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Structural analysis of 5'-mRNA-cap interactions with the human AGO2 MID domain.

ABSTRACT: In RNA silencing, microRNA (miRNA)-mediated translational repression occurs through mechanisms that do not invoke messenger-RNA (mRNA) target cleavage by Argonaute proteins. The nature of these mechanisms is unclear, but several recent studies have proposed that a direct interaction between the mRNA-cap and the middle (MID) domain of Argonautes is involved. Here, we present crystallographic and NMR data demonstrating that cap analogues do not bind significantly to the isolated MID domain of human Argonaute 2 (hAGO2) and are found in the miRNA 5'-nucleotide binding site in an implausible binding mode. Additionally, in vitro pull-down experiments with full-length hAGO2 indicate that the interaction with cap analogues is nonspecific.

SUBMITTER: Frank F

PROVIDER: S-EPMC3090017 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Structural analysis of 5'-mRNA-cap interactions with the human AGO2 MID domain.

Frank Filipp F Fabian Marc R MR Stepinski Janusz J Jemielity Jacek J Darzynkiewicz Edward E Sonenberg Nahum N Nagar Bhushan B

EMBO reports 20110408 5

In RNA silencing, microRNA (miRNA)-mediated translational repression occurs through mechanisms that do not invoke messenger-RNA (mRNA) target cleavage by Argonaute proteins. The nature of these mechanisms is unclear, but several recent studies have proposed that a direct interaction between the mRNA-cap and the middle (MID) domain of Argonautes is involved. Here, we present crystallographic and NMR data demonstrating that cap analogues do not bind significantly to the isolated MID domain of huma ...[more]

PMID: 21475248

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The human Ago2 MC region does not contain an eIF4E-like mRNA cap binding motif.

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