Single-stranded antisense siRNAs guide target RNA cleavage in RNAi

Cell. 2002 Sep 6;110(5):563-74. doi: 10.1016/s0092-8674(02)00908-x.


Small interfering RNAs (siRNAs) are the mediators of mRNA degradation in the process of RNA interference (RNAi). Here, we describe a human biochemical system that recapitulates siRNA-mediated target RNA degradation. By using affinity-tagged siRNAs, we demonstrate that a single-stranded siRNA resides in the RNA-induced silencing complex (RISC) together with eIF2C1 and/or eIF2C2 (human GERp95) Argonaute proteins. RISC is rapidly formed in HeLa cell cytoplasmic extract supplemented with 21 nt siRNA duplexes, but also by adding single-stranded antisense RNAs, which range in size between 19 and 29 nucleotides. Single-stranded antisense siRNAs are also effectively silencing genes in HeLa cells, especially when 5'-phosphorylated, and expand the repertoire of RNA reagents suitable for gene targeting.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Gene Silencing*
  • Gene Targeting
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Phosphorylation
  • RNA / metabolism*
  • RNA, Antisense / metabolism*
  • RNA, Small Interfering / analysis
  • RNA, Small Interfering / metabolism*


  • RNA, Antisense
  • RNA, Small Interfering
  • RNA