单细胞分辨荧光活成像在幼虫脑培养中的果蝇昼夜节律时钟
Summary
该协议的目的是建立活体果蝇幼虫脑培养优化监测昼夜节律分子节律与长期荧光时间推移成像。并对该方法在药理实验中的应用进行了探讨。
Abstract
昼夜节律起搏器电路协调节律的行为和生理输出与环境的提示, 如昼夜循环。在每个起搏器神经元的分子时钟产生的基因表达的昼夜节律, 这基础的节律性神经元功能的运作的电路。不同类型的起搏器神经元的单个分子振荡器的性质及其与神经元信号相互作用的研究能更好地了解昼夜节律起搏器电路。在这里, 我们提出了一个时间推移荧光显微镜的方法来监测时钟神经元的分子发条的培养果蝇幼虫脑。这种方法允许多天记录的节奏, 基因编码荧光昼夜记者在单细胞的决议。这种设置可以结合药理操作, 密切分析分子时钟对各种化合物的实时响应。除了昼夜节律之外, 这种多用途方法与强大的果蝇基因技术结合, 为研究活体脑组织中的不同神经元或分子过程提供了可能性。
Introduction
生物钟帮助生物体适应地球 24 h 自转产生的周期性环境变化。互锁转录-平移反馈回路通常基础上的分子机械的昼夜生物钟的各种物种1。由时钟包含的神经元组成的昼夜节律起搏器电路集成了由环境提示 (如光/暗 (LD) 和温度循环) 所传达的时间信息, 以协调每天过多的生理和行为进程2,3。分子节律与神经元输入和输出的协调对于昼夜节律回路的运行至关重要, 但仍只部分了解。
在果蝇中, 在分子时钟的核心, 时钟/周期 (赤 CYC) heterodimer 激活句点(每) 和永恒(tim) 的转录。每和 TIM 形成一个复杂的, 并进入细胞核, 在那里他们抑制转录活动的时钟/CYC, 因此他们自己的转录。转录后和后转化的规则导致时钟/CYC 介导的转录和压制之间的延迟/TIM, 确保产生约 24 h 分子振荡1,3,4.大约150神经元含有这些分子时钟形成一个电路来控制成人苍蝇的昼夜行为5。一个更简单而功能完整的昼夜节律电路, 由3组时钟神经元组成, 5 腹侧神经元 (LNvs; 4 个 pdf 阳性 LNvs 和一个 pdf 阴性 LNv, 见下), 2 背神经 1s (DN1s) 和2背神经元 2s (DN2s)-存在于幼虫大脑6,7。
简单的幼虫昼夜节律电路提供了一个很好的模型来研究神经元间的交流和分子发条之间的相互作用。利用我们新开发的每 TDT 的荧光报告器, 它模拟每个蛋白质的水平和它的亚细胞位置, 我们试图在幼虫昼夜节律回路中表征不同时钟神经元子群的分子发条的动力学特性8. 此外, 知道神经肽颜料分散因子 (PDF) 的关键作用, 4 LNvs 在调节神经元水平的昼夜节律9,10,11, 我们想检查直接PDF 对分子时钟的影响。为此, 我们开发了一种方法, 监测昼夜节律基因表达节律的幼虫脑外植体多天的时间推移共聚焦显微镜。该协议也适用于药理测试, 以检验 PDF 或其他化合物对每 TDT 的水平的影响。因此, 这种适应包括使脑外植体培养可用于药物应用, 增加时间分辨率和成像时间更短。
不同发育阶段的果蝇大脑的前体培养已经建立12,13,14,15,16,17 ,18。虽然这些协议已被用于成像各种生物现象, 其中一些是不兼容的成像在单细胞分辨率或不支持的文化超过几个小时。在果蝇中对昼夜节律神经元进行长期实时成像的替代方法包括分子节律的生物荧光成像19、20、21和荧光成像钙指示物与轻的板料显微学22,23。虽然生物荧光成像可以实现更高的时间分辨率和光片显微镜可以适应在体内成像, 他们是有限的空间分辨率和要求专门的显微镜系统。
本文所描述的方法是在多天的单细胞分辨率下, 针对全脑培养中的荧光信号进行可视化。这种轻便和多才多艺的方法可以适应于图像培养成人苍蝇脑和药理实验研究许多不同的问题, 在果蝇神经生物学。
Protocol
1. 在文化罩下准备库存解决方案 准备400毫升的1x 施耐德活性培养基 (SAM) 优化的ex 体内培养幼体的大脑 (修改从参考24,25) (表 1)。分到5毫升, 在液氮中闪冻 (在2), 存储在-80 ° c。 通过稀释10x 库存溶液 (从参考26中修改) (表 2), 准备1x 解剖盐水溶液 (DSS)。 分纤维蛋白原为10毫克,…
Representative Results
在这里, 我们展示了长期记录的代表性的结果, 一个昼夜荧光记者在前体内幼虫脑培养, 和实时成像结果的 PDF 沐浴应用的记者表达。 非游荡 L3 幼虫表达分子时钟记者每 TDT 和 UAS-mCD8::YFP 驱动的时钟神经元驱动程序时钟(856)-gal4 (图 1C) 在 LD 中夹带. 大脑被解剖, 并建立了长期的文化在最后LD 周?…
Discussion
在这里, 我们描述了长期荧光时间推移显微镜的培养幼体大脑的方法。这类实验的成功与否取决于多种因素, 如培养的健康、对大脑外植体的固定化方法、荧光强度和报告者的信噪比、时间和空间分辨率, 以及外植体的可及性。这些因素可以相互排斥。例如, 增加的时间推移频率影响到文化的健康, 和固定的大脑外植体可能阻碍气体交换。因此, 找到一个快乐的媒体 (没有双关语) 的现象正在研究中是…
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
我们感谢迈克尔 Rosbash 在这个方法发展的最初阶段的指导和支持。这项工作由 JST 方案、瑞士国家科学基金会 (31003A_149893 和 31003A_169548)、欧洲研究理事会 (ERC-StG-311194)、诺华医学生物医学研究基金会 (13A39) 和日内瓦大学资助。.
