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Cleavage of the siRNA passenger strand during RISC assembly in human cells
Author(s) -
Leuschner Philipp J F,
Ameres Stefan L,
Kueng Stephanie,
Martinez Javier
Publication year - 2006
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.7400637
Subject(s) - phosphodiester bond , cleavage (geology) , rna interference , rna , small interfering rna , microbiology and biotechnology , gene silencing , rna induced silencing complex , rna silencing , cleavage stimulation factor , argonaute , biology , cleavage and polyadenylation specificity factor , chemistry , cleavage factor , gene , biochemistry , polyadenylation , paleontology , fracture (geology)
A crucial step in the RNA interference (RNAi) pathway involves the assembly of RISC, the RNA‐induced silencing complex. RISC initially recognizes a double‐stranded short interfering RNA (siRNA), but only one strand is finally retained in the functional ribonucleoprotein complex. The non‐incorporated strand, or ‘passenger’ strand, is removed during the assembly process and most probably degraded thereafter. In this report, we show that the passenger strand is cleaved during the course of RISC assembly following the same rules established for the siRNA‐guided cleavage of a target RNA. Chemical modifications impairing the cleavage of the passenger strand also impair the cleavage of a target RNA in vitro as well as the silencing of a reporter gene in vivo , suggesting that passenger strand removal is facilitated by its cleavage during RISC assembly. Interestingly, target RNA cleavage can be rescued if an otherwise non‐cleavable passenger strand shows a nick at the scissile phosphodiester bond, which further indicates that the cleavage event per se is not essential.