Name: 作者聚焦：研究果蝇神经回路组装和突触形成的机制
Uploaded: 2024-07-26T14:45:00
Description: The protocol describes single-neuron ablation with a 2-photon laser system in the central nervous system (CNS) of intact Drosophila melanogaster larvae. ...

在 FAU Stiles-Nicholson 脑研究所高级细胞成像核心中对 2 光子显微镜进行了实验。我们要感谢 Jupiter Life Science Initiative 的财政支持。

用于该方案的所有动物都属于黑腹果蝇物种。围绕该物种的使用不存在道德问题。开展这项工作不需要道德审查。材料表中列出了研究中使用的果蝇物种、试剂和设备的详细信息。
1. 培育 果蝇 并选择正确的幼虫阶段
<ol><li>选择驱动待消融细胞表达的 Gal4 驱动系，并将其与 UAS-GFP 报告基因系重组或交叉。在 25 °C 的标准果蝇食物?...

果蝇单神经元消融研究神经系统适应

<ol>
	<li>Chung, S. H., Mazur, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Femtosecond+laser+ablation+of+neurons+in+C.+elegans+for+behavioral+studies.">Femtosecond laser ablation of neurons in C. elegans for behavioral studies.</a> Appl Phys A Mater Sci Process. 96 (2), 335-341 (2009).</li><li>Bower, D. V., 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=Airway+branching+has+conserved+needs+for+local+parasympathetic+innervation+but+not+neurotransmission.">Airway branching has conserved needs for local parasympathetic innervation but not neurotransmission.</a> BMC Biol. 12, 92 (2014).</li><li>Angelo, J. R., Tremblay, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser-mediated+cell+ablation+during+post-implantation+mouse+development.">Laser-mediated cell ablation during post-implantation mouse development.</a> Dev Dyn. 242 (10), 1202-1209 (2013).</li><li>Allen, M. J., Godenschwege, T. A., Tanouye, M. A., Phelan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Making+an+escape:+Development+and+function+of+the+Drosophila+giant+fibre+system.">Making an escape: Development and function of the Drosophila giant fibre system.</a> Semin Cell Dev Biol. 17 (1), 31-41 (2006).</li><li>Hubel, D. H., Wiesel, T. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Binocular+interaction+in+striate+cortex+of+kittens+reared+with+artificial+squint.">Binocular interaction in striate cortex of kittens reared with artificial squint.</a> J Neurophysiol. 28 (6), 1041-1059 (1965).</li><li>Wiesel, T. N., Hubel, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+effects+of+unilateral+and+bilateral+eye+closure+on+cortical+unit+responses+in+kittens.">Comparison of the effects of unilateral and bilateral eye closure on cortical unit responses in kittens.</a> J Neurophysiol. 28 (6), 1029-1040 (1965).</li><li>Brand, A. H., Perrimon, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+gene+expression+as+a+means+of+altering+cell+fates+and+generating+dominant+phenotypes.">Targeted gene expression as a means of altering cell fates and generating dominant phenotypes.</a> Development. 118 (2), 401-415 (1993).</li><li>Allen, M. J., Drummond, J. A., Moffat, K. G. <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+giant+fiber+neuron+of+Drosophila+melanogaster.">Development of the giant fiber neuron of Drosophila melanogaster.