Dscam2 mediates axonal tiling in the Drosophila visual system
Dscam2 mediates axonal tiling in the Drosophila visual system
复制标题
DOI：
10.1038/nature05855
复制
发表时间：
2007-06-07
期刊：
影响因子：
64.8
通讯作者：
Zipursky, S. Lawrence
中科院分区：
文献类型：
--
作者：
Millard, S. Sean;Flanagan, John J.;Zipursky, S. Lawrence
脊椎动物和无脊椎动物大脑中的感觉处理中心通常被组织成重复的列，从而促进外部世界的内部地形表示。每一列中的细胞都以一种固定的方式排列，并在离散层中形成精确的突触连接模式。这些连接在很大程度上局限于单个列，从而保留了来自外围的空间信息。其他神经元通过连接到多个列来整合这些信息。将轴突限制在圆柱上在概念上类似于平铺。同一类别的相邻神经元的轴突和树突使用平铺来形成完整但不重叠的感受野（1-3）。据认为，在分子水平上，细胞表面蛋白质通过接触依赖性排斥相互作用介导平铺（1，2，4，5），但蛋白质服务这一功能尚未被确定。在这里，我们表明，免疫球蛋白超家族成员Dscam 2限制L1板神经元形成的连接，在果蝇视觉系统的列。我们的数据支持一个模型，其中Dscam 2亲同性相互作用介导的L1细胞的神经突在相邻列之间的排斥。我们认为Dscam 2是L1神经元的平铺受体。
Sensory processing centres in both the vertebrate and the invertebrate brain are often organized into reiterated columns, thus facilitating an internal topographic representation of the external world. Cells within each column are arranged in a stereotyped fashion and form precise patterns of synaptic connections within discrete layers. These connections are largely confined to a single column, thereby preserving the spatial information from the periphery. Other neurons integrate this information by connecting to multiple columns. Restricting axons to columns is conceptually similar to tiling. Axons and dendrites of neighbouring neurons of the same class use tiling to form complete, yet non-overlapping, receptive fields(1-3). It is thought that, at the molecular level, cell-surface proteins mediate tiling through contact-dependent repulsive interactions(1,2,4,5), but proteins serving this function have not yet been identified. Here we show that the immunoglobulin superfamily member Dscam2 restricts the connections formed by L1 lamina neurons to columns in the Drosophila visual system. Our data support a model in which Dscam2 homophilic interactions mediate repulsion between neurites of L1 cells in neighbouring columns. We propose that Dscam2 is a tiling receptor for L1 neurons.