Gap junctions are physical channels that connect adjacent cells, permitting the flow of small molecules/ions between the cytoplasms of the coupled units. Innexin/innexin-like proteins are responsible for the formation of invertebrate gap junctions. Within the nervous system, gap junctions often function as electrical synapses, providing a means for coordinating activity among electrically coupled neurons. While some gap junctions allow the bidirectional flow of small molecules/ions between coupled cells, others permit flow in one direction only or preferentially. The complement of innexins present in a gap junction determines its specific properties. Thus, understanding innexin diversity is key for understanding the full potential of electrical coupling in a species/system. The decapod crustacean cardiac ganglion (CG), which controls cardiac muscle contractions, is a simple pattern-generating neural network with extensive electrical coupling among its circuit elements. In the lobster, Homarus americanus, prior work suggested that the adult neuronal innexin complement consists of six innexins (Homam-Inx1-4 and Homam-Inx6-7). Here, using a H. americanus CG-specific transcriptome, we explored innexin complement in this portion of the lobster nervous system. With the exception of Homam-Inx4, all of the previously described innexins appear to be expressed in the H. americanus CG. In addition, transcripts encoding seven novel putative innexins (Homam-Inx8-14) were identified, four (Homam-Inx8-11) having multiple splice variants, e.g., six for Homam-Inx8. Collectively, these data indicate that the innexin complement of the lobster nervous system in general, and the CG specifically, is likely significantly greater than previously reported, suggesting the possibility of expanded gap junction diversity and function in H. americanus.

中文翻译：

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计算机分析表明，龙虾的美洲大戟的神经节含有各种各样的推定的内毒素/内毒素样蛋白，包括该蛋白家族的已知成员和新成员。

间隙连接是连接相邻细胞的物理通道，允许小分子/离子在偶联单位的细胞质之间流动。Innexin / innexin样蛋白负责无脊椎动物间隙连接的形成。在神经系统内，间隙连接通常起电突触的作用，为协调电耦合神经元之间的活动提供了一种手段。虽然一些间隙连接允许小分子/离子在耦合的细胞之间双向流动，但其他的间隙连接则仅允许一个方向或优先进行一个方向的流动。间隙连接中存在的内毒素的互补决定了其特异性。因此，了解内毒素多样性对于了解物种/系统中电耦合的全部潜力至关重要。十足纲甲壳类心脏神经节（CG），控制心肌收缩的是一个简单的模式生成神经网络，其电路元件之间具有广泛的电耦合。在龙虾中美洲大螯虾，以前的工作表明，成人神经元内毒素补体由六种内毒素组成（Homam-Inx1-4和Homam-Inx6-7）。在这里，我们使用美国H. CG特异的转录组，研究了龙虾神经系统这一部分的内毒素补体。除了Homam-Inx4，所有先前描述的内毒素似乎都在美洲嗜血杆菌中表达CG。另外，鉴定出编码7种新型推定的神经毒素（Homam-Inx8-14）的转录物，其中4种（Homam-Inx8-11）具有多种剪接变体，例如6种对于Homam-Inx8。总体而言，这些数据表明，一般来说，龙虾神经系统的内毒素补体，特别是CG可能显着大于以前报道的水平，这表明扩大了美国嗜血杆菌的间隙连接多样性和功能的可能性。