Downregulation of Notch mediates the seamless transition of individual Drosophila neuroepithelial progenitors into optic medullar neuroblasts during prolonged G1
Downregulation of Notch mediates the seamless transition of individual Drosophila neuroepithelial progenitors into optic medullar neuroblasts during prolonged G1
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DOI：
10.1016/j.ydbio.2010.12.044
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发表时间：
2011-03-01
影响因子：
2.7
通讯作者：
Okano, Hideyuki
中科院分区：
文献类型：
--
作者：
Orihara-Ono, Minako;Toriya, Masako;Okano, Hideyuki
果蝇视神经原基发育的第一步是对称分裂的神经上皮细胞（内斯）的扩增，然后是不对称分裂的神经母细胞（NBs）的出现。然而，负责从内斯到NB的变化的机制仍然不清楚。在这里，我们进行了详细的分析，证明个别内斯转换为NB。我们还表明，这种转变发生在一个延长的G1阶段。在此G1期，各柱状NE的形态特征和基因表达发生动态变化。一旦NE到NB的转变完成，前NE改变其细胞周期行为，开始不对称分裂。我们还发现Notch信号通路在过渡前被激活，并迅速下调。此外，在靠近内侧边缘的NE区域中Notch野生拷贝的克隆丢失引起Delta的异位积累，导致转变的过早开始。总之，这些发现表明，在有限窗口期间Notch信号传导的激活协调NE到NB转变的适当定时。(C)2011年由Elsevier Inc.出版
The first step in the development of the Drosophila optic medullar primordia is the expansion of symmetrically dividing neuroepithelial cells (NEs); this step is then followed by the appearance of asymmetrically dividing neuroblasts (NBs). However, the mechanisms responsible for the change from NEs to NBs remain unclear. Here, we performed detailed analyses demonstrating that individual NEs are converted into NBs. We also showed that this transition occurs during an elongated G1 phase. During this G1 phase, the morphological features and gene expressions of each columnar NE changed dynamically. Once the NE-to-NB transition was completed, the former NE changed its cell-cycling behavior, commencing asymmetric division. We also found that Notch signaling pathway was activated just before the transition and was rapidly downregulated. Furthermore, the clonal loss of the Notch wild copy in the NE region near the medial edge caused the ectopic accumulation of Delta, leading to the precocious onset of transition. Taken together, these findings indicate that the activation of Notch signaling during a finite window coordinates the proper timing of the NE-to-NB transition. (C) 2011 Published by Elsevier Inc.