Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.
Center for Integrated Protein Science Munich at Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Garching, Germany.
Nat Struct Mol Biol. 2017 Feb;24(2):152-161. doi: 10.1038/nsmb.3351. Epub 2017 Jan 16.
mRNA localization is an essential mechanism of gene regulation and is required for processes such as stem-cell division, embryogenesis and neuronal plasticity. It is not known which features in the cis-acting mRNA localization elements (LEs) are specifically recognized by motor-containing transport complexes. To the best of our knowledge, no high-resolution structure is available for any LE in complex with its cognate protein complex. Using X-ray crystallography and complementary techniques, we carried out a detailed assessment of an LE of the ASH1 mRNA from yeast, its complex with its shuttling RNA-binding protein She2p, and its highly specific, cytoplasmic complex with She3p. Although the RNA alone formed a flexible stem loop, She2p binding induced marked conformational changes. However, only joining by the unstructured She3p resulted in specific RNA recognition. The notable RNA rearrangements and joint action of a globular and an unfolded RNA-binding protein offer unprecedented insights into the step-wise maturation of an mRNA-transport complex.
mRNA 定位是基因调控的一种基本机制，对于干细胞分裂、胚胎发生和神经元可塑性等过程是必需的。目前尚不清楚顺式作用的 mRNA 定位元件 (LE) 中的哪些特征被含有马达的运输复合物特异性识别。据我们所知，与同源蛋白复合物结合的任何 LE 都没有高分辨率结构。我们使用 X 射线晶体学和互补技术，对来自酵母的 ASH1 mRNA 的 LE、与其穿梭 RNA 结合蛋白 She2p 的复合物以及与其高度特异性的细胞质复合物 She3p 进行了详细评估。尽管单独的 RNA 形成了一个灵活的茎环结构，但 She2p 结合诱导了明显的构象变化。然而，只有无结构的 She3p 的加入才能导致特定的 RNA 识别。球形和未折叠 RNA 结合蛋白的显著 RNA 重排和联合作用为逐步成熟的 mRNA 运输复合物提供了前所未有的见解。
