jin, S., 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=Drosophila+Tubulin-specific+chaperone+E+functions+at+neuromuscular+synapses+and+is+required+for+microtubule+network+formation.">Drosophila Tubulin-specific chaperone E functions at neuromuscular synapses and is required for microtubule network formation.</a> Development. 136 (9), 1571-1581 (2009).</li><li>Sarthi, J., Elefant, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=dTip60+HAT+activity+controls+synaptic+bouton+expansion+at+the+Drosophila+neuromuscular+junction.">dTip60 HAT activity controls synaptic bouton expansion at the Drosophila neuromuscular junction.</a> PloS one. 6 (10), 26202 (2011).</li><li>Weingarten, M. D., Lockwood, A. H., Hwo, S. Y., Kirschner, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protein+factor+essential+for+microtubule+assembly.">A protein factor essential for microtubule assembly.</a> Proceedings of the National Academy of Sciences of the United States of America. 72 (5), 1858-1862 (1975).</li><li>Kadavath, 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=Tau+stabilizes+microtubules+by+binding+at+the+interface+between+tubulin+heterodimers.">Tau stabilizes microtubules by binding at the interface between tubulin heterodimers.</a> Proceedings of the National Academy of Sciences of the United States of America. 112 (24), 7501-7506 (2015).</li><li>Trotta, N., Orso, G., Rossetto, M. G., Daga, A., Broadie, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hereditary+spastic+paraplegia+gene,+spastin,+regulates+microtubule+stability+to+modulate+synaptic+structure+and+function.">The hereditary spastic paraplegia gene, spastin, regulates microtubule stability to modulate synaptic structure and function.</a> Current biology: CB. 14 (13), 1135-1147 (2004).</li></ol>

Un protocole est décrit ici pour la dissection et l’immunomarquage des jonctions neuromusculaires et des cellules musculaires des larves de drosophile . Il y a plusieurs points essentiels à considérer. Tout d’abord, il est crucial d’éviter de blesser les muscles observés pendant le processus de dissection. Il peut être utile de fixer le filet avant de retirer les organes internes pour éviter tout contact direct entre la pince et les muscles. Pour éviter les lésions musculaires ou la séparation de...

