Drosophila optic lobe neuroblasts triggered by a wave of proneural gene expression that is negatively regulated by JAK/STAT
Drosophila optic lobe neuroblasts triggered by a wave of proneural gene expression that is negatively regulated by JAK/STAT
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DOI：
10.1242/dev.019117
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发表时间：
2008-04-15
期刊：
影响因子：
4.6
通讯作者：
Tabata, Tetsuya
中科院分区：
文献类型：
--
作者：
Yasugi, Tetsuo;Umetsu, Daiki;Tabata, Tetsuya
神经干细胞称为成神经细胞（NB）在果蝇胚胎的中枢神经系统中产生各种神经元和神经胶质细胞。这些数量很少的NB选自神经上皮（NE）细胞的区域。在三龄幼虫的视叶中，所有外视原基（OOA）的NE细胞发育成产生成体视觉系统的髓质神经元或板层神经元前体的NB。由于光感受器神经元将其轴突直接投射到相应的板层或髓质神经元，因此必须精确调节板层和髓质神经元的数量。在这里，我们表明，表达的前神经蛋白的致命的盾[L（1）sc]信号的NE细胞的过渡到NBs在OOA。L（1）sc表达是短暂的，以同步和有序的“前神经波”向更外侧的内斯扫过。I（1）sc表达足以诱导NB，并且对于NB分化的及时开始是必需的。因此，前神经波先于并诱导NE细胞向NB的转变。未配对（Upd），JAK/STAT信号通路的配体，在最外侧NE细胞中表达。JAK/STAT信号传导负调节前神经波进展并控制视叶中NB的数量。我们的研究结果表明，NBs可能是平衡的数目与板层神经元的JAK/STAT调节前神经波的进展，从而提供了一个精确的地形图在视觉中心的形成发展基础。
Neural stem cells called neuroblasts (NBs) generate a variety of neuronal and glial cells in the central nervous system of the Drosophila embryo. These NBs, few in number, are selected from a field of neuroepithelial ( NE) cells. In the optic lobe of the third instar larva, all NE cells of the outer optic anlage (OOA) develop into either NBs that generate the medulla neurons or lamina neuron precursors of the adult visual system. The number of lamina and medulla neurons must be precisely regulated because photoreceptor neurons project their axons directly to corresponding lamina or medulla neurons. Here, we show that expression of the proneural protein Lethal of scute [L(1)sc] signals the transition of NE cells to NBs in the OOA. L(1) sc expression is transient, progressing in a synchronized and ordered 'proneural wave' that sweeps toward more lateral NEs. l(1) sc expression is sufficient to induce NBs and is necessary for timely onset of NB differentiation. Thus, proneural wave precedes and induces transition of NE cells to NBs. Unpaired (Upd), the ligand for the JAK/STAT signaling pathway, is expressed in the most lateral NE cells. JAK/STAT signaling negatively regulates proneural wave progression and controls the number of NBs in the optic lobe. Our findings suggest that NBs might be balanced with the number of lamina neurons by JAK/STAT regulation of proneural wave progression, thereby providing the developmental basis for the formation of a precise topographic map in the visual center.