A compact regulatory RNA element in mouse Hsp70 mRNA.
A compact regulatory RNA element in mouse Hsp70 mRNA.
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小鼠 Hsp70 mRNA 中的紧凑调节 RNA 元件。
DOI：
10.1093/narmme/ugae002
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发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Pyle,AnnaMarie
中科院分区：
文献类型：
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作者：
Wang,Wenshuai;Liu,Fei;Ugalde,MariaVera;Pyle,AnnaMarie
热休克蛋白70（70 kDa热休克蛋白）通过协助新合成和错误折叠的蛋白质折叠来执行分子伴侣功能，从而抵消各种细胞应激并预防多种疾病，包括神经退行性疾病和癌症。热休克后，热休克蛋白70基因的表达是由典型的帽依赖性翻译机制介导的。然而，热休克过程中Hsp 70表达的分子机制仍然是难以捉摸的。有趣的是，Hsp 70信使RNA（mRNA）的5′端似乎形成了一个紧凑的结构，具有以帽非依赖性方式调节蛋白质表达的潜力。在这里，我们确定了mHsp 70 5′-末端mRNA序列的最小长度，该序列是RNA折叠成高度紧凑结构所需的。该RNA元件的这一跨度被映射，并且通过化学探测表征二级结构，从而产生包括多个稳定茎的二级结构模型，包括含有典型起始密码子的茎。所有这些成分，包括5′开放阅读框（ORF）的一小段，都被证明对RNA折叠至关重要。本工作为进一步研究热休克过程中Hsp 70 5′端非翻译区和ORF序列中的翻译调控结构的作用提供了结构基础。
Hsp70 (70 kDa heat shock protein) performs molecular chaperone functions by assisting the folding of newly synthesized and misfolded proteins, thereby counteracting various cell stresses and preventing multiple diseases, including neurodegenerative disorders and cancers. It is well established that, immediately after heat shock, Hsp70 gene expression is mediated by a canonical mechanism of cap-dependent translation. However, the molecular mechanism of Hsp70 expression during heat shock remains elusive. Intriguingly, the 5′ end of Hsp70 messenger RNA (mRNA) appears to form a compact structure with the potential to regulate protein expression in a cap-independent manner. Here, we determined the minimal length of the mHsp70 5′-terminal mRNA sequence that is required for RNA folding into a highly compact structure. This span of this RNA element was mapped and the secondary structure characterized by chemical probing, resulting in a secondary structural model that includes multiple stable stems, including one containing the canonical start codon. All of these components, including a short stretch of the 5′ open reading frame (ORF), were shown to be vital for RNA folding. This work provides a structural basis for future investigations on the role of translational regulatory structures in the 5′ untranslated region and ORF sequences of Hsp70 during heat shock.