Memory and learning involve activity-driven expression of proteins and cytoskeletal reorganization at new synapses, requiring posttranscriptional regulation of localized mRNA a long distance from corresponding nuclei. A key factor expressed early in synapse formation is Msp300/Nesprin-1, which organizes actin filaments around the new synapse. How Msp300 expression is regulated during synaptic plasticity is poorly understood. Here, we show that activity-dependent accumulation of Msp300 in the postsynaptic compartment of theDrosophila larval neuromuscular junction is regulated by the conserved RNA binding protein Syncrip/hnRNP Q. Syncrip (Syp) binds tomsp300 transcripts and is essential for plasticity. Single-molecule imaging shows that msp300 is associated with Syp in vivo and forms ribosome-rich granules that contain the translation factor eIF4E. Elevated neural activity alters the dynamics of Syp and the number ofmsp300:Syp:eIF4E RNP granules at the synapse, suggesting that these particles facilitate translation. These results introduce Syp as an important early acting activity-dependent regulator of a plasticity gene that is strongly associated with human ataxias.

中文翻译：

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Syncrip/hnRNP Q 是活动诱导的 Msp300/Nesprin-1 表达和新突触形成所必需的

记忆和学习涉及活动驱动的蛋白质表达和新突触处的细胞骨架重组，需要对距相应细胞核较远的局部 mRNA 进行转录后调节。突触形成早期表达的一个关键因子是 Msp300/Nesprin-1，它在新突触周围组织肌动蛋白丝。Msp300 表达在突触可塑性过程中如何受到调节尚不清楚。在这里，我们表明，Msp300 在果蝇幼虫神经肌肉接头突触后区室中的活动依赖性积累受到保守的 RNA 结合蛋白 Syncrip/hnRNP Q 的调节。Syncrip (Syp) 结合 tomsp300 转录本，对于可塑性至关重要。单分子成像显示 msp300 在体内与 Syp 相关，并形成富含核糖体的颗粒，其中含有翻译因子 eIF4E。神经活动的升高改变了 Syp 的动力学和突触处 msp300:Syp:eIF4E RNP 颗粒的数量，表明这些颗粒有助于翻译。这些结果表明 Syp 是可塑性基因的一种重要的早期作用活性依赖性调节因子，与人类共济失调密切相关。