An RNA-directed nuclease mediates post-transcriptional gene silencing in Drosophila cells

Nature. 2000 Mar 16;404(6775):293-6. doi: 10.1038/35005107.


In a diverse group of organisms that includes Caenorhabditis elegans, Drosophila, planaria, hydra, trypanosomes, fungi and plants, the introduction of double-stranded RNAs inhibits gene expression in a sequence-specific manner. These responses, called RNA interference or post-transcriptional gene silencing, may provide anti-viral defence, modulate transposition or regulate gene expression. We have taken a biochemical approach towards elucidating the mechanisms underlying this genetic phenomenon. Here we show that 'loss-of-function' phenotypes can be created in cultured Drosophila cells by transfection with specific double-stranded RNAs. This coincides with a marked reduction in the level of cognate cellular messenger RNAs. Extracts of transfected cells contain a nuclease activity that specifically degrades exogenous transcripts homologous to transfected double-stranded RNA. This enzyme contains an essential RNA component. After partial purification, the sequence-specific nuclease co-fractionates with a discrete, approximately 25-nucleotide RNA species which may confer specificity to the enzyme through homology to the substrate mRNAs.

Publication types

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

MeSH terms

  • Animals
  • CD8 Antigens / genetics
  • Cell Cycle / genetics
  • Cells, Cultured
  • Cyclin E / genetics
  • Drosophila
  • Endoribonucleases / metabolism*
  • Gene Silencing*
  • Humans
  • Lac Operon
  • RNA, Double-Stranded / physiology*
  • RNA, Messenger / metabolism
  • Substrate Specificity
  • Transcription, Genetic
  • Transfection


  • CD8 Antigens
  • Cyclin E
  • RNA, Double-Stranded
  • RNA, Messenger
  • Endoribonucleases
  • ds RNase