title: ATP requirements and small interfering RNA structure in the RNA interference pathway.
abstract: We examined the role of ATP in the RNA interference (RNAi) pathway. Our data reveal two ATP-dependent steps and suggest that the RNAi reaction comprises at least four sequential steps: ATP-dependent processing of double-stranded RNA into small interfering RNAs (siRNAs), incorporation of siRNAs into an inactive approximately 360 kDa protein/RNA complex, ATP-dependent unwinding of the siRNA duplex to generate an active complex, and ATP-independent recognition and cleavage of the RNA target. Furthermore, ATP is used to maintain 5' phosphates on siRNAs. A 5' phosphate on the target-complementary strand of the siRNA duplex is required for siRNA function, suggesting that cells check the authenticity of siRNAs and license only bona fide siRNAs to direct target RNA destruction.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nykänen
authors.forename: B
authors.initials: B
authors.lastname: Haley
authors.forename: P D
authors.initials: PD
authors.lastname: Zamore
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D004330:Drosophila / Q000196:embryology; D020868:Gene Silencing; D008957:Models, Genetic; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012330:RNA, Double-Stranded / Q000378:metabolism*; D034741:RNA, Small Interfering; D022661:RNA, Untranslated / Q000378:metabolism*
chemical_list: D011506:Proteins; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D000255:Adenosine Triphosphate