Involvement of Hu and heterogeneous nuclear ribonucleoprotein K in neuronal differentiation through p21 mRNA post-transcriptional regulation
Involvement of Hu and heterogeneous nuclear ribonucleoprotein K in neuronal differentiation through p21 mRNA post-transcriptional regulation
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DOI：
10.1074/jbc.m411119200
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发表时间：
2005-04-01
影响因子：
4.8
通讯作者：
Okano, H
中科院分区：
文献类型：
--
作者：
Yano, M;Okano, HJ;Okano, H
Hu家族是一组神经元RNA结合蛋白，在发育的神经系统中神经元分化所需。以前，Hu蛋白已显示通过结合非翻译区（UTR）中的富含AU的元件来增强靶mRNA（如p21（CIP 1））的稳定性和/或翻译。在这项研究中，我们表明，胡诱导p21的表达，细胞周期停滞，和神经元分化的小鼠神经母细胞瘤N1 E-115细胞。在N1 E-115细胞中，p21表达在Me 2SO诱导的分化过程中也被上调，并且通过其3 '-UTR由转录后机制控制。为了研究Hu功能的分子机制，我们使用蛋白质组学策略分离Hu相互作用蛋白并鉴定异质核核糖核蛋白（hnRNP）K。hnRNP K还特异性结合p21 mRNA 3 '-UTR中富含CU的序列，并在非神经元和神经元细胞中抑制其翻译。此外，使用RNA干扰实验，我们表明，Hu-p21通路有助于N1 E-115细胞中神经突生长和增殖的调节，并且该通路被hnRNP K拮抗。我们的研究结果表明，两个RNA结合蛋白，胡和hnRNP K，通过转录后调节p21 mRNA的开关控制的时间从增殖到神经元分化的相互拮抗作用的模型。
The Hu family is a group of neuronal RNA-binding proteins required for neuronal differentiation in the developing nervous system. Previously, Hu proteins have been shown to enhance the stabilization and/or translation of target mRNAs, such as p21 ( CIP1), by binding to AU-rich elements in untranslated regions ( UTRs). In this study, we show that Hu induces p21 expression, cell cycle arrest, and neuronal differentiation in mouse neuroblastoma N1E-115 cells. p21 expression is also up-regulated during Me2SO- induced differentiation in N1E-115 cells and is controlled by post-transcriptional mechanisms through its 3'-UTR. To investigate the molecular mechanisms of Hu functions, we used a proteomics strategy to isolate Hu-interacting proteins and identified heterogeneous nuclear ribonucleoprotein (hnRNP) K. hnRNP K also specifically binds to CU-rich sequences in p21 mRNA 3'-UTR and represses its translation in both nonneuronal and neuronal cells. Further, using RNA interference experiments, we show that the Hu-p21 pathway contributes to the regulation of neurite outgrowth and proliferation in N1E-115 cells, and this pathway is antagonized by hnRNP K. Our results suggest a model in which the mutually antagonistic action of two RNA-binding proteins, Hu and hnRNP K, control the timing of the switch from proliferation to neuronal differentiation through the post-transcriptional regulation of p21 mRNA.