</a> J Comp Neurol. 397 (4), 519-531 (1998).</li><li>Burra, S., Wang, Y., Brock, A. R., Galko, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+Drosophila+larvae+to+study+epidermal+wound+closure+and+inflammation.">Using Drosophila larvae to study epidermal wound closure and inflammation.</a> Methods Mol Biol. 1037, 449-461 (2013).</li><li>Kakanj, P., Eming, S. A., Partridge, L., Leptin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+in+vivo+imaging+of+Drosophila+larvae.">Long-term in vivo imaging of Drosophila larvae.</a> Nat Protoc. 15 (3), 1158-1187 (2020).</li><li>Bainbridge, S. P., Bownes, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staging+the+metamorphosis+of+Drosophila+melanogaster.">Staging the metamorphosis of Drosophila melanogaster.</a> J Embryol Exp Morphol. 66, 57-80 (1981).</li><li>Allen, M. J., Godenschwege, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+recordings+from+the+Drosophila+giant+fiber+system+(GFs).">Electrophysiological recordings from the Drosophila giant fiber system (GFs).</a> Cold Spring Harb Protoc. 2010 (7), 5453 (2010).</li><li>Augustin, H., Allen, M. J., Partridge, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+recordings+from+the+giant+fiber+pathway+of+d.+Melanogaster.">Electrophysiological recordings from the giant fiber pathway of d. Melanogaster.</a> J Vis Exp. (47), e2412 (2011).</li><li>Boerner, J., Godenschwege, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole+mount+preparation+of+the+adult+Drosophila+ventral+nerve+cord+for+giant+fiber+dye+injection.">Whole mount preparation of the adult Drosophila ventral nerve cord for giant fiber dye injection.</a> J Vis Exp. (52), e3080 (2011).</li><li>Blagburn, J. M., Alexopoulos, H., Davies, J. A., Bacon, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Null+mutation+in+shaking-b+eliminates+electrical,+but+not+chemical,+synapses+in+the+Drosophila+giant+fiber+system:+A+structural+study.">Null mutation in shaking-b eliminates electrical, but not chemical, synapses in the Drosophila giant fiber system: A structural study.</a> J Comp Neurol. 404 (4), 449-458 (1999).</li><li>Kennedy, T., 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=Newly+identified+electrically+coupled+neurons+support+development+of+the+Drosophila+giant+fiber+model+circuit.">Newly identified electrically coupled neurons support development of the Drosophila giant fiber model circuit.</a> eNeuro. 5 (6), 0346 (2018).</li><li>Mcfarland, B. W., 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=Axon+arrival+times+and+physical+occupancy+establish+visual+projection+neuron+integration+on+developing+dendrites+in+the+Drosophila+optic+glomeruli.">Axon arrival times and physical occupancy establish visual projection neuron integration on developing dendrites in the Drosophila optic glomeruli.</a> bioRxiv. , (2024).</li></ol>

