title: RDE-2 interacts with MUT-7 to mediate RNA interference in Caenorhabditis elegans.
abstract: In Caenorhabditis elegans, the activity of transposable elements is repressed in the germline. One of the mechanisms involved in this repression is RNA interference (RNAi), a process in which dsRNA targets cleavage of mRNAs in a sequence-specific manner. The first gene found to be involved in RNAi and transposon silencing in C.elegans is mut-7, a gene encoding a putative exoribonuclease. Here, we show that the MUT-7 protein resides in complexes of approximately 250 kDa in the nucleus and in the cytosol. In addition, we find that upon triggering of RNAi the cytosolic MUT-7 complex increases in size. This increase is independent of the presence of target RNA, but does depend on the presence of RDE-1 and RDE-4, two proteins involved in small interfering RNA (siRNA) production. Finally, using a yeast two-hybrid screen, we identified RDE-2/MUT-8 as one of the other components of this complex. This protein is encoded by the rde-2/mut-8 locus, previously implicated in RNAi and transposon silencing. Using genetic complementation analysis, we show that the interaction between these two proteins is required for efficient RNAi in vivo. Together these data support a role for the MUT-7/RDE-2 complex downstream of siRNA formation, but upstream of siRNA mediated target RNA recognition, possibly indicating a role in the siRNA amplification step.
authors.affiliation: Hubrecht Laboratory, Centre for Biomedical Genetics Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
authors.forename: Bastiaan B J
authors.initials: BB
authors.lastname: Tops
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tabara
authors.forename: Titia
authors.initials: T
authors.lastname: Sijen
authors.forename: Femke
authors.initials: F
authors.lastname: Simmer
authors.forename: Craig C
authors.initials: CC
authors.lastname: Mello
authors.forename: Ronald H A
authors.initials: RH
authors.lastname: Plasterk
authors.forename: René F
authors.initials: RF
authors.lastname: Ketting
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005095:Exoribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015723:Gene Library; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D020798:Two-Hybrid System Techniques
chemical_list: D018528:ATP-Binding Cassette Transporters; D029742:Caenorhabditis elegans Proteins; C529203:RDE-2 protein, C elegans; D005095:Exoribonucleases; C496085:MUT-7 protein, C elegans