HuR protein attenuates miRNA-mediated repression by promoting miRISC dissociation from the target RNA

Kundu, Pradipta ; Fabian, Marc R. ; Sonenberg, Nahum ; Bhattacharyya, Suvendra N. ; Filipowicz, Witold (2012) HuR protein attenuates miRNA-mediated repression by promoting miRISC dissociation from the target RNA Nucleic Acids Research, 40 (11). pp. 5088-5100. ISSN 0305-1048

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Official URL: https://academic.oup.com/nar/article/40/11/5088/24...

Related URL: http://dx.doi.org/10.1093/nar/gks148

Abstract

The microRNA (miRNA)-mediated repression of protein synthesis in mammalian cells is a reversible process. Target mRNAs with regulatory AU-rich Elements (AREs) in their 3′-Untranslated Regions (3′-UTR) can be relieved of miRNA repression under cellular stress in a process involving the embryonic lethal and altered vision family ARE-binding protein HuR. The HuR-mediated derepression occurred even when AREs were positioned at a considerable distance from the miRNA sites raising questions about the mechanism of HuR action. Here, we show that the relief of miRNA-mediated repression involving HuR can be recapitulated in different in vitro systems in the absence of stress, indicating that HuR alone is sufficient to relieve the miRNA repression upon binding to RNA ARE. Using in vitro assays with purified miRISC and recombinant HuR and its mutants, we show that HuR, likely by its property to oligomerize along RNA, leads to the dissociation of miRISC from target RNA even when miRISC and HuR binding sites are positioned at a distance. Further, we demonstrate that HuR association with AREs can also inhibit miRNA-mediated deadenylation of mRNA in the Krebs-2 ascites extract, in a manner likewise depending on the potential of HuR to oligomerize.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
ID Code:108150
Deposited On:01 Feb 2018 11:12
Last Modified:01 Feb 2018 11:12

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