RT Journal Article
SR Electronic
T1 Liquid droplet germ granules require assembly and localized regulators for mRNA repression
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 382838
DO 10.1101/382838
A1 Scott Takeo Aoki
A1 Tina R Lynch
A1 Sarah L Crittenden
A1 Craig A Bingman
A1 Marvin Wickens
A1 Judith Kimble
YR 2019
UL http://biorxiv.org/content/early/2019/07/05/382838.abstract
AB 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, called PGL, 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 granules. We determine the crystal structure of the PGL N-terminal region to 1.5 Å, discover its dimerization and identify key residues at the dimer interface. In vivo mutations of those interface residues prevent P-granule assembly, de-repress PGL-tethered mRNA and reduce fertility. Therefore, PGL 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-tethered mRNA. We conclude that P-granule function requires both assembly and localized regulators.