黑腹果蝇第三龄幼虫脑的活细胞成像
Summary
在这里，我们讨论了一种工作流程，用于准备、解剖、安装和成像来自黑 腹果蝇 第三龄幼虫的活外植体大脑，以观察生理条件下的细胞和亚细胞动力学。
Abstract
果蝇 神经干细胞（神经母细胞，以下简称NBs）经历不对称分裂，再生自我更新的神经母细胞，同时还形成分化神经节母细胞（GMC），该母细胞将经历一次额外的分裂以产生两个神经元或神经胶质细胞。NBs的研究揭示了细胞极性，纺锤体取向，神经干细胞自我更新和分化的分子机制。这些不对称的细胞分裂很容易通过活细胞成像 观察到 ，使幼虫NB非常适合研究活组织中不对称细胞分裂的时空动力学。当在营养补充培养基中正确解剖和成像时，外植体大脑中的NBs强烈分裂12-20小时。前面描述的方法在技术上是困难的，对于那些刚进入该领域的人来说可能具有挑战性。在这里，描述了使用脂肪体补充剂制备、解剖、安装和成像活的三龄幼虫脑外植体的方案。还讨论了潜在的问题，并提供了如何使用这种技术的示例。
Introduction
不对称细胞分裂 （ACD） 是亚细胞成分（如 RNA、蛋白质和细胞器）在子细胞之间分配不均等的过程 1,2。这个过程在干细胞中很常见，干细胞经历ACD以产生具有不同发育命运的子细胞。果蝇NBs不对称地分裂以产生一个NB，保留其干性，以及一个神经节母细胞（GMC）。GMC经历进一步的分裂以产生分化的神经元或神经胶质细胞3。不对称分裂的NBs在三龄幼虫的发育大脑中很丰富，通过显微镜很容易观察到。在第三龄幼虫阶段，每个中枢脑叶中大约有100个NBs3,4,5,6。
不对称细胞分裂是一个高度动态的过程。活细胞成像方案已被用于测量和量化细胞极性7,8,9,10，纺锤体取向11,12,13，肌动肌蛋白皮层14,15,16,17,18，微管和中心体生物学19,20的动力学，21,22,23,24,25,26,27和膜10,28和染色质动力学29。ACD的定性和定量描述依赖于可靠的方法和协议来成像完整活体大脑中的NBs分割。以下协议概述了使用两种不同的安装方法制备，解剖和成像用于体内活细胞成像的第三龄幼虫大脑的方法。这些方法最适合对干细胞分裂以及其他脑细胞分裂的时空动力学感兴趣的研究人员，因为它们允许对细胞事件进行短期和长期观察。此外，这些技术对于该领域的新手来说很容易获得。我们证明了这种方法在表达荧光标记的微管和皮质融合蛋白的幼虫脑中的有效性和适应性。我们还讨论了分析方法和在其他研究中应用的注意事项。
Protocol
注意： 图1 显示了进行本研究所需的材料。 1. 实验的注意事项和准备 防止幼虫过度拥挤。注意：外植体幼虫大脑的质量与解剖前幼虫的健康和质量直接相关。因过度拥挤而营养不良的幼虫通常会产生质量较低的大脑30。确保每个餐盖培养皿的幼虫不超过20-30只，以避免营养不良。这些示例如图 <strong class="xf…
Representative Results
中枢脑叶NBs的解剖和成像表达Pins：：EGFP和樱桃：：木星为了展示这一协议，表达UAS驱动的樱桃：：木星13和内源性标记的Pins：：EGFP16（w; worGal4，UAS-cherry：：jupiter/CyO;引脚：：EGFP / TM6B，Tb）使用多孔成像载玻片使用所述方案成像4小时（图5C，D）。其他数据取自表达UAS驱动的樱桃：：木星13的…
Discussion
该协议概述了一种从 黑腹果蝇 幼虫对活外植体大脑进行成像的方法。这里描述的方案允许在正确的实验条件下观察外植体大脑12-20小时。必须特别考虑样品的制备和所需实验的设计。如上所述，决定解剖组织质量的最关键因素之一是幼虫的健康。为了达到尽可能高的质量，必须确保幼虫在采集前得到良好的喂养。不健康的幼虫最常见的原因是过度拥挤。为了解决这个问题，必须确保通过增…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项研究得到了R35GM148160（C.C.）和美国国立卫生研究院（NIH）培训补助金T32 GM007270（R.C.S）的支持。
Materials
| 0.22 µm polyethersulfone (PES) Membrane | Genesee | 25-231 | Vacuum-driven filters |
| Agar | Genesee | 20-248 | granulated agar |
| Analytical Computer | Dell | NA | Intel Xeon Gold 5222 CPU with two 3.80 GHz processors running Windows 10 on a 64-bit operating system |
| Bovine Growth Serum | HyClone | SH30541.02 | |
| Chambered Imaging Slides | Ibidi | 80826 | |
| Confocal Microscope | Nikon | NA | |
| Custom-machined metal slide | NA | NA | See Cabernard and Doe 2013 (Ref. 34) for specifications |
| Dissection Dishes | Fisher Scientific | 5024343 | 3-well porcelain micro spot plate |
| Dissection Forceps | World Precision Instruments | Dumont #5 | |
| Dissection Microscope | Leica | NA | |
| Dissection Scissors | Fine Science Tools (FST) | 15003-08 | |
| Embryo collection cage | Genesee | 59-100 | |
| Flypad with access to CO2 to anesthetize adult flies | Genesee | 59-172 | |
| Gas-permeable membrane | YSI | 98095 | Gas-permeable membrane |
| Glass Cover Slides | Electron Microscopy Sciences | 72204-03 | # 1.5; 22 mm x 40 mm glass coverslips |
| Imaris | Oxford Instruments | NA | Alternatives: Fiji, Volocity, Aivia |
| Imaris File Converter | Oxford Instruments | NA | |
