C. elegans germ granules require both assembly and localized regulators for mRNA repression

Nat Commun. 2021 Feb 12;12(1):996. doi: 10.1038/s41467-021-21278-1.


Cytoplasmic RNA-protein (RNP) granules have diverse biophysical properties, from liquid to solid, and play enigmatic roles in RNA metabolism. Nematode P granules are paradigmatic liquid droplet granules and central to germ cell development. Here we analyze a key P granule scaffolding protein, PGL-1, to investigate the functional relationship between P granule assembly and function. Using a protein-RNA tethering assay, we find that reporter mRNA expression is repressed when recruited to PGL-1. We determine the crystal structure of the PGL-1 N-terminal region to 1.5 Å, discover its dimerization, and identify key residues at the dimer interface. Mutations of those interface residues prevent P granule assembly in vivo, de-repress PGL-1 tethered mRNA, and reduce fertility. Therefore, PGL-1 dimerization lies at the heart of both P granule assembly and function. Finally, we identify the P granule-associated Argonaute WAGO-1 as crucial for repression of PGL-1 tethered mRNA. We conclude that P granule function requires both assembly and localized regulators.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Cytoplasmic Granules / metabolism*
  • Epigenetic Repression
  • Gene Expression Regulation
  • Germ Cells / metabolism*
  • Promoter Regions, Genetic
  • Protein Conformation
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism


  • Caenorhabditis elegans Proteins
  • PGL-1 protein, C elegans
  • RNA, Messenger
  • RNA-Binding Proteins