947 E 58th St., Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA.
Semin Cell Dev Biol. 2017 Sep;69:151-157. doi: 10.1016/j.semcdb.2017.06.007. Epub 2017 Jun 13.
All animals with large brains must have molecular mechanisms to regulate neuronal process outgrowth and prevent neurite self-entanglement. In vertebrates, two major gene families implicated in these mechanisms are the clustered protocadherins and the atypical cadherins. However, the molecular mechanisms utilized in complex invertebrate brains, such as those of the cephalopods, remain largely unknown. Recently, we identified protocadherins and atypical cadherins in the octopus. The octopus protocadherin expansion shares features with the mammalian clustered protocadherins, including enrichment in neural tissues, clustered head-to-tail orientations in the genome, and a large first exon encoding all cadherin domains. Other octopus cadherins, including a newly-identified cadherin with 77 extracellular cadherin domains, are elevated in the suckers, a striking cephalopod novelty. Future study of these octopus genes may yield insights into the general functions of protocadherins in neural wiring and cadherin-related proteins in complex morphogenesis.
所有具有大型大脑的动物都必须具有调节神经元突起生长和防止神经突自缠结的分子机制。在脊椎动物中，涉及这些机制的两个主要基因家族是聚集原钙黏蛋白和非典型钙黏蛋白。然而，在复杂的无脊椎动物大脑（如头足类动物的大脑）中使用的分子机制在很大程度上仍然未知。最近，我们在章鱼中鉴定了原钙黏蛋白和非典型钙黏蛋白。章鱼原钙黏蛋白的扩张与哺乳动物聚集原钙黏蛋白具有相同的特征，包括富含神经组织、在基因组中头尾聚集的方向以及编码所有钙黏蛋白结构域的大第一个外显子。章鱼的其他钙黏蛋白，包括新鉴定的具有 77 个细胞外钙黏蛋白结构域的钙黏蛋白，在吸盘中升高，这是头足类动物的一个显著新特征。对这些章鱼基因的未来研究可能会深入了解原钙黏蛋白在神经连接中的一般功能以及钙黏蛋白相关蛋白在复杂形态发生中的作用。
