Institute for Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
Nucleic Acids Res. 2024 Sep 23;52(17):10668-10682. doi: 10.1093/nar/gkae622.
RNA helicases are involved in RNA metabolism in an ATP-dependent manner. Although many RNA helicases unwind the RNA structure and/or remove proteins from the RNA, some can load their interacting proteins onto RNAs. Here, we developed an in vitro strategy to identify the ATP-dependent factors involved in spliceosomal uridine-rich small nuclear RNA (U snRNA) export. We identified the RNA helicase UAP56/DDX39B, a component of the mRNA export complex named the transcription-export (TREX) complex, and its closely related RNA helicase URH49/DDX39A as the factors that stimulated RNA binding of PHAX, an adapter protein for U snRNA export. ALYREF, another TREX component, acted as a bridge between PHAX and UAP56/DDX39B. We also showed that UAP56/DDX39B and ALYREF participate in U snRNA export through a mechanism distinct from that of mRNA export. This study describes a novel aspect of the TREX components for U snRNP biogenesis and highlights the loading activity of RNA helicases.
RNA 解旋酶以 ATP 依赖的方式参与 RNA 代谢。尽管许多 RNA 解旋酶能使 RNA 结构解旋和/或从 RNA 上移除蛋白质，但有些 RNA 解旋酶可以将其相互作用的蛋白质加载到 RNA 上。在这里，我们开发了一种体外策略来鉴定剪接体尿嘧啶丰富的小核 RNA（U snRNA）输出中涉及的 ATP 依赖性因子。我们鉴定了 RNA 解旋酶 UAP56/DDX39B，它是称为转录-输出（TREX）复合物的 mRNA 输出复合物的一个组成部分，以及与其密切相关的 RNA 解旋酶 URH49/DDX39A，它们是刺激 PHAX（一种 U snRNA 输出的衔接蛋白）与 RNA 结合的因子。另一个 TREX 成分 A LYREF 充当了 PHAX 和 UAP56/DDX39B 之间的桥梁。我们还表明，UAP56/DDX39B 和 A LYREF 通过一种与 mRNA 输出不同的机制参与 U snRNA 输出。本研究描述了 TREX 成分在 U snRNP 生物发生中的一个新方面，并强调了 RNA 解旋酶的加载活性。
