Lorenzo-Orts Laura, Pauli Andrea
Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria.
Biochem Soc Trans. 2024 Apr 24;52(2):861-871. doi: 10.1042/BST20231122.
A large number of mRNAs of maternal origin are produced during oogenesis and deposited in the oocyte. Since transcription stops at the onset of meiosis during oogenesis and does not resume until later in embryogenesis, maternal mRNAs are the only templates for protein synthesis during this period. To ensure that a protein is made in the right place at the right time, the translation of maternal mRNAs must be activated at a specific stage of development. Here we summarize our current understanding of the sophisticated mechanisms that contribute to the temporal repression of maternal mRNAs, termed maternal mRNA dormancy. We discuss mechanisms at the level of the RNA itself, such as the regulation of polyadenine tail length and RNA modifications, as well as at the level of RNA-binding proteins, which often block the assembly of translation initiation complexes at the 5' end of an mRNA or recruit mRNAs to specific subcellular compartments. We also review microRNAs and other mechanisms that contribute to repressing translation, such as ribosome dormancy. Importantly, the mechanisms responsible for mRNA dormancy during the oocyte-to-embryo transition are also relevant to cellular quiescence in other biological contexts.
在卵子发生过程中会产生大量源自母体的mRNA，并沉积在卵母细胞中。由于卵子发生过程中减数分裂开始时转录就会停止，直到胚胎发生后期才会恢复，因此在此期间母体mRNA是蛋白质合成的唯一模板。为确保蛋白质在正确的时间和位置合成，母体mRNA的翻译必须在特定的发育阶段被激活。在此，我们总结了目前对导致母体mRNA暂时抑制（即母体mRNA休眠）的复杂机制的理解。我们讨论了RNA本身水平的机制，如多聚腺苷酸尾巴长度的调节和RNA修饰，以及RNA结合蛋白水平的机制，RNA结合蛋白通常会在mRNA的5'端阻止翻译起始复合物的组装，或将mRNA招募到特定的亚细胞区室。我们还回顾了微小RNA和其他有助于抑制翻译的机制，如核糖体休眠。重要的是，卵母细胞向胚胎转变过程中负责mRNA休眠的机制在其他生物学背景下也与细胞静止相关。
