Argonaute protein identity and pairing geometry determine cooperativity in mammalian RNA silencing
Student AuthorsJennifer A. Broderick
UMass Chan AffiliationsDepartment of Biochemistry and Molecular Pharmacology
Document TypeJournal Article
KeywordsAnimals; Base Sequence; Cells, Cultured; Eukaryotic Initiation Factors; Humans; Mice; Protein Binding; *RNA Interference; RNA, Small Interfering
Biochemistry, Biophysics, and Structural Biology
Medicine and Health Sciences
Neuroscience and Neurobiology
MetadataShow full item record
AbstractSmall 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.
SourceRNA. 2011 Oct;17(10):1858-69. Epub 2011 Aug 30. Link to article on publisher's site
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/33232
Related ResourcesLink to Article in PubMed
RightsCopyright © 2011 RNA Society. Freely available online through the RNA Open Access option.