CNRS-LGDP UMR 5096, 58 avenue Paul Alduy, 66860 Perpignan, France.
Université de Perpignan Via Domitia-LGDP UMR5096, 58 avenue Paul Alduy, 66860 Perpignan, France.
Nucleic Acids Res. 2024 Jul 22;52(13):7910-7924. doi: 10.1093/nar/gkae363.
Until recently, the general 5'-3' mRNA decay was placed in the cytosol after the mRNA was released from ribosomes. However, the discovery of an additional 5' to 3' pathway, the Co-Translational mRNA Decay (CTRD), changed this paradigm. Up to date, defining the real contribution of CTRD in the general mRNA turnover has been hardly possible as the enzyme involved in this pathway is also involved in cytosolic decay. Here we overcame this obstacle and created an Arabidopsis line specifically impaired for CTRD called XRN4ΔCTRD. Through a genome-wide analysis of mRNA decay rate in shoot and root, we tested the importance of CTRD in mRNA turnover. First, we observed that mRNAs tend to be more stable in root than in shoot. Next, using XRN4ΔCTRD line, we demonstrated that CTRD is a major determinant in mRNA turnover. In shoot, the absence of CTRD leads to the stabilization of thousands of transcripts while in root its absence is highly compensated resulting in faster decay rates. We demonstrated that this faster decay rate is partially due to the XRN4-dependent cytosolic decay. Finally, we correlated this organ-specific effect with XRN4ΔCTRD line phenotypes revealing a crucial role of CTRD in mRNA homeostasis and proper organ development.
直到最近，一般的 5'-3' mRNA 降解才在 mRNA 从核糖体释放后发生在细胞质中。然而，另一种 5' 到 3' 途径，共翻译 mRNA 降解（CTRD）的发现改变了这一模式。迄今为止，由于参与该途径的酶也参与细胞质降解，因此很难确定 CTRD 在一般 mRNA 周转中的实际贡献。在这里，我们克服了这一障碍，创建了一种专门用于 CTRD 的拟南芥品系，称为 XRN4ΔCTRD。通过对地上部和根部 mRNA 降解率的全基因组分析，我们测试了 CTRD 在 mRNA 周转中的重要性。首先，我们观察到 mRNA 在根部比在地上部更稳定。接下来，使用 XRN4ΔCTRD 系，我们证明了 CTRD 是 mRNA 周转的主要决定因素。在地上部，缺乏 CTRD 会导致数千个转录本的稳定，而在根部，缺乏 CTRD 则得到高度补偿，导致降解率加快。我们证明这种更快的降解率部分是由于 XRN4 依赖的细胞质降解。最后，我们将这种器官特异性效应与 XRN4ΔCTRD 系表型相关联，揭示了 CTRD 在 mRNA 动态平衡和适当器官发育中的关键作用。
