Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Department of Pharmacology, Weill Medical College, Cornell University, New York, NY 10065, USA.
J Cell Sci. 2018 Mar 1;131(5):jcs201996. doi: 10.1242/jcs.201996.
Following fertilization, embryos develop for a substantial amount of time with a transcriptionally silent genome. Thus, early development is maternally programmed, as it solely relies on RNAs and proteins that are provided by the female gamete. However, these maternal instructions are not sufficient to support later steps of embryogenesis and are therefore gradually replaced by novel products synthesized from the zygotic genome. This switch in the origin of molecular players that drive early development is known as the maternal-to-zygotic transition (MZT). MZT is a universal phenomenon among all metazoans and comprises two interconnected processes: maternal mRNA degradation and the transcriptional awakening of the zygotic genome. The recent adaptation of high-throughput methods for use in embryos has deepened our knowledge of the molecular principles underlying MZT. These mechanisms comprise conserved strategies for RNA regulation that operate in many well-studied cellular contexts but that have adapted differently to early development. In this Review, we will discuss advances in our understanding of post-transcriptional regulatory pathways that drive maternal mRNA clearance during MZT, with an emphasis on recent data in zebrafish embryos on codon-mediated mRNA decay, the contributions of microRNAs (miRNAs) and RNA-binding proteins to this process, and the roles of RNA modifications in the stability control of maternal mRNAs.
受精后，胚胎在转录沉默的基因组中发育很长一段时间。因此，早期发育是由母体编程的，因为它仅依赖于由雌性配子提供的 RNA 和蛋白质。然而，这些母体指令不足以支持胚胎发生的后期步骤，因此逐渐被来自合子基因组合成的新产物所取代。这种驱动早期发育的分子参与者来源的转变称为母源到合子的过渡（MZT）。MZT 是所有后生动物中的普遍现象，包括两个相互关联的过程：母体 mRNA 的降解和合子基因组的转录激活。最近，高通量方法在胚胎中的应用加深了我们对 MZT 下分子原理的理解。这些机制包括在许多研究充分的细胞环境中起作用的保守的 RNA 调控策略，但它们对早期发育的适应方式不同。在这篇综述中，我们将讨论在理解驱动 MZT 期间母体 mRNA 清除的转录后调控途径方面的进展，重点介绍斑马鱼胚胎中关于密码子介导的 mRNA 降解、miRNA 和 RNA 结合蛋白对该过程的贡献，以及 RNA 修饰在母体 mRNA 稳定性控制中的作用的最新数据。
