A study on the development of the cerebral neocortex using mice with perturbations on the subplate neurons

底板是新皮层中发育最早的一层。层内神经元（SP神经元）被认为对皮层板内神经元的发育起着先导作用。为了阐明这些作用，我计划制造缺乏SP神经元的模型小鼠。早期近端启动子（early proximal promoter， EPP）是髓鞘碱性蛋白基因中golli启动子的一部分，在SP神经元中具有强烈和持续的蛋白表达。已知逆转录caspase-3能在表达它的细胞中引起立即死亡。我计划在EPP的控制下，通过递送反向caspase-3来删除亚板。然而，即使SP神经元数量减少，也会导致小鼠大脑大面积缺陷和过早死亡，这给发育分析带来了困难。然后，我试图干扰SP神经元的放射状神经突发挥的特定功能。组成型活性钙调磷酸酶，是通过缺失钙-钙-多调素调节域构建的，被发现可以抑制神经突的延伸。我试图分析在EPP控制下表达构成活性钙调磷酸酶的小鼠SP神经元的变化及其作用。为了与SP神经元受到干扰的小鼠进行比较，我分析了过量表达白细胞介素-9的转基因小鼠的新皮质发育，发现SP神经元的发育得到了增强。一项关于辨别任务的研究是通过训练转基因小鼠在受到光刺激时触摸面板而不是推杠杆来完成的。转基因小鼠的学习成绩低于具有相同遗传背景的对照组小鼠。我们研制的一种新型单克隆抗体4E1在阿米巴样小胶质细胞中具有特异性免疫反应性。在板下区、中间区和脑室下区，与迁移神经元附着的小胶质细胞具有较强的免疫反应性。这表明小胶质细胞参与了神经元的迁移或神经突的延伸。少

The subplate is a layer that develops earliest in the neocortex. Neurones in the layer (SP neurones) are considered to play pioneering roles for neurones in the cortical plates, which develop later. In order to elucidated these roles, I planed to produce model mice devoid of SP neurones. The early proximal promoter (EPP), a part of golli promoter contained in myelin basic protein gene, was found to drive a strong and sustained expression of proteins in SP neurones. Reverse caspase-3 was known to elicit an immediate death in the cells that express it. I planed to delete the subplate by delivering reverse caspase-3 under the control of EPP. It was found, however, that even diminution of number of SP neurones caused extensive defects of the brain and premature death of mice to make developmental analyzes difficult. I then tried to perturb specific functions of SP neurones played by their radial neurites. Constitutively active calcineurin, which is constructed by deletion of the calcium-ca … More lmodulin regulatory domain of the native calcineurin, was found to suppress extension of neurites. I am trying to analyze changes of SP neurones and their effects in the mice that express constitutively active calcineurin under the control of EPP.In order to compare with the mice whose SP neurones are perturbed, I analyzed neocortical development of transgenic mice expressing excess interleukin-9, in which, I have found, the development of SP neurones is enhanced. A study of discrimination tasks was achieved with the transgenic mice by training them to touch a panel instead of to push lever in response to a light stimulus. The transgenic mice showed a lower achievement level than control mice with the same genetic background.A novel monoclonal antibody 4E1, which we have produced, was found to have a specific immunoreactivity in amoeboid microglia. Strong immunoreactivity was found on microglia attached to migrating neurones in the subplate, intermediate zone and subventricular zone. This suggests that microglia participates in neuronal migration or extension of neurites. Less