Department of Microbiology, Oslo University Hospital, Rikshospitalet, NO-0027, Oslo, Norway.
Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, NO-0317, Oslo, Norway.
Genome Biol. 2018 May 31;19(1):69. doi: 10.1186/s13059-018-1436-y.
N -methyladenosine (mA) modification in mRNAs was recently shown to be dynamically regulated, indicating a pivotal role in multiple developmental processes. Most recently, it was shown that the Mettl3-Mettl14 writer complex of this mark is required for the temporal control of cortical neurogenesis. The mA reader protein Ythdf2 promotes mRNA degradation by recognizing mA and recruiting the mRNA decay machinery.
We show that the conditional depletion of the mA reader protein Ythdf2 in mice causes lethality at late embryonic developmental stages, with embryos characterized by compromised neural development. We demonstrate that neural stem/progenitor cell (NSPC) self-renewal and spatiotemporal generation of neurons and other cell types are severely impacted by the loss of Ythdf2 in embryonic neocortex. Combining in vivo and in vitro assays, we show that the proliferation and differentiation capabilities of NSPCs decrease significantly in Ythdf2 embryos. The Ythdf2 neurons are unable to produce normally functioning neurites, leading to failure in recovery upon reactive oxygen species stimulation. Consistently, expression of genes enriched in neural development pathways is significantly disturbed. Detailed analysis of the mA-methylomes of Ythdf2 NSPCs identifies that the JAK-STAT cascade inhibitory genes contribute to neuroprotection and neurite outgrowths show increased expression and mA enrichment. In agreement with the function of Ythdf2, delayed degradation of neuron differentiation-related mA-containing mRNAs is seen in Ythdf2 NSPCs.
We show that the mA reader protein Ythdf2 modulates neural development by promoting mA-dependent degradation of neural development-related mRNA targets.
最近的研究表明，mRNA 中的 N 6 -甲基腺苷（m6A）修饰是动态调控的，这表明其在多种发育过程中起着关键作用。最近的研究表明，这种标记的 Mettl3-Mettl14 写入复合物对于皮质神经发生的时间控制是必需的。m6A 读取蛋白 Ythdf2 通过识别 m6A 并募集 mRNA 降解机制来促进 mRNA 的降解。
我们表明，在小鼠中条件性耗尽 m6A 读取蛋白 Ythdf2 会导致胚胎晚期发育阶段的致死性，胚胎表现出神经发育受损。我们证明，神经干细胞/祖细胞（NSPC）的自我更新和时空产生神经元和其他细胞类型受到胚胎新皮质中 Ythdf2 缺失的严重影响。通过体内和体外测定相结合，我们表明 Ythdf2 胚胎中 NSPC 的增殖和分化能力显著降低。Ythdf2 神经元无法产生正常功能的神经突，导致在活性氧刺激下恢复失败。一致地，富含神经发育途径的基因的表达显著受到干扰。对 Ythdf2 NSPC 的 m6A 甲基组学的详细分析表明，JAK-STAT 级联抑制基因有助于神经保护和神经突生长，表现出增加的表达和 m6A 富集。与 Ythdf2 的功能一致，在 Ythdf2 NSPC 中观察到与神经元分化相关的 m6A 包含的 mRNA 的降解延迟。
我们表明，m6A 读取蛋白 Ythdf2 通过促进与神经发育相关的 m6A 依赖性降解 mRNA 靶标来调节神经发育。
