Cell-cell contact globally activates microRNA biogenesis
Cell-cell contact globally activates microRNA biogenesis
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DOI：
10.1073/pnas.0811523106
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发表时间：
2009-04-28
影响因子：
11.1
通讯作者：
Mendell, Joshua T.
中科院分区：
文献类型：
--
作者：
Hwang, Hun-Way;Wentzel, Erik A.;Mendell, Joshua T.
微小RNA（miRNAs）是18 - 24个核苷酸的RNA分子，可调节信使RNA（mRNAs）。转录后机制在发育过程以及癌细胞中调节miRNA的丰度，在癌细胞中miRNAs经常表现出表达失调。在这些情况下，控制miRNA生物发生总体效率的分子机制仍未完全了解，而且目前缺乏对这些途径进行生化剖析的实验系统。在此，我们证明在广泛使用的细胞培养系统中，miRNAs受到动态的转录后调控。随着多种哺乳动物和果蝇细胞系生长至更高密度，miRNA生物发生被整体激活，导致成熟miRNA水平升高以及对靶标构建体的更强抑制。miRNA丰度的这种广泛增加与Drosha对miRNAs的加工增强以及RNA诱导沉默复合物更高效的形成有关。这些发现揭示了在细胞培养环境中准确分析miRNAs所必需的一个关键参数，建立了一个易于处理的系统用于研究受调控的miRNA生物发生，并且可能为了解在生理和病理生理状态下影响miRNA表达的机制提供见解。
MicroRNAs (miRNAs) are 18- to 24-nt RNA molecules that regulate messenger RNAs (mRNAs). Posttranscriptional mechanisms regulate miRNA abundance during development as well as in cancer cells where miRNAs frequently exhibit dysregulated expression. The molecular mechanisms that govern the global efficiency of miRNA biogenesis in these settings remain incompletely understood, and experimental systems for the biochemical dissection of these pathways are currently lacking. Here, we demonstrate that miRNAs are subject to dynamic posttranscriptional regulation in widely used cell culture systems. As diverse mammalian and Drosophila cell lines are grown to increasing density, miRNA biogenesis is globally activated, leading to elevated mature miRNA levels and stronger repression of target constructs. This broad increase in miRNA abundance is associated with enhanced processing of miRNAs by Drosha and more efficient formation of RNA-induced silencing complexes. These findings uncover a critical parameter necessary for accurate analysis of miRNAs in cell culture settings, establish a tractable system for the study of regulated miRNA biogenesis, and may provide insight into mechanisms that influence miRNA expression in physiologic and pathophysiologic states.