| Instant Yeast | Saf-Instant | NA | |
| Molasses | Genesee | 62-117 | |
| Petri dish | Greiner Bio-One | 628161 | 60 mm x 15 mm Petri dish |
| Petroleum Jelly | Vaseline | NA | |
| Schneider's Insect Medium with L-glutamine and sodium bicarbonate liquid | Millipore Sigma | S0146 | |
| SlideBook acquisition software | 3i | NA | |
| Vacuum-Driven Filtration Unit with a 0.22 µµm PES membrane filter | Genesee Scientific, GenClone | 25-231 |
References
- Delgado, M. K., Cabernard, C. Mechanical regulation of cell size, fate, and behavior during asymmetric cell division. Current Opinion in Cell Biology. 67, 9-16 (2020).
- Sunchu, B., Cabernard, C. Principles and mechanisms of asymmetric cell division. Development. 147 (13), (2020).
- Homem, C. C. F., Knoblich, J. A. Drosophila neuroblasts: A model for stem cell biology. Development. 139 (23), 4297-4310 (2012).
- Gallaud, E., Pham, T., Cabernard, C. Drosophila melanogaster neuroblasts: A model for asymmetric stem cell divisions. Results and Problems in Cell Differentiation. 61 (1489), 183-210 (2017).
- Loyer, N., Januschke, J. Where does asymmetry come from? Illustrating principles of polarity and asymmetry establishment in Drosophila neuroblasts. Current Opinion in Cell Biology. 62, 70-77 (2020).
- Pollington, H. Q., Seroka, A. Q., Doe, C. Q. From temporal patterning to neuronal connectivity in Drosophila type I neuroblast lineages. Seminars in Cell & Developmental Biology. 142, 4-12 (2023).
- Oon, C. H., Prehoda, K. Asymmetric recruitment and actin dependent cortical flows drive the neuroblast polarity cycle. eLife. 8, e45815 (2019).
- Ramat, A., Hannaford, M., Januschke, J. Maintenance of miranda localization in Drosophila neuroblasts involves interaction with the cognate mRNA. Current Biology. 27 (14), 2101-2111 (2017).
- Oon, C. H., Prehoda, K. E. Phases of cortical actomyosin dynamics coupled to the neuroblast polarity cycle. eLife. 10, e66574 (2021).
- LaFoya, B., Prehoda, K. E. Actin-dependent membrane polarization reveals the mechanical nature of the neuroblast polarity cycle. Cell Reports. 35 (7), 109146 (2021).
- Siller, K. H., Doe, C. Q. Lis1/dynactin regulates metaphase spindle orientation in Drosophila neuroblasts. 발생학. 319 (1), 1-9 (2008).
- Siller, K. H., Cabernard, C., Doe, C. Q. The NuMA-related Mud protein binds Pins and regulates spindle orientation in Drosophila neuroblasts. Nature Cell Biology. 8 (6), 594-600 (2006).
- Cabernard, C., Doe, C. Q. Apical/basal spindle orientation is required for neuroblast homeostasis and neuronal differentiation in Drosophila. Developmental Cell. 17 (1), 134-141 (2009).
- Cabernard, C., Prehoda, K. E., Doe, C. Q. A spindle-independent cleavage furrow positioning pathway. Nature. 467 (7311), 91-94 (2010).
- Connell, M., Cabernard, C., Ricketson, D., Doe, C. Q., Prehoda, K. E. Asymmetric cortical extension shifts cleavage furrow position in Drosophila neuroblasts. Molecular Biology of the Cell. 22 (22), 4220-4226 (2011).