事实证明，使用 2 光子显微镜进行细胞消融是操纵 果蝇神经元回路发育的一种非常成功的方法。由于这种方法是非侵入性的，因此对动物造成的伤害最小。数据支持这种对已知电路的单元特异性操作的有用性。
消融成功的关键是选择最合适的 Gal4 驱动程序。由于 GFS 得到了很好的研究，因此已经描述了许多特定的 Gal4 驱动程序系列7。大多数 Gal4 驱动?...

激光消融是解剖各种生物体神经回路的首选工具。它在蠕虫和苍蝇等模型遗传系统中开发，已应用于整个动物王国，以研究神经系统的结构、功能和发育 1,2,3。在这里，采用单神经元消融来研究神经元在果蝇回路组装过程中如何相互作用。果蝇的逃逸系统是最受欢迎的分析回路，因为它包含成年果蝇中最大的神经元和最大的突触，并且该回路在过去几十年中得到了很好的表征4。神经元-神经元相互作用在 Giant Fiber 电路的组装中的作用是本研究的重点。
自 1960 年代 Hubel 和 Wiesel 的工作以来，一种相互作用一直是神经科学的焦点，即“突触竞争”5,6。在该协议中，激光消融用于重新审视通过单细胞消融在果蝇巨纤维系统 （GFS） 中的竞争作用，在那里可能会发现该现象的分子基础。
由于各种原因，包括可视化目标神经元、消融方法的精度以及标本的存活率，对发育中的果蝇中的神经元进行消融一直很困难。为了克服 GFS 中的这些问题，使用 UAS/Gal4 系统7 标记感兴趣的神经元，并使用双光子显微镜去除突触前巨纤维或突触后跳跃运动神经元 （TTMn）。
在这项研究中，为了确定相邻的双侧神经元在调整 GFS 中的突触连接和突触强度中的作用，在蛹发育前删除了双侧神经元对之一（突触前 GF 或突触后运动神经元）。在这个发育阶段，GF 轴突发生尚未完成8。然后检查成人突触回路的 GF 结构和功能，特别注意剩余 GF 的输出。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alexa Fluor 488 AffiniPure Goat Anti-Rabbit IgG (H+L)</td>
			<td>Jaxkson ImmunoResearch</td>
			<td>111-545-003</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-green fluorescent protein, rabbit</td>
			<td>Fisher Scientific</td>
			<td>A11122</td>
			<td>1:500 concentration</td>
		</tr>
		<tr>
			<td>Apo LWD 25x/1.10W Objective</td>
			<td>Nikon</td>
			<td>MRD77220</td>
			<td>water immersion long working distance</td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin (BSA)</td>
			<td>Sigma</td>
			<td>B4287-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Chameleon Ti:Sapphire Vision II Laser</td>
			<td>Coherent</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton Ball</td>
			<td>Genesee Scientific</td>
			<td>51-101</td>
			<td></td>
		</tr>
		<tr>
			<td>Dextra, Tetramethylrhodamine, 10,000 MW, Lysine Fixable (fluoro-Ruby)</td>
			<td>Fisher Scientific</td>
			<td>D1817</td>
			<td></td>
		</tr>
		<tr>
			<td>Drosophila saline</td>
			<td></td>
			<td></td>
			<td>recipe from Gu and O&#39;Dowd, 2006</td>
		</tr>
		<tr>
			<td>Ethyl Ether</td>
			<td>Fisher Scientific</td>
			<td>E134-1</td>
			<td>Danger, Flammable liquid</td>
		</tr>
		<tr>
			<td>Fly food B (Bloomington recipe)</td>
			<td>LabExpress</td>
			<td>7001-NV</td>
			<td></td>
		</tr>
		<tr>
			<td>Methyl salicylate</td>
			<td>Fisher Scientific</td>
			<td>O3695-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge tube 1.5 mL</td>
			<td>Eppendorf</td>
			<td>22363204</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope cover-slip 18x18 #1.5</td>
			<td>Fisher Scientific</td>
			<td>12-541A</td>
			<td></td>
		</tr>
		<tr>
			<td>Neurobiotin Tracer</td>
			<td>Vector Laboratories</td>
			<td>SP-1120</td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon A1R multi-photon microscope</td>
			<td>Nikon</td>
			<td></td>
			<td>on an upright FN1 microsope stand</td>
		</tr>
		<tr>
			<td>NIS Elements Advanced Research</td>
			<td>Nikon</td>
			<td></td>
			<td>Acquisition and data analysis software</td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)</td>
			<td>Fisher Scientific</td>
			<td>T353-500</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS (Phosphate Buffered Salin)</td>
			<td>Fisher BioReagents</td>
			<td>BP2944-100</td>
			<td>Tablets</td>
		</tr>
		<tr>
			<td>R91H05-Gal4</td>
			<td>Bloomington Drosophila Stock Center</td>
			<td>40594</td>
			<td></td>
		</tr>
		<tr>
			<td>shakB(lethal)-GAl4</td>
			<td>Bloomington Drosophila Stock Center</td>
			<td>51633</td>
			<td></td>
		</tr>
		<tr>
			<td>Superfrost microscope glass slide</td>
			<td>Fisher Scientific</td>
			<td>12-550-143</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Fisher Scientific</td>
			<td>422355000</td>
			<td>detergent solution</td>
		</tr>
		<tr>
			<td>UAS-10xGFP</td>
			<td>Bloomington Drosophila Stock Center</td>
			<td>32185</td>
			<td></td>
		</tr>
	</tbody>
</table>

