title: The Caenorhabditis elegans RDE-10/RDE-11 complex regulates RNAi by promoting secondary siRNA amplification.
abstract: BACKGROUND
  In nematodes, plants, and fungi, RNAi is remarkably potent and persistent due to the amplification of initial silencing signals by RNA-dependent RNA polymerases (RdRPs). In Caenorhabditis elegans (C. elegans), the interaction between the RNA-induced silencing complex (RISC) loaded with primary small interfering RNAs (siRNAs) and the target messenger RNA (mRNA) leads to the recruitment of RdRPs and synthesis of secondary siRNAs using the target mRNA as the template. The mechanism and genetic requirements for secondary siRNA accumulation are not well understood.
  
  
  RESULTS
  From a forward genetic screen for C. elegans genes required for RNAi, we identified rde-10, and through proteomic analysis of RDE-10-interacting proteins, we identified a protein complex containing the new RNAi factor RDE-11, the known RNAi factors RSD-2 and ERGO-1, and other candidate RNAi factors. The RNAi defective genes rde-10 and rde-11 encode a novel protein and a RING-type zinc finger domain protein, respectively. Mutations in rde-10 and rde-11 genes cause dosage-sensitive RNAi deficiencies: these mutants are resistant to low dosage but sensitive to high dosage of double-stranded RNAs. We assessed the roles of rde-10, rde-11, and other dosage-sensitive RNAi-defective genes rsd-2, rsd-6, and haf-6 in both exogenous and endogenous small RNA pathways using high-throughput sequencing and qRT-PCR. These genes are required for the accumulation of secondary siRNAs in both exogenous and endogenous RNAi pathways.
  
  
  CONCLUSIONS
  The RDE-10/RDE-11 complex is essential for the amplification of RNAi in C. elegans by promoting secondary siRNA accumulation.
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Taiowa A
authors.initials: TA
authors.lastname: Montgomery
authors.forename: Sylvia E J
authors.initials: SE
authors.lastname: Fischer
authors.forename: Susana M D A
authors.initials: SM
authors.lastname: Garcia
authors.forename: Christian G
authors.initials: CG
authors.lastname: Riedel
authors.forename: Noah
authors.initials: N
authors.lastname: Fahlgren
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Sullivan
authors.forename: James C
authors.initials: JC
authors.lastname: Carrington
authors.forename: Gary
authors.initials: G
authors.lastname: Ruvkun
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D034743:RNA-Induced Silencing Complex / Q000235:genetics / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C548334:ERGO-1 protein, C elegans; C572735:RDE-10 protein, C elegans; C572736:RDE-11 protein, C elegans; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D034743:RNA-Induced Silencing Complex; C529657:RSD-2 protein, C elegans