- Tsankova, A., Pham, T. T., Garcia, D. S., Otte, F., Cabernard, C. Cell polarity regulates biased myosin activity and dynamics during asymmetric cell division via Drosophila rho kinase and protein kinase N. Developmental Cell. 42 (2), 143-155 (2017).
- Montembault, E., et al. Myosin efflux promotes cell elongation to coordinate chromosome segregation with cell cleavage. Nature Communications. 8 (1), 326 (2017).
- Roubinet, C., et al. Spatio-temporally separated cortical flows and spindle geometry establish physical asymmetry in fly neural stem cells. Nature Communications. 8 (1), 1383 (2017).
- Januschke, J., et al. Centrobin controls mother-daughter centriole asymmetry in Drosophila neuroblasts. Nature Cell Biology. 15 (3), 241-248 (2013).
- Januschke, J., Llamazares, S., Reina, J., Gonzalez, C. Drosophila neuroblasts retain the daughter centrosome. Nature Communications. 2 (1), 243 (2011).
- Rebollo, E., et al. Functionally unequal centrosomes drive spindle orientation in asymmetrically dividing Drosophila neural stem cells. Developmental Cell. 12 (3), 467-474 (2007).
- Januschke, J., Gonzalez, C. The interphase microtubule aster is a determinant of asymmetric division orientation in Drosophila neuroblasts. The Journal of Cell Biology. 188 (5), 693-706 (2010).
- Rusan, N. M., Peifer, M. A role for a novel centrosome cycle in asymmetric cell division. The Journal of Cell Biology. 177 (1), 13-20 (2007).
- Lerit, D. A., et al. Interphase centrosome organization by the PLP-Cnn scaffold is required for centrosome function. Journal of Cell Biology. 210 (1), 79-97 (2015).
- Gallaud, E., et al. Dynamic centriolar localization of Polo and Centrobin in early mitosis primes centrosome asymmetry. PLoS Biology. 18 (8), e3000762 (2020).
- Ramdas Nair, A., et al. The microcephaly-associated protein Wdr62/CG7337 is required to maintain centrosome asymmetry in Drosophila neuroblasts. Cell Reports. 14 (5), 1100-1113 (2016).
- Singh, P., Nair, A. R., Cabernard, C. The centriolar protein Bld10/Cep135 is required to establish centrosome asymmetry in Drosophila neuroblasts. Current Biology. 24 (13), 1548-1555 (2014).
- LaFoya, B., Prehoda, K. E. Consumption of a polarized membrane reservoir drives asymmetric membrane expansion during the unequal divisions of neural stem cells. Developmental Cell. 1534 (23), 00159 (2023).
- Sunchu, B., et al. Asymmetric chromatin retention and nuclear envelopes separate chromosomes in fused cells in vivo. Communications Biology. 5 (1), 953 (2022).
- Oliveira, A. C., Rebelo, A. R., Homem, C. C. F. Integrating animal development: How hormones and metabolism regulate developmental transitions and brain formation. 발생학. 475, 256-264 (2021).
- Britton, J. S., Edgar, B. A. Environmental control of the cell cycle in Drosophila: nutrition activates mitotic and endoreplicative cells by distinct mechanisms. Development. 125 (11), 2149-2158 (1998).
- Lee, C. -. Y., et al. Drosophila Aurora-A kinase inhibits neuroblast self-renewal by regulating aPKC/Numb cortical polarity and spindle orientation. Genes & Development. 20 (24), 3464-3474 (2006).
- Homem, C. C. F., Reichardt, I., Berger, C., Lendl, T., Knoblich, J. A. Long-term live cell imaging and automated 4D analysis of Drosophila neuroblast lineages. PLoS ONE. 8 (11), e79588 (2013).
- Cabernard, C., Doe, C. Q. Live imaging of neuroblast lineages within intact larval brains in Drosophila. Cold Spring Harbor Protocols. 2013 (10), 970-977 (2013).
- Karpova, N., Bobinnec, Y., Fouix, S., Huitorel, P., Debec, A. Jupiter, a new Drosophila protein associated with microtubules. Cell Motility and the Cytoskeleton. 63 (5), 301-312 (2006).
- Loyer, N., Januschke, J. The last-born daughter cell contributes to division orientation of Drosophila larval neuroblasts. Nature Communications. 9 (1), 3745 (2018).
- Bostock, M. P., et al. An immobilization technique for long-term time-lapse imaging of explanted Drosophila tissues. Frontiers in Cell and Developmental Biology. 8, 590094 (2020).
Cite This Article
Segura, R. C., Cabernard, C. Live-Cell Imaging of Drosophila melanogaster Third Instar Larval Brains. J. Vis. Exp. (196), e65538, doi:10.3791/65538 (2023).