Les microtubules (MT), en tant que l’un des composants structurels du cytosquelette, jouent un rôle important dans divers processus biologiques, notamment la division cellulaire, la croissance et la motilité cellulaires, le transport intracellulaire et le maintien de la forme cellulaire. La dynamique et la fonction des microtubules sont modulées par des interactions avec d’autres protéines, telles que MAP1, MAP2, Tau, Katanine et Kinésine 1,2,3,4,5.
Dans les neurones, les microtubules sont essentiels au développement et au maintien des axones et des dendrites. Des anomalies dans les microtubules entraînent un dysfonctionnement et même la mort des neurones. Par exemple, dans le cerveau des patients atteints de la maladie d’Alzheimer, l’hyperphosphorylation de la protéine Tau réduit la stabilité du réseau de microtubules, provoquant des irrégularités neurologiques6. Ainsi, l’examen des réseaux de microtubules contribuera à une compréhension du neurodéveloppement et de la pathogenèse des maladies neurologiques.
La jonction neuromusculaire (NMJ) est la synapse périphérique formée entre une terminaison axonale de motoneurone et une fibre musculaire, qui est un système modèle excellent et puissant pour l’étude de la structure et des fonctions synaptiques7. Futsch est une protéine de la drosophile qui est homologue à la protéine de liaison aux microtubules MAP1B que l’on trouve chez les mammifères8. Il ne s’exprime que dans les neurones et joue un rôle dans le développement des boutons synaptiques de la JNM 8,9. Dans le type sauvage, les faisceaux filamenteux qui longent le centre des processus NMJ sont visualisés par immunomarquage avec un anti-Futsch. Lorsqu’il atteint l’extrémité de la JNM, ce faisceau a la capacité soit de former une boucle constituée de microtubules, soit de perdre sa structure filamenteuse, ce qui donne un aspect diffus et ponctué10. Les boucles de microtubules sont associées à des cônes de croissance en pause, ce qui suggère que le réseau de microtubules est stable11. Par conséquent, nous pouvons déterminer indirectement le développement de microtubules stables dans la JNM par coloration de Futsch. La grande taille des cellules musculaires de la larve de drosophile permet une visualisation claire du réseau de microtubules. Les facteurs affectant la stabilité du réseau de microtubules peuvent être trouvés en analysant la densité et la forme des microtubules. Simultanément, l’état du réseau de microtubules des cellules musculaires peut être vérifié de manière croisée avec le résultat de la JNM pour obtenir des conclusions plus complètes.
De nombreux protocoles ont été utilisés pour étudier le réseau et la dynamique des microtubules. Cependant, ces recherches se sont souvent concentrées sur des études in vitro 12,13,14,15,16. Alternativement, certaines expériences in vivo ont utilisé la microscopie électronique pour détecter le cytosquelette17. Du fait de la liaison spécifique d’anticorps marqués par fluorescence ou de colorants chimiques à des protéines ou à de l’ADN, les méthodes présentées ici permettent la détection de réseaux de microtubules dans les JNM au niveau des neurones individuels in vivo, avec des résultats corroborés par des observations dans les cellules musculaires. Ce protocole est simple, stable et reproductible lorsqu’il est combiné avec les puissants outils génétiques disponibles chez Drosophila melanogaster, permettant une gamme variée d’examens phénotypiques et de criblages génétiques pour le rôle des protéines régulatrices du réseau de microtubules dans le système nerveux in vivo.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alexa Fluor Plus 405 phalloidin</td>
			<td>invitrogen</td>
			<td>A30104</td>
			<td>dilute 1:200</td>
		</tr>
		<tr>
			<td>Enhanced Antifade Mounting Medium</td>
			<td>Beyotime</td>
			<td>P0128M</td>
			<td></td>
		</tr>
		<tr>
			<td>FV10-ASW confocal microscope</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-Mouse antibody, Alexa Fluor 488 conjugated</td>
			<td>Thermo Fisher</td>
			<td>A-11001</td>
			<td>dilute 1:1,000</td>
		</tr>
		<tr>
			<td>Laser confocal microscope LSM 710</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Scissors</td>
			<td>66vision</td>
			<td>54138B</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-Futsch antibody</td>
			<td>Developmental Studies Hybridoma Bank&#160;&#160;</td>
			<td>22C10</td>
			<td>dilute 1:50</td>
		</tr>
		<tr>
			<td>Mouse anti-&#945;-tubulin antibody</td>
			<td>Sigma</td>
			<td>T5168</td>
			<td>dilute 1:1,000</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Wako</td>
			<td>168-20955</td>
			<td>Final concentration: 4% in PB Buffer</td>
		</tr>
		<tr>
			<td>Stainless Steel Minutien Pins</td>
			<td>Entomoravia</td>
			<td></td>
			<td>0.1mm Diam</td>
		</tr>
		<tr>
			<td>Stereomicroscope SMZ161</td>
			<td>Motic</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>stereoscopic fluorescence microscope BX41</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Texas Red-conjugated goat anti-HRP</td>
			<td>Jackson ImmunoResearch</td>
			<td></td>
			<td>dilute 1:100</td>
		</tr>
		<tr>
			<td>TO-PRO(R) 3 iodide</td>
			<td>Invitrogen</td>
			<td>T3605</td>
			<td>dilute 1:1,000</td>
		</tr>
		<tr>
			<td>Transfer decoloring shaker TS-8</td>
			<td>Kylin-Bell lab instruments</td>
			<td>E0018</td>
			<td></td>
		</tr>
		<tr>
			<td>TritonX-100</td>
			<td>BioFroxx</td>
			<td>1139</td>
			<td></td>
		</tr>
		<tr>
			<td>Tweezers&#160;</td>
			<td>dumont</td>
			<td>500342</td>
			<td></td>
		</tr>
	</tbody>
</table>

using drosophila larval neuromuscular junction and muscle cells to visualize microtubule network

