Mechanisms that underlie Drosophila visual center

果蝇视觉中枢的机制

基本信息

批准号：
17370077
负责人：
TABATA Tetsuya
金额：
$ 9.41万
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：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17370077/
关键词：
Drosophila visual center medulla proneural wave DWnt4 Sim JAK STAT Focal adhesion kinase proneural gene Notch 視神経投射 Ras CdGAP DFAK

项目摘要

In Drosophila, photoreceptor cells topographically send their axons to the lamina and medulla ganglia.We found :1. DPP signaling mediates the maturation of the lamina glia required for the correct R axon projection pattern by controlling the expression of gcm.2. In DWnt4 mutants, ventral retinal axons misproject 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. Genetic analyses on Wnt signaling components suggest direct roles of DWnt4 for retinal axon guidance.3. 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. The data reveal a novel mechanism for regulation of the interaction between axons and neuronal cell bodies that establishes precise neuronal networks.4. R axons innervate optic ganglia through the tubular structure called the optic stalk, which consists of surface glia (SG). The optic stalk is formed autonomously, independently of R axon projection. We found Fak56D, encoding a Focal adhesion kinase (FAK) and CdGAPr play an important role in forming the optic stalk.5. Medulla neuroblasts develop sequentially in a spatially defined manner, and that lethal of scute (l(1)sc), one of the proneural genes, signals the transition of neuroepithelium to neuroblasts. L(1)sc expression is transient, progressing in a synchronized and ordered "proneural wave" that sweeps toward more lateral NE cells. L(1)sc expression is sufficient to induce NBs and is necessary for timely onset of NB differentiation. We also found that JAK/STAT signaling is activated in NE cells and negatively regulates proneural wave progression.

在果蝇中，感光细胞按地形将轴突发送到椎板和髓质神经节。我们发现：1。 DPP 信号传导通过控制 gcm.2 的表达来介导正确的 R 轴突投射模式所需的层状胶质细胞的成熟。在 DWnt4 突变体中，腹侧视网膜轴突错误投射到背侧薄片。 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。 Wnt信号成分的遗传分析表明DWnt4对视网膜轴突引导具有直接作用。3． R 轴突通过传递诱导信号 Hedgehog (Hh) 触发层神经元的增殖和分化。我们发现 bHLH-PAS 转录因子 Single-thought (Sim) 是由 Hh 在层层神经元中诱导的，并且是层层神经元与 R 轴突关联所必需的。在模拟突变大脑中，层神经元无法与 R 轴突关联。这些数据揭示了一种调节轴突和神经元细胞体之间相互作用的新机制，从而建立精确的神经元网络。4． R 轴突通过称为视柄的管状结构支配视神经节，视柄由表面神经胶质 (SG) 组成。视柄自主形成，独立于 R 轴突投影。我们发现编码粘着斑激酶(FAK)的Fak56D和CdGAPr在视柄的形成中发挥着重要作用。5．髓质神经母细胞以空间定义的方式顺序发育，前神经基因之一盾片 (l(1)sc) 的致死标志着神经上皮向神经母细胞的转变。 L(1)sc 表达是短暂的，以同步且有序的“前神经波”的形式进行，扫向更多的外侧 NE 细胞。 L(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。我们还发现 JAK/STAT 信号在 NE 细胞中被激活并负向调节原神经波进展。