R2D2 organizes small regulatory RNA pathways in Drosophila Journal Article

Authors: Okamura, K.; Robine, N.; Liu, Y.; Liu, Q.; Lai, E. C.
Article Title: R2D2 organizes small regulatory RNA pathways in Drosophila
Abstract: Drosophila microRNAs (miRNAs) and small interfering RNAs (siRNAs) are generally produced by different Dicer enzymes (Dcr-1 and Dcr-2) and sorted to functionally distinct Argonaute effectors (AGO1 and AGO2). However, there is cross talk between these pathways, as highlighted by the recognition that Drosophila miRNA* strands (the partner strands of mature miRNAs) are generated by Dcr-1 but are preferentially sorted to AGO2. Here, we show that a component of the siRNA loading complex, R2D2, is essential both to load endogenously encoded siRNAs (endo-siRNAs) into AGO2 and to prevent endosiRNAs from binding to AGO1. Northern blot analysis and deep sequencing showed that in the r2d2 mutant, all classes of endo-siRNAs were unable to load AGO2 and instead accumulated in the AGO1 complex. Such redirection was specific to endo-siRNAs and was not observed with miRNA* strands. We observed functional consequences of altered sorting in RNA interference (RNAi) mutants, since endosiRNAs generated from cis-natural antisense transcripts (cis-NAT-siRNA) exhibited evidence for biased maturation as single strands in AGO1 according to thermodynamic asymmetry and a hairpin-derived endo-siRNA formed cleavage-competent complexes with AGO1 upon mutation of r2d2. Finally, we demonstrated a direct role for the R2D2/Dcr-2 heterodimer in sensing central mismatch positions that direct miRNA* strands to AGO2. Together, these data reveal new roles of R2D2 in organizing small RNA networks in Drosophila. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Keywords: unclassified drug; gene mutation; nonhuman; microrna; embryo; animal experiment; small interfering rna; drosophila; rna interference; in vitro study; rna binding protein; nucleotide sequence; gene control; thermodynamics; argonaute 1 protein; argonaute 2 protein; protein rna binding; dcr 2 enzyme; protein r2d2
Journal Title: Molecular and Cellular Biology
Volume: 31
Issue: 4
ISSN: 0270-7306
Publisher: American Society for Microbiology  
Date Published: 2011-02-01
Start Page: 884
End Page: 896
Language: English
DOI: 10.1128/mcb.01141-10
PROVIDER: scopus
PMCID: PMC3028645
PUBMED: 21135122
Notes: --- - "Export Date: 4 March 2011" - "CODEN: MCEBD" - "Source: Scopus"
Citation Impact
MSK Authors
  1. Eric C Lai
    146 Lai
  2. Nicolas Robine
    11 Robine
  3. Katsutomo Okamura
    26 Okamura