Le réseau de microtubules est une composante essentielle du système nerveux. Des mutations dans de nombreuses protéines régulatrices des microtubules sont associées à des troubles neurodéveloppementaux et à des maladies neurologiques, telles que la protéine Tau associée aux microtubules aux maladies neurodégénératives, la protéine sectionnante des microtubules Spastin et Katanin 60 provoquent respectivement une paraplégie spastique héréditaire et des anomalies neurodéveloppementales. La détection de réseaux de microtubules dans les neurones est avantageuse pour élucider la pathogenèse des troubles neurologiques. Cependant, la petite taille des neurones et la disposition dense des faisceaux de microtubules axonaux rendent difficile la visualisation des réseaux de microtubules. Dans cette étude, nous décrivons une méthode de dissection de la jonction neuromusculaire larvaire et des cellules musculaires, ainsi que l’immunomarquage de la α-tubuline et de la protéine de Futsch associée aux microtubules pour visualiser les réseaux de microtubules chez Drosophila melanogaster. La jonction neuromusculaire nous permet d’observer à la fois les microtubules pré et post-synaptiques, et la grande taille des cellules musculaires de la larve de drosophile permet une visualisation claire du réseau de microtubules. Ici, en mutant et en surexprimant Katanin 60 chez Drosophila melanogaster, puis en examinant les réseaux de microtubules dans la jonction neuromusculaire et les cellules musculaires, nous révélons avec précision le rôle régulateur de Katanin 60 dans le neurodéveloppement. Par conséquent, combiné aux puissants outils génétiques de Drosophila melanogaster, ce protocole facilite grandement le criblage génétique et l’analyse de la dynamique des microtubules pour le rôle des protéines régulatrices du réseau de microtubules dans le système nerveux.

Microtubules (MTs), as one of the structural components of the cytoskeleton, play an important role in diverse biological processes, including cell division, cell growth and motility, intracellular transport, and the maintenance of cell shape. Microtubule dynamics and function are modulated by interactions with other proteins, such as MAP1, MAP2, Tau, Katanin, and Kinesin1,2,3,4,5.
In neurons, microtubules are essential for the development and maintenance of axons and dendrites. Abnormalities in microtubules lead to dysfunction and even the death of neurons. For instance, in the brain of Alzheimer&#39;s patients, Tau protein hyperphosphorylation reduces the stability of the microtubule network, causing neurological irregularities6. Thus, examining microtubule networks will contribute to a comprehension of neurodevelopment and the pathogenesis of neurological diseases.
The neuromuscular junction (NMJ) is the peripheral synapse formed between a motor neuron axon terminal and a muscle fiber, which is an excellent and powerful model system for studying synaptic structure and functions7. Futsch is a protein in Drosophila that is homologous to the microtubule-binding protein MAP1B found in mammals8. It is expressed only in neurons and plays a role in the development of the NMJ&#39;s synaptic buttons8,9. In wild-type, filamentous bundles that run along the center of NMJ processes are visualized by immunostaining with anti-Futsch. When reaching NMJ&#39;s end, this bundle has the ability to either form a loop consisting of microtubules or to lose its filamentous structure, resulting in a diffuse and punctate appearance10. Microtubule loops are associated with paused growth cones, which suggests the microtubule array is stable11. Therefore, we can indirectly determine the stable microtubule development in NMJ by Futsch staining. The large size of muscle cells in Drosophila larva allows for clear visualization of the microtubule network. The factors affecting the stability of the microtubule network can be found by analyzing the density and shape of microtubules. Simultaneously, the microtubule network status of muscle cells can be cross-verified with the result of NMJ to obtain more comprehensive conclusions.
Many protocols have been employed for investigating the network and dynamics of microtubules. However, these researches have often focused on in vitro studies12,13,14,15,16. Alternatively, some in vivo experiments have employed electron microscopy to detect the cytoskeleton17. According to the specific binding of fluorescently labeled antibodies or chemical dyes to proteins or DNA, the methods presented here allow the detection of microtubule networks in NMJ at the level of individual neurons in vivo, with results corroborated by observations in muscle cells. This protocol is simple, stable, and repeatable when combined with the powerful genetic tools available in Drosophila melanogaster, enabling a diverse range of phenotypic examinations and genetic screenings for the role of microtubule network regulatory proteins in the nervous system in vivo.

Pleins feux sur l’auteur : Comprendre le réseau de microtubules dans les jonctions neuromusculaires de la drosophile 

Utilisation de la jonction neuromusculaire larvaire de drosophile et des cellules musculaires pour visualiser le réseau de microtubules

Currently, microtubule dynamics are observed indirectly through microtubule-binding proteins such as EB1. Since alphabeta tubulin heterodimers are abundant in the cytoplasm, fold directly, neighboring tubulin heterodimers are lacking the dynamics of microtubule networks in vivo. Our protocol visualizes microtubules in neuromuscular synapses and muscle cells.When combined with the powerful genetic tools available in Drosophila melanogaster, enabling a diverse range of phenotypic examinations and the genetic screening for the role of microtubule network regulatory proteins in the nervous system in vivo. Our research focuses on the relationship between the cytoskeleton and the neurodevelopment, as well as its implications for neurological diseases. We hope to discover the mechanism of neurodevelopment and the parthenogenesis for neurological diseases by highlighting the effect of cytoskeletal regulatory proteins on neurons.

