Temporal patterning of neural progenitors in Drosophila.
Temporal patterning of neural progenitors in Drosophila.
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DOI：
10.1016/b978-0-12-396968-2.00003-8
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发表时间：
2013
影响因子：
--
通讯作者：
Desplan, Claude
中科院分区：
文献类型：
--
作者：
Li, Xin;Chen, Zhenqing;Desplan, Claude
果蝇最近已成为一个强大的模型系统，用于理解被称为神经母细胞（NBs）的神经祖细胞的时间模式机制。已发现两种不同的转录因子（TFs）时间序列在两个不同系统的神经母细胞中依次表达：在果蝇腹神经索中的驼背基因（Hunchback）、克鲁佩尔基因（Krüppel）、Pdm1/Pdm2、卡斯特基因（Castor）和颗粒头基因（Grainyhead）序列；以及在延髓神经母细胞中起模式作用的同胸基因（Homothorax）、克伦普福斯基因（Klumpfuss）、无眼基因（Eyeless）、松散配对基因（Sloppy - paired）、双胸基因（Dichaete）和无尾基因（Tailless）序列。此外，II型神经母细胞谱系的中间神经祖细胞由不同的序列模式化：双胸基因、颗粒头基因和无眼基因。这三个例子表明，通过转录因子序列对神经前体进行时间模式化是产生神经多样性的一个常见主题。时间因子之间的交叉调节，包括负反馈调节和正前馈调节，可以促进序列的进展。然而，要理解时间转换的机制仍有许多问题。时间序列的进展与神经母细胞能力的逐渐限制密切相关，并最终决定神经发生的终止。时间特性必须与空间特性信息以及依赖于Notch的二元命运选择相结合，以产生特定的神经元命运。
Drosophila has recently become a powerful model system to understand the mechanisms of temporal patterning of neural progenitors called neuroblasts (NBs). Two different temporal sequences of transcription factors (TFs) have been found to be sequentially expressed in NBs of two different systems: the Hunchback, Krüppel, Pdm1/Pdm2, Castor, and Grainyhead sequence in the Drosophila ventral nerve cord; and the Homothorax, Klumpfuss, Eyeless, Sloppy-paired, Dichaete, and Tailless sequence that patterns medulla NBs. In addition, the intermediate neural progenitors of type II NB lineages are patterned by a different sequence: Dichaete, Grainyhead, and Eyeless. These three examples suggest that temporal patterning of neural precursors by sequences of TFs is a common theme to generate neural diversity. Cross-regulations, including negative feedback regulation and positive feedforward regulation among the temporal factors, can facilitate the progression of the sequence. However, there are many remaining questions to understand the mechanism of temporal transitions. The temporal sequence progression is intimately linked to the progressive restriction of NB competence, and eventually determines the end of neurogenesis. Temporal identity has to be integrated with spatial identity information, as well as with the Notch-dependent binary fate choices, in order to generate specific neuron fates.