GSBS Student Publications

Student Author(s)

Jennifer A. Broderick

GSBS Program


UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology



Document Type


Medical Subject Headings

Animals; Base Sequence; Cells, Cultured; Eukaryotic Initiation Factors; Humans; Mice; Protein Binding; *RNA Interference; RNA, Small Interfering


Biochemistry, Biophysics, and Structural Biology | Life Sciences | Medicine and Health Sciences | Neuroscience and Neurobiology


Small RNAs loaded into Argonaute proteins direct silencing of complementary target mRNAs. It has been proposed that multiple, imperfectly complementary small interfering RNAs or microRNAs, when bound to the 3' untranslated region of a target mRNA, function cooperatively to silence target expression. We report that, in cultured human HeLa cells and mouse embryonic fibroblasts, Argonaute1 (Ago1), Ago3, and Ago4 act cooperatively to silence both perfectly and partially complementary target RNAs bearing multiple small RNA-binding sites. Our data suggest that for Ago1, Ago3, and Ago4, multiple, adjacent small RNA-binding sites facilitate cooperative interactions that stabilize Argonaute binding. In contrast, small RNAs bound to Ago2 and pairing perfectly to an mRNA target act independently to silence expression. Noncooperative silencing by Ago2 does not require the endoribonuclease activity of the protein: A mutant Ago2 that cannot cleave its mRNA target also silences noncooperatively. We propose that Ago2 binds its targets by a mechanism fundamentally distinct from that used by the three other mammalian Argonaute proteins.

Rights and Permissions

Citation: RNA. 2011 Oct;17(10):1858-69. Epub 2011 Aug 30. Link to article on publisher's site


Copyright © 2011 RNA Society. Freely available online through the RNA Open Access option.

Related Resources

Link to Article in PubMed


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