Nous avons démontré une procédure étape par étape pour visualiser le réseau de microtubules dans les jonctions neuromusculaires (JNM) et les cellules musculaires. Après la dissection selon le schéma de principe (Figure 1A-E), l’immunomarquage est effectué, puis les images sont observées et recueillies sous un microscope confocal laser ou un microscope à fluorescence stéréoscopique (Figure 1F,G).
<p class="jove...

Watch this Scientific Journal Video about Understanding Microtubule Network in Drosophila Neuromuscular Junctions at JoVE.com

Nous présentons ici un protocole détaillé pour visualiser les réseaux de microtubules dans les jonctions neuromusculaires et les cellules musculaires. Combiné aux puissants outils génétiques de Drosophila melanogaster, ce protocole facilite grandement le criblage génétique et l’analyse de la dynamique des microtubules pour le rôle des protéines régulatrices du réseau de microtubules dans le système nerveux.

The microtubule network is an essential component of the nervous system. Mutations in many microtubules regulatory proteins are associated with ...

Actuellement, la dynamique des microtubules est observée indirectement par l’intermédiaire de protéines de liaison aux microtubules telles que EB1. Étant donné que les hétérodimères de tubuline alphabeta sont abondants dans le cytoplasme, se replient directement, les hétérodimères de tubuline voisins n’ont pas la dynamique des réseaux de microtubules in vivo. Notre protocole permet de visualiser les microtubules dans les synapses neuromusculaires et les cellules musculaires.Lorsqu’il est combiné avec les puissants outils génétiques disponibles chez Drosophila melanogaster, il permet une gamme variée d’examens phénotypiques et le criblage génétique du rôle des protéines régulatrices du réseau de microtubules dans le système nerveux in vivo. Nos recherches portent sur la relation entre le cytosquelette et le neurodéveloppement, ainsi que sur ses implications pour les maladies neurologiques. Nous espérons découvrir le mécanisme du neurodéveloppement et de la parthénogenèse des maladies neurologiques en mettant en évidence l’effet des protéines régulatrices du cytosquelette sur les neurones.

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Research

JoVE Journal

Neuroscience

Using Drosophila Larval Neuromuscular Junction and Muscle Cells to Visualize Microtubule Network

The microtubule network is an essential component of the nervous system. Mutations in many microtubules regulatory proteins are associated with neurodevelopmental disorders and neurological diseases, such as microtubule-associated protein Tau to neurodegenerative diseases, microtubule severing protein Spastin and Katanin 60 cause hereditary spastic paraplegia and neurodevelopmental abnormalities, respectively. Detection of microtubule networks in neurons is advantageous for elucidating the pathogenesis of neurological disorders. However, the small size of neurons and the dense arrangement of axonal microtubule bundles make visualizing the microtubule networks challenging. In this study, we describe a method for dissection of the larval neuromuscular junction and muscle cells, as well as immunostaining of &#945;-tubulin and microtubule-associated protein Futsch to visualize microtubule networks in Drosophila melanogaster. The neuromuscular junction permits us to observe both pre-and post-synaptic microtubules, and the large size of muscle cells in Drosophila larva allows for clear visualization of the microtubule network. Here, by mutating and overexpressing Katanin 60 in Drosophila melanogaster,&#160;and then examining the microtubule networks in the neuromuscular junction and muscle cells, we&#160;accurately reveal the regulatory role of Katanin 60 in neurodevelopment. Therefore, combined with the powerful genetic tools of Drosophila&#160;melanogaster, this protocol greatly facilitates genetic screening and microtubule dynamics analysis for the role of microtubule network regulatory proteins in the nervous system.

Here, we present a detailed protocol to visualize the microtubule networks in neuromuscular junctions and muscle cells. Combined with the powerful genetic tools of Drosophila melanogaster, this protocol greatly facilitates genetic screening and microtubule-dynamics analysis for the role of microtubule network regulatory proteins in the nervous system.

