m6a methylation drives IMP1 regulation during human neuronal differentiation [miCLIP]

Human neurodevelopment requires differentiating neurons to establish large networks of connections in a highly stereotyped manner. Neuronal differentiation in particular requires RNA-binding proteins to spatiotemporally regulate thousands of different mRNAs. Yet how these proteins precisely relate to neuronal development and coordinate the expression of functionally coherent genes in a cell type specific manner is only partially understood. To address this, we sought to clarify how the paradigmatic RNA-binding protein IMP1/IGF2BP1, an essential developmental factor, selects and regulates its RNA targets transcriptome-wide during the differentiation of human pluripotent stem cell-derived neural precursor cells to their neuronal counterparts. We used a combination of systemic and molecular analyses to show that IMP1 directly binds to and regulates the expression of a large sets of mRNAs. Overall design: miCLIP on IPSC-derived NPC and neurons

人类神经发育过程中，分化中的神经元需以高度定型化的模式构建大规模神经元连接网络。尤为关键的是，神经元分化需要RNA结合蛋白（RNA-binding protein）在时空特异性地调控数千种不同的信使RNA（messenger RNA, mRNA）。然而，此类蛋白质如何精准关联神经元发育，并以细胞类型特异性的方式协调功能协同基因的表达，目前仅得到部分阐释。为解决这一科学问题，本研究旨在阐明典型RNA结合蛋白IMP1/IGF2BP1——一种至关重要的发育调控因子——在人类多能干细胞诱导的神经前体细胞（neural precursor cell, NPC）向神经元分化的过程中，如何在全转录组范围内筛选并调控其RNA靶标。本研究结合系统性与分子生物学分析手段，证实IMP1可直接结合并调控大量mRNA的表达。实验整体设计：对诱导多能干细胞（induced pluripotent stem cell, iPSC）来源的神经前体细胞（NPC）及神经元开展miCLIP实验。