Characterisation of the dorsal clock neurons in the circadian system of Drosophila: the neuronal circuits for multi-modal integration.

果蝇昼夜节律系统中背侧时钟神经元的表征：多模式整合的神经元回路。

• 批准号: 426544743
• 负责人: Professorin Dr. Charlotte Förster
• 金额: --
• 依托单位: Lehrstuhl für Neurobiologie und Genetik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426544743?language=en
• 关键词: Characterisation; dorsal; clock; neurons; circadian

The circadian clock enables animals to be prepared in advance for the regular changes between day and night. Furthermore, some animals use their circadian clock for the memory of time, the measurement of day length (to anticipate seasonal changes) and for time-compensated sky compass orientation. The circadian clock network in the brain of the fruit fly belongs to the best-investigated. It consists of interconnected lateral and dorsal clock neurons, which generate circadian molecular oscillations and mediate these to downstream interneurons and neurosecretory centres in the dorsal protocerebrum. During the last years the fruit fly became a model in sleep research; the first connections from the circadian clock to metabolism have been established, it was demonstrated that fruit flies have a time memory and that the clock is involved in diapause induction. Even the first hints exist that fruit flies are able to perform time-compensated sky compass orientation. The dorsal clock neurons appear to be involved in all these clock functions. While the lateral neurons represent "master oscillators", the dorsal neurons are multimodal integrators that are essential for transferring the circadian rhythms to downstream interneurons and neurosecretory cells. Nevertheless, recent studies are controversial concerning the exact role of the dorsal neurons. Some authors claim that a special group of dorsal neurons (the DN1p) is responsible for sleep, whereas others postulate a role of the same neurons in arousal and elevated metabolism. The reason for these contradicting views lies most probably in the diverse neuronal projections of individual DN1p neurons. We could show that the dorsal neurons represent extremely heterogeneous groups of cells, but that their neuronal projections are still insufficiently characterized. We plan to close this gap by labelling the neurons individually (with the help of Flybow and Multiple Colour FlpOut) and by clarifying the synaptic connections among themselves and between the lateral neurons (by "trans-Tango" and "functional GRASP"). Immunocytochemical staining with specific antibodies will unravel the neuropeptide expression of the dorsal neurons and by cAMP- and Ca2+-Imaging we will clarify to which other clock neurons these neuropeptides signal. The effects of selected neuropeptides on the circadian molecular oscillations in the different groups of clock neurons will be tested by in vivo luciferase recordings in cultured brains. Finally, we will investigate the exact role of selected clock neurons in the fly circadian system via behavioural recordings, starting with the DN1a that we have already partly characterized. We expect that our investigations will significantly advance the understanding of the neuronal clock network in the fly and other animals.

生物钟使动物能够提前为昼夜之间的规律变化做好准备。此外，一些动物使用它们的生物钟来记忆时间，测量白天的长度（预测季节变化）和时间补偿的天空罗盘方向。果蝇大脑中的生物钟网络属于研究得最好的。它由相互连接的外侧和背侧时钟神经元组成，这些神经元产生昼夜分子振荡，并将其介导到背侧前脑中的下游中间神经元和神经分泌中心。在过去的几年里，果蝇成为睡眠研究的模型;已经建立了从生物钟到新陈代谢的第一个联系，证明果蝇具有时间记忆，并且生物钟参与滞育诱导。即使是第一个线索存在，果蝇能够执行时间补偿的天空罗盘方向。背时钟神经元似乎参与了所有这些时钟功能。虽然侧神经元代表“主振荡器”，背神经元是多模态集成器，其对于将昼夜节律传递到下游中间神经元和神经分泌细胞是必不可少的。然而，最近的研究是有争议的背神经元的确切作用。一些作者声称，一组特殊的背神经元（DN 1 p）负责睡眠，而其他人则假设相同的神经元在唤醒和代谢升高中发挥作用。这些相互矛盾的观点的原因在于最有可能在不同的神经元投射个别DN 1 p神经元。我们可以证明背神经元代表了极其异质的细胞群，但它们的神经元投射仍然没有充分的特征。我们计划通过单独标记神经元（在Flybow和Multiple Colour FlpOut的帮助下）并通过澄清它们之间以及侧神经元之间的突触连接（通过“trans-Tango”和“功能性GRASP”）来缩小这一差距。用特异性抗体进行免疫细胞化学染色将解开背神经元的神经肽表达，并通过cAMP-和Ca 2 +-成像，我们将澄清这些神经肽信号传递给哪些其他时钟神经元。所选神经肽对不同组的时钟神经元中的昼夜节律分子振荡的影响将通过在培养的脑中的体内荧光素酶记录来测试。最后，我们将通过行为记录研究选定的时钟神经元在果蝇昼夜节律系统中的确切作用，从我们已经部分表征的DN 1a开始。我们希望我们的研究将显着推进苍蝇和其他动物的神经元时钟网络的理解。