PPW-1, a PAZ/PIWI protein required for efficient germline RNAi, is defective in a natural isolate of C. elegans

Curr Biol. 2002 Sep 3;12(17):1535-40. doi: 10.1016/s0960-9822(02)01110-7.


One of the remarkable aspects about RNA interference (RNAi) in Caenorhabditis elegans is that the trigger molecules, dsRNA, can be administered via the animal's food. We assayed whether this feature is a universal property of the species by testing numerous strains that have been isolated from different parts of the globe. We found that one isolate from Hawaii had a defect in RNAi that was specific to the germline and was a result of multiple mutations in a PAZ/PIWI domain-containing protein, which we named PPW-1. Deleting ppw-1 in the canonical C. elegans strain Bristol N2 makes it resistant to feeding of dsRNA directed against germline-expressed genes. PPW-1 belongs to the Argonaute family of proteins, which act in posttranscriptional gene silencing and development, and is homologous to the RNAi gene rde-1. Our data indicate that at least two members of this family are required for complete and effective RNAi in C. elegans.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / physiology
  • Eating
  • England
  • Gene Silencing*
  • Genes, Helminth
  • Hawaii
  • Molecular Sequence Data
  • Multigene Family
  • Phenotype
  • Protein Structure, Tertiary
  • RNA Interference*
  • RNA, Double-Stranded / administration & dosage
  • RNA, Small Interfering / genetics*
  • Species Specificity


  • Caenorhabditis elegans Proteins
  • RNA, Double-Stranded
  • RNA, Small Interfering