Department of Biochemistry, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5C1, Canada.
Department of Pathology, The University of Western Ontario, 1151 Richmond Street, London, ON N6A 5C1, Canada.
Nucleic Acids Res. 2019 Apr 8;47(6):3045-3057. doi: 10.1093/nar/gkz043.
Uridylation-dependent RNA decay is a widespread eukaryotic pathway modulating RNA homeostasis. Terminal uridylyltransferases (Tutases) add untemplated uridyl residues to RNA 3'-ends, marking them for degradation by the U-specific exonuclease Dis3L2. In Schizosaccharomyces pombe, Cid1 uridylates a variety of RNAs. In this study, we investigate the prevalence and impact of uridylation-dependent RNA decay in S. pombe by transcriptionally profiling cid1 and dis3L2 deletion strains. We found that the exonuclease Dis3L2 represents a bottleneck in uridylation-dependent mRNA decay, whereas Cid1 plays a redundant role that can be complemented by other Tutases. Deletion of dis3L2 elicits a cellular stress response, upregulating transcription of genes involved in protein folding and degradation. Misfolded proteins accumulate in both deletion strains, yet only trigger a strong stress response in dis3L2 deficient cells. While a deletion of cid1 increases sensitivity to protein misfolding stress, a dis3L2 deletion showed no increased sensitivity or was even protective. We furthermore show that uridylyl- and adenylyltransferases cooperate to generate a 5'-NxAUUAAAA-3' RNA motif on dak2 mRNA. Our studies elucidate the role of uridylation-dependent RNA decay as part of a global mRNA surveillance, and we found that perturbation of this pathway leads to the accumulation of misfolded proteins and elicits cellular stress responses.
尿苷酰化依赖的 RNA 降解是一种广泛存在的真核途径，可调节 RNA 动态平衡。末端尿苷酰转移酶（Tutases）在 RNA 3' 末端添加非模板尿苷残基，将其标记为 U 特异性外切酶 Dis3L2 降解。在酿酒酵母中，Cid1 尿苷酰化多种 RNA。在这项研究中，我们通过转录谱分析 cid1 和 dis3L2 缺失菌株，研究了尿苷酰化依赖的 RNA 降解在 S. 酿酒酵母中的普遍性和影响。我们发现，外切酶 Dis3L2 是尿苷酰化依赖的 mRNA 降解的瓶颈，而 Cid1 则发挥冗余作用，可被其他 Tutases 补充。Dis3L2 的缺失会引发细胞应激反应，上调参与蛋白质折叠和降解的基因转录。两种缺失菌株中都会积累错误折叠的蛋白质，但只有在 dis3L2 缺失细胞中才会引发强烈的应激反应。虽然 cid1 的缺失增加了对蛋白质错误折叠应激的敏感性，但 dis3L2 的缺失没有增加敏感性，甚至具有保护作用。我们还表明，尿苷酰转移酶和腺苷酰转移酶合作在 dak2 mRNA 上产生 5'-NxAUUAAAA-3' RNA 基序。我们的研究阐明了尿苷酰化依赖的 RNA 降解作为全局 mRNA 监测的一部分的作用，并且我们发现该途径的干扰会导致错误折叠蛋白质的积累，并引发细胞应激反应。
