Phosphate and R2D2 Restrict the Substrate Specificity of Dicer-2, an ATP-Driven Ribonuclease
AuthorsCenik, Elif Sarinay
Hall, Traci M. Tanaka
Zamore, Phillip D.
UMass Chan AffiliationsDepartment of Biochemistry and Molecular Pharmacology
Document TypeJournal Article
RNA, Small Interfering
Biochemistry, Biophysics, and Structural Biology
Pharmacology, Toxicology and Environmental Health
MetadataShow full item record
AbstractDrosophila Dicer-2 generates small interfering RNAs (siRNAs) from long double-stranded RNA (dsRNA), whereas Dicer-1 produces microRNAs (miRNAs) from pre-miRNA. What makes the two Dicers specific for their biological substrates? We find that purified Dicer-2 can efficiently cleave pre-miRNA, but that inorganic phosphate and the Dicer-2 partner protein R2D2 inhibit pre-miRNA cleavage. Dicer-2 contains C-terminal RNase III domains that mediate RNA cleavage and an N-terminal helicase motif, whose function is unclear. We show that Dicer-2 is a dsRNA-stimulated ATPase that hydrolyzes ATP to ADP; ATP hydrolysis is required for Dicer-2 to process long dsRNA, but not pre-miRNA. Wild-type Dicer-2, but not a mutant defective in ATP hydrolysis, can generate siRNAs faster than it can dissociate from a long dsRNA substrate. We propose that the Dicer-2 helicase domain uses ATP to generate many siRNAs from a single molecule of dsRNA before dissociating from its substrate.
SourceCenik et al., Phosphate and R2D2 Restrict the Substrate Specificity of Dicer-2, an ATP-Driven Ribonuclease, Molecular Cell (2011), doi:10.1016/j.molcel.2011.03.002
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/26000
Co-author Elif Sarinay Cenik is a student in the Biochemistry & Molecular Pharmacology program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.
Related ResourcesLink to article in PubMed