Vonhoff F, Duch C
School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA.
J Comp Neurol. 2010 Jun 15;518(12):2169-85. doi: 10.1002/cne.22380.
Different types of neurons can be distinguished by the specific targeting locations and branching patterns of their dendrites, which form the blueprint for wiring the brain. Unraveling which specific signals control different aspects of dendritic architecture, such as branching and elongation, pruning and cessation of growth, territory formation, tiling, and self-avoidance requires a quantitative comparison in control and genetically manipulated neurons. The highly conserved shapes of individually identified Drosophila neurons make them well suited for the analysis of dendritic architecture principles. However, to date it remains unclear how tightly dendritic architecture principles of identified central neurons are regulated. This study uses quantitative reconstructions of dendritic architecture of an identified Drosophila flight motoneuron (MN5) with a complex dendritic tree, comprising more than 4,000 dendritic branches and 6 mm total length. MN5 contains a fixed number of 23 dendritic subtrees, which tile into distinct, nonoverlapping volumes of the diffuse motor neuropil. Across-animal comparison and quantitative analysis suggest that tiling of the different dendritic subtrees of the same neuron is caused by competitive and repulsive interactions among subtrees, perhaps allowing different dendritic compartments to be connected to different circuit elements. We also show that dendritic architecture is similar among different wildtype and GAL4 driver fly lines. Metric and topological dendritic architecture features are sufficiently constant to allow for studies of the underlying control mechanisms by genetic manipulations. Dendritic territory and certain topological measures, such as tree compactness, are most constant, suggesting that these reflect the intrinsic molecular identity of the neuron. J. Comp. Neurol. 518:2169-2185, 2010. (c) 2010 Wiley-Liss, Inc.
不同类型的神经元可以通过其树突的特定靶向位置和分支模式来区分，这些树突构成了大脑布线的蓝图。要弄清楚哪些特定信号控制树突结构的不同方面，如分支和伸长、修剪和生长停止、区域形成、平铺和自我回避，需要在对照神经元和基因操作的神经元之间进行定量比较。果蝇中个体可识别的神经元具有高度保守的形状，这使其非常适合用于分析树突结构原理。然而，迄今为止，尚不清楚已识别的中枢神经元的树突结构原理受到何种程度的严格调控。本研究对果蝇中一个已识别的具有复杂树突树的飞行运动神经元（MN5）的树突结构进行了定量重建，该树突树包含超过4000个树突分支，总长度为6毫米。MN5包含固定数量的23个树突亚树，它们平铺在弥散运动神经纤维网的不同、不重叠区域。跨动物比较和定量分析表明，同一神经元的不同树突亚树的平铺是由亚树之间的竞争性和排斥性相互作用引起的，这可能使得不同的树突隔室能够连接到不同的电路元件。我们还表明，不同的野生型和GAL4驱动果蝇品系之间的树突结构相似。树突结构的度量和拓扑特征足够恒定，从而能够通过基因操作研究其潜在的控制机制。树突区域和某些拓扑测量指标，如树的紧凑性，最为恒定，这表明这些反映了神经元的内在分子特性。《比较神经学杂志》518:2169 - 2185，2010年。（c）2010威利 - 利斯公司。
