The N6-methyladenosine (m⁶A) modification is the most prevalent post-transcriptional mRNA modification, regulating mRNA decay and splicing. It plays a major role during normal development, differentiation, and disease progression. The modification is regulated by a set of writer, eraser, and reader proteins. The YTH domain family of proteins consists of three homologous m⁶A-binding proteins, Ythdf1, Ythdf2, and Ythdf3, which were suggested to have different cellular functions. However, their sequence similarity and their tendency to bind the same targets suggest that they may have overlapping roles. We systematically knocked out (KO) the Mettl3 writer, each of the Ythdf readers, and the three readers together (triple-KO). We then estimated the effect in vivo in mouse gametogenesis, postnatal viability, and in vitro in mouse embryonic stem cells (mESCs). In gametogenesis, Mettl3-KO severity is increased as the deletion occurs earlier in the process, and Ythdf2 has a dominant role that cannot be compensated by Ythdf1 or Ythdf3, due to differences in readers’ expression pattern across different cell types, both in quantity and in spatial location. Knocking out the three readers together and systematically testing viable offspring genotypes revealed a redundancy in the readers’ role during early development that is Ythdf1/2/3 gene dosage-dependent. Finally, in mESCs there is compensation between the three Ythdf reader proteins, since the resistance to differentiate and the significant effect on mRNA decay occur only in the triple-KO cells and not in the single KOs. Thus, we suggest a new model for the Ythdf readers function, in which there is profound dosage-dependent redundancy when all three readers are equivalently coexpressed in the same cell types.

中文翻译：

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Ythdf m6A 阅读器蛋白之间的上下文相关功能补偿。


N6-甲基腺苷 (m ⁶ A) 修饰是最常见的转录后 mRNA 修饰，调节 mRNA 衰减和剪接。它在正常发育、分化和疾病进展过程中发挥着重要作用。这种修改是由一组写入器、擦除器和读取器蛋白质调节的。 YTH 结构域蛋白家族由三个同源 m ⁶ A 结合蛋白 Ythdf1、Ythdf2 和 Ythdf3 组成，这三种蛋白被认为具有不同的细胞功能。然而，它们的序列相似性和结合相同靶标的倾向表明它们可能具有重叠的作用。我们系统地击倒了（KO）Mettl3 作者、每个 Ythdf 读者以及三个读者（三重 KO）。然后，我们评估了体内对小鼠配子发生、出生后活力的影响，以及体外对小鼠胚胎干细胞（mESC）的影响。在配子发生过程中， Mettl3-KO 的严重性随着缺失发生在该过程的早期而增加，并且 Ythdf2 具有无法被 Ythdf1 或 Ythdf3 补偿的主导作用，因为不同细胞类型的 reader 表达模式在数量和数量上存在差异。在空间位置上。将三个读者一起剔除并系统地测试可行的后代基因型揭示了早期发育过程中读者角色的冗余，即Ythdf1/2/3基因剂量依赖性。最后，在 mESC 中，三个 Ythdf 阅读器蛋白之间存在补偿，因为分化阻力和对 mRNA 衰减的显着影响仅发生在三重 KO 细胞中，而不是在单 KO 细胞中。 因此，我们提出了 Ythdf reader 功能的新模型，其中当所有三个 reader 在相同细胞类型中等效共表达时，存在深刻的剂量依赖性冗余。