TDP-43 binds and transports G-quadruplex-containing mRNAs into neurites for local translation
TDP-43 binds and transports G-quadruplex-containing mRNAs into neurites for local translation
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DOI：
10.1111/gtc.12352
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发表时间：
2016-05-01
期刊：
影响因子：
2.1
通讯作者：
Ishihama, Akira
中科院分区：
文献类型：
--
作者：
Ishiguro, Akira;Kimura, Nobuyuki;Ishihama, Akira
神经突的生长和分化取决于一组特定 mRNA 到限制区域的长距离运输及其局部翻译。在这里，我们发现大小为 43kDa 的 TAR DNA 结合蛋白 (TDP-43) 在 mRNA 的细胞内转运中发挥着重要作用。为了鉴定 TDP-43 识别的靶 RNA，我们纯化了可溶二聚体形式的 TDP-43，并通过指数富集 (SELEX) 筛选进行配体的体外系统进化。发现所有 TDP-43 结合的 RNA 均含有 G-四链体 (G4)。使用双荧光探针系统，发现含有 G4 的 RNA 与 TDP-43 一起被转运到远端神经突中。两条证据表明，TDP-43 功能丧失会导致神经退行性疾病：(i) 肌萎缩侧索硬化症 (ALS) 相关突变体 TDP-43(M337V) 缺乏结合和转运含 G4 mRNA 的活性； (ii) 含有来自 ALS 连接的 C9orf72 基因的 G4 形成 GGGGCC 重复扩增的 RNA 吸收 TDP-43，从而减少细胞内功能性 TDP-43 池。综上所述，我们认为神经元内的 TDP-43 在 mRNA 转运到远端神经突进行局部翻译方面发挥着重要作用，因此，TDP-43 功能障碍会导致 ALS 和额颞叶变性等神经疾病。
Growth and differentiation of the neurites depends on long-distance transport of a specific set of mRNAs to restricted area and their local translation. Here, we found that a TAR DNA-binding protein of 43kDa in size (TDP-43) plays an essential role in intracellular transport of mRNA. For identification of target RNAs recognized by TDP-43, we purified TDP-43 in soluble dimer form and subjected to invitro systematic evolution of ligands by exponential enrichment (SELEX) screening. All the TDP-43-bound RNAs were found to contain G-quadruplex (G4). Using a double-fluorescent probe system, G4-containing RNAs were found to be transported, together with TDP-43, into the distal neurites. Two lines of evidence indicated that loss of function of TDP-43 results in the neurodegenerative disorder: (i) amyotrophic lateral sclerosis (ALS)-linked mutant TDP-43(M337V) lacks the activity of binding and transport of G4-containing mRNAs; and (ii) RNA containing G4-forming GGGGCC repeat expansion from the ALS-linked C9orf72 gene absorbs TDP-43, thereby reducing the intracellular pool of functional TDP-43. Taken together, we propose that TDP-43 within neurons plays an essential role of mRNA transport into distal neurites for local translation, and thus, dysfunctions of TDP-43 cause neural diseases such as ALS and frontotemporal lobar degeneration.