Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France.
Plant Cell. 2022 Mar 4;34(3):967-988. doi: 10.1093/plcell/koab310.
RNA exosome complexes provide the main 3'-5'-exoribonuclease activities in eukaryotic cells and contribute to the maturation and degradation of virtually all types of RNA. RNA exosomes consist of a conserved core complex that associates with exoribonucleases and with multimeric cofactors that recruit the enzyme to its RNA targets. Despite an overall high level of structural and functional conservation, the enzymatic activities and compositions of exosome complexes and their cofactor modules differ among eukaryotes. This review highlights unique features of plant exosome complexes, such as the phosphorolytic activity of the core complex, and discusses the exosome cofactors that operate in plants and are dedicated to the maturation of ribosomal RNA, the elimination of spurious, misprocessed, and superfluous transcripts, or the removal of mRNAs cleaved by the RNA-induced silencing complex and other mRNAs prone to undergo silencing.
RNA 外切体复合物在真核细胞中提供主要的 3′-5′-外核糖核酸酶活性，并有助于实质上所有类型 RNA 的成熟和降解。RNA 外切体由一个保守的核心复合物组成，该复合物与外核糖核酸酶以及多聚体辅助因子结合，将酶募集到其 RNA 靶标上。尽管在整体上具有高度的结构和功能保守性，但外切体复合物及其辅助因子模块的酶活性和组成在真核生物中有所不同。本文综述了植物外切体复合物的独特特征，例如核心复合物的磷酸解活性，并讨论了在植物中发挥作用的外切体辅助因子，这些辅助因子专门用于核糖体 RNA 的成熟、清除虚假的、错误加工的和多余的转录本，或去除被 RNA 诱导沉默复合物和其他易发生沉默的 mRNA 切割的 mRNA。
