Supplementary Material for: Bioinformatic Analysis Reveals the Distinct Role of 5’UTR-specific m6A RNA Modification in Mice Developing Cerebral Cortices

N6-methyladenosine (m6A) abundantly exists in the cerebral cortex, and is emerging as an essential factor in cortical development and function. As the m6A binding site appears to be dynamically methylated in different RNA regions at the temporal-specific developing stage, it is of value to distinguish the unique character of region- and temporal-specific m6A. Herein, we analyzed the status of temporal-specific m6A within RNA 5’ untranslated region (5’UTR) using m6A-methylated sequencing data and transcriptomic sequencing data from 12.5-13-day embryonic cerebral cortices and 14-day postnatal ones. We identified sorts of RNAs that are uniquely m6A-methylated in the 5’UTR region and sorted them into specific neurological processes. Compared with 3’UTR-m6A-methylated RNAs, 5’UTR-m6A-methylated RNAs showed unique functions and mechanisms in regulating cortical development, especially through the pathway of mRNA transport and surveillance. Moreover, the 5’UTR-specific m6A was associated with neurological disorders as well. The FoxO signaling pathway was then focused by these pathogenic 5’UTR-m6A-methylated RNAs, and explored to be involved in the determination of neurological disorders. Additionally, the 5’UTR-m6A-modification patterns and transcriptional patterns play independent but cohesive roles in the developing cortices. Our study emphasizes the importance of 5’UTR-specific m6A in the developing cortex and provides an informative reference for future studies of 5’UTR-specific m6A in normal cortical development and neurological disorders.

N6-甲基腺嘌呤（N6-methyladenosine，简称m6A）广泛存在于大脑皮层中，正成为皮层发育与功能维持不可或缺的关键调控因子。由于m6A结合位点在发育的时序特异性阶段，于RNA不同区域内呈现动态甲基化特征，因此区分区域特异性与时序特异性m6A的独特属性具有重要研究价值。本研究针对胚胎发育第12.5至13天以及出生后第14天的大脑皮层的m6A甲基化测序数据与转录组测序数据，分析了RNA 5'非翻译区（5’ untranslated region，简称5’UTR）内的时序特异性m6A修饰状态。本研究筛选出一批仅在5'UTR区域发生m6A甲基化的RNA分子，并将其归类至特定的神经生物学过程中。相较于3'UTR区域发生m6A甲基化的RNA，5'UTR区域m6A甲基化的RNA在调控皮层发育过程中展现出独特的功能与调控机制，尤其通过mRNA转运与监视通路发挥作用。此外，5'UTR特异性m6A修饰还与神经系统疾病密切相关。本研究聚焦于上述致病的5'UTR区域m6A甲基化RNA所靶向的FoxO信号通路，并探究发现该通路参与神经系统疾病的发生发展调控。同时，5'UTR区域m6A修饰模式与转录组模式在发育中的大脑皮层内既相互独立又协同发挥作用。本研究凸显了5'UTR特异性m6A修饰在大脑皮层发育过程中的重要性，同时为后续关于正常皮层发育及神经系统疾病中5'UTR特异性m6A的相关研究提供了具有参考价值的理论依据。