Studies on developmental mechanisms of the Drosophila visual center

果蝇视觉中枢发育机制的研究

基本信息

批准号：
15370093
负责人：
TABATA Tetsuya
金额：
$ 9.86万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15370093/
关键词：
Drosophila visual center R axon lamina neuron Dpp DWnt4 Hedgehog Sim 視覚系 b-HLH-PAS BMP 軸策投射 Notch Wnt

项目摘要

In Drosophila, photoreceptor cells topographically send their axons to the first optic ganglion, the lamina. 1.dpp is expressed at the margin of the lamina target region, where glial precursors reside. Inhibition of DPP signaling in this region resulted in defects in the differentiation of the lamina glial cells. Expression of glial cells missing (gcm) depends on DPP. In addition, R axon projections and lamina glia development were impaired by the expression of a dominant-negative form of gcm, suggesting that gcm controls the differentiation of lamina glial cells. These results suggest that DPP signaling mediates the maturation of the lamina glia required for the correct R axon projection pattern by controlling the expression of gcm. 2.R axons trigger proliferation and differentiation of lamina neurons by delivering the inductive signal, Hedgehog(Hh). We found that the bHLH-PAS transcription factor Single-minded (Sim) is induced by Hh in the lamina neurons and is required for the association of lamina neurons with R axons. In sim mutant brains, lamina neurons fail to associate with R axons. As a result, lamina neurons are set aside from R axons. The data reveal a novel mechanism for regulation of the interaction between axons and neuronal cell bodies that establishes precise neuronal networks. 3. In DWnt4 mutants, ventral retinal axons misprojected to the dorsal lamina. DWnt4 is normally expressed in the ventral half of the developing lamina and DWnt4 protein was detected along ventral retinal axons. Dfrizzled2 and dishevelled, respectively, encode a receptor and a signaling molecule required for Wnt signaling. Mutations in both genes caused DWnt4-like defects, and were autonomously required in the retina, suggesting direct roles of DWnt4 for retinal axon guidance. In contrast, iroquois homeobox genes are the dorsal cues for the retina.

在果蝇中，感光细胞在地形上将其轴突发送到第一个光学神经节薄片。 1.DPP在层层靶区域的边缘表达，那里的神经胶质前体居住。该区域中DPP信号传导的抑制导致椎板胶质细胞分化的缺陷。神经胶质细胞缺失（GCM）的表达取决于DPP。此外，R轴突投影和椎板胶质神经胶质发育受到GCM的显性阴性形式的表达损害，这表明GCM控制着椎板胶质细胞的分化。这些结果表明，DPP信号传导通过控制GCM的表达来介导正确的R轴突投影模式所需的层状胶质神经胶质。 2. R轴突通过传递电感信号刺猬（HH）触发椎板神经元的扩散和分化。我们发现，lamina神经元中HH诱导HH诱导BHLH-PAS转录因子（SIM），这对于椎板神经元与R轴突的关联是必需的。在SIM突变大脑中，椎板神经元无法与R轴突相连。结果，将椎板神经元放在R轴突上。数据揭示了一种新的机制来调节轴突和神经元细胞体之间建立精确神经元网络的相互作用。 3。在DWNT4突变体中，腹侧视网膜轴突误射到背层。 DWNT4通常在发育中的椎板的腹侧一半中表达，并且沿腹侧视网膜轴突检测到DWNT4蛋白。 dfrizzled2和Dishevelvevel，分别编码WNT信号所需的受体和信号分子。这两个基因的突变引起了DWNT4样缺陷，并且在视网膜中自主需要，这表明DWNT4在视网膜轴突引导中直接作用。相比之下，易洛魁族同源基因是视网膜的背线。