Recherche

Neurosciences

Drosophila Larval Dissection and Fixation for Microtubule Visualization

Begin by picking out a wandering Drosophila third instar larva using long blunt forceps. Wash the larva with hemolymph-like saline, then dry it with a wipe. Next, position the larva dorsally or ventrally on a dissection dish under the stereo microscope.Depending on the tissue to be observed, opt for dorsal or ventral dissection. Pin the larva's mouth hooks and tail to maintain extended positioning. Next, add a drop of the hemolymph-like saline to prevent the larva from drying.Using dissection scissors, make a small transverse incision close to the posterior end without severing it completely. Proceed to cut along the ventral midline, moving toward the anterior end. Now insert four insect pins each into the corners of the larva.Make necessary adjustments to the insect pins to maximize the stretching of the larva. Use forceps to gently remove the internal organs while avoiding harm to the muscles. To fix the larva, immerse the carcasses in 100 L of 4%paraformaldehyde, while still affixed to the dissecting dish.After this, dismount the pins. Then transfer the sample into a 2 mL microcentrifuge tube filled with 0.2%PBST. Place the tube on a shaker for 10 minutes at 15 RPM.

Drosophile Dissection larvaire et fixation pour la visualisation des microtubules

Immunohistochemistry of Drosophila Larva for Microtubule Visualization

Remove the PBST and immerse the paraformaldehyde-fixed drosophila larval carcasses in a blocking agent for 40 minutes at room temperature. Replace the blocking agent with 200 microliters of the primary antibody diluted with 0.2%PBST. Leave the larvae to incubate at four degrees Celsius overnight.The next day, wash the larvae with 0.2%PBST for 10 minutes. Next, remove the PBST from the tube and add 200 microliters of diluted secondary antibody. Incubate it at ambient temperature for 1.5 hours in the dark.Introduce a nuclear dye such as TO-PRO R 3 iodide into the incubating tube for 30 minutes while staining the microtubules in the dark. Finally, rinse off the secondary antibody and the nuclear dye with 0.2%PBST for 10 minutes.

Immunohistochimie de la larve de drosophile pour la visualisation des microtubules

Mounting and Image Acquisition of Drosophila Larval Microtubules

Begin by placing the antibody labeled drosophila larval carcasses in 0.2%PBST on a glass slide. Adjusted under the stereo microscope, ensuring that the inner surface of the larval carcass is facing up. Absorb the excess PBST solution using a wipe.Then delicately add a drop of Anti-Fade mounting medium. Next place a cover slip on the slide covering the dissected larvae slowly and gently, avoiding bubble formation. Secure the cover slip in place by applying fingernail polish around its edges.Store the slide in a dark location to minimize fluorescent attenuation. For image acquisition, use the laser scanning confocal microscope with the 63x Oil immersion objective. Then adjust the wavelength and laser power to fit the requirements of the experiment best.To identify the neuromuscular junctions and capture images of muscle four in segment A three, select a 488 nanometer laser to activate alpha tubulin or Futsch, and 546 nanometers to activate the HRP imaging track. Modify the parameters to achieve a frame size of 1, 024 by 1, 024 pixels, a digital zoom of 1.0, and an imaging interval of 0.8 micrometers. To visualize microtubules in the muscle, capture images of muscle two in the segments A three to A five as it has fewer tracheal branches.Choose a 488 nanometer laser for activating alpha tubulin and a 633 nanometer laser for activating the T3605 imaging track. Adjust the imaging parameters to a frame size of 1, 024 by 1, 024 pixels, a digital zoom of 2.0, and an imaging interval of 0.4 micrometers. Both pre-and post-synaptic microtubule organizations of the neuromuscular junction were labeled with anti-alpha tubulin.Futsch staining reflected the abundance of stable microtubules in the pre-synaptic neurons. Decreased signal intensity of anti-Futsch was observed when microtubules severing protein Katanin 60 was overexpressed in the presynaptic neurons. The staining intensity of the axon trunk was stronger than that of the branches.Katanin 60 mutations resulted in increased microtubule loops. Overexpression of Katanin 60 caused short microtubule fragments within the terminal buttons. Alpha tubulin staining demonstrated a clear network of microtubules around the nucleus.Muscle cells had a significantly increased perinuclear microtubular intensity and exhibited stronger bundles in the Katanin 60 mutant. Overexpression resulted in fragmentation of the microtubule fibers.