Structure of pre-miR-31 reveals an active role in Dicer-TRBP complex processing.
Structure of pre-miR-31 reveals an active role in Dicer-TRBP complex processing.
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DOI：
10.1073/pnas.2300527120
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发表时间：
2023-09-26
影响因子：
11.1
通讯作者：
Keane, Sarah C.
中科院分区：
文献类型：
--
作者：
Ma, Sicong;Kotar, Anita;Hall, Ian;Grote, Scott;Rouskin, Silvi;Keane, Sarah C.
成熟的microRNA与Argonaute蛋白复合，起着控制细胞中蛋白质水平的作用。成熟的microRNA通过一系列酶促加工事件从较长的初级和前体转录物产生。虽然蛋白质通常是microRNA生物合成途径中各个步骤的调节剂，但尚未鉴定出与pre-miR-31相互作用的蛋白质。因此，控制miR-31水平的机制迄今为止仍然难以捉摸。本研究揭示了pre-miR-31的三维结构，并揭示了Dicer-TRBP复合物的加工由pre-miR-31结构内部调节的机制。对microRNA生物发生的结构和分子决定因素的深入了解对RNA靶向药物开发和基因沉默短发夹RNA的设计具有重要意义。作为基因表达的重要转录后调节因子，microRNA（miRNA）的水平必须严格维持。许多miRNA的生物发生是由反式作用蛋白伴侣通过多种机制介导的，包括RNA结构的重塑。miR-31在许多癌症中作为致癌基因发挥作用，有趣的是，其生物发生并不受蛋白质结合伴侣的调节。因此，miR-31的前体元件（pre-miR-31）的内在结构特性可以提供调节其生物发生的机制。我们确定了前体miR-31的溶液结构，以研究不同结构元件在调节Dicer-TRBP复合物加工中的作用。我们发现螺旋茎内错配的存在或不存在并不强烈影响pre-miRNA的Dicer-TRBP加工。然而，在切割位点的顶端环的大小和结构都是通过Dicer-TRBP复合物进行区分的关键要素。有趣的是，我们的NMR衍生结构揭示了连接Dicer切割位点和顶端环的三重碱基对的存在。该区域的突变分析表明，接合区的稳定性强烈影响Dicer-TRBP复合物的加工。我们的研究结果丰富了我们对RNA结构在调节miRNA生物合成中所起的积极作用的理解，这对基因表达的控制有直接的影响。
Mature microRNAs, in complex with Argonaute proteins, function to control protein levels in the cell. Mature microRNAs are produced via a series of enzymatic processing events from longer primary and precursor transcripts. While proteins are commonly regulators of various steps in the microRNA biogenesis pathway, no proteins that interact with pre-miR-31 have been identified. Therefore, the mechanism by which miR-31 levels are controlled has until now remained elusive. The present study reveals the three-dimensional structure of pre-miR-31 and uncovers a mechanism by which processing by the Dicer–TRBP complex is regulated internally by the pre-miR-31 structure. Insights into the structure and molecular determinants of microRNA biogenesis have implications in RNA-targeted drug development and design of short hairpin RNAs for gene silencing. As an essential posttranscriptional regulator of gene expression, microRNA (miRNA) levels must be strictly maintained. The biogenesis of many miRNAs is mediated by trans-acting protein partners through a variety of mechanisms, including remodeling of the RNA structure. miR-31 functions as an oncogene in numerous cancers, and interestingly, its biogenesis is not known to be regulated by protein-binding partners. Therefore, the intrinsic structural properties of the precursor element of miR-31 (pre-miR-31) can provide a mechanism by which its biogenesis is regulated. We determined the solution structure of pre-miR-31 to investigate the role of distinct structural elements in regulating processing by the Dicer–TRBP complex. We found that the presence or absence of mismatches within the helical stem does not strongly influence Dicer–TRBP processing of the pre-miRNAs. However, both the apical loop size and structure at the Dicing site are key elements for discrimination by the Dicer–TRBP complex. Interestingly, our NMR-derived structure reveals the presence of a triplet of base pairs that link the Dicer cleavage site and the apical loop. Mutational analysis in this region suggests that the stability of the junction region strongly influences processing by the Dicer–TRBP complex. Our results enrich our understanding of the active role that RNA structure plays in regulating miRNA biogenesis, which has direct implications for the control of gene expression.
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TRBP确保在RNA拥挤的环境中对前体microRNA的有效培训。
影响因子：
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作者：
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