laser cell ablation in intact drosophila larvae reveals synaptic competition

该方案描述了在完整黑腹果蝇幼虫的中枢神经系统 （CNS） 中使用 2 光子激光系统进行单神经元消融。使用这种非侵入性方法，可以以细胞特异性方式操纵发育中的神经系统。破坏网络中单个神经元的发育可用于研究神经系统如何补偿突触输入的损失。在果蝇的巨纤维系统中，单个神经元被特异性消融，重点是两个神经元：突触前巨纤维 （GF） 和突触后尾转子运动神经元 （TTMn）。GF 与同侧 TTMn 突触，这对逃逸反应至关重要。在 GF 开始轴突生长后，消融第 3 龄大脑中的一个 GF，在 CNS 发育过程中永久去除细胞。剩余的 GF 与缺失的邻居发生反应，并与对侧 TTMn 形成异位突触末端。这种非典型的、双侧对称的末端支配两个 TTMns（如染料偶联所示），并驱动两个运动神经元（如电生理学测定所示）。总之，单个中间神经元的消融表明双侧神经元之间的突触竞争可以补偿一个神经元的损失并恢复对逃逸回路的正常反应。

Laser ablation is a preferred tool for dissecting neural circuits in a wide variety of organisms. Developed in model genetic systems like worms and flies, it has been applied across the animal kingdom to study the structure, function, and development of the nervous system1,2,3. Here, single-neuron ablation was employed to investigate how neurons interact during circuit assembly in Drosophila. The escape system of the fly is a favorite circuit for analysis because it contains the largest neurons and the largest synapses in the adult fly, and the circuit has been well-characterized in the past decades4. The role neuron-neuron interactions play in the assembly of the Giant Fiber circuit is a focal point of this research.
One type of interaction that has been a focal point in neuroscience since the work of Hubel and Wiesel in the 1960s is &#34;synaptic competition&#34;5,6. In this protocol, laser ablation was used to revisit the role of competition through single-cell ablation in the giant fiber system (GFS) of Drosophila, where the molecular underpinnings of the phenomena might be discovered.
Ablation of neurons in the developing fly has been difficult for a variety of reasons, including visualizing the target neurons, the precision of the ablation method, and the survival of the specimen. To overcome these problems in the GFS, the UAS/Gal4 system7 was used to label neurons of interest, and a two-photon microscope was used to remove the presynaptic giant fiber or the postsynaptic jump motor neuron (TTMn).
In this study, to determine the role that neighboring bilateral neurons play in adjusting synaptic connectivity and synaptic strength in the GFS, one of the bilateral pairs of neurons (either presynaptic GF or postsynaptic motor neuron) was deleted just before pupal development. At this developmental stage, GF axonogenesis has not been completed8. The GF structure and function of the synaptic circuit in the adult were then examined, with particular attention given to the output of the remaining GF.

作者聚焦：研究果蝇神经回路组装和突触形成的机制

完整 果蝇 幼虫中的激光细胞消融揭示了突触竞争

We are trying to understand the mechanisms underlying neural circuit assembly during development, and we use simple nervous systems like drosophila to study this question. One of these mechanisms is the role of synaptic competition in circuit assembly, and the present paper is focused on this issue. One exciting new technology in neuroscience is called optogenetics.It uses light sensitive ion channels to turn neurons on or off using light pulses. These new methods allow us to control neural circuitry in new ways and link the circuits to behavior. Ablation of a single neuron in the living animal has allowed us to characterize the role of competition in the assembly of simple neural circuits.Now we can screen for the molecular machinery that underlies this widespread phenomenon. We demonstrate a competitive interaction between the two giant neurons for synaptic contact with their target motor neurons. This result has paralleled throughout the animal kingdom, especially in the vertebrate visual system where it was first discovered.This paves the way for investigating the molecules that regulate this competition in a genetically tractable organism like drosophila. We will use this new method of optogenetics to enhance our understanding of the neural circuit underlying the escape behavior. We will also use our understanding of the neural circuit to better understand how these new optogenetic tools work.

该方法可用于操纵 果蝇神经系统中特定神经元网络的发育。这里的主要研究问题是突触连接的形成。去除突触前 GF 或突触后 TTMn 能够研究该中央突触的反应性突触发生以及对突触功能和发育至关重要的分子机制。如方案中所述，对其中一个 GF 或其中一个 TTMns 进行了激光细胞消融，并分析了成年果蝇蛹发育后对突触的影响。
为确保该程序不会对动物生存产生负面影响?...

