Dicer's Helicase Domain Discriminates dsRNA Termini to Promote an Altered Reaction Mode
| Autor: | Noah C. Welker, Ammie A. Krauchuk, Qinghua Liu, Brenda L. Bass, Tuhin S. Maity, Xuecheng Ye, P. Joseph Aruscavage |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Ribonuclease III
Small interfering RNA Amino Acid Motifs genetic processes Models Biological Article 03 medical and health sciences Adenosine Triphosphate 0302 clinical medicine Animals RNA Small Interfering Caenorhabditis elegans Molecular Biology RNA Double-Stranded 030304 developmental biology 0303 health sciences biology fungi RNA Helicase MDA5 Cell Biology Molecular biology RNA Helicase A Protein Structure Tertiary Cell biology MicroRNAs RNA silencing enzymes and coenzymes (carbohydrates) Mutation biology.protein Drosophila 030217 neurology & neurosurgery Dicer |
| Zdroj: | Molecular Cell. 41(5):589-599 |
| ISSN: | 1097-2765 |
| DOI: | 10.1016/j.molcel.2011.02.005 |
| Popis: | The role of Dicer's helicase domain is enigmatic, but in vivo it is required for processing certain endogenous siRNA, but not miRNA. By using Caenorhabditis elegans extracts or purified Drosophila Dicer-2 we compared activities of wild-type enzymes and those containing mutations in the helicase domain. We found the helicase domain was essential for cleaving dsRNA with blunt or 5'-overhanging termini, but not those with 3' overhangs, as found on miRNA precursors. Further, blunt termini, but not 3' overhangs, led to increased siRNAs from internal regions of dsRNA; this activity required ATP and a functional helicase domain. Our data suggest that blunt or 5'-overhanging termini engage Dicer's helicase domain to facilitate accumulation of siRNAs from internal regions of a dsRNA, an activity suited for processing long siRNA precursors of low abundance, but not necessary for the single cleavage required for miRNA processing. |
| Databáze: | OpenAIRE |
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