Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
Biochem Biophys Res Commun. 2021 May 14;553:9-16. doi: 10.1016/j.bbrc.2021.03.066. Epub 2021 Mar 20.
The RNA-binding protein Ataxin-2 regulates translation and mRNA stability through cytoplasmic polyadenylation of the targets. Here we newly identified DDX6 as a positive regulator of the cytoplasmic polyadenylation. Analysis of Ataxin-2 interactome using LC-MS/MS revealed prominent interaction with the DEAD-box RNA helicase DDX6. DDX6 interacted with components of the Ataxin-2 polyadenylation machinery; Ataxin-2, PABPC1 and PAPD4. As in the case for Ataxin-2 downregulation, DDX6 downregulation led to an increase in Ataxin-2 target mRNAs with short poly(A) tails as well as a reduction in their protein expression. In contrast, Ataxin-2 target mRNAs with short poly(A) tails were decreased by the overexpression of Ataxin-2, which was compromised by the DDX6 downregulation. However, polyadenylation induced by Ataxin-2 tethering was not affected by the DDX6 downregulation. Taken together, these results suggest that DDX6 positively regulates Ataxin-2-induced cytoplasmic polyadenylation to maintain poly(A) tail length of the Ataxin-2 targets provably through accelerating binding of Ataxin-2 to the target mRNAs.
RNA 结合蛋白 Ataxin-2 通过目标物的细胞质多聚腺苷酸化来调节翻译和 mRNA 稳定性。在这里，我们新发现了 DDX6 是细胞质多聚腺苷酸化的正向调节剂。使用 LC-MS/MS 对 Ataxin-2 相互作用组进行分析，揭示了与 DEAD 盒 RNA 解旋酶 DDX6 的显著相互作用。DDX6 与 Ataxin-2 多聚腺苷酸化机制的组件相互作用；Ataxin-2、PABPC1 和 PAPD4。与 Ataxin-2 下调的情况一样，DDX6 下调导致具有短多聚（A）尾巴的 Ataxin-2 靶 mRNA 增加，以及它们的蛋白质表达减少。相比之下，Ataxin-2 靶 mRNA 具有短多聚（A）尾巴是由 Ataxin-2 的过表达减少的，这是由 DDX6 下调引起的。然而，Ataxin-2 系留诱导的多聚腺苷酸化不受 DDX6 下调的影响。总之，这些结果表明 DDX6 正向调节 Ataxin-2 诱导的细胞质多聚腺苷酸化，以维持 Ataxin-2 靶标的多聚（A）尾长，可通过加速 Ataxin-2 与靶 mRNA 的结合来证明。
