N6-methyladenosine mRNA marking promotes selective translation of regulons required for human erythropoiesis [RNA-Seq]

Many of the regulatory features governing erythrocyte specification, maturation, and associated disorders remain enigmatic. To identify new regulators of erythropoiesis, we performed a functional genomic screen for genes affecting expression of the erythroid marker CD235a/GYPA. Among validating hits were genes coding for the N6-methyladenosine (m6A) mRNA methyltransferase (MTase) complex, including, METTL14, METTL3, and WTAP. We found that m6A MTase activity promotes erythroid gene expression programs through selective translation of ~300 m6A marked mRNAs, including those coding for SETD histone methyltransferases, ribosomal components, and polyA RNA binding proteins, and novel genes. Remarkably, loss of m6A marks resulted in dramatic loss of H3K4me3 marks across key erythroid-specific KLF1 transcriptional targets (e.g., Heme biosynthesis genes). Further, each m6A MTase subunit and a subset of their mRNAs targets are required for human erythroid specification in primary bone-marrow derived progenitors. Thus, m6A mRNA marks promote the translation of a network of genes required for human erythropoiesis. series of gene KOs

调控红细胞特化、成熟及相关疾病的诸多遗传学调控机制仍尚不明确。为鉴定红细胞生成的新型调控因子，我们针对影响红细胞标志物CD235a/GYPA表达的基因开展了功能基因组筛选。经验证的阳性命中基因包括编码N6-甲基腺嘌呤（N6-methyladenosine, m6A）mRNA甲基转移酶（methyltransferase, MTase）复合物的基因，即METTL14、METTL3与WTAP。研究发现，m6A甲基转移酶活性可通过对约300个带有m6A标记的mRNA进行选择性翻译，进而激活红细胞相关基因表达程序，其编码产物涵盖SETD家族组蛋白甲基转移酶、核糖体组分、polyA RNA结合蛋白以及新型功能基因。值得注意的是，m6A标记的缺失会导致关键红细胞特异性KLF1（Krüppel样转录因子1）转录靶标区域（如血红素生物合成基因）的H3K4me3组蛋白修饰标记显著丢失。进一步实验证实，每个m6A甲基转移酶亚基及其部分mRNA靶标，对于原代骨髓来源祖细胞的人红细胞特化过程不可或缺。综上，mRNA上的m6A修饰标记可促进人类红细胞生成所需基因调控网络的翻译。系列基因敲除实验