Synaptic activity mediates information storage and memory consolidation in the brain and requires a fast de novo synthesis of mRNAs in the nucleus and proteins in synapses. Intracellular localization of a protein can be achieved by mRNA trafficking and localized translation. Activity-regulated cytoskeleton-associated protein (Arc) is a master regulator of synaptic plasticity and plays an important role in controlling large signaling networks implicated in learning, memory consolidation, and behavior. Transcription of the Arc gene may be induced by a short behavioral event, resulting in synaptic activation. Arc mRNA is exported into the cytoplasm and can be trafficked into the dendrite of an activated synapse where it is docked and translated. The structure of Arc is similar to the viral GAG (group-specific antigen) protein, and phylogenic analysis suggests that Arc may originate from the family of Ty3/Gypsy retrotransposons. Therefore, Arc might evolve through “domestication” of retroviruses. Arc can form a capsid-like structure that encapsulates a retrovirus-like sentence in the 3-UTR (untranslated region) of Arc mRNA. Such complex can be loaded into extracellular vesicles and transported to other neurons or muscle cells carrying not only genetic information but also regulatory signals within neuronal networks. Therefore, Arc mRNA inter- and intramolecular trafficking is essential for the modulation of synaptic activity required for memory consolidation and cognitive functions. Recent studies with single-molecule imaging in live neurons confirmed and extended the role of Arc mRNA trafficking in synaptic plasticity.

中文翻译：

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神经系统中的 mRNA 贩运：活性调节细胞骨架相关蛋白 (Arc) 参与突触可塑性的关键机制

突触活动介导大脑中的信息存储和记忆巩固，并且需要快速从头合成细胞核中的 mRNA 和突触中的蛋白质。蛋白质的细胞内定位可以通过 mRNA 运输和本地化翻译来实现。活动调节的细胞骨架相关蛋白 (Arc) 是突触可塑性的主要调节因子，在控制与学习、记忆巩固和行为有关的大型信号网络中发挥重要作用。Arc基因的转录可能由短暂的行为事件诱导，导致突触激活。弧mRNA 被输出到细胞质中，并且可以被运输到激活的突触的树突中，在那里它被对接和翻译。Arc 的结构与病毒 GAG（组特异性抗原）蛋白相似，系统发育分析表明 Arc 可能起源于 Ty3/Gypsy 反转录转座子家族。因此，Arc 可能通过逆转录病毒的“驯化”而进化。Arc 可以形成衣壳样结构，在Arc mRNA的 3 - UTR（非翻译区）中包裹了一个类似逆转录病毒的句子。这种复合物可以装载到细胞外囊泡中，并运输到其他神经元或肌肉细胞，这些神经元或肌肉细胞不仅携带遗传信息，还携带神经元网络内的调节信号。因此，弧mRNA 分子间和分子内运输对于调节记忆巩固和认知功能所需的突触活动至关重要。最近在活神经元中进行的单分子成像研究证实并扩展了Arc mRNA 运输在突触可塑性中的作用。