A temporal mechanism that produces neuronal diversity in the Drosophila visual center
A temporal mechanism that produces neuronal diversity in the Drosophila visual center
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DOI：
10.1016/j.ydbio.2013.05.002
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发表时间：
2013-08-01
影响因子：
2.7
通讯作者：
Sato, Makoto
中科院分区：
文献类型：
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作者：
Suzuki, Takumi;Kaido, Masako;Sato, Makoto
大脑由神经干细胞产生的各种类型的神经元组成；然而，神经元多样性背后的机制仍然不确定。最近的一项研究表明，作为果蝇视叶的最大组成部分，延髓是适合脑发育的模型系统，因为它与哺乳动物的大脑具有相同的结构特征，并且由适中数量和各种类型的神经元组成。延髓原基中的同心圆带对应于延髓神经元的类型，其特征是四种转录因子的表达，包括同胸(HTH)、脑特定同源盒(BSH)、Run(Run)和Difter(DRF)。在这里，我们研究了在时间上决定延髓原基神经元类型的机制。为此，我们搜索了在髓神经母细胞(NBS，神经干细胞样神经前体细胞)的子集中瞬时表达的转录因子，并确定了五个候选基因(HTH、KLumpfuss(Klu)、无眼(Ey)、疏松配对(Sip)和Dichaete(D))。遗传学实验结果至少解释了转录因子在NBS中表达的时间变化，其顺序为Ey、Sip和D。我们的结果还表明，NBS中HTH、Klu和Ey的表达分别触发了HTH/BSH-、RUN和DRF阳性神经元的产生。这些结果表明，延髓神经元的类型是以出生顺序依赖的方式指定的，由NBS中顺序表达的时间转录因子的作用决定。(C)2013 Elsevier Inc.保留所有权利。
The brain consists of various types of neurons that are generated from neural stem cells; however, the mechanisms underlying neuronal diversity remain uncertain. A recent study demonstrated that the medulla, the largest component of the Drosophila optic lobe, is a suitable model system for brain development because it shares structural features with the mammalian brain and consists of a moderate number and various types of neurons. The concentric zones in the medulla primordium that are characterized by the expression of four transcription factors, including Homothorax (Hth), Brain-specific homeobox (Bsh), Runt (Run) and Drifter (Drf), correspond to types of medulla neurons. Here, we examine the mechanisms that temporally determine the neuronal types in the medulla primordium. For this purpose, we searched for transcription factors that are transiently expressed in a subset of medulla neuroblasts (NBs, neuronal stem cell-like neural precursor cells) and identified five candidates (Hth, Klumpfuss (Klu), Eyeless (Ey), Sloppy paired (Sip) and Dichaete (D)). The results of genetic experiments at least explain the temporal transition of the transcription factor expression in NBs in the order of Ey, Sip and D. Our results also suggest that expression of Hth, Klu and Ey in NBs trigger the production of Hth/Bsh-, Run- and Drf-positive neurons, respectively. These results suggest that medulla neuron types are specified in a birth order-dependent manner by the action of temporal transcription factors that are sequentially expressed in NBs. (c) 2013 Elsevier Inc. All rights reserved.