该协议展示了完整 果蝇 幼虫中单个神经元的激光细胞消融。该方法能够研究减少发育中的神经系统中神经元之间竞争的效果。

The protocol describes single-neuron ablation with a 2-photon laser system in the central nervous system (CNS) of intact Drosophila melanogaster larvae. ...

laser-cell-ablation-intact-drosophila-larvae-reveals-synaptic

Research

JoVE Journal

Neuroscience

Laser Cell Ablation in Intact Drosophila Larvae Reveals Synaptic Competition

The protocol describes single-neuron ablation with a 2-photon laser system in the central nervous system (CNS) of intact Drosophila melanogaster larvae. Using this non-invasive method, the developing nervous system can be manipulated in a cell-specific manner. Disrupting the development of individual neurons in a network can be used to study how the nervous system can compensate for the loss of synaptic input. Individual neurons were specifically ablated in the giant fiber system of Drosophila, with a focus on two neurons: the presynaptic giant fiber (GF) and the postsynaptic tergotrochanteral motor neuron (TTMn). The GF synapses with the ipsilateral TTMn, which is crucial to the escape response. Ablating one of the GFs in the 3rd instar brain, just after the GF starts axonal growth, permanently removes the cell during the development of the CNS. The remaining GF reacts to the absent neighbor and forms an ectopic synaptic terminal to the contralateral TTMn. This atypical, bilaterally symmetric terminal innervates both TTMns, as demonstrated by dye coupling, and drives both motor neurons, as demonstrated by electrophysiological assays. In summary, the ablation of a single interneuron demonstrates synaptic competition between a bilateral pair of neurons that can compensate for the loss of one neuron and restore normal responses to the escape circuit.

This protocol demonstrates the laser cell ablation of individual neurons in intact Drosophila larvae. The method enables the study of the effect of reducing competition between neurons in the developing nervous system.

科研

神经科学

Laser Ablation of Neurons in Intact Drosophila Third Instar Larva for Neuronal Manipulation

To begin, take a glass dish with a tightly-fitting lid. Place a cotton ball in the dish. Under a fume hood, add three to five milliliters of ethyl ether to the cotton ball.Immediately cover the dish with the lid. Use a paintbrush to pick up the third instar larvae of drosophila from fly vials. Transfer one larva into a small, open container.Place the container in the glass dish with ethyl ether, and immediately close the dish tightly. Use a dissection microscope to check the larva for mobility every 30 seconds. Transfer the anesthetized larva onto a glass microscope slide.Submerge the larvae in a drop of insect saline. Under the dissection microscope. Remove most of the saline with a paper tissue.Position the larva dorsal side up for giant fiber ablation, or the ventral side up for TTMn ablation. Then slowly lower a glass cover slip onto the larva. Add saline to the side of the cover slip.To fill-in the space between the glass slide and the cover slip. For giant fiber ablation, check the positioning of the brain under high-magnification on the dissection microscope. Ensure the brain is lying level and is visible through the cuticle.To displace any fat tissue covering the brain, use forceps to apply slight pressure to the cover slip and move the cover slip from side to side. Place the sample on a multi-photon microscope stage. Use the GFP filter to locate the sample in epifluorescence mode.For giant fiber ablation, focus on the cells of interest, then switch to two photon mode. Set the laser to 870 nanometers and adjust the detector gain to view the GFP expressing cells with the Galvano scanner, define the area for ablation using a circular region of interest. Next, proceed to set up the ablation protocol in the software, to do so, sequentially set one frame of acquisition, stimulation, followed by another frame of acquisition.Start the stimulation laser power at a lower value and run the stimulation protocol. If the ablation was not successful and only bleach the cell, increase the laser power by increments of 5%or the number of loops one at a time, and run the protocol again. Do this until successful cell ablation is seen.After successfully ablating the cell, remove the cover slip. With a paintbrush, gently pick up the larvae from the slide, then transfer the larvae into a food vial. In giant fiber ablation samples.The ablation was verified through the absence of a GFP-labeled soma on the ablated side of the brain. For the TTMn ablated larvae. The absence of TTMn on one side was easily recognized due to missing soma and dendrites.