Argonaute protein identity and pairing geometry determine cooperativity in mammalian RNA silencing
Student Authors
Jennifer A. BroderickUMass Chan Affiliations
Department of Biochemistry and Molecular PharmacologyDocument Type
Journal ArticlePublication Date
2011-10-01Keywords
Animals; Base Sequence; Cells, Cultured; Eukaryotic Initiation Factors; Humans; Mice; Protein Binding; *RNA Interference; RNA, Small InterferingBiochemistry, Biophysics, and Structural Biology
Life Sciences
Medicine and Health Sciences
Neuroscience and Neurobiology
Metadata
Show full item recordAbstract
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.Source
RNA. 2011 Oct;17(10):1858-69. Epub 2011 Aug 30. Link to article on publisher's siteDOI
10.1261/rna.2778911Permanent Link to this Item
http://hdl.handle.net/20.500.14038/33232PubMed ID
21878547Related Resources
Link to Article in PubMedRights
Copyright © 2011 RNA Society. Freely available online through the RNA Open Access option.ae974a485f413a2113503eed53cd6c53
10.1261/rna.2778911