Self-avoidance, the tendency of neurites of the same cell to selectively avoid each other, is a property of both vertebrate and invertebrate neurons. In Drosophila, self-avoidance is mediated by a large family of cell recognition molecules of the immunoglobulin superfamily encoded, via alternative splicing, by the Dscam1 locus. Dscam1 promotes self-avoidance in dendrites, axons, and prospective postsynaptic elements. Expression analysis suggests that each neuron expresses a unique combination of isoforms. Identical isoforms on sister neurites exhibit isoform-specific homophilic recognition and elicit repulsion between processes, thereby promoting self-avoidance. Although any isoform can promote self-avoidance, thousands are necessary to ensure that neurites readily discriminate between self and nonself. Recent studies indicate that a large family of cadherins in the mouse, i.e., the clustered protocadherins, functions in an analogous fashion to promote self-avoidance. These studies argue for the evolution of a common molecular strategy for self-avoidance.

中文翻译：

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自我回避的分子基础。

自我回避，同一细胞的神经突有选择地相互回避的倾向，是脊椎动物和无脊椎动物神经元的特性。在果蝇中，自我回避是由 Dscam1 基因座通过选择性剪接编码的免疫球蛋白超家族的一大类细胞识别分子介导的。Dscam1 促进树突、轴突和预期突触后元件的自我回避。表达分析表明每个神经元都表达一种独特的异构体组合。姐妹神经突上的相同同种型表现出同种型特异性的同质性识别并引起过程之间的排斥，从而促进自我回避。尽管任何同工型都可以促进自我回避，但需要数千个异构体来确保神经突轻松区分自我和非自我。最近的研究表明，小鼠中的一大类钙粘蛋白，即聚集的原钙粘蛋白，以类似的方式发挥作用，以促进自我回避。这些研究主张进化出一种常见的自我回避分子策略。