Protease-mediated processing of Argonaute proteins controls small RNA association

Mol Cell. 2021 Jun 3;81(11):2388-2402.e8. doi: 10.1016/j.molcel.2021.03.029. Epub 2021 Apr 13.


Small RNA pathways defend the germlines of animals against selfish genetic elements, yet pathway activities need to be contained to prevent silencing of self genes. Here, we reveal a proteolytic mechanism that controls endogenous small interfering (22G) RNA activity in the Caenorhabditis elegans germline to protect genome integrity and maintain fertility. We find that DPF-3, a P-granule-localized N-terminal dipeptidase orthologous to mammalian dipeptidyl peptidase (DPP) 8/9, processes the unusually proline-rich N termini of WAGO-1 and WAGO-3 Argonaute (Ago) proteins. Without DPF-3 activity, these WAGO proteins lose their proper complement of 22G RNAs. Desilencing of repeat-containing and transposon-derived transcripts, DNA damage, and acute sterility ensue. These phenotypes are recapitulated when WAGO-1 and WAGO-3 are rendered resistant to DPF-3-mediated processing, identifying them as critical substrates of DPF-3. We conclude that N-terminal processing of Ago proteins regulates their activity and promotes silencing of selfish genetic elements by ensuring Ago association with appropriate small RNAs.

Keywords: 22G RNA; C. elegans; DPF-3; DPP8; DPP9; DPPIV; Dipeptidyl peptidase; P-granule; WAGO-1; WAGO-3.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Argonaute Proteins / genetics*
  • Argonaute Proteins / metabolism
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics*
  • Caenorhabditis elegans Proteins / metabolism
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / genetics*
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / metabolism
  • Fertility / genetics
  • Protein Processing, Post-Translational*
  • Proteolysis
  • RNA, Helminth / antagonists & inhibitors
  • RNA, Helminth / genetics*
  • RNA, Helminth / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Substrate Specificity


  • Argonaute Proteins
  • Caenorhabditis elegans Proteins
  • RNA, Helminth
  • RNA, Messenger
  • RNA, Small Interfering
  • Dipeptidyl-Peptidases and Tripeptidyl-Peptidases