Materials
| KH2PO4 | Sigma-Aldrich | P5655 | I am not sure they are exactly the same ones we have in the lab. I chose "suitable for insect cell culture" whenever available |
| CaCl2 | Sigma-Aldrich | C7902 | |
| MgSO4.7H2O | Sigma-Aldrich | 230391 | |
| NaCl | Sigma-Aldrich | S5886 | |
| NaHCO3 | Sigma-Aldrich | S5761 | |
| D-(+) Glucose | Sigma-Aldrich | G7021 | |
| Yeast extract | Sigma-Aldrich | Y1000 | |
| Insulin | Sigma-Aldrich | I0516-5ML | |
| Penicillin-Streptomycin | Sigma-Aldrich | P4333 | |
| BIS-TRIS | Sigma-Aldrich | B4429 | |
| L-(−)-Malic acid | Sigma-Aldrich | M7397 | |
| D-(+)-Trehalose dihydrate | Sigma-Aldrich | T0167 | |
| Succinic acid | Sigma-Aldrich | S9512 | |
| Fumaric acid | Sigma-Aldrich | F8509 | |
| α-Ketoglutaric acid | Sigma-Aldrich | K1128 | |
| Non-heat-inactivated, Foetal Calf Serum (FCS) Mycoplasma and Virus screened | BioConcept Ltd. Amimed | 2-01F30-I | |
| HEPES-KOH, pH 7.4 | E&K Scientific Products | EK-654011 | |
| KCl | Sigma-Aldrich | P5405 | |
| NaH2PO4 | Sigma-Aldrich | S5011 | |
| Sucrose | Sigma-Aldrich | S7903 | |
| Fibrinogen from bovine plasma | Calbiochem (Merck) | 341573-1GM | CAUTION: Harmful by inhalation, in contact with skin and if swallowed. Manipulate under laminar flow |
| Thrombin from bovine plasma | Sigma-Aldrich | T9549 | CAUTION: Health Hazard, use gloves |
| PDF, NH2-NSELINSLLSLPKNMNDA-OH | Chi Scientific | custom made | |
| Vaccum grease | Sigma-Aldrich | 18405 | |
| 35 mm Dish, No. 1.5 Coverslip, 20 mm Glass Diameter, Uncoated | MatTek | P35G-1.5-20-C | |
| Corning Falcon Easy-Grip Tissue Culture Dishes | fisherscientific | 08-772A | |
| Sterile 500 mL Steritop-GP 33 mm threaded bottle top filter, 0.22 μm | Millipore | SCGPS05RE | |
| Polytetrafluoroethylene (PTFE) film | Dupont | 200A Teflon FEP Film | |
| Millex-HV Syringe Filter Unit, 0.45 µm, PVDF, 33 mm, gamma sterilized | Millipore | SLHV033RS | |
| Millex-GV Syringe Filter Unit, 0.22 µm, PVDF, 33 mm, gamma sterilized | Millipore | SLGV033RS | |
| Three-well glass dissection dish | Any company | ||
| Fine forceps, size 5, Dumont | Fine Science Tools | 11254-20 | |
| Tandem scanner inverted TCS SP5 confocal microscope, with resonant scanner and HyD photo-multiplier detectors | Leica microsystem CMS GmbH | ||
| Temperature control chamber | Life Imaging Services | The CUBE & BOX temperature control system, custom designed | |
| Stage-top humidity controller | Life Imaging Services | custom made | |
| Water Immersion Micro Dispenser: dispenser, extended micro-pump MP6 series and Autoimmersion Objective Controller software | Leica microsystem CMS GmbH | ||
| SUM-stack creation and 3D correction drift plugin | ImageJ software | ||
| 10x iterative deconvolution | AutoQuant and Imaris software |
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Diesen Artikel zitieren
Sabado, V., Nagoshi, E. Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture. J. Vis. Exp. (131), e57015, doi:10.3791/57015 (2018).