Novel LOTUS-domain proteins are organizational hubs that recruit C. elegans Vasa to germ granules


  • P.G. Cipriani
  • O. Bay
  • J. Zinno
  • M. Gutwein
  • H.H. Gan
  • V.K. Mayya
  • G. Chung
  • J.X. Chen
  • H. Fahs
  • Y. Guan
  • T.F. Duchaine
  • M. Selbach
  • F. Piano
  • K.C. Gunsalus


  • eLife


  • eLife 10: e60833


  • We describe MIP-1 and MIP-2, novel paralogous C. elegans germ granule components that interact with the intrinsically disordered MEG-3 protein. These proteins promote P granule condensation, form granules independently of MEG-3 in the postembryonic germ line, and balance each other in regulating P granule growth and localization. MIP-1 and MIP-2 each contain two LOTUS domains and intrinsically disordered regions and form homo- and heterodimers. They bind and anchor the Vasa homolog GLH-1 within P granules and are jointly required for coalescence of MEG-3, GLH-1, and PGL proteins. Animals lacking MIP-1 and MIP-2 show temperature-sensitive embryonic lethality, sterility, and mortal germ lines. Germline phenotypes include defects in stem cell self-renewal, meiotic progression, and gamete differentiation. We propose that these proteins serve as scaffolds and organizing centers for ribonucleoprotein networks within P granules that help recruit and balance essential RNA processing machinery to regulate key developmental transitions in the germ line.