Phosphate and R2D2 restrict the substrate specificity of Dicer-2, an ATP-driven ribonuclease.
Mol Cell
; 42(2): 172-84, 2011 Apr 22.
Article
in En
| MEDLINE
| ID: mdl-21419681
ABSTRACT
Drosophila 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphates
/
RNA, Double-Stranded
/
Adenosine Triphosphate
/
RNA Processing, Post-Transcriptional
/
RNA-Binding Proteins
/
RNA Helicases
/
Drosophila Proteins
/
RNA, Small Interfering
/
Ribonuclease III
/
Drosophila melanogaster
Limits:
Animals
Language:
En
Journal:
Mol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2011
Type:
Article
Affiliation country:
United States