Genetic programmes for dendrite regrowth after pruning in Drosophila - mechanistic and functional aspects

果蝇修剪后树突再生的遗传程序 - 机制和功能方面

• 批准号: 452851300
• 负责人: Dr. Sebastian Rumpf
• 金额: --
• 依托单位: Institut für Neuro- und Verhaltensbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/452851300?language=en
• 关键词: Genetic; programmes; dendrite; regrowth; after

The establishment of the mature neuronal connectivity during development often occurs in distinct phases of progressive and regressive events. In particular, connectivity can be remodeled through regulated degeneration of neurites and synapses, a process known as pruning. In such cases, neurons can regrow new neurites or synapses with altered connectivity. While several examples of such remodeling have been described from invertebrates to mammals, little is known about how pruning and regrowth are coordinated at the molecular level and what the consequences of failed pruning and/or regrowth are for neuronal function. A well-suited model to study pruning mechanisms are Drosophila peripheral sensory neurons, which prune their larval sensory dendrites at the onset of metamorphosis and later regrow them with adult-specific morphology. While the molecular mechanisms underlying the initial dendrite pruning are beginning to emerge, little is known about dendrite regrowth. We could previously show that dendrite pruning is regulated at the level of translation initiation, apparently in order to limit protein biosynthesis. In contrast, we found that molecular pathways promoting protein biosynthesis – the Target of Rapamycin (TOR) pathway, and also mRNA splicing, are required for dendrite regrowth after pruning in an apparently specific manner. This raises the question as to whether a global upregulation of protein biosynthesis is sufficient to promote dendrite regrowth, or whether specific mRNAs must be spliced correctly and translated. In addition, it is not clear how dendrite regrowth is linked to adult sensory neuron function. Here, we propose to systematically identify the genetic basis for dendrite regrowth after pruning. To this end, we will (1) perform candidate RNAi screens to identify the regulatory gene networks for dendrite regrowth; (2) identify downstream targets of TOR and splicing factors using candidate approaches and RNAseq, respectively and (3) develop functional behavioral assays for adult sensory neuron function to assess the effects of regrowth (and also pruning) defects. Our project will provide important insights into the interplay between pruning, regrowth, and neuronal function.

在发育过程中，成熟神经元连接的建立通常发生在渐进和退行事件的不同阶段。特别是，连接可以通过神经突和突触的调节变性来重塑，这一过程被称为修剪。在这种情况下，神经元可以再生新的神经突或突触与改变连接。虽然已经描述了从无脊椎动物到哺乳动物的几个这样的重塑的例子，但是关于修剪和再生在分子水平上是如何协调的以及失败的修剪和/或再生对神经元功能的后果知之甚少。一个非常适合的模型来研究修剪机制是果蝇外周感觉神经元，它修剪他们的幼虫感觉树突在变态的发病和后来再生他们与成人特定的形态。虽然最初的树突修剪的分子机制开始出现，很少有人知道树突再生。我们以前可以表明，树突修剪是在翻译起始水平上调节的，显然是为了限制蛋白质的生物合成。相比之下，我们发现促进蛋白质生物合成的分子途径-雷帕霉素靶（TOR）途径，以及mRNA剪接，是修剪后树突再生长所必需的。这就提出了一个问题，即蛋白质生物合成的整体上调是否足以促进树突再生，或者特定的mRNA是否必须正确剪接和翻译。此外，树突再生与成年感觉神经元功能的关系尚不清楚。在这里，我们建议系统地确定修剪后树突再生的遗传基础。为此，我们将（1）进行候选RNAi筛选，以确定树突再生的调控基因网络;（2）分别使用候选方法和RNAseq确定TOR和剪接因子的下游靶标;（3）开发成人感觉神经元功能的功能行为测定，以评估再生（以及修剪）缺陷的影响。我们的项目将提供重要的见解修剪，再生和神经元